| 1 | /* GNU/Linux native-dependent code common to multiple platforms. |
| 2 | |
| 3 | Copyright (C) 2001-2012 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "inferior.h" |
| 22 | #include "target.h" |
| 23 | #include "gdb_string.h" |
| 24 | #include "gdb_wait.h" |
| 25 | #include "gdb_assert.h" |
| 26 | #ifdef HAVE_TKILL_SYSCALL |
| 27 | #include <unistd.h> |
| 28 | #include <sys/syscall.h> |
| 29 | #endif |
| 30 | #include <sys/ptrace.h> |
| 31 | #include "linux-nat.h" |
| 32 | #include "linux-ptrace.h" |
| 33 | #include "linux-procfs.h" |
| 34 | #include "linux-fork.h" |
| 35 | #include "gdbthread.h" |
| 36 | #include "gdbcmd.h" |
| 37 | #include "regcache.h" |
| 38 | #include "regset.h" |
| 39 | #include "inf-child.h" |
| 40 | #include "inf-ptrace.h" |
| 41 | #include "auxv.h" |
| 42 | #include <sys/param.h> /* for MAXPATHLEN */ |
| 43 | #include <sys/procfs.h> /* for elf_gregset etc. */ |
| 44 | #include "elf-bfd.h" /* for elfcore_write_* */ |
| 45 | #include "gregset.h" /* for gregset */ |
| 46 | #include "gdbcore.h" /* for get_exec_file */ |
| 47 | #include <ctype.h> /* for isdigit */ |
| 48 | #include "gdbthread.h" /* for struct thread_info etc. */ |
| 49 | #include "gdb_stat.h" /* for struct stat */ |
| 50 | #include <fcntl.h> /* for O_RDONLY */ |
| 51 | #include "inf-loop.h" |
| 52 | #include "event-loop.h" |
| 53 | #include "event-top.h" |
| 54 | #include <pwd.h> |
| 55 | #include <sys/types.h> |
| 56 | #include "gdb_dirent.h" |
| 57 | #include "xml-support.h" |
| 58 | #include "terminal.h" |
| 59 | #include <sys/vfs.h> |
| 60 | #include "solib.h" |
| 61 | #include "linux-osdata.h" |
| 62 | #include "linux-tdep.h" |
| 63 | #include "symfile.h" |
| 64 | #include "agent.h" |
| 65 | #include "tracepoint.h" |
| 66 | #include "exceptions.h" |
| 67 | #include "linux-ptrace.h" |
| 68 | #include "buffer.h" |
| 69 | |
| 70 | #ifndef SPUFS_MAGIC |
| 71 | #define SPUFS_MAGIC 0x23c9b64e |
| 72 | #endif |
| 73 | |
| 74 | #ifdef HAVE_PERSONALITY |
| 75 | # include <sys/personality.h> |
| 76 | # if !HAVE_DECL_ADDR_NO_RANDOMIZE |
| 77 | # define ADDR_NO_RANDOMIZE 0x0040000 |
| 78 | # endif |
| 79 | #endif /* HAVE_PERSONALITY */ |
| 80 | |
| 81 | /* This comment documents high-level logic of this file. |
| 82 | |
| 83 | Waiting for events in sync mode |
| 84 | =============================== |
| 85 | |
| 86 | When waiting for an event in a specific thread, we just use waitpid, passing |
| 87 | the specific pid, and not passing WNOHANG. |
| 88 | |
| 89 | When waiting for an event in all threads, waitpid is not quite good. Prior to |
| 90 | version 2.4, Linux can either wait for event in main thread, or in secondary |
| 91 | threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might |
| 92 | miss an event. The solution is to use non-blocking waitpid, together with |
| 93 | sigsuspend. First, we use non-blocking waitpid to get an event in the main |
| 94 | process, if any. Second, we use non-blocking waitpid with the __WCLONED |
| 95 | flag to check for events in cloned processes. If nothing is found, we use |
| 96 | sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something |
| 97 | happened to a child process -- and SIGCHLD will be delivered both for events |
| 98 | in main debugged process and in cloned processes. As soon as we know there's |
| 99 | an event, we get back to calling nonblocking waitpid with and without |
| 100 | __WCLONED. |
| 101 | |
| 102 | Note that SIGCHLD should be blocked between waitpid and sigsuspend calls, |
| 103 | so that we don't miss a signal. If SIGCHLD arrives in between, when it's |
| 104 | blocked, the signal becomes pending and sigsuspend immediately |
| 105 | notices it and returns. |
| 106 | |
| 107 | Waiting for events in async mode |
| 108 | ================================ |
| 109 | |
| 110 | In async mode, GDB should always be ready to handle both user input |
| 111 | and target events, so neither blocking waitpid nor sigsuspend are |
| 112 | viable options. Instead, we should asynchronously notify the GDB main |
| 113 | event loop whenever there's an unprocessed event from the target. We |
| 114 | detect asynchronous target events by handling SIGCHLD signals. To |
| 115 | notify the event loop about target events, the self-pipe trick is used |
| 116 | --- a pipe is registered as waitable event source in the event loop, |
| 117 | the event loop select/poll's on the read end of this pipe (as well on |
| 118 | other event sources, e.g., stdin), and the SIGCHLD handler writes a |
| 119 | byte to this pipe. This is more portable than relying on |
| 120 | pselect/ppoll, since on kernels that lack those syscalls, libc |
| 121 | emulates them with select/poll+sigprocmask, and that is racy |
| 122 | (a.k.a. plain broken). |
| 123 | |
| 124 | Obviously, if we fail to notify the event loop if there's a target |
| 125 | event, it's bad. OTOH, if we notify the event loop when there's no |
| 126 | event from the target, linux_nat_wait will detect that there's no real |
| 127 | event to report, and return event of type TARGET_WAITKIND_IGNORE. |
| 128 | This is mostly harmless, but it will waste time and is better avoided. |
| 129 | |
| 130 | The main design point is that every time GDB is outside linux-nat.c, |
| 131 | we have a SIGCHLD handler installed that is called when something |
| 132 | happens to the target and notifies the GDB event loop. Whenever GDB |
| 133 | core decides to handle the event, and calls into linux-nat.c, we |
| 134 | process things as in sync mode, except that the we never block in |
| 135 | sigsuspend. |
| 136 | |
| 137 | While processing an event, we may end up momentarily blocked in |
| 138 | waitpid calls. Those waitpid calls, while blocking, are guarantied to |
| 139 | return quickly. E.g., in all-stop mode, before reporting to the core |
| 140 | that an LWP hit a breakpoint, all LWPs are stopped by sending them |
| 141 | SIGSTOP, and synchronously waiting for the SIGSTOP to be reported. |
| 142 | Note that this is different from blocking indefinitely waiting for the |
| 143 | next event --- here, we're already handling an event. |
| 144 | |
| 145 | Use of signals |
| 146 | ============== |
| 147 | |
| 148 | We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another |
| 149 | signal is not entirely significant; we just need for a signal to be delivered, |
| 150 | so that we can intercept it. SIGSTOP's advantage is that it can not be |
| 151 | blocked. A disadvantage is that it is not a real-time signal, so it can only |
| 152 | be queued once; we do not keep track of other sources of SIGSTOP. |
| 153 | |
| 154 | Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't |
| 155 | use them, because they have special behavior when the signal is generated - |
| 156 | not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL |
| 157 | kills the entire thread group. |
| 158 | |
| 159 | A delivered SIGSTOP would stop the entire thread group, not just the thread we |
| 160 | tkill'd. But we never let the SIGSTOP be delivered; we always intercept and |
| 161 | cancel it (by PTRACE_CONT without passing SIGSTOP). |
| 162 | |
| 163 | We could use a real-time signal instead. This would solve those problems; we |
| 164 | could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB. |
| 165 | But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH |
| 166 | generates it, and there are races with trying to find a signal that is not |
| 167 | blocked. */ |
| 168 | |
| 169 | #ifndef O_LARGEFILE |
| 170 | #define O_LARGEFILE 0 |
| 171 | #endif |
| 172 | |
| 173 | /* Unlike other extended result codes, WSTOPSIG (status) on |
| 174 | PTRACE_O_TRACESYSGOOD syscall events doesn't return SIGTRAP, but |
| 175 | instead SIGTRAP with bit 7 set. */ |
| 176 | #define SYSCALL_SIGTRAP (SIGTRAP | 0x80) |
| 177 | |
| 178 | /* The single-threaded native GNU/Linux target_ops. We save a pointer for |
| 179 | the use of the multi-threaded target. */ |
| 180 | static struct target_ops *linux_ops; |
| 181 | static struct target_ops linux_ops_saved; |
| 182 | |
| 183 | /* The method to call, if any, when a new thread is attached. */ |
| 184 | static void (*linux_nat_new_thread) (struct lwp_info *); |
| 185 | |
| 186 | /* Hook to call prior to resuming a thread. */ |
| 187 | static void (*linux_nat_prepare_to_resume) (struct lwp_info *); |
| 188 | |
| 189 | /* The method to call, if any, when the siginfo object needs to be |
| 190 | converted between the layout returned by ptrace, and the layout in |
| 191 | the architecture of the inferior. */ |
| 192 | static int (*linux_nat_siginfo_fixup) (siginfo_t *, |
| 193 | gdb_byte *, |
| 194 | int); |
| 195 | |
| 196 | /* The saved to_xfer_partial method, inherited from inf-ptrace.c. |
| 197 | Called by our to_xfer_partial. */ |
| 198 | static LONGEST (*super_xfer_partial) (struct target_ops *, |
| 199 | enum target_object, |
| 200 | const char *, gdb_byte *, |
| 201 | const gdb_byte *, |
| 202 | ULONGEST, LONGEST); |
| 203 | |
| 204 | static int debug_linux_nat; |
| 205 | static void |
| 206 | show_debug_linux_nat (struct ui_file *file, int from_tty, |
| 207 | struct cmd_list_element *c, const char *value) |
| 208 | { |
| 209 | fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"), |
| 210 | value); |
| 211 | } |
| 212 | |
| 213 | struct simple_pid_list |
| 214 | { |
| 215 | int pid; |
| 216 | int status; |
| 217 | struct simple_pid_list *next; |
| 218 | }; |
| 219 | struct simple_pid_list *stopped_pids; |
| 220 | |
| 221 | /* This variable is a tri-state flag: -1 for unknown, 0 if PTRACE_O_TRACEFORK |
| 222 | can not be used, 1 if it can. */ |
| 223 | |
| 224 | static int linux_supports_tracefork_flag = -1; |
| 225 | |
| 226 | /* This variable is a tri-state flag: -1 for unknown, 0 if |
| 227 | PTRACE_O_TRACESYSGOOD can not be used, 1 if it can. */ |
| 228 | |
| 229 | static int linux_supports_tracesysgood_flag = -1; |
| 230 | |
| 231 | /* If we have PTRACE_O_TRACEFORK, this flag indicates whether we also have |
| 232 | PTRACE_O_TRACEVFORKDONE. */ |
| 233 | |
| 234 | static int linux_supports_tracevforkdone_flag = -1; |
| 235 | |
| 236 | /* Stores the current used ptrace() options. */ |
| 237 | static int current_ptrace_options = 0; |
| 238 | |
| 239 | /* Async mode support. */ |
| 240 | |
| 241 | /* The read/write ends of the pipe registered as waitable file in the |
| 242 | event loop. */ |
| 243 | static int linux_nat_event_pipe[2] = { -1, -1 }; |
| 244 | |
| 245 | /* Flush the event pipe. */ |
| 246 | |
| 247 | static void |
| 248 | async_file_flush (void) |
| 249 | { |
| 250 | int ret; |
| 251 | char buf; |
| 252 | |
| 253 | do |
| 254 | { |
| 255 | ret = read (linux_nat_event_pipe[0], &buf, 1); |
| 256 | } |
| 257 | while (ret >= 0 || (ret == -1 && errno == EINTR)); |
| 258 | } |
| 259 | |
| 260 | /* Put something (anything, doesn't matter what, or how much) in event |
| 261 | pipe, so that the select/poll in the event-loop realizes we have |
| 262 | something to process. */ |
| 263 | |
| 264 | static void |
| 265 | async_file_mark (void) |
| 266 | { |
| 267 | int ret; |
| 268 | |
| 269 | /* It doesn't really matter what the pipe contains, as long we end |
| 270 | up with something in it. Might as well flush the previous |
| 271 | left-overs. */ |
| 272 | async_file_flush (); |
| 273 | |
| 274 | do |
| 275 | { |
| 276 | ret = write (linux_nat_event_pipe[1], "+", 1); |
| 277 | } |
| 278 | while (ret == -1 && errno == EINTR); |
| 279 | |
| 280 | /* Ignore EAGAIN. If the pipe is full, the event loop will already |
| 281 | be awakened anyway. */ |
| 282 | } |
| 283 | |
| 284 | static void linux_nat_async (void (*callback) |
| 285 | (enum inferior_event_type event_type, |
| 286 | void *context), |
| 287 | void *context); |
| 288 | static int kill_lwp (int lwpid, int signo); |
| 289 | |
| 290 | static int stop_callback (struct lwp_info *lp, void *data); |
| 291 | |
| 292 | static void block_child_signals (sigset_t *prev_mask); |
| 293 | static void restore_child_signals_mask (sigset_t *prev_mask); |
| 294 | |
| 295 | struct lwp_info; |
| 296 | static struct lwp_info *add_lwp (ptid_t ptid); |
| 297 | static void purge_lwp_list (int pid); |
| 298 | static void delete_lwp (ptid_t ptid); |
| 299 | static struct lwp_info *find_lwp_pid (ptid_t ptid); |
| 300 | |
| 301 | \f |
| 302 | /* Trivial list manipulation functions to keep track of a list of |
| 303 | new stopped processes. */ |
| 304 | static void |
| 305 | add_to_pid_list (struct simple_pid_list **listp, int pid, int status) |
| 306 | { |
| 307 | struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list)); |
| 308 | |
| 309 | new_pid->pid = pid; |
| 310 | new_pid->status = status; |
| 311 | new_pid->next = *listp; |
| 312 | *listp = new_pid; |
| 313 | } |
| 314 | |
| 315 | static int |
| 316 | in_pid_list_p (struct simple_pid_list *list, int pid) |
| 317 | { |
| 318 | struct simple_pid_list *p; |
| 319 | |
| 320 | for (p = list; p != NULL; p = p->next) |
| 321 | if (p->pid == pid) |
| 322 | return 1; |
| 323 | return 0; |
| 324 | } |
| 325 | |
| 326 | static int |
| 327 | pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp) |
| 328 | { |
| 329 | struct simple_pid_list **p; |
| 330 | |
| 331 | for (p = listp; *p != NULL; p = &(*p)->next) |
| 332 | if ((*p)->pid == pid) |
| 333 | { |
| 334 | struct simple_pid_list *next = (*p)->next; |
| 335 | |
| 336 | *statusp = (*p)->status; |
| 337 | xfree (*p); |
| 338 | *p = next; |
| 339 | return 1; |
| 340 | } |
| 341 | return 0; |
| 342 | } |
| 343 | |
| 344 | \f |
| 345 | /* A helper function for linux_test_for_tracefork, called after fork (). */ |
| 346 | |
| 347 | static void |
| 348 | linux_tracefork_child (void) |
| 349 | { |
| 350 | ptrace (PTRACE_TRACEME, 0, 0, 0); |
| 351 | kill (getpid (), SIGSTOP); |
| 352 | fork (); |
| 353 | _exit (0); |
| 354 | } |
| 355 | |
| 356 | /* Wrapper function for waitpid which handles EINTR. */ |
| 357 | |
| 358 | static int |
| 359 | my_waitpid (int pid, int *statusp, int flags) |
| 360 | { |
| 361 | int ret; |
| 362 | |
| 363 | do |
| 364 | { |
| 365 | ret = waitpid (pid, statusp, flags); |
| 366 | } |
| 367 | while (ret == -1 && errno == EINTR); |
| 368 | |
| 369 | return ret; |
| 370 | } |
| 371 | |
| 372 | /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. |
| 373 | |
| 374 | First, we try to enable fork tracing on ORIGINAL_PID. If this fails, |
| 375 | we know that the feature is not available. This may change the tracing |
| 376 | options for ORIGINAL_PID, but we'll be setting them shortly anyway. |
| 377 | |
| 378 | However, if it succeeds, we don't know for sure that the feature is |
| 379 | available; old versions of PTRACE_SETOPTIONS ignored unknown options. We |
| 380 | create a child process, attach to it, use PTRACE_SETOPTIONS to enable |
| 381 | fork tracing, and let it fork. If the process exits, we assume that we |
| 382 | can't use TRACEFORK; if we get the fork notification, and we can extract |
| 383 | the new child's PID, then we assume that we can. */ |
| 384 | |
| 385 | static void |
| 386 | linux_test_for_tracefork (int original_pid) |
| 387 | { |
| 388 | int child_pid, ret, status; |
| 389 | long second_pid; |
| 390 | sigset_t prev_mask; |
| 391 | |
| 392 | /* We don't want those ptrace calls to be interrupted. */ |
| 393 | block_child_signals (&prev_mask); |
| 394 | |
| 395 | linux_supports_tracefork_flag = 0; |
| 396 | linux_supports_tracevforkdone_flag = 0; |
| 397 | |
| 398 | ret = ptrace (PTRACE_SETOPTIONS, original_pid, 0, PTRACE_O_TRACEFORK); |
| 399 | if (ret != 0) |
| 400 | { |
| 401 | restore_child_signals_mask (&prev_mask); |
| 402 | return; |
| 403 | } |
| 404 | |
| 405 | child_pid = fork (); |
| 406 | if (child_pid == -1) |
| 407 | perror_with_name (("fork")); |
| 408 | |
| 409 | if (child_pid == 0) |
| 410 | linux_tracefork_child (); |
| 411 | |
| 412 | ret = my_waitpid (child_pid, &status, 0); |
| 413 | if (ret == -1) |
| 414 | perror_with_name (("waitpid")); |
| 415 | else if (ret != child_pid) |
| 416 | error (_("linux_test_for_tracefork: waitpid: unexpected result %d."), ret); |
| 417 | if (! WIFSTOPPED (status)) |
| 418 | error (_("linux_test_for_tracefork: waitpid: unexpected status %d."), |
| 419 | status); |
| 420 | |
| 421 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK); |
| 422 | if (ret != 0) |
| 423 | { |
| 424 | ret = ptrace (PTRACE_KILL, child_pid, 0, 0); |
| 425 | if (ret != 0) |
| 426 | { |
| 427 | warning (_("linux_test_for_tracefork: failed to kill child")); |
| 428 | restore_child_signals_mask (&prev_mask); |
| 429 | return; |
| 430 | } |
| 431 | |
| 432 | ret = my_waitpid (child_pid, &status, 0); |
| 433 | if (ret != child_pid) |
| 434 | warning (_("linux_test_for_tracefork: failed " |
| 435 | "to wait for killed child")); |
| 436 | else if (!WIFSIGNALED (status)) |
| 437 | warning (_("linux_test_for_tracefork: unexpected " |
| 438 | "wait status 0x%x from killed child"), status); |
| 439 | |
| 440 | restore_child_signals_mask (&prev_mask); |
| 441 | return; |
| 442 | } |
| 443 | |
| 444 | /* Check whether PTRACE_O_TRACEVFORKDONE is available. */ |
| 445 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, |
| 446 | PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORKDONE); |
| 447 | linux_supports_tracevforkdone_flag = (ret == 0); |
| 448 | |
| 449 | ret = ptrace (PTRACE_CONT, child_pid, 0, 0); |
| 450 | if (ret != 0) |
| 451 | warning (_("linux_test_for_tracefork: failed to resume child")); |
| 452 | |
| 453 | ret = my_waitpid (child_pid, &status, 0); |
| 454 | |
| 455 | if (ret == child_pid && WIFSTOPPED (status) |
| 456 | && status >> 16 == PTRACE_EVENT_FORK) |
| 457 | { |
| 458 | second_pid = 0; |
| 459 | ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid); |
| 460 | if (ret == 0 && second_pid != 0) |
| 461 | { |
| 462 | int second_status; |
| 463 | |
| 464 | linux_supports_tracefork_flag = 1; |
| 465 | my_waitpid (second_pid, &second_status, 0); |
| 466 | ret = ptrace (PTRACE_KILL, second_pid, 0, 0); |
| 467 | if (ret != 0) |
| 468 | warning (_("linux_test_for_tracefork: " |
| 469 | "failed to kill second child")); |
| 470 | my_waitpid (second_pid, &status, 0); |
| 471 | } |
| 472 | } |
| 473 | else |
| 474 | warning (_("linux_test_for_tracefork: unexpected result from waitpid " |
| 475 | "(%d, status 0x%x)"), ret, status); |
| 476 | |
| 477 | ret = ptrace (PTRACE_KILL, child_pid, 0, 0); |
| 478 | if (ret != 0) |
| 479 | warning (_("linux_test_for_tracefork: failed to kill child")); |
| 480 | my_waitpid (child_pid, &status, 0); |
| 481 | |
| 482 | restore_child_signals_mask (&prev_mask); |
| 483 | } |
| 484 | |
| 485 | /* Determine if PTRACE_O_TRACESYSGOOD can be used to follow syscalls. |
| 486 | |
| 487 | We try to enable syscall tracing on ORIGINAL_PID. If this fails, |
| 488 | we know that the feature is not available. This may change the tracing |
| 489 | options for ORIGINAL_PID, but we'll be setting them shortly anyway. */ |
| 490 | |
| 491 | static void |
| 492 | linux_test_for_tracesysgood (int original_pid) |
| 493 | { |
| 494 | int ret; |
| 495 | sigset_t prev_mask; |
| 496 | |
| 497 | /* We don't want those ptrace calls to be interrupted. */ |
| 498 | block_child_signals (&prev_mask); |
| 499 | |
| 500 | linux_supports_tracesysgood_flag = 0; |
| 501 | |
| 502 | ret = ptrace (PTRACE_SETOPTIONS, original_pid, 0, PTRACE_O_TRACESYSGOOD); |
| 503 | if (ret != 0) |
| 504 | goto out; |
| 505 | |
| 506 | linux_supports_tracesysgood_flag = 1; |
| 507 | out: |
| 508 | restore_child_signals_mask (&prev_mask); |
| 509 | } |
| 510 | |
| 511 | /* Determine wether we support PTRACE_O_TRACESYSGOOD option available. |
| 512 | This function also sets linux_supports_tracesysgood_flag. */ |
| 513 | |
| 514 | static int |
| 515 | linux_supports_tracesysgood (int pid) |
| 516 | { |
| 517 | if (linux_supports_tracesysgood_flag == -1) |
| 518 | linux_test_for_tracesysgood (pid); |
| 519 | return linux_supports_tracesysgood_flag; |
| 520 | } |
| 521 | |
| 522 | /* Return non-zero iff we have tracefork functionality available. |
| 523 | This function also sets linux_supports_tracefork_flag. */ |
| 524 | |
| 525 | static int |
| 526 | linux_supports_tracefork (int pid) |
| 527 | { |
| 528 | if (linux_supports_tracefork_flag == -1) |
| 529 | linux_test_for_tracefork (pid); |
| 530 | return linux_supports_tracefork_flag; |
| 531 | } |
| 532 | |
| 533 | static int |
| 534 | linux_supports_tracevforkdone (int pid) |
| 535 | { |
| 536 | if (linux_supports_tracefork_flag == -1) |
| 537 | linux_test_for_tracefork (pid); |
| 538 | return linux_supports_tracevforkdone_flag; |
| 539 | } |
| 540 | |
| 541 | static void |
| 542 | linux_enable_tracesysgood (ptid_t ptid) |
| 543 | { |
| 544 | int pid = ptid_get_lwp (ptid); |
| 545 | |
| 546 | if (pid == 0) |
| 547 | pid = ptid_get_pid (ptid); |
| 548 | |
| 549 | if (linux_supports_tracesysgood (pid) == 0) |
| 550 | return; |
| 551 | |
| 552 | current_ptrace_options |= PTRACE_O_TRACESYSGOOD; |
| 553 | |
| 554 | ptrace (PTRACE_SETOPTIONS, pid, 0, current_ptrace_options); |
| 555 | } |
| 556 | |
| 557 | \f |
| 558 | void |
| 559 | linux_enable_event_reporting (ptid_t ptid) |
| 560 | { |
| 561 | int pid = ptid_get_lwp (ptid); |
| 562 | |
| 563 | if (pid == 0) |
| 564 | pid = ptid_get_pid (ptid); |
| 565 | |
| 566 | if (! linux_supports_tracefork (pid)) |
| 567 | return; |
| 568 | |
| 569 | current_ptrace_options |= PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK |
| 570 | | PTRACE_O_TRACEEXEC | PTRACE_O_TRACECLONE; |
| 571 | |
| 572 | if (linux_supports_tracevforkdone (pid)) |
| 573 | current_ptrace_options |= PTRACE_O_TRACEVFORKDONE; |
| 574 | |
| 575 | /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to support |
| 576 | read-only process state. */ |
| 577 | |
| 578 | ptrace (PTRACE_SETOPTIONS, pid, 0, current_ptrace_options); |
| 579 | } |
| 580 | |
| 581 | static void |
| 582 | linux_child_post_attach (int pid) |
| 583 | { |
| 584 | linux_enable_event_reporting (pid_to_ptid (pid)); |
| 585 | linux_enable_tracesysgood (pid_to_ptid (pid)); |
| 586 | linux_ptrace_init_warnings (); |
| 587 | } |
| 588 | |
| 589 | static void |
| 590 | linux_child_post_startup_inferior (ptid_t ptid) |
| 591 | { |
| 592 | linux_enable_event_reporting (ptid); |
| 593 | linux_enable_tracesysgood (ptid); |
| 594 | linux_ptrace_init_warnings (); |
| 595 | } |
| 596 | |
| 597 | /* Return the number of known LWPs in the tgid given by PID. */ |
| 598 | |
| 599 | static int |
| 600 | num_lwps (int pid) |
| 601 | { |
| 602 | int count = 0; |
| 603 | struct lwp_info *lp; |
| 604 | |
| 605 | for (lp = lwp_list; lp; lp = lp->next) |
| 606 | if (ptid_get_pid (lp->ptid) == pid) |
| 607 | count++; |
| 608 | |
| 609 | return count; |
| 610 | } |
| 611 | |
| 612 | /* Call delete_lwp with prototype compatible for make_cleanup. */ |
| 613 | |
| 614 | static void |
| 615 | delete_lwp_cleanup (void *lp_voidp) |
| 616 | { |
| 617 | struct lwp_info *lp = lp_voidp; |
| 618 | |
| 619 | delete_lwp (lp->ptid); |
| 620 | } |
| 621 | |
| 622 | static int |
| 623 | linux_child_follow_fork (struct target_ops *ops, int follow_child) |
| 624 | { |
| 625 | sigset_t prev_mask; |
| 626 | int has_vforked; |
| 627 | int parent_pid, child_pid; |
| 628 | |
| 629 | block_child_signals (&prev_mask); |
| 630 | |
| 631 | has_vforked = (inferior_thread ()->pending_follow.kind |
| 632 | == TARGET_WAITKIND_VFORKED); |
| 633 | parent_pid = ptid_get_lwp (inferior_ptid); |
| 634 | if (parent_pid == 0) |
| 635 | parent_pid = ptid_get_pid (inferior_ptid); |
| 636 | child_pid = PIDGET (inferior_thread ()->pending_follow.value.related_pid); |
| 637 | |
| 638 | if (!detach_fork) |
| 639 | linux_enable_event_reporting (pid_to_ptid (child_pid)); |
| 640 | |
| 641 | if (has_vforked |
| 642 | && !non_stop /* Non-stop always resumes both branches. */ |
| 643 | && (!target_is_async_p () || sync_execution) |
| 644 | && !(follow_child || detach_fork || sched_multi)) |
| 645 | { |
| 646 | /* The parent stays blocked inside the vfork syscall until the |
| 647 | child execs or exits. If we don't let the child run, then |
| 648 | the parent stays blocked. If we're telling the parent to run |
| 649 | in the foreground, the user will not be able to ctrl-c to get |
| 650 | back the terminal, effectively hanging the debug session. */ |
| 651 | fprintf_filtered (gdb_stderr, _("\ |
| 652 | Can not resume the parent process over vfork in the foreground while\n\ |
| 653 | holding the child stopped. Try \"set detach-on-fork\" or \ |
| 654 | \"set schedule-multiple\".\n")); |
| 655 | /* FIXME output string > 80 columns. */ |
| 656 | return 1; |
| 657 | } |
| 658 | |
| 659 | if (! follow_child) |
| 660 | { |
| 661 | struct lwp_info *child_lp = NULL; |
| 662 | |
| 663 | /* We're already attached to the parent, by default. */ |
| 664 | |
| 665 | /* Detach new forked process? */ |
| 666 | if (detach_fork) |
| 667 | { |
| 668 | struct cleanup *old_chain; |
| 669 | |
| 670 | /* Before detaching from the child, remove all breakpoints |
| 671 | from it. If we forked, then this has already been taken |
| 672 | care of by infrun.c. If we vforked however, any |
| 673 | breakpoint inserted in the parent is visible in the |
| 674 | child, even those added while stopped in a vfork |
| 675 | catchpoint. This will remove the breakpoints from the |
| 676 | parent also, but they'll be reinserted below. */ |
| 677 | if (has_vforked) |
| 678 | { |
| 679 | /* keep breakpoints list in sync. */ |
| 680 | remove_breakpoints_pid (GET_PID (inferior_ptid)); |
| 681 | } |
| 682 | |
| 683 | if (info_verbose || debug_linux_nat) |
| 684 | { |
| 685 | target_terminal_ours (); |
| 686 | fprintf_filtered (gdb_stdlog, |
| 687 | "Detaching after fork from " |
| 688 | "child process %d.\n", |
| 689 | child_pid); |
| 690 | } |
| 691 | |
| 692 | old_chain = save_inferior_ptid (); |
| 693 | inferior_ptid = ptid_build (child_pid, child_pid, 0); |
| 694 | |
| 695 | child_lp = add_lwp (inferior_ptid); |
| 696 | child_lp->stopped = 1; |
| 697 | child_lp->last_resume_kind = resume_stop; |
| 698 | make_cleanup (delete_lwp_cleanup, child_lp); |
| 699 | |
| 700 | /* CHILD_LP has new PID, therefore linux_nat_new_thread is not called for it. |
| 701 | See i386_inferior_data_get for the Linux kernel specifics. |
| 702 | Ensure linux_nat_prepare_to_resume will reset the hardware debug |
| 703 | registers. It is done by the linux_nat_new_thread call, which is |
| 704 | being skipped in add_lwp above for the first lwp of a pid. */ |
| 705 | gdb_assert (num_lwps (GET_PID (child_lp->ptid)) == 1); |
| 706 | if (linux_nat_new_thread != NULL) |
| 707 | linux_nat_new_thread (child_lp); |
| 708 | |
| 709 | if (linux_nat_prepare_to_resume != NULL) |
| 710 | linux_nat_prepare_to_resume (child_lp); |
| 711 | ptrace (PTRACE_DETACH, child_pid, 0, 0); |
| 712 | |
| 713 | do_cleanups (old_chain); |
| 714 | } |
| 715 | else |
| 716 | { |
| 717 | struct inferior *parent_inf, *child_inf; |
| 718 | struct cleanup *old_chain; |
| 719 | |
| 720 | /* Add process to GDB's tables. */ |
| 721 | child_inf = add_inferior (child_pid); |
| 722 | |
| 723 | parent_inf = current_inferior (); |
| 724 | child_inf->attach_flag = parent_inf->attach_flag; |
| 725 | copy_terminal_info (child_inf, parent_inf); |
| 726 | |
| 727 | old_chain = save_inferior_ptid (); |
| 728 | save_current_program_space (); |
| 729 | |
| 730 | inferior_ptid = ptid_build (child_pid, child_pid, 0); |
| 731 | add_thread (inferior_ptid); |
| 732 | child_lp = add_lwp (inferior_ptid); |
| 733 | child_lp->stopped = 1; |
| 734 | child_lp->last_resume_kind = resume_stop; |
| 735 | child_inf->symfile_flags = SYMFILE_NO_READ; |
| 736 | |
| 737 | /* If this is a vfork child, then the address-space is |
| 738 | shared with the parent. */ |
| 739 | if (has_vforked) |
| 740 | { |
| 741 | child_inf->pspace = parent_inf->pspace; |
| 742 | child_inf->aspace = parent_inf->aspace; |
| 743 | |
| 744 | /* The parent will be frozen until the child is done |
| 745 | with the shared region. Keep track of the |
| 746 | parent. */ |
| 747 | child_inf->vfork_parent = parent_inf; |
| 748 | child_inf->pending_detach = 0; |
| 749 | parent_inf->vfork_child = child_inf; |
| 750 | parent_inf->pending_detach = 0; |
| 751 | } |
| 752 | else |
| 753 | { |
| 754 | child_inf->aspace = new_address_space (); |
| 755 | child_inf->pspace = add_program_space (child_inf->aspace); |
| 756 | child_inf->removable = 1; |
| 757 | set_current_program_space (child_inf->pspace); |
| 758 | clone_program_space (child_inf->pspace, parent_inf->pspace); |
| 759 | |
| 760 | /* Let the shared library layer (solib-svr4) learn about |
| 761 | this new process, relocate the cloned exec, pull in |
| 762 | shared libraries, and install the solib event |
| 763 | breakpoint. If a "cloned-VM" event was propagated |
| 764 | better throughout the core, this wouldn't be |
| 765 | required. */ |
| 766 | solib_create_inferior_hook (0); |
| 767 | } |
| 768 | |
| 769 | /* Let the thread_db layer learn about this new process. */ |
| 770 | check_for_thread_db (); |
| 771 | |
| 772 | do_cleanups (old_chain); |
| 773 | } |
| 774 | |
| 775 | if (has_vforked) |
| 776 | { |
| 777 | struct lwp_info *parent_lp; |
| 778 | struct inferior *parent_inf; |
| 779 | |
| 780 | parent_inf = current_inferior (); |
| 781 | |
| 782 | /* If we detached from the child, then we have to be careful |
| 783 | to not insert breakpoints in the parent until the child |
| 784 | is done with the shared memory region. However, if we're |
| 785 | staying attached to the child, then we can and should |
| 786 | insert breakpoints, so that we can debug it. A |
| 787 | subsequent child exec or exit is enough to know when does |
| 788 | the child stops using the parent's address space. */ |
| 789 | parent_inf->waiting_for_vfork_done = detach_fork; |
| 790 | parent_inf->pspace->breakpoints_not_allowed = detach_fork; |
| 791 | |
| 792 | parent_lp = find_lwp_pid (pid_to_ptid (parent_pid)); |
| 793 | gdb_assert (linux_supports_tracefork_flag >= 0); |
| 794 | |
| 795 | if (linux_supports_tracevforkdone (0)) |
| 796 | { |
| 797 | if (debug_linux_nat) |
| 798 | fprintf_unfiltered (gdb_stdlog, |
| 799 | "LCFF: waiting for VFORK_DONE on %d\n", |
| 800 | parent_pid); |
| 801 | parent_lp->stopped = 1; |
| 802 | |
| 803 | /* We'll handle the VFORK_DONE event like any other |
| 804 | event, in target_wait. */ |
| 805 | } |
| 806 | else |
| 807 | { |
| 808 | /* We can't insert breakpoints until the child has |
| 809 | finished with the shared memory region. We need to |
| 810 | wait until that happens. Ideal would be to just |
| 811 | call: |
| 812 | - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0); |
| 813 | - waitpid (parent_pid, &status, __WALL); |
| 814 | However, most architectures can't handle a syscall |
| 815 | being traced on the way out if it wasn't traced on |
| 816 | the way in. |
| 817 | |
| 818 | We might also think to loop, continuing the child |
| 819 | until it exits or gets a SIGTRAP. One problem is |
| 820 | that the child might call ptrace with PTRACE_TRACEME. |
| 821 | |
| 822 | There's no simple and reliable way to figure out when |
| 823 | the vforked child will be done with its copy of the |
| 824 | shared memory. We could step it out of the syscall, |
| 825 | two instructions, let it go, and then single-step the |
| 826 | parent once. When we have hardware single-step, this |
| 827 | would work; with software single-step it could still |
| 828 | be made to work but we'd have to be able to insert |
| 829 | single-step breakpoints in the child, and we'd have |
| 830 | to insert -just- the single-step breakpoint in the |
| 831 | parent. Very awkward. |
| 832 | |
| 833 | In the end, the best we can do is to make sure it |
| 834 | runs for a little while. Hopefully it will be out of |
| 835 | range of any breakpoints we reinsert. Usually this |
| 836 | is only the single-step breakpoint at vfork's return |
| 837 | point. */ |
| 838 | |
| 839 | if (debug_linux_nat) |
| 840 | fprintf_unfiltered (gdb_stdlog, |
| 841 | "LCFF: no VFORK_DONE " |
| 842 | "support, sleeping a bit\n"); |
| 843 | |
| 844 | usleep (10000); |
| 845 | |
| 846 | /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event, |
| 847 | and leave it pending. The next linux_nat_resume call |
| 848 | will notice a pending event, and bypasses actually |
| 849 | resuming the inferior. */ |
| 850 | parent_lp->status = 0; |
| 851 | parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE; |
| 852 | parent_lp->stopped = 1; |
| 853 | |
| 854 | /* If we're in async mode, need to tell the event loop |
| 855 | there's something here to process. */ |
| 856 | if (target_can_async_p ()) |
| 857 | async_file_mark (); |
| 858 | } |
| 859 | } |
| 860 | } |
| 861 | else |
| 862 | { |
| 863 | struct inferior *parent_inf, *child_inf; |
| 864 | struct lwp_info *child_lp; |
| 865 | struct program_space *parent_pspace; |
| 866 | |
| 867 | if (info_verbose || debug_linux_nat) |
| 868 | { |
| 869 | target_terminal_ours (); |
| 870 | if (has_vforked) |
| 871 | fprintf_filtered (gdb_stdlog, |
| 872 | _("Attaching after process %d " |
| 873 | "vfork to child process %d.\n"), |
| 874 | parent_pid, child_pid); |
| 875 | else |
| 876 | fprintf_filtered (gdb_stdlog, |
| 877 | _("Attaching after process %d " |
| 878 | "fork to child process %d.\n"), |
| 879 | parent_pid, child_pid); |
| 880 | } |
| 881 | |
| 882 | /* Add the new inferior first, so that the target_detach below |
| 883 | doesn't unpush the target. */ |
| 884 | |
| 885 | child_inf = add_inferior (child_pid); |
| 886 | |
| 887 | parent_inf = current_inferior (); |
| 888 | child_inf->attach_flag = parent_inf->attach_flag; |
| 889 | copy_terminal_info (child_inf, parent_inf); |
| 890 | |
| 891 | parent_pspace = parent_inf->pspace; |
| 892 | |
| 893 | /* If we're vforking, we want to hold on to the parent until the |
| 894 | child exits or execs. At child exec or exit time we can |
| 895 | remove the old breakpoints from the parent and detach or |
| 896 | resume debugging it. Otherwise, detach the parent now; we'll |
| 897 | want to reuse it's program/address spaces, but we can't set |
| 898 | them to the child before removing breakpoints from the |
| 899 | parent, otherwise, the breakpoints module could decide to |
| 900 | remove breakpoints from the wrong process (since they'd be |
| 901 | assigned to the same address space). */ |
| 902 | |
| 903 | if (has_vforked) |
| 904 | { |
| 905 | gdb_assert (child_inf->vfork_parent == NULL); |
| 906 | gdb_assert (parent_inf->vfork_child == NULL); |
| 907 | child_inf->vfork_parent = parent_inf; |
| 908 | child_inf->pending_detach = 0; |
| 909 | parent_inf->vfork_child = child_inf; |
| 910 | parent_inf->pending_detach = detach_fork; |
| 911 | parent_inf->waiting_for_vfork_done = 0; |
| 912 | } |
| 913 | else if (detach_fork) |
| 914 | target_detach (NULL, 0); |
| 915 | |
| 916 | /* Note that the detach above makes PARENT_INF dangling. */ |
| 917 | |
| 918 | /* Add the child thread to the appropriate lists, and switch to |
| 919 | this new thread, before cloning the program space, and |
| 920 | informing the solib layer about this new process. */ |
| 921 | |
| 922 | inferior_ptid = ptid_build (child_pid, child_pid, 0); |
| 923 | add_thread (inferior_ptid); |
| 924 | child_lp = add_lwp (inferior_ptid); |
| 925 | child_lp->stopped = 1; |
| 926 | child_lp->last_resume_kind = resume_stop; |
| 927 | |
| 928 | /* If this is a vfork child, then the address-space is shared |
| 929 | with the parent. If we detached from the parent, then we can |
| 930 | reuse the parent's program/address spaces. */ |
| 931 | if (has_vforked || detach_fork) |
| 932 | { |
| 933 | child_inf->pspace = parent_pspace; |
| 934 | child_inf->aspace = child_inf->pspace->aspace; |
| 935 | } |
| 936 | else |
| 937 | { |
| 938 | child_inf->aspace = new_address_space (); |
| 939 | child_inf->pspace = add_program_space (child_inf->aspace); |
| 940 | child_inf->removable = 1; |
| 941 | child_inf->symfile_flags = SYMFILE_NO_READ; |
| 942 | set_current_program_space (child_inf->pspace); |
| 943 | clone_program_space (child_inf->pspace, parent_pspace); |
| 944 | |
| 945 | /* Let the shared library layer (solib-svr4) learn about |
| 946 | this new process, relocate the cloned exec, pull in |
| 947 | shared libraries, and install the solib event breakpoint. |
| 948 | If a "cloned-VM" event was propagated better throughout |
| 949 | the core, this wouldn't be required. */ |
| 950 | solib_create_inferior_hook (0); |
| 951 | } |
| 952 | |
| 953 | /* Let the thread_db layer learn about this new process. */ |
| 954 | check_for_thread_db (); |
| 955 | } |
| 956 | |
| 957 | restore_child_signals_mask (&prev_mask); |
| 958 | return 0; |
| 959 | } |
| 960 | |
| 961 | \f |
| 962 | static int |
| 963 | linux_child_insert_fork_catchpoint (int pid) |
| 964 | { |
| 965 | return !linux_supports_tracefork (pid); |
| 966 | } |
| 967 | |
| 968 | static int |
| 969 | linux_child_remove_fork_catchpoint (int pid) |
| 970 | { |
| 971 | return 0; |
| 972 | } |
| 973 | |
| 974 | static int |
| 975 | linux_child_insert_vfork_catchpoint (int pid) |
| 976 | { |
| 977 | return !linux_supports_tracefork (pid); |
| 978 | } |
| 979 | |
| 980 | static int |
| 981 | linux_child_remove_vfork_catchpoint (int pid) |
| 982 | { |
| 983 | return 0; |
| 984 | } |
| 985 | |
| 986 | static int |
| 987 | linux_child_insert_exec_catchpoint (int pid) |
| 988 | { |
| 989 | return !linux_supports_tracefork (pid); |
| 990 | } |
| 991 | |
| 992 | static int |
| 993 | linux_child_remove_exec_catchpoint (int pid) |
| 994 | { |
| 995 | return 0; |
| 996 | } |
| 997 | |
| 998 | static int |
| 999 | linux_child_set_syscall_catchpoint (int pid, int needed, int any_count, |
| 1000 | int table_size, int *table) |
| 1001 | { |
| 1002 | if (!linux_supports_tracesysgood (pid)) |
| 1003 | return 1; |
| 1004 | |
| 1005 | /* On GNU/Linux, we ignore the arguments. It means that we only |
| 1006 | enable the syscall catchpoints, but do not disable them. |
| 1007 | |
| 1008 | Also, we do not use the `table' information because we do not |
| 1009 | filter system calls here. We let GDB do the logic for us. */ |
| 1010 | return 0; |
| 1011 | } |
| 1012 | |
| 1013 | /* On GNU/Linux there are no real LWP's. The closest thing to LWP's |
| 1014 | are processes sharing the same VM space. A multi-threaded process |
| 1015 | is basically a group of such processes. However, such a grouping |
| 1016 | is almost entirely a user-space issue; the kernel doesn't enforce |
| 1017 | such a grouping at all (this might change in the future). In |
| 1018 | general, we'll rely on the threads library (i.e. the GNU/Linux |
| 1019 | Threads library) to provide such a grouping. |
| 1020 | |
| 1021 | It is perfectly well possible to write a multi-threaded application |
| 1022 | without the assistance of a threads library, by using the clone |
| 1023 | system call directly. This module should be able to give some |
| 1024 | rudimentary support for debugging such applications if developers |
| 1025 | specify the CLONE_PTRACE flag in the clone system call, and are |
| 1026 | using the Linux kernel 2.4 or above. |
| 1027 | |
| 1028 | Note that there are some peculiarities in GNU/Linux that affect |
| 1029 | this code: |
| 1030 | |
| 1031 | - In general one should specify the __WCLONE flag to waitpid in |
| 1032 | order to make it report events for any of the cloned processes |
| 1033 | (and leave it out for the initial process). However, if a cloned |
| 1034 | process has exited the exit status is only reported if the |
| 1035 | __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but |
| 1036 | we cannot use it since GDB must work on older systems too. |
| 1037 | |
| 1038 | - When a traced, cloned process exits and is waited for by the |
| 1039 | debugger, the kernel reassigns it to the original parent and |
| 1040 | keeps it around as a "zombie". Somehow, the GNU/Linux Threads |
| 1041 | library doesn't notice this, which leads to the "zombie problem": |
| 1042 | When debugged a multi-threaded process that spawns a lot of |
| 1043 | threads will run out of processes, even if the threads exit, |
| 1044 | because the "zombies" stay around. */ |
| 1045 | |
| 1046 | /* List of known LWPs. */ |
| 1047 | struct lwp_info *lwp_list; |
| 1048 | \f |
| 1049 | |
| 1050 | /* Original signal mask. */ |
| 1051 | static sigset_t normal_mask; |
| 1052 | |
| 1053 | /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in |
| 1054 | _initialize_linux_nat. */ |
| 1055 | static sigset_t suspend_mask; |
| 1056 | |
| 1057 | /* Signals to block to make that sigsuspend work. */ |
| 1058 | static sigset_t blocked_mask; |
| 1059 | |
| 1060 | /* SIGCHLD action. */ |
| 1061 | struct sigaction sigchld_action; |
| 1062 | |
| 1063 | /* Block child signals (SIGCHLD and linux threads signals), and store |
| 1064 | the previous mask in PREV_MASK. */ |
| 1065 | |
| 1066 | static void |
| 1067 | block_child_signals (sigset_t *prev_mask) |
| 1068 | { |
| 1069 | /* Make sure SIGCHLD is blocked. */ |
| 1070 | if (!sigismember (&blocked_mask, SIGCHLD)) |
| 1071 | sigaddset (&blocked_mask, SIGCHLD); |
| 1072 | |
| 1073 | sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask); |
| 1074 | } |
| 1075 | |
| 1076 | /* Restore child signals mask, previously returned by |
| 1077 | block_child_signals. */ |
| 1078 | |
| 1079 | static void |
| 1080 | restore_child_signals_mask (sigset_t *prev_mask) |
| 1081 | { |
| 1082 | sigprocmask (SIG_SETMASK, prev_mask, NULL); |
| 1083 | } |
| 1084 | |
| 1085 | /* Mask of signals to pass directly to the inferior. */ |
| 1086 | static sigset_t pass_mask; |
| 1087 | |
| 1088 | /* Update signals to pass to the inferior. */ |
| 1089 | static void |
| 1090 | linux_nat_pass_signals (int numsigs, unsigned char *pass_signals) |
| 1091 | { |
| 1092 | int signo; |
| 1093 | |
| 1094 | sigemptyset (&pass_mask); |
| 1095 | |
| 1096 | for (signo = 1; signo < NSIG; signo++) |
| 1097 | { |
| 1098 | int target_signo = gdb_signal_from_host (signo); |
| 1099 | if (target_signo < numsigs && pass_signals[target_signo]) |
| 1100 | sigaddset (&pass_mask, signo); |
| 1101 | } |
| 1102 | } |
| 1103 | |
| 1104 | \f |
| 1105 | |
| 1106 | /* Prototypes for local functions. */ |
| 1107 | static int stop_wait_callback (struct lwp_info *lp, void *data); |
| 1108 | static int linux_thread_alive (ptid_t ptid); |
| 1109 | static char *linux_child_pid_to_exec_file (int pid); |
| 1110 | |
| 1111 | \f |
| 1112 | /* Convert wait status STATUS to a string. Used for printing debug |
| 1113 | messages only. */ |
| 1114 | |
| 1115 | static char * |
| 1116 | status_to_str (int status) |
| 1117 | { |
| 1118 | static char buf[64]; |
| 1119 | |
| 1120 | if (WIFSTOPPED (status)) |
| 1121 | { |
| 1122 | if (WSTOPSIG (status) == SYSCALL_SIGTRAP) |
| 1123 | snprintf (buf, sizeof (buf), "%s (stopped at syscall)", |
| 1124 | strsignal (SIGTRAP)); |
| 1125 | else |
| 1126 | snprintf (buf, sizeof (buf), "%s (stopped)", |
| 1127 | strsignal (WSTOPSIG (status))); |
| 1128 | } |
| 1129 | else if (WIFSIGNALED (status)) |
| 1130 | snprintf (buf, sizeof (buf), "%s (terminated)", |
| 1131 | strsignal (WTERMSIG (status))); |
| 1132 | else |
| 1133 | snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status)); |
| 1134 | |
| 1135 | return buf; |
| 1136 | } |
| 1137 | |
| 1138 | /* Destroy and free LP. */ |
| 1139 | |
| 1140 | static void |
| 1141 | lwp_free (struct lwp_info *lp) |
| 1142 | { |
| 1143 | xfree (lp->arch_private); |
| 1144 | xfree (lp); |
| 1145 | } |
| 1146 | |
| 1147 | /* Remove all LWPs belong to PID from the lwp list. */ |
| 1148 | |
| 1149 | static void |
| 1150 | purge_lwp_list (int pid) |
| 1151 | { |
| 1152 | struct lwp_info *lp, *lpprev, *lpnext; |
| 1153 | |
| 1154 | lpprev = NULL; |
| 1155 | |
| 1156 | for (lp = lwp_list; lp; lp = lpnext) |
| 1157 | { |
| 1158 | lpnext = lp->next; |
| 1159 | |
| 1160 | if (ptid_get_pid (lp->ptid) == pid) |
| 1161 | { |
| 1162 | if (lp == lwp_list) |
| 1163 | lwp_list = lp->next; |
| 1164 | else |
| 1165 | lpprev->next = lp->next; |
| 1166 | |
| 1167 | lwp_free (lp); |
| 1168 | } |
| 1169 | else |
| 1170 | lpprev = lp; |
| 1171 | } |
| 1172 | } |
| 1173 | |
| 1174 | /* Add the LWP specified by PID to the list. Return a pointer to the |
| 1175 | structure describing the new LWP. The LWP should already be stopped |
| 1176 | (with an exception for the very first LWP). */ |
| 1177 | |
| 1178 | static struct lwp_info * |
| 1179 | add_lwp (ptid_t ptid) |
| 1180 | { |
| 1181 | struct lwp_info *lp; |
| 1182 | |
| 1183 | gdb_assert (is_lwp (ptid)); |
| 1184 | |
| 1185 | lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info)); |
| 1186 | |
| 1187 | memset (lp, 0, sizeof (struct lwp_info)); |
| 1188 | |
| 1189 | lp->last_resume_kind = resume_continue; |
| 1190 | lp->waitstatus.kind = TARGET_WAITKIND_IGNORE; |
| 1191 | |
| 1192 | lp->ptid = ptid; |
| 1193 | lp->core = -1; |
| 1194 | |
| 1195 | lp->next = lwp_list; |
| 1196 | lwp_list = lp; |
| 1197 | |
| 1198 | /* Let the arch specific bits know about this new thread. Current |
| 1199 | clients of this callback take the opportunity to install |
| 1200 | watchpoints in the new thread. Don't do this for the first |
| 1201 | thread though. If we're spawning a child ("run"), the thread |
| 1202 | executes the shell wrapper first, and we shouldn't touch it until |
| 1203 | it execs the program we want to debug. For "attach", it'd be |
| 1204 | okay to call the callback, but it's not necessary, because |
| 1205 | watchpoints can't yet have been inserted into the inferior. */ |
| 1206 | if (num_lwps (GET_PID (ptid)) > 1 && linux_nat_new_thread != NULL) |
| 1207 | linux_nat_new_thread (lp); |
| 1208 | |
| 1209 | return lp; |
| 1210 | } |
| 1211 | |
| 1212 | /* Remove the LWP specified by PID from the list. */ |
| 1213 | |
| 1214 | static void |
| 1215 | delete_lwp (ptid_t ptid) |
| 1216 | { |
| 1217 | struct lwp_info *lp, *lpprev; |
| 1218 | |
| 1219 | lpprev = NULL; |
| 1220 | |
| 1221 | for (lp = lwp_list; lp; lpprev = lp, lp = lp->next) |
| 1222 | if (ptid_equal (lp->ptid, ptid)) |
| 1223 | break; |
| 1224 | |
| 1225 | if (!lp) |
| 1226 | return; |
| 1227 | |
| 1228 | if (lpprev) |
| 1229 | lpprev->next = lp->next; |
| 1230 | else |
| 1231 | lwp_list = lp->next; |
| 1232 | |
| 1233 | lwp_free (lp); |
| 1234 | } |
| 1235 | |
| 1236 | /* Return a pointer to the structure describing the LWP corresponding |
| 1237 | to PID. If no corresponding LWP could be found, return NULL. */ |
| 1238 | |
| 1239 | static struct lwp_info * |
| 1240 | find_lwp_pid (ptid_t ptid) |
| 1241 | { |
| 1242 | struct lwp_info *lp; |
| 1243 | int lwp; |
| 1244 | |
| 1245 | if (is_lwp (ptid)) |
| 1246 | lwp = GET_LWP (ptid); |
| 1247 | else |
| 1248 | lwp = GET_PID (ptid); |
| 1249 | |
| 1250 | for (lp = lwp_list; lp; lp = lp->next) |
| 1251 | if (lwp == GET_LWP (lp->ptid)) |
| 1252 | return lp; |
| 1253 | |
| 1254 | return NULL; |
| 1255 | } |
| 1256 | |
| 1257 | /* Call CALLBACK with its second argument set to DATA for every LWP in |
| 1258 | the list. If CALLBACK returns 1 for a particular LWP, return a |
| 1259 | pointer to the structure describing that LWP immediately. |
| 1260 | Otherwise return NULL. */ |
| 1261 | |
| 1262 | struct lwp_info * |
| 1263 | iterate_over_lwps (ptid_t filter, |
| 1264 | int (*callback) (struct lwp_info *, void *), |
| 1265 | void *data) |
| 1266 | { |
| 1267 | struct lwp_info *lp, *lpnext; |
| 1268 | |
| 1269 | for (lp = lwp_list; lp; lp = lpnext) |
| 1270 | { |
| 1271 | lpnext = lp->next; |
| 1272 | |
| 1273 | if (ptid_match (lp->ptid, filter)) |
| 1274 | { |
| 1275 | if ((*callback) (lp, data)) |
| 1276 | return lp; |
| 1277 | } |
| 1278 | } |
| 1279 | |
| 1280 | return NULL; |
| 1281 | } |
| 1282 | |
| 1283 | /* Iterate like iterate_over_lwps does except when forking-off a child call |
| 1284 | CALLBACK with CALLBACK_DATA specifically only for that new child PID. */ |
| 1285 | |
| 1286 | void |
| 1287 | linux_nat_iterate_watchpoint_lwps |
| 1288 | (linux_nat_iterate_watchpoint_lwps_ftype callback, void *callback_data) |
| 1289 | { |
| 1290 | int inferior_pid = ptid_get_pid (inferior_ptid); |
| 1291 | struct inferior *inf = current_inferior (); |
| 1292 | |
| 1293 | if (inf->pid == inferior_pid) |
| 1294 | { |
| 1295 | /* Iterate all the threads of the current inferior. Without specifying |
| 1296 | INFERIOR_PID it would iterate all threads of all inferiors, which is |
| 1297 | inappropriate for watchpoints. */ |
| 1298 | |
| 1299 | iterate_over_lwps (pid_to_ptid (inferior_pid), callback, callback_data); |
| 1300 | } |
| 1301 | else |
| 1302 | { |
| 1303 | /* Detaching a new child PID temporarily present in INFERIOR_PID. */ |
| 1304 | |
| 1305 | struct lwp_info *child_lp; |
| 1306 | struct cleanup *old_chain; |
| 1307 | pid_t child_pid = GET_PID (inferior_ptid); |
| 1308 | ptid_t child_ptid = ptid_build (child_pid, child_pid, 0); |
| 1309 | |
| 1310 | gdb_assert (!is_lwp (inferior_ptid)); |
| 1311 | gdb_assert (find_lwp_pid (child_ptid) == NULL); |
| 1312 | child_lp = add_lwp (child_ptid); |
| 1313 | child_lp->stopped = 1; |
| 1314 | child_lp->last_resume_kind = resume_stop; |
| 1315 | old_chain = make_cleanup (delete_lwp_cleanup, child_lp); |
| 1316 | |
| 1317 | callback (child_lp, callback_data); |
| 1318 | |
| 1319 | do_cleanups (old_chain); |
| 1320 | } |
| 1321 | } |
| 1322 | |
| 1323 | /* Update our internal state when changing from one checkpoint to |
| 1324 | another indicated by NEW_PTID. We can only switch single-threaded |
| 1325 | applications, so we only create one new LWP, and the previous list |
| 1326 | is discarded. */ |
| 1327 | |
| 1328 | void |
| 1329 | linux_nat_switch_fork (ptid_t new_ptid) |
| 1330 | { |
| 1331 | struct lwp_info *lp; |
| 1332 | |
| 1333 | purge_lwp_list (GET_PID (inferior_ptid)); |
| 1334 | |
| 1335 | lp = add_lwp (new_ptid); |
| 1336 | lp->stopped = 1; |
| 1337 | |
| 1338 | /* This changes the thread's ptid while preserving the gdb thread |
| 1339 | num. Also changes the inferior pid, while preserving the |
| 1340 | inferior num. */ |
| 1341 | thread_change_ptid (inferior_ptid, new_ptid); |
| 1342 | |
| 1343 | /* We've just told GDB core that the thread changed target id, but, |
| 1344 | in fact, it really is a different thread, with different register |
| 1345 | contents. */ |
| 1346 | registers_changed (); |
| 1347 | } |
| 1348 | |
| 1349 | /* Handle the exit of a single thread LP. */ |
| 1350 | |
| 1351 | static void |
| 1352 | exit_lwp (struct lwp_info *lp) |
| 1353 | { |
| 1354 | struct thread_info *th = find_thread_ptid (lp->ptid); |
| 1355 | |
| 1356 | if (th) |
| 1357 | { |
| 1358 | if (print_thread_events) |
| 1359 | printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid)); |
| 1360 | |
| 1361 | delete_thread (lp->ptid); |
| 1362 | } |
| 1363 | |
| 1364 | delete_lwp (lp->ptid); |
| 1365 | } |
| 1366 | |
| 1367 | /* Wait for the LWP specified by LP, which we have just attached to. |
| 1368 | Returns a wait status for that LWP, to cache. */ |
| 1369 | |
| 1370 | static int |
| 1371 | linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned, |
| 1372 | int *signalled) |
| 1373 | { |
| 1374 | pid_t new_pid, pid = GET_LWP (ptid); |
| 1375 | int status; |
| 1376 | |
| 1377 | if (linux_proc_pid_is_stopped (pid)) |
| 1378 | { |
| 1379 | if (debug_linux_nat) |
| 1380 | fprintf_unfiltered (gdb_stdlog, |
| 1381 | "LNPAW: Attaching to a stopped process\n"); |
| 1382 | |
| 1383 | /* The process is definitely stopped. It is in a job control |
| 1384 | stop, unless the kernel predates the TASK_STOPPED / |
| 1385 | TASK_TRACED distinction, in which case it might be in a |
| 1386 | ptrace stop. Make sure it is in a ptrace stop; from there we |
| 1387 | can kill it, signal it, et cetera. |
| 1388 | |
| 1389 | First make sure there is a pending SIGSTOP. Since we are |
| 1390 | already attached, the process can not transition from stopped |
| 1391 | to running without a PTRACE_CONT; so we know this signal will |
| 1392 | go into the queue. The SIGSTOP generated by PTRACE_ATTACH is |
| 1393 | probably already in the queue (unless this kernel is old |
| 1394 | enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP |
| 1395 | is not an RT signal, it can only be queued once. */ |
| 1396 | kill_lwp (pid, SIGSTOP); |
| 1397 | |
| 1398 | /* Finally, resume the stopped process. This will deliver the SIGSTOP |
| 1399 | (or a higher priority signal, just like normal PTRACE_ATTACH). */ |
| 1400 | ptrace (PTRACE_CONT, pid, 0, 0); |
| 1401 | } |
| 1402 | |
| 1403 | /* Make sure the initial process is stopped. The user-level threads |
| 1404 | layer might want to poke around in the inferior, and that won't |
| 1405 | work if things haven't stabilized yet. */ |
| 1406 | new_pid = my_waitpid (pid, &status, 0); |
| 1407 | if (new_pid == -1 && errno == ECHILD) |
| 1408 | { |
| 1409 | if (first) |
| 1410 | warning (_("%s is a cloned process"), target_pid_to_str (ptid)); |
| 1411 | |
| 1412 | /* Try again with __WCLONE to check cloned processes. */ |
| 1413 | new_pid = my_waitpid (pid, &status, __WCLONE); |
| 1414 | *cloned = 1; |
| 1415 | } |
| 1416 | |
| 1417 | gdb_assert (pid == new_pid); |
| 1418 | |
| 1419 | if (!WIFSTOPPED (status)) |
| 1420 | { |
| 1421 | /* The pid we tried to attach has apparently just exited. */ |
| 1422 | if (debug_linux_nat) |
| 1423 | fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s", |
| 1424 | pid, status_to_str (status)); |
| 1425 | return status; |
| 1426 | } |
| 1427 | |
| 1428 | if (WSTOPSIG (status) != SIGSTOP) |
| 1429 | { |
| 1430 | *signalled = 1; |
| 1431 | if (debug_linux_nat) |
| 1432 | fprintf_unfiltered (gdb_stdlog, |
| 1433 | "LNPAW: Received %s after attaching\n", |
| 1434 | status_to_str (status)); |
| 1435 | } |
| 1436 | |
| 1437 | return status; |
| 1438 | } |
| 1439 | |
| 1440 | /* Attach to the LWP specified by PID. Return 0 if successful, -1 if |
| 1441 | the new LWP could not be attached, or 1 if we're already auto |
| 1442 | attached to this thread, but haven't processed the |
| 1443 | PTRACE_EVENT_CLONE event of its parent thread, so we just ignore |
| 1444 | its existance, without considering it an error. */ |
| 1445 | |
| 1446 | int |
| 1447 | lin_lwp_attach_lwp (ptid_t ptid) |
| 1448 | { |
| 1449 | struct lwp_info *lp; |
| 1450 | sigset_t prev_mask; |
| 1451 | int lwpid; |
| 1452 | |
| 1453 | gdb_assert (is_lwp (ptid)); |
| 1454 | |
| 1455 | block_child_signals (&prev_mask); |
| 1456 | |
| 1457 | lp = find_lwp_pid (ptid); |
| 1458 | lwpid = GET_LWP (ptid); |
| 1459 | |
| 1460 | /* We assume that we're already attached to any LWP that has an id |
| 1461 | equal to the overall process id, and to any LWP that is already |
| 1462 | in our list of LWPs. If we're not seeing exit events from threads |
| 1463 | and we've had PID wraparound since we last tried to stop all threads, |
| 1464 | this assumption might be wrong; fortunately, this is very unlikely |
| 1465 | to happen. */ |
| 1466 | if (lwpid != GET_PID (ptid) && lp == NULL) |
| 1467 | { |
| 1468 | int status, cloned = 0, signalled = 0; |
| 1469 | |
| 1470 | if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0) |
| 1471 | { |
| 1472 | if (linux_supports_tracefork_flag) |
| 1473 | { |
| 1474 | /* If we haven't stopped all threads when we get here, |
| 1475 | we may have seen a thread listed in thread_db's list, |
| 1476 | but not processed the PTRACE_EVENT_CLONE yet. If |
| 1477 | that's the case, ignore this new thread, and let |
| 1478 | normal event handling discover it later. */ |
| 1479 | if (in_pid_list_p (stopped_pids, lwpid)) |
| 1480 | { |
| 1481 | /* We've already seen this thread stop, but we |
| 1482 | haven't seen the PTRACE_EVENT_CLONE extended |
| 1483 | event yet. */ |
| 1484 | restore_child_signals_mask (&prev_mask); |
| 1485 | return 0; |
| 1486 | } |
| 1487 | else |
| 1488 | { |
| 1489 | int new_pid; |
| 1490 | int status; |
| 1491 | |
| 1492 | /* See if we've got a stop for this new child |
| 1493 | pending. If so, we're already attached. */ |
| 1494 | new_pid = my_waitpid (lwpid, &status, WNOHANG); |
| 1495 | if (new_pid == -1 && errno == ECHILD) |
| 1496 | new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG); |
| 1497 | if (new_pid != -1) |
| 1498 | { |
| 1499 | if (WIFSTOPPED (status)) |
| 1500 | add_to_pid_list (&stopped_pids, lwpid, status); |
| 1501 | |
| 1502 | restore_child_signals_mask (&prev_mask); |
| 1503 | return 1; |
| 1504 | } |
| 1505 | } |
| 1506 | } |
| 1507 | |
| 1508 | /* If we fail to attach to the thread, issue a warning, |
| 1509 | but continue. One way this can happen is if thread |
| 1510 | creation is interrupted; as of Linux kernel 2.6.19, a |
| 1511 | bug may place threads in the thread list and then fail |
| 1512 | to create them. */ |
| 1513 | warning (_("Can't attach %s: %s"), target_pid_to_str (ptid), |
| 1514 | safe_strerror (errno)); |
| 1515 | restore_child_signals_mask (&prev_mask); |
| 1516 | return -1; |
| 1517 | } |
| 1518 | |
| 1519 | if (debug_linux_nat) |
| 1520 | fprintf_unfiltered (gdb_stdlog, |
| 1521 | "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n", |
| 1522 | target_pid_to_str (ptid)); |
| 1523 | |
| 1524 | status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled); |
| 1525 | if (!WIFSTOPPED (status)) |
| 1526 | { |
| 1527 | restore_child_signals_mask (&prev_mask); |
| 1528 | return 1; |
| 1529 | } |
| 1530 | |
| 1531 | lp = add_lwp (ptid); |
| 1532 | lp->stopped = 1; |
| 1533 | lp->cloned = cloned; |
| 1534 | lp->signalled = signalled; |
| 1535 | if (WSTOPSIG (status) != SIGSTOP) |
| 1536 | { |
| 1537 | lp->resumed = 1; |
| 1538 | lp->status = status; |
| 1539 | } |
| 1540 | |
| 1541 | target_post_attach (GET_LWP (lp->ptid)); |
| 1542 | |
| 1543 | if (debug_linux_nat) |
| 1544 | { |
| 1545 | fprintf_unfiltered (gdb_stdlog, |
| 1546 | "LLAL: waitpid %s received %s\n", |
| 1547 | target_pid_to_str (ptid), |
| 1548 | status_to_str (status)); |
| 1549 | } |
| 1550 | } |
| 1551 | else |
| 1552 | { |
| 1553 | /* We assume that the LWP representing the original process is |
| 1554 | already stopped. Mark it as stopped in the data structure |
| 1555 | that the GNU/linux ptrace layer uses to keep track of |
| 1556 | threads. Note that this won't have already been done since |
| 1557 | the main thread will have, we assume, been stopped by an |
| 1558 | attach from a different layer. */ |
| 1559 | if (lp == NULL) |
| 1560 | lp = add_lwp (ptid); |
| 1561 | lp->stopped = 1; |
| 1562 | } |
| 1563 | |
| 1564 | lp->last_resume_kind = resume_stop; |
| 1565 | restore_child_signals_mask (&prev_mask); |
| 1566 | return 0; |
| 1567 | } |
| 1568 | |
| 1569 | static void |
| 1570 | linux_nat_create_inferior (struct target_ops *ops, |
| 1571 | char *exec_file, char *allargs, char **env, |
| 1572 | int from_tty) |
| 1573 | { |
| 1574 | #ifdef HAVE_PERSONALITY |
| 1575 | int personality_orig = 0, personality_set = 0; |
| 1576 | #endif /* HAVE_PERSONALITY */ |
| 1577 | |
| 1578 | /* The fork_child mechanism is synchronous and calls target_wait, so |
| 1579 | we have to mask the async mode. */ |
| 1580 | |
| 1581 | #ifdef HAVE_PERSONALITY |
| 1582 | if (disable_randomization) |
| 1583 | { |
| 1584 | errno = 0; |
| 1585 | personality_orig = personality (0xffffffff); |
| 1586 | if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE)) |
| 1587 | { |
| 1588 | personality_set = 1; |
| 1589 | personality (personality_orig | ADDR_NO_RANDOMIZE); |
| 1590 | } |
| 1591 | if (errno != 0 || (personality_set |
| 1592 | && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE))) |
| 1593 | warning (_("Error disabling address space randomization: %s"), |
| 1594 | safe_strerror (errno)); |
| 1595 | } |
| 1596 | #endif /* HAVE_PERSONALITY */ |
| 1597 | |
| 1598 | /* Make sure we report all signals during startup. */ |
| 1599 | linux_nat_pass_signals (0, NULL); |
| 1600 | |
| 1601 | linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty); |
| 1602 | |
| 1603 | #ifdef HAVE_PERSONALITY |
| 1604 | if (personality_set) |
| 1605 | { |
| 1606 | errno = 0; |
| 1607 | personality (personality_orig); |
| 1608 | if (errno != 0) |
| 1609 | warning (_("Error restoring address space randomization: %s"), |
| 1610 | safe_strerror (errno)); |
| 1611 | } |
| 1612 | #endif /* HAVE_PERSONALITY */ |
| 1613 | } |
| 1614 | |
| 1615 | static void |
| 1616 | linux_nat_attach (struct target_ops *ops, char *args, int from_tty) |
| 1617 | { |
| 1618 | struct lwp_info *lp; |
| 1619 | int status; |
| 1620 | ptid_t ptid; |
| 1621 | volatile struct gdb_exception ex; |
| 1622 | |
| 1623 | /* Make sure we report all signals during attach. */ |
| 1624 | linux_nat_pass_signals (0, NULL); |
| 1625 | |
| 1626 | TRY_CATCH (ex, RETURN_MASK_ERROR) |
| 1627 | { |
| 1628 | linux_ops->to_attach (ops, args, from_tty); |
| 1629 | } |
| 1630 | if (ex.reason < 0) |
| 1631 | { |
| 1632 | pid_t pid = parse_pid_to_attach (args); |
| 1633 | struct buffer buffer; |
| 1634 | char *message, *buffer_s; |
| 1635 | |
| 1636 | message = xstrdup (ex.message); |
| 1637 | make_cleanup (xfree, message); |
| 1638 | |
| 1639 | buffer_init (&buffer); |
| 1640 | linux_ptrace_attach_warnings (pid, &buffer); |
| 1641 | |
| 1642 | buffer_grow_str0 (&buffer, ""); |
| 1643 | buffer_s = buffer_finish (&buffer); |
| 1644 | make_cleanup (xfree, buffer_s); |
| 1645 | |
| 1646 | throw_error (ex.error, "%s%s", buffer_s, message); |
| 1647 | } |
| 1648 | |
| 1649 | /* The ptrace base target adds the main thread with (pid,0,0) |
| 1650 | format. Decorate it with lwp info. */ |
| 1651 | ptid = BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid)); |
| 1652 | thread_change_ptid (inferior_ptid, ptid); |
| 1653 | |
| 1654 | /* Add the initial process as the first LWP to the list. */ |
| 1655 | lp = add_lwp (ptid); |
| 1656 | |
| 1657 | status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned, |
| 1658 | &lp->signalled); |
| 1659 | if (!WIFSTOPPED (status)) |
| 1660 | { |
| 1661 | if (WIFEXITED (status)) |
| 1662 | { |
| 1663 | int exit_code = WEXITSTATUS (status); |
| 1664 | |
| 1665 | target_terminal_ours (); |
| 1666 | target_mourn_inferior (); |
| 1667 | if (exit_code == 0) |
| 1668 | error (_("Unable to attach: program exited normally.")); |
| 1669 | else |
| 1670 | error (_("Unable to attach: program exited with code %d."), |
| 1671 | exit_code); |
| 1672 | } |
| 1673 | else if (WIFSIGNALED (status)) |
| 1674 | { |
| 1675 | enum gdb_signal signo; |
| 1676 | |
| 1677 | target_terminal_ours (); |
| 1678 | target_mourn_inferior (); |
| 1679 | |
| 1680 | signo = gdb_signal_from_host (WTERMSIG (status)); |
| 1681 | error (_("Unable to attach: program terminated with signal " |
| 1682 | "%s, %s."), |
| 1683 | gdb_signal_to_name (signo), |
| 1684 | gdb_signal_to_string (signo)); |
| 1685 | } |
| 1686 | |
| 1687 | internal_error (__FILE__, __LINE__, |
| 1688 | _("unexpected status %d for PID %ld"), |
| 1689 | status, (long) GET_LWP (ptid)); |
| 1690 | } |
| 1691 | |
| 1692 | lp->stopped = 1; |
| 1693 | |
| 1694 | /* Save the wait status to report later. */ |
| 1695 | lp->resumed = 1; |
| 1696 | if (debug_linux_nat) |
| 1697 | fprintf_unfiltered (gdb_stdlog, |
| 1698 | "LNA: waitpid %ld, saving status %s\n", |
| 1699 | (long) GET_PID (lp->ptid), status_to_str (status)); |
| 1700 | |
| 1701 | lp->status = status; |
| 1702 | |
| 1703 | if (target_can_async_p ()) |
| 1704 | target_async (inferior_event_handler, 0); |
| 1705 | } |
| 1706 | |
| 1707 | /* Get pending status of LP. */ |
| 1708 | static int |
| 1709 | get_pending_status (struct lwp_info *lp, int *status) |
| 1710 | { |
| 1711 | enum gdb_signal signo = GDB_SIGNAL_0; |
| 1712 | |
| 1713 | /* If we paused threads momentarily, we may have stored pending |
| 1714 | events in lp->status or lp->waitstatus (see stop_wait_callback), |
| 1715 | and GDB core hasn't seen any signal for those threads. |
| 1716 | Otherwise, the last signal reported to the core is found in the |
| 1717 | thread object's stop_signal. |
| 1718 | |
| 1719 | There's a corner case that isn't handled here at present. Only |
| 1720 | if the thread stopped with a TARGET_WAITKIND_STOPPED does |
| 1721 | stop_signal make sense as a real signal to pass to the inferior. |
| 1722 | Some catchpoint related events, like |
| 1723 | TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set |
| 1724 | to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But, |
| 1725 | those traps are debug API (ptrace in our case) related and |
| 1726 | induced; the inferior wouldn't see them if it wasn't being |
| 1727 | traced. Hence, we should never pass them to the inferior, even |
| 1728 | when set to pass state. Since this corner case isn't handled by |
| 1729 | infrun.c when proceeding with a signal, for consistency, neither |
| 1730 | do we handle it here (or elsewhere in the file we check for |
| 1731 | signal pass state). Normally SIGTRAP isn't set to pass state, so |
| 1732 | this is really a corner case. */ |
| 1733 | |
| 1734 | if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE) |
| 1735 | signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */ |
| 1736 | else if (lp->status) |
| 1737 | signo = gdb_signal_from_host (WSTOPSIG (lp->status)); |
| 1738 | else if (non_stop && !is_executing (lp->ptid)) |
| 1739 | { |
| 1740 | struct thread_info *tp = find_thread_ptid (lp->ptid); |
| 1741 | |
| 1742 | signo = tp->suspend.stop_signal; |
| 1743 | } |
| 1744 | else if (!non_stop) |
| 1745 | { |
| 1746 | struct target_waitstatus last; |
| 1747 | ptid_t last_ptid; |
| 1748 | |
| 1749 | get_last_target_status (&last_ptid, &last); |
| 1750 | |
| 1751 | if (GET_LWP (lp->ptid) == GET_LWP (last_ptid)) |
| 1752 | { |
| 1753 | struct thread_info *tp = find_thread_ptid (lp->ptid); |
| 1754 | |
| 1755 | signo = tp->suspend.stop_signal; |
| 1756 | } |
| 1757 | } |
| 1758 | |
| 1759 | *status = 0; |
| 1760 | |
| 1761 | if (signo == GDB_SIGNAL_0) |
| 1762 | { |
| 1763 | if (debug_linux_nat) |
| 1764 | fprintf_unfiltered (gdb_stdlog, |
| 1765 | "GPT: lwp %s has no pending signal\n", |
| 1766 | target_pid_to_str (lp->ptid)); |
| 1767 | } |
| 1768 | else if (!signal_pass_state (signo)) |
| 1769 | { |
| 1770 | if (debug_linux_nat) |
| 1771 | fprintf_unfiltered (gdb_stdlog, |
| 1772 | "GPT: lwp %s had signal %s, " |
| 1773 | "but it is in no pass state\n", |
| 1774 | target_pid_to_str (lp->ptid), |
| 1775 | gdb_signal_to_string (signo)); |
| 1776 | } |
| 1777 | else |
| 1778 | { |
| 1779 | *status = W_STOPCODE (gdb_signal_to_host (signo)); |
| 1780 | |
| 1781 | if (debug_linux_nat) |
| 1782 | fprintf_unfiltered (gdb_stdlog, |
| 1783 | "GPT: lwp %s has pending signal %s\n", |
| 1784 | target_pid_to_str (lp->ptid), |
| 1785 | gdb_signal_to_string (signo)); |
| 1786 | } |
| 1787 | |
| 1788 | return 0; |
| 1789 | } |
| 1790 | |
| 1791 | static int |
| 1792 | detach_callback (struct lwp_info *lp, void *data) |
| 1793 | { |
| 1794 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); |
| 1795 | |
| 1796 | if (debug_linux_nat && lp->status) |
| 1797 | fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n", |
| 1798 | strsignal (WSTOPSIG (lp->status)), |
| 1799 | target_pid_to_str (lp->ptid)); |
| 1800 | |
| 1801 | /* If there is a pending SIGSTOP, get rid of it. */ |
| 1802 | if (lp->signalled) |
| 1803 | { |
| 1804 | if (debug_linux_nat) |
| 1805 | fprintf_unfiltered (gdb_stdlog, |
| 1806 | "DC: Sending SIGCONT to %s\n", |
| 1807 | target_pid_to_str (lp->ptid)); |
| 1808 | |
| 1809 | kill_lwp (GET_LWP (lp->ptid), SIGCONT); |
| 1810 | lp->signalled = 0; |
| 1811 | } |
| 1812 | |
| 1813 | /* We don't actually detach from the LWP that has an id equal to the |
| 1814 | overall process id just yet. */ |
| 1815 | if (GET_LWP (lp->ptid) != GET_PID (lp->ptid)) |
| 1816 | { |
| 1817 | int status = 0; |
| 1818 | |
| 1819 | /* Pass on any pending signal for this LWP. */ |
| 1820 | get_pending_status (lp, &status); |
| 1821 | |
| 1822 | if (linux_nat_prepare_to_resume != NULL) |
| 1823 | linux_nat_prepare_to_resume (lp); |
| 1824 | errno = 0; |
| 1825 | if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0, |
| 1826 | WSTOPSIG (status)) < 0) |
| 1827 | error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid), |
| 1828 | safe_strerror (errno)); |
| 1829 | |
| 1830 | if (debug_linux_nat) |
| 1831 | fprintf_unfiltered (gdb_stdlog, |
| 1832 | "PTRACE_DETACH (%s, %s, 0) (OK)\n", |
| 1833 | target_pid_to_str (lp->ptid), |
| 1834 | strsignal (WSTOPSIG (status))); |
| 1835 | |
| 1836 | delete_lwp (lp->ptid); |
| 1837 | } |
| 1838 | |
| 1839 | return 0; |
| 1840 | } |
| 1841 | |
| 1842 | static void |
| 1843 | linux_nat_detach (struct target_ops *ops, char *args, int from_tty) |
| 1844 | { |
| 1845 | int pid; |
| 1846 | int status; |
| 1847 | struct lwp_info *main_lwp; |
| 1848 | |
| 1849 | pid = GET_PID (inferior_ptid); |
| 1850 | |
| 1851 | /* Don't unregister from the event loop, as there may be other |
| 1852 | inferiors running. */ |
| 1853 | |
| 1854 | /* Stop all threads before detaching. ptrace requires that the |
| 1855 | thread is stopped to sucessfully detach. */ |
| 1856 | iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL); |
| 1857 | /* ... and wait until all of them have reported back that |
| 1858 | they're no longer running. */ |
| 1859 | iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL); |
| 1860 | |
| 1861 | iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL); |
| 1862 | |
| 1863 | /* Only the initial process should be left right now. */ |
| 1864 | gdb_assert (num_lwps (GET_PID (inferior_ptid)) == 1); |
| 1865 | |
| 1866 | main_lwp = find_lwp_pid (pid_to_ptid (pid)); |
| 1867 | |
| 1868 | /* Pass on any pending signal for the last LWP. */ |
| 1869 | if ((args == NULL || *args == '\0') |
| 1870 | && get_pending_status (main_lwp, &status) != -1 |
| 1871 | && WIFSTOPPED (status)) |
| 1872 | { |
| 1873 | /* Put the signal number in ARGS so that inf_ptrace_detach will |
| 1874 | pass it along with PTRACE_DETACH. */ |
| 1875 | args = alloca (8); |
| 1876 | sprintf (args, "%d", (int) WSTOPSIG (status)); |
| 1877 | if (debug_linux_nat) |
| 1878 | fprintf_unfiltered (gdb_stdlog, |
| 1879 | "LND: Sending signal %s to %s\n", |
| 1880 | args, |
| 1881 | target_pid_to_str (main_lwp->ptid)); |
| 1882 | } |
| 1883 | |
| 1884 | if (linux_nat_prepare_to_resume != NULL) |
| 1885 | linux_nat_prepare_to_resume (main_lwp); |
| 1886 | delete_lwp (main_lwp->ptid); |
| 1887 | |
| 1888 | if (forks_exist_p ()) |
| 1889 | { |
| 1890 | /* Multi-fork case. The current inferior_ptid is being detached |
| 1891 | from, but there are other viable forks to debug. Detach from |
| 1892 | the current fork, and context-switch to the first |
| 1893 | available. */ |
| 1894 | linux_fork_detach (args, from_tty); |
| 1895 | } |
| 1896 | else |
| 1897 | linux_ops->to_detach (ops, args, from_tty); |
| 1898 | } |
| 1899 | |
| 1900 | /* Resume LP. */ |
| 1901 | |
| 1902 | static void |
| 1903 | resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo) |
| 1904 | { |
| 1905 | if (lp->stopped) |
| 1906 | { |
| 1907 | struct inferior *inf = find_inferior_pid (GET_PID (lp->ptid)); |
| 1908 | |
| 1909 | if (inf->vfork_child != NULL) |
| 1910 | { |
| 1911 | if (debug_linux_nat) |
| 1912 | fprintf_unfiltered (gdb_stdlog, |
| 1913 | "RC: Not resuming %s (vfork parent)\n", |
| 1914 | target_pid_to_str (lp->ptid)); |
| 1915 | } |
| 1916 | else if (lp->status == 0 |
| 1917 | && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE) |
| 1918 | { |
| 1919 | if (debug_linux_nat) |
| 1920 | fprintf_unfiltered (gdb_stdlog, |
| 1921 | "RC: Resuming sibling %s, %s, %s\n", |
| 1922 | target_pid_to_str (lp->ptid), |
| 1923 | (signo != GDB_SIGNAL_0 |
| 1924 | ? strsignal (gdb_signal_to_host (signo)) |
| 1925 | : "0"), |
| 1926 | step ? "step" : "resume"); |
| 1927 | |
| 1928 | if (linux_nat_prepare_to_resume != NULL) |
| 1929 | linux_nat_prepare_to_resume (lp); |
| 1930 | linux_ops->to_resume (linux_ops, |
| 1931 | pid_to_ptid (GET_LWP (lp->ptid)), |
| 1932 | step, signo); |
| 1933 | lp->stopped = 0; |
| 1934 | lp->step = step; |
| 1935 | lp->stopped_by_watchpoint = 0; |
| 1936 | } |
| 1937 | else |
| 1938 | { |
| 1939 | if (debug_linux_nat) |
| 1940 | fprintf_unfiltered (gdb_stdlog, |
| 1941 | "RC: Not resuming sibling %s (has pending)\n", |
| 1942 | target_pid_to_str (lp->ptid)); |
| 1943 | } |
| 1944 | } |
| 1945 | else |
| 1946 | { |
| 1947 | if (debug_linux_nat) |
| 1948 | fprintf_unfiltered (gdb_stdlog, |
| 1949 | "RC: Not resuming sibling %s (not stopped)\n", |
| 1950 | target_pid_to_str (lp->ptid)); |
| 1951 | } |
| 1952 | } |
| 1953 | |
| 1954 | /* Resume LWP, with the last stop signal, if it is in pass state. */ |
| 1955 | |
| 1956 | static int |
| 1957 | linux_nat_resume_callback (struct lwp_info *lp, void *data) |
| 1958 | { |
| 1959 | enum gdb_signal signo = GDB_SIGNAL_0; |
| 1960 | |
| 1961 | if (lp->stopped) |
| 1962 | { |
| 1963 | struct thread_info *thread; |
| 1964 | |
| 1965 | thread = find_thread_ptid (lp->ptid); |
| 1966 | if (thread != NULL) |
| 1967 | { |
| 1968 | if (signal_pass_state (thread->suspend.stop_signal)) |
| 1969 | signo = thread->suspend.stop_signal; |
| 1970 | thread->suspend.stop_signal = GDB_SIGNAL_0; |
| 1971 | } |
| 1972 | } |
| 1973 | |
| 1974 | resume_lwp (lp, 0, signo); |
| 1975 | return 0; |
| 1976 | } |
| 1977 | |
| 1978 | static int |
| 1979 | resume_clear_callback (struct lwp_info *lp, void *data) |
| 1980 | { |
| 1981 | lp->resumed = 0; |
| 1982 | lp->last_resume_kind = resume_stop; |
| 1983 | return 0; |
| 1984 | } |
| 1985 | |
| 1986 | static int |
| 1987 | resume_set_callback (struct lwp_info *lp, void *data) |
| 1988 | { |
| 1989 | lp->resumed = 1; |
| 1990 | lp->last_resume_kind = resume_continue; |
| 1991 | return 0; |
| 1992 | } |
| 1993 | |
| 1994 | static void |
| 1995 | linux_nat_resume (struct target_ops *ops, |
| 1996 | ptid_t ptid, int step, enum gdb_signal signo) |
| 1997 | { |
| 1998 | sigset_t prev_mask; |
| 1999 | struct lwp_info *lp; |
| 2000 | int resume_many; |
| 2001 | |
| 2002 | if (debug_linux_nat) |
| 2003 | fprintf_unfiltered (gdb_stdlog, |
| 2004 | "LLR: Preparing to %s %s, %s, inferior_ptid %s\n", |
| 2005 | step ? "step" : "resume", |
| 2006 | target_pid_to_str (ptid), |
| 2007 | (signo != GDB_SIGNAL_0 |
| 2008 | ? strsignal (gdb_signal_to_host (signo)) : "0"), |
| 2009 | target_pid_to_str (inferior_ptid)); |
| 2010 | |
| 2011 | block_child_signals (&prev_mask); |
| 2012 | |
| 2013 | /* A specific PTID means `step only this process id'. */ |
| 2014 | resume_many = (ptid_equal (minus_one_ptid, ptid) |
| 2015 | || ptid_is_pid (ptid)); |
| 2016 | |
| 2017 | /* Mark the lwps we're resuming as resumed. */ |
| 2018 | iterate_over_lwps (ptid, resume_set_callback, NULL); |
| 2019 | |
| 2020 | /* See if it's the current inferior that should be handled |
| 2021 | specially. */ |
| 2022 | if (resume_many) |
| 2023 | lp = find_lwp_pid (inferior_ptid); |
| 2024 | else |
| 2025 | lp = find_lwp_pid (ptid); |
| 2026 | gdb_assert (lp != NULL); |
| 2027 | |
| 2028 | /* Remember if we're stepping. */ |
| 2029 | lp->step = step; |
| 2030 | lp->last_resume_kind = step ? resume_step : resume_continue; |
| 2031 | |
| 2032 | /* If we have a pending wait status for this thread, there is no |
| 2033 | point in resuming the process. But first make sure that |
| 2034 | linux_nat_wait won't preemptively handle the event - we |
| 2035 | should never take this short-circuit if we are going to |
| 2036 | leave LP running, since we have skipped resuming all the |
| 2037 | other threads. This bit of code needs to be synchronized |
| 2038 | with linux_nat_wait. */ |
| 2039 | |
| 2040 | if (lp->status && WIFSTOPPED (lp->status)) |
| 2041 | { |
| 2042 | if (!lp->step |
| 2043 | && WSTOPSIG (lp->status) |
| 2044 | && sigismember (&pass_mask, WSTOPSIG (lp->status))) |
| 2045 | { |
| 2046 | if (debug_linux_nat) |
| 2047 | fprintf_unfiltered (gdb_stdlog, |
| 2048 | "LLR: Not short circuiting for ignored " |
| 2049 | "status 0x%x\n", lp->status); |
| 2050 | |
| 2051 | /* FIXME: What should we do if we are supposed to continue |
| 2052 | this thread with a signal? */ |
| 2053 | gdb_assert (signo == GDB_SIGNAL_0); |
| 2054 | signo = gdb_signal_from_host (WSTOPSIG (lp->status)); |
| 2055 | lp->status = 0; |
| 2056 | } |
| 2057 | } |
| 2058 | |
| 2059 | if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE) |
| 2060 | { |
| 2061 | /* FIXME: What should we do if we are supposed to continue |
| 2062 | this thread with a signal? */ |
| 2063 | gdb_assert (signo == GDB_SIGNAL_0); |
| 2064 | |
| 2065 | if (debug_linux_nat) |
| 2066 | fprintf_unfiltered (gdb_stdlog, |
| 2067 | "LLR: Short circuiting for status 0x%x\n", |
| 2068 | lp->status); |
| 2069 | |
| 2070 | restore_child_signals_mask (&prev_mask); |
| 2071 | if (target_can_async_p ()) |
| 2072 | { |
| 2073 | target_async (inferior_event_handler, 0); |
| 2074 | /* Tell the event loop we have something to process. */ |
| 2075 | async_file_mark (); |
| 2076 | } |
| 2077 | return; |
| 2078 | } |
| 2079 | |
| 2080 | /* Mark LWP as not stopped to prevent it from being continued by |
| 2081 | linux_nat_resume_callback. */ |
| 2082 | lp->stopped = 0; |
| 2083 | |
| 2084 | if (resume_many) |
| 2085 | iterate_over_lwps (ptid, linux_nat_resume_callback, NULL); |
| 2086 | |
| 2087 | /* Convert to something the lower layer understands. */ |
| 2088 | ptid = pid_to_ptid (GET_LWP (lp->ptid)); |
| 2089 | |
| 2090 | if (linux_nat_prepare_to_resume != NULL) |
| 2091 | linux_nat_prepare_to_resume (lp); |
| 2092 | linux_ops->to_resume (linux_ops, ptid, step, signo); |
| 2093 | lp->stopped_by_watchpoint = 0; |
| 2094 | |
| 2095 | if (debug_linux_nat) |
| 2096 | fprintf_unfiltered (gdb_stdlog, |
| 2097 | "LLR: %s %s, %s (resume event thread)\n", |
| 2098 | step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
| 2099 | target_pid_to_str (ptid), |
| 2100 | (signo != GDB_SIGNAL_0 |
| 2101 | ? strsignal (gdb_signal_to_host (signo)) : "0")); |
| 2102 | |
| 2103 | restore_child_signals_mask (&prev_mask); |
| 2104 | if (target_can_async_p ()) |
| 2105 | target_async (inferior_event_handler, 0); |
| 2106 | } |
| 2107 | |
| 2108 | /* Send a signal to an LWP. */ |
| 2109 | |
| 2110 | static int |
| 2111 | kill_lwp (int lwpid, int signo) |
| 2112 | { |
| 2113 | /* Use tkill, if possible, in case we are using nptl threads. If tkill |
| 2114 | fails, then we are not using nptl threads and we should be using kill. */ |
| 2115 | |
| 2116 | #ifdef HAVE_TKILL_SYSCALL |
| 2117 | { |
| 2118 | static int tkill_failed; |
| 2119 | |
| 2120 | if (!tkill_failed) |
| 2121 | { |
| 2122 | int ret; |
| 2123 | |
| 2124 | errno = 0; |
| 2125 | ret = syscall (__NR_tkill, lwpid, signo); |
| 2126 | if (errno != ENOSYS) |
| 2127 | return ret; |
| 2128 | tkill_failed = 1; |
| 2129 | } |
| 2130 | } |
| 2131 | #endif |
| 2132 | |
| 2133 | return kill (lwpid, signo); |
| 2134 | } |
| 2135 | |
| 2136 | /* Handle a GNU/Linux syscall trap wait response. If we see a syscall |
| 2137 | event, check if the core is interested in it: if not, ignore the |
| 2138 | event, and keep waiting; otherwise, we need to toggle the LWP's |
| 2139 | syscall entry/exit status, since the ptrace event itself doesn't |
| 2140 | indicate it, and report the trap to higher layers. */ |
| 2141 | |
| 2142 | static int |
| 2143 | linux_handle_syscall_trap (struct lwp_info *lp, int stopping) |
| 2144 | { |
| 2145 | struct target_waitstatus *ourstatus = &lp->waitstatus; |
| 2146 | struct gdbarch *gdbarch = target_thread_architecture (lp->ptid); |
| 2147 | int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid); |
| 2148 | |
| 2149 | if (stopping) |
| 2150 | { |
| 2151 | /* If we're stopping threads, there's a SIGSTOP pending, which |
| 2152 | makes it so that the LWP reports an immediate syscall return, |
| 2153 | followed by the SIGSTOP. Skip seeing that "return" using |
| 2154 | PTRACE_CONT directly, and let stop_wait_callback collect the |
| 2155 | SIGSTOP. Later when the thread is resumed, a new syscall |
| 2156 | entry event. If we didn't do this (and returned 0), we'd |
| 2157 | leave a syscall entry pending, and our caller, by using |
| 2158 | PTRACE_CONT to collect the SIGSTOP, skips the syscall return |
| 2159 | itself. Later, when the user re-resumes this LWP, we'd see |
| 2160 | another syscall entry event and we'd mistake it for a return. |
| 2161 | |
| 2162 | If stop_wait_callback didn't force the SIGSTOP out of the LWP |
| 2163 | (leaving immediately with LWP->signalled set, without issuing |
| 2164 | a PTRACE_CONT), it would still be problematic to leave this |
| 2165 | syscall enter pending, as later when the thread is resumed, |
| 2166 | it would then see the same syscall exit mentioned above, |
| 2167 | followed by the delayed SIGSTOP, while the syscall didn't |
| 2168 | actually get to execute. It seems it would be even more |
| 2169 | confusing to the user. */ |
| 2170 | |
| 2171 | if (debug_linux_nat) |
| 2172 | fprintf_unfiltered (gdb_stdlog, |
| 2173 | "LHST: ignoring syscall %d " |
| 2174 | "for LWP %ld (stopping threads), " |
| 2175 | "resuming with PTRACE_CONT for SIGSTOP\n", |
| 2176 | syscall_number, |
| 2177 | GET_LWP (lp->ptid)); |
| 2178 | |
| 2179 | lp->syscall_state = TARGET_WAITKIND_IGNORE; |
| 2180 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); |
| 2181 | return 1; |
| 2182 | } |
| 2183 | |
| 2184 | if (catch_syscall_enabled ()) |
| 2185 | { |
| 2186 | /* Always update the entry/return state, even if this particular |
| 2187 | syscall isn't interesting to the core now. In async mode, |
| 2188 | the user could install a new catchpoint for this syscall |
| 2189 | between syscall enter/return, and we'll need to know to |
| 2190 | report a syscall return if that happens. */ |
| 2191 | lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY |
| 2192 | ? TARGET_WAITKIND_SYSCALL_RETURN |
| 2193 | : TARGET_WAITKIND_SYSCALL_ENTRY); |
| 2194 | |
| 2195 | if (catching_syscall_number (syscall_number)) |
| 2196 | { |
| 2197 | /* Alright, an event to report. */ |
| 2198 | ourstatus->kind = lp->syscall_state; |
| 2199 | ourstatus->value.syscall_number = syscall_number; |
| 2200 | |
| 2201 | if (debug_linux_nat) |
| 2202 | fprintf_unfiltered (gdb_stdlog, |
| 2203 | "LHST: stopping for %s of syscall %d" |
| 2204 | " for LWP %ld\n", |
| 2205 | lp->syscall_state |
| 2206 | == TARGET_WAITKIND_SYSCALL_ENTRY |
| 2207 | ? "entry" : "return", |
| 2208 | syscall_number, |
| 2209 | GET_LWP (lp->ptid)); |
| 2210 | return 0; |
| 2211 | } |
| 2212 | |
| 2213 | if (debug_linux_nat) |
| 2214 | fprintf_unfiltered (gdb_stdlog, |
| 2215 | "LHST: ignoring %s of syscall %d " |
| 2216 | "for LWP %ld\n", |
| 2217 | lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY |
| 2218 | ? "entry" : "return", |
| 2219 | syscall_number, |
| 2220 | GET_LWP (lp->ptid)); |
| 2221 | } |
| 2222 | else |
| 2223 | { |
| 2224 | /* If we had been syscall tracing, and hence used PT_SYSCALL |
| 2225 | before on this LWP, it could happen that the user removes all |
| 2226 | syscall catchpoints before we get to process this event. |
| 2227 | There are two noteworthy issues here: |
| 2228 | |
| 2229 | - When stopped at a syscall entry event, resuming with |
| 2230 | PT_STEP still resumes executing the syscall and reports a |
| 2231 | syscall return. |
| 2232 | |
| 2233 | - Only PT_SYSCALL catches syscall enters. If we last |
| 2234 | single-stepped this thread, then this event can't be a |
| 2235 | syscall enter. If we last single-stepped this thread, this |
| 2236 | has to be a syscall exit. |
| 2237 | |
| 2238 | The points above mean that the next resume, be it PT_STEP or |
| 2239 | PT_CONTINUE, can not trigger a syscall trace event. */ |
| 2240 | if (debug_linux_nat) |
| 2241 | fprintf_unfiltered (gdb_stdlog, |
| 2242 | "LHST: caught syscall event " |
| 2243 | "with no syscall catchpoints." |
| 2244 | " %d for LWP %ld, ignoring\n", |
| 2245 | syscall_number, |
| 2246 | GET_LWP (lp->ptid)); |
| 2247 | lp->syscall_state = TARGET_WAITKIND_IGNORE; |
| 2248 | } |
| 2249 | |
| 2250 | /* The core isn't interested in this event. For efficiency, avoid |
| 2251 | stopping all threads only to have the core resume them all again. |
| 2252 | Since we're not stopping threads, if we're still syscall tracing |
| 2253 | and not stepping, we can't use PTRACE_CONT here, as we'd miss any |
| 2254 | subsequent syscall. Simply resume using the inf-ptrace layer, |
| 2255 | which knows when to use PT_SYSCALL or PT_CONTINUE. */ |
| 2256 | |
| 2257 | /* Note that gdbarch_get_syscall_number may access registers, hence |
| 2258 | fill a regcache. */ |
| 2259 | registers_changed (); |
| 2260 | if (linux_nat_prepare_to_resume != NULL) |
| 2261 | linux_nat_prepare_to_resume (lp); |
| 2262 | linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)), |
| 2263 | lp->step, GDB_SIGNAL_0); |
| 2264 | return 1; |
| 2265 | } |
| 2266 | |
| 2267 | /* Handle a GNU/Linux extended wait response. If we see a clone |
| 2268 | event, we need to add the new LWP to our list (and not report the |
| 2269 | trap to higher layers). This function returns non-zero if the |
| 2270 | event should be ignored and we should wait again. If STOPPING is |
| 2271 | true, the new LWP remains stopped, otherwise it is continued. */ |
| 2272 | |
| 2273 | static int |
| 2274 | linux_handle_extended_wait (struct lwp_info *lp, int status, |
| 2275 | int stopping) |
| 2276 | { |
| 2277 | int pid = GET_LWP (lp->ptid); |
| 2278 | struct target_waitstatus *ourstatus = &lp->waitstatus; |
| 2279 | int event = status >> 16; |
| 2280 | |
| 2281 | if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK |
| 2282 | || event == PTRACE_EVENT_CLONE) |
| 2283 | { |
| 2284 | unsigned long new_pid; |
| 2285 | int ret; |
| 2286 | |
| 2287 | ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid); |
| 2288 | |
| 2289 | /* If we haven't already seen the new PID stop, wait for it now. */ |
| 2290 | if (! pull_pid_from_list (&stopped_pids, new_pid, &status)) |
| 2291 | { |
| 2292 | /* The new child has a pending SIGSTOP. We can't affect it until it |
| 2293 | hits the SIGSTOP, but we're already attached. */ |
| 2294 | ret = my_waitpid (new_pid, &status, |
| 2295 | (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0); |
| 2296 | if (ret == -1) |
| 2297 | perror_with_name (_("waiting for new child")); |
| 2298 | else if (ret != new_pid) |
| 2299 | internal_error (__FILE__, __LINE__, |
| 2300 | _("wait returned unexpected PID %d"), ret); |
| 2301 | else if (!WIFSTOPPED (status)) |
| 2302 | internal_error (__FILE__, __LINE__, |
| 2303 | _("wait returned unexpected status 0x%x"), status); |
| 2304 | } |
| 2305 | |
| 2306 | ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0); |
| 2307 | |
| 2308 | if (event == PTRACE_EVENT_FORK |
| 2309 | && linux_fork_checkpointing_p (GET_PID (lp->ptid))) |
| 2310 | { |
| 2311 | /* Handle checkpointing by linux-fork.c here as a special |
| 2312 | case. We don't want the follow-fork-mode or 'catch fork' |
| 2313 | to interfere with this. */ |
| 2314 | |
| 2315 | /* This won't actually modify the breakpoint list, but will |
| 2316 | physically remove the breakpoints from the child. */ |
| 2317 | detach_breakpoints (new_pid); |
| 2318 | |
| 2319 | /* Retain child fork in ptrace (stopped) state. */ |
| 2320 | if (!find_fork_pid (new_pid)) |
| 2321 | add_fork (new_pid); |
| 2322 | |
| 2323 | /* Report as spurious, so that infrun doesn't want to follow |
| 2324 | this fork. We're actually doing an infcall in |
| 2325 | linux-fork.c. */ |
| 2326 | ourstatus->kind = TARGET_WAITKIND_SPURIOUS; |
| 2327 | linux_enable_event_reporting (pid_to_ptid (new_pid)); |
| 2328 | |
| 2329 | /* Report the stop to the core. */ |
| 2330 | return 0; |
| 2331 | } |
| 2332 | |
| 2333 | if (event == PTRACE_EVENT_FORK) |
| 2334 | ourstatus->kind = TARGET_WAITKIND_FORKED; |
| 2335 | else if (event == PTRACE_EVENT_VFORK) |
| 2336 | ourstatus->kind = TARGET_WAITKIND_VFORKED; |
| 2337 | else |
| 2338 | { |
| 2339 | struct lwp_info *new_lp; |
| 2340 | |
| 2341 | ourstatus->kind = TARGET_WAITKIND_IGNORE; |
| 2342 | |
| 2343 | if (debug_linux_nat) |
| 2344 | fprintf_unfiltered (gdb_stdlog, |
| 2345 | "LHEW: Got clone event " |
| 2346 | "from LWP %d, new child is LWP %ld\n", |
| 2347 | pid, new_pid); |
| 2348 | |
| 2349 | new_lp = add_lwp (BUILD_LWP (new_pid, GET_PID (lp->ptid))); |
| 2350 | new_lp->cloned = 1; |
| 2351 | new_lp->stopped = 1; |
| 2352 | |
| 2353 | if (WSTOPSIG (status) != SIGSTOP) |
| 2354 | { |
| 2355 | /* This can happen if someone starts sending signals to |
| 2356 | the new thread before it gets a chance to run, which |
| 2357 | have a lower number than SIGSTOP (e.g. SIGUSR1). |
| 2358 | This is an unlikely case, and harder to handle for |
| 2359 | fork / vfork than for clone, so we do not try - but |
| 2360 | we handle it for clone events here. We'll send |
| 2361 | the other signal on to the thread below. */ |
| 2362 | |
| 2363 | new_lp->signalled = 1; |
| 2364 | } |
| 2365 | else |
| 2366 | { |
| 2367 | struct thread_info *tp; |
| 2368 | |
| 2369 | /* When we stop for an event in some other thread, and |
| 2370 | pull the thread list just as this thread has cloned, |
| 2371 | we'll have seen the new thread in the thread_db list |
| 2372 | before handling the CLONE event (glibc's |
| 2373 | pthread_create adds the new thread to the thread list |
| 2374 | before clone'ing, and has the kernel fill in the |
| 2375 | thread's tid on the clone call with |
| 2376 | CLONE_PARENT_SETTID). If that happened, and the core |
| 2377 | had requested the new thread to stop, we'll have |
| 2378 | killed it with SIGSTOP. But since SIGSTOP is not an |
| 2379 | RT signal, it can only be queued once. We need to be |
| 2380 | careful to not resume the LWP if we wanted it to |
| 2381 | stop. In that case, we'll leave the SIGSTOP pending. |
| 2382 | It will later be reported as GDB_SIGNAL_0. */ |
| 2383 | tp = find_thread_ptid (new_lp->ptid); |
| 2384 | if (tp != NULL && tp->stop_requested) |
| 2385 | new_lp->last_resume_kind = resume_stop; |
| 2386 | else |
| 2387 | status = 0; |
| 2388 | } |
| 2389 | |
| 2390 | if (non_stop) |
| 2391 | { |
| 2392 | /* Add the new thread to GDB's lists as soon as possible |
| 2393 | so that: |
| 2394 | |
| 2395 | 1) the frontend doesn't have to wait for a stop to |
| 2396 | display them, and, |
| 2397 | |
| 2398 | 2) we tag it with the correct running state. */ |
| 2399 | |
| 2400 | /* If the thread_db layer is active, let it know about |
| 2401 | this new thread, and add it to GDB's list. */ |
| 2402 | if (!thread_db_attach_lwp (new_lp->ptid)) |
| 2403 | { |
| 2404 | /* We're not using thread_db. Add it to GDB's |
| 2405 | list. */ |
| 2406 | target_post_attach (GET_LWP (new_lp->ptid)); |
| 2407 | add_thread (new_lp->ptid); |
| 2408 | } |
| 2409 | |
| 2410 | if (!stopping) |
| 2411 | { |
| 2412 | set_running (new_lp->ptid, 1); |
| 2413 | set_executing (new_lp->ptid, 1); |
| 2414 | /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced |
| 2415 | resume_stop. */ |
| 2416 | new_lp->last_resume_kind = resume_continue; |
| 2417 | } |
| 2418 | } |
| 2419 | |
| 2420 | if (status != 0) |
| 2421 | { |
| 2422 | /* We created NEW_LP so it cannot yet contain STATUS. */ |
| 2423 | gdb_assert (new_lp->status == 0); |
| 2424 | |
| 2425 | /* Save the wait status to report later. */ |
| 2426 | if (debug_linux_nat) |
| 2427 | fprintf_unfiltered (gdb_stdlog, |
| 2428 | "LHEW: waitpid of new LWP %ld, " |
| 2429 | "saving status %s\n", |
| 2430 | (long) GET_LWP (new_lp->ptid), |
| 2431 | status_to_str (status)); |
| 2432 | new_lp->status = status; |
| 2433 | } |
| 2434 | |
| 2435 | /* Note the need to use the low target ops to resume, to |
| 2436 | handle resuming with PT_SYSCALL if we have syscall |
| 2437 | catchpoints. */ |
| 2438 | if (!stopping) |
| 2439 | { |
| 2440 | new_lp->resumed = 1; |
| 2441 | |
| 2442 | if (status == 0) |
| 2443 | { |
| 2444 | gdb_assert (new_lp->last_resume_kind == resume_continue); |
| 2445 | if (debug_linux_nat) |
| 2446 | fprintf_unfiltered (gdb_stdlog, |
| 2447 | "LHEW: resuming new LWP %ld\n", |
| 2448 | GET_LWP (new_lp->ptid)); |
| 2449 | if (linux_nat_prepare_to_resume != NULL) |
| 2450 | linux_nat_prepare_to_resume (new_lp); |
| 2451 | linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid), |
| 2452 | 0, GDB_SIGNAL_0); |
| 2453 | new_lp->stopped = 0; |
| 2454 | } |
| 2455 | } |
| 2456 | |
| 2457 | if (debug_linux_nat) |
| 2458 | fprintf_unfiltered (gdb_stdlog, |
| 2459 | "LHEW: resuming parent LWP %d\n", pid); |
| 2460 | if (linux_nat_prepare_to_resume != NULL) |
| 2461 | linux_nat_prepare_to_resume (lp); |
| 2462 | linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)), |
| 2463 | 0, GDB_SIGNAL_0); |
| 2464 | |
| 2465 | return 1; |
| 2466 | } |
| 2467 | |
| 2468 | return 0; |
| 2469 | } |
| 2470 | |
| 2471 | if (event == PTRACE_EVENT_EXEC) |
| 2472 | { |
| 2473 | if (debug_linux_nat) |
| 2474 | fprintf_unfiltered (gdb_stdlog, |
| 2475 | "LHEW: Got exec event from LWP %ld\n", |
| 2476 | GET_LWP (lp->ptid)); |
| 2477 | |
| 2478 | ourstatus->kind = TARGET_WAITKIND_EXECD; |
| 2479 | ourstatus->value.execd_pathname |
| 2480 | = xstrdup (linux_child_pid_to_exec_file (pid)); |
| 2481 | |
| 2482 | return 0; |
| 2483 | } |
| 2484 | |
| 2485 | if (event == PTRACE_EVENT_VFORK_DONE) |
| 2486 | { |
| 2487 | if (current_inferior ()->waiting_for_vfork_done) |
| 2488 | { |
| 2489 | if (debug_linux_nat) |
| 2490 | fprintf_unfiltered (gdb_stdlog, |
| 2491 | "LHEW: Got expected PTRACE_EVENT_" |
| 2492 | "VFORK_DONE from LWP %ld: stopping\n", |
| 2493 | GET_LWP (lp->ptid)); |
| 2494 | |
| 2495 | ourstatus->kind = TARGET_WAITKIND_VFORK_DONE; |
| 2496 | return 0; |
| 2497 | } |
| 2498 | |
| 2499 | if (debug_linux_nat) |
| 2500 | fprintf_unfiltered (gdb_stdlog, |
| 2501 | "LHEW: Got PTRACE_EVENT_VFORK_DONE " |
| 2502 | "from LWP %ld: resuming\n", |
| 2503 | GET_LWP (lp->ptid)); |
| 2504 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); |
| 2505 | return 1; |
| 2506 | } |
| 2507 | |
| 2508 | internal_error (__FILE__, __LINE__, |
| 2509 | _("unknown ptrace event %d"), event); |
| 2510 | } |
| 2511 | |
| 2512 | /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has |
| 2513 | exited. */ |
| 2514 | |
| 2515 | static int |
| 2516 | wait_lwp (struct lwp_info *lp) |
| 2517 | { |
| 2518 | pid_t pid; |
| 2519 | int status = 0; |
| 2520 | int thread_dead = 0; |
| 2521 | sigset_t prev_mask; |
| 2522 | |
| 2523 | gdb_assert (!lp->stopped); |
| 2524 | gdb_assert (lp->status == 0); |
| 2525 | |
| 2526 | /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */ |
| 2527 | block_child_signals (&prev_mask); |
| 2528 | |
| 2529 | for (;;) |
| 2530 | { |
| 2531 | /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind |
| 2532 | was right and we should just call sigsuspend. */ |
| 2533 | |
| 2534 | pid = my_waitpid (GET_LWP (lp->ptid), &status, WNOHANG); |
| 2535 | if (pid == -1 && errno == ECHILD) |
| 2536 | pid = my_waitpid (GET_LWP (lp->ptid), &status, __WCLONE | WNOHANG); |
| 2537 | if (pid == -1 && errno == ECHILD) |
| 2538 | { |
| 2539 | /* The thread has previously exited. We need to delete it |
| 2540 | now because, for some vendor 2.4 kernels with NPTL |
| 2541 | support backported, there won't be an exit event unless |
| 2542 | it is the main thread. 2.6 kernels will report an exit |
| 2543 | event for each thread that exits, as expected. */ |
| 2544 | thread_dead = 1; |
| 2545 | if (debug_linux_nat) |
| 2546 | fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n", |
| 2547 | target_pid_to_str (lp->ptid)); |
| 2548 | } |
| 2549 | if (pid != 0) |
| 2550 | break; |
| 2551 | |
| 2552 | /* Bugs 10970, 12702. |
| 2553 | Thread group leader may have exited in which case we'll lock up in |
| 2554 | waitpid if there are other threads, even if they are all zombies too. |
| 2555 | Basically, we're not supposed to use waitpid this way. |
| 2556 | __WCLONE is not applicable for the leader so we can't use that. |
| 2557 | LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED |
| 2558 | process; it gets ESRCH both for the zombie and for running processes. |
| 2559 | |
| 2560 | As a workaround, check if we're waiting for the thread group leader and |
| 2561 | if it's a zombie, and avoid calling waitpid if it is. |
| 2562 | |
| 2563 | This is racy, what if the tgl becomes a zombie right after we check? |
| 2564 | Therefore always use WNOHANG with sigsuspend - it is equivalent to |
| 2565 | waiting waitpid but linux_proc_pid_is_zombie is safe this way. */ |
| 2566 | |
| 2567 | if (GET_PID (lp->ptid) == GET_LWP (lp->ptid) |
| 2568 | && linux_proc_pid_is_zombie (GET_LWP (lp->ptid))) |
| 2569 | { |
| 2570 | thread_dead = 1; |
| 2571 | if (debug_linux_nat) |
| 2572 | fprintf_unfiltered (gdb_stdlog, |
| 2573 | "WL: Thread group leader %s vanished.\n", |
| 2574 | target_pid_to_str (lp->ptid)); |
| 2575 | break; |
| 2576 | } |
| 2577 | |
| 2578 | /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers |
| 2579 | get invoked despite our caller had them intentionally blocked by |
| 2580 | block_child_signals. This is sensitive only to the loop of |
| 2581 | linux_nat_wait_1 and there if we get called my_waitpid gets called |
| 2582 | again before it gets to sigsuspend so we can safely let the handlers |
| 2583 | get executed here. */ |
| 2584 | |
| 2585 | sigsuspend (&suspend_mask); |
| 2586 | } |
| 2587 | |
| 2588 | restore_child_signals_mask (&prev_mask); |
| 2589 | |
| 2590 | if (!thread_dead) |
| 2591 | { |
| 2592 | gdb_assert (pid == GET_LWP (lp->ptid)); |
| 2593 | |
| 2594 | if (debug_linux_nat) |
| 2595 | { |
| 2596 | fprintf_unfiltered (gdb_stdlog, |
| 2597 | "WL: waitpid %s received %s\n", |
| 2598 | target_pid_to_str (lp->ptid), |
| 2599 | status_to_str (status)); |
| 2600 | } |
| 2601 | |
| 2602 | /* Check if the thread has exited. */ |
| 2603 | if (WIFEXITED (status) || WIFSIGNALED (status)) |
| 2604 | { |
| 2605 | thread_dead = 1; |
| 2606 | if (debug_linux_nat) |
| 2607 | fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n", |
| 2608 | target_pid_to_str (lp->ptid)); |
| 2609 | } |
| 2610 | } |
| 2611 | |
| 2612 | if (thread_dead) |
| 2613 | { |
| 2614 | exit_lwp (lp); |
| 2615 | return 0; |
| 2616 | } |
| 2617 | |
| 2618 | gdb_assert (WIFSTOPPED (status)); |
| 2619 | |
| 2620 | /* Handle GNU/Linux's syscall SIGTRAPs. */ |
| 2621 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP) |
| 2622 | { |
| 2623 | /* No longer need the sysgood bit. The ptrace event ends up |
| 2624 | recorded in lp->waitstatus if we care for it. We can carry |
| 2625 | on handling the event like a regular SIGTRAP from here |
| 2626 | on. */ |
| 2627 | status = W_STOPCODE (SIGTRAP); |
| 2628 | if (linux_handle_syscall_trap (lp, 1)) |
| 2629 | return wait_lwp (lp); |
| 2630 | } |
| 2631 | |
| 2632 | /* Handle GNU/Linux's extended waitstatus for trace events. */ |
| 2633 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0) |
| 2634 | { |
| 2635 | if (debug_linux_nat) |
| 2636 | fprintf_unfiltered (gdb_stdlog, |
| 2637 | "WL: Handling extended status 0x%06x\n", |
| 2638 | status); |
| 2639 | if (linux_handle_extended_wait (lp, status, 1)) |
| 2640 | return wait_lwp (lp); |
| 2641 | } |
| 2642 | |
| 2643 | return status; |
| 2644 | } |
| 2645 | |
| 2646 | /* Send a SIGSTOP to LP. */ |
| 2647 | |
| 2648 | static int |
| 2649 | stop_callback (struct lwp_info *lp, void *data) |
| 2650 | { |
| 2651 | if (!lp->stopped && !lp->signalled) |
| 2652 | { |
| 2653 | int ret; |
| 2654 | |
| 2655 | if (debug_linux_nat) |
| 2656 | { |
| 2657 | fprintf_unfiltered (gdb_stdlog, |
| 2658 | "SC: kill %s **<SIGSTOP>**\n", |
| 2659 | target_pid_to_str (lp->ptid)); |
| 2660 | } |
| 2661 | errno = 0; |
| 2662 | ret = kill_lwp (GET_LWP (lp->ptid), SIGSTOP); |
| 2663 | if (debug_linux_nat) |
| 2664 | { |
| 2665 | fprintf_unfiltered (gdb_stdlog, |
| 2666 | "SC: lwp kill %d %s\n", |
| 2667 | ret, |
| 2668 | errno ? safe_strerror (errno) : "ERRNO-OK"); |
| 2669 | } |
| 2670 | |
| 2671 | lp->signalled = 1; |
| 2672 | gdb_assert (lp->status == 0); |
| 2673 | } |
| 2674 | |
| 2675 | return 0; |
| 2676 | } |
| 2677 | |
| 2678 | /* Request a stop on LWP. */ |
| 2679 | |
| 2680 | void |
| 2681 | linux_stop_lwp (struct lwp_info *lwp) |
| 2682 | { |
| 2683 | stop_callback (lwp, NULL); |
| 2684 | } |
| 2685 | |
| 2686 | /* Return non-zero if LWP PID has a pending SIGINT. */ |
| 2687 | |
| 2688 | static int |
| 2689 | linux_nat_has_pending_sigint (int pid) |
| 2690 | { |
| 2691 | sigset_t pending, blocked, ignored; |
| 2692 | |
| 2693 | linux_proc_pending_signals (pid, &pending, &blocked, &ignored); |
| 2694 | |
| 2695 | if (sigismember (&pending, SIGINT) |
| 2696 | && !sigismember (&ignored, SIGINT)) |
| 2697 | return 1; |
| 2698 | |
| 2699 | return 0; |
| 2700 | } |
| 2701 | |
| 2702 | /* Set a flag in LP indicating that we should ignore its next SIGINT. */ |
| 2703 | |
| 2704 | static int |
| 2705 | set_ignore_sigint (struct lwp_info *lp, void *data) |
| 2706 | { |
| 2707 | /* If a thread has a pending SIGINT, consume it; otherwise, set a |
| 2708 | flag to consume the next one. */ |
| 2709 | if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status) |
| 2710 | && WSTOPSIG (lp->status) == SIGINT) |
| 2711 | lp->status = 0; |
| 2712 | else |
| 2713 | lp->ignore_sigint = 1; |
| 2714 | |
| 2715 | return 0; |
| 2716 | } |
| 2717 | |
| 2718 | /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag. |
| 2719 | This function is called after we know the LWP has stopped; if the LWP |
| 2720 | stopped before the expected SIGINT was delivered, then it will never have |
| 2721 | arrived. Also, if the signal was delivered to a shared queue and consumed |
| 2722 | by a different thread, it will never be delivered to this LWP. */ |
| 2723 | |
| 2724 | static void |
| 2725 | maybe_clear_ignore_sigint (struct lwp_info *lp) |
| 2726 | { |
| 2727 | if (!lp->ignore_sigint) |
| 2728 | return; |
| 2729 | |
| 2730 | if (!linux_nat_has_pending_sigint (GET_LWP (lp->ptid))) |
| 2731 | { |
| 2732 | if (debug_linux_nat) |
| 2733 | fprintf_unfiltered (gdb_stdlog, |
| 2734 | "MCIS: Clearing bogus flag for %s\n", |
| 2735 | target_pid_to_str (lp->ptid)); |
| 2736 | lp->ignore_sigint = 0; |
| 2737 | } |
| 2738 | } |
| 2739 | |
| 2740 | /* Fetch the possible triggered data watchpoint info and store it in |
| 2741 | LP. |
| 2742 | |
| 2743 | On some archs, like x86, that use debug registers to set |
| 2744 | watchpoints, it's possible that the way to know which watched |
| 2745 | address trapped, is to check the register that is used to select |
| 2746 | which address to watch. Problem is, between setting the watchpoint |
| 2747 | and reading back which data address trapped, the user may change |
| 2748 | the set of watchpoints, and, as a consequence, GDB changes the |
| 2749 | debug registers in the inferior. To avoid reading back a stale |
| 2750 | stopped-data-address when that happens, we cache in LP the fact |
| 2751 | that a watchpoint trapped, and the corresponding data address, as |
| 2752 | soon as we see LP stop with a SIGTRAP. If GDB changes the debug |
| 2753 | registers meanwhile, we have the cached data we can rely on. */ |
| 2754 | |
| 2755 | static void |
| 2756 | save_sigtrap (struct lwp_info *lp) |
| 2757 | { |
| 2758 | struct cleanup *old_chain; |
| 2759 | |
| 2760 | if (linux_ops->to_stopped_by_watchpoint == NULL) |
| 2761 | { |
| 2762 | lp->stopped_by_watchpoint = 0; |
| 2763 | return; |
| 2764 | } |
| 2765 | |
| 2766 | old_chain = save_inferior_ptid (); |
| 2767 | inferior_ptid = lp->ptid; |
| 2768 | |
| 2769 | lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint (); |
| 2770 | |
| 2771 | if (lp->stopped_by_watchpoint) |
| 2772 | { |
| 2773 | if (linux_ops->to_stopped_data_address != NULL) |
| 2774 | lp->stopped_data_address_p = |
| 2775 | linux_ops->to_stopped_data_address (¤t_target, |
| 2776 | &lp->stopped_data_address); |
| 2777 | else |
| 2778 | lp->stopped_data_address_p = 0; |
| 2779 | } |
| 2780 | |
| 2781 | do_cleanups (old_chain); |
| 2782 | } |
| 2783 | |
| 2784 | /* See save_sigtrap. */ |
| 2785 | |
| 2786 | static int |
| 2787 | linux_nat_stopped_by_watchpoint (void) |
| 2788 | { |
| 2789 | struct lwp_info *lp = find_lwp_pid (inferior_ptid); |
| 2790 | |
| 2791 | gdb_assert (lp != NULL); |
| 2792 | |
| 2793 | return lp->stopped_by_watchpoint; |
| 2794 | } |
| 2795 | |
| 2796 | static int |
| 2797 | linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p) |
| 2798 | { |
| 2799 | struct lwp_info *lp = find_lwp_pid (inferior_ptid); |
| 2800 | |
| 2801 | gdb_assert (lp != NULL); |
| 2802 | |
| 2803 | *addr_p = lp->stopped_data_address; |
| 2804 | |
| 2805 | return lp->stopped_data_address_p; |
| 2806 | } |
| 2807 | |
| 2808 | /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */ |
| 2809 | |
| 2810 | static int |
| 2811 | sigtrap_is_event (int status) |
| 2812 | { |
| 2813 | return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP; |
| 2814 | } |
| 2815 | |
| 2816 | /* SIGTRAP-like events recognizer. */ |
| 2817 | |
| 2818 | static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event; |
| 2819 | |
| 2820 | /* Check for SIGTRAP-like events in LP. */ |
| 2821 | |
| 2822 | static int |
| 2823 | linux_nat_lp_status_is_event (struct lwp_info *lp) |
| 2824 | { |
| 2825 | /* We check for lp->waitstatus in addition to lp->status, because we can |
| 2826 | have pending process exits recorded in lp->status |
| 2827 | and W_EXITCODE(0,0) == 0. We should probably have an additional |
| 2828 | lp->status_p flag. */ |
| 2829 | |
| 2830 | return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE |
| 2831 | && linux_nat_status_is_event (lp->status)); |
| 2832 | } |
| 2833 | |
| 2834 | /* Set alternative SIGTRAP-like events recognizer. If |
| 2835 | breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be |
| 2836 | applied. */ |
| 2837 | |
| 2838 | void |
| 2839 | linux_nat_set_status_is_event (struct target_ops *t, |
| 2840 | int (*status_is_event) (int status)) |
| 2841 | { |
| 2842 | linux_nat_status_is_event = status_is_event; |
| 2843 | } |
| 2844 | |
| 2845 | /* Wait until LP is stopped. */ |
| 2846 | |
| 2847 | static int |
| 2848 | stop_wait_callback (struct lwp_info *lp, void *data) |
| 2849 | { |
| 2850 | struct inferior *inf = find_inferior_pid (GET_PID (lp->ptid)); |
| 2851 | |
| 2852 | /* If this is a vfork parent, bail out, it is not going to report |
| 2853 | any SIGSTOP until the vfork is done with. */ |
| 2854 | if (inf->vfork_child != NULL) |
| 2855 | return 0; |
| 2856 | |
| 2857 | if (!lp->stopped) |
| 2858 | { |
| 2859 | int status; |
| 2860 | |
| 2861 | status = wait_lwp (lp); |
| 2862 | if (status == 0) |
| 2863 | return 0; |
| 2864 | |
| 2865 | if (lp->ignore_sigint && WIFSTOPPED (status) |
| 2866 | && WSTOPSIG (status) == SIGINT) |
| 2867 | { |
| 2868 | lp->ignore_sigint = 0; |
| 2869 | |
| 2870 | errno = 0; |
| 2871 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); |
| 2872 | if (debug_linux_nat) |
| 2873 | fprintf_unfiltered (gdb_stdlog, |
| 2874 | "PTRACE_CONT %s, 0, 0 (%s) " |
| 2875 | "(discarding SIGINT)\n", |
| 2876 | target_pid_to_str (lp->ptid), |
| 2877 | errno ? safe_strerror (errno) : "OK"); |
| 2878 | |
| 2879 | return stop_wait_callback (lp, NULL); |
| 2880 | } |
| 2881 | |
| 2882 | maybe_clear_ignore_sigint (lp); |
| 2883 | |
| 2884 | if (WSTOPSIG (status) != SIGSTOP) |
| 2885 | { |
| 2886 | /* The thread was stopped with a signal other than SIGSTOP. */ |
| 2887 | |
| 2888 | save_sigtrap (lp); |
| 2889 | |
| 2890 | if (debug_linux_nat) |
| 2891 | fprintf_unfiltered (gdb_stdlog, |
| 2892 | "SWC: Pending event %s in %s\n", |
| 2893 | status_to_str ((int) status), |
| 2894 | target_pid_to_str (lp->ptid)); |
| 2895 | |
| 2896 | /* Save the sigtrap event. */ |
| 2897 | lp->status = status; |
| 2898 | gdb_assert (!lp->stopped); |
| 2899 | gdb_assert (lp->signalled); |
| 2900 | lp->stopped = 1; |
| 2901 | } |
| 2902 | else |
| 2903 | { |
| 2904 | /* We caught the SIGSTOP that we intended to catch, so |
| 2905 | there's no SIGSTOP pending. */ |
| 2906 | |
| 2907 | if (debug_linux_nat) |
| 2908 | fprintf_unfiltered (gdb_stdlog, |
| 2909 | "SWC: Delayed SIGSTOP caught for %s.\n", |
| 2910 | target_pid_to_str (lp->ptid)); |
| 2911 | |
| 2912 | lp->stopped = 1; |
| 2913 | |
| 2914 | /* Reset SIGNALLED only after the stop_wait_callback call |
| 2915 | above as it does gdb_assert on SIGNALLED. */ |
| 2916 | lp->signalled = 0; |
| 2917 | } |
| 2918 | } |
| 2919 | |
| 2920 | return 0; |
| 2921 | } |
| 2922 | |
| 2923 | /* Return non-zero if LP has a wait status pending. */ |
| 2924 | |
| 2925 | static int |
| 2926 | status_callback (struct lwp_info *lp, void *data) |
| 2927 | { |
| 2928 | /* Only report a pending wait status if we pretend that this has |
| 2929 | indeed been resumed. */ |
| 2930 | if (!lp->resumed) |
| 2931 | return 0; |
| 2932 | |
| 2933 | if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE) |
| 2934 | { |
| 2935 | /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event, |
| 2936 | or a pending process exit. Note that `W_EXITCODE(0,0) == |
| 2937 | 0', so a clean process exit can not be stored pending in |
| 2938 | lp->status, it is indistinguishable from |
| 2939 | no-pending-status. */ |
| 2940 | return 1; |
| 2941 | } |
| 2942 | |
| 2943 | if (lp->status != 0) |
| 2944 | return 1; |
| 2945 | |
| 2946 | return 0; |
| 2947 | } |
| 2948 | |
| 2949 | /* Return non-zero if LP isn't stopped. */ |
| 2950 | |
| 2951 | static int |
| 2952 | running_callback (struct lwp_info *lp, void *data) |
| 2953 | { |
| 2954 | return (!lp->stopped |
| 2955 | || ((lp->status != 0 |
| 2956 | || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE) |
| 2957 | && lp->resumed)); |
| 2958 | } |
| 2959 | |
| 2960 | /* Count the LWP's that have had events. */ |
| 2961 | |
| 2962 | static int |
| 2963 | count_events_callback (struct lwp_info *lp, void *data) |
| 2964 | { |
| 2965 | int *count = data; |
| 2966 | |
| 2967 | gdb_assert (count != NULL); |
| 2968 | |
| 2969 | /* Count only resumed LWPs that have a SIGTRAP event pending. */ |
| 2970 | if (lp->resumed && linux_nat_lp_status_is_event (lp)) |
| 2971 | (*count)++; |
| 2972 | |
| 2973 | return 0; |
| 2974 | } |
| 2975 | |
| 2976 | /* Select the LWP (if any) that is currently being single-stepped. */ |
| 2977 | |
| 2978 | static int |
| 2979 | select_singlestep_lwp_callback (struct lwp_info *lp, void *data) |
| 2980 | { |
| 2981 | if (lp->last_resume_kind == resume_step |
| 2982 | && lp->status != 0) |
| 2983 | return 1; |
| 2984 | else |
| 2985 | return 0; |
| 2986 | } |
| 2987 | |
| 2988 | /* Select the Nth LWP that has had a SIGTRAP event. */ |
| 2989 | |
| 2990 | static int |
| 2991 | select_event_lwp_callback (struct lwp_info *lp, void *data) |
| 2992 | { |
| 2993 | int *selector = data; |
| 2994 | |
| 2995 | gdb_assert (selector != NULL); |
| 2996 | |
| 2997 | /* Select only resumed LWPs that have a SIGTRAP event pending. */ |
| 2998 | if (lp->resumed && linux_nat_lp_status_is_event (lp)) |
| 2999 | if ((*selector)-- == 0) |
| 3000 | return 1; |
| 3001 | |
| 3002 | return 0; |
| 3003 | } |
| 3004 | |
| 3005 | static int |
| 3006 | cancel_breakpoint (struct lwp_info *lp) |
| 3007 | { |
| 3008 | /* Arrange for a breakpoint to be hit again later. We don't keep |
| 3009 | the SIGTRAP status and don't forward the SIGTRAP signal to the |
| 3010 | LWP. We will handle the current event, eventually we will resume |
| 3011 | this LWP, and this breakpoint will trap again. |
| 3012 | |
| 3013 | If we do not do this, then we run the risk that the user will |
| 3014 | delete or disable the breakpoint, but the LWP will have already |
| 3015 | tripped on it. */ |
| 3016 | |
| 3017 | struct regcache *regcache = get_thread_regcache (lp->ptid); |
| 3018 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 3019 | CORE_ADDR pc; |
| 3020 | |
| 3021 | pc = regcache_read_pc (regcache) - gdbarch_decr_pc_after_break (gdbarch); |
| 3022 | if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc)) |
| 3023 | { |
| 3024 | if (debug_linux_nat) |
| 3025 | fprintf_unfiltered (gdb_stdlog, |
| 3026 | "CB: Push back breakpoint for %s\n", |
| 3027 | target_pid_to_str (lp->ptid)); |
| 3028 | |
| 3029 | /* Back up the PC if necessary. */ |
| 3030 | if (gdbarch_decr_pc_after_break (gdbarch)) |
| 3031 | regcache_write_pc (regcache, pc); |
| 3032 | |
| 3033 | return 1; |
| 3034 | } |
| 3035 | return 0; |
| 3036 | } |
| 3037 | |
| 3038 | static int |
| 3039 | cancel_breakpoints_callback (struct lwp_info *lp, void *data) |
| 3040 | { |
| 3041 | struct lwp_info *event_lp = data; |
| 3042 | |
| 3043 | /* Leave the LWP that has been elected to receive a SIGTRAP alone. */ |
| 3044 | if (lp == event_lp) |
| 3045 | return 0; |
| 3046 | |
| 3047 | /* If a LWP other than the LWP that we're reporting an event for has |
| 3048 | hit a GDB breakpoint (as opposed to some random trap signal), |
| 3049 | then just arrange for it to hit it again later. We don't keep |
| 3050 | the SIGTRAP status and don't forward the SIGTRAP signal to the |
| 3051 | LWP. We will handle the current event, eventually we will resume |
| 3052 | all LWPs, and this one will get its breakpoint trap again. |
| 3053 | |
| 3054 | If we do not do this, then we run the risk that the user will |
| 3055 | delete or disable the breakpoint, but the LWP will have already |
| 3056 | tripped on it. */ |
| 3057 | |
| 3058 | if (linux_nat_lp_status_is_event (lp) |
| 3059 | && cancel_breakpoint (lp)) |
| 3060 | /* Throw away the SIGTRAP. */ |
| 3061 | lp->status = 0; |
| 3062 | |
| 3063 | return 0; |
| 3064 | } |
| 3065 | |
| 3066 | /* Select one LWP out of those that have events pending. */ |
| 3067 | |
| 3068 | static void |
| 3069 | select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status) |
| 3070 | { |
| 3071 | int num_events = 0; |
| 3072 | int random_selector; |
| 3073 | struct lwp_info *event_lp; |
| 3074 | |
| 3075 | /* Record the wait status for the original LWP. */ |
| 3076 | (*orig_lp)->status = *status; |
| 3077 | |
| 3078 | /* Give preference to any LWP that is being single-stepped. */ |
| 3079 | event_lp = iterate_over_lwps (filter, |
| 3080 | select_singlestep_lwp_callback, NULL); |
| 3081 | if (event_lp != NULL) |
| 3082 | { |
| 3083 | if (debug_linux_nat) |
| 3084 | fprintf_unfiltered (gdb_stdlog, |
| 3085 | "SEL: Select single-step %s\n", |
| 3086 | target_pid_to_str (event_lp->ptid)); |
| 3087 | } |
| 3088 | else |
| 3089 | { |
| 3090 | /* No single-stepping LWP. Select one at random, out of those |
| 3091 | which have had SIGTRAP events. */ |
| 3092 | |
| 3093 | /* First see how many SIGTRAP events we have. */ |
| 3094 | iterate_over_lwps (filter, count_events_callback, &num_events); |
| 3095 | |
| 3096 | /* Now randomly pick a LWP out of those that have had a SIGTRAP. */ |
| 3097 | random_selector = (int) |
| 3098 | ((num_events * (double) rand ()) / (RAND_MAX + 1.0)); |
| 3099 | |
| 3100 | if (debug_linux_nat && num_events > 1) |
| 3101 | fprintf_unfiltered (gdb_stdlog, |
| 3102 | "SEL: Found %d SIGTRAP events, selecting #%d\n", |
| 3103 | num_events, random_selector); |
| 3104 | |
| 3105 | event_lp = iterate_over_lwps (filter, |
| 3106 | select_event_lwp_callback, |
| 3107 | &random_selector); |
| 3108 | } |
| 3109 | |
| 3110 | if (event_lp != NULL) |
| 3111 | { |
| 3112 | /* Switch the event LWP. */ |
| 3113 | *orig_lp = event_lp; |
| 3114 | *status = event_lp->status; |
| 3115 | } |
| 3116 | |
| 3117 | /* Flush the wait status for the event LWP. */ |
| 3118 | (*orig_lp)->status = 0; |
| 3119 | } |
| 3120 | |
| 3121 | /* Return non-zero if LP has been resumed. */ |
| 3122 | |
| 3123 | static int |
| 3124 | resumed_callback (struct lwp_info *lp, void *data) |
| 3125 | { |
| 3126 | return lp->resumed; |
| 3127 | } |
| 3128 | |
| 3129 | /* Stop an active thread, verify it still exists, then resume it. If |
| 3130 | the thread ends up with a pending status, then it is not resumed, |
| 3131 | and *DATA (really a pointer to int), is set. */ |
| 3132 | |
| 3133 | static int |
| 3134 | stop_and_resume_callback (struct lwp_info *lp, void *data) |
| 3135 | { |
| 3136 | int *new_pending_p = data; |
| 3137 | |
| 3138 | if (!lp->stopped) |
| 3139 | { |
| 3140 | ptid_t ptid = lp->ptid; |
| 3141 | |
| 3142 | stop_callback (lp, NULL); |
| 3143 | stop_wait_callback (lp, NULL); |
| 3144 | |
| 3145 | /* Resume if the lwp still exists, and the core wanted it |
| 3146 | running. */ |
| 3147 | lp = find_lwp_pid (ptid); |
| 3148 | if (lp != NULL) |
| 3149 | { |
| 3150 | if (lp->last_resume_kind == resume_stop |
| 3151 | && lp->status == 0) |
| 3152 | { |
| 3153 | /* The core wanted the LWP to stop. Even if it stopped |
| 3154 | cleanly (with SIGSTOP), leave the event pending. */ |
| 3155 | if (debug_linux_nat) |
| 3156 | fprintf_unfiltered (gdb_stdlog, |
| 3157 | "SARC: core wanted LWP %ld stopped " |
| 3158 | "(leaving SIGSTOP pending)\n", |
| 3159 | GET_LWP (lp->ptid)); |
| 3160 | lp->status = W_STOPCODE (SIGSTOP); |
| 3161 | } |
| 3162 | |
| 3163 | if (lp->status == 0) |
| 3164 | { |
| 3165 | if (debug_linux_nat) |
| 3166 | fprintf_unfiltered (gdb_stdlog, |
| 3167 | "SARC: re-resuming LWP %ld\n", |
| 3168 | GET_LWP (lp->ptid)); |
| 3169 | resume_lwp (lp, lp->step, GDB_SIGNAL_0); |
| 3170 | } |
| 3171 | else |
| 3172 | { |
| 3173 | if (debug_linux_nat) |
| 3174 | fprintf_unfiltered (gdb_stdlog, |
| 3175 | "SARC: not re-resuming LWP %ld " |
| 3176 | "(has pending)\n", |
| 3177 | GET_LWP (lp->ptid)); |
| 3178 | if (new_pending_p) |
| 3179 | *new_pending_p = 1; |
| 3180 | } |
| 3181 | } |
| 3182 | } |
| 3183 | return 0; |
| 3184 | } |
| 3185 | |
| 3186 | /* Check if we should go on and pass this event to common code. |
| 3187 | Return the affected lwp if we are, or NULL otherwise. If we stop |
| 3188 | all lwps temporarily, we may end up with new pending events in some |
| 3189 | other lwp. In that case set *NEW_PENDING_P to true. */ |
| 3190 | |
| 3191 | static struct lwp_info * |
| 3192 | linux_nat_filter_event (int lwpid, int status, int *new_pending_p) |
| 3193 | { |
| 3194 | struct lwp_info *lp; |
| 3195 | |
| 3196 | *new_pending_p = 0; |
| 3197 | |
| 3198 | lp = find_lwp_pid (pid_to_ptid (lwpid)); |
| 3199 | |
| 3200 | /* Check for stop events reported by a process we didn't already |
| 3201 | know about - anything not already in our LWP list. |
| 3202 | |
| 3203 | If we're expecting to receive stopped processes after |
| 3204 | fork, vfork, and clone events, then we'll just add the |
| 3205 | new one to our list and go back to waiting for the event |
| 3206 | to be reported - the stopped process might be returned |
| 3207 | from waitpid before or after the event is. |
| 3208 | |
| 3209 | But note the case of a non-leader thread exec'ing after the |
| 3210 | leader having exited, and gone from our lists. The non-leader |
| 3211 | thread changes its tid to the tgid. */ |
| 3212 | |
| 3213 | if (WIFSTOPPED (status) && lp == NULL |
| 3214 | && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC)) |
| 3215 | { |
| 3216 | /* A multi-thread exec after we had seen the leader exiting. */ |
| 3217 | if (debug_linux_nat) |
| 3218 | fprintf_unfiltered (gdb_stdlog, |
| 3219 | "LLW: Re-adding thread group leader LWP %d.\n", |
| 3220 | lwpid); |
| 3221 | |
| 3222 | lp = add_lwp (BUILD_LWP (lwpid, lwpid)); |
| 3223 | lp->stopped = 1; |
| 3224 | lp->resumed = 1; |
| 3225 | add_thread (lp->ptid); |
| 3226 | } |
| 3227 | |
| 3228 | if (WIFSTOPPED (status) && !lp) |
| 3229 | { |
| 3230 | add_to_pid_list (&stopped_pids, lwpid, status); |
| 3231 | return NULL; |
| 3232 | } |
| 3233 | |
| 3234 | /* Make sure we don't report an event for the exit of an LWP not in |
| 3235 | our list, i.e. not part of the current process. This can happen |
| 3236 | if we detach from a program we originally forked and then it |
| 3237 | exits. */ |
| 3238 | if (!WIFSTOPPED (status) && !lp) |
| 3239 | return NULL; |
| 3240 | |
| 3241 | /* Handle GNU/Linux's syscall SIGTRAPs. */ |
| 3242 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP) |
| 3243 | { |
| 3244 | /* No longer need the sysgood bit. The ptrace event ends up |
| 3245 | recorded in lp->waitstatus if we care for it. We can carry |
| 3246 | on handling the event like a regular SIGTRAP from here |
| 3247 | on. */ |
| 3248 | status = W_STOPCODE (SIGTRAP); |
| 3249 | if (linux_handle_syscall_trap (lp, 0)) |
| 3250 | return NULL; |
| 3251 | } |
| 3252 | |
| 3253 | /* Handle GNU/Linux's extended waitstatus for trace events. */ |
| 3254 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0) |
| 3255 | { |
| 3256 | if (debug_linux_nat) |
| 3257 | fprintf_unfiltered (gdb_stdlog, |
| 3258 | "LLW: Handling extended status 0x%06x\n", |
| 3259 | status); |
| 3260 | if (linux_handle_extended_wait (lp, status, 0)) |
| 3261 | return NULL; |
| 3262 | } |
| 3263 | |
| 3264 | if (linux_nat_status_is_event (status)) |
| 3265 | save_sigtrap (lp); |
| 3266 | |
| 3267 | /* Check if the thread has exited. */ |
| 3268 | if ((WIFEXITED (status) || WIFSIGNALED (status)) |
| 3269 | && num_lwps (GET_PID (lp->ptid)) > 1) |
| 3270 | { |
| 3271 | /* If this is the main thread, we must stop all threads and verify |
| 3272 | if they are still alive. This is because in the nptl thread model |
| 3273 | on Linux 2.4, there is no signal issued for exiting LWPs |
| 3274 | other than the main thread. We only get the main thread exit |
| 3275 | signal once all child threads have already exited. If we |
| 3276 | stop all the threads and use the stop_wait_callback to check |
| 3277 | if they have exited we can determine whether this signal |
| 3278 | should be ignored or whether it means the end of the debugged |
| 3279 | application, regardless of which threading model is being |
| 3280 | used. */ |
| 3281 | if (GET_PID (lp->ptid) == GET_LWP (lp->ptid)) |
| 3282 | { |
| 3283 | lp->stopped = 1; |
| 3284 | iterate_over_lwps (pid_to_ptid (GET_PID (lp->ptid)), |
| 3285 | stop_and_resume_callback, new_pending_p); |
| 3286 | } |
| 3287 | |
| 3288 | if (debug_linux_nat) |
| 3289 | fprintf_unfiltered (gdb_stdlog, |
| 3290 | "LLW: %s exited.\n", |
| 3291 | target_pid_to_str (lp->ptid)); |
| 3292 | |
| 3293 | if (num_lwps (GET_PID (lp->ptid)) > 1) |
| 3294 | { |
| 3295 | /* If there is at least one more LWP, then the exit signal |
| 3296 | was not the end of the debugged application and should be |
| 3297 | ignored. */ |
| 3298 | exit_lwp (lp); |
| 3299 | return NULL; |
| 3300 | } |
| 3301 | } |
| 3302 | |
| 3303 | /* Check if the current LWP has previously exited. In the nptl |
| 3304 | thread model, LWPs other than the main thread do not issue |
| 3305 | signals when they exit so we must check whenever the thread has |
| 3306 | stopped. A similar check is made in stop_wait_callback(). */ |
| 3307 | if (num_lwps (GET_PID (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid)) |
| 3308 | { |
| 3309 | ptid_t ptid = pid_to_ptid (GET_PID (lp->ptid)); |
| 3310 | |
| 3311 | if (debug_linux_nat) |
| 3312 | fprintf_unfiltered (gdb_stdlog, |
| 3313 | "LLW: %s exited.\n", |
| 3314 | target_pid_to_str (lp->ptid)); |
| 3315 | |
| 3316 | exit_lwp (lp); |
| 3317 | |
| 3318 | /* Make sure there is at least one thread running. */ |
| 3319 | gdb_assert (iterate_over_lwps (ptid, running_callback, NULL)); |
| 3320 | |
| 3321 | /* Discard the event. */ |
| 3322 | return NULL; |
| 3323 | } |
| 3324 | |
| 3325 | /* Make sure we don't report a SIGSTOP that we sent ourselves in |
| 3326 | an attempt to stop an LWP. */ |
| 3327 | if (lp->signalled |
| 3328 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP) |
| 3329 | { |
| 3330 | if (debug_linux_nat) |
| 3331 | fprintf_unfiltered (gdb_stdlog, |
| 3332 | "LLW: Delayed SIGSTOP caught for %s.\n", |
| 3333 | target_pid_to_str (lp->ptid)); |
| 3334 | |
| 3335 | lp->signalled = 0; |
| 3336 | |
| 3337 | if (lp->last_resume_kind != resume_stop) |
| 3338 | { |
| 3339 | /* This is a delayed SIGSTOP. */ |
| 3340 | |
| 3341 | registers_changed (); |
| 3342 | |
| 3343 | if (linux_nat_prepare_to_resume != NULL) |
| 3344 | linux_nat_prepare_to_resume (lp); |
| 3345 | linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)), |
| 3346 | lp->step, GDB_SIGNAL_0); |
| 3347 | if (debug_linux_nat) |
| 3348 | fprintf_unfiltered (gdb_stdlog, |
| 3349 | "LLW: %s %s, 0, 0 (discard SIGSTOP)\n", |
| 3350 | lp->step ? |
| 3351 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
| 3352 | target_pid_to_str (lp->ptid)); |
| 3353 | |
| 3354 | lp->stopped = 0; |
| 3355 | gdb_assert (lp->resumed); |
| 3356 | |
| 3357 | /* Discard the event. */ |
| 3358 | return NULL; |
| 3359 | } |
| 3360 | } |
| 3361 | |
| 3362 | /* Make sure we don't report a SIGINT that we have already displayed |
| 3363 | for another thread. */ |
| 3364 | if (lp->ignore_sigint |
| 3365 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT) |
| 3366 | { |
| 3367 | if (debug_linux_nat) |
| 3368 | fprintf_unfiltered (gdb_stdlog, |
| 3369 | "LLW: Delayed SIGINT caught for %s.\n", |
| 3370 | target_pid_to_str (lp->ptid)); |
| 3371 | |
| 3372 | /* This is a delayed SIGINT. */ |
| 3373 | lp->ignore_sigint = 0; |
| 3374 | |
| 3375 | registers_changed (); |
| 3376 | if (linux_nat_prepare_to_resume != NULL) |
| 3377 | linux_nat_prepare_to_resume (lp); |
| 3378 | linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)), |
| 3379 | lp->step, GDB_SIGNAL_0); |
| 3380 | if (debug_linux_nat) |
| 3381 | fprintf_unfiltered (gdb_stdlog, |
| 3382 | "LLW: %s %s, 0, 0 (discard SIGINT)\n", |
| 3383 | lp->step ? |
| 3384 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
| 3385 | target_pid_to_str (lp->ptid)); |
| 3386 | |
| 3387 | lp->stopped = 0; |
| 3388 | gdb_assert (lp->resumed); |
| 3389 | |
| 3390 | /* Discard the event. */ |
| 3391 | return NULL; |
| 3392 | } |
| 3393 | |
| 3394 | /* An interesting event. */ |
| 3395 | gdb_assert (lp); |
| 3396 | lp->status = status; |
| 3397 | return lp; |
| 3398 | } |
| 3399 | |
| 3400 | /* Detect zombie thread group leaders, and "exit" them. We can't reap |
| 3401 | their exits until all other threads in the group have exited. */ |
| 3402 | |
| 3403 | static void |
| 3404 | check_zombie_leaders (void) |
| 3405 | { |
| 3406 | struct inferior *inf; |
| 3407 | |
| 3408 | ALL_INFERIORS (inf) |
| 3409 | { |
| 3410 | struct lwp_info *leader_lp; |
| 3411 | |
| 3412 | if (inf->pid == 0) |
| 3413 | continue; |
| 3414 | |
| 3415 | leader_lp = find_lwp_pid (pid_to_ptid (inf->pid)); |
| 3416 | if (leader_lp != NULL |
| 3417 | /* Check if there are other threads in the group, as we may |
| 3418 | have raced with the inferior simply exiting. */ |
| 3419 | && num_lwps (inf->pid) > 1 |
| 3420 | && linux_proc_pid_is_zombie (inf->pid)) |
| 3421 | { |
| 3422 | if (debug_linux_nat) |
| 3423 | fprintf_unfiltered (gdb_stdlog, |
| 3424 | "CZL: Thread group leader %d zombie " |
| 3425 | "(it exited, or another thread execd).\n", |
| 3426 | inf->pid); |
| 3427 | |
| 3428 | /* A leader zombie can mean one of two things: |
| 3429 | |
| 3430 | - It exited, and there's an exit status pending |
| 3431 | available, or only the leader exited (not the whole |
| 3432 | program). In the latter case, we can't waitpid the |
| 3433 | leader's exit status until all other threads are gone. |
| 3434 | |
| 3435 | - There are 3 or more threads in the group, and a thread |
| 3436 | other than the leader exec'd. On an exec, the Linux |
| 3437 | kernel destroys all other threads (except the execing |
| 3438 | one) in the thread group, and resets the execing thread's |
| 3439 | tid to the tgid. No exit notification is sent for the |
| 3440 | execing thread -- from the ptracer's perspective, it |
| 3441 | appears as though the execing thread just vanishes. |
| 3442 | Until we reap all other threads except the leader and the |
| 3443 | execing thread, the leader will be zombie, and the |
| 3444 | execing thread will be in `D (disc sleep)'. As soon as |
| 3445 | all other threads are reaped, the execing thread changes |
| 3446 | it's tid to the tgid, and the previous (zombie) leader |
| 3447 | vanishes, giving place to the "new" leader. We could try |
| 3448 | distinguishing the exit and exec cases, by waiting once |
| 3449 | more, and seeing if something comes out, but it doesn't |
| 3450 | sound useful. The previous leader _does_ go away, and |
| 3451 | we'll re-add the new one once we see the exec event |
| 3452 | (which is just the same as what would happen if the |
| 3453 | previous leader did exit voluntarily before some other |
| 3454 | thread execs). */ |
| 3455 | |
| 3456 | if (debug_linux_nat) |
| 3457 | fprintf_unfiltered (gdb_stdlog, |
| 3458 | "CZL: Thread group leader %d vanished.\n", |
| 3459 | inf->pid); |
| 3460 | exit_lwp (leader_lp); |
| 3461 | } |
| 3462 | } |
| 3463 | } |
| 3464 | |
| 3465 | static ptid_t |
| 3466 | linux_nat_wait_1 (struct target_ops *ops, |
| 3467 | ptid_t ptid, struct target_waitstatus *ourstatus, |
| 3468 | int target_options) |
| 3469 | { |
| 3470 | static sigset_t prev_mask; |
| 3471 | enum resume_kind last_resume_kind; |
| 3472 | struct lwp_info *lp; |
| 3473 | int status; |
| 3474 | |
| 3475 | if (debug_linux_nat) |
| 3476 | fprintf_unfiltered (gdb_stdlog, "LLW: enter\n"); |
| 3477 | |
| 3478 | /* The first time we get here after starting a new inferior, we may |
| 3479 | not have added it to the LWP list yet - this is the earliest |
| 3480 | moment at which we know its PID. */ |
| 3481 | if (ptid_is_pid (inferior_ptid)) |
| 3482 | { |
| 3483 | /* Upgrade the main thread's ptid. */ |
| 3484 | thread_change_ptid (inferior_ptid, |
| 3485 | BUILD_LWP (GET_PID (inferior_ptid), |
| 3486 | GET_PID (inferior_ptid))); |
| 3487 | |
| 3488 | lp = add_lwp (inferior_ptid); |
| 3489 | lp->resumed = 1; |
| 3490 | } |
| 3491 | |
| 3492 | /* Make sure SIGCHLD is blocked. */ |
| 3493 | block_child_signals (&prev_mask); |
| 3494 | |
| 3495 | retry: |
| 3496 | lp = NULL; |
| 3497 | status = 0; |
| 3498 | |
| 3499 | /* First check if there is a LWP with a wait status pending. */ |
| 3500 | if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid)) |
| 3501 | { |
| 3502 | /* Any LWP in the PTID group that's been resumed will do. */ |
| 3503 | lp = iterate_over_lwps (ptid, status_callback, NULL); |
| 3504 | if (lp) |
| 3505 | { |
| 3506 | if (debug_linux_nat && lp->status) |
| 3507 | fprintf_unfiltered (gdb_stdlog, |
| 3508 | "LLW: Using pending wait status %s for %s.\n", |
| 3509 | status_to_str (lp->status), |
| 3510 | target_pid_to_str (lp->ptid)); |
| 3511 | } |
| 3512 | } |
| 3513 | else if (is_lwp (ptid)) |
| 3514 | { |
| 3515 | if (debug_linux_nat) |
| 3516 | fprintf_unfiltered (gdb_stdlog, |
| 3517 | "LLW: Waiting for specific LWP %s.\n", |
| 3518 | target_pid_to_str (ptid)); |
| 3519 | |
| 3520 | /* We have a specific LWP to check. */ |
| 3521 | lp = find_lwp_pid (ptid); |
| 3522 | gdb_assert (lp); |
| 3523 | |
| 3524 | if (debug_linux_nat && lp->status) |
| 3525 | fprintf_unfiltered (gdb_stdlog, |
| 3526 | "LLW: Using pending wait status %s for %s.\n", |
| 3527 | status_to_str (lp->status), |
| 3528 | target_pid_to_str (lp->ptid)); |
| 3529 | |
| 3530 | /* We check for lp->waitstatus in addition to lp->status, |
| 3531 | because we can have pending process exits recorded in |
| 3532 | lp->status and W_EXITCODE(0,0) == 0. We should probably have |
| 3533 | an additional lp->status_p flag. */ |
| 3534 | if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE) |
| 3535 | lp = NULL; |
| 3536 | } |
| 3537 | |
| 3538 | if (!target_can_async_p ()) |
| 3539 | { |
| 3540 | /* Causes SIGINT to be passed on to the attached process. */ |
| 3541 | set_sigint_trap (); |
| 3542 | } |
| 3543 | |
| 3544 | /* But if we don't find a pending event, we'll have to wait. */ |
| 3545 | |
| 3546 | while (lp == NULL) |
| 3547 | { |
| 3548 | pid_t lwpid; |
| 3549 | |
| 3550 | /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace |
| 3551 | quirks: |
| 3552 | |
| 3553 | - If the thread group leader exits while other threads in the |
| 3554 | thread group still exist, waitpid(TGID, ...) hangs. That |
| 3555 | waitpid won't return an exit status until the other threads |
| 3556 | in the group are reapped. |
| 3557 | |
| 3558 | - When a non-leader thread execs, that thread just vanishes |
| 3559 | without reporting an exit (so we'd hang if we waited for it |
| 3560 | explicitly in that case). The exec event is reported to |
| 3561 | the TGID pid. */ |
| 3562 | |
| 3563 | errno = 0; |
| 3564 | lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG); |
| 3565 | if (lwpid == 0 || (lwpid == -1 && errno == ECHILD)) |
| 3566 | lwpid = my_waitpid (-1, &status, WNOHANG); |
| 3567 | |
| 3568 | if (debug_linux_nat) |
| 3569 | fprintf_unfiltered (gdb_stdlog, |
| 3570 | "LNW: waitpid(-1, ...) returned %d, %s\n", |
| 3571 | lwpid, errno ? safe_strerror (errno) : "ERRNO-OK"); |
| 3572 | |
| 3573 | if (lwpid > 0) |
| 3574 | { |
| 3575 | /* If this is true, then we paused LWPs momentarily, and may |
| 3576 | now have pending events to handle. */ |
| 3577 | int new_pending; |
| 3578 | |
| 3579 | if (debug_linux_nat) |
| 3580 | { |
| 3581 | fprintf_unfiltered (gdb_stdlog, |
| 3582 | "LLW: waitpid %ld received %s\n", |
| 3583 | (long) lwpid, status_to_str (status)); |
| 3584 | } |
| 3585 | |
| 3586 | lp = linux_nat_filter_event (lwpid, status, &new_pending); |
| 3587 | |
| 3588 | /* STATUS is now no longer valid, use LP->STATUS instead. */ |
| 3589 | status = 0; |
| 3590 | |
| 3591 | if (lp && !ptid_match (lp->ptid, ptid)) |
| 3592 | { |
| 3593 | gdb_assert (lp->resumed); |
| 3594 | |
| 3595 | if (debug_linux_nat) |
| 3596 | fprintf (stderr, |
| 3597 | "LWP %ld got an event %06x, leaving pending.\n", |
| 3598 | ptid_get_lwp (lp->ptid), lp->status); |
| 3599 | |
| 3600 | if (WIFSTOPPED (lp->status)) |
| 3601 | { |
| 3602 | if (WSTOPSIG (lp->status) != SIGSTOP) |
| 3603 | { |
| 3604 | /* Cancel breakpoint hits. The breakpoint may |
| 3605 | be removed before we fetch events from this |
| 3606 | process to report to the core. It is best |
| 3607 | not to assume the moribund breakpoints |
| 3608 | heuristic always handles these cases --- it |
| 3609 | could be too many events go through to the |
| 3610 | core before this one is handled. All-stop |
| 3611 | always cancels breakpoint hits in all |
| 3612 | threads. */ |
| 3613 | if (non_stop |
| 3614 | && linux_nat_lp_status_is_event (lp) |
| 3615 | && cancel_breakpoint (lp)) |
| 3616 | { |
| 3617 | /* Throw away the SIGTRAP. */ |
| 3618 | lp->status = 0; |
| 3619 | |
| 3620 | if (debug_linux_nat) |
| 3621 | fprintf (stderr, |
| 3622 | "LLW: LWP %ld hit a breakpoint while" |
| 3623 | " waiting for another process;" |
| 3624 | " cancelled it\n", |
| 3625 | ptid_get_lwp (lp->ptid)); |
| 3626 | } |
| 3627 | lp->stopped = 1; |
| 3628 | } |
| 3629 | else |
| 3630 | { |
| 3631 | lp->stopped = 1; |
| 3632 | lp->signalled = 0; |
| 3633 | } |
| 3634 | } |
| 3635 | else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status)) |
| 3636 | { |
| 3637 | if (debug_linux_nat) |
| 3638 | fprintf (stderr, |
| 3639 | "Process %ld exited while stopping LWPs\n", |
| 3640 | ptid_get_lwp (lp->ptid)); |
| 3641 | |
| 3642 | /* This was the last lwp in the process. Since |
| 3643 | events are serialized to GDB core, and we can't |
| 3644 | report this one right now, but GDB core and the |
| 3645 | other target layers will want to be notified |
| 3646 | about the exit code/signal, leave the status |
| 3647 | pending for the next time we're able to report |
| 3648 | it. */ |
| 3649 | |
| 3650 | /* Prevent trying to stop this thread again. We'll |
| 3651 | never try to resume it because it has a pending |
| 3652 | status. */ |
| 3653 | lp->stopped = 1; |
| 3654 | |
| 3655 | /* Dead LWP's aren't expected to reported a pending |
| 3656 | sigstop. */ |
| 3657 | lp->signalled = 0; |
| 3658 | |
| 3659 | /* Store the pending event in the waitstatus as |
| 3660 | well, because W_EXITCODE(0,0) == 0. */ |
| 3661 | store_waitstatus (&lp->waitstatus, lp->status); |
| 3662 | } |
| 3663 | |
| 3664 | /* Keep looking. */ |
| 3665 | lp = NULL; |
| 3666 | } |
| 3667 | |
| 3668 | if (new_pending) |
| 3669 | { |
| 3670 | /* Some LWP now has a pending event. Go all the way |
| 3671 | back to check it. */ |
| 3672 | goto retry; |
| 3673 | } |
| 3674 | |
| 3675 | if (lp) |
| 3676 | { |
| 3677 | /* We got an event to report to the core. */ |
| 3678 | break; |
| 3679 | } |
| 3680 | |
| 3681 | /* Retry until nothing comes out of waitpid. A single |
| 3682 | SIGCHLD can indicate more than one child stopped. */ |
| 3683 | continue; |
| 3684 | } |
| 3685 | |
| 3686 | /* Check for zombie thread group leaders. Those can't be reaped |
| 3687 | until all other threads in the thread group are. */ |
| 3688 | check_zombie_leaders (); |
| 3689 | |
| 3690 | /* If there are no resumed children left, bail. We'd be stuck |
| 3691 | forever in the sigsuspend call below otherwise. */ |
| 3692 | if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL) |
| 3693 | { |
| 3694 | if (debug_linux_nat) |
| 3695 | fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n"); |
| 3696 | |
| 3697 | ourstatus->kind = TARGET_WAITKIND_NO_RESUMED; |
| 3698 | |
| 3699 | if (!target_can_async_p ()) |
| 3700 | clear_sigint_trap (); |
| 3701 | |
| 3702 | restore_child_signals_mask (&prev_mask); |
| 3703 | return minus_one_ptid; |
| 3704 | } |
| 3705 | |
| 3706 | /* No interesting event to report to the core. */ |
| 3707 | |
| 3708 | if (target_options & TARGET_WNOHANG) |
| 3709 | { |
| 3710 | if (debug_linux_nat) |
| 3711 | fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n"); |
| 3712 | |
| 3713 | ourstatus->kind = TARGET_WAITKIND_IGNORE; |
| 3714 | restore_child_signals_mask (&prev_mask); |
| 3715 | return minus_one_ptid; |
| 3716 | } |
| 3717 | |
| 3718 | /* We shouldn't end up here unless we want to try again. */ |
| 3719 | gdb_assert (lp == NULL); |
| 3720 | |
| 3721 | /* Block until we get an event reported with SIGCHLD. */ |
| 3722 | sigsuspend (&suspend_mask); |
| 3723 | } |
| 3724 | |
| 3725 | if (!target_can_async_p ()) |
| 3726 | clear_sigint_trap (); |
| 3727 | |
| 3728 | gdb_assert (lp); |
| 3729 | |
| 3730 | status = lp->status; |
| 3731 | lp->status = 0; |
| 3732 | |
| 3733 | /* Don't report signals that GDB isn't interested in, such as |
| 3734 | signals that are neither printed nor stopped upon. Stopping all |
| 3735 | threads can be a bit time-consuming so if we want decent |
| 3736 | performance with heavily multi-threaded programs, especially when |
| 3737 | they're using a high frequency timer, we'd better avoid it if we |
| 3738 | can. */ |
| 3739 | |
| 3740 | if (WIFSTOPPED (status)) |
| 3741 | { |
| 3742 | enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status)); |
| 3743 | |
| 3744 | /* When using hardware single-step, we need to report every signal. |
| 3745 | Otherwise, signals in pass_mask may be short-circuited. */ |
| 3746 | if (!lp->step |
| 3747 | && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))) |
| 3748 | { |
| 3749 | /* FIMXE: kettenis/2001-06-06: Should we resume all threads |
| 3750 | here? It is not clear we should. GDB may not expect |
| 3751 | other threads to run. On the other hand, not resuming |
| 3752 | newly attached threads may cause an unwanted delay in |
| 3753 | getting them running. */ |
| 3754 | registers_changed (); |
| 3755 | if (linux_nat_prepare_to_resume != NULL) |
| 3756 | linux_nat_prepare_to_resume (lp); |
| 3757 | linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)), |
| 3758 | lp->step, signo); |
| 3759 | if (debug_linux_nat) |
| 3760 | fprintf_unfiltered (gdb_stdlog, |
| 3761 | "LLW: %s %s, %s (preempt 'handle')\n", |
| 3762 | lp->step ? |
| 3763 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
| 3764 | target_pid_to_str (lp->ptid), |
| 3765 | (signo != GDB_SIGNAL_0 |
| 3766 | ? strsignal (gdb_signal_to_host (signo)) |
| 3767 | : "0")); |
| 3768 | lp->stopped = 0; |
| 3769 | goto retry; |
| 3770 | } |
| 3771 | |
| 3772 | if (!non_stop) |
| 3773 | { |
| 3774 | /* Only do the below in all-stop, as we currently use SIGINT |
| 3775 | to implement target_stop (see linux_nat_stop) in |
| 3776 | non-stop. */ |
| 3777 | if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0) |
| 3778 | { |
| 3779 | /* If ^C/BREAK is typed at the tty/console, SIGINT gets |
| 3780 | forwarded to the entire process group, that is, all LWPs |
| 3781 | will receive it - unless they're using CLONE_THREAD to |
| 3782 | share signals. Since we only want to report it once, we |
| 3783 | mark it as ignored for all LWPs except this one. */ |
| 3784 | iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)), |
| 3785 | set_ignore_sigint, NULL); |
| 3786 | lp->ignore_sigint = 0; |
| 3787 | } |
| 3788 | else |
| 3789 | maybe_clear_ignore_sigint (lp); |
| 3790 | } |
| 3791 | } |
| 3792 | |
| 3793 | /* This LWP is stopped now. */ |
| 3794 | lp->stopped = 1; |
| 3795 | |
| 3796 | if (debug_linux_nat) |
| 3797 | fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n", |
| 3798 | status_to_str (status), target_pid_to_str (lp->ptid)); |
| 3799 | |
| 3800 | if (!non_stop) |
| 3801 | { |
| 3802 | /* Now stop all other LWP's ... */ |
| 3803 | iterate_over_lwps (minus_one_ptid, stop_callback, NULL); |
| 3804 | |
| 3805 | /* ... and wait until all of them have reported back that |
| 3806 | they're no longer running. */ |
| 3807 | iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL); |
| 3808 | |
| 3809 | /* If we're not waiting for a specific LWP, choose an event LWP |
| 3810 | from among those that have had events. Giving equal priority |
| 3811 | to all LWPs that have had events helps prevent |
| 3812 | starvation. */ |
| 3813 | if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid)) |
| 3814 | select_event_lwp (ptid, &lp, &status); |
| 3815 | |
| 3816 | /* Now that we've selected our final event LWP, cancel any |
| 3817 | breakpoints in other LWPs that have hit a GDB breakpoint. |
| 3818 | See the comment in cancel_breakpoints_callback to find out |
| 3819 | why. */ |
| 3820 | iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp); |
| 3821 | |
| 3822 | /* We'll need this to determine whether to report a SIGSTOP as |
| 3823 | TARGET_WAITKIND_0. Need to take a copy because |
| 3824 | resume_clear_callback clears it. */ |
| 3825 | last_resume_kind = lp->last_resume_kind; |
| 3826 | |
| 3827 | /* In all-stop, from the core's perspective, all LWPs are now |
| 3828 | stopped until a new resume action is sent over. */ |
| 3829 | iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL); |
| 3830 | } |
| 3831 | else |
| 3832 | { |
| 3833 | /* See above. */ |
| 3834 | last_resume_kind = lp->last_resume_kind; |
| 3835 | resume_clear_callback (lp, NULL); |
| 3836 | } |
| 3837 | |
| 3838 | if (linux_nat_status_is_event (status)) |
| 3839 | { |
| 3840 | if (debug_linux_nat) |
| 3841 | fprintf_unfiltered (gdb_stdlog, |
| 3842 | "LLW: trap ptid is %s.\n", |
| 3843 | target_pid_to_str (lp->ptid)); |
| 3844 | } |
| 3845 | |
| 3846 | if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE) |
| 3847 | { |
| 3848 | *ourstatus = lp->waitstatus; |
| 3849 | lp->waitstatus.kind = TARGET_WAITKIND_IGNORE; |
| 3850 | } |
| 3851 | else |
| 3852 | store_waitstatus (ourstatus, status); |
| 3853 | |
| 3854 | if (debug_linux_nat) |
| 3855 | fprintf_unfiltered (gdb_stdlog, "LLW: exit\n"); |
| 3856 | |
| 3857 | restore_child_signals_mask (&prev_mask); |
| 3858 | |
| 3859 | if (last_resume_kind == resume_stop |
| 3860 | && ourstatus->kind == TARGET_WAITKIND_STOPPED |
| 3861 | && WSTOPSIG (status) == SIGSTOP) |
| 3862 | { |
| 3863 | /* A thread that has been requested to stop by GDB with |
| 3864 | target_stop, and it stopped cleanly, so report as SIG0. The |
| 3865 | use of SIGSTOP is an implementation detail. */ |
| 3866 | ourstatus->value.sig = GDB_SIGNAL_0; |
| 3867 | } |
| 3868 | |
| 3869 | if (ourstatus->kind == TARGET_WAITKIND_EXITED |
| 3870 | || ourstatus->kind == TARGET_WAITKIND_SIGNALLED) |
| 3871 | lp->core = -1; |
| 3872 | else |
| 3873 | lp->core = linux_common_core_of_thread (lp->ptid); |
| 3874 | |
| 3875 | return lp->ptid; |
| 3876 | } |
| 3877 | |
| 3878 | /* Resume LWPs that are currently stopped without any pending status |
| 3879 | to report, but are resumed from the core's perspective. */ |
| 3880 | |
| 3881 | static int |
| 3882 | resume_stopped_resumed_lwps (struct lwp_info *lp, void *data) |
| 3883 | { |
| 3884 | ptid_t *wait_ptid_p = data; |
| 3885 | |
| 3886 | if (lp->stopped |
| 3887 | && lp->resumed |
| 3888 | && lp->status == 0 |
| 3889 | && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE) |
| 3890 | { |
| 3891 | struct regcache *regcache = get_thread_regcache (lp->ptid); |
| 3892 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 3893 | CORE_ADDR pc = regcache_read_pc (regcache); |
| 3894 | |
| 3895 | gdb_assert (is_executing (lp->ptid)); |
| 3896 | |
| 3897 | /* Don't bother if there's a breakpoint at PC that we'd hit |
| 3898 | immediately, and we're not waiting for this LWP. */ |
| 3899 | if (!ptid_match (lp->ptid, *wait_ptid_p)) |
| 3900 | { |
| 3901 | if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc)) |
| 3902 | return 0; |
| 3903 | } |
| 3904 | |
| 3905 | if (debug_linux_nat) |
| 3906 | fprintf_unfiltered (gdb_stdlog, |
| 3907 | "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n", |
| 3908 | target_pid_to_str (lp->ptid), |
| 3909 | paddress (gdbarch, pc), |
| 3910 | lp->step); |
| 3911 | |
| 3912 | registers_changed (); |
| 3913 | if (linux_nat_prepare_to_resume != NULL) |
| 3914 | linux_nat_prepare_to_resume (lp); |
| 3915 | linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)), |
| 3916 | lp->step, GDB_SIGNAL_0); |
| 3917 | lp->stopped = 0; |
| 3918 | lp->stopped_by_watchpoint = 0; |
| 3919 | } |
| 3920 | |
| 3921 | return 0; |
| 3922 | } |
| 3923 | |
| 3924 | static ptid_t |
| 3925 | linux_nat_wait (struct target_ops *ops, |
| 3926 | ptid_t ptid, struct target_waitstatus *ourstatus, |
| 3927 | int target_options) |
| 3928 | { |
| 3929 | ptid_t event_ptid; |
| 3930 | |
| 3931 | if (debug_linux_nat) |
| 3932 | fprintf_unfiltered (gdb_stdlog, |
| 3933 | "linux_nat_wait: [%s]\n", target_pid_to_str (ptid)); |
| 3934 | |
| 3935 | /* Flush the async file first. */ |
| 3936 | if (target_can_async_p ()) |
| 3937 | async_file_flush (); |
| 3938 | |
| 3939 | /* Resume LWPs that are currently stopped without any pending status |
| 3940 | to report, but are resumed from the core's perspective. LWPs get |
| 3941 | in this state if we find them stopping at a time we're not |
| 3942 | interested in reporting the event (target_wait on a |
| 3943 | specific_process, for example, see linux_nat_wait_1), and |
| 3944 | meanwhile the event became uninteresting. Don't bother resuming |
| 3945 | LWPs we're not going to wait for if they'd stop immediately. */ |
| 3946 | if (non_stop) |
| 3947 | iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid); |
| 3948 | |
| 3949 | event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options); |
| 3950 | |
| 3951 | /* If we requested any event, and something came out, assume there |
| 3952 | may be more. If we requested a specific lwp or process, also |
| 3953 | assume there may be more. */ |
| 3954 | if (target_can_async_p () |
| 3955 | && ((ourstatus->kind != TARGET_WAITKIND_IGNORE |
| 3956 | && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED) |
| 3957 | || !ptid_equal (ptid, minus_one_ptid))) |
| 3958 | async_file_mark (); |
| 3959 | |
| 3960 | /* Get ready for the next event. */ |
| 3961 | if (target_can_async_p ()) |
| 3962 | target_async (inferior_event_handler, 0); |
| 3963 | |
| 3964 | return event_ptid; |
| 3965 | } |
| 3966 | |
| 3967 | static int |
| 3968 | kill_callback (struct lwp_info *lp, void *data) |
| 3969 | { |
| 3970 | /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */ |
| 3971 | |
| 3972 | errno = 0; |
| 3973 | kill (GET_LWP (lp->ptid), SIGKILL); |
| 3974 | if (debug_linux_nat) |
| 3975 | fprintf_unfiltered (gdb_stdlog, |
| 3976 | "KC: kill (SIGKILL) %s, 0, 0 (%s)\n", |
| 3977 | target_pid_to_str (lp->ptid), |
| 3978 | errno ? safe_strerror (errno) : "OK"); |
| 3979 | |
| 3980 | /* Some kernels ignore even SIGKILL for processes under ptrace. */ |
| 3981 | |
| 3982 | errno = 0; |
| 3983 | ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0); |
| 3984 | if (debug_linux_nat) |
| 3985 | fprintf_unfiltered (gdb_stdlog, |
| 3986 | "KC: PTRACE_KILL %s, 0, 0 (%s)\n", |
| 3987 | target_pid_to_str (lp->ptid), |
| 3988 | errno ? safe_strerror (errno) : "OK"); |
| 3989 | |
| 3990 | return 0; |
| 3991 | } |
| 3992 | |
| 3993 | static int |
| 3994 | kill_wait_callback (struct lwp_info *lp, void *data) |
| 3995 | { |
| 3996 | pid_t pid; |
| 3997 | |
| 3998 | /* We must make sure that there are no pending events (delayed |
| 3999 | SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current |
| 4000 | program doesn't interfere with any following debugging session. */ |
| 4001 | |
| 4002 | /* For cloned processes we must check both with __WCLONE and |
| 4003 | without, since the exit status of a cloned process isn't reported |
| 4004 | with __WCLONE. */ |
| 4005 | if (lp->cloned) |
| 4006 | { |
| 4007 | do |
| 4008 | { |
| 4009 | pid = my_waitpid (GET_LWP (lp->ptid), NULL, __WCLONE); |
| 4010 | if (pid != (pid_t) -1) |
| 4011 | { |
| 4012 | if (debug_linux_nat) |
| 4013 | fprintf_unfiltered (gdb_stdlog, |
| 4014 | "KWC: wait %s received unknown.\n", |
| 4015 | target_pid_to_str (lp->ptid)); |
| 4016 | /* The Linux kernel sometimes fails to kill a thread |
| 4017 | completely after PTRACE_KILL; that goes from the stop |
| 4018 | point in do_fork out to the one in |
| 4019 | get_signal_to_deliever and waits again. So kill it |
| 4020 | again. */ |
| 4021 | kill_callback (lp, NULL); |
| 4022 | } |
| 4023 | } |
| 4024 | while (pid == GET_LWP (lp->ptid)); |
| 4025 | |
| 4026 | gdb_assert (pid == -1 && errno == ECHILD); |
| 4027 | } |
| 4028 | |
| 4029 | do |
| 4030 | { |
| 4031 | pid = my_waitpid (GET_LWP (lp->ptid), NULL, 0); |
| 4032 | if (pid != (pid_t) -1) |
| 4033 | { |
| 4034 | if (debug_linux_nat) |
| 4035 | fprintf_unfiltered (gdb_stdlog, |
| 4036 | "KWC: wait %s received unk.\n", |
| 4037 | target_pid_to_str (lp->ptid)); |
| 4038 | /* See the call to kill_callback above. */ |
| 4039 | kill_callback (lp, NULL); |
| 4040 | } |
| 4041 | } |
| 4042 | while (pid == GET_LWP (lp->ptid)); |
| 4043 | |
| 4044 | gdb_assert (pid == -1 && errno == ECHILD); |
| 4045 | return 0; |
| 4046 | } |
| 4047 | |
| 4048 | static void |
| 4049 | linux_nat_kill (struct target_ops *ops) |
| 4050 | { |
| 4051 | struct target_waitstatus last; |
| 4052 | ptid_t last_ptid; |
| 4053 | int status; |
| 4054 | |
| 4055 | /* If we're stopped while forking and we haven't followed yet, |
| 4056 | kill the other task. We need to do this first because the |
| 4057 | parent will be sleeping if this is a vfork. */ |
| 4058 | |
| 4059 | get_last_target_status (&last_ptid, &last); |
| 4060 | |
| 4061 | if (last.kind == TARGET_WAITKIND_FORKED |
| 4062 | || last.kind == TARGET_WAITKIND_VFORKED) |
| 4063 | { |
| 4064 | ptrace (PT_KILL, PIDGET (last.value.related_pid), 0, 0); |
| 4065 | wait (&status); |
| 4066 | } |
| 4067 | |
| 4068 | if (forks_exist_p ()) |
| 4069 | linux_fork_killall (); |
| 4070 | else |
| 4071 | { |
| 4072 | ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid)); |
| 4073 | |
| 4074 | /* Stop all threads before killing them, since ptrace requires |
| 4075 | that the thread is stopped to sucessfully PTRACE_KILL. */ |
| 4076 | iterate_over_lwps (ptid, stop_callback, NULL); |
| 4077 | /* ... and wait until all of them have reported back that |
| 4078 | they're no longer running. */ |
| 4079 | iterate_over_lwps (ptid, stop_wait_callback, NULL); |
| 4080 | |
| 4081 | /* Kill all LWP's ... */ |
| 4082 | iterate_over_lwps (ptid, kill_callback, NULL); |
| 4083 | |
| 4084 | /* ... and wait until we've flushed all events. */ |
| 4085 | iterate_over_lwps (ptid, kill_wait_callback, NULL); |
| 4086 | } |
| 4087 | |
| 4088 | target_mourn_inferior (); |
| 4089 | } |
| 4090 | |
| 4091 | static void |
| 4092 | linux_nat_mourn_inferior (struct target_ops *ops) |
| 4093 | { |
| 4094 | purge_lwp_list (ptid_get_pid (inferior_ptid)); |
| 4095 | |
| 4096 | if (! forks_exist_p ()) |
| 4097 | /* Normal case, no other forks available. */ |
| 4098 | linux_ops->to_mourn_inferior (ops); |
| 4099 | else |
| 4100 | /* Multi-fork case. The current inferior_ptid has exited, but |
| 4101 | there are other viable forks to debug. Delete the exiting |
| 4102 | one and context-switch to the first available. */ |
| 4103 | linux_fork_mourn_inferior (); |
| 4104 | } |
| 4105 | |
| 4106 | /* Convert a native/host siginfo object, into/from the siginfo in the |
| 4107 | layout of the inferiors' architecture. */ |
| 4108 | |
| 4109 | static void |
| 4110 | siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction) |
| 4111 | { |
| 4112 | int done = 0; |
| 4113 | |
| 4114 | if (linux_nat_siginfo_fixup != NULL) |
| 4115 | done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction); |
| 4116 | |
| 4117 | /* If there was no callback, or the callback didn't do anything, |
| 4118 | then just do a straight memcpy. */ |
| 4119 | if (!done) |
| 4120 | { |
| 4121 | if (direction == 1) |
| 4122 | memcpy (siginfo, inf_siginfo, sizeof (siginfo_t)); |
| 4123 | else |
| 4124 | memcpy (inf_siginfo, siginfo, sizeof (siginfo_t)); |
| 4125 | } |
| 4126 | } |
| 4127 | |
| 4128 | static LONGEST |
| 4129 | linux_xfer_siginfo (struct target_ops *ops, enum target_object object, |
| 4130 | const char *annex, gdb_byte *readbuf, |
| 4131 | const gdb_byte *writebuf, ULONGEST offset, LONGEST len) |
| 4132 | { |
| 4133 | int pid; |
| 4134 | siginfo_t siginfo; |
| 4135 | gdb_byte inf_siginfo[sizeof (siginfo_t)]; |
| 4136 | |
| 4137 | gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO); |
| 4138 | gdb_assert (readbuf || writebuf); |
| 4139 | |
| 4140 | pid = GET_LWP (inferior_ptid); |
| 4141 | if (pid == 0) |
| 4142 | pid = GET_PID (inferior_ptid); |
| 4143 | |
| 4144 | if (offset > sizeof (siginfo)) |
| 4145 | return -1; |
| 4146 | |
| 4147 | errno = 0; |
| 4148 | ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo); |
| 4149 | if (errno != 0) |
| 4150 | return -1; |
| 4151 | |
| 4152 | /* When GDB is built as a 64-bit application, ptrace writes into |
| 4153 | SIGINFO an object with 64-bit layout. Since debugging a 32-bit |
| 4154 | inferior with a 64-bit GDB should look the same as debugging it |
| 4155 | with a 32-bit GDB, we need to convert it. GDB core always sees |
| 4156 | the converted layout, so any read/write will have to be done |
| 4157 | post-conversion. */ |
| 4158 | siginfo_fixup (&siginfo, inf_siginfo, 0); |
| 4159 | |
| 4160 | if (offset + len > sizeof (siginfo)) |
| 4161 | len = sizeof (siginfo) - offset; |
| 4162 | |
| 4163 | if (readbuf != NULL) |
| 4164 | memcpy (readbuf, inf_siginfo + offset, len); |
| 4165 | else |
| 4166 | { |
| 4167 | memcpy (inf_siginfo + offset, writebuf, len); |
| 4168 | |
| 4169 | /* Convert back to ptrace layout before flushing it out. */ |
| 4170 | siginfo_fixup (&siginfo, inf_siginfo, 1); |
| 4171 | |
| 4172 | errno = 0; |
| 4173 | ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo); |
| 4174 | if (errno != 0) |
| 4175 | return -1; |
| 4176 | } |
| 4177 | |
| 4178 | return len; |
| 4179 | } |
| 4180 | |
| 4181 | static LONGEST |
| 4182 | linux_nat_xfer_partial (struct target_ops *ops, enum target_object object, |
| 4183 | const char *annex, gdb_byte *readbuf, |
| 4184 | const gdb_byte *writebuf, |
| 4185 | ULONGEST offset, LONGEST len) |
| 4186 | { |
| 4187 | struct cleanup *old_chain; |
| 4188 | LONGEST xfer; |
| 4189 | |
| 4190 | if (object == TARGET_OBJECT_SIGNAL_INFO) |
| 4191 | return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf, |
| 4192 | offset, len); |
| 4193 | |
| 4194 | /* The target is connected but no live inferior is selected. Pass |
| 4195 | this request down to a lower stratum (e.g., the executable |
| 4196 | file). */ |
| 4197 | if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid)) |
| 4198 | return 0; |
| 4199 | |
| 4200 | old_chain = save_inferior_ptid (); |
| 4201 | |
| 4202 | if (is_lwp (inferior_ptid)) |
| 4203 | inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid)); |
| 4204 | |
| 4205 | xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf, |
| 4206 | offset, len); |
| 4207 | |
| 4208 | do_cleanups (old_chain); |
| 4209 | return xfer; |
| 4210 | } |
| 4211 | |
| 4212 | static int |
| 4213 | linux_thread_alive (ptid_t ptid) |
| 4214 | { |
| 4215 | int err, tmp_errno; |
| 4216 | |
| 4217 | gdb_assert (is_lwp (ptid)); |
| 4218 | |
| 4219 | /* Send signal 0 instead of anything ptrace, because ptracing a |
| 4220 | running thread errors out claiming that the thread doesn't |
| 4221 | exist. */ |
| 4222 | err = kill_lwp (GET_LWP (ptid), 0); |
| 4223 | tmp_errno = errno; |
| 4224 | if (debug_linux_nat) |
| 4225 | fprintf_unfiltered (gdb_stdlog, |
| 4226 | "LLTA: KILL(SIG0) %s (%s)\n", |
| 4227 | target_pid_to_str (ptid), |
| 4228 | err ? safe_strerror (tmp_errno) : "OK"); |
| 4229 | |
| 4230 | if (err != 0) |
| 4231 | return 0; |
| 4232 | |
| 4233 | return 1; |
| 4234 | } |
| 4235 | |
| 4236 | static int |
| 4237 | linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid) |
| 4238 | { |
| 4239 | return linux_thread_alive (ptid); |
| 4240 | } |
| 4241 | |
| 4242 | static char * |
| 4243 | linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid) |
| 4244 | { |
| 4245 | static char buf[64]; |
| 4246 | |
| 4247 | if (is_lwp (ptid) |
| 4248 | && (GET_PID (ptid) != GET_LWP (ptid) |
| 4249 | || num_lwps (GET_PID (ptid)) > 1)) |
| 4250 | { |
| 4251 | snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid)); |
| 4252 | return buf; |
| 4253 | } |
| 4254 | |
| 4255 | return normal_pid_to_str (ptid); |
| 4256 | } |
| 4257 | |
| 4258 | static char * |
| 4259 | linux_nat_thread_name (struct thread_info *thr) |
| 4260 | { |
| 4261 | int pid = ptid_get_pid (thr->ptid); |
| 4262 | long lwp = ptid_get_lwp (thr->ptid); |
| 4263 | #define FORMAT "/proc/%d/task/%ld/comm" |
| 4264 | char buf[sizeof (FORMAT) + 30]; |
| 4265 | FILE *comm_file; |
| 4266 | char *result = NULL; |
| 4267 | |
| 4268 | snprintf (buf, sizeof (buf), FORMAT, pid, lwp); |
| 4269 | comm_file = fopen (buf, "r"); |
| 4270 | if (comm_file) |
| 4271 | { |
| 4272 | /* Not exported by the kernel, so we define it here. */ |
| 4273 | #define COMM_LEN 16 |
| 4274 | static char line[COMM_LEN + 1]; |
| 4275 | |
| 4276 | if (fgets (line, sizeof (line), comm_file)) |
| 4277 | { |
| 4278 | char *nl = strchr (line, '\n'); |
| 4279 | |
| 4280 | if (nl) |
| 4281 | *nl = '\0'; |
| 4282 | if (*line != '\0') |
| 4283 | result = line; |
| 4284 | } |
| 4285 | |
| 4286 | fclose (comm_file); |
| 4287 | } |
| 4288 | |
| 4289 | #undef COMM_LEN |
| 4290 | #undef FORMAT |
| 4291 | |
| 4292 | return result; |
| 4293 | } |
| 4294 | |
| 4295 | /* Accepts an integer PID; Returns a string representing a file that |
| 4296 | can be opened to get the symbols for the child process. */ |
| 4297 | |
| 4298 | static char * |
| 4299 | linux_child_pid_to_exec_file (int pid) |
| 4300 | { |
| 4301 | char *name1, *name2; |
| 4302 | |
| 4303 | name1 = xmalloc (MAXPATHLEN); |
| 4304 | name2 = xmalloc (MAXPATHLEN); |
| 4305 | make_cleanup (xfree, name1); |
| 4306 | make_cleanup (xfree, name2); |
| 4307 | memset (name2, 0, MAXPATHLEN); |
| 4308 | |
| 4309 | sprintf (name1, "/proc/%d/exe", pid); |
| 4310 | if (readlink (name1, name2, MAXPATHLEN) > 0) |
| 4311 | return name2; |
| 4312 | else |
| 4313 | return name1; |
| 4314 | } |
| 4315 | |
| 4316 | /* Records the thread's register state for the corefile note |
| 4317 | section. */ |
| 4318 | |
| 4319 | static char * |
| 4320 | linux_nat_collect_thread_registers (const struct regcache *regcache, |
| 4321 | ptid_t ptid, bfd *obfd, |
| 4322 | char *note_data, int *note_size, |
| 4323 | enum gdb_signal stop_signal) |
| 4324 | { |
| 4325 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 4326 | const struct regset *regset; |
| 4327 | int core_regset_p; |
| 4328 | gdb_gregset_t gregs; |
| 4329 | gdb_fpregset_t fpregs; |
| 4330 | |
| 4331 | core_regset_p = gdbarch_regset_from_core_section_p (gdbarch); |
| 4332 | |
| 4333 | if (core_regset_p |
| 4334 | && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg", |
| 4335 | sizeof (gregs))) |
| 4336 | != NULL && regset->collect_regset != NULL) |
| 4337 | regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs)); |
| 4338 | else |
| 4339 | fill_gregset (regcache, &gregs, -1); |
| 4340 | |
| 4341 | note_data = (char *) elfcore_write_prstatus |
| 4342 | (obfd, note_data, note_size, ptid_get_lwp (ptid), |
| 4343 | gdb_signal_to_host (stop_signal), &gregs); |
| 4344 | |
| 4345 | if (core_regset_p |
| 4346 | && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2", |
| 4347 | sizeof (fpregs))) |
| 4348 | != NULL && regset->collect_regset != NULL) |
| 4349 | regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs)); |
| 4350 | else |
| 4351 | fill_fpregset (regcache, &fpregs, -1); |
| 4352 | |
| 4353 | note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size, |
| 4354 | &fpregs, sizeof (fpregs)); |
| 4355 | |
| 4356 | return note_data; |
| 4357 | } |
| 4358 | |
| 4359 | /* Fills the "to_make_corefile_note" target vector. Builds the note |
| 4360 | section for a corefile, and returns it in a malloc buffer. */ |
| 4361 | |
| 4362 | static char * |
| 4363 | linux_nat_make_corefile_notes (bfd *obfd, int *note_size) |
| 4364 | { |
| 4365 | /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been |
| 4366 | converted to gdbarch_core_regset_sections, this function can go away. */ |
| 4367 | return linux_make_corefile_notes (target_gdbarch, obfd, note_size, |
| 4368 | linux_nat_collect_thread_registers); |
| 4369 | } |
| 4370 | |
| 4371 | /* Implement the to_xfer_partial interface for memory reads using the /proc |
| 4372 | filesystem. Because we can use a single read() call for /proc, this |
| 4373 | can be much more efficient than banging away at PTRACE_PEEKTEXT, |
| 4374 | but it doesn't support writes. */ |
| 4375 | |
| 4376 | static LONGEST |
| 4377 | linux_proc_xfer_partial (struct target_ops *ops, enum target_object object, |
| 4378 | const char *annex, gdb_byte *readbuf, |
| 4379 | const gdb_byte *writebuf, |
| 4380 | ULONGEST offset, LONGEST len) |
| 4381 | { |
| 4382 | LONGEST ret; |
| 4383 | int fd; |
| 4384 | char filename[64]; |
| 4385 | |
| 4386 | if (object != TARGET_OBJECT_MEMORY || !readbuf) |
| 4387 | return 0; |
| 4388 | |
| 4389 | /* Don't bother for one word. */ |
| 4390 | if (len < 3 * sizeof (long)) |
| 4391 | return 0; |
| 4392 | |
| 4393 | /* We could keep this file open and cache it - possibly one per |
| 4394 | thread. That requires some juggling, but is even faster. */ |
| 4395 | sprintf (filename, "/proc/%d/mem", PIDGET (inferior_ptid)); |
| 4396 | fd = open (filename, O_RDONLY | O_LARGEFILE); |
| 4397 | if (fd == -1) |
| 4398 | return 0; |
| 4399 | |
| 4400 | /* If pread64 is available, use it. It's faster if the kernel |
| 4401 | supports it (only one syscall), and it's 64-bit safe even on |
| 4402 | 32-bit platforms (for instance, SPARC debugging a SPARC64 |
| 4403 | application). */ |
| 4404 | #ifdef HAVE_PREAD64 |
| 4405 | if (pread64 (fd, readbuf, len, offset) != len) |
| 4406 | #else |
| 4407 | if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len) |
| 4408 | #endif |
| 4409 | ret = 0; |
| 4410 | else |
| 4411 | ret = len; |
| 4412 | |
| 4413 | close (fd); |
| 4414 | return ret; |
| 4415 | } |
| 4416 | |
| 4417 | |
| 4418 | /* Enumerate spufs IDs for process PID. */ |
| 4419 | static LONGEST |
| 4420 | spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, LONGEST len) |
| 4421 | { |
| 4422 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); |
| 4423 | LONGEST pos = 0; |
| 4424 | LONGEST written = 0; |
| 4425 | char path[128]; |
| 4426 | DIR *dir; |
| 4427 | struct dirent *entry; |
| 4428 | |
| 4429 | xsnprintf (path, sizeof path, "/proc/%d/fd", pid); |
| 4430 | dir = opendir (path); |
| 4431 | if (!dir) |
| 4432 | return -1; |
| 4433 | |
| 4434 | rewinddir (dir); |
| 4435 | while ((entry = readdir (dir)) != NULL) |
| 4436 | { |
| 4437 | struct stat st; |
| 4438 | struct statfs stfs; |
| 4439 | int fd; |
| 4440 | |
| 4441 | fd = atoi (entry->d_name); |
| 4442 | if (!fd) |
| 4443 | continue; |
| 4444 | |
| 4445 | xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd); |
| 4446 | if (stat (path, &st) != 0) |
| 4447 | continue; |
| 4448 | if (!S_ISDIR (st.st_mode)) |
| 4449 | continue; |
| 4450 | |
| 4451 | if (statfs (path, &stfs) != 0) |
| 4452 | continue; |
| 4453 | if (stfs.f_type != SPUFS_MAGIC) |
| 4454 | continue; |
| 4455 | |
| 4456 | if (pos >= offset && pos + 4 <= offset + len) |
| 4457 | { |
| 4458 | store_unsigned_integer (buf + pos - offset, 4, byte_order, fd); |
| 4459 | written += 4; |
| 4460 | } |
| 4461 | pos += 4; |
| 4462 | } |
| 4463 | |
| 4464 | closedir (dir); |
| 4465 | return written; |
| 4466 | } |
| 4467 | |
| 4468 | /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU |
| 4469 | object type, using the /proc file system. */ |
| 4470 | static LONGEST |
| 4471 | linux_proc_xfer_spu (struct target_ops *ops, enum target_object object, |
| 4472 | const char *annex, gdb_byte *readbuf, |
| 4473 | const gdb_byte *writebuf, |
| 4474 | ULONGEST offset, LONGEST len) |
| 4475 | { |
| 4476 | char buf[128]; |
| 4477 | int fd = 0; |
| 4478 | int ret = -1; |
| 4479 | int pid = PIDGET (inferior_ptid); |
| 4480 | |
| 4481 | if (!annex) |
| 4482 | { |
| 4483 | if (!readbuf) |
| 4484 | return -1; |
| 4485 | else |
| 4486 | return spu_enumerate_spu_ids (pid, readbuf, offset, len); |
| 4487 | } |
| 4488 | |
| 4489 | xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex); |
| 4490 | fd = open (buf, writebuf? O_WRONLY : O_RDONLY); |
| 4491 | if (fd <= 0) |
| 4492 | return -1; |
| 4493 | |
| 4494 | if (offset != 0 |
| 4495 | && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset) |
| 4496 | { |
| 4497 | close (fd); |
| 4498 | return 0; |
| 4499 | } |
| 4500 | |
| 4501 | if (writebuf) |
| 4502 | ret = write (fd, writebuf, (size_t) len); |
| 4503 | else if (readbuf) |
| 4504 | ret = read (fd, readbuf, (size_t) len); |
| 4505 | |
| 4506 | close (fd); |
| 4507 | return ret; |
| 4508 | } |
| 4509 | |
| 4510 | |
| 4511 | /* Parse LINE as a signal set and add its set bits to SIGS. */ |
| 4512 | |
| 4513 | static void |
| 4514 | add_line_to_sigset (const char *line, sigset_t *sigs) |
| 4515 | { |
| 4516 | int len = strlen (line) - 1; |
| 4517 | const char *p; |
| 4518 | int signum; |
| 4519 | |
| 4520 | if (line[len] != '\n') |
| 4521 | error (_("Could not parse signal set: %s"), line); |
| 4522 | |
| 4523 | p = line; |
| 4524 | signum = len * 4; |
| 4525 | while (len-- > 0) |
| 4526 | { |
| 4527 | int digit; |
| 4528 | |
| 4529 | if (*p >= '0' && *p <= '9') |
| 4530 | digit = *p - '0'; |
| 4531 | else if (*p >= 'a' && *p <= 'f') |
| 4532 | digit = *p - 'a' + 10; |
| 4533 | else |
| 4534 | error (_("Could not parse signal set: %s"), line); |
| 4535 | |
| 4536 | signum -= 4; |
| 4537 | |
| 4538 | if (digit & 1) |
| 4539 | sigaddset (sigs, signum + 1); |
| 4540 | if (digit & 2) |
| 4541 | sigaddset (sigs, signum + 2); |
| 4542 | if (digit & 4) |
| 4543 | sigaddset (sigs, signum + 3); |
| 4544 | if (digit & 8) |
| 4545 | sigaddset (sigs, signum + 4); |
| 4546 | |
| 4547 | p++; |
| 4548 | } |
| 4549 | } |
| 4550 | |
| 4551 | /* Find process PID's pending signals from /proc/pid/status and set |
| 4552 | SIGS to match. */ |
| 4553 | |
| 4554 | void |
| 4555 | linux_proc_pending_signals (int pid, sigset_t *pending, |
| 4556 | sigset_t *blocked, sigset_t *ignored) |
| 4557 | { |
| 4558 | FILE *procfile; |
| 4559 | char buffer[MAXPATHLEN], fname[MAXPATHLEN]; |
| 4560 | struct cleanup *cleanup; |
| 4561 | |
| 4562 | sigemptyset (pending); |
| 4563 | sigemptyset (blocked); |
| 4564 | sigemptyset (ignored); |
| 4565 | sprintf (fname, "/proc/%d/status", pid); |
| 4566 | procfile = fopen (fname, "r"); |
| 4567 | if (procfile == NULL) |
| 4568 | error (_("Could not open %s"), fname); |
| 4569 | cleanup = make_cleanup_fclose (procfile); |
| 4570 | |
| 4571 | while (fgets (buffer, MAXPATHLEN, procfile) != NULL) |
| 4572 | { |
| 4573 | /* Normal queued signals are on the SigPnd line in the status |
| 4574 | file. However, 2.6 kernels also have a "shared" pending |
| 4575 | queue for delivering signals to a thread group, so check for |
| 4576 | a ShdPnd line also. |
| 4577 | |
| 4578 | Unfortunately some Red Hat kernels include the shared pending |
| 4579 | queue but not the ShdPnd status field. */ |
| 4580 | |
| 4581 | if (strncmp (buffer, "SigPnd:\t", 8) == 0) |
| 4582 | add_line_to_sigset (buffer + 8, pending); |
| 4583 | else if (strncmp (buffer, "ShdPnd:\t", 8) == 0) |
| 4584 | add_line_to_sigset (buffer + 8, pending); |
| 4585 | else if (strncmp (buffer, "SigBlk:\t", 8) == 0) |
| 4586 | add_line_to_sigset (buffer + 8, blocked); |
| 4587 | else if (strncmp (buffer, "SigIgn:\t", 8) == 0) |
| 4588 | add_line_to_sigset (buffer + 8, ignored); |
| 4589 | } |
| 4590 | |
| 4591 | do_cleanups (cleanup); |
| 4592 | } |
| 4593 | |
| 4594 | static LONGEST |
| 4595 | linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object, |
| 4596 | const char *annex, gdb_byte *readbuf, |
| 4597 | const gdb_byte *writebuf, ULONGEST offset, LONGEST len) |
| 4598 | { |
| 4599 | gdb_assert (object == TARGET_OBJECT_OSDATA); |
| 4600 | |
| 4601 | return linux_common_xfer_osdata (annex, readbuf, offset, len); |
| 4602 | } |
| 4603 | |
| 4604 | static LONGEST |
| 4605 | linux_xfer_partial (struct target_ops *ops, enum target_object object, |
| 4606 | const char *annex, gdb_byte *readbuf, |
| 4607 | const gdb_byte *writebuf, ULONGEST offset, LONGEST len) |
| 4608 | { |
| 4609 | LONGEST xfer; |
| 4610 | |
| 4611 | if (object == TARGET_OBJECT_AUXV) |
| 4612 | return memory_xfer_auxv (ops, object, annex, readbuf, writebuf, |
| 4613 | offset, len); |
| 4614 | |
| 4615 | if (object == TARGET_OBJECT_OSDATA) |
| 4616 | return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf, |
| 4617 | offset, len); |
| 4618 | |
| 4619 | if (object == TARGET_OBJECT_SPU) |
| 4620 | return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf, |
| 4621 | offset, len); |
| 4622 | |
| 4623 | /* GDB calculates all the addresses in possibly larget width of the address. |
| 4624 | Address width needs to be masked before its final use - either by |
| 4625 | linux_proc_xfer_partial or inf_ptrace_xfer_partial. |
| 4626 | |
| 4627 | Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */ |
| 4628 | |
| 4629 | if (object == TARGET_OBJECT_MEMORY) |
| 4630 | { |
| 4631 | int addr_bit = gdbarch_addr_bit (target_gdbarch); |
| 4632 | |
| 4633 | if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT)) |
| 4634 | offset &= ((ULONGEST) 1 << addr_bit) - 1; |
| 4635 | } |
| 4636 | |
| 4637 | xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf, |
| 4638 | offset, len); |
| 4639 | if (xfer != 0) |
| 4640 | return xfer; |
| 4641 | |
| 4642 | return super_xfer_partial (ops, object, annex, readbuf, writebuf, |
| 4643 | offset, len); |
| 4644 | } |
| 4645 | |
| 4646 | static void |
| 4647 | cleanup_target_stop (void *arg) |
| 4648 | { |
| 4649 | ptid_t *ptid = (ptid_t *) arg; |
| 4650 | |
| 4651 | gdb_assert (arg != NULL); |
| 4652 | |
| 4653 | /* Unpause all */ |
| 4654 | target_resume (*ptid, 0, GDB_SIGNAL_0); |
| 4655 | } |
| 4656 | |
| 4657 | static VEC(static_tracepoint_marker_p) * |
| 4658 | linux_child_static_tracepoint_markers_by_strid (const char *strid) |
| 4659 | { |
| 4660 | char s[IPA_CMD_BUF_SIZE]; |
| 4661 | struct cleanup *old_chain; |
| 4662 | int pid = ptid_get_pid (inferior_ptid); |
| 4663 | VEC(static_tracepoint_marker_p) *markers = NULL; |
| 4664 | struct static_tracepoint_marker *marker = NULL; |
| 4665 | char *p = s; |
| 4666 | ptid_t ptid = ptid_build (pid, 0, 0); |
| 4667 | |
| 4668 | /* Pause all */ |
| 4669 | target_stop (ptid); |
| 4670 | |
| 4671 | memcpy (s, "qTfSTM", sizeof ("qTfSTM")); |
| 4672 | s[sizeof ("qTfSTM")] = 0; |
| 4673 | |
| 4674 | agent_run_command (pid, s, strlen (s) + 1); |
| 4675 | |
| 4676 | old_chain = make_cleanup (free_current_marker, &marker); |
| 4677 | make_cleanup (cleanup_target_stop, &ptid); |
| 4678 | |
| 4679 | while (*p++ == 'm') |
| 4680 | { |
| 4681 | if (marker == NULL) |
| 4682 | marker = XCNEW (struct static_tracepoint_marker); |
| 4683 | |
| 4684 | do |
| 4685 | { |
| 4686 | parse_static_tracepoint_marker_definition (p, &p, marker); |
| 4687 | |
| 4688 | if (strid == NULL || strcmp (strid, marker->str_id) == 0) |
| 4689 | { |
| 4690 | VEC_safe_push (static_tracepoint_marker_p, |
| 4691 | markers, marker); |
| 4692 | marker = NULL; |
| 4693 | } |
| 4694 | else |
| 4695 | { |
| 4696 | release_static_tracepoint_marker (marker); |
| 4697 | memset (marker, 0, sizeof (*marker)); |
| 4698 | } |
| 4699 | } |
| 4700 | while (*p++ == ','); /* comma-separated list */ |
| 4701 | |
| 4702 | memcpy (s, "qTsSTM", sizeof ("qTsSTM")); |
| 4703 | s[sizeof ("qTsSTM")] = 0; |
| 4704 | agent_run_command (pid, s, strlen (s) + 1); |
| 4705 | p = s; |
| 4706 | } |
| 4707 | |
| 4708 | do_cleanups (old_chain); |
| 4709 | |
| 4710 | return markers; |
| 4711 | } |
| 4712 | |
| 4713 | /* Create a prototype generic GNU/Linux target. The client can override |
| 4714 | it with local methods. */ |
| 4715 | |
| 4716 | static void |
| 4717 | linux_target_install_ops (struct target_ops *t) |
| 4718 | { |
| 4719 | t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint; |
| 4720 | t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint; |
| 4721 | t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint; |
| 4722 | t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint; |
| 4723 | t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint; |
| 4724 | t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint; |
| 4725 | t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint; |
| 4726 | t->to_pid_to_exec_file = linux_child_pid_to_exec_file; |
| 4727 | t->to_post_startup_inferior = linux_child_post_startup_inferior; |
| 4728 | t->to_post_attach = linux_child_post_attach; |
| 4729 | t->to_follow_fork = linux_child_follow_fork; |
| 4730 | t->to_make_corefile_notes = linux_nat_make_corefile_notes; |
| 4731 | |
| 4732 | super_xfer_partial = t->to_xfer_partial; |
| 4733 | t->to_xfer_partial = linux_xfer_partial; |
| 4734 | |
| 4735 | t->to_static_tracepoint_markers_by_strid |
| 4736 | = linux_child_static_tracepoint_markers_by_strid; |
| 4737 | } |
| 4738 | |
| 4739 | struct target_ops * |
| 4740 | linux_target (void) |
| 4741 | { |
| 4742 | struct target_ops *t; |
| 4743 | |
| 4744 | t = inf_ptrace_target (); |
| 4745 | linux_target_install_ops (t); |
| 4746 | |
| 4747 | return t; |
| 4748 | } |
| 4749 | |
| 4750 | struct target_ops * |
| 4751 | linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int)) |
| 4752 | { |
| 4753 | struct target_ops *t; |
| 4754 | |
| 4755 | t = inf_ptrace_trad_target (register_u_offset); |
| 4756 | linux_target_install_ops (t); |
| 4757 | |
| 4758 | return t; |
| 4759 | } |
| 4760 | |
| 4761 | /* target_is_async_p implementation. */ |
| 4762 | |
| 4763 | static int |
| 4764 | linux_nat_is_async_p (void) |
| 4765 | { |
| 4766 | /* NOTE: palves 2008-03-21: We're only async when the user requests |
| 4767 | it explicitly with the "set target-async" command. |
| 4768 | Someday, linux will always be async. */ |
| 4769 | return target_async_permitted; |
| 4770 | } |
| 4771 | |
| 4772 | /* target_can_async_p implementation. */ |
| 4773 | |
| 4774 | static int |
| 4775 | linux_nat_can_async_p (void) |
| 4776 | { |
| 4777 | /* NOTE: palves 2008-03-21: We're only async when the user requests |
| 4778 | it explicitly with the "set target-async" command. |
| 4779 | Someday, linux will always be async. */ |
| 4780 | return target_async_permitted; |
| 4781 | } |
| 4782 | |
| 4783 | static int |
| 4784 | linux_nat_supports_non_stop (void) |
| 4785 | { |
| 4786 | return 1; |
| 4787 | } |
| 4788 | |
| 4789 | /* True if we want to support multi-process. To be removed when GDB |
| 4790 | supports multi-exec. */ |
| 4791 | |
| 4792 | int linux_multi_process = 1; |
| 4793 | |
| 4794 | static int |
| 4795 | linux_nat_supports_multi_process (void) |
| 4796 | { |
| 4797 | return linux_multi_process; |
| 4798 | } |
| 4799 | |
| 4800 | static int |
| 4801 | linux_nat_supports_disable_randomization (void) |
| 4802 | { |
| 4803 | #ifdef HAVE_PERSONALITY |
| 4804 | return 1; |
| 4805 | #else |
| 4806 | return 0; |
| 4807 | #endif |
| 4808 | } |
| 4809 | |
| 4810 | static int async_terminal_is_ours = 1; |
| 4811 | |
| 4812 | /* target_terminal_inferior implementation. */ |
| 4813 | |
| 4814 | static void |
| 4815 | linux_nat_terminal_inferior (void) |
| 4816 | { |
| 4817 | if (!target_is_async_p ()) |
| 4818 | { |
| 4819 | /* Async mode is disabled. */ |
| 4820 | terminal_inferior (); |
| 4821 | return; |
| 4822 | } |
| 4823 | |
| 4824 | terminal_inferior (); |
| 4825 | |
| 4826 | /* Calls to target_terminal_*() are meant to be idempotent. */ |
| 4827 | if (!async_terminal_is_ours) |
| 4828 | return; |
| 4829 | |
| 4830 | delete_file_handler (input_fd); |
| 4831 | async_terminal_is_ours = 0; |
| 4832 | set_sigint_trap (); |
| 4833 | } |
| 4834 | |
| 4835 | /* target_terminal_ours implementation. */ |
| 4836 | |
| 4837 | static void |
| 4838 | linux_nat_terminal_ours (void) |
| 4839 | { |
| 4840 | if (!target_is_async_p ()) |
| 4841 | { |
| 4842 | /* Async mode is disabled. */ |
| 4843 | terminal_ours (); |
| 4844 | return; |
| 4845 | } |
| 4846 | |
| 4847 | /* GDB should never give the terminal to the inferior if the |
| 4848 | inferior is running in the background (run&, continue&, etc.), |
| 4849 | but claiming it sure should. */ |
| 4850 | terminal_ours (); |
| 4851 | |
| 4852 | if (async_terminal_is_ours) |
| 4853 | return; |
| 4854 | |
| 4855 | clear_sigint_trap (); |
| 4856 | add_file_handler (input_fd, stdin_event_handler, 0); |
| 4857 | async_terminal_is_ours = 1; |
| 4858 | } |
| 4859 | |
| 4860 | static void (*async_client_callback) (enum inferior_event_type event_type, |
| 4861 | void *context); |
| 4862 | static void *async_client_context; |
| 4863 | |
| 4864 | /* SIGCHLD handler that serves two purposes: In non-stop/async mode, |
| 4865 | so we notice when any child changes state, and notify the |
| 4866 | event-loop; it allows us to use sigsuspend in linux_nat_wait_1 |
| 4867 | above to wait for the arrival of a SIGCHLD. */ |
| 4868 | |
| 4869 | static void |
| 4870 | sigchld_handler (int signo) |
| 4871 | { |
| 4872 | int old_errno = errno; |
| 4873 | |
| 4874 | if (debug_linux_nat) |
| 4875 | ui_file_write_async_safe (gdb_stdlog, |
| 4876 | "sigchld\n", sizeof ("sigchld\n") - 1); |
| 4877 | |
| 4878 | if (signo == SIGCHLD |
| 4879 | && linux_nat_event_pipe[0] != -1) |
| 4880 | async_file_mark (); /* Let the event loop know that there are |
| 4881 | events to handle. */ |
| 4882 | |
| 4883 | errno = old_errno; |
| 4884 | } |
| 4885 | |
| 4886 | /* Callback registered with the target events file descriptor. */ |
| 4887 | |
| 4888 | static void |
| 4889 | handle_target_event (int error, gdb_client_data client_data) |
| 4890 | { |
| 4891 | (*async_client_callback) (INF_REG_EVENT, async_client_context); |
| 4892 | } |
| 4893 | |
| 4894 | /* Create/destroy the target events pipe. Returns previous state. */ |
| 4895 | |
| 4896 | static int |
| 4897 | linux_async_pipe (int enable) |
| 4898 | { |
| 4899 | int previous = (linux_nat_event_pipe[0] != -1); |
| 4900 | |
| 4901 | if (previous != enable) |
| 4902 | { |
| 4903 | sigset_t prev_mask; |
| 4904 | |
| 4905 | block_child_signals (&prev_mask); |
| 4906 | |
| 4907 | if (enable) |
| 4908 | { |
| 4909 | if (pipe (linux_nat_event_pipe) == -1) |
| 4910 | internal_error (__FILE__, __LINE__, |
| 4911 | "creating event pipe failed."); |
| 4912 | |
| 4913 | fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK); |
| 4914 | fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK); |
| 4915 | } |
| 4916 | else |
| 4917 | { |
| 4918 | close (linux_nat_event_pipe[0]); |
| 4919 | close (linux_nat_event_pipe[1]); |
| 4920 | linux_nat_event_pipe[0] = -1; |
| 4921 | linux_nat_event_pipe[1] = -1; |
| 4922 | } |
| 4923 | |
| 4924 | restore_child_signals_mask (&prev_mask); |
| 4925 | } |
| 4926 | |
| 4927 | return previous; |
| 4928 | } |
| 4929 | |
| 4930 | /* target_async implementation. */ |
| 4931 | |
| 4932 | static void |
| 4933 | linux_nat_async (void (*callback) (enum inferior_event_type event_type, |
| 4934 | void *context), void *context) |
| 4935 | { |
| 4936 | if (callback != NULL) |
| 4937 | { |
| 4938 | async_client_callback = callback; |
| 4939 | async_client_context = context; |
| 4940 | if (!linux_async_pipe (1)) |
| 4941 | { |
| 4942 | add_file_handler (linux_nat_event_pipe[0], |
| 4943 | handle_target_event, NULL); |
| 4944 | /* There may be pending events to handle. Tell the event loop |
| 4945 | to poll them. */ |
| 4946 | async_file_mark (); |
| 4947 | } |
| 4948 | } |
| 4949 | else |
| 4950 | { |
| 4951 | async_client_callback = callback; |
| 4952 | async_client_context = context; |
| 4953 | delete_file_handler (linux_nat_event_pipe[0]); |
| 4954 | linux_async_pipe (0); |
| 4955 | } |
| 4956 | return; |
| 4957 | } |
| 4958 | |
| 4959 | /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other |
| 4960 | event came out. */ |
| 4961 | |
| 4962 | static int |
| 4963 | linux_nat_stop_lwp (struct lwp_info *lwp, void *data) |
| 4964 | { |
| 4965 | if (!lwp->stopped) |
| 4966 | { |
| 4967 | ptid_t ptid = lwp->ptid; |
| 4968 | |
| 4969 | if (debug_linux_nat) |
| 4970 | fprintf_unfiltered (gdb_stdlog, |
| 4971 | "LNSL: running -> suspending %s\n", |
| 4972 | target_pid_to_str (lwp->ptid)); |
| 4973 | |
| 4974 | |
| 4975 | if (lwp->last_resume_kind == resume_stop) |
| 4976 | { |
| 4977 | if (debug_linux_nat) |
| 4978 | fprintf_unfiltered (gdb_stdlog, |
| 4979 | "linux-nat: already stopping LWP %ld at " |
| 4980 | "GDB's request\n", |
| 4981 | ptid_get_lwp (lwp->ptid)); |
| 4982 | return 0; |
| 4983 | } |
| 4984 | |
| 4985 | stop_callback (lwp, NULL); |
| 4986 | lwp->last_resume_kind = resume_stop; |
| 4987 | } |
| 4988 | else |
| 4989 | { |
| 4990 | /* Already known to be stopped; do nothing. */ |
| 4991 | |
| 4992 | if (debug_linux_nat) |
| 4993 | { |
| 4994 | if (find_thread_ptid (lwp->ptid)->stop_requested) |
| 4995 | fprintf_unfiltered (gdb_stdlog, |
| 4996 | "LNSL: already stopped/stop_requested %s\n", |
| 4997 | target_pid_to_str (lwp->ptid)); |
| 4998 | else |
| 4999 | fprintf_unfiltered (gdb_stdlog, |
| 5000 | "LNSL: already stopped/no " |
| 5001 | "stop_requested yet %s\n", |
| 5002 | target_pid_to_str (lwp->ptid)); |
| 5003 | } |
| 5004 | } |
| 5005 | return 0; |
| 5006 | } |
| 5007 | |
| 5008 | static void |
| 5009 | linux_nat_stop (ptid_t ptid) |
| 5010 | { |
| 5011 | if (non_stop) |
| 5012 | iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL); |
| 5013 | else |
| 5014 | linux_ops->to_stop (ptid); |
| 5015 | } |
| 5016 | |
| 5017 | static void |
| 5018 | linux_nat_close (int quitting) |
| 5019 | { |
| 5020 | /* Unregister from the event loop. */ |
| 5021 | if (linux_nat_is_async_p ()) |
| 5022 | linux_nat_async (NULL, 0); |
| 5023 | |
| 5024 | if (linux_ops->to_close) |
| 5025 | linux_ops->to_close (quitting); |
| 5026 | } |
| 5027 | |
| 5028 | /* When requests are passed down from the linux-nat layer to the |
| 5029 | single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are |
| 5030 | used. The address space pointer is stored in the inferior object, |
| 5031 | but the common code that is passed such ptid can't tell whether |
| 5032 | lwpid is a "main" process id or not (it assumes so). We reverse |
| 5033 | look up the "main" process id from the lwp here. */ |
| 5034 | |
| 5035 | static struct address_space * |
| 5036 | linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid) |
| 5037 | { |
| 5038 | struct lwp_info *lwp; |
| 5039 | struct inferior *inf; |
| 5040 | int pid; |
| 5041 | |
| 5042 | pid = GET_LWP (ptid); |
| 5043 | if (GET_LWP (ptid) == 0) |
| 5044 | { |
| 5045 | /* An (lwpid,0,0) ptid. Look up the lwp object to get at the |
| 5046 | tgid. */ |
| 5047 | lwp = find_lwp_pid (ptid); |
| 5048 | pid = GET_PID (lwp->ptid); |
| 5049 | } |
| 5050 | else |
| 5051 | { |
| 5052 | /* A (pid,lwpid,0) ptid. */ |
| 5053 | pid = GET_PID (ptid); |
| 5054 | } |
| 5055 | |
| 5056 | inf = find_inferior_pid (pid); |
| 5057 | gdb_assert (inf != NULL); |
| 5058 | return inf->aspace; |
| 5059 | } |
| 5060 | |
| 5061 | /* Return the cached value of the processor core for thread PTID. */ |
| 5062 | |
| 5063 | static int |
| 5064 | linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid) |
| 5065 | { |
| 5066 | struct lwp_info *info = find_lwp_pid (ptid); |
| 5067 | |
| 5068 | if (info) |
| 5069 | return info->core; |
| 5070 | return -1; |
| 5071 | } |
| 5072 | |
| 5073 | void |
| 5074 | linux_nat_add_target (struct target_ops *t) |
| 5075 | { |
| 5076 | /* Save the provided single-threaded target. We save this in a separate |
| 5077 | variable because another target we've inherited from (e.g. inf-ptrace) |
| 5078 | may have saved a pointer to T; we want to use it for the final |
| 5079 | process stratum target. */ |
| 5080 | linux_ops_saved = *t; |
| 5081 | linux_ops = &linux_ops_saved; |
| 5082 | |
| 5083 | /* Override some methods for multithreading. */ |
| 5084 | t->to_create_inferior = linux_nat_create_inferior; |
| 5085 | t->to_attach = linux_nat_attach; |
| 5086 | t->to_detach = linux_nat_detach; |
| 5087 | t->to_resume = linux_nat_resume; |
| 5088 | t->to_wait = linux_nat_wait; |
| 5089 | t->to_pass_signals = linux_nat_pass_signals; |
| 5090 | t->to_xfer_partial = linux_nat_xfer_partial; |
| 5091 | t->to_kill = linux_nat_kill; |
| 5092 | t->to_mourn_inferior = linux_nat_mourn_inferior; |
| 5093 | t->to_thread_alive = linux_nat_thread_alive; |
| 5094 | t->to_pid_to_str = linux_nat_pid_to_str; |
| 5095 | t->to_thread_name = linux_nat_thread_name; |
| 5096 | t->to_has_thread_control = tc_schedlock; |
| 5097 | t->to_thread_address_space = linux_nat_thread_address_space; |
| 5098 | t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint; |
| 5099 | t->to_stopped_data_address = linux_nat_stopped_data_address; |
| 5100 | |
| 5101 | t->to_can_async_p = linux_nat_can_async_p; |
| 5102 | t->to_is_async_p = linux_nat_is_async_p; |
| 5103 | t->to_supports_non_stop = linux_nat_supports_non_stop; |
| 5104 | t->to_async = linux_nat_async; |
| 5105 | t->to_terminal_inferior = linux_nat_terminal_inferior; |
| 5106 | t->to_terminal_ours = linux_nat_terminal_ours; |
| 5107 | t->to_close = linux_nat_close; |
| 5108 | |
| 5109 | /* Methods for non-stop support. */ |
| 5110 | t->to_stop = linux_nat_stop; |
| 5111 | |
| 5112 | t->to_supports_multi_process = linux_nat_supports_multi_process; |
| 5113 | |
| 5114 | t->to_supports_disable_randomization |
| 5115 | = linux_nat_supports_disable_randomization; |
| 5116 | |
| 5117 | t->to_core_of_thread = linux_nat_core_of_thread; |
| 5118 | |
| 5119 | /* We don't change the stratum; this target will sit at |
| 5120 | process_stratum and thread_db will set at thread_stratum. This |
| 5121 | is a little strange, since this is a multi-threaded-capable |
| 5122 | target, but we want to be on the stack below thread_db, and we |
| 5123 | also want to be used for single-threaded processes. */ |
| 5124 | |
| 5125 | add_target (t); |
| 5126 | } |
| 5127 | |
| 5128 | /* Register a method to call whenever a new thread is attached. */ |
| 5129 | void |
| 5130 | linux_nat_set_new_thread (struct target_ops *t, |
| 5131 | void (*new_thread) (struct lwp_info *)) |
| 5132 | { |
| 5133 | /* Save the pointer. We only support a single registered instance |
| 5134 | of the GNU/Linux native target, so we do not need to map this to |
| 5135 | T. */ |
| 5136 | linux_nat_new_thread = new_thread; |
| 5137 | } |
| 5138 | |
| 5139 | /* Register a method that converts a siginfo object between the layout |
| 5140 | that ptrace returns, and the layout in the architecture of the |
| 5141 | inferior. */ |
| 5142 | void |
| 5143 | linux_nat_set_siginfo_fixup (struct target_ops *t, |
| 5144 | int (*siginfo_fixup) (siginfo_t *, |
| 5145 | gdb_byte *, |
| 5146 | int)) |
| 5147 | { |
| 5148 | /* Save the pointer. */ |
| 5149 | linux_nat_siginfo_fixup = siginfo_fixup; |
| 5150 | } |
| 5151 | |
| 5152 | /* Register a method to call prior to resuming a thread. */ |
| 5153 | |
| 5154 | void |
| 5155 | linux_nat_set_prepare_to_resume (struct target_ops *t, |
| 5156 | void (*prepare_to_resume) (struct lwp_info *)) |
| 5157 | { |
| 5158 | /* Save the pointer. */ |
| 5159 | linux_nat_prepare_to_resume = prepare_to_resume; |
| 5160 | } |
| 5161 | |
| 5162 | /* See linux-nat.h. */ |
| 5163 | |
| 5164 | int |
| 5165 | linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo) |
| 5166 | { |
| 5167 | int pid; |
| 5168 | |
| 5169 | pid = GET_LWP (ptid); |
| 5170 | if (pid == 0) |
| 5171 | pid = GET_PID (ptid); |
| 5172 | |
| 5173 | errno = 0; |
| 5174 | ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo); |
| 5175 | if (errno != 0) |
| 5176 | { |
| 5177 | memset (siginfo, 0, sizeof (*siginfo)); |
| 5178 | return 0; |
| 5179 | } |
| 5180 | return 1; |
| 5181 | } |
| 5182 | |
| 5183 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 5184 | extern initialize_file_ftype _initialize_linux_nat; |
| 5185 | |
| 5186 | void |
| 5187 | _initialize_linux_nat (void) |
| 5188 | { |
| 5189 | add_setshow_zinteger_cmd ("lin-lwp", class_maintenance, |
| 5190 | &debug_linux_nat, _("\ |
| 5191 | Set debugging of GNU/Linux lwp module."), _("\ |
| 5192 | Show debugging of GNU/Linux lwp module."), _("\ |
| 5193 | Enables printf debugging output."), |
| 5194 | NULL, |
| 5195 | show_debug_linux_nat, |
| 5196 | &setdebuglist, &showdebuglist); |
| 5197 | |
| 5198 | /* Save this mask as the default. */ |
| 5199 | sigprocmask (SIG_SETMASK, NULL, &normal_mask); |
| 5200 | |
| 5201 | /* Install a SIGCHLD handler. */ |
| 5202 | sigchld_action.sa_handler = sigchld_handler; |
| 5203 | sigemptyset (&sigchld_action.sa_mask); |
| 5204 | sigchld_action.sa_flags = SA_RESTART; |
| 5205 | |
| 5206 | /* Make it the default. */ |
| 5207 | sigaction (SIGCHLD, &sigchld_action, NULL); |
| 5208 | |
| 5209 | /* Make sure we don't block SIGCHLD during a sigsuspend. */ |
| 5210 | sigprocmask (SIG_SETMASK, NULL, &suspend_mask); |
| 5211 | sigdelset (&suspend_mask, SIGCHLD); |
| 5212 | |
| 5213 | sigemptyset (&blocked_mask); |
| 5214 | } |
| 5215 | \f |
| 5216 | |
| 5217 | /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to |
| 5218 | the GNU/Linux Threads library and therefore doesn't really belong |
| 5219 | here. */ |
| 5220 | |
| 5221 | /* Read variable NAME in the target and return its value if found. |
| 5222 | Otherwise return zero. It is assumed that the type of the variable |
| 5223 | is `int'. */ |
| 5224 | |
| 5225 | static int |
| 5226 | get_signo (const char *name) |
| 5227 | { |
| 5228 | struct minimal_symbol *ms; |
| 5229 | int signo; |
| 5230 | |
| 5231 | ms = lookup_minimal_symbol (name, NULL, NULL); |
| 5232 | if (ms == NULL) |
| 5233 | return 0; |
| 5234 | |
| 5235 | if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo, |
| 5236 | sizeof (signo)) != 0) |
| 5237 | return 0; |
| 5238 | |
| 5239 | return signo; |
| 5240 | } |
| 5241 | |
| 5242 | /* Return the set of signals used by the threads library in *SET. */ |
| 5243 | |
| 5244 | void |
| 5245 | lin_thread_get_thread_signals (sigset_t *set) |
| 5246 | { |
| 5247 | struct sigaction action; |
| 5248 | int restart, cancel; |
| 5249 | |
| 5250 | sigemptyset (&blocked_mask); |
| 5251 | sigemptyset (set); |
| 5252 | |
| 5253 | restart = get_signo ("__pthread_sig_restart"); |
| 5254 | cancel = get_signo ("__pthread_sig_cancel"); |
| 5255 | |
| 5256 | /* LinuxThreads normally uses the first two RT signals, but in some legacy |
| 5257 | cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does |
| 5258 | not provide any way for the debugger to query the signal numbers - |
| 5259 | fortunately they don't change! */ |
| 5260 | |
| 5261 | if (restart == 0) |
| 5262 | restart = __SIGRTMIN; |
| 5263 | |
| 5264 | if (cancel == 0) |
| 5265 | cancel = __SIGRTMIN + 1; |
| 5266 | |
| 5267 | sigaddset (set, restart); |
| 5268 | sigaddset (set, cancel); |
| 5269 | |
| 5270 | /* The GNU/Linux Threads library makes terminating threads send a |
| 5271 | special "cancel" signal instead of SIGCHLD. Make sure we catch |
| 5272 | those (to prevent them from terminating GDB itself, which is |
| 5273 | likely to be their default action) and treat them the same way as |
| 5274 | SIGCHLD. */ |
| 5275 | |
| 5276 | action.sa_handler = sigchld_handler; |
| 5277 | sigemptyset (&action.sa_mask); |
| 5278 | action.sa_flags = SA_RESTART; |
| 5279 | sigaction (cancel, &action, NULL); |
| 5280 | |
| 5281 | /* We block the "cancel" signal throughout this code ... */ |
| 5282 | sigaddset (&blocked_mask, cancel); |
| 5283 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); |
| 5284 | |
| 5285 | /* ... except during a sigsuspend. */ |
| 5286 | sigdelset (&suspend_mask, cancel); |
| 5287 | } |