1/* GNU/Linux native-dependent code for debugging multiple forks. 2 3 Copyright (C) 2005-2020 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20#include "defs.h" 21#include "arch-utils.h" 22#include "inferior.h" 23#include "infrun.h" 24#include "regcache.h" 25#include "gdbcmd.h" 26#include "infcall.h" 27#include "objfiles.h" 28#include "linux-fork.h" 29#include "linux-nat.h" 30#include "gdbthread.h" 31#include "source.h" 32 33#include "nat/gdb_ptrace.h" 34#include "gdbsupport/gdb_wait.h" 35#include <dirent.h> 36#include <ctype.h> 37 38#include <list> 39 40/* Fork list data structure: */ 41struct fork_info 42{ 43 explicit fork_info (pid_t pid) 44 : ptid (pid, pid, 0) 45 { 46 } 47 48 ~fork_info () 49 { 50 /* Notes on step-resume breakpoints: since this is a concern for 51 threads, let's convince ourselves that it's not a concern for 52 forks. There are two ways for a fork_info to be created. 53 First, by the checkpoint command, in which case we're at a gdb 54 prompt and there can't be any step-resume breakpoint. Second, 55 by a fork in the user program, in which case we *may* have 56 stepped into the fork call, but regardless of whether we follow 57 the parent or the child, we will return to the same place and 58 the step-resume breakpoint, if any, will take care of itself as 59 usual. And unlike threads, we do not save a private copy of 60 the step-resume breakpoint -- so we're OK. */ 61 62 if (savedregs) 63 delete savedregs; 64 65 xfree (filepos); 66 } 67 68 ptid_t ptid = null_ptid; 69 ptid_t parent_ptid = null_ptid; 70 71 /* Convenient handle (GDB fork id). */ 72 int num = 0; 73 74 /* Convenient for info fork, saves having to actually switch 75 contexts. */ 76 readonly_detached_regcache *savedregs = nullptr; 77 78 CORE_ADDR pc = 0; 79 80 /* Set of open file descriptors' offsets. */ 81 off_t *filepos = nullptr; 82 83 int maxfd = 0; 84}; 85 86static std::list<fork_info> fork_list; 87static int highest_fork_num; 88 89/* Fork list methods: */ 90 91int 92forks_exist_p (void) 93{ 94 return !fork_list.empty (); 95} 96 97/* Return the last fork in the list. */ 98 99static struct fork_info * 100find_last_fork (void) 101{ 102 if (fork_list.empty ()) 103 return NULL; 104 105 return &fork_list.back (); 106} 107 108/* Return true iff there's one fork in the list. */ 109 110static bool 111one_fork_p () 112{ 113 return fork_list.size () == 1; 114} 115 116/* Add a new fork to the internal fork list. */ 117 118void 119add_fork (pid_t pid) 120{ 121 fork_list.emplace_back (pid); 122 123 if (one_fork_p ()) 124 highest_fork_num = 0; 125 126 fork_info *fp = &fork_list.back (); 127 fp->num = ++highest_fork_num; 128} 129 130static void 131delete_fork (ptid_t ptid) 132{ 133 linux_target->low_forget_process (ptid.pid ()); 134 135 for (auto it = fork_list.begin (); it != fork_list.end (); ++it) 136 if (it->ptid == ptid) 137 { 138 fork_list.erase (it); 139 140 /* Special case: if there is now only one process in the list, 141 and if it is (hopefully!) the current inferior_ptid, then 142 remove it, leaving the list empty -- we're now down to the 143 default case of debugging a single process. */ 144 if (one_fork_p () && fork_list.front ().ptid == inferior_ptid) 145 { 146 /* Last fork -- delete from list and handle as solo 147 process (should be a safe recursion). */ 148 delete_fork (inferior_ptid); 149 } 150 return; 151 } 152} 153 154/* Find a fork_info by matching PTID. */ 155static struct fork_info * 156find_fork_ptid (ptid_t ptid) 157{ 158 for (fork_info &fi : fork_list) 159 if (fi.ptid == ptid) 160 return &fi; 161 162 return NULL; 163} 164 165/* Find a fork_info by matching ID. */ 166static struct fork_info * 167find_fork_id (int num) 168{ 169 for (fork_info &fi : fork_list) 170 if (fi.num == num) 171 return &fi; 172 173 return NULL; 174} 175 176/* Find a fork_info by matching pid. */ 177extern struct fork_info * 178find_fork_pid (pid_t pid) 179{ 180 for (fork_info &fi : fork_list) 181 if (pid == fi.ptid.pid ()) 182 return &fi; 183 184 return NULL; 185} 186 187static ptid_t 188fork_id_to_ptid (int num) 189{ 190 struct fork_info *fork = find_fork_id (num); 191 if (fork) 192 return fork->ptid; 193 else 194 return ptid_t (-1); 195} 196 197/* Fork list <-> gdb interface. */ 198 199/* Utility function for fork_load/fork_save. 200 Calls lseek in the (current) inferior process. */ 201 202static off_t 203call_lseek (int fd, off_t offset, int whence) 204{ 205 char exp[80]; 206 207 snprintf (&exp[0], sizeof (exp), "(long) lseek (%d, %ld, %d)", 208 fd, (long) offset, whence); 209 return (off_t) parse_and_eval_long (&exp[0]); 210} 211 212/* Load infrun state for the fork PTID. */ 213 214static void 215fork_load_infrun_state (struct fork_info *fp) 216{ 217 int i; 218 219 linux_nat_switch_fork (fp->ptid); 220 221 if (fp->savedregs) 222 get_current_regcache ()->restore (fp->savedregs); 223 224 registers_changed (); 225 reinit_frame_cache (); 226 227 inferior_thread ()->suspend.stop_pc 228 = regcache_read_pc (get_current_regcache ()); 229 nullify_last_target_wait_ptid (); 230 231 /* Now restore the file positions of open file descriptors. */ 232 if (fp->filepos) 233 { 234 for (i = 0; i <= fp->maxfd; i++) 235 if (fp->filepos[i] != (off_t) -1) 236 call_lseek (i, fp->filepos[i], SEEK_SET); 237 /* NOTE: I can get away with using SEEK_SET and SEEK_CUR because 238 this is native-only. If it ever has to be cross, we'll have 239 to rethink this. */ 240 } 241} 242 243/* Save infrun state for the fork FP. */ 244 245static void 246fork_save_infrun_state (struct fork_info *fp) 247{ 248 char path[PATH_MAX]; 249 struct dirent *de; 250 DIR *d; 251 252 if (fp->savedregs) 253 delete fp->savedregs; 254 255 fp->savedregs = new readonly_detached_regcache (*get_current_regcache ()); 256 fp->pc = regcache_read_pc (get_current_regcache ()); 257 258 /* Now save the 'state' (file position) of all open file descriptors. 259 Unfortunately fork does not take care of that for us... */ 260 snprintf (path, PATH_MAX, "/proc/%ld/fd", (long) fp->ptid.pid ()); 261 if ((d = opendir (path)) != NULL) 262 { 263 long tmp; 264 265 fp->maxfd = 0; 266 while ((de = readdir (d)) != NULL) 267 { 268 /* Count open file descriptors (actually find highest 269 numbered). */ 270 tmp = strtol (&de->d_name[0], NULL, 10); 271 if (fp->maxfd < tmp) 272 fp->maxfd = tmp; 273 } 274 /* Allocate array of file positions. */ 275 fp->filepos = XRESIZEVEC (off_t, fp->filepos, fp->maxfd + 1); 276 277 /* Initialize to -1 (invalid). */ 278 for (tmp = 0; tmp <= fp->maxfd; tmp++) 279 fp->filepos[tmp] = -1; 280 281 /* Now find actual file positions. */ 282 rewinddir (d); 283 while ((de = readdir (d)) != NULL) 284 if (isdigit (de->d_name[0])) 285 { 286 tmp = strtol (&de->d_name[0], NULL, 10); 287 fp->filepos[tmp] = call_lseek (tmp, 0, SEEK_CUR); 288 } 289 closedir (d); 290 } 291} 292 293/* Kill 'em all, let God sort 'em out... */ 294 295void 296linux_fork_killall (void) 297{ 298 /* Walk list and kill every pid. No need to treat the 299 current inferior_ptid as special (we do not return a 300 status for it) -- however any process may be a child 301 or a parent, so may get a SIGCHLD from a previously 302 killed child. Wait them all out. */ 303 304 for (fork_info &fi : fork_list) 305 { 306 pid_t pid = fi.ptid.pid (); 307 int status; 308 pid_t ret; 309 do { 310 /* Use SIGKILL instead of PTRACE_KILL because the former works even 311 if the thread is running, while the later doesn't. */ 312 kill (pid, SIGKILL); 313 ret = waitpid (pid, &status, 0); 314 /* We might get a SIGCHLD instead of an exit status. This is 315 aggravated by the first kill above - a child has just 316 died. MVS comment cut-and-pasted from linux-nat. */ 317 } while (ret == pid && WIFSTOPPED (status)); 318 } 319 320 /* Clear list, prepare to start fresh. */ 321 fork_list.clear (); 322} 323 324/* The current inferior_ptid has exited, but there are other viable 325 forks to debug. Delete the exiting one and context-switch to the 326 first available. */ 327 328void 329linux_fork_mourn_inferior (void) 330{ 331 struct fork_info *last; 332 int status; 333 334 /* Wait just one more time to collect the inferior's exit status. 335 Do not check whether this succeeds though, since we may be 336 dealing with a process that we attached to. Such a process will 337 only report its exit status to its original parent. */ 338 waitpid (inferior_ptid.pid (), &status, 0); 339 340 /* OK, presumably inferior_ptid is the one who has exited. 341 We need to delete that one from the fork_list, and switch 342 to the next available fork. */ 343 delete_fork (inferior_ptid); 344 345 /* There should still be a fork - if there's only one left, 346 delete_fork won't remove it, because we haven't updated 347 inferior_ptid yet. */ 348 gdb_assert (!fork_list.empty ()); 349 350 last = find_last_fork (); 351 fork_load_infrun_state (last); 352 printf_filtered (_("[Switching to %s]\n"), 353 target_pid_to_str (inferior_ptid).c_str ()); 354 355 /* If there's only one fork, switch back to non-fork mode. */ 356 if (one_fork_p ()) 357 delete_fork (inferior_ptid); 358} 359 360/* The current inferior_ptid is being detached, but there are other 361 viable forks to debug. Detach and delete it and context-switch to 362 the first available. */ 363 364void 365linux_fork_detach (int from_tty) 366{ 367 /* OK, inferior_ptid is the one we are detaching from. We need to 368 delete it from the fork_list, and switch to the next available 369 fork. */ 370 371 if (ptrace (PTRACE_DETACH, inferior_ptid.pid (), 0, 0)) 372 error (_("Unable to detach %s"), 373 target_pid_to_str (inferior_ptid).c_str ()); 374 375 delete_fork (inferior_ptid); 376 377 /* There should still be a fork - if there's only one left, 378 delete_fork won't remove it, because we haven't updated 379 inferior_ptid yet. */ 380 gdb_assert (!fork_list.empty ()); 381 382 fork_load_infrun_state (&fork_list.front ()); 383 384 if (from_tty) 385 printf_filtered (_("[Switching to %s]\n"), 386 target_pid_to_str (inferior_ptid).c_str ()); 387 388 /* If there's only one fork, switch back to non-fork mode. */ 389 if (one_fork_p ()) 390 delete_fork (inferior_ptid); 391} 392 393/* Temporarily switch to the infrun state stored on the fork_info 394 identified by a given ptid_t. When this object goes out of scope, 395 restore the currently selected infrun state. */ 396 397class scoped_switch_fork_info 398{ 399public: 400 /* Switch to the infrun state held on the fork_info identified by 401 PPTID. If PPTID is the current inferior then no switch is done. */ 402 explicit scoped_switch_fork_info (ptid_t pptid) 403 : m_oldfp (nullptr) 404 { 405 if (pptid != inferior_ptid) 406 { 407 struct fork_info *newfp = nullptr; 408 409 /* Switch to pptid. */ 410 m_oldfp = find_fork_ptid (inferior_ptid); 411 gdb_assert (m_oldfp != nullptr); 412 newfp = find_fork_ptid (pptid); 413 gdb_assert (newfp != nullptr); 414 fork_save_infrun_state (m_oldfp); 415 remove_breakpoints (); 416 fork_load_infrun_state (newfp); 417 insert_breakpoints (); 418 } 419 } 420 421 /* Restore the previously selected infrun state. If the constructor 422 didn't need to switch states, then nothing is done here either. */ 423 ~scoped_switch_fork_info () 424 { 425 if (m_oldfp != nullptr) 426 { 427 /* Switch back to inferior_ptid. */ 428 try 429 { 430 remove_breakpoints (); 431 fork_load_infrun_state (m_oldfp); 432 insert_breakpoints (); 433 } 434 catch (const gdb_exception &ex) 435 { 436 warning (_("Couldn't restore checkpoint state in %s: %s"), 437 target_pid_to_str (m_oldfp->ptid).c_str (), 438 ex.what ()); 439 } 440 } 441 } 442 443 DISABLE_COPY_AND_ASSIGN (scoped_switch_fork_info); 444 445private: 446 /* The fork_info for the previously selected infrun state, or nullptr if 447 we were already in the desired state, and nothing needs to be 448 restored. */ 449 struct fork_info *m_oldfp; 450}; 451 452static int 453inferior_call_waitpid (ptid_t pptid, int pid) 454{ 455 struct objfile *waitpid_objf; 456 struct value *waitpid_fn = NULL; 457 int ret = -1; 458 459 scoped_switch_fork_info switch_fork_info (pptid); 460 461 /* Get the waitpid_fn. */ 462 if (lookup_minimal_symbol ("waitpid", NULL, NULL).minsym != NULL) 463 waitpid_fn = find_function_in_inferior ("waitpid", &waitpid_objf); 464 if (!waitpid_fn 465 && lookup_minimal_symbol ("_waitpid", NULL, NULL).minsym != NULL) 466 waitpid_fn = find_function_in_inferior ("_waitpid", &waitpid_objf); 467 if (waitpid_fn != nullptr) 468 { 469 struct gdbarch *gdbarch = get_current_arch (); 470 struct value *argv[3], *retv; 471 472 /* Get the argv. */ 473 argv[0] = value_from_longest (builtin_type (gdbarch)->builtin_int, pid); 474 argv[1] = value_from_pointer (builtin_type (gdbarch)->builtin_data_ptr, 0); 475 argv[2] = value_from_longest (builtin_type (gdbarch)->builtin_int, 0); 476 477 retv = call_function_by_hand (waitpid_fn, NULL, argv); 478 479 if (value_as_long (retv) >= 0) 480 ret = 0; 481 } 482 483 return ret; 484} 485 486/* Fork list <-> user interface. */ 487 488static void 489delete_checkpoint_command (const char *args, int from_tty) 490{ 491 ptid_t ptid, pptid; 492 struct fork_info *fi; 493 494 if (!args || !*args) 495 error (_("Requires argument (checkpoint id to delete)")); 496 497 ptid = fork_id_to_ptid (parse_and_eval_long (args)); 498 if (ptid == minus_one_ptid) 499 error (_("No such checkpoint id, %s"), args); 500 501 if (ptid == inferior_ptid) 502 error (_("\ 503Please switch to another checkpoint before deleting the current one")); 504 505 if (ptrace (PTRACE_KILL, ptid.pid (), 0, 0)) 506 error (_("Unable to kill pid %s"), target_pid_to_str (ptid).c_str ()); 507 508 fi = find_fork_ptid (ptid); 509 gdb_assert (fi); 510 pptid = fi->parent_ptid; 511 512 if (from_tty) 513 printf_filtered (_("Killed %s\n"), target_pid_to_str (ptid).c_str ()); 514 515 delete_fork (ptid); 516 517 /* If fi->parent_ptid is not a part of lwp but it's a part of checkpoint 518 list, waitpid the ptid. 519 If fi->parent_ptid is a part of lwp and it is stopped, waitpid the 520 ptid. */ 521 thread_info *parent = find_thread_ptid (linux_target, pptid); 522 if ((parent == NULL && find_fork_ptid (pptid)) 523 || (parent != NULL && parent->state == THREAD_STOPPED)) 524 { 525 if (inferior_call_waitpid (pptid, ptid.pid ())) 526 warning (_("Unable to wait pid %s"), 527 target_pid_to_str (ptid).c_str ()); 528 } 529} 530 531static void 532detach_checkpoint_command (const char *args, int from_tty) 533{ 534 ptid_t ptid; 535 536 if (!args || !*args) 537 error (_("Requires argument (checkpoint id to detach)")); 538 539 ptid = fork_id_to_ptid (parse_and_eval_long (args)); 540 if (ptid == minus_one_ptid) 541 error (_("No such checkpoint id, %s"), args); 542 543 if (ptid == inferior_ptid) 544 error (_("\ 545Please switch to another checkpoint before detaching the current one")); 546 547 if (ptrace (PTRACE_DETACH, ptid.pid (), 0, 0)) 548 error (_("Unable to detach %s"), target_pid_to_str (ptid).c_str ()); 549 550 if (from_tty) 551 printf_filtered (_("Detached %s\n"), target_pid_to_str (ptid).c_str ()); 552 553 delete_fork (ptid); 554} 555 556/* Print information about currently known checkpoints. */ 557 558static void 559info_checkpoints_command (const char *arg, int from_tty) 560{ 561 struct gdbarch *gdbarch = get_current_arch (); 562 int requested = -1; 563 const fork_info *printed = NULL; 564 565 if (arg && *arg) 566 requested = (int) parse_and_eval_long (arg); 567 568 for (const fork_info &fi : fork_list) 569 { 570 if (requested > 0 && fi.num != requested) 571 continue; 572 573 printed = &fi; 574 if (fi.ptid == inferior_ptid) 575 printf_filtered ("* "); 576 else 577 printf_filtered (" "); 578 579 ULONGEST pc = fi.pc; 580 printf_filtered ("%d %s", fi.num, target_pid_to_str (fi.ptid).c_str ()); 581 if (fi.num == 0) 582 printf_filtered (_(" (main process)")); 583 printf_filtered (_(" at ")); 584 fputs_filtered (paddress (gdbarch, pc), gdb_stdout); 585 586 symtab_and_line sal = find_pc_line (pc, 0); 587 if (sal.symtab) 588 printf_filtered (_(", file %s"), 589 symtab_to_filename_for_display (sal.symtab)); 590 if (sal.line) 591 printf_filtered (_(", line %d"), sal.line); 592 if (!sal.symtab && !sal.line) 593 { 594 struct bound_minimal_symbol msym; 595 596 msym = lookup_minimal_symbol_by_pc (pc); 597 if (msym.minsym) 598 printf_filtered (", <%s>", msym.minsym->linkage_name ()); 599 } 600 601 putchar_filtered ('\n'); 602 } 603 if (printed == NULL) 604 { 605 if (requested > 0) 606 printf_filtered (_("No checkpoint number %d.\n"), requested); 607 else 608 printf_filtered (_("No checkpoints.\n")); 609 } 610} 611 612/* The PID of the process we're checkpointing. */ 613static int checkpointing_pid = 0; 614 615int 616linux_fork_checkpointing_p (int pid) 617{ 618 return (checkpointing_pid == pid); 619} 620 621/* Return true if the current inferior is multi-threaded. */ 622 623static bool 624inf_has_multiple_threads () 625{ 626 int count = 0; 627 628 /* Return true as soon as we see the second thread of the current 629 inferior. */ 630 for (thread_info *tp ATTRIBUTE_UNUSED : current_inferior ()->threads ()) 631 if (++count > 1) 632 return true; 633 634 return false; 635} 636 637static void 638checkpoint_command (const char *args, int from_tty) 639{ 640 struct objfile *fork_objf; 641 struct gdbarch *gdbarch; 642 struct target_waitstatus last_target_waitstatus; 643 ptid_t last_target_ptid; 644 struct value *fork_fn = NULL, *ret; 645 struct fork_info *fp; 646 pid_t retpid; 647 648 if (!target_has_execution) 649 error (_("The program is not being run.")); 650 651 /* Ensure that the inferior is not multithreaded. */ 652 update_thread_list (); 653 if (inf_has_multiple_threads ()) 654 error (_("checkpoint: can't checkpoint multiple threads.")); 655 656 /* Make the inferior fork, record its (and gdb's) state. */ 657 658 if (lookup_minimal_symbol ("fork", NULL, NULL).minsym != NULL) 659 fork_fn = find_function_in_inferior ("fork", &fork_objf); 660 if (!fork_fn) 661 if (lookup_minimal_symbol ("_fork", NULL, NULL).minsym != NULL) 662 fork_fn = find_function_in_inferior ("fork", &fork_objf); 663 if (!fork_fn) 664 error (_("checkpoint: can't find fork function in inferior.")); 665 666 gdbarch = fork_objf->arch (); 667 ret = value_from_longest (builtin_type (gdbarch)->builtin_int, 0); 668 669 /* Tell linux-nat.c that we're checkpointing this inferior. */ 670 { 671 scoped_restore save_pid 672 = make_scoped_restore (&checkpointing_pid, inferior_ptid.pid ()); 673 674 ret = call_function_by_hand (fork_fn, NULL, {}); 675 } 676 677 if (!ret) /* Probably can't happen. */ 678 error (_("checkpoint: call_function_by_hand returned null.")); 679 680 retpid = value_as_long (ret); 681 get_last_target_status (nullptr, &last_target_ptid, &last_target_waitstatus); 682 683 fp = find_fork_pid (retpid); 684 685 if (from_tty) 686 { 687 int parent_pid; 688 689 printf_filtered (_("checkpoint %d: fork returned pid %ld.\n"), 690 fp != NULL ? fp->num : -1, (long) retpid); 691 if (info_verbose) 692 { 693 parent_pid = last_target_ptid.lwp (); 694 if (parent_pid == 0) 695 parent_pid = last_target_ptid.pid (); 696 printf_filtered (_(" gdb says parent = %ld.\n"), 697 (long) parent_pid); 698 } 699 } 700 701 if (!fp) 702 error (_("Failed to find new fork")); 703 704 if (one_fork_p ()) 705 { 706 /* Special case -- if this is the first fork in the list (the 707 list was hitherto empty), then add inferior_ptid first, as a 708 special zeroeth fork id. */ 709 fork_list.emplace_front (inferior_ptid.pid ()); 710 } 711 712 fork_save_infrun_state (fp); 713 fp->parent_ptid = last_target_ptid; 714} 715 716static void 717linux_fork_context (struct fork_info *newfp, int from_tty) 718{ 719 /* Now we attempt to switch processes. */ 720 struct fork_info *oldfp; 721 722 gdb_assert (newfp != NULL); 723 724 oldfp = find_fork_ptid (inferior_ptid); 725 gdb_assert (oldfp != NULL); 726 727 fork_save_infrun_state (oldfp); 728 remove_breakpoints (); 729 fork_load_infrun_state (newfp); 730 insert_breakpoints (); 731 732 printf_filtered (_("Switching to %s\n"), 733 target_pid_to_str (inferior_ptid).c_str ()); 734 735 print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC, 1); 736} 737 738/* Switch inferior process (checkpoint) context, by checkpoint id. */ 739static void 740restart_command (const char *args, int from_tty) 741{ 742 struct fork_info *fp; 743 744 if (!args || !*args) 745 error (_("Requires argument (checkpoint id to restart)")); 746 747 if ((fp = find_fork_id (parse_and_eval_long (args))) == NULL) 748 error (_("Not found: checkpoint id %s"), args); 749 750 linux_fork_context (fp, from_tty); 751} 752 753void _initialize_linux_fork (); 754void 755_initialize_linux_fork () 756{ 757 /* Checkpoint command: create a fork of the inferior process 758 and set it aside for later debugging. */ 759 760 add_com ("checkpoint", class_obscure, checkpoint_command, _("\ 761Fork a duplicate process (experimental).")); 762 763 /* Restart command: restore the context of a specified checkpoint 764 process. */ 765 766 add_com ("restart", class_obscure, restart_command, _("\ 767Restore program context from a checkpoint.\n\ 768Usage: restart N\n\ 769Argument N is checkpoint ID, as displayed by 'info checkpoints'.")); 770 771 /* Delete checkpoint command: kill the process and remove it from 772 the fork list. */ 773 774 add_cmd ("checkpoint", class_obscure, delete_checkpoint_command, _("\ 775Delete a checkpoint (experimental)."), 776 &deletelist); 777 778 /* Detach checkpoint command: release the process to run independently, 779 and remove it from the fork list. */ 780 781 add_cmd ("checkpoint", class_obscure, detach_checkpoint_command, _("\ 782Detach from a checkpoint (experimental)."), 783 &detachlist); 784 785 /* Info checkpoints command: list all forks/checkpoints 786 currently under gdb's control. */ 787 788 add_info ("checkpoints", info_checkpoints_command, 789 _("IDs of currently known checkpoints.")); 790} 791