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 #if !defined(CHILD_POST_WAIT)
  57 void child_post_wait (ptid_t, int);
  58 #endif
  59
  60 static void child_open (char *, int);
  61
  62 static void child_files_info (struct target_ops *);
  63
  64 static void child_detach (char *, int);
  65
  66 static void child_attach (char *, int);
  67
  68 #if !defined(CHILD_POST_ATTACH)
  69 extern void child_post_attach (int);
  70 #endif
  71
  72 static void ptrace_me (void);
  73
  74 static void ptrace_him (int);
  75
  76 static void child_create_inferior (char *, char *, char **, int);
  77
  78 static void child_mourn_inferior (void);
  79
  80 static int child_can_run (void);
  81
  82 static void child_stop (void);
  83
  84 #ifndef CHILD_THREAD_ALIVE
  85 int child_thread_alive (ptid_t);
  86 #endif
  87
  88 static void init_child_ops (void);
  89
  90 extern char **environ;
  91
  92 struct target_ops child_ops;
  93
  94 int child_suppress_run = 0;     /* Non-zero if inftarg should pretend not to
  95                                    be a runnable target.  Used by targets
  96                                    that can sit atop inftarg, such as HPUX
  97                                    thread support.  */
  98
  99 #ifndef CHILD_WAIT
 100
 101 /* Wait for child to do something.  Return pid of child, or -1 in case
 102    of error; store status through argument pointer OURSTATUS.  */
 103
 104 static ptid_t
 105 child_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
 106 {
 107   int save_errno;
 108   int status;
 109   char *execd_pathname = NULL;
 110   int exit_status;
 111   int related_pid;
 112   int syscall_id;
 113   enum target_waitkind kind;
 114   int pid;
 115
 116   do
 117     {
 118       set_sigint_trap ();       /* Causes SIGINT to be passed on to the
 119                                    attached process. */
 120       set_sigio_trap ();
 121
 122       pid = ptrace_wait (inferior_ptid, &status);
 123
 124       save_errno = errno;
 125
 126       clear_sigio_trap ();
 127
 128       clear_sigint_trap ();
 129
 130       if (pid == -1)
 131         {
 132           if (save_errno == EINTR)
 133             continue;
 134
 135           fprintf_unfiltered (gdb_stderr, "Child process unexpectedly missing: %s.\n",
 136                               safe_strerror (save_errno));
 137
 138           /* Claim it exited with unknown signal.  */
 139           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 140           ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
 141           return pid_to_ptid (-1);
 142         }
 143
 144       /* Did it exit?
 145        */
 146       if (target_has_exited (pid, status, &exit_status))
 147         {
 148           /* ??rehrauer: For now, ignore this. */
 149           continue;
 150         }
 151
 152       if (!target_thread_alive (pid_to_ptid (pid)))
 153         {
 154           ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 155           return pid_to_ptid (pid);
 156         }
 157       } while (pid != PIDGET (inferior_ptid)); /* Some other child died or stopped */
 158
 159   store_waitstatus (ourstatus, status);
 160   return pid_to_ptid (pid);
 161 }
 162 #endif /* CHILD_WAIT */
 163
 164 #if !defined(CHILD_POST_WAIT)
 165 void
 166 child_post_wait (ptid_t ptid, int wait_status)
 167 {
 168   /* This version of Unix doesn't require a meaningful "post wait"
 169      operation.
 170    */
 171 }
 172 #endif
 173
 174
 175 #ifndef CHILD_THREAD_ALIVE
 176
 177 /* Check to see if the given thread is alive.
 178
 179    FIXME: Is kill() ever the right way to do this?  I doubt it, but
 180    for now we're going to try and be compatable with the old thread
 181    code.  */
 182 int
 183 child_thread_alive (ptid_t ptid)
 184 {
 185   pid_t pid = PIDGET (ptid);
 186
 187   return (kill (pid, 0) != -1);
 188 }
 189
 190 #endif
 191
 192 /* Attach to process PID, then initialize for debugging it.  */
 193
 194 static void
 195 child_attach (char *args, int from_tty)
 196 {
 197   char *exec_file;
 198   int pid;
 199   char *dummy;
 200
 201   if (!args)
 202     error_no_arg ("process-id to attach");
 203
 204   dummy = args;
 205   pid = strtol (args, &dummy, 0);
 206   /* Some targets don't set errno on errors, grrr! */
 207   if ((pid == 0) && (args == dummy))
 208       error ("Illegal process-id: %s\n", args);
 209
 210   if (pid == getpid ()) /* Trying to masturbate? */
 211     error ("I refuse to debug myself!");
 212
 213   if (from_tty)
 214     {
 215       exec_file = (char *) get_exec_file (0);
 216
 217       if (exec_file)
 218         printf_unfiltered ("Attaching to program: %s, %s\n", exec_file,
 219                            target_pid_to_str (pid_to_ptid (pid)));
 220       else
 221         printf_unfiltered ("Attaching to %s\n",
 222                            target_pid_to_str (pid_to_ptid (pid)));
 223
 224       gdb_flush (gdb_stdout);
 225     }
 226
 227   attach (pid);
 228
 229   inferior_ptid = pid_to_ptid (pid);
 230   push_target (&child_ops);
 231 }
 232
 233 #if !defined(CHILD_POST_ATTACH)
 234 void
 235 child_post_attach (int pid)
 236 {
 237   /* This version of Unix doesn't require a meaningful "post attach"
 238      operation by a debugger.  */
 239 }
 240 #endif
 241
 242 /* Take a program previously attached to and detaches it.
 243    The program resumes execution and will no longer stop
 244    on signals, etc.  We'd better not have left any breakpoints
 245    in the program or it'll die when it hits one.  For this
 246    to work, it may be necessary for the process to have been
 247    previously attached.  It *might* work if the program was
 248    started via the normal ptrace (PTRACE_TRACEME).  */
 249
 250 static void
 251 child_detach (char *args, int from_tty)
 252 {
 253   int siggnal = 0;
 254   int pid = PIDGET (inferior_ptid);
 255
 256   if (from_tty)
 257     {
 258       char *exec_file = get_exec_file (0);
 259       if (exec_file == 0)
 260         exec_file = "";
 261       printf_unfiltered ("Detaching from program: %s, %s\n", exec_file,
 262                          target_pid_to_str (pid_to_ptid (pid)));
 263       gdb_flush (gdb_stdout);
 264     }
 265   if (args)
 266     siggnal = atoi (args);
 267
 268   detach (siggnal);
 269
 270   inferior_ptid = null_ptid;
 271   unpush_target (&child_ops);
 272 }
 273
 274 /* Get ready to modify the registers array.  On machines which store
 275    individual registers, this doesn't need to do anything.  On machines
 276    which store all the registers in one fell swoop, this makes sure
 277    that registers contains all the registers from the program being
 278    debugged.  */
 279
 280 static void
 281 child_prepare_to_store (void)
 282 {
 283 #ifdef CHILD_PREPARE_TO_STORE
 284   CHILD_PREPARE_TO_STORE ();
 285 #endif
 286 }
 287
 288 /* Print status information about what we're accessing.  */
 289
 290 static void
 291 child_files_info (struct target_ops *ignore)
 292 {
 293   printf_unfiltered ("\tUsing the running image of %s %s.\n",
 294       attach_flag ? "attached" : "child", target_pid_to_str (inferior_ptid));
 295 }
 296
 297 static void
 298 child_open (char *arg, int from_tty)
 299 {
 300   error ("Use the \"run\" command to start a Unix child process.");
 301 }
 302
 303 /* Stub function which causes the inferior that runs it, to be ptrace-able
 304    by its parent process.  */
 305
 306 static void
 307 ptrace_me (void)
 308 {
 309   /* "Trace me, Dr. Memory!" */
 310   call_ptrace (0, 0, (PTRACE_ARG3_TYPE) 0, 0);
 311 }
 312
 313 /* Stub function which causes the GDB that runs it, to start ptrace-ing
 314    the child process.  */
 315
 316 static void
 317 ptrace_him (int pid)
 318 {
 319   push_target (&child_ops);
 320
 321   /* On some targets, there must be some explicit synchronization
 322      between the parent and child processes after the debugger
 323      forks, and before the child execs the debuggee program.  This
 324      call basically gives permission for the child to exec.
 325    */
 326
 327   target_acknowledge_created_inferior (pid);
 328
 329   /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h,
 330    * and will be 1 or 2 depending on whether we're starting
 331    * without or with a shell.
 332    */
 333   startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
 334
 335   /* On some targets, there must be some explicit actions taken after
 336      the inferior has been started up.
 337    */
 338   target_post_startup_inferior (pid_to_ptid (pid));
 339 }
 340
 341 /* Start an inferior Unix child process and sets inferior_ptid to its pid.
 342    EXEC_FILE is the file to run.
 343    ALLARGS is a string containing the arguments to the program.
 344    ENV is the environment vector to pass.  Errors reported with error().  */
 345
 346 static void
 347 child_create_inferior (char *exec_file, char *allargs, char **env,
 348                        int from_tty)
 349 {
 350 #ifdef HPUXHPPA
 351   fork_inferior (exec_file, allargs, env, ptrace_me, ptrace_him, pre_fork_inferior, NULL);
 352 #else
 353   fork_inferior (exec_file, allargs, env, ptrace_me, ptrace_him, NULL, NULL);
 354 #endif
 355   /* We are at the first instruction we care about.  */
 356   observer_notify_inferior_created (&current_target, from_tty);
 357   /* Pedal to the metal... */
 358   proceed ((CORE_ADDR) -1, TARGET_SIGNAL_0, 0);
 359 }
 360
 361 #if !defined(CHILD_POST_STARTUP_INFERIOR)
 362 void
 363 child_post_startup_inferior (ptid_t ptid)
 364 {
 365   /* This version of Unix doesn't require a meaningful "post startup inferior"
 366      operation by a debugger.
 367    */
 368 }
 369 #endif
 370
 371 #if !defined(CHILD_ACKNOWLEDGE_CREATED_INFERIOR)
 372 void
 373 child_acknowledge_created_inferior (int pid)
 374 {
 375   /* This version of Unix doesn't require a meaningful "acknowledge created inferior"
 376      operation by a debugger.
 377    */
 378 }
 379 #endif
 380
 381
 382 #if !defined(CHILD_INSERT_FORK_CATCHPOINT)
 383 int
 384 child_insert_fork_catchpoint (int pid)
 385 {
 386   /* This version of Unix doesn't support notification of fork events.  */
 387   return 0;
 388 }
 389 #endif
 390
 391 #if !defined(CHILD_REMOVE_FORK_CATCHPOINT)
 392 int
 393 child_remove_fork_catchpoint (int pid)
 394 {
 395   /* This version of Unix doesn't support notification of fork events.  */
 396   return 0;
 397 }
 398 #endif
 399
 400 #if !defined(CHILD_INSERT_VFORK_CATCHPOINT)
 401 int
 402 child_insert_vfork_catchpoint (int pid)
 403 {
 404   /* This version of Unix doesn't support notification of vfork events.  */
 405   return 0;
 406 }
 407 #endif
 408
 409 #if !defined(CHILD_REMOVE_VFORK_CATCHPOINT)
 410 int
 411 child_remove_vfork_catchpoint (int pid)
 412 {
 413   /* This version of Unix doesn't support notification of vfork events.  */
 414   return 0;
 415 }
 416 #endif
 417
 418 #if !defined(CHILD_FOLLOW_FORK)
 419 int
 420 child_follow_fork (int follow_child)
 421 {
 422   /* This version of Unix doesn't support following fork or vfork events.  */
 423   return 0;
 424 }
 425 #endif
 426
 427 #if !defined(CHILD_INSERT_EXEC_CATCHPOINT)
 428 int
 429 child_insert_exec_catchpoint (int pid)
 430 {
 431   /* This version of Unix doesn't support notification of exec events.  */
 432   return 0;
 433 }
 434 #endif
 435
 436 #if !defined(CHILD_REMOVE_EXEC_CATCHPOINT)
 437 int
 438 child_remove_exec_catchpoint (int pid)
 439 {
 440   /* This version of Unix doesn't support notification of exec events.  */
 441   return 0;
 442 }
 443 #endif
 444
 445 #if !defined(CHILD_REPORTED_EXEC_EVENTS_PER_EXEC_CALL)
 446 int
 447 child_reported_exec_events_per_exec_call (void)
 448 {
 449   /* This version of Unix doesn't support notification of exec events.
 450    */
 451   return 1;
 452 }
 453 #endif
 454
 455 #if !defined(CHILD_HAS_EXITED)
 456 int
 457 child_has_exited (int pid, int wait_status, int *exit_status)
 458 {
 459   if (WIFEXITED (wait_status))
 460     {
 461       *exit_status = WEXITSTATUS (wait_status);
 462       return 1;
 463     }
 464
 465   if (WIFSIGNALED (wait_status))
 466     {
 467       *exit_status = 0;         /* ?? Don't know what else to say here. */
 468       return 1;
 469     }
 470
 471   /* ?? Do we really need to consult the event state, too?  Assume the
 472      wait_state alone suffices.
 473    */
 474   return 0;
 475 }
 476 #endif
 477
 478
 479 static void
 480 child_mourn_inferior (void)
 481 {
 482   unpush_target (&child_ops);
 483   generic_mourn_inferior ();
 484 }
 485
 486 static int
 487 child_can_run (void)
 488 {
 489   /* This variable is controlled by modules that sit atop inftarg that may layer
 490      their own process structure atop that provided here.  hpux-thread.c does
 491      this because of the Hpux user-mode level thread model.  */
 492
 493   return !child_suppress_run;
 494 }
 495
 496 /* Send a SIGINT to the process group.  This acts just like the user typed a
 497    ^C on the controlling terminal.
 498
 499    XXX - This may not be correct for all systems.  Some may want to use
 500    killpg() instead of kill (-pgrp). */
 501
 502 static void
 503 child_stop (void)
 504 {
 505   kill (-inferior_process_group, SIGINT);
 506 }
 507
 508 #if !defined(CHILD_ENABLE_EXCEPTION_CALLBACK)
 509 struct symtab_and_line *
 510 child_enable_exception_callback (enum exception_event_kind kind, int enable)
 511 {
 512   return (struct symtab_and_line *) NULL;
 513 }
 514 #endif
 515
 516 #if !defined(CHILD_GET_CURRENT_EXCEPTION_EVENT)
 517 struct exception_event_record *
 518 child_get_current_exception_event (void)
 519 {
 520   return (struct exception_event_record *) NULL;
 521 }
 522 #endif
 523
 524
 525 #if !defined(CHILD_PID_TO_EXEC_FILE)
 526 char *
 527 child_pid_to_exec_file (int pid)
 528 {
 529   /* This version of Unix doesn't support translation of a process ID
 530      to the filename of the executable file.
 531    */
 532   return NULL;
 533 }
 534 #endif
 535
 536 char *
 537 child_core_file_to_sym_file (char *core)
 538 {
 539   /* The target stratum for a running executable need not support
 540      this operation.
 541    */
 542   return NULL;
 543 }
 544
 545 /* Perform a partial transfer to/from the specified object.  For
 546    memory transfers, fall back to the old memory xfer functions.  */
 547
 548 static LONGEST
 549 child_xfer_partial (struct target_ops *ops, enum target_object object,
 550                     const char *annex, void *readbuf,
 551                     const void *writebuf, ULONGEST offset, LONGEST len)
 552 {
 553   switch (object)
 554     {
 555     case TARGET_OBJECT_MEMORY:
 556       if (readbuf)
 557         return child_xfer_memory (offset, readbuf, len, 0/*write*/,
 558                                   NULL, ops);
 559       if (writebuf)
 560         return child_xfer_memory (offset, readbuf, len, 1/*write*/,
 561                                   NULL, ops);
 562       return -1;
 563
 564     case TARGET_OBJECT_UNWIND_TABLE:
 565 #ifndef NATIVE_XFER_UNWIND_TABLE
 566 #define NATIVE_XFER_UNWIND_TABLE(OPS,OBJECT,ANNEX,WRITEBUF,READBUF,OFFSET,LEN) (-1)
 567 #endif
 568       return NATIVE_XFER_UNWIND_TABLE (ops, object, annex, readbuf, writebuf,
 569                                        offset, len);
 570
 571     case TARGET_OBJECT_AUXV:
 572 #ifndef NATIVE_XFER_AUXV
 573 #define NATIVE_XFER_AUXV(OPS,OBJECT,ANNEX,WRITEBUF,READBUF,OFFSET,LEN) (-1)
 574 #endif
 575       return NATIVE_XFER_AUXV (ops, object, annex, readbuf, writebuf,
 576                                offset, len);
 577
 578     case TARGET_OBJECT_WCOOKIE:
 579 #ifndef NATIVE_XFER_WCOOKIE
 580 #define NATIVE_XFER_WCOOKIE(OPS,OBJECT,ANNEX,WRITEBUF,READBUF,OFFSET,LEN) (-1)
 581 #endif
 582       return NATIVE_XFER_WCOOKIE (ops, object, annex, readbuf, writebuf,
 583                                   offset, len);
 584
 585     default:
 586       return -1;
 587     }
 588 }
 589
 590 #if !defined(CHILD_PID_TO_STR)
 591 char *
 592 child_pid_to_str (ptid_t ptid)
 593 {
 594   return normal_pid_to_str (ptid);
 595 }
 596 #endif
 597
 598 static void
 599 init_child_ops (void)
 600 {
 601   child_ops.to_shortname = "child";
 602   child_ops.to_longname = "Unix child process";
 603   child_ops.to_doc = "Unix child process (started by the \"run\" command).";
 604   child_ops.to_open = child_open;
 605   child_ops.to_attach = child_attach;
 606   child_ops.to_post_attach = child_post_attach;
 607   child_ops.to_detach = child_detach;
 608   child_ops.to_resume = child_resume;
 609   child_ops.to_wait = child_wait;
 610   child_ops.to_post_wait = child_post_wait;
 611   child_ops.to_fetch_registers = fetch_inferior_registers;
 612   child_ops.to_store_registers = store_inferior_registers;
 613   child_ops.to_prepare_to_store = child_prepare_to_store;
 614   child_ops.to_xfer_memory = child_xfer_memory;
 615   child_ops.to_xfer_partial = child_xfer_partial;
 616   child_ops.to_files_info = child_files_info;
 617   child_ops.to_insert_breakpoint = memory_insert_breakpoint;
 618   child_ops.to_remove_breakpoint = memory_remove_breakpoint;
 619   child_ops.to_terminal_init = terminal_init_inferior;
 620   child_ops.to_terminal_inferior = terminal_inferior;
 621   child_ops.to_terminal_ours_for_output = terminal_ours_for_output;
 622   child_ops.to_terminal_save_ours = terminal_save_ours;
 623   child_ops.to_terminal_ours = terminal_ours;
 624   child_ops.to_terminal_info = child_terminal_info;
 625   child_ops.to_kill = kill_inferior;
 626   child_ops.to_create_inferior = child_create_inferior;
 627   child_ops.to_post_startup_inferior = child_post_startup_inferior;
 628   child_ops.to_acknowledge_created_inferior = child_acknowledge_created_inferior;
 629   child_ops.to_insert_fork_catchpoint = child_insert_fork_catchpoint;
 630   child_ops.to_remove_fork_catchpoint = child_remove_fork_catchpoint;
 631   child_ops.to_insert_vfork_catchpoint = child_insert_vfork_catchpoint;
 632   child_ops.to_remove_vfork_catchpoint = child_remove_vfork_catchpoint;
 633   child_ops.to_follow_fork = child_follow_fork;
 634   child_ops.to_insert_exec_catchpoint = child_insert_exec_catchpoint;
 635   child_ops.to_remove_exec_catchpoint = child_remove_exec_catchpoint;
 636   child_ops.to_reported_exec_events_per_exec_call = child_reported_exec_events_per_exec_call;
 637   child_ops.to_has_exited = child_has_exited;
 638   child_ops.to_mourn_inferior = child_mourn_inferior;
 639   child_ops.to_can_run = child_can_run;
 640   child_ops.to_thread_alive = child_thread_alive;
 641   child_ops.to_pid_to_str = child_pid_to_str;
 642   child_ops.to_stop = child_stop;
 643   child_ops.to_enable_exception_callback = child_enable_exception_callback;
 644   child_ops.to_get_current_exception_event = child_get_current_exception_event;
 645   child_ops.to_pid_to_exec_file = child_pid_to_exec_file;
 646   child_ops.to_stratum = process_stratum;
 647   child_ops.to_has_all_memory = 1;
 648   child_ops.to_has_memory = 1;
 649   child_ops.to_has_stack = 1;
 650   child_ops.to_has_registers = 1;
 651   child_ops.to_has_execution = 1;
 652   child_ops.to_magic = OPS_MAGIC;
 653 }
 654
 655 /* Take over the 'find_mapped_memory' vector from inftarg.c. */
 656 extern void
 657 inftarg_set_find_memory_regions (int (*func) (int (*) (CORE_ADDR,
 658                                                        unsigned long,
 659                                                        int, int, int,
 660                                                        void *),
 661                                               void *))
 662 {
 663   child_ops.to_find_memory_regions = func;
 664 }
 665
 666 /* Take over the 'make_corefile_notes' vector from inftarg.c. */
 667 extern void
 668 inftarg_set_make_corefile_notes (char * (*func) (bfd *, int *))
 669 {
 670   child_ops.to_make_corefile_notes = func;
 671 }
 672
 673 void
 674 _initialize_inftarg (void)
 675 {
 676 #ifdef HAVE_OPTIONAL_PROC_FS
 677   char procname[32];
 678   int fd;
 679
 680   /* If we have an optional /proc filesystem (e.g. under OSF/1),
 681      don't add ptrace support if we can access the running GDB via /proc.  */
 682 #ifndef PROC_NAME_FMT
 683 #define PROC_NAME_FMT "/proc/%05d"
 684 #endif
 685   sprintf (procname, PROC_NAME_FMT, getpid ());
 686   fd = open (procname, O_RDONLY);
 687   if (fd >= 0)
 688     {
 689       close (fd);
 690       return;
 691     }
 692 #endif
 693
 694   init_child_ops ();
 695   add_target (&child_ops);
 696 }