gdb/inftarg.c

   1 /* Target-vector operations for controlling Unix child processes, for GDB.
   2
   3    Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999,
   4    2000, 2002, 2003, 2004 Free Software Foundation, Inc.
   5
   6    Contributed by Cygnus Support.
   7
   8    ## Contains temporary hacks..
   9
  10    This file is part of GDB.
  11
  12    This program is free software; you can redistribute it and/or modify
  13    it under the terms of the GNU General Public License as published by
  14    the Free Software Foundation; either version 2 of the License, or
  15    (at your option) any later version.
  16
  17    This program is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program; if not, write to the Free Software
  24    Foundation, Inc., 59 Temple Place - Suite 330,
  25    Boston, MA 02111-1307, USA.  */
  26
  27 #include "defs.h"
  28 #include "frame.h"              /* required by inferior.h */
  29 #include "inferior.h"
  30 #include "target.h"
  31 #include "gdbcore.h"
  32 #include "command.h"
  33 #include "gdb_stat.h"
  34 #include <signal.h>
  35 #include <sys/types.h>
  36 #include <fcntl.h>
  37 #include "observer.h"
  38 #include "gdb_wait.h"
  39 #include "inflow.h"
  40
  41 extern struct symtab_and_line *child_enable_exception_callback (enum
  42                                                                 exception_event_kind,
  43                                                                 int);
  44
  45 extern struct exception_event_record
  46   *child_get_current_exception_event (void);
  47
  48 extern void _initialize_inftarg (void);
  49
  50 static void child_prepare_to_store (void);
  51
  52 #ifndef CHILD_WAIT
  53 static ptid_t child_wait (ptid_t, struct target_waitstatus *);
  54 #endif /* CHILD_WAIT */
  55
  56 static void child_open (char *, int);
  57
  58 static void child_files_info (struct target_ops *);
  59
  60 static void child_detach (char *, int);
  61
  62 static void child_attach (char *, int);
  63
  64 #if !defined(CHILD_POST_ATTACH)
  65 extern void child_post_attach (int);
  66 #endif
  67
  68 static void ptrace_me (void);
  69
  70 static void ptrace_him (int);
  71
  72 static void child_create_inferior (char *, char *, char **, int);
  73
  74 static void child_mourn_inferior (void);
  75
  76 static int child_can_run (void);
  77
  78 static void child_stop (void);
  79
  80 #ifndef CHILD_THREAD_ALIVE
  81 int child_thread_alive (ptid_t);
  82 #endif
  83
  84 static void init_child_ops (void);
  85
  86 extern char **environ;
  87
  88 int child_suppress_run = 0;     /* Non-zero if inftarg should pretend not to
  89                                    be a runnable target.  Used by targets
  90                                    that can sit atop inftarg, such as HPUX
  91                                    thread support.  */
  92
  93 #ifndef CHILD_WAIT
  94
  95 /* Wait for child to do something.  Return pid of child, or -1 in case
  96    of error; store status through argument pointer OURSTATUS.  */
  97
  98 static ptid_t
  99 child_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
 100 {
 101   int save_errno;
 102   int status;
 103   char *execd_pathname = NULL;
 104   int exit_status;
 105   int related_pid;
 106   int syscall_id;
 107   enum target_waitkind kind;
 108   int pid;
 109
 110   do
 111     {
 112       set_sigint_trap ();       /* Causes SIGINT to be passed on to the
 113                                    attached process. */
 114       set_sigio_trap ();
 115
 116       pid = wait (&status);
 117
 118       save_errno = errno;
 119
 120       clear_sigio_trap ();
 121
 122       clear_sigint_trap ();
 123
 124       if (pid == -1)
 125         {
 126           if (save_errno == EINTR)
 127             continue;
 128
 129           fprintf_unfiltered (gdb_stderr, "Child process unexpectedly missing: %s.\n",
 130                               safe_strerror (save_errno));
 131
 132           /* Claim it exited with unknown signal.  */
 133           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 134           ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
 135           return pid_to_ptid (-1);
 136         }
 137
 138       /* Did it exit?
 139        */
 140       if (target_has_exited (pid, status, &exit_status))
 141         {
 142           /* ??rehrauer: For now, ignore this. */
 143           continue;
 144         }
 145
 146       if (!target_thread_alive (pid_to_ptid (pid)))
 147         {
 148           ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 149           return pid_to_ptid (pid);
 150         }
 151       } while (pid != PIDGET (inferior_ptid)); /* Some other child died or stopped */
 152
 153   store_waitstatus (ourstatus, status);
 154   return pid_to_ptid (pid);
 155 }
 156 #endif /* CHILD_WAIT */
 157
 158 #ifndef CHILD_THREAD_ALIVE
 159
 160 /* Check to see if the given thread is alive.
 161
 162    FIXME: Is kill() ever the right way to do this?  I doubt it, but
 163    for now we're going to try and be compatable with the old thread
 164    code.  */
 165 int
 166 child_thread_alive (ptid_t ptid)
 167 {
 168   pid_t pid = PIDGET (ptid);
 169
 170   return (kill (pid, 0) != -1);
 171 }
 172
 173 #endif
 174
 175 /* Attach to process PID, then initialize for debugging it.  */
 176
 177 static void
 178 child_attach (char *args, int from_tty)
 179 {
 180   char *exec_file;
 181   int pid;
 182   char *dummy;
 183
 184   if (!args)
 185     error_no_arg ("process-id to attach");
 186
 187   dummy = args;
 188   pid = strtol (args, &dummy, 0);
 189   /* Some targets don't set errno on errors, grrr! */
 190   if ((pid == 0) && (args == dummy))
 191       error (_("Illegal process-id: %s."), args);
 192
 193   if (pid == getpid ()) /* Trying to masturbate? */
 194     error (_("I refuse to debug myself!"));
 195
 196   if (from_tty)
 197     {
 198       exec_file = (char *) get_exec_file (0);
 199
 200       if (exec_file)
 201         printf_unfiltered ("Attaching to program: %s, %s\n", exec_file,
 202                            target_pid_to_str (pid_to_ptid (pid)));
 203       else
 204         printf_unfiltered ("Attaching to %s\n",
 205                            target_pid_to_str (pid_to_ptid (pid)));
 206
 207       gdb_flush (gdb_stdout);
 208     }
 209
 210   attach (pid);
 211
 212   inferior_ptid = pid_to_ptid (pid);
 213   push_target (&deprecated_child_ops);
 214
 215   /* Do this first, before anything has had a chance to query the
 216      inferior's symbol table or similar.  */
 217   observer_notify_inferior_created (&current_target, from_tty);
 218 }
 219
 220 #if !defined(CHILD_POST_ATTACH)
 221 void
 222 child_post_attach (int pid)
 223 {
 224   /* This version of Unix doesn't require a meaningful "post attach"
 225      operation by a debugger.  */
 226 }
 227 #endif
 228
 229 /* Take a program previously attached to and detaches it.
 230    The program resumes execution and will no longer stop
 231    on signals, etc.  We'd better not have left any breakpoints
 232    in the program or it'll die when it hits one.  For this
 233    to work, it may be necessary for the process to have been
 234    previously attached.  It *might* work if the program was
 235    started via the normal ptrace (PTRACE_TRACEME).  */
 236
 237 static void
 238 child_detach (char *args, int from_tty)
 239 {
 240   int siggnal = 0;
 241   int pid = PIDGET (inferior_ptid);
 242
 243   if (from_tty)
 244     {
 245       char *exec_file = get_exec_file (0);
 246       if (exec_file == 0)
 247         exec_file = "";
 248       printf_unfiltered ("Detaching from program: %s, %s\n", exec_file,
 249                          target_pid_to_str (pid_to_ptid (pid)));
 250       gdb_flush (gdb_stdout);
 251     }
 252   if (args)
 253     siggnal = atoi (args);
 254
 255   detach (siggnal);
 256
 257   inferior_ptid = null_ptid;
 258   unpush_target (&deprecated_child_ops);
 259 }
 260
 261 /* Get ready to modify the registers array.  On machines which store
 262    individual registers, this doesn't need to do anything.  On machines
 263    which store all the registers in one fell swoop, this makes sure
 264    that registers contains all the registers from the program being
 265    debugged.  */
 266
 267 static void
 268 child_prepare_to_store (void)
 269 {
 270 #ifdef CHILD_PREPARE_TO_STORE
 271   CHILD_PREPARE_TO_STORE ();
 272 #endif
 273 }
 274
 275 /* Print status information about what we're accessing.  */
 276
 277 static void
 278 child_files_info (struct target_ops *ignore)
 279 {
 280   printf_unfiltered ("\tUsing the running image of %s %s.\n",
 281       attach_flag ? "attached" : "child", target_pid_to_str (inferior_ptid));
 282 }
 283
 284 static void
 285 child_open (char *arg, int from_tty)
 286 {
 287   error (_("Use the \"run\" command to start a Unix child process."));
 288 }
 289
 290 /* Stub function which causes the inferior that runs it, to be ptrace-able
 291    by its parent process.  */
 292
 293 static void
 294 ptrace_me (void)
 295 {
 296   /* "Trace me, Dr. Memory!" */
 297   call_ptrace (0, 0, (PTRACE_TYPE_ARG3) 0, 0);
 298 }
 299
 300 /* Stub function which causes the GDB that runs it, to start ptrace-ing
 301    the child process.  */
 302
 303 static void
 304 ptrace_him (int pid)
 305 {
 306   push_target (&deprecated_child_ops);
 307
 308   /* On some targets, there must be some explicit synchronization
 309      between the parent and child processes after the debugger
 310      forks, and before the child execs the debuggee program.  This
 311      call basically gives permission for the child to exec.
 312    */
 313
 314   target_acknowledge_created_inferior (pid);
 315
 316   /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h,
 317    * and will be 1 or 2 depending on whether we're starting
 318    * without or with a shell.
 319    */
 320   startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
 321
 322   /* On some targets, there must be some explicit actions taken after
 323      the inferior has been started up.
 324    */
 325   target_post_startup_inferior (pid_to_ptid (pid));
 326 }
 327
 328 /* Start an inferior Unix child process and sets inferior_ptid to its pid.
 329    EXEC_FILE is the file to run.
 330    ALLARGS is a string containing the arguments to the program.
 331    ENV is the environment vector to pass.  Errors reported with error().  */
 332
 333 static void
 334 child_create_inferior (char *exec_file, char *allargs, char **env,
 335                        int from_tty)
 336 {
 337   fork_inferior (exec_file, allargs, env, ptrace_me, ptrace_him, NULL, NULL);
 338
 339   /* We are at the first instruction we care about.  */
 340   observer_notify_inferior_created (&current_target, from_tty);
 341   /* Pedal to the metal... */
 342   proceed ((CORE_ADDR) -1, TARGET_SIGNAL_0, 0);
 343 }
 344
 345 #if !defined(CHILD_POST_STARTUP_INFERIOR)
 346 void
 347 child_post_startup_inferior (ptid_t ptid)
 348 {
 349   /* This version of Unix doesn't require a meaningful "post startup inferior"
 350      operation by a debugger.
 351    */
 352 }
 353 #endif
 354
 355 #if !defined(CHILD_ACKNOWLEDGE_CREATED_INFERIOR)
 356 void
 357 child_acknowledge_created_inferior (int pid)
 358 {
 359   /* This version of Unix doesn't require a meaningful "acknowledge created inferior"
 360      operation by a debugger.
 361    */
 362 }
 363 #endif
 364
 365
 366 #if !defined(CHILD_INSERT_FORK_CATCHPOINT)
 367 void
 368 child_insert_fork_catchpoint (int pid)
 369 {
 370   /* This version of Unix doesn't support notification of fork
 371      events.  */
 372 }
 373 #endif
 374
 375 #if !defined(CHILD_REMOVE_FORK_CATCHPOINT)
 376 int
 377 child_remove_fork_catchpoint (int pid)
 378 {
 379   /* This version of Unix doesn't support notification of fork events.  */
 380   return 0;
 381 }
 382 #endif
 383
 384 #if !defined(CHILD_INSERT_VFORK_CATCHPOINT)
 385 void
 386 child_insert_vfork_catchpoint (int pid)
 387 {
 388   /* This version of Unix doesn't support notification of vfork
 389      events.  */
 390 }
 391 #endif
 392
 393 #if !defined(CHILD_REMOVE_VFORK_CATCHPOINT)
 394 int
 395 child_remove_vfork_catchpoint (int pid)
 396 {
 397   /* This version of Unix doesn't support notification of vfork events.  */
 398   return 0;
 399 }
 400 #endif
 401
 402 #if !defined(CHILD_FOLLOW_FORK)
 403 int
 404 child_follow_fork (int follow_child)
 405 {
 406   /* This version of Unix doesn't support following fork or vfork events.  */
 407   return 0;
 408 }
 409 #endif
 410
 411 #if !defined(CHILD_INSERT_EXEC_CATCHPOINT)
 412 void
 413 child_insert_exec_catchpoint (int pid)
 414 {
 415   /* This version of Unix doesn't support notification of exec
 416      events.  */
 417 }
 418 #endif
 419
 420 #if !defined(CHILD_REMOVE_EXEC_CATCHPOINT)
 421 int
 422 child_remove_exec_catchpoint (int pid)
 423 {
 424   /* This version of Unix doesn't support notification of exec events.  */
 425   return 0;
 426 }
 427 #endif
 428
 429 #if !defined(CHILD_REPORTED_EXEC_EVENTS_PER_EXEC_CALL)
 430 int
 431 child_reported_exec_events_per_exec_call (void)
 432 {
 433   /* This version of Unix doesn't support notification of exec events.
 434    */
 435   return 1;
 436 }
 437 #endif
 438
 439 #if !defined(CHILD_HAS_EXITED)
 440 int
 441 child_has_exited (int pid, int wait_status, int *exit_status)
 442 {
 443   if (WIFEXITED (wait_status))
 444     {
 445       *exit_status = WEXITSTATUS (wait_status);
 446       return 1;
 447     }
 448
 449   if (WIFSIGNALED (wait_status))
 450     {
 451       *exit_status = 0;         /* ?? Don't know what else to say here. */
 452       return 1;
 453     }
 454
 455   /* ?? Do we really need to consult the event state, too?  Assume the
 456      wait_state alone suffices.
 457    */
 458   return 0;
 459 }
 460 #endif
 461
 462
 463 static void
 464 child_mourn_inferior (void)
 465 {
 466   unpush_target (&deprecated_child_ops);
 467   generic_mourn_inferior ();
 468 }
 469
 470 static int
 471 child_can_run (void)
 472 {
 473   /* This variable is controlled by modules that sit atop inftarg that may layer
 474      their own process structure atop that provided here.  hpux-thread.c does
 475      this because of the Hpux user-mode level thread model.  */
 476
 477   return !child_suppress_run;
 478 }
 479
 480 /* Send a SIGINT to the process group.  This acts just like the user typed a
 481    ^C on the controlling terminal.
 482
 483    XXX - This may not be correct for all systems.  Some may want to use
 484    killpg() instead of kill (-pgrp). */
 485
 486 static void
 487 child_stop (void)
 488 {
 489   kill (-inferior_process_group, SIGINT);
 490 }
 491
 492 #if !defined(CHILD_ENABLE_EXCEPTION_CALLBACK)
 493 struct symtab_and_line *
 494 child_enable_exception_callback (enum exception_event_kind kind, int enable)
 495 {
 496   return (struct symtab_and_line *) NULL;
 497 }
 498 #endif
 499
 500 #if !defined(CHILD_GET_CURRENT_EXCEPTION_EVENT)
 501 struct exception_event_record *
 502 child_get_current_exception_event (void)
 503 {
 504   return (struct exception_event_record *) NULL;
 505 }
 506 #endif
 507
 508
 509 #if !defined(CHILD_PID_TO_EXEC_FILE)
 510 char *
 511 child_pid_to_exec_file (int pid)
 512 {
 513   /* This version of Unix doesn't support translation of a process ID
 514      to the filename of the executable file.
 515    */
 516   return NULL;
 517 }
 518 #endif
 519
 520 char *
 521 child_core_file_to_sym_file (char *core)
 522 {
 523   /* The target stratum for a running executable need not support
 524      this operation.
 525    */
 526   return NULL;
 527 }
 528
 529 /* Perform a partial transfer to/from the specified object.  For
 530    memory transfers, fall back to the old memory xfer functions.  */
 531
 532 static LONGEST
 533 child_xfer_partial (struct target_ops *ops, enum target_object object,
 534                     const char *annex, void *readbuf,
 535                     const void *writebuf, ULONGEST offset, LONGEST len)
 536 {
 537   switch (object)
 538     {
 539     case TARGET_OBJECT_MEMORY:
 540       if (readbuf)
 541         return child_xfer_memory (offset, readbuf, len, 0/*write*/,
 542                                   NULL, ops);
 543       if (writebuf)
 544         return child_xfer_memory (offset, (void *) writebuf, len, 1/*write*/,
 545                                   NULL, ops);
 546       return -1;
 547
 548     case TARGET_OBJECT_UNWIND_TABLE:
 549 #ifndef NATIVE_XFER_UNWIND_TABLE
 550 #define NATIVE_XFER_UNWIND_TABLE(OPS,OBJECT,ANNEX,WRITEBUF,READBUF,OFFSET,LEN) (-1)
 551 #endif
 552       return NATIVE_XFER_UNWIND_TABLE (ops, object, annex, readbuf, writebuf,
 553                                        offset, len);
 554
 555     case TARGET_OBJECT_AUXV:
 556 #ifndef NATIVE_XFER_AUXV
 557 #define NATIVE_XFER_AUXV(OPS,OBJECT,ANNEX,WRITEBUF,READBUF,OFFSET,LEN) (-1)
 558 #endif
 559       return NATIVE_XFER_AUXV (ops, object, annex, readbuf, writebuf,
 560                                offset, len);
 561
 562     default:
 563       return -1;
 564     }
 565 }
 566
 567 #if !defined(CHILD_PID_TO_STR)
 568 char *
 569 child_pid_to_str (ptid_t ptid)
 570 {
 571   return normal_pid_to_str (ptid);
 572 }
 573 #endif
 574
 575 static void
 576 init_child_ops (void)
 577 {
 578   deprecated_child_ops.to_shortname = "child";
 579   deprecated_child_ops.to_longname = "Unix child process";
 580   deprecated_child_ops.to_doc = "Unix child process (started by the \"run\" command).";
 581   deprecated_child_ops.to_open = child_open;
 582   deprecated_child_ops.to_attach = child_attach;
 583   deprecated_child_ops.to_post_attach = child_post_attach;
 584   deprecated_child_ops.to_detach = child_detach;
 585   deprecated_child_ops.to_resume = child_resume;
 586   deprecated_child_ops.to_wait = child_wait;
 587   deprecated_child_ops.to_fetch_registers = fetch_inferior_registers;
 588   deprecated_child_ops.to_store_registers = store_inferior_registers;
 589   deprecated_child_ops.to_prepare_to_store = child_prepare_to_store;
 590   deprecated_child_ops.deprecated_xfer_memory = child_xfer_memory;
 591   deprecated_child_ops.to_xfer_partial = child_xfer_partial;
 592   deprecated_child_ops.to_files_info = child_files_info;
 593   deprecated_child_ops.to_insert_breakpoint = memory_insert_breakpoint;
 594   deprecated_child_ops.to_remove_breakpoint = memory_remove_breakpoint;
 595   deprecated_child_ops.to_terminal_init = terminal_init_inferior;
 596   deprecated_child_ops.to_terminal_inferior = terminal_inferior;
 597   deprecated_child_ops.to_terminal_ours_for_output = terminal_ours_for_output;
 598   deprecated_child_ops.to_terminal_save_ours = terminal_save_ours;
 599   deprecated_child_ops.to_terminal_ours = terminal_ours;
 600   deprecated_child_ops.to_terminal_info = child_terminal_info;
 601   deprecated_child_ops.to_kill = kill_inferior;
 602   deprecated_child_ops.to_create_inferior = child_create_inferior;
 603   deprecated_child_ops.to_post_startup_inferior = child_post_startup_inferior;
 604   deprecated_child_ops.to_acknowledge_created_inferior = child_acknowledge_created_inferior;
 605   deprecated_child_ops.to_insert_fork_catchpoint = child_insert_fork_catchpoint;
 606   deprecated_child_ops.to_remove_fork_catchpoint = child_remove_fork_catchpoint;
 607   deprecated_child_ops.to_insert_vfork_catchpoint = child_insert_vfork_catchpoint;
 608   deprecated_child_ops.to_remove_vfork_catchpoint = child_remove_vfork_catchpoint;
 609   deprecated_child_ops.to_follow_fork = child_follow_fork;
 610   deprecated_child_ops.to_insert_exec_catchpoint = child_insert_exec_catchpoint;
 611   deprecated_child_ops.to_remove_exec_catchpoint = child_remove_exec_catchpoint;
 612   deprecated_child_ops.to_reported_exec_events_per_exec_call = child_reported_exec_events_per_exec_call;
 613   deprecated_child_ops.to_has_exited = child_has_exited;
 614   deprecated_child_ops.to_mourn_inferior = child_mourn_inferior;
 615   deprecated_child_ops.to_can_run = child_can_run;
 616   deprecated_child_ops.to_thread_alive = child_thread_alive;
 617   deprecated_child_ops.to_pid_to_str = child_pid_to_str;
 618   deprecated_child_ops.to_stop = child_stop;
 619   deprecated_child_ops.to_enable_exception_callback = child_enable_exception_callback;
 620   deprecated_child_ops.to_get_current_exception_event = child_get_current_exception_event;
 621   deprecated_child_ops.to_pid_to_exec_file = child_pid_to_exec_file;
 622   deprecated_child_ops.to_stratum = process_stratum;
 623   deprecated_child_ops.to_has_all_memory = 1;
 624   deprecated_child_ops.to_has_memory = 1;
 625   deprecated_child_ops.to_has_stack = 1;
 626   deprecated_child_ops.to_has_registers = 1;
 627   deprecated_child_ops.to_has_execution = 1;
 628   deprecated_child_ops.to_magic = OPS_MAGIC;
 629 }
 630
 631 void
 632 _initialize_inftarg (void)
 633 {
 634 #ifdef HAVE_OPTIONAL_PROC_FS
 635   char procname[32];
 636   int fd;
 637
 638   /* If we have an optional /proc filesystem (e.g. under OSF/1),
 639      don't add ptrace support if we can access the running GDB via /proc.  */
 640 #ifndef PROC_NAME_FMT
 641 #define PROC_NAME_FMT "/proc/%05d"
 642 #endif
 643   sprintf (procname, PROC_NAME_FMT, getpid ());
 644   fd = open (procname, O_RDONLY);
 645   if (fd >= 0)
 646     {
 647       close (fd);
 648       return;
 649     }
 650 #endif
 651
 652   init_child_ops ();
 653   add_target (&deprecated_child_ops);
 654 }