| 1 | /* Low level interface to ptrace, for the remote server for GDB. |
| 2 | Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, |
| 3 | 2006, 2007, 2008 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 "server.h" |
| 21 | #include "linux-low.h" |
| 22 | |
| 23 | #include <sys/wait.h> |
| 24 | #include <stdio.h> |
| 25 | #include <sys/param.h> |
| 26 | #include <sys/dir.h> |
| 27 | #include <sys/ptrace.h> |
| 28 | #include <sys/user.h> |
| 29 | #include <signal.h> |
| 30 | #include <sys/ioctl.h> |
| 31 | #include <fcntl.h> |
| 32 | #include <string.h> |
| 33 | #include <stdlib.h> |
| 34 | #include <unistd.h> |
| 35 | #include <errno.h> |
| 36 | #include <sys/syscall.h> |
| 37 | #include <sched.h> |
| 38 | |
| 39 | #ifndef PTRACE_GETSIGINFO |
| 40 | # define PTRACE_GETSIGINFO 0x4202 |
| 41 | # define PTRACE_SETSIGINFO 0x4203 |
| 42 | #endif |
| 43 | |
| 44 | #ifndef O_LARGEFILE |
| 45 | #define O_LARGEFILE 0 |
| 46 | #endif |
| 47 | |
| 48 | /* If the system headers did not provide the constants, hard-code the normal |
| 49 | values. */ |
| 50 | #ifndef PTRACE_EVENT_FORK |
| 51 | |
| 52 | #define PTRACE_SETOPTIONS 0x4200 |
| 53 | #define PTRACE_GETEVENTMSG 0x4201 |
| 54 | |
| 55 | /* options set using PTRACE_SETOPTIONS */ |
| 56 | #define PTRACE_O_TRACESYSGOOD 0x00000001 |
| 57 | #define PTRACE_O_TRACEFORK 0x00000002 |
| 58 | #define PTRACE_O_TRACEVFORK 0x00000004 |
| 59 | #define PTRACE_O_TRACECLONE 0x00000008 |
| 60 | #define PTRACE_O_TRACEEXEC 0x00000010 |
| 61 | #define PTRACE_O_TRACEVFORKDONE 0x00000020 |
| 62 | #define PTRACE_O_TRACEEXIT 0x00000040 |
| 63 | |
| 64 | /* Wait extended result codes for the above trace options. */ |
| 65 | #define PTRACE_EVENT_FORK 1 |
| 66 | #define PTRACE_EVENT_VFORK 2 |
| 67 | #define PTRACE_EVENT_CLONE 3 |
| 68 | #define PTRACE_EVENT_EXEC 4 |
| 69 | #define PTRACE_EVENT_VFORK_DONE 5 |
| 70 | #define PTRACE_EVENT_EXIT 6 |
| 71 | |
| 72 | #endif /* PTRACE_EVENT_FORK */ |
| 73 | |
| 74 | /* We can't always assume that this flag is available, but all systems |
| 75 | with the ptrace event handlers also have __WALL, so it's safe to use |
| 76 | in some contexts. */ |
| 77 | #ifndef __WALL |
| 78 | #define __WALL 0x40000000 /* Wait for any child. */ |
| 79 | #endif |
| 80 | |
| 81 | #ifdef __UCLIBC__ |
| 82 | #if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__)) |
| 83 | #define HAS_NOMMU |
| 84 | #endif |
| 85 | #endif |
| 86 | |
| 87 | /* ``all_threads'' is keyed by the LWP ID, which we use as the GDB protocol |
| 88 | representation of the thread ID. |
| 89 | |
| 90 | ``all_processes'' is keyed by the process ID - which on Linux is (presently) |
| 91 | the same as the LWP ID. */ |
| 92 | |
| 93 | struct inferior_list all_processes; |
| 94 | |
| 95 | /* A list of all unknown processes which receive stop signals. Some other |
| 96 | process will presumably claim each of these as forked children |
| 97 | momentarily. */ |
| 98 | |
| 99 | struct inferior_list stopped_pids; |
| 100 | |
| 101 | /* FIXME this is a bit of a hack, and could be removed. */ |
| 102 | int stopping_threads; |
| 103 | |
| 104 | /* FIXME make into a target method? */ |
| 105 | int using_threads = 1; |
| 106 | static int thread_db_active; |
| 107 | |
| 108 | static int must_set_ptrace_flags; |
| 109 | |
| 110 | static void linux_resume_one_process (struct inferior_list_entry *entry, |
| 111 | int step, int signal, siginfo_t *info); |
| 112 | static void linux_resume (struct thread_resume *resume_info); |
| 113 | static void stop_all_processes (void); |
| 114 | static int linux_wait_for_event (struct thread_info *child); |
| 115 | static int check_removed_breakpoint (struct process_info *event_child); |
| 116 | static void *add_process (unsigned long pid); |
| 117 | |
| 118 | struct pending_signals |
| 119 | { |
| 120 | int signal; |
| 121 | siginfo_t info; |
| 122 | struct pending_signals *prev; |
| 123 | }; |
| 124 | |
| 125 | #define PTRACE_ARG3_TYPE long |
| 126 | #define PTRACE_XFER_TYPE long |
| 127 | |
| 128 | #ifdef HAVE_LINUX_REGSETS |
| 129 | static int use_regsets_p = 1; |
| 130 | #endif |
| 131 | |
| 132 | #define pid_of(proc) ((proc)->head.id) |
| 133 | |
| 134 | /* FIXME: Delete eventually. */ |
| 135 | #define inferior_pid (pid_of (get_thread_process (current_inferior))) |
| 136 | |
| 137 | static void |
| 138 | handle_extended_wait (struct process_info *event_child, int wstat) |
| 139 | { |
| 140 | int event = wstat >> 16; |
| 141 | struct process_info *new_process; |
| 142 | |
| 143 | if (event == PTRACE_EVENT_CLONE) |
| 144 | { |
| 145 | unsigned long new_pid; |
| 146 | int ret, status; |
| 147 | |
| 148 | ptrace (PTRACE_GETEVENTMSG, inferior_pid, 0, &new_pid); |
| 149 | |
| 150 | /* If we haven't already seen the new PID stop, wait for it now. */ |
| 151 | if (! pull_pid_from_list (&stopped_pids, new_pid)) |
| 152 | { |
| 153 | /* The new child has a pending SIGSTOP. We can't affect it until it |
| 154 | hits the SIGSTOP, but we're already attached. */ |
| 155 | |
| 156 | do { |
| 157 | ret = waitpid (new_pid, &status, __WALL); |
| 158 | } while (ret == -1 && errno == EINTR); |
| 159 | |
| 160 | if (ret == -1) |
| 161 | perror_with_name ("waiting for new child"); |
| 162 | else if (ret != new_pid) |
| 163 | warning ("wait returned unexpected PID %d", ret); |
| 164 | else if (!WIFSTOPPED (status)) |
| 165 | warning ("wait returned unexpected status 0x%x", status); |
| 166 | } |
| 167 | |
| 168 | ptrace (PTRACE_SETOPTIONS, new_pid, 0, PTRACE_O_TRACECLONE); |
| 169 | |
| 170 | new_process = (struct process_info *) add_process (new_pid); |
| 171 | add_thread (new_pid, new_process, new_pid); |
| 172 | new_thread_notify (thread_id_to_gdb_id (new_process->lwpid)); |
| 173 | |
| 174 | /* Normally we will get the pending SIGSTOP. But in some cases |
| 175 | we might get another signal delivered to the group first. |
| 176 | If we do, be sure not to lose it. */ |
| 177 | if (WSTOPSIG (status) == SIGSTOP) |
| 178 | { |
| 179 | if (stopping_threads) |
| 180 | new_process->stopped = 1; |
| 181 | else |
| 182 | ptrace (PTRACE_CONT, new_pid, 0, 0); |
| 183 | } |
| 184 | else |
| 185 | { |
| 186 | new_process->stop_expected = 1; |
| 187 | if (stopping_threads) |
| 188 | { |
| 189 | new_process->stopped = 1; |
| 190 | new_process->status_pending_p = 1; |
| 191 | new_process->status_pending = status; |
| 192 | } |
| 193 | else |
| 194 | /* Pass the signal on. This is what GDB does - except |
| 195 | shouldn't we really report it instead? */ |
| 196 | ptrace (PTRACE_CONT, new_pid, 0, WSTOPSIG (status)); |
| 197 | } |
| 198 | |
| 199 | /* Always resume the current thread. If we are stopping |
| 200 | threads, it will have a pending SIGSTOP; we may as well |
| 201 | collect it now. */ |
| 202 | linux_resume_one_process (&event_child->head, |
| 203 | event_child->stepping, 0, NULL); |
| 204 | } |
| 205 | } |
| 206 | |
| 207 | /* This function should only be called if the process got a SIGTRAP. |
| 208 | The SIGTRAP could mean several things. |
| 209 | |
| 210 | On i386, where decr_pc_after_break is non-zero: |
| 211 | If we were single-stepping this process using PTRACE_SINGLESTEP, |
| 212 | we will get only the one SIGTRAP (even if the instruction we |
| 213 | stepped over was a breakpoint). The value of $eip will be the |
| 214 | next instruction. |
| 215 | If we continue the process using PTRACE_CONT, we will get a |
| 216 | SIGTRAP when we hit a breakpoint. The value of $eip will be |
| 217 | the instruction after the breakpoint (i.e. needs to be |
| 218 | decremented). If we report the SIGTRAP to GDB, we must also |
| 219 | report the undecremented PC. If we cancel the SIGTRAP, we |
| 220 | must resume at the decremented PC. |
| 221 | |
| 222 | (Presumably, not yet tested) On a non-decr_pc_after_break machine |
| 223 | with hardware or kernel single-step: |
| 224 | If we single-step over a breakpoint instruction, our PC will |
| 225 | point at the following instruction. If we continue and hit a |
| 226 | breakpoint instruction, our PC will point at the breakpoint |
| 227 | instruction. */ |
| 228 | |
| 229 | static CORE_ADDR |
| 230 | get_stop_pc (void) |
| 231 | { |
| 232 | CORE_ADDR stop_pc = (*the_low_target.get_pc) (); |
| 233 | |
| 234 | if (get_thread_process (current_inferior)->stepping) |
| 235 | return stop_pc; |
| 236 | else |
| 237 | return stop_pc - the_low_target.decr_pc_after_break; |
| 238 | } |
| 239 | |
| 240 | static void * |
| 241 | add_process (unsigned long pid) |
| 242 | { |
| 243 | struct process_info *process; |
| 244 | |
| 245 | process = (struct process_info *) malloc (sizeof (*process)); |
| 246 | memset (process, 0, sizeof (*process)); |
| 247 | |
| 248 | process->head.id = pid; |
| 249 | process->lwpid = pid; |
| 250 | |
| 251 | add_inferior_to_list (&all_processes, &process->head); |
| 252 | |
| 253 | return process; |
| 254 | } |
| 255 | |
| 256 | /* Start an inferior process and returns its pid. |
| 257 | ALLARGS is a vector of program-name and args. */ |
| 258 | |
| 259 | static int |
| 260 | linux_create_inferior (char *program, char **allargs) |
| 261 | { |
| 262 | void *new_process; |
| 263 | int pid; |
| 264 | |
| 265 | #if defined(__UCLIBC__) && defined(HAS_NOMMU) |
| 266 | pid = vfork (); |
| 267 | #else |
| 268 | pid = fork (); |
| 269 | #endif |
| 270 | if (pid < 0) |
| 271 | perror_with_name ("fork"); |
| 272 | |
| 273 | if (pid == 0) |
| 274 | { |
| 275 | ptrace (PTRACE_TRACEME, 0, 0, 0); |
| 276 | |
| 277 | signal (__SIGRTMIN + 1, SIG_DFL); |
| 278 | |
| 279 | setpgid (0, 0); |
| 280 | |
| 281 | execv (program, allargs); |
| 282 | if (errno == ENOENT) |
| 283 | execvp (program, allargs); |
| 284 | |
| 285 | fprintf (stderr, "Cannot exec %s: %s.\n", program, |
| 286 | strerror (errno)); |
| 287 | fflush (stderr); |
| 288 | _exit (0177); |
| 289 | } |
| 290 | |
| 291 | new_process = add_process (pid); |
| 292 | add_thread (pid, new_process, pid); |
| 293 | must_set_ptrace_flags = 1; |
| 294 | |
| 295 | return pid; |
| 296 | } |
| 297 | |
| 298 | /* Attach to an inferior process. */ |
| 299 | |
| 300 | void |
| 301 | linux_attach_lwp (unsigned long pid) |
| 302 | { |
| 303 | struct process_info *new_process; |
| 304 | |
| 305 | if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0) |
| 306 | { |
| 307 | if (all_threads.head != NULL) |
| 308 | { |
| 309 | /* If we fail to attach to an LWP, just warn. */ |
| 310 | fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid, |
| 311 | strerror (errno), errno); |
| 312 | fflush (stderr); |
| 313 | return; |
| 314 | } |
| 315 | else |
| 316 | /* If we fail to attach to a process, report an error. */ |
| 317 | error ("Cannot attach to process %ld: %s (%d)\n", pid, |
| 318 | strerror (errno), errno); |
| 319 | } |
| 320 | |
| 321 | ptrace (PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACECLONE); |
| 322 | |
| 323 | new_process = (struct process_info *) add_process (pid); |
| 324 | add_thread (pid, new_process, pid); |
| 325 | new_thread_notify (thread_id_to_gdb_id (new_process->lwpid)); |
| 326 | |
| 327 | /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH |
| 328 | brings it to a halt. We should ignore that SIGSTOP and resume the process |
| 329 | (unless this is the first process, in which case the flag will be cleared |
| 330 | in linux_attach). |
| 331 | |
| 332 | On the other hand, if we are currently trying to stop all threads, we |
| 333 | should treat the new thread as if we had sent it a SIGSTOP. This works |
| 334 | because we are guaranteed that add_process added us to the end of the |
| 335 | list, and so the new thread has not yet reached wait_for_sigstop (but |
| 336 | will). */ |
| 337 | if (! stopping_threads) |
| 338 | new_process->stop_expected = 1; |
| 339 | } |
| 340 | |
| 341 | int |
| 342 | linux_attach (unsigned long pid) |
| 343 | { |
| 344 | struct process_info *process; |
| 345 | |
| 346 | linux_attach_lwp (pid); |
| 347 | |
| 348 | /* Don't ignore the initial SIGSTOP if we just attached to this process. |
| 349 | It will be collected by wait shortly. */ |
| 350 | process = (struct process_info *) find_inferior_id (&all_processes, pid); |
| 351 | process->stop_expected = 0; |
| 352 | |
| 353 | return 0; |
| 354 | } |
| 355 | |
| 356 | /* Kill the inferior process. Make us have no inferior. */ |
| 357 | |
| 358 | static void |
| 359 | linux_kill_one_process (struct inferior_list_entry *entry) |
| 360 | { |
| 361 | struct thread_info *thread = (struct thread_info *) entry; |
| 362 | struct process_info *process = get_thread_process (thread); |
| 363 | int wstat; |
| 364 | |
| 365 | /* We avoid killing the first thread here, because of a Linux kernel (at |
| 366 | least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before |
| 367 | the children get a chance to be reaped, it will remain a zombie |
| 368 | forever. */ |
| 369 | if (entry == all_threads.head) |
| 370 | return; |
| 371 | |
| 372 | do |
| 373 | { |
| 374 | ptrace (PTRACE_KILL, pid_of (process), 0, 0); |
| 375 | |
| 376 | /* Make sure it died. The loop is most likely unnecessary. */ |
| 377 | wstat = linux_wait_for_event (thread); |
| 378 | } while (WIFSTOPPED (wstat)); |
| 379 | } |
| 380 | |
| 381 | static void |
| 382 | linux_kill (void) |
| 383 | { |
| 384 | struct thread_info *thread = (struct thread_info *) all_threads.head; |
| 385 | struct process_info *process; |
| 386 | int wstat; |
| 387 | |
| 388 | if (thread == NULL) |
| 389 | return; |
| 390 | |
| 391 | for_each_inferior (&all_threads, linux_kill_one_process); |
| 392 | |
| 393 | /* See the comment in linux_kill_one_process. We did not kill the first |
| 394 | thread in the list, so do so now. */ |
| 395 | process = get_thread_process (thread); |
| 396 | do |
| 397 | { |
| 398 | ptrace (PTRACE_KILL, pid_of (process), 0, 0); |
| 399 | |
| 400 | /* Make sure it died. The loop is most likely unnecessary. */ |
| 401 | wstat = linux_wait_for_event (thread); |
| 402 | } while (WIFSTOPPED (wstat)); |
| 403 | |
| 404 | clear_inferiors (); |
| 405 | free (all_processes.head); |
| 406 | all_processes.head = all_processes.tail = NULL; |
| 407 | } |
| 408 | |
| 409 | static void |
| 410 | linux_detach_one_process (struct inferior_list_entry *entry) |
| 411 | { |
| 412 | struct thread_info *thread = (struct thread_info *) entry; |
| 413 | struct process_info *process = get_thread_process (thread); |
| 414 | |
| 415 | /* Make sure the process isn't stopped at a breakpoint that's |
| 416 | no longer there. */ |
| 417 | check_removed_breakpoint (process); |
| 418 | |
| 419 | /* If this process is stopped but is expecting a SIGSTOP, then make |
| 420 | sure we take care of that now. This isn't absolutely guaranteed |
| 421 | to collect the SIGSTOP, but is fairly likely to. */ |
| 422 | if (process->stop_expected) |
| 423 | { |
| 424 | /* Clear stop_expected, so that the SIGSTOP will be reported. */ |
| 425 | process->stop_expected = 0; |
| 426 | if (process->stopped) |
| 427 | linux_resume_one_process (&process->head, 0, 0, NULL); |
| 428 | linux_wait_for_event (thread); |
| 429 | } |
| 430 | |
| 431 | /* Flush any pending changes to the process's registers. */ |
| 432 | regcache_invalidate_one ((struct inferior_list_entry *) |
| 433 | get_process_thread (process)); |
| 434 | |
| 435 | /* Finally, let it resume. */ |
| 436 | ptrace (PTRACE_DETACH, pid_of (process), 0, 0); |
| 437 | } |
| 438 | |
| 439 | static int |
| 440 | linux_detach (void) |
| 441 | { |
| 442 | delete_all_breakpoints (); |
| 443 | for_each_inferior (&all_threads, linux_detach_one_process); |
| 444 | clear_inferiors (); |
| 445 | free (all_processes.head); |
| 446 | all_processes.head = all_processes.tail = NULL; |
| 447 | return 0; |
| 448 | } |
| 449 | |
| 450 | static void |
| 451 | linux_join (void) |
| 452 | { |
| 453 | extern unsigned long signal_pid; |
| 454 | int status, ret; |
| 455 | |
| 456 | do { |
| 457 | ret = waitpid (signal_pid, &status, 0); |
| 458 | if (WIFEXITED (status) || WIFSIGNALED (status)) |
| 459 | break; |
| 460 | } while (ret != -1 || errno != ECHILD); |
| 461 | } |
| 462 | |
| 463 | /* Return nonzero if the given thread is still alive. */ |
| 464 | static int |
| 465 | linux_thread_alive (unsigned long lwpid) |
| 466 | { |
| 467 | if (find_inferior_id (&all_threads, lwpid) != NULL) |
| 468 | return 1; |
| 469 | else |
| 470 | return 0; |
| 471 | } |
| 472 | |
| 473 | /* Return nonzero if this process stopped at a breakpoint which |
| 474 | no longer appears to be inserted. Also adjust the PC |
| 475 | appropriately to resume where the breakpoint used to be. */ |
| 476 | static int |
| 477 | check_removed_breakpoint (struct process_info *event_child) |
| 478 | { |
| 479 | CORE_ADDR stop_pc; |
| 480 | struct thread_info *saved_inferior; |
| 481 | |
| 482 | if (event_child->pending_is_breakpoint == 0) |
| 483 | return 0; |
| 484 | |
| 485 | if (debug_threads) |
| 486 | fprintf (stderr, "Checking for breakpoint in process %ld.\n", |
| 487 | event_child->lwpid); |
| 488 | |
| 489 | saved_inferior = current_inferior; |
| 490 | current_inferior = get_process_thread (event_child); |
| 491 | |
| 492 | stop_pc = get_stop_pc (); |
| 493 | |
| 494 | /* If the PC has changed since we stopped, then we shouldn't do |
| 495 | anything. This happens if, for instance, GDB handled the |
| 496 | decr_pc_after_break subtraction itself. */ |
| 497 | if (stop_pc != event_child->pending_stop_pc) |
| 498 | { |
| 499 | if (debug_threads) |
| 500 | fprintf (stderr, "Ignoring, PC was changed. Old PC was 0x%08llx\n", |
| 501 | event_child->pending_stop_pc); |
| 502 | |
| 503 | event_child->pending_is_breakpoint = 0; |
| 504 | current_inferior = saved_inferior; |
| 505 | return 0; |
| 506 | } |
| 507 | |
| 508 | /* If the breakpoint is still there, we will report hitting it. */ |
| 509 | if ((*the_low_target.breakpoint_at) (stop_pc)) |
| 510 | { |
| 511 | if (debug_threads) |
| 512 | fprintf (stderr, "Ignoring, breakpoint is still present.\n"); |
| 513 | current_inferior = saved_inferior; |
| 514 | return 0; |
| 515 | } |
| 516 | |
| 517 | if (debug_threads) |
| 518 | fprintf (stderr, "Removed breakpoint.\n"); |
| 519 | |
| 520 | /* For decr_pc_after_break targets, here is where we perform the |
| 521 | decrement. We go immediately from this function to resuming, |
| 522 | and can not safely call get_stop_pc () again. */ |
| 523 | if (the_low_target.set_pc != NULL) |
| 524 | (*the_low_target.set_pc) (stop_pc); |
| 525 | |
| 526 | /* We consumed the pending SIGTRAP. */ |
| 527 | event_child->pending_is_breakpoint = 0; |
| 528 | event_child->status_pending_p = 0; |
| 529 | event_child->status_pending = 0; |
| 530 | |
| 531 | current_inferior = saved_inferior; |
| 532 | return 1; |
| 533 | } |
| 534 | |
| 535 | /* Return 1 if this process has an interesting status pending. This function |
| 536 | may silently resume an inferior process. */ |
| 537 | static int |
| 538 | status_pending_p (struct inferior_list_entry *entry, void *dummy) |
| 539 | { |
| 540 | struct process_info *process = (struct process_info *) entry; |
| 541 | |
| 542 | if (process->status_pending_p) |
| 543 | if (check_removed_breakpoint (process)) |
| 544 | { |
| 545 | /* This thread was stopped at a breakpoint, and the breakpoint |
| 546 | is now gone. We were told to continue (or step...) all threads, |
| 547 | so GDB isn't trying to single-step past this breakpoint. |
| 548 | So instead of reporting the old SIGTRAP, pretend we got to |
| 549 | the breakpoint just after it was removed instead of just |
| 550 | before; resume the process. */ |
| 551 | linux_resume_one_process (&process->head, 0, 0, NULL); |
| 552 | return 0; |
| 553 | } |
| 554 | |
| 555 | return process->status_pending_p; |
| 556 | } |
| 557 | |
| 558 | static void |
| 559 | linux_wait_for_process (struct process_info **childp, int *wstatp) |
| 560 | { |
| 561 | int ret; |
| 562 | int to_wait_for = -1; |
| 563 | |
| 564 | if (*childp != NULL) |
| 565 | to_wait_for = (*childp)->lwpid; |
| 566 | |
| 567 | retry: |
| 568 | while (1) |
| 569 | { |
| 570 | ret = waitpid (to_wait_for, wstatp, WNOHANG); |
| 571 | |
| 572 | if (ret == -1) |
| 573 | { |
| 574 | if (errno != ECHILD) |
| 575 | perror_with_name ("waitpid"); |
| 576 | } |
| 577 | else if (ret > 0) |
| 578 | break; |
| 579 | |
| 580 | ret = waitpid (to_wait_for, wstatp, WNOHANG | __WCLONE); |
| 581 | |
| 582 | if (ret == -1) |
| 583 | { |
| 584 | if (errno != ECHILD) |
| 585 | perror_with_name ("waitpid (WCLONE)"); |
| 586 | } |
| 587 | else if (ret > 0) |
| 588 | break; |
| 589 | |
| 590 | usleep (1000); |
| 591 | } |
| 592 | |
| 593 | if (debug_threads |
| 594 | && (!WIFSTOPPED (*wstatp) |
| 595 | || (WSTOPSIG (*wstatp) != 32 |
| 596 | && WSTOPSIG (*wstatp) != 33))) |
| 597 | fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp); |
| 598 | |
| 599 | if (to_wait_for == -1) |
| 600 | *childp = (struct process_info *) find_inferior_id (&all_processes, ret); |
| 601 | |
| 602 | /* If we didn't find a process, one of two things presumably happened: |
| 603 | - A process we started and then detached from has exited. Ignore it. |
| 604 | - A process we are controlling has forked and the new child's stop |
| 605 | was reported to us by the kernel. Save its PID. */ |
| 606 | if (*childp == NULL && WIFSTOPPED (*wstatp)) |
| 607 | { |
| 608 | add_pid_to_list (&stopped_pids, ret); |
| 609 | goto retry; |
| 610 | } |
| 611 | else if (*childp == NULL) |
| 612 | goto retry; |
| 613 | |
| 614 | (*childp)->stopped = 1; |
| 615 | (*childp)->pending_is_breakpoint = 0; |
| 616 | |
| 617 | (*childp)->last_status = *wstatp; |
| 618 | |
| 619 | if (debug_threads |
| 620 | && WIFSTOPPED (*wstatp)) |
| 621 | { |
| 622 | current_inferior = (struct thread_info *) |
| 623 | find_inferior_id (&all_threads, (*childp)->lwpid); |
| 624 | /* For testing only; i386_stop_pc prints out a diagnostic. */ |
| 625 | if (the_low_target.get_pc != NULL) |
| 626 | get_stop_pc (); |
| 627 | } |
| 628 | } |
| 629 | |
| 630 | static int |
| 631 | linux_wait_for_event (struct thread_info *child) |
| 632 | { |
| 633 | CORE_ADDR stop_pc; |
| 634 | struct process_info *event_child; |
| 635 | int wstat; |
| 636 | int bp_status; |
| 637 | |
| 638 | /* Check for a process with a pending status. */ |
| 639 | /* It is possible that the user changed the pending task's registers since |
| 640 | it stopped. We correctly handle the change of PC if we hit a breakpoint |
| 641 | (in check_removed_breakpoint); signals should be reported anyway. */ |
| 642 | if (child == NULL) |
| 643 | { |
| 644 | event_child = (struct process_info *) |
| 645 | find_inferior (&all_processes, status_pending_p, NULL); |
| 646 | if (debug_threads && event_child) |
| 647 | fprintf (stderr, "Got a pending child %ld\n", event_child->lwpid); |
| 648 | } |
| 649 | else |
| 650 | { |
| 651 | event_child = get_thread_process (child); |
| 652 | if (event_child->status_pending_p |
| 653 | && check_removed_breakpoint (event_child)) |
| 654 | event_child = NULL; |
| 655 | } |
| 656 | |
| 657 | if (event_child != NULL) |
| 658 | { |
| 659 | if (event_child->status_pending_p) |
| 660 | { |
| 661 | if (debug_threads) |
| 662 | fprintf (stderr, "Got an event from pending child %ld (%04x)\n", |
| 663 | event_child->lwpid, event_child->status_pending); |
| 664 | wstat = event_child->status_pending; |
| 665 | event_child->status_pending_p = 0; |
| 666 | event_child->status_pending = 0; |
| 667 | current_inferior = get_process_thread (event_child); |
| 668 | return wstat; |
| 669 | } |
| 670 | } |
| 671 | |
| 672 | /* We only enter this loop if no process has a pending wait status. Thus |
| 673 | any action taken in response to a wait status inside this loop is |
| 674 | responding as soon as we detect the status, not after any pending |
| 675 | events. */ |
| 676 | while (1) |
| 677 | { |
| 678 | if (child == NULL) |
| 679 | event_child = NULL; |
| 680 | else |
| 681 | event_child = get_thread_process (child); |
| 682 | |
| 683 | linux_wait_for_process (&event_child, &wstat); |
| 684 | |
| 685 | if (event_child == NULL) |
| 686 | error ("event from unknown child"); |
| 687 | |
| 688 | current_inferior = (struct thread_info *) |
| 689 | find_inferior_id (&all_threads, event_child->lwpid); |
| 690 | |
| 691 | /* Check for thread exit. */ |
| 692 | if (! WIFSTOPPED (wstat)) |
| 693 | { |
| 694 | if (debug_threads) |
| 695 | fprintf (stderr, "LWP %ld exiting\n", event_child->head.id); |
| 696 | |
| 697 | /* If the last thread is exiting, just return. */ |
| 698 | if (all_threads.head == all_threads.tail) |
| 699 | return wstat; |
| 700 | |
| 701 | dead_thread_notify (thread_id_to_gdb_id (event_child->lwpid)); |
| 702 | |
| 703 | remove_inferior (&all_processes, &event_child->head); |
| 704 | free (event_child); |
| 705 | remove_thread (current_inferior); |
| 706 | current_inferior = (struct thread_info *) all_threads.head; |
| 707 | |
| 708 | /* If we were waiting for this particular child to do something... |
| 709 | well, it did something. */ |
| 710 | if (child != NULL) |
| 711 | return wstat; |
| 712 | |
| 713 | /* Wait for a more interesting event. */ |
| 714 | continue; |
| 715 | } |
| 716 | |
| 717 | if (WIFSTOPPED (wstat) |
| 718 | && WSTOPSIG (wstat) == SIGSTOP |
| 719 | && event_child->stop_expected) |
| 720 | { |
| 721 | if (debug_threads) |
| 722 | fprintf (stderr, "Expected stop.\n"); |
| 723 | event_child->stop_expected = 0; |
| 724 | linux_resume_one_process (&event_child->head, |
| 725 | event_child->stepping, 0, NULL); |
| 726 | continue; |
| 727 | } |
| 728 | |
| 729 | if (WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SIGTRAP |
| 730 | && wstat >> 16 != 0) |
| 731 | { |
| 732 | handle_extended_wait (event_child, wstat); |
| 733 | continue; |
| 734 | } |
| 735 | |
| 736 | /* If GDB is not interested in this signal, don't stop other |
| 737 | threads, and don't report it to GDB. Just resume the |
| 738 | inferior right away. We do this for threading-related |
| 739 | signals as well as any that GDB specifically requested we |
| 740 | ignore. But never ignore SIGSTOP if we sent it ourselves, |
| 741 | and do not ignore signals when stepping - they may require |
| 742 | special handling to skip the signal handler. */ |
| 743 | /* FIXME drow/2002-06-09: Get signal numbers from the inferior's |
| 744 | thread library? */ |
| 745 | if (WIFSTOPPED (wstat) |
| 746 | && !event_child->stepping |
| 747 | && ( |
| 748 | #ifdef USE_THREAD_DB |
| 749 | (thread_db_active && (WSTOPSIG (wstat) == __SIGRTMIN |
| 750 | || WSTOPSIG (wstat) == __SIGRTMIN + 1)) |
| 751 | || |
| 752 | #endif |
| 753 | (pass_signals[target_signal_from_host (WSTOPSIG (wstat))] |
| 754 | && (WSTOPSIG (wstat) != SIGSTOP || !stopping_threads)))) |
| 755 | { |
| 756 | siginfo_t info, *info_p; |
| 757 | |
| 758 | if (debug_threads) |
| 759 | fprintf (stderr, "Ignored signal %d for LWP %ld.\n", |
| 760 | WSTOPSIG (wstat), event_child->head.id); |
| 761 | |
| 762 | if (ptrace (PTRACE_GETSIGINFO, event_child->lwpid, 0, &info) == 0) |
| 763 | info_p = &info; |
| 764 | else |
| 765 | info_p = NULL; |
| 766 | linux_resume_one_process (&event_child->head, |
| 767 | event_child->stepping, |
| 768 | WSTOPSIG (wstat), info_p); |
| 769 | continue; |
| 770 | } |
| 771 | |
| 772 | /* If this event was not handled above, and is not a SIGTRAP, report |
| 773 | it. */ |
| 774 | if (!WIFSTOPPED (wstat) || WSTOPSIG (wstat) != SIGTRAP) |
| 775 | return wstat; |
| 776 | |
| 777 | /* If this target does not support breakpoints, we simply report the |
| 778 | SIGTRAP; it's of no concern to us. */ |
| 779 | if (the_low_target.get_pc == NULL) |
| 780 | return wstat; |
| 781 | |
| 782 | stop_pc = get_stop_pc (); |
| 783 | |
| 784 | /* bp_reinsert will only be set if we were single-stepping. |
| 785 | Notice that we will resume the process after hitting |
| 786 | a gdbserver breakpoint; single-stepping to/over one |
| 787 | is not supported (yet). */ |
| 788 | if (event_child->bp_reinsert != 0) |
| 789 | { |
| 790 | if (debug_threads) |
| 791 | fprintf (stderr, "Reinserted breakpoint.\n"); |
| 792 | reinsert_breakpoint (event_child->bp_reinsert); |
| 793 | event_child->bp_reinsert = 0; |
| 794 | |
| 795 | /* Clear the single-stepping flag and SIGTRAP as we resume. */ |
| 796 | linux_resume_one_process (&event_child->head, 0, 0, NULL); |
| 797 | continue; |
| 798 | } |
| 799 | |
| 800 | bp_status = check_breakpoints (stop_pc); |
| 801 | |
| 802 | if (bp_status != 0) |
| 803 | { |
| 804 | if (debug_threads) |
| 805 | fprintf (stderr, "Hit a gdbserver breakpoint.\n"); |
| 806 | |
| 807 | /* We hit one of our own breakpoints. We mark it as a pending |
| 808 | breakpoint, so that check_removed_breakpoint () will do the PC |
| 809 | adjustment for us at the appropriate time. */ |
| 810 | event_child->pending_is_breakpoint = 1; |
| 811 | event_child->pending_stop_pc = stop_pc; |
| 812 | |
| 813 | /* We may need to put the breakpoint back. We continue in the event |
| 814 | loop instead of simply replacing the breakpoint right away, |
| 815 | in order to not lose signals sent to the thread that hit the |
| 816 | breakpoint. Unfortunately this increases the window where another |
| 817 | thread could sneak past the removed breakpoint. For the current |
| 818 | use of server-side breakpoints (thread creation) this is |
| 819 | acceptable; but it needs to be considered before this breakpoint |
| 820 | mechanism can be used in more general ways. For some breakpoints |
| 821 | it may be necessary to stop all other threads, but that should |
| 822 | be avoided where possible. |
| 823 | |
| 824 | If breakpoint_reinsert_addr is NULL, that means that we can |
| 825 | use PTRACE_SINGLESTEP on this platform. Uninsert the breakpoint, |
| 826 | mark it for reinsertion, and single-step. |
| 827 | |
| 828 | Otherwise, call the target function to figure out where we need |
| 829 | our temporary breakpoint, create it, and continue executing this |
| 830 | process. */ |
| 831 | if (bp_status == 2) |
| 832 | /* No need to reinsert. */ |
| 833 | linux_resume_one_process (&event_child->head, 0, 0, NULL); |
| 834 | else if (the_low_target.breakpoint_reinsert_addr == NULL) |
| 835 | { |
| 836 | event_child->bp_reinsert = stop_pc; |
| 837 | uninsert_breakpoint (stop_pc); |
| 838 | linux_resume_one_process (&event_child->head, 1, 0, NULL); |
| 839 | } |
| 840 | else |
| 841 | { |
| 842 | reinsert_breakpoint_by_bp |
| 843 | (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ()); |
| 844 | linux_resume_one_process (&event_child->head, 0, 0, NULL); |
| 845 | } |
| 846 | |
| 847 | continue; |
| 848 | } |
| 849 | |
| 850 | if (debug_threads) |
| 851 | fprintf (stderr, "Hit a non-gdbserver breakpoint.\n"); |
| 852 | |
| 853 | /* If we were single-stepping, we definitely want to report the |
| 854 | SIGTRAP. The single-step operation has completed, so also |
| 855 | clear the stepping flag; in general this does not matter, |
| 856 | because the SIGTRAP will be reported to the client, which |
| 857 | will give us a new action for this thread, but clear it for |
| 858 | consistency anyway. It's safe to clear the stepping flag |
| 859 | because the only consumer of get_stop_pc () after this point |
| 860 | is check_removed_breakpoint, and pending_is_breakpoint is not |
| 861 | set. It might be wiser to use a step_completed flag instead. */ |
| 862 | if (event_child->stepping) |
| 863 | { |
| 864 | event_child->stepping = 0; |
| 865 | return wstat; |
| 866 | } |
| 867 | |
| 868 | /* A SIGTRAP that we can't explain. It may have been a breakpoint. |
| 869 | Check if it is a breakpoint, and if so mark the process information |
| 870 | accordingly. This will handle both the necessary fiddling with the |
| 871 | PC on decr_pc_after_break targets and suppressing extra threads |
| 872 | hitting a breakpoint if two hit it at once and then GDB removes it |
| 873 | after the first is reported. Arguably it would be better to report |
| 874 | multiple threads hitting breakpoints simultaneously, but the current |
| 875 | remote protocol does not allow this. */ |
| 876 | if ((*the_low_target.breakpoint_at) (stop_pc)) |
| 877 | { |
| 878 | event_child->pending_is_breakpoint = 1; |
| 879 | event_child->pending_stop_pc = stop_pc; |
| 880 | } |
| 881 | |
| 882 | return wstat; |
| 883 | } |
| 884 | |
| 885 | /* NOTREACHED */ |
| 886 | return 0; |
| 887 | } |
| 888 | |
| 889 | /* Wait for process, returns status. */ |
| 890 | |
| 891 | static unsigned char |
| 892 | linux_wait (char *status) |
| 893 | { |
| 894 | int w; |
| 895 | struct thread_info *child = NULL; |
| 896 | |
| 897 | retry: |
| 898 | /* If we were only supposed to resume one thread, only wait for |
| 899 | that thread - if it's still alive. If it died, however - which |
| 900 | can happen if we're coming from the thread death case below - |
| 901 | then we need to make sure we restart the other threads. We could |
| 902 | pick a thread at random or restart all; restarting all is less |
| 903 | arbitrary. */ |
| 904 | if (cont_thread != 0 && cont_thread != -1) |
| 905 | { |
| 906 | child = (struct thread_info *) find_inferior_id (&all_threads, |
| 907 | cont_thread); |
| 908 | |
| 909 | /* No stepping, no signal - unless one is pending already, of course. */ |
| 910 | if (child == NULL) |
| 911 | { |
| 912 | struct thread_resume resume_info; |
| 913 | resume_info.thread = -1; |
| 914 | resume_info.step = resume_info.sig = resume_info.leave_stopped = 0; |
| 915 | linux_resume (&resume_info); |
| 916 | } |
| 917 | } |
| 918 | |
| 919 | w = linux_wait_for_event (child); |
| 920 | stop_all_processes (); |
| 921 | |
| 922 | if (must_set_ptrace_flags) |
| 923 | { |
| 924 | ptrace (PTRACE_SETOPTIONS, inferior_pid, 0, PTRACE_O_TRACECLONE); |
| 925 | must_set_ptrace_flags = 0; |
| 926 | } |
| 927 | |
| 928 | /* If we are waiting for a particular child, and it exited, |
| 929 | linux_wait_for_event will return its exit status. Similarly if |
| 930 | the last child exited. If this is not the last child, however, |
| 931 | do not report it as exited until there is a 'thread exited' response |
| 932 | available in the remote protocol. Instead, just wait for another event. |
| 933 | This should be safe, because if the thread crashed we will already |
| 934 | have reported the termination signal to GDB; that should stop any |
| 935 | in-progress stepping operations, etc. |
| 936 | |
| 937 | Report the exit status of the last thread to exit. This matches |
| 938 | LinuxThreads' behavior. */ |
| 939 | |
| 940 | if (all_threads.head == all_threads.tail) |
| 941 | { |
| 942 | if (WIFEXITED (w)) |
| 943 | { |
| 944 | fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w)); |
| 945 | *status = 'W'; |
| 946 | clear_inferiors (); |
| 947 | free (all_processes.head); |
| 948 | all_processes.head = all_processes.tail = NULL; |
| 949 | return WEXITSTATUS (w); |
| 950 | } |
| 951 | else if (!WIFSTOPPED (w)) |
| 952 | { |
| 953 | fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w)); |
| 954 | *status = 'X'; |
| 955 | clear_inferiors (); |
| 956 | free (all_processes.head); |
| 957 | all_processes.head = all_processes.tail = NULL; |
| 958 | return target_signal_from_host (WTERMSIG (w)); |
| 959 | } |
| 960 | } |
| 961 | else |
| 962 | { |
| 963 | if (!WIFSTOPPED (w)) |
| 964 | goto retry; |
| 965 | } |
| 966 | |
| 967 | *status = 'T'; |
| 968 | return target_signal_from_host (WSTOPSIG (w)); |
| 969 | } |
| 970 | |
| 971 | /* Send a signal to an LWP. For LinuxThreads, kill is enough; however, if |
| 972 | thread groups are in use, we need to use tkill. */ |
| 973 | |
| 974 | static int |
| 975 | kill_lwp (unsigned long lwpid, int signo) |
| 976 | { |
| 977 | static int tkill_failed; |
| 978 | |
| 979 | errno = 0; |
| 980 | |
| 981 | #ifdef SYS_tkill |
| 982 | if (!tkill_failed) |
| 983 | { |
| 984 | int ret = syscall (SYS_tkill, lwpid, signo); |
| 985 | if (errno != ENOSYS) |
| 986 | return ret; |
| 987 | errno = 0; |
| 988 | tkill_failed = 1; |
| 989 | } |
| 990 | #endif |
| 991 | |
| 992 | return kill (lwpid, signo); |
| 993 | } |
| 994 | |
| 995 | static void |
| 996 | send_sigstop (struct inferior_list_entry *entry) |
| 997 | { |
| 998 | struct process_info *process = (struct process_info *) entry; |
| 999 | |
| 1000 | if (process->stopped) |
| 1001 | return; |
| 1002 | |
| 1003 | /* If we already have a pending stop signal for this process, don't |
| 1004 | send another. */ |
| 1005 | if (process->stop_expected) |
| 1006 | { |
| 1007 | if (debug_threads) |
| 1008 | fprintf (stderr, "Have pending sigstop for process %ld\n", |
| 1009 | process->lwpid); |
| 1010 | |
| 1011 | /* We clear the stop_expected flag so that wait_for_sigstop |
| 1012 | will receive the SIGSTOP event (instead of silently resuming and |
| 1013 | waiting again). It'll be reset below. */ |
| 1014 | process->stop_expected = 0; |
| 1015 | return; |
| 1016 | } |
| 1017 | |
| 1018 | if (debug_threads) |
| 1019 | fprintf (stderr, "Sending sigstop to process %ld\n", process->head.id); |
| 1020 | |
| 1021 | kill_lwp (process->head.id, SIGSTOP); |
| 1022 | } |
| 1023 | |
| 1024 | static void |
| 1025 | wait_for_sigstop (struct inferior_list_entry *entry) |
| 1026 | { |
| 1027 | struct process_info *process = (struct process_info *) entry; |
| 1028 | struct thread_info *saved_inferior, *thread; |
| 1029 | int wstat; |
| 1030 | unsigned long saved_tid; |
| 1031 | |
| 1032 | if (process->stopped) |
| 1033 | return; |
| 1034 | |
| 1035 | saved_inferior = current_inferior; |
| 1036 | saved_tid = ((struct inferior_list_entry *) saved_inferior)->id; |
| 1037 | thread = (struct thread_info *) find_inferior_id (&all_threads, |
| 1038 | process->lwpid); |
| 1039 | wstat = linux_wait_for_event (thread); |
| 1040 | |
| 1041 | /* If we stopped with a non-SIGSTOP signal, save it for later |
| 1042 | and record the pending SIGSTOP. If the process exited, just |
| 1043 | return. */ |
| 1044 | if (WIFSTOPPED (wstat) |
| 1045 | && WSTOPSIG (wstat) != SIGSTOP) |
| 1046 | { |
| 1047 | if (debug_threads) |
| 1048 | fprintf (stderr, "LWP %ld stopped with non-sigstop status %06x\n", |
| 1049 | process->lwpid, wstat); |
| 1050 | process->status_pending_p = 1; |
| 1051 | process->status_pending = wstat; |
| 1052 | process->stop_expected = 1; |
| 1053 | } |
| 1054 | |
| 1055 | if (linux_thread_alive (saved_tid)) |
| 1056 | current_inferior = saved_inferior; |
| 1057 | else |
| 1058 | { |
| 1059 | if (debug_threads) |
| 1060 | fprintf (stderr, "Previously current thread died.\n"); |
| 1061 | |
| 1062 | /* Set a valid thread as current. */ |
| 1063 | set_desired_inferior (0); |
| 1064 | } |
| 1065 | } |
| 1066 | |
| 1067 | static void |
| 1068 | stop_all_processes (void) |
| 1069 | { |
| 1070 | stopping_threads = 1; |
| 1071 | for_each_inferior (&all_processes, send_sigstop); |
| 1072 | for_each_inferior (&all_processes, wait_for_sigstop); |
| 1073 | stopping_threads = 0; |
| 1074 | } |
| 1075 | |
| 1076 | /* Resume execution of the inferior process. |
| 1077 | If STEP is nonzero, single-step it. |
| 1078 | If SIGNAL is nonzero, give it that signal. */ |
| 1079 | |
| 1080 | static void |
| 1081 | linux_resume_one_process (struct inferior_list_entry *entry, |
| 1082 | int step, int signal, siginfo_t *info) |
| 1083 | { |
| 1084 | struct process_info *process = (struct process_info *) entry; |
| 1085 | struct thread_info *saved_inferior; |
| 1086 | |
| 1087 | if (process->stopped == 0) |
| 1088 | return; |
| 1089 | |
| 1090 | /* If we have pending signals or status, and a new signal, enqueue the |
| 1091 | signal. Also enqueue the signal if we are waiting to reinsert a |
| 1092 | breakpoint; it will be picked up again below. */ |
| 1093 | if (signal != 0 |
| 1094 | && (process->status_pending_p || process->pending_signals != NULL |
| 1095 | || process->bp_reinsert != 0)) |
| 1096 | { |
| 1097 | struct pending_signals *p_sig; |
| 1098 | p_sig = malloc (sizeof (*p_sig)); |
| 1099 | p_sig->prev = process->pending_signals; |
| 1100 | p_sig->signal = signal; |
| 1101 | if (info == NULL) |
| 1102 | memset (&p_sig->info, 0, sizeof (siginfo_t)); |
| 1103 | else |
| 1104 | memcpy (&p_sig->info, info, sizeof (siginfo_t)); |
| 1105 | process->pending_signals = p_sig; |
| 1106 | } |
| 1107 | |
| 1108 | if (process->status_pending_p && !check_removed_breakpoint (process)) |
| 1109 | return; |
| 1110 | |
| 1111 | saved_inferior = current_inferior; |
| 1112 | current_inferior = get_process_thread (process); |
| 1113 | |
| 1114 | if (debug_threads) |
| 1115 | fprintf (stderr, "Resuming process %ld (%s, signal %d, stop %s)\n", inferior_pid, |
| 1116 | step ? "step" : "continue", signal, |
| 1117 | process->stop_expected ? "expected" : "not expected"); |
| 1118 | |
| 1119 | /* This bit needs some thinking about. If we get a signal that |
| 1120 | we must report while a single-step reinsert is still pending, |
| 1121 | we often end up resuming the thread. It might be better to |
| 1122 | (ew) allow a stack of pending events; then we could be sure that |
| 1123 | the reinsert happened right away and not lose any signals. |
| 1124 | |
| 1125 | Making this stack would also shrink the window in which breakpoints are |
| 1126 | uninserted (see comment in linux_wait_for_process) but not enough for |
| 1127 | complete correctness, so it won't solve that problem. It may be |
| 1128 | worthwhile just to solve this one, however. */ |
| 1129 | if (process->bp_reinsert != 0) |
| 1130 | { |
| 1131 | if (debug_threads) |
| 1132 | fprintf (stderr, " pending reinsert at %08lx", (long)process->bp_reinsert); |
| 1133 | if (step == 0) |
| 1134 | fprintf (stderr, "BAD - reinserting but not stepping.\n"); |
| 1135 | step = 1; |
| 1136 | |
| 1137 | /* Postpone any pending signal. It was enqueued above. */ |
| 1138 | signal = 0; |
| 1139 | } |
| 1140 | |
| 1141 | check_removed_breakpoint (process); |
| 1142 | |
| 1143 | if (debug_threads && the_low_target.get_pc != NULL) |
| 1144 | { |
| 1145 | fprintf (stderr, " "); |
| 1146 | (*the_low_target.get_pc) (); |
| 1147 | } |
| 1148 | |
| 1149 | /* If we have pending signals, consume one unless we are trying to reinsert |
| 1150 | a breakpoint. */ |
| 1151 | if (process->pending_signals != NULL && process->bp_reinsert == 0) |
| 1152 | { |
| 1153 | struct pending_signals **p_sig; |
| 1154 | |
| 1155 | p_sig = &process->pending_signals; |
| 1156 | while ((*p_sig)->prev != NULL) |
| 1157 | p_sig = &(*p_sig)->prev; |
| 1158 | |
| 1159 | signal = (*p_sig)->signal; |
| 1160 | if ((*p_sig)->info.si_signo != 0) |
| 1161 | ptrace (PTRACE_SETSIGINFO, process->lwpid, 0, &(*p_sig)->info); |
| 1162 | |
| 1163 | free (*p_sig); |
| 1164 | *p_sig = NULL; |
| 1165 | } |
| 1166 | |
| 1167 | regcache_invalidate_one ((struct inferior_list_entry *) |
| 1168 | get_process_thread (process)); |
| 1169 | errno = 0; |
| 1170 | process->stopped = 0; |
| 1171 | process->stepping = step; |
| 1172 | ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, process->lwpid, 0, signal); |
| 1173 | |
| 1174 | current_inferior = saved_inferior; |
| 1175 | if (errno) |
| 1176 | perror_with_name ("ptrace"); |
| 1177 | } |
| 1178 | |
| 1179 | static struct thread_resume *resume_ptr; |
| 1180 | |
| 1181 | /* This function is called once per thread. We look up the thread |
| 1182 | in RESUME_PTR, and mark the thread with a pointer to the appropriate |
| 1183 | resume request. |
| 1184 | |
| 1185 | This algorithm is O(threads * resume elements), but resume elements |
| 1186 | is small (and will remain small at least until GDB supports thread |
| 1187 | suspension). */ |
| 1188 | static void |
| 1189 | linux_set_resume_request (struct inferior_list_entry *entry) |
| 1190 | { |
| 1191 | struct process_info *process; |
| 1192 | struct thread_info *thread; |
| 1193 | int ndx; |
| 1194 | |
| 1195 | thread = (struct thread_info *) entry; |
| 1196 | process = get_thread_process (thread); |
| 1197 | |
| 1198 | ndx = 0; |
| 1199 | while (resume_ptr[ndx].thread != -1 && resume_ptr[ndx].thread != entry->id) |
| 1200 | ndx++; |
| 1201 | |
| 1202 | process->resume = &resume_ptr[ndx]; |
| 1203 | } |
| 1204 | |
| 1205 | /* This function is called once per thread. We check the thread's resume |
| 1206 | request, which will tell us whether to resume, step, or leave the thread |
| 1207 | stopped; and what signal, if any, it should be sent. For threads which |
| 1208 | we aren't explicitly told otherwise, we preserve the stepping flag; this |
| 1209 | is used for stepping over gdbserver-placed breakpoints. */ |
| 1210 | |
| 1211 | static void |
| 1212 | linux_continue_one_thread (struct inferior_list_entry *entry) |
| 1213 | { |
| 1214 | struct process_info *process; |
| 1215 | struct thread_info *thread; |
| 1216 | int step; |
| 1217 | |
| 1218 | thread = (struct thread_info *) entry; |
| 1219 | process = get_thread_process (thread); |
| 1220 | |
| 1221 | if (process->resume->leave_stopped) |
| 1222 | return; |
| 1223 | |
| 1224 | if (process->resume->thread == -1) |
| 1225 | step = process->stepping || process->resume->step; |
| 1226 | else |
| 1227 | step = process->resume->step; |
| 1228 | |
| 1229 | linux_resume_one_process (&process->head, step, process->resume->sig, NULL); |
| 1230 | |
| 1231 | process->resume = NULL; |
| 1232 | } |
| 1233 | |
| 1234 | /* This function is called once per thread. We check the thread's resume |
| 1235 | request, which will tell us whether to resume, step, or leave the thread |
| 1236 | stopped; and what signal, if any, it should be sent. We queue any needed |
| 1237 | signals, since we won't actually resume. We already have a pending event |
| 1238 | to report, so we don't need to preserve any step requests; they should |
| 1239 | be re-issued if necessary. */ |
| 1240 | |
| 1241 | static void |
| 1242 | linux_queue_one_thread (struct inferior_list_entry *entry) |
| 1243 | { |
| 1244 | struct process_info *process; |
| 1245 | struct thread_info *thread; |
| 1246 | |
| 1247 | thread = (struct thread_info *) entry; |
| 1248 | process = get_thread_process (thread); |
| 1249 | |
| 1250 | if (process->resume->leave_stopped) |
| 1251 | return; |
| 1252 | |
| 1253 | /* If we have a new signal, enqueue the signal. */ |
| 1254 | if (process->resume->sig != 0) |
| 1255 | { |
| 1256 | struct pending_signals *p_sig; |
| 1257 | p_sig = malloc (sizeof (*p_sig)); |
| 1258 | p_sig->prev = process->pending_signals; |
| 1259 | p_sig->signal = process->resume->sig; |
| 1260 | memset (&p_sig->info, 0, sizeof (siginfo_t)); |
| 1261 | |
| 1262 | /* If this is the same signal we were previously stopped by, |
| 1263 | make sure to queue its siginfo. We can ignore the return |
| 1264 | value of ptrace; if it fails, we'll skip |
| 1265 | PTRACE_SETSIGINFO. */ |
| 1266 | if (WIFSTOPPED (process->last_status) |
| 1267 | && WSTOPSIG (process->last_status) == process->resume->sig) |
| 1268 | ptrace (PTRACE_GETSIGINFO, process->lwpid, 0, &p_sig->info); |
| 1269 | |
| 1270 | process->pending_signals = p_sig; |
| 1271 | } |
| 1272 | |
| 1273 | process->resume = NULL; |
| 1274 | } |
| 1275 | |
| 1276 | /* Set DUMMY if this process has an interesting status pending. */ |
| 1277 | static int |
| 1278 | resume_status_pending_p (struct inferior_list_entry *entry, void *flag_p) |
| 1279 | { |
| 1280 | struct process_info *process = (struct process_info *) entry; |
| 1281 | |
| 1282 | /* Processes which will not be resumed are not interesting, because |
| 1283 | we might not wait for them next time through linux_wait. */ |
| 1284 | if (process->resume->leave_stopped) |
| 1285 | return 0; |
| 1286 | |
| 1287 | /* If this thread has a removed breakpoint, we won't have any |
| 1288 | events to report later, so check now. check_removed_breakpoint |
| 1289 | may clear status_pending_p. We avoid calling check_removed_breakpoint |
| 1290 | for any thread that we are not otherwise going to resume - this |
| 1291 | lets us preserve stopped status when two threads hit a breakpoint. |
| 1292 | GDB removes the breakpoint to single-step a particular thread |
| 1293 | past it, then re-inserts it and resumes all threads. We want |
| 1294 | to report the second thread without resuming it in the interim. */ |
| 1295 | if (process->status_pending_p) |
| 1296 | check_removed_breakpoint (process); |
| 1297 | |
| 1298 | if (process->status_pending_p) |
| 1299 | * (int *) flag_p = 1; |
| 1300 | |
| 1301 | return 0; |
| 1302 | } |
| 1303 | |
| 1304 | static void |
| 1305 | linux_resume (struct thread_resume *resume_info) |
| 1306 | { |
| 1307 | int pending_flag; |
| 1308 | |
| 1309 | /* Yes, the use of a global here is rather ugly. */ |
| 1310 | resume_ptr = resume_info; |
| 1311 | |
| 1312 | for_each_inferior (&all_threads, linux_set_resume_request); |
| 1313 | |
| 1314 | /* If there is a thread which would otherwise be resumed, which |
| 1315 | has a pending status, then don't resume any threads - we can just |
| 1316 | report the pending status. Make sure to queue any signals |
| 1317 | that would otherwise be sent. */ |
| 1318 | pending_flag = 0; |
| 1319 | find_inferior (&all_processes, resume_status_pending_p, &pending_flag); |
| 1320 | |
| 1321 | if (debug_threads) |
| 1322 | { |
| 1323 | if (pending_flag) |
| 1324 | fprintf (stderr, "Not resuming, pending status\n"); |
| 1325 | else |
| 1326 | fprintf (stderr, "Resuming, no pending status\n"); |
| 1327 | } |
| 1328 | |
| 1329 | if (pending_flag) |
| 1330 | for_each_inferior (&all_threads, linux_queue_one_thread); |
| 1331 | else |
| 1332 | for_each_inferior (&all_threads, linux_continue_one_thread); |
| 1333 | } |
| 1334 | |
| 1335 | #ifdef HAVE_LINUX_USRREGS |
| 1336 | |
| 1337 | int |
| 1338 | register_addr (int regnum) |
| 1339 | { |
| 1340 | int addr; |
| 1341 | |
| 1342 | if (regnum < 0 || regnum >= the_low_target.num_regs) |
| 1343 | error ("Invalid register number %d.", regnum); |
| 1344 | |
| 1345 | addr = the_low_target.regmap[regnum]; |
| 1346 | |
| 1347 | return addr; |
| 1348 | } |
| 1349 | |
| 1350 | /* Fetch one register. */ |
| 1351 | static void |
| 1352 | fetch_register (int regno) |
| 1353 | { |
| 1354 | CORE_ADDR regaddr; |
| 1355 | int i, size; |
| 1356 | char *buf; |
| 1357 | |
| 1358 | if (regno >= the_low_target.num_regs) |
| 1359 | return; |
| 1360 | if ((*the_low_target.cannot_fetch_register) (regno)) |
| 1361 | return; |
| 1362 | |
| 1363 | regaddr = register_addr (regno); |
| 1364 | if (regaddr == -1) |
| 1365 | return; |
| 1366 | size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1) |
| 1367 | & - sizeof (PTRACE_XFER_TYPE); |
| 1368 | buf = alloca (size); |
| 1369 | for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE)) |
| 1370 | { |
| 1371 | errno = 0; |
| 1372 | *(PTRACE_XFER_TYPE *) (buf + i) = |
| 1373 | ptrace (PTRACE_PEEKUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0); |
| 1374 | regaddr += sizeof (PTRACE_XFER_TYPE); |
| 1375 | if (errno != 0) |
| 1376 | { |
| 1377 | /* Warning, not error, in case we are attached; sometimes the |
| 1378 | kernel doesn't let us at the registers. */ |
| 1379 | char *err = strerror (errno); |
| 1380 | char *msg = alloca (strlen (err) + 128); |
| 1381 | sprintf (msg, "reading register %d: %s", regno, err); |
| 1382 | error (msg); |
| 1383 | goto error_exit; |
| 1384 | } |
| 1385 | } |
| 1386 | if (the_low_target.left_pad_xfer |
| 1387 | && register_size (regno) < sizeof (PTRACE_XFER_TYPE)) |
| 1388 | supply_register (regno, (buf + sizeof (PTRACE_XFER_TYPE) |
| 1389 | - register_size (regno))); |
| 1390 | else |
| 1391 | supply_register (regno, buf); |
| 1392 | |
| 1393 | error_exit:; |
| 1394 | } |
| 1395 | |
| 1396 | /* Fetch all registers, or just one, from the child process. */ |
| 1397 | static void |
| 1398 | usr_fetch_inferior_registers (int regno) |
| 1399 | { |
| 1400 | if (regno == -1 || regno == 0) |
| 1401 | for (regno = 0; regno < the_low_target.num_regs; regno++) |
| 1402 | fetch_register (regno); |
| 1403 | else |
| 1404 | fetch_register (regno); |
| 1405 | } |
| 1406 | |
| 1407 | /* Store our register values back into the inferior. |
| 1408 | If REGNO is -1, do this for all registers. |
| 1409 | Otherwise, REGNO specifies which register (so we can save time). */ |
| 1410 | static void |
| 1411 | usr_store_inferior_registers (int regno) |
| 1412 | { |
| 1413 | CORE_ADDR regaddr; |
| 1414 | int i, size; |
| 1415 | char *buf; |
| 1416 | |
| 1417 | if (regno >= 0) |
| 1418 | { |
| 1419 | if (regno >= the_low_target.num_regs) |
| 1420 | return; |
| 1421 | |
| 1422 | if ((*the_low_target.cannot_store_register) (regno) == 1) |
| 1423 | return; |
| 1424 | |
| 1425 | regaddr = register_addr (regno); |
| 1426 | if (regaddr == -1) |
| 1427 | return; |
| 1428 | errno = 0; |
| 1429 | size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1) |
| 1430 | & - sizeof (PTRACE_XFER_TYPE); |
| 1431 | buf = alloca (size); |
| 1432 | memset (buf, 0, size); |
| 1433 | if (the_low_target.left_pad_xfer |
| 1434 | && register_size (regno) < sizeof (PTRACE_XFER_TYPE)) |
| 1435 | collect_register (regno, (buf + sizeof (PTRACE_XFER_TYPE) |
| 1436 | - register_size (regno))); |
| 1437 | else |
| 1438 | collect_register (regno, buf); |
| 1439 | for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE)) |
| 1440 | { |
| 1441 | errno = 0; |
| 1442 | ptrace (PTRACE_POKEUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, |
| 1443 | *(PTRACE_XFER_TYPE *) (buf + i)); |
| 1444 | if (errno != 0) |
| 1445 | { |
| 1446 | if ((*the_low_target.cannot_store_register) (regno) == 0) |
| 1447 | { |
| 1448 | char *err = strerror (errno); |
| 1449 | char *msg = alloca (strlen (err) + 128); |
| 1450 | sprintf (msg, "writing register %d: %s", |
| 1451 | regno, err); |
| 1452 | error (msg); |
| 1453 | return; |
| 1454 | } |
| 1455 | } |
| 1456 | regaddr += sizeof (PTRACE_XFER_TYPE); |
| 1457 | } |
| 1458 | } |
| 1459 | else |
| 1460 | for (regno = 0; regno < the_low_target.num_regs; regno++) |
| 1461 | usr_store_inferior_registers (regno); |
| 1462 | } |
| 1463 | #endif /* HAVE_LINUX_USRREGS */ |
| 1464 | |
| 1465 | |
| 1466 | |
| 1467 | #ifdef HAVE_LINUX_REGSETS |
| 1468 | |
| 1469 | static int |
| 1470 | regsets_fetch_inferior_registers () |
| 1471 | { |
| 1472 | struct regset_info *regset; |
| 1473 | int saw_general_regs = 0; |
| 1474 | |
| 1475 | regset = target_regsets; |
| 1476 | |
| 1477 | while (regset->size >= 0) |
| 1478 | { |
| 1479 | void *buf; |
| 1480 | int res; |
| 1481 | |
| 1482 | if (regset->size == 0) |
| 1483 | { |
| 1484 | regset ++; |
| 1485 | continue; |
| 1486 | } |
| 1487 | |
| 1488 | buf = malloc (regset->size); |
| 1489 | res = ptrace (regset->get_request, inferior_pid, 0, buf); |
| 1490 | if (res < 0) |
| 1491 | { |
| 1492 | if (errno == EIO) |
| 1493 | { |
| 1494 | /* If we get EIO on the first regset, do not try regsets again. |
| 1495 | If we get EIO on a later regset, disable that regset. */ |
| 1496 | if (regset == target_regsets) |
| 1497 | { |
| 1498 | use_regsets_p = 0; |
| 1499 | return -1; |
| 1500 | } |
| 1501 | else |
| 1502 | { |
| 1503 | regset->size = 0; |
| 1504 | continue; |
| 1505 | } |
| 1506 | } |
| 1507 | else |
| 1508 | { |
| 1509 | char s[256]; |
| 1510 | sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%ld", |
| 1511 | inferior_pid); |
| 1512 | perror (s); |
| 1513 | } |
| 1514 | } |
| 1515 | else if (regset->type == GENERAL_REGS) |
| 1516 | saw_general_regs = 1; |
| 1517 | regset->store_function (buf); |
| 1518 | regset ++; |
| 1519 | } |
| 1520 | if (saw_general_regs) |
| 1521 | return 0; |
| 1522 | else |
| 1523 | return 1; |
| 1524 | } |
| 1525 | |
| 1526 | static int |
| 1527 | regsets_store_inferior_registers () |
| 1528 | { |
| 1529 | struct regset_info *regset; |
| 1530 | int saw_general_regs = 0; |
| 1531 | |
| 1532 | regset = target_regsets; |
| 1533 | |
| 1534 | while (regset->size >= 0) |
| 1535 | { |
| 1536 | void *buf; |
| 1537 | int res; |
| 1538 | |
| 1539 | if (regset->size == 0) |
| 1540 | { |
| 1541 | regset ++; |
| 1542 | continue; |
| 1543 | } |
| 1544 | |
| 1545 | buf = malloc (regset->size); |
| 1546 | |
| 1547 | /* First fill the buffer with the current register set contents, |
| 1548 | in case there are any items in the kernel's regset that are |
| 1549 | not in gdbserver's regcache. */ |
| 1550 | res = ptrace (regset->get_request, inferior_pid, 0, buf); |
| 1551 | |
| 1552 | if (res == 0) |
| 1553 | { |
| 1554 | /* Then overlay our cached registers on that. */ |
| 1555 | regset->fill_function (buf); |
| 1556 | |
| 1557 | /* Only now do we write the register set. */ |
| 1558 | res = ptrace (regset->set_request, inferior_pid, 0, buf); |
| 1559 | } |
| 1560 | |
| 1561 | if (res < 0) |
| 1562 | { |
| 1563 | if (errno == EIO) |
| 1564 | { |
| 1565 | /* If we get EIO on the first regset, do not try regsets again. |
| 1566 | If we get EIO on a later regset, disable that regset. */ |
| 1567 | if (regset == target_regsets) |
| 1568 | { |
| 1569 | use_regsets_p = 0; |
| 1570 | return -1; |
| 1571 | } |
| 1572 | else |
| 1573 | { |
| 1574 | regset->size = 0; |
| 1575 | continue; |
| 1576 | } |
| 1577 | } |
| 1578 | else |
| 1579 | { |
| 1580 | perror ("Warning: ptrace(regsets_store_inferior_registers)"); |
| 1581 | } |
| 1582 | } |
| 1583 | else if (regset->type == GENERAL_REGS) |
| 1584 | saw_general_regs = 1; |
| 1585 | regset ++; |
| 1586 | free (buf); |
| 1587 | } |
| 1588 | if (saw_general_regs) |
| 1589 | return 0; |
| 1590 | else |
| 1591 | return 1; |
| 1592 | return 0; |
| 1593 | } |
| 1594 | |
| 1595 | #endif /* HAVE_LINUX_REGSETS */ |
| 1596 | |
| 1597 | |
| 1598 | void |
| 1599 | linux_fetch_registers (int regno) |
| 1600 | { |
| 1601 | #ifdef HAVE_LINUX_REGSETS |
| 1602 | if (use_regsets_p) |
| 1603 | { |
| 1604 | if (regsets_fetch_inferior_registers () == 0) |
| 1605 | return; |
| 1606 | } |
| 1607 | #endif |
| 1608 | #ifdef HAVE_LINUX_USRREGS |
| 1609 | usr_fetch_inferior_registers (regno); |
| 1610 | #endif |
| 1611 | } |
| 1612 | |
| 1613 | void |
| 1614 | linux_store_registers (int regno) |
| 1615 | { |
| 1616 | #ifdef HAVE_LINUX_REGSETS |
| 1617 | if (use_regsets_p) |
| 1618 | { |
| 1619 | if (regsets_store_inferior_registers () == 0) |
| 1620 | return; |
| 1621 | } |
| 1622 | #endif |
| 1623 | #ifdef HAVE_LINUX_USRREGS |
| 1624 | usr_store_inferior_registers (regno); |
| 1625 | #endif |
| 1626 | } |
| 1627 | |
| 1628 | |
| 1629 | /* Copy LEN bytes from inferior's memory starting at MEMADDR |
| 1630 | to debugger memory starting at MYADDR. */ |
| 1631 | |
| 1632 | static int |
| 1633 | linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len) |
| 1634 | { |
| 1635 | register int i; |
| 1636 | /* Round starting address down to longword boundary. */ |
| 1637 | register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); |
| 1638 | /* Round ending address up; get number of longwords that makes. */ |
| 1639 | register int count |
| 1640 | = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) |
| 1641 | / sizeof (PTRACE_XFER_TYPE); |
| 1642 | /* Allocate buffer of that many longwords. */ |
| 1643 | register PTRACE_XFER_TYPE *buffer |
| 1644 | = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); |
| 1645 | int fd; |
| 1646 | char filename[64]; |
| 1647 | |
| 1648 | /* Try using /proc. Don't bother for one word. */ |
| 1649 | if (len >= 3 * sizeof (long)) |
| 1650 | { |
| 1651 | /* We could keep this file open and cache it - possibly one per |
| 1652 | thread. That requires some juggling, but is even faster. */ |
| 1653 | sprintf (filename, "/proc/%ld/mem", inferior_pid); |
| 1654 | fd = open (filename, O_RDONLY | O_LARGEFILE); |
| 1655 | if (fd == -1) |
| 1656 | goto no_proc; |
| 1657 | |
| 1658 | /* If pread64 is available, use it. It's faster if the kernel |
| 1659 | supports it (only one syscall), and it's 64-bit safe even on |
| 1660 | 32-bit platforms (for instance, SPARC debugging a SPARC64 |
| 1661 | application). */ |
| 1662 | #ifdef HAVE_PREAD64 |
| 1663 | if (pread64 (fd, myaddr, len, memaddr) != len) |
| 1664 | #else |
| 1665 | if (lseek (fd, memaddr, SEEK_SET) == -1 || read (fd, memaddr, len) != len) |
| 1666 | #endif |
| 1667 | { |
| 1668 | close (fd); |
| 1669 | goto no_proc; |
| 1670 | } |
| 1671 | |
| 1672 | close (fd); |
| 1673 | return 0; |
| 1674 | } |
| 1675 | |
| 1676 | no_proc: |
| 1677 | /* Read all the longwords */ |
| 1678 | for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) |
| 1679 | { |
| 1680 | errno = 0; |
| 1681 | buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0); |
| 1682 | if (errno) |
| 1683 | return errno; |
| 1684 | } |
| 1685 | |
| 1686 | /* Copy appropriate bytes out of the buffer. */ |
| 1687 | memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len); |
| 1688 | |
| 1689 | return 0; |
| 1690 | } |
| 1691 | |
| 1692 | /* Copy LEN bytes of data from debugger memory at MYADDR |
| 1693 | to inferior's memory at MEMADDR. |
| 1694 | On failure (cannot write the inferior) |
| 1695 | returns the value of errno. */ |
| 1696 | |
| 1697 | static int |
| 1698 | linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len) |
| 1699 | { |
| 1700 | register int i; |
| 1701 | /* Round starting address down to longword boundary. */ |
| 1702 | register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); |
| 1703 | /* Round ending address up; get number of longwords that makes. */ |
| 1704 | register int count |
| 1705 | = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE); |
| 1706 | /* Allocate buffer of that many longwords. */ |
| 1707 | register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); |
| 1708 | extern int errno; |
| 1709 | |
| 1710 | if (debug_threads) |
| 1711 | { |
| 1712 | fprintf (stderr, "Writing %02x to %08lx\n", (unsigned)myaddr[0], (long)memaddr); |
| 1713 | } |
| 1714 | |
| 1715 | /* Fill start and end extra bytes of buffer with existing memory data. */ |
| 1716 | |
| 1717 | buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid, |
| 1718 | (PTRACE_ARG3_TYPE) addr, 0); |
| 1719 | |
| 1720 | if (count > 1) |
| 1721 | { |
| 1722 | buffer[count - 1] |
| 1723 | = ptrace (PTRACE_PEEKTEXT, inferior_pid, |
| 1724 | (PTRACE_ARG3_TYPE) (addr + (count - 1) |
| 1725 | * sizeof (PTRACE_XFER_TYPE)), |
| 1726 | 0); |
| 1727 | } |
| 1728 | |
| 1729 | /* Copy data to be written over corresponding part of buffer */ |
| 1730 | |
| 1731 | memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), myaddr, len); |
| 1732 | |
| 1733 | /* Write the entire buffer. */ |
| 1734 | |
| 1735 | for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) |
| 1736 | { |
| 1737 | errno = 0; |
| 1738 | ptrace (PTRACE_POKETEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, buffer[i]); |
| 1739 | if (errno) |
| 1740 | return errno; |
| 1741 | } |
| 1742 | |
| 1743 | return 0; |
| 1744 | } |
| 1745 | |
| 1746 | static int linux_supports_tracefork_flag; |
| 1747 | |
| 1748 | /* Helper functions for linux_test_for_tracefork, called via clone (). */ |
| 1749 | |
| 1750 | static int |
| 1751 | linux_tracefork_grandchild (void *arg) |
| 1752 | { |
| 1753 | _exit (0); |
| 1754 | } |
| 1755 | |
| 1756 | #define STACK_SIZE 4096 |
| 1757 | |
| 1758 | static int |
| 1759 | linux_tracefork_child (void *arg) |
| 1760 | { |
| 1761 | ptrace (PTRACE_TRACEME, 0, 0, 0); |
| 1762 | kill (getpid (), SIGSTOP); |
| 1763 | #ifdef __ia64__ |
| 1764 | __clone2 (linux_tracefork_grandchild, arg, STACK_SIZE, |
| 1765 | CLONE_VM | SIGCHLD, NULL); |
| 1766 | #else |
| 1767 | clone (linux_tracefork_grandchild, arg + STACK_SIZE, |
| 1768 | CLONE_VM | SIGCHLD, NULL); |
| 1769 | #endif |
| 1770 | _exit (0); |
| 1771 | } |
| 1772 | |
| 1773 | /* Wrapper function for waitpid which handles EINTR. */ |
| 1774 | |
| 1775 | static int |
| 1776 | my_waitpid (int pid, int *status, int flags) |
| 1777 | { |
| 1778 | int ret; |
| 1779 | do |
| 1780 | { |
| 1781 | ret = waitpid (pid, status, flags); |
| 1782 | } |
| 1783 | while (ret == -1 && errno == EINTR); |
| 1784 | |
| 1785 | return ret; |
| 1786 | } |
| 1787 | |
| 1788 | /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. Make |
| 1789 | sure that we can enable the option, and that it had the desired |
| 1790 | effect. */ |
| 1791 | |
| 1792 | static void |
| 1793 | linux_test_for_tracefork (void) |
| 1794 | { |
| 1795 | int child_pid, ret, status; |
| 1796 | long second_pid; |
| 1797 | char *stack = malloc (STACK_SIZE * 4); |
| 1798 | |
| 1799 | linux_supports_tracefork_flag = 0; |
| 1800 | |
| 1801 | /* Use CLONE_VM instead of fork, to support uClinux (no MMU). */ |
| 1802 | #ifdef __ia64__ |
| 1803 | child_pid = __clone2 (linux_tracefork_child, stack, STACK_SIZE, |
| 1804 | CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2); |
| 1805 | #else |
| 1806 | child_pid = clone (linux_tracefork_child, stack + STACK_SIZE, |
| 1807 | CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2); |
| 1808 | #endif |
| 1809 | if (child_pid == -1) |
| 1810 | perror_with_name ("clone"); |
| 1811 | |
| 1812 | ret = my_waitpid (child_pid, &status, 0); |
| 1813 | if (ret == -1) |
| 1814 | perror_with_name ("waitpid"); |
| 1815 | else if (ret != child_pid) |
| 1816 | error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret); |
| 1817 | if (! WIFSTOPPED (status)) |
| 1818 | error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status); |
| 1819 | |
| 1820 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK); |
| 1821 | if (ret != 0) |
| 1822 | { |
| 1823 | ret = ptrace (PTRACE_KILL, child_pid, 0, 0); |
| 1824 | if (ret != 0) |
| 1825 | { |
| 1826 | warning ("linux_test_for_tracefork: failed to kill child"); |
| 1827 | return; |
| 1828 | } |
| 1829 | |
| 1830 | ret = my_waitpid (child_pid, &status, 0); |
| 1831 | if (ret != child_pid) |
| 1832 | warning ("linux_test_for_tracefork: failed to wait for killed child"); |
| 1833 | else if (!WIFSIGNALED (status)) |
| 1834 | warning ("linux_test_for_tracefork: unexpected wait status 0x%x from " |
| 1835 | "killed child", status); |
| 1836 | |
| 1837 | return; |
| 1838 | } |
| 1839 | |
| 1840 | ret = ptrace (PTRACE_CONT, child_pid, 0, 0); |
| 1841 | if (ret != 0) |
| 1842 | warning ("linux_test_for_tracefork: failed to resume child"); |
| 1843 | |
| 1844 | ret = my_waitpid (child_pid, &status, 0); |
| 1845 | |
| 1846 | if (ret == child_pid && WIFSTOPPED (status) |
| 1847 | && status >> 16 == PTRACE_EVENT_FORK) |
| 1848 | { |
| 1849 | second_pid = 0; |
| 1850 | ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid); |
| 1851 | if (ret == 0 && second_pid != 0) |
| 1852 | { |
| 1853 | int second_status; |
| 1854 | |
| 1855 | linux_supports_tracefork_flag = 1; |
| 1856 | my_waitpid (second_pid, &second_status, 0); |
| 1857 | ret = ptrace (PTRACE_KILL, second_pid, 0, 0); |
| 1858 | if (ret != 0) |
| 1859 | warning ("linux_test_for_tracefork: failed to kill second child"); |
| 1860 | my_waitpid (second_pid, &status, 0); |
| 1861 | } |
| 1862 | } |
| 1863 | else |
| 1864 | warning ("linux_test_for_tracefork: unexpected result from waitpid " |
| 1865 | "(%d, status 0x%x)", ret, status); |
| 1866 | |
| 1867 | do |
| 1868 | { |
| 1869 | ret = ptrace (PTRACE_KILL, child_pid, 0, 0); |
| 1870 | if (ret != 0) |
| 1871 | warning ("linux_test_for_tracefork: failed to kill child"); |
| 1872 | my_waitpid (child_pid, &status, 0); |
| 1873 | } |
| 1874 | while (WIFSTOPPED (status)); |
| 1875 | |
| 1876 | free (stack); |
| 1877 | } |
| 1878 | |
| 1879 | |
| 1880 | static void |
| 1881 | linux_look_up_symbols (void) |
| 1882 | { |
| 1883 | #ifdef USE_THREAD_DB |
| 1884 | if (thread_db_active) |
| 1885 | return; |
| 1886 | |
| 1887 | thread_db_active = thread_db_init (!linux_supports_tracefork_flag); |
| 1888 | #endif |
| 1889 | } |
| 1890 | |
| 1891 | static void |
| 1892 | linux_request_interrupt (void) |
| 1893 | { |
| 1894 | extern unsigned long signal_pid; |
| 1895 | |
| 1896 | if (cont_thread != 0 && cont_thread != -1) |
| 1897 | { |
| 1898 | struct process_info *process; |
| 1899 | |
| 1900 | process = get_thread_process (current_inferior); |
| 1901 | kill_lwp (process->lwpid, SIGINT); |
| 1902 | } |
| 1903 | else |
| 1904 | kill_lwp (signal_pid, SIGINT); |
| 1905 | } |
| 1906 | |
| 1907 | /* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET |
| 1908 | to debugger memory starting at MYADDR. */ |
| 1909 | |
| 1910 | static int |
| 1911 | linux_read_auxv (CORE_ADDR offset, unsigned char *myaddr, unsigned int len) |
| 1912 | { |
| 1913 | char filename[PATH_MAX]; |
| 1914 | int fd, n; |
| 1915 | |
| 1916 | snprintf (filename, sizeof filename, "/proc/%ld/auxv", inferior_pid); |
| 1917 | |
| 1918 | fd = open (filename, O_RDONLY); |
| 1919 | if (fd < 0) |
| 1920 | return -1; |
| 1921 | |
| 1922 | if (offset != (CORE_ADDR) 0 |
| 1923 | && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset) |
| 1924 | n = -1; |
| 1925 | else |
| 1926 | n = read (fd, myaddr, len); |
| 1927 | |
| 1928 | close (fd); |
| 1929 | |
| 1930 | return n; |
| 1931 | } |
| 1932 | |
| 1933 | /* These watchpoint related wrapper functions simply pass on the function call |
| 1934 | if the target has registered a corresponding function. */ |
| 1935 | |
| 1936 | static int |
| 1937 | linux_insert_watchpoint (char type, CORE_ADDR addr, int len) |
| 1938 | { |
| 1939 | if (the_low_target.insert_watchpoint != NULL) |
| 1940 | return the_low_target.insert_watchpoint (type, addr, len); |
| 1941 | else |
| 1942 | /* Unsupported (see target.h). */ |
| 1943 | return 1; |
| 1944 | } |
| 1945 | |
| 1946 | static int |
| 1947 | linux_remove_watchpoint (char type, CORE_ADDR addr, int len) |
| 1948 | { |
| 1949 | if (the_low_target.remove_watchpoint != NULL) |
| 1950 | return the_low_target.remove_watchpoint (type, addr, len); |
| 1951 | else |
| 1952 | /* Unsupported (see target.h). */ |
| 1953 | return 1; |
| 1954 | } |
| 1955 | |
| 1956 | static int |
| 1957 | linux_stopped_by_watchpoint (void) |
| 1958 | { |
| 1959 | if (the_low_target.stopped_by_watchpoint != NULL) |
| 1960 | return the_low_target.stopped_by_watchpoint (); |
| 1961 | else |
| 1962 | return 0; |
| 1963 | } |
| 1964 | |
| 1965 | static CORE_ADDR |
| 1966 | linux_stopped_data_address (void) |
| 1967 | { |
| 1968 | if (the_low_target.stopped_data_address != NULL) |
| 1969 | return the_low_target.stopped_data_address (); |
| 1970 | else |
| 1971 | return 0; |
| 1972 | } |
| 1973 | |
| 1974 | #if defined(__UCLIBC__) && defined(HAS_NOMMU) |
| 1975 | #if defined(__mcoldfire__) |
| 1976 | /* These should really be defined in the kernel's ptrace.h header. */ |
| 1977 | #define PT_TEXT_ADDR 49*4 |
| 1978 | #define PT_DATA_ADDR 50*4 |
| 1979 | #define PT_TEXT_END_ADDR 51*4 |
| 1980 | #endif |
| 1981 | |
| 1982 | /* Under uClinux, programs are loaded at non-zero offsets, which we need |
| 1983 | to tell gdb about. */ |
| 1984 | |
| 1985 | static int |
| 1986 | linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p) |
| 1987 | { |
| 1988 | #if defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) && defined(PT_TEXT_END_ADDR) |
| 1989 | unsigned long text, text_end, data; |
| 1990 | int pid = get_thread_process (current_inferior)->head.id; |
| 1991 | |
| 1992 | errno = 0; |
| 1993 | |
| 1994 | text = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_ADDR, 0); |
| 1995 | text_end = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_END_ADDR, 0); |
| 1996 | data = ptrace (PTRACE_PEEKUSER, pid, (long)PT_DATA_ADDR, 0); |
| 1997 | |
| 1998 | if (errno == 0) |
| 1999 | { |
| 2000 | /* Both text and data offsets produced at compile-time (and so |
| 2001 | used by gdb) are relative to the beginning of the program, |
| 2002 | with the data segment immediately following the text segment. |
| 2003 | However, the actual runtime layout in memory may put the data |
| 2004 | somewhere else, so when we send gdb a data base-address, we |
| 2005 | use the real data base address and subtract the compile-time |
| 2006 | data base-address from it (which is just the length of the |
| 2007 | text segment). BSS immediately follows data in both |
| 2008 | cases. */ |
| 2009 | *text_p = text; |
| 2010 | *data_p = data - (text_end - text); |
| 2011 | |
| 2012 | return 1; |
| 2013 | } |
| 2014 | #endif |
| 2015 | return 0; |
| 2016 | } |
| 2017 | #endif |
| 2018 | |
| 2019 | static const char * |
| 2020 | linux_arch_string (void) |
| 2021 | { |
| 2022 | return the_low_target.arch_string; |
| 2023 | } |
| 2024 | |
| 2025 | static struct target_ops linux_target_ops = { |
| 2026 | linux_create_inferior, |
| 2027 | linux_attach, |
| 2028 | linux_kill, |
| 2029 | linux_detach, |
| 2030 | linux_join, |
| 2031 | linux_thread_alive, |
| 2032 | linux_resume, |
| 2033 | linux_wait, |
| 2034 | linux_fetch_registers, |
| 2035 | linux_store_registers, |
| 2036 | linux_read_memory, |
| 2037 | linux_write_memory, |
| 2038 | linux_look_up_symbols, |
| 2039 | linux_request_interrupt, |
| 2040 | linux_read_auxv, |
| 2041 | linux_insert_watchpoint, |
| 2042 | linux_remove_watchpoint, |
| 2043 | linux_stopped_by_watchpoint, |
| 2044 | linux_stopped_data_address, |
| 2045 | #if defined(__UCLIBC__) && defined(HAS_NOMMU) |
| 2046 | linux_read_offsets, |
| 2047 | #else |
| 2048 | NULL, |
| 2049 | #endif |
| 2050 | #ifdef USE_THREAD_DB |
| 2051 | thread_db_get_tls_address, |
| 2052 | #else |
| 2053 | NULL, |
| 2054 | #endif |
| 2055 | linux_arch_string, |
| 2056 | }; |
| 2057 | |
| 2058 | static void |
| 2059 | linux_init_signals () |
| 2060 | { |
| 2061 | /* FIXME drow/2002-06-09: As above, we should check with LinuxThreads |
| 2062 | to find what the cancel signal actually is. */ |
| 2063 | signal (__SIGRTMIN+1, SIG_IGN); |
| 2064 | } |
| 2065 | |
| 2066 | void |
| 2067 | initialize_low (void) |
| 2068 | { |
| 2069 | thread_db_active = 0; |
| 2070 | set_target_ops (&linux_target_ops); |
| 2071 | set_breakpoint_data (the_low_target.breakpoint, |
| 2072 | the_low_target.breakpoint_len); |
| 2073 | init_registers (); |
| 2074 | linux_init_signals (); |
| 2075 | linux_test_for_tracefork (); |
| 2076 | } |