| 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: */ |
| 41 | struct 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 | if (filepos) |
| 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 | |
| 86 | static std::list<fork_info> fork_list; |
| 87 | static int highest_fork_num; |
| 88 | |
| 89 | /* Fork list methods: */ |
| 90 | |
| 91 | int |
| 92 | forks_exist_p (void) |
| 93 | { |
| 94 | return !fork_list.empty (); |
| 95 | } |
| 96 | |
| 97 | /* Return the last fork in the list. */ |
| 98 | |
| 99 | static struct fork_info * |
| 100 | find_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 | |
| 110 | static bool |
| 111 | one_fork_p () |
| 112 | { |
| 113 | return fork_list.size () == 1; |
| 114 | } |
| 115 | |
| 116 | /* Add a new fork to the internal fork list. */ |
| 117 | |
| 118 | void |
| 119 | add_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 | |
| 130 | static void |
| 131 | delete_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. */ |
| 155 | static struct fork_info * |
| 156 | find_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. */ |
| 166 | static struct fork_info * |
| 167 | find_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. */ |
| 177 | extern struct fork_info * |
| 178 | find_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 | |
| 187 | static ptid_t |
| 188 | fork_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 | |
| 202 | static off_t |
| 203 | call_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 | |
| 214 | static void |
| 215 | fork_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 | |
| 245 | static void |
| 246 | fork_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 | |
| 295 | void |
| 296 | linux_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 | |
| 328 | void |
| 329 | linux_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 | |
| 364 | void |
| 365 | linux_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 | |
| 397 | class scoped_switch_fork_info |
| 398 | { |
| 399 | public: |
| 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 | |
| 445 | private: |
| 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 | |
| 452 | static int |
| 453 | inferior_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 | |
| 488 | static void |
| 489 | delete_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 (_("\ |
| 503 | Please 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 | |
| 531 | static void |
| 532 | detach_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 (_("\ |
| 545 | Please 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 | |
| 558 | static void |
| 559 | info_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. */ |
| 613 | static int checkpointing_pid = 0; |
| 614 | |
| 615 | int |
| 616 | linux_fork_checkpointing_p (int pid) |
| 617 | { |
| 618 | return (checkpointing_pid == pid); |
| 619 | } |
| 620 | |
| 621 | /* Return true if the current inferior is multi-threaded. */ |
| 622 | |
| 623 | static bool |
| 624 | inf_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 | |
| 637 | static void |
| 638 | checkpoint_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 = get_objfile_arch (fork_objf); |
| 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 | |
| 716 | static void |
| 717 | linux_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. */ |
| 739 | static void |
| 740 | restart_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 | |
| 753 | void _initialize_linux_fork (); |
| 754 | void |
| 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, _("\ |
| 761 | Fork 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, _("\ |
| 767 | Restore program context from a checkpoint.\n\ |
| 768 | Usage: restart N\n\ |
| 769 | Argument 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, _("\ |
| 775 | Delete 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, _("\ |
| 782 | Detach 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 | } |