| 1 | /* GNU/Linux native-dependent code for debugging multiple forks. |
| 2 | |
| 3 | Copyright (C) 2005-2019 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 "gdb_wait.h" |
| 35 | #include <dirent.h> |
| 36 | #include <ctype.h> |
| 37 | |
| 38 | struct fork_info *fork_list; |
| 39 | static int highest_fork_num; |
| 40 | |
| 41 | /* Fork list data structure: */ |
| 42 | struct fork_info |
| 43 | { |
| 44 | struct fork_info *next; |
| 45 | ptid_t ptid; |
| 46 | ptid_t parent_ptid; |
| 47 | int num; /* Convenient handle (GDB fork id). */ |
| 48 | readonly_detached_regcache *savedregs; /* Convenient for info fork, saves |
| 49 | having to actually switch contexts. */ |
| 50 | CORE_ADDR pc; |
| 51 | int clobber_regs; /* True if we should restore saved regs. */ |
| 52 | off_t *filepos; /* Set of open file descriptors' offsets. */ |
| 53 | int maxfd; |
| 54 | }; |
| 55 | |
| 56 | /* Fork list methods: */ |
| 57 | |
| 58 | int |
| 59 | forks_exist_p (void) |
| 60 | { |
| 61 | return (fork_list != NULL); |
| 62 | } |
| 63 | |
| 64 | /* Return the last fork in the list. */ |
| 65 | |
| 66 | static struct fork_info * |
| 67 | find_last_fork (void) |
| 68 | { |
| 69 | struct fork_info *last; |
| 70 | |
| 71 | if (fork_list == NULL) |
| 72 | return NULL; |
| 73 | |
| 74 | for (last = fork_list; last->next != NULL; last = last->next) |
| 75 | ; |
| 76 | return last; |
| 77 | } |
| 78 | |
| 79 | /* Add a fork to the internal fork list. */ |
| 80 | |
| 81 | struct fork_info * |
| 82 | add_fork (pid_t pid) |
| 83 | { |
| 84 | struct fork_info *fp; |
| 85 | |
| 86 | if (fork_list == NULL && pid != inferior_ptid.pid ()) |
| 87 | { |
| 88 | /* Special case -- if this is the first fork in the list |
| 89 | (the list is hitherto empty), and if this new fork is |
| 90 | NOT the current inferior_ptid, then add inferior_ptid |
| 91 | first, as a special zeroeth fork id. */ |
| 92 | highest_fork_num = -1; |
| 93 | add_fork (inferior_ptid.pid ()); /* safe recursion */ |
| 94 | } |
| 95 | |
| 96 | fp = XCNEW (struct fork_info); |
| 97 | fp->ptid = ptid_t (pid, pid, 0); |
| 98 | fp->num = ++highest_fork_num; |
| 99 | |
| 100 | if (fork_list == NULL) |
| 101 | fork_list = fp; |
| 102 | else |
| 103 | { |
| 104 | struct fork_info *last = find_last_fork (); |
| 105 | |
| 106 | last->next = fp; |
| 107 | } |
| 108 | |
| 109 | return fp; |
| 110 | } |
| 111 | |
| 112 | static void |
| 113 | free_fork (struct fork_info *fp) |
| 114 | { |
| 115 | /* Notes on step-resume breakpoints: since this is a concern for |
| 116 | threads, let's convince ourselves that it's not a concern for |
| 117 | forks. There are two ways for a fork_info to be created. First, |
| 118 | by the checkpoint command, in which case we're at a gdb prompt |
| 119 | and there can't be any step-resume breakpoint. Second, by a fork |
| 120 | in the user program, in which case we *may* have stepped into the |
| 121 | fork call, but regardless of whether we follow the parent or the |
| 122 | child, we will return to the same place and the step-resume |
| 123 | breakpoint, if any, will take care of itself as usual. And |
| 124 | unlike threads, we do not save a private copy of the step-resume |
| 125 | breakpoint -- so we're OK. */ |
| 126 | |
| 127 | if (fp) |
| 128 | { |
| 129 | if (fp->savedregs) |
| 130 | delete fp->savedregs; |
| 131 | if (fp->filepos) |
| 132 | xfree (fp->filepos); |
| 133 | xfree (fp); |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | static void |
| 138 | delete_fork (ptid_t ptid) |
| 139 | { |
| 140 | struct fork_info *fp, *fpprev; |
| 141 | |
| 142 | fpprev = NULL; |
| 143 | |
| 144 | linux_target->low_forget_process (ptid.pid ()); |
| 145 | |
| 146 | for (fp = fork_list; fp; fpprev = fp, fp = fp->next) |
| 147 | if (fp->ptid == ptid) |
| 148 | break; |
| 149 | |
| 150 | if (!fp) |
| 151 | return; |
| 152 | |
| 153 | if (fpprev) |
| 154 | fpprev->next = fp->next; |
| 155 | else |
| 156 | fork_list = fp->next; |
| 157 | |
| 158 | free_fork (fp); |
| 159 | |
| 160 | /* Special case: if there is now only one process in the list, |
| 161 | and if it is (hopefully!) the current inferior_ptid, then |
| 162 | remove it, leaving the list empty -- we're now down to the |
| 163 | default case of debugging a single process. */ |
| 164 | if (fork_list != NULL && fork_list->next == NULL && |
| 165 | fork_list->ptid == inferior_ptid) |
| 166 | { |
| 167 | /* Last fork -- delete from list and handle as solo process |
| 168 | (should be a safe recursion). */ |
| 169 | delete_fork (inferior_ptid); |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | /* Find a fork_info by matching PTID. */ |
| 174 | static struct fork_info * |
| 175 | find_fork_ptid (ptid_t ptid) |
| 176 | { |
| 177 | struct fork_info *fp; |
| 178 | |
| 179 | for (fp = fork_list; fp; fp = fp->next) |
| 180 | if (fp->ptid == ptid) |
| 181 | return fp; |
| 182 | |
| 183 | return NULL; |
| 184 | } |
| 185 | |
| 186 | /* Find a fork_info by matching ID. */ |
| 187 | static struct fork_info * |
| 188 | find_fork_id (int num) |
| 189 | { |
| 190 | struct fork_info *fp; |
| 191 | |
| 192 | for (fp = fork_list; fp; fp = fp->next) |
| 193 | if (fp->num == num) |
| 194 | return fp; |
| 195 | |
| 196 | return NULL; |
| 197 | } |
| 198 | |
| 199 | /* Find a fork_info by matching pid. */ |
| 200 | extern struct fork_info * |
| 201 | find_fork_pid (pid_t pid) |
| 202 | { |
| 203 | struct fork_info *fp; |
| 204 | |
| 205 | for (fp = fork_list; fp; fp = fp->next) |
| 206 | if (pid == fp->ptid.pid ()) |
| 207 | return fp; |
| 208 | |
| 209 | return NULL; |
| 210 | } |
| 211 | |
| 212 | static ptid_t |
| 213 | fork_id_to_ptid (int num) |
| 214 | { |
| 215 | struct fork_info *fork = find_fork_id (num); |
| 216 | if (fork) |
| 217 | return fork->ptid; |
| 218 | else |
| 219 | return ptid_t (-1); |
| 220 | } |
| 221 | |
| 222 | static void |
| 223 | init_fork_list (void) |
| 224 | { |
| 225 | struct fork_info *fp, *fpnext; |
| 226 | |
| 227 | if (!fork_list) |
| 228 | return; |
| 229 | |
| 230 | for (fp = fork_list; fp; fp = fpnext) |
| 231 | { |
| 232 | fpnext = fp->next; |
| 233 | free_fork (fp); |
| 234 | } |
| 235 | |
| 236 | fork_list = NULL; |
| 237 | } |
| 238 | |
| 239 | /* Fork list <-> gdb interface. */ |
| 240 | |
| 241 | /* Utility function for fork_load/fork_save. |
| 242 | Calls lseek in the (current) inferior process. */ |
| 243 | |
| 244 | static off_t |
| 245 | call_lseek (int fd, off_t offset, int whence) |
| 246 | { |
| 247 | char exp[80]; |
| 248 | |
| 249 | snprintf (&exp[0], sizeof (exp), "(long) lseek (%d, %ld, %d)", |
| 250 | fd, (long) offset, whence); |
| 251 | return (off_t) parse_and_eval_long (&exp[0]); |
| 252 | } |
| 253 | |
| 254 | /* Load infrun state for the fork PTID. */ |
| 255 | |
| 256 | static void |
| 257 | fork_load_infrun_state (struct fork_info *fp) |
| 258 | { |
| 259 | extern void nullify_last_target_wait_ptid (); |
| 260 | int i; |
| 261 | |
| 262 | linux_nat_switch_fork (fp->ptid); |
| 263 | |
| 264 | if (fp->savedregs && fp->clobber_regs) |
| 265 | get_current_regcache ()->restore (fp->savedregs); |
| 266 | |
| 267 | registers_changed (); |
| 268 | reinit_frame_cache (); |
| 269 | |
| 270 | inferior_thread ()->suspend.stop_pc |
| 271 | = regcache_read_pc (get_current_regcache ()); |
| 272 | nullify_last_target_wait_ptid (); |
| 273 | |
| 274 | /* Now restore the file positions of open file descriptors. */ |
| 275 | if (fp->filepos) |
| 276 | { |
| 277 | for (i = 0; i <= fp->maxfd; i++) |
| 278 | if (fp->filepos[i] != (off_t) -1) |
| 279 | call_lseek (i, fp->filepos[i], SEEK_SET); |
| 280 | /* NOTE: I can get away with using SEEK_SET and SEEK_CUR because |
| 281 | this is native-only. If it ever has to be cross, we'll have |
| 282 | to rethink this. */ |
| 283 | } |
| 284 | } |
| 285 | |
| 286 | /* Save infrun state for the fork PTID. |
| 287 | Exported for use by linux child_follow_fork. */ |
| 288 | |
| 289 | static void |
| 290 | fork_save_infrun_state (struct fork_info *fp, int clobber_regs) |
| 291 | { |
| 292 | char path[PATH_MAX]; |
| 293 | struct dirent *de; |
| 294 | DIR *d; |
| 295 | |
| 296 | if (fp->savedregs) |
| 297 | delete fp->savedregs; |
| 298 | |
| 299 | fp->savedregs = new readonly_detached_regcache (*get_current_regcache ()); |
| 300 | fp->pc = regcache_read_pc (get_current_regcache ()); |
| 301 | fp->clobber_regs = clobber_regs; |
| 302 | |
| 303 | if (clobber_regs) |
| 304 | { |
| 305 | /* Now save the 'state' (file position) of all open file descriptors. |
| 306 | Unfortunately fork does not take care of that for us... */ |
| 307 | snprintf (path, PATH_MAX, "/proc/%ld/fd", |
| 308 | (long) fp->ptid.pid ()); |
| 309 | if ((d = opendir (path)) != NULL) |
| 310 | { |
| 311 | long tmp; |
| 312 | |
| 313 | fp->maxfd = 0; |
| 314 | while ((de = readdir (d)) != NULL) |
| 315 | { |
| 316 | /* Count open file descriptors (actually find highest |
| 317 | numbered). */ |
| 318 | tmp = strtol (&de->d_name[0], NULL, 10); |
| 319 | if (fp->maxfd < tmp) |
| 320 | fp->maxfd = tmp; |
| 321 | } |
| 322 | /* Allocate array of file positions. */ |
| 323 | fp->filepos = XRESIZEVEC (off_t, fp->filepos, fp->maxfd + 1); |
| 324 | |
| 325 | /* Initialize to -1 (invalid). */ |
| 326 | for (tmp = 0; tmp <= fp->maxfd; tmp++) |
| 327 | fp->filepos[tmp] = -1; |
| 328 | |
| 329 | /* Now find actual file positions. */ |
| 330 | rewinddir (d); |
| 331 | while ((de = readdir (d)) != NULL) |
| 332 | if (isdigit (de->d_name[0])) |
| 333 | { |
| 334 | tmp = strtol (&de->d_name[0], NULL, 10); |
| 335 | fp->filepos[tmp] = call_lseek (tmp, 0, SEEK_CUR); |
| 336 | } |
| 337 | closedir (d); |
| 338 | } |
| 339 | } |
| 340 | } |
| 341 | |
| 342 | /* Kill 'em all, let God sort 'em out... */ |
| 343 | |
| 344 | void |
| 345 | linux_fork_killall (void) |
| 346 | { |
| 347 | /* Walk list and kill every pid. No need to treat the |
| 348 | current inferior_ptid as special (we do not return a |
| 349 | status for it) -- however any process may be a child |
| 350 | or a parent, so may get a SIGCHLD from a previously |
| 351 | killed child. Wait them all out. */ |
| 352 | struct fork_info *fp; |
| 353 | pid_t pid, ret; |
| 354 | int status; |
| 355 | |
| 356 | for (fp = fork_list; fp; fp = fp->next) |
| 357 | { |
| 358 | pid = fp->ptid.pid (); |
| 359 | do { |
| 360 | /* Use SIGKILL instead of PTRACE_KILL because the former works even |
| 361 | if the thread is running, while the later doesn't. */ |
| 362 | kill (pid, SIGKILL); |
| 363 | ret = waitpid (pid, &status, 0); |
| 364 | /* We might get a SIGCHLD instead of an exit status. This is |
| 365 | aggravated by the first kill above - a child has just |
| 366 | died. MVS comment cut-and-pasted from linux-nat. */ |
| 367 | } while (ret == pid && WIFSTOPPED (status)); |
| 368 | } |
| 369 | init_fork_list (); /* Clear list, prepare to start fresh. */ |
| 370 | } |
| 371 | |
| 372 | /* The current inferior_ptid has exited, but there are other viable |
| 373 | forks to debug. Delete the exiting one and context-switch to the |
| 374 | first available. */ |
| 375 | |
| 376 | void |
| 377 | linux_fork_mourn_inferior (void) |
| 378 | { |
| 379 | struct fork_info *last; |
| 380 | int status; |
| 381 | |
| 382 | /* Wait just one more time to collect the inferior's exit status. |
| 383 | Do not check whether this succeeds though, since we may be |
| 384 | dealing with a process that we attached to. Such a process will |
| 385 | only report its exit status to its original parent. */ |
| 386 | waitpid (inferior_ptid.pid (), &status, 0); |
| 387 | |
| 388 | /* OK, presumably inferior_ptid is the one who has exited. |
| 389 | We need to delete that one from the fork_list, and switch |
| 390 | to the next available fork. */ |
| 391 | delete_fork (inferior_ptid); |
| 392 | |
| 393 | /* There should still be a fork - if there's only one left, |
| 394 | delete_fork won't remove it, because we haven't updated |
| 395 | inferior_ptid yet. */ |
| 396 | gdb_assert (fork_list); |
| 397 | |
| 398 | last = find_last_fork (); |
| 399 | fork_load_infrun_state (last); |
| 400 | printf_filtered (_("[Switching to %s]\n"), |
| 401 | target_pid_to_str (inferior_ptid)); |
| 402 | |
| 403 | /* If there's only one fork, switch back to non-fork mode. */ |
| 404 | if (fork_list->next == NULL) |
| 405 | delete_fork (inferior_ptid); |
| 406 | } |
| 407 | |
| 408 | /* The current inferior_ptid is being detached, but there are other |
| 409 | viable forks to debug. Detach and delete it and context-switch to |
| 410 | the first available. */ |
| 411 | |
| 412 | void |
| 413 | linux_fork_detach (int from_tty) |
| 414 | { |
| 415 | /* OK, inferior_ptid is the one we are detaching from. We need to |
| 416 | delete it from the fork_list, and switch to the next available |
| 417 | fork. */ |
| 418 | |
| 419 | if (ptrace (PTRACE_DETACH, inferior_ptid.pid (), 0, 0)) |
| 420 | error (_("Unable to detach %s"), target_pid_to_str (inferior_ptid)); |
| 421 | |
| 422 | delete_fork (inferior_ptid); |
| 423 | |
| 424 | /* There should still be a fork - if there's only one left, |
| 425 | delete_fork won't remove it, because we haven't updated |
| 426 | inferior_ptid yet. */ |
| 427 | gdb_assert (fork_list); |
| 428 | |
| 429 | fork_load_infrun_state (fork_list); |
| 430 | |
| 431 | if (from_tty) |
| 432 | printf_filtered (_("[Switching to %s]\n"), |
| 433 | target_pid_to_str (inferior_ptid)); |
| 434 | |
| 435 | /* If there's only one fork, switch back to non-fork mode. */ |
| 436 | if (fork_list->next == NULL) |
| 437 | delete_fork (inferior_ptid); |
| 438 | } |
| 439 | |
| 440 | /* Temporarily switch to the infrun state stored on the fork_info |
| 441 | identified by a given ptid_t. When this object goes out of scope, |
| 442 | restore the currently selected infrun state. */ |
| 443 | |
| 444 | class scoped_switch_fork_info |
| 445 | { |
| 446 | public: |
| 447 | /* Switch to the infrun state held on the fork_info identified by |
| 448 | PPTID. If PPTID is the current inferior then no switch is done. */ |
| 449 | explicit scoped_switch_fork_info (ptid_t pptid) |
| 450 | : m_oldfp (nullptr) |
| 451 | { |
| 452 | if (pptid != inferior_ptid) |
| 453 | { |
| 454 | struct fork_info *newfp = nullptr; |
| 455 | |
| 456 | /* Switch to pptid. */ |
| 457 | m_oldfp = find_fork_ptid (inferior_ptid); |
| 458 | gdb_assert (m_oldfp != nullptr); |
| 459 | newfp = find_fork_ptid (pptid); |
| 460 | gdb_assert (newfp != nullptr); |
| 461 | fork_save_infrun_state (m_oldfp, 1); |
| 462 | remove_breakpoints (); |
| 463 | fork_load_infrun_state (newfp); |
| 464 | insert_breakpoints (); |
| 465 | } |
| 466 | } |
| 467 | |
| 468 | /* Restore the previously selected infrun state. If the constructor |
| 469 | didn't need to switch states, then nothing is done here either. */ |
| 470 | ~scoped_switch_fork_info () |
| 471 | { |
| 472 | if (m_oldfp != nullptr) |
| 473 | { |
| 474 | /* Switch back to inferior_ptid. */ |
| 475 | TRY |
| 476 | { |
| 477 | remove_breakpoints (); |
| 478 | fork_load_infrun_state (m_oldfp); |
| 479 | insert_breakpoints (); |
| 480 | } |
| 481 | CATCH (ex, RETURN_MASK_ALL) |
| 482 | { |
| 483 | warning (_("Couldn't restore checkpoint state in %s: %s"), |
| 484 | target_pid_to_str (fp->ptid), ex.message); |
| 485 | } |
| 486 | END_CATCH |
| 487 | } |
| 488 | } |
| 489 | |
| 490 | DISABLE_COPY_AND_ASSIGN (scoped_switch_fork_info); |
| 491 | |
| 492 | private: |
| 493 | /* The fork_info for the previously selected infrun state, or nullptr if |
| 494 | we were already in the desired state, and nothing needs to be |
| 495 | restored. */ |
| 496 | struct fork_info *m_oldfp; |
| 497 | }; |
| 498 | |
| 499 | static int |
| 500 | inferior_call_waitpid (ptid_t pptid, int pid) |
| 501 | { |
| 502 | struct objfile *waitpid_objf; |
| 503 | struct value *waitpid_fn = NULL; |
| 504 | int ret = -1; |
| 505 | |
| 506 | scoped_switch_fork_info switch_fork_info (pptid); |
| 507 | |
| 508 | /* Get the waitpid_fn. */ |
| 509 | if (lookup_minimal_symbol ("waitpid", NULL, NULL).minsym != NULL) |
| 510 | waitpid_fn = find_function_in_inferior ("waitpid", &waitpid_objf); |
| 511 | if (!waitpid_fn |
| 512 | && lookup_minimal_symbol ("_waitpid", NULL, NULL).minsym != NULL) |
| 513 | waitpid_fn = find_function_in_inferior ("_waitpid", &waitpid_objf); |
| 514 | if (waitpid_fn != nullptr) |
| 515 | { |
| 516 | struct gdbarch *gdbarch = get_current_arch (); |
| 517 | struct value *argv[3], *retv; |
| 518 | |
| 519 | /* Get the argv. */ |
| 520 | argv[0] = value_from_longest (builtin_type (gdbarch)->builtin_int, pid); |
| 521 | argv[1] = value_from_pointer (builtin_type (gdbarch)->builtin_data_ptr, 0); |
| 522 | argv[2] = value_from_longest (builtin_type (gdbarch)->builtin_int, 0); |
| 523 | |
| 524 | retv = call_function_by_hand (waitpid_fn, NULL, argv); |
| 525 | |
| 526 | if (value_as_long (retv) >= 0) |
| 527 | ret = 0; |
| 528 | } |
| 529 | |
| 530 | return ret; |
| 531 | } |
| 532 | |
| 533 | /* Fork list <-> user interface. */ |
| 534 | |
| 535 | static void |
| 536 | delete_checkpoint_command (const char *args, int from_tty) |
| 537 | { |
| 538 | ptid_t ptid, pptid; |
| 539 | struct fork_info *fi; |
| 540 | |
| 541 | if (!args || !*args) |
| 542 | error (_("Requires argument (checkpoint id to delete)")); |
| 543 | |
| 544 | ptid = fork_id_to_ptid (parse_and_eval_long (args)); |
| 545 | if (ptid == minus_one_ptid) |
| 546 | error (_("No such checkpoint id, %s"), args); |
| 547 | |
| 548 | if (ptid == inferior_ptid) |
| 549 | error (_("\ |
| 550 | Please switch to another checkpoint before deleting the current one")); |
| 551 | |
| 552 | if (ptrace (PTRACE_KILL, ptid.pid (), 0, 0)) |
| 553 | error (_("Unable to kill pid %s"), target_pid_to_str (ptid)); |
| 554 | |
| 555 | fi = find_fork_ptid (ptid); |
| 556 | gdb_assert (fi); |
| 557 | pptid = fi->parent_ptid; |
| 558 | |
| 559 | if (from_tty) |
| 560 | printf_filtered (_("Killed %s\n"), target_pid_to_str (ptid)); |
| 561 | |
| 562 | delete_fork (ptid); |
| 563 | |
| 564 | /* If fi->parent_ptid is not a part of lwp but it's a part of checkpoint |
| 565 | list, waitpid the ptid. |
| 566 | If fi->parent_ptid is a part of lwp and it is stopped, waitpid the |
| 567 | ptid. */ |
| 568 | thread_info *parent = find_thread_ptid (pptid); |
| 569 | if ((parent == NULL && find_fork_ptid (pptid)) |
| 570 | || (parent != NULL && parent->state == THREAD_STOPPED)) |
| 571 | { |
| 572 | if (inferior_call_waitpid (pptid, ptid.pid ())) |
| 573 | warning (_("Unable to wait pid %s"), target_pid_to_str (ptid)); |
| 574 | } |
| 575 | } |
| 576 | |
| 577 | static void |
| 578 | detach_checkpoint_command (const char *args, int from_tty) |
| 579 | { |
| 580 | ptid_t ptid; |
| 581 | |
| 582 | if (!args || !*args) |
| 583 | error (_("Requires argument (checkpoint id to detach)")); |
| 584 | |
| 585 | ptid = fork_id_to_ptid (parse_and_eval_long (args)); |
| 586 | if (ptid == minus_one_ptid) |
| 587 | error (_("No such checkpoint id, %s"), args); |
| 588 | |
| 589 | if (ptid == inferior_ptid) |
| 590 | error (_("\ |
| 591 | Please switch to another checkpoint before detaching the current one")); |
| 592 | |
| 593 | if (ptrace (PTRACE_DETACH, ptid.pid (), 0, 0)) |
| 594 | error (_("Unable to detach %s"), target_pid_to_str (ptid)); |
| 595 | |
| 596 | if (from_tty) |
| 597 | printf_filtered (_("Detached %s\n"), target_pid_to_str (ptid)); |
| 598 | |
| 599 | delete_fork (ptid); |
| 600 | } |
| 601 | |
| 602 | /* Print information about currently known checkpoints. */ |
| 603 | |
| 604 | static void |
| 605 | info_checkpoints_command (const char *arg, int from_tty) |
| 606 | { |
| 607 | struct gdbarch *gdbarch = get_current_arch (); |
| 608 | struct symtab_and_line sal; |
| 609 | struct fork_info *fp; |
| 610 | ULONGEST pc; |
| 611 | int requested = -1; |
| 612 | struct fork_info *printed = NULL; |
| 613 | |
| 614 | if (arg && *arg) |
| 615 | requested = (int) parse_and_eval_long (arg); |
| 616 | |
| 617 | for (fp = fork_list; fp; fp = fp->next) |
| 618 | { |
| 619 | if (requested > 0 && fp->num != requested) |
| 620 | continue; |
| 621 | |
| 622 | printed = fp; |
| 623 | if (fp->ptid == inferior_ptid) |
| 624 | printf_filtered ("* "); |
| 625 | else |
| 626 | printf_filtered (" "); |
| 627 | |
| 628 | pc = fp->pc; |
| 629 | printf_filtered ("%d %s", fp->num, target_pid_to_str (fp->ptid)); |
| 630 | if (fp->num == 0) |
| 631 | printf_filtered (_(" (main process)")); |
| 632 | printf_filtered (_(" at ")); |
| 633 | fputs_filtered (paddress (gdbarch, pc), gdb_stdout); |
| 634 | |
| 635 | sal = find_pc_line (pc, 0); |
| 636 | if (sal.symtab) |
| 637 | printf_filtered (_(", file %s"), |
| 638 | symtab_to_filename_for_display (sal.symtab)); |
| 639 | if (sal.line) |
| 640 | printf_filtered (_(", line %d"), sal.line); |
| 641 | if (!sal.symtab && !sal.line) |
| 642 | { |
| 643 | struct bound_minimal_symbol msym; |
| 644 | |
| 645 | msym = lookup_minimal_symbol_by_pc (pc); |
| 646 | if (msym.minsym) |
| 647 | printf_filtered (", <%s>", MSYMBOL_LINKAGE_NAME (msym.minsym)); |
| 648 | } |
| 649 | |
| 650 | putchar_filtered ('\n'); |
| 651 | } |
| 652 | if (printed == NULL) |
| 653 | { |
| 654 | if (requested > 0) |
| 655 | printf_filtered (_("No checkpoint number %d.\n"), requested); |
| 656 | else |
| 657 | printf_filtered (_("No checkpoints.\n")); |
| 658 | } |
| 659 | } |
| 660 | |
| 661 | /* The PID of the process we're checkpointing. */ |
| 662 | static int checkpointing_pid = 0; |
| 663 | |
| 664 | int |
| 665 | linux_fork_checkpointing_p (int pid) |
| 666 | { |
| 667 | return (checkpointing_pid == pid); |
| 668 | } |
| 669 | |
| 670 | /* Callback for iterate over threads. Used to check whether |
| 671 | the current inferior is multi-threaded. Returns true as soon |
| 672 | as it sees the second thread of the current inferior. */ |
| 673 | |
| 674 | static int |
| 675 | inf_has_multiple_thread_cb (struct thread_info *tp, void *data) |
| 676 | { |
| 677 | int *count_p = (int *) data; |
| 678 | |
| 679 | if (current_inferior ()->pid == tp->ptid.pid ()) |
| 680 | (*count_p)++; |
| 681 | |
| 682 | /* Stop the iteration if multiple threads have been detected. */ |
| 683 | return *count_p > 1; |
| 684 | } |
| 685 | |
| 686 | /* Return true if the current inferior is multi-threaded. */ |
| 687 | |
| 688 | static int |
| 689 | inf_has_multiple_threads (void) |
| 690 | { |
| 691 | int count = 0; |
| 692 | |
| 693 | iterate_over_threads (inf_has_multiple_thread_cb, &count); |
| 694 | return (count > 1); |
| 695 | } |
| 696 | |
| 697 | static void |
| 698 | checkpoint_command (const char *args, int from_tty) |
| 699 | { |
| 700 | struct objfile *fork_objf; |
| 701 | struct gdbarch *gdbarch; |
| 702 | struct target_waitstatus last_target_waitstatus; |
| 703 | ptid_t last_target_ptid; |
| 704 | struct value *fork_fn = NULL, *ret; |
| 705 | struct fork_info *fp; |
| 706 | pid_t retpid; |
| 707 | |
| 708 | if (!target_has_execution) |
| 709 | error (_("The program is not being run.")); |
| 710 | |
| 711 | /* Ensure that the inferior is not multithreaded. */ |
| 712 | update_thread_list (); |
| 713 | if (inf_has_multiple_threads ()) |
| 714 | error (_("checkpoint: can't checkpoint multiple threads.")); |
| 715 | |
| 716 | /* Make the inferior fork, record its (and gdb's) state. */ |
| 717 | |
| 718 | if (lookup_minimal_symbol ("fork", NULL, NULL).minsym != NULL) |
| 719 | fork_fn = find_function_in_inferior ("fork", &fork_objf); |
| 720 | if (!fork_fn) |
| 721 | if (lookup_minimal_symbol ("_fork", NULL, NULL).minsym != NULL) |
| 722 | fork_fn = find_function_in_inferior ("fork", &fork_objf); |
| 723 | if (!fork_fn) |
| 724 | error (_("checkpoint: can't find fork function in inferior.")); |
| 725 | |
| 726 | gdbarch = get_objfile_arch (fork_objf); |
| 727 | ret = value_from_longest (builtin_type (gdbarch)->builtin_int, 0); |
| 728 | |
| 729 | /* Tell linux-nat.c that we're checkpointing this inferior. */ |
| 730 | { |
| 731 | scoped_restore save_pid |
| 732 | = make_scoped_restore (&checkpointing_pid, inferior_ptid.pid ()); |
| 733 | |
| 734 | ret = call_function_by_hand (fork_fn, NULL, {}); |
| 735 | } |
| 736 | |
| 737 | if (!ret) /* Probably can't happen. */ |
| 738 | error (_("checkpoint: call_function_by_hand returned null.")); |
| 739 | |
| 740 | retpid = value_as_long (ret); |
| 741 | get_last_target_status (&last_target_ptid, &last_target_waitstatus); |
| 742 | |
| 743 | fp = find_fork_pid (retpid); |
| 744 | |
| 745 | if (from_tty) |
| 746 | { |
| 747 | int parent_pid; |
| 748 | |
| 749 | printf_filtered (_("checkpoint %d: fork returned pid %ld.\n"), |
| 750 | fp != NULL ? fp->num : -1, (long) retpid); |
| 751 | if (info_verbose) |
| 752 | { |
| 753 | parent_pid = last_target_ptid.lwp (); |
| 754 | if (parent_pid == 0) |
| 755 | parent_pid = last_target_ptid.pid (); |
| 756 | printf_filtered (_(" gdb says parent = %ld.\n"), |
| 757 | (long) parent_pid); |
| 758 | } |
| 759 | } |
| 760 | |
| 761 | if (!fp) |
| 762 | error (_("Failed to find new fork")); |
| 763 | fork_save_infrun_state (fp, 1); |
| 764 | fp->parent_ptid = last_target_ptid; |
| 765 | } |
| 766 | |
| 767 | static void |
| 768 | linux_fork_context (struct fork_info *newfp, int from_tty) |
| 769 | { |
| 770 | /* Now we attempt to switch processes. */ |
| 771 | struct fork_info *oldfp; |
| 772 | |
| 773 | gdb_assert (newfp != NULL); |
| 774 | |
| 775 | oldfp = find_fork_ptid (inferior_ptid); |
| 776 | gdb_assert (oldfp != NULL); |
| 777 | |
| 778 | fork_save_infrun_state (oldfp, 1); |
| 779 | remove_breakpoints (); |
| 780 | fork_load_infrun_state (newfp); |
| 781 | insert_breakpoints (); |
| 782 | |
| 783 | printf_filtered (_("Switching to %s\n"), |
| 784 | target_pid_to_str (inferior_ptid)); |
| 785 | |
| 786 | print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC, 1); |
| 787 | } |
| 788 | |
| 789 | /* Switch inferior process (checkpoint) context, by checkpoint id. */ |
| 790 | static void |
| 791 | restart_command (const char *args, int from_tty) |
| 792 | { |
| 793 | struct fork_info *fp; |
| 794 | |
| 795 | if (!args || !*args) |
| 796 | error (_("Requires argument (checkpoint id to restart)")); |
| 797 | |
| 798 | if ((fp = find_fork_id (parse_and_eval_long (args))) == NULL) |
| 799 | error (_("Not found: checkpoint id %s"), args); |
| 800 | |
| 801 | linux_fork_context (fp, from_tty); |
| 802 | } |
| 803 | |
| 804 | void |
| 805 | _initialize_linux_fork (void) |
| 806 | { |
| 807 | init_fork_list (); |
| 808 | |
| 809 | /* Checkpoint command: create a fork of the inferior process |
| 810 | and set it aside for later debugging. */ |
| 811 | |
| 812 | add_com ("checkpoint", class_obscure, checkpoint_command, _("\ |
| 813 | Fork a duplicate process (experimental).")); |
| 814 | |
| 815 | /* Restart command: restore the context of a specified checkpoint |
| 816 | process. */ |
| 817 | |
| 818 | add_com ("restart", class_obscure, restart_command, _("\ |
| 819 | restart N: restore program context from a checkpoint.\n\ |
| 820 | Argument N is checkpoint ID, as displayed by 'info checkpoints'.")); |
| 821 | |
| 822 | /* Delete checkpoint command: kill the process and remove it from |
| 823 | the fork list. */ |
| 824 | |
| 825 | add_cmd ("checkpoint", class_obscure, delete_checkpoint_command, _("\ |
| 826 | Delete a checkpoint (experimental)."), |
| 827 | &deletelist); |
| 828 | |
| 829 | /* Detach checkpoint command: release the process to run independently, |
| 830 | and remove it from the fork list. */ |
| 831 | |
| 832 | add_cmd ("checkpoint", class_obscure, detach_checkpoint_command, _("\ |
| 833 | Detach from a checkpoint (experimental)."), |
| 834 | &detachlist); |
| 835 | |
| 836 | /* Info checkpoints command: list all forks/checkpoints |
| 837 | currently under gdb's control. */ |
| 838 | |
| 839 | add_info ("checkpoints", info_checkpoints_command, |
| 840 | _("IDs of currently known checkpoints.")); |
| 841 | } |