| 1 | /* Native-dependent code for FreeBSD. |
| 2 | |
| 3 | Copyright (C) 2002-2015 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 "gdbcore.h" |
| 22 | #include "inferior.h" |
| 23 | #include "regcache.h" |
| 24 | #include "regset.h" |
| 25 | #include "gdbthread.h" |
| 26 | #include "gdb_wait.h" |
| 27 | #include <sys/types.h> |
| 28 | #include <sys/procfs.h> |
| 29 | #include <sys/ptrace.h> |
| 30 | #include <sys/sysctl.h> |
| 31 | #ifdef HAVE_KINFO_GETVMMAP |
| 32 | #include <sys/user.h> |
| 33 | #include <libutil.h> |
| 34 | #endif |
| 35 | |
| 36 | #include "elf-bfd.h" |
| 37 | #include "fbsd-nat.h" |
| 38 | |
| 39 | /* Return the name of a file that can be opened to get the symbols for |
| 40 | the child process identified by PID. */ |
| 41 | |
| 42 | static char * |
| 43 | fbsd_pid_to_exec_file (struct target_ops *self, int pid) |
| 44 | { |
| 45 | ssize_t len = PATH_MAX; |
| 46 | static char buf[PATH_MAX]; |
| 47 | char name[PATH_MAX]; |
| 48 | |
| 49 | #ifdef KERN_PROC_PATHNAME |
| 50 | int mib[4]; |
| 51 | |
| 52 | mib[0] = CTL_KERN; |
| 53 | mib[1] = KERN_PROC; |
| 54 | mib[2] = KERN_PROC_PATHNAME; |
| 55 | mib[3] = pid; |
| 56 | if (sysctl (mib, 4, buf, &len, NULL, 0) == 0) |
| 57 | return buf; |
| 58 | #endif |
| 59 | |
| 60 | xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid); |
| 61 | len = readlink (name, buf, PATH_MAX - 1); |
| 62 | if (len != -1) |
| 63 | { |
| 64 | buf[len] = '\0'; |
| 65 | return buf; |
| 66 | } |
| 67 | |
| 68 | return NULL; |
| 69 | } |
| 70 | |
| 71 | #ifdef HAVE_KINFO_GETVMMAP |
| 72 | /* Iterate over all the memory regions in the current inferior, |
| 73 | calling FUNC for each memory region. OBFD is passed as the last |
| 74 | argument to FUNC. */ |
| 75 | |
| 76 | static int |
| 77 | fbsd_find_memory_regions (struct target_ops *self, |
| 78 | find_memory_region_ftype func, void *obfd) |
| 79 | { |
| 80 | pid_t pid = ptid_get_pid (inferior_ptid); |
| 81 | struct kinfo_vmentry *vmentl, *kve; |
| 82 | uint64_t size; |
| 83 | struct cleanup *cleanup; |
| 84 | int i, nitems; |
| 85 | |
| 86 | vmentl = kinfo_getvmmap (pid, &nitems); |
| 87 | if (vmentl == NULL) |
| 88 | perror_with_name (_("Couldn't fetch VM map entries.")); |
| 89 | cleanup = make_cleanup (free, vmentl); |
| 90 | |
| 91 | for (i = 0; i < nitems; i++) |
| 92 | { |
| 93 | kve = &vmentl[i]; |
| 94 | |
| 95 | /* Skip unreadable segments and those where MAP_NOCORE has been set. */ |
| 96 | if (!(kve->kve_protection & KVME_PROT_READ) |
| 97 | || kve->kve_flags & KVME_FLAG_NOCOREDUMP) |
| 98 | continue; |
| 99 | |
| 100 | /* Skip segments with an invalid type. */ |
| 101 | if (kve->kve_type != KVME_TYPE_DEFAULT |
| 102 | && kve->kve_type != KVME_TYPE_VNODE |
| 103 | && kve->kve_type != KVME_TYPE_SWAP |
| 104 | && kve->kve_type != KVME_TYPE_PHYS) |
| 105 | continue; |
| 106 | |
| 107 | size = kve->kve_end - kve->kve_start; |
| 108 | if (info_verbose) |
| 109 | { |
| 110 | fprintf_filtered (gdb_stdout, |
| 111 | "Save segment, %ld bytes at %s (%c%c%c)\n", |
| 112 | (long) size, |
| 113 | paddress (target_gdbarch (), kve->kve_start), |
| 114 | kve->kve_protection & KVME_PROT_READ ? 'r' : '-', |
| 115 | kve->kve_protection & KVME_PROT_WRITE ? 'w' : '-', |
| 116 | kve->kve_protection & KVME_PROT_EXEC ? 'x' : '-'); |
| 117 | } |
| 118 | |
| 119 | /* Invoke the callback function to create the corefile segment. |
| 120 | Pass MODIFIED as true, we do not know the real modification state. */ |
| 121 | func (kve->kve_start, size, kve->kve_protection & KVME_PROT_READ, |
| 122 | kve->kve_protection & KVME_PROT_WRITE, |
| 123 | kve->kve_protection & KVME_PROT_EXEC, 1, obfd); |
| 124 | } |
| 125 | do_cleanups (cleanup); |
| 126 | return 0; |
| 127 | } |
| 128 | #else |
| 129 | static int |
| 130 | fbsd_read_mapping (FILE *mapfile, unsigned long *start, unsigned long *end, |
| 131 | char *protection) |
| 132 | { |
| 133 | /* FreeBSD 5.1-RELEASE uses a 256-byte buffer. */ |
| 134 | char buf[256]; |
| 135 | int resident, privateresident; |
| 136 | unsigned long obj; |
| 137 | int ret = EOF; |
| 138 | |
| 139 | /* As of FreeBSD 5.0-RELEASE, the layout is described in |
| 140 | /usr/src/sys/fs/procfs/procfs_map.c. Somewhere in 5.1-CURRENT a |
| 141 | new column was added to the procfs map. Therefore we can't use |
| 142 | fscanf since we need to support older releases too. */ |
| 143 | if (fgets (buf, sizeof buf, mapfile) != NULL) |
| 144 | ret = sscanf (buf, "%lx %lx %d %d %lx %s", start, end, |
| 145 | &resident, &privateresident, &obj, protection); |
| 146 | |
| 147 | return (ret != 0 && ret != EOF); |
| 148 | } |
| 149 | |
| 150 | /* Iterate over all the memory regions in the current inferior, |
| 151 | calling FUNC for each memory region. OBFD is passed as the last |
| 152 | argument to FUNC. */ |
| 153 | |
| 154 | static int |
| 155 | fbsd_find_memory_regions (struct target_ops *self, |
| 156 | find_memory_region_ftype func, void *obfd) |
| 157 | { |
| 158 | pid_t pid = ptid_get_pid (inferior_ptid); |
| 159 | char *mapfilename; |
| 160 | FILE *mapfile; |
| 161 | unsigned long start, end, size; |
| 162 | char protection[4]; |
| 163 | int read, write, exec; |
| 164 | struct cleanup *cleanup; |
| 165 | |
| 166 | mapfilename = xstrprintf ("/proc/%ld/map", (long) pid); |
| 167 | cleanup = make_cleanup (xfree, mapfilename); |
| 168 | mapfile = fopen (mapfilename, "r"); |
| 169 | if (mapfile == NULL) |
| 170 | error (_("Couldn't open %s."), mapfilename); |
| 171 | make_cleanup_fclose (mapfile); |
| 172 | |
| 173 | if (info_verbose) |
| 174 | fprintf_filtered (gdb_stdout, |
| 175 | "Reading memory regions from %s\n", mapfilename); |
| 176 | |
| 177 | /* Now iterate until end-of-file. */ |
| 178 | while (fbsd_read_mapping (mapfile, &start, &end, &protection[0])) |
| 179 | { |
| 180 | size = end - start; |
| 181 | |
| 182 | read = (strchr (protection, 'r') != 0); |
| 183 | write = (strchr (protection, 'w') != 0); |
| 184 | exec = (strchr (protection, 'x') != 0); |
| 185 | |
| 186 | if (info_verbose) |
| 187 | { |
| 188 | fprintf_filtered (gdb_stdout, |
| 189 | "Save segment, %ld bytes at %s (%c%c%c)\n", |
| 190 | size, paddress (target_gdbarch (), start), |
| 191 | read ? 'r' : '-', |
| 192 | write ? 'w' : '-', |
| 193 | exec ? 'x' : '-'); |
| 194 | } |
| 195 | |
| 196 | /* Invoke the callback function to create the corefile segment. |
| 197 | Pass MODIFIED as true, we do not know the real modification state. */ |
| 198 | func (start, size, read, write, exec, 1, obfd); |
| 199 | } |
| 200 | |
| 201 | do_cleanups (cleanup); |
| 202 | return 0; |
| 203 | } |
| 204 | #endif |
| 205 | |
| 206 | #ifdef PT_LWPINFO |
| 207 | static ptid_t (*super_wait) (struct target_ops *, |
| 208 | ptid_t, |
| 209 | struct target_waitstatus *, |
| 210 | int); |
| 211 | |
| 212 | #ifdef TDP_RFPPWAIT |
| 213 | /* |
| 214 | To catch fork events, PT_FOLLOW_FORK is set on every traced process |
| 215 | to enable stops on returns from fork or vfork. Note that both the |
| 216 | parent and child will always stop, even if system call stops are not |
| 217 | enabled. |
| 218 | |
| 219 | After a fork, both the child and parent process will stop and report |
| 220 | an event. However, there is no guarantee of order. If the parent |
| 221 | reports its stop first, then fbsd_wait explicitly waits for the new |
| 222 | child before returning. If the child reports its stop first, then |
| 223 | the event is saved on a list and ignored until the parent's stop is |
| 224 | reported. fbsd_wait could have been changed to fetch the parent PID |
| 225 | of the new child and used that to wait for the parent explicitly. |
| 226 | However, if two threads in the parent fork at the same time, then |
| 227 | the wait on the parent might return the "wrong" fork event. |
| 228 | |
| 229 | The initial version of PT_FOLLOW_FORK did not set PL_FLAG_CHILD for |
| 230 | the new child process. This flag could be inferred by treating any |
| 231 | events for an unknown pid as a new child. |
| 232 | |
| 233 | In addition, the initial version of PT_FOLLOW_FORK did not report a |
| 234 | stop event for the parent process of a vfork until after the child |
| 235 | process executed a new program or exited. The kernel was changed to |
| 236 | defer the wait for exit or exec of the child until after posting the |
| 237 | stop event shortly after the change to introduce PL_FLAG_CHILD. |
| 238 | This could be worked around by reporting a vfork event when the |
| 239 | child event posted and ignoring the subsequent event from the |
| 240 | parent. |
| 241 | |
| 242 | This implementation requires both of these fixes for simplicity's |
| 243 | sake. FreeBSD versions newer than 9.1 contain both fixes. |
| 244 | */ |
| 245 | |
| 246 | struct fbsd_fork_child_info |
| 247 | { |
| 248 | struct fbsd_fork_child_info *next; |
| 249 | pid_t child; /* Pid of new child. */ |
| 250 | }; |
| 251 | |
| 252 | static struct fbsd_fork_child_info *fbsd_pending_children; |
| 253 | |
| 254 | /* Record a new child process event that is reported before the |
| 255 | corresponding fork event in the parent. */ |
| 256 | |
| 257 | static void |
| 258 | fbsd_remember_child (pid_t pid) |
| 259 | { |
| 260 | struct fbsd_fork_child_info *info; |
| 261 | |
| 262 | info = xcalloc (1, sizeof *info); |
| 263 | |
| 264 | info->child = pid; |
| 265 | info->next = fbsd_pending_children; |
| 266 | fbsd_pending_children = info; |
| 267 | } |
| 268 | |
| 269 | /* Check for a previously-recorded new child process event for PID. |
| 270 | If one is found, remove it from the list. */ |
| 271 | |
| 272 | static int |
| 273 | fbsd_is_child_pending (pid_t pid) |
| 274 | { |
| 275 | struct fbsd_fork_child_info *info, *prev; |
| 276 | |
| 277 | prev = NULL; |
| 278 | for (info = fbsd_pending_children; info; prev = info, info = info->next) |
| 279 | { |
| 280 | if (info->child == pid) |
| 281 | { |
| 282 | if (prev == NULL) |
| 283 | fbsd_pending_children = info->next; |
| 284 | else |
| 285 | prev->next = info->next; |
| 286 | xfree (info); |
| 287 | return 1; |
| 288 | } |
| 289 | } |
| 290 | return 0; |
| 291 | } |
| 292 | |
| 293 | /* Fetch the external variant of the kernel's internal process |
| 294 | structure for the process PID into KP. */ |
| 295 | |
| 296 | static void |
| 297 | fbsd_fetch_kinfo_proc (pid_t pid, struct kinfo_proc *kp) |
| 298 | { |
| 299 | size_t len; |
| 300 | int mib[4]; |
| 301 | |
| 302 | len = sizeof *kp; |
| 303 | mib[0] = CTL_KERN; |
| 304 | mib[1] = KERN_PROC; |
| 305 | mib[2] = KERN_PROC_PID; |
| 306 | mib[3] = pid; |
| 307 | if (sysctl (mib, 4, kp, &len, NULL, 0) == -1) |
| 308 | perror_with_name (("sysctl")); |
| 309 | } |
| 310 | #endif |
| 311 | |
| 312 | /* Wait for the child specified by PTID to do something. Return the |
| 313 | process ID of the child, or MINUS_ONE_PTID in case of error; store |
| 314 | the status in *OURSTATUS. */ |
| 315 | |
| 316 | static ptid_t |
| 317 | fbsd_wait (struct target_ops *ops, |
| 318 | ptid_t ptid, struct target_waitstatus *ourstatus, |
| 319 | int target_options) |
| 320 | { |
| 321 | ptid_t wptid; |
| 322 | |
| 323 | while (1) |
| 324 | { |
| 325 | wptid = super_wait (ops, ptid, ourstatus, target_options); |
| 326 | if (ourstatus->kind == TARGET_WAITKIND_STOPPED) |
| 327 | { |
| 328 | struct ptrace_lwpinfo pl; |
| 329 | pid_t pid; |
| 330 | int status; |
| 331 | |
| 332 | pid = ptid_get_pid (wptid); |
| 333 | if (ptrace (PT_LWPINFO, pid, (caddr_t)&pl, sizeof pl) == -1) |
| 334 | perror_with_name (("ptrace")); |
| 335 | |
| 336 | #ifdef TDP_RFPPWAIT |
| 337 | if (pl.pl_flags & PL_FLAG_FORKED) |
| 338 | { |
| 339 | struct kinfo_proc kp; |
| 340 | pid_t child; |
| 341 | |
| 342 | child = pl.pl_child_pid; |
| 343 | ourstatus->kind = TARGET_WAITKIND_FORKED; |
| 344 | ourstatus->value.related_pid = pid_to_ptid (child); |
| 345 | |
| 346 | /* Make sure the other end of the fork is stopped too. */ |
| 347 | if (!fbsd_is_child_pending (child)) |
| 348 | { |
| 349 | pid = waitpid (child, &status, 0); |
| 350 | if (pid == -1) |
| 351 | perror_with_name (("waitpid")); |
| 352 | |
| 353 | gdb_assert (pid == child); |
| 354 | |
| 355 | if (ptrace (PT_LWPINFO, child, (caddr_t)&pl, sizeof pl) == -1) |
| 356 | perror_with_name (("ptrace")); |
| 357 | |
| 358 | gdb_assert (pl.pl_flags & PL_FLAG_CHILD); |
| 359 | } |
| 360 | |
| 361 | /* For vfork, the child process will have the P_PPWAIT |
| 362 | flag set. */ |
| 363 | fbsd_fetch_kinfo_proc (child, &kp); |
| 364 | if (kp.ki_flag & P_PPWAIT) |
| 365 | ourstatus->kind = TARGET_WAITKIND_VFORKED; |
| 366 | |
| 367 | return wptid; |
| 368 | } |
| 369 | |
| 370 | if (pl.pl_flags & PL_FLAG_CHILD) |
| 371 | { |
| 372 | /* Remember that this child forked, but do not report it |
| 373 | until the parent reports its corresponding fork |
| 374 | event. */ |
| 375 | fbsd_remember_child (ptid_get_pid (wptid)); |
| 376 | continue; |
| 377 | } |
| 378 | #endif |
| 379 | |
| 380 | #ifdef PL_FLAG_EXEC |
| 381 | if (pl.pl_flags & PL_FLAG_EXEC) |
| 382 | { |
| 383 | ourstatus->kind = TARGET_WAITKIND_EXECD; |
| 384 | ourstatus->value.execd_pathname |
| 385 | = xstrdup (fbsd_pid_to_exec_file (NULL, pid)); |
| 386 | return wptid; |
| 387 | } |
| 388 | #endif |
| 389 | } |
| 390 | return wptid; |
| 391 | } |
| 392 | } |
| 393 | |
| 394 | #ifdef TDP_RFPPWAIT |
| 395 | /* Target hook for follow_fork. On entry and at return inferior_ptid is |
| 396 | the ptid of the followed inferior. */ |
| 397 | |
| 398 | static int |
| 399 | fbsd_follow_fork (struct target_ops *ops, int follow_child, |
| 400 | int detach_fork) |
| 401 | { |
| 402 | if (!follow_child) |
| 403 | { |
| 404 | struct thread_info *tp = inferior_thread (); |
| 405 | pid_t child_pid = ptid_get_pid (tp->pending_follow.value.related_pid); |
| 406 | |
| 407 | /* Breakpoints have already been detached from the child by |
| 408 | infrun.c. */ |
| 409 | |
| 410 | if (ptrace (PT_DETACH, child_pid, (PTRACE_TYPE_ARG3)1, 0) == -1) |
| 411 | perror_with_name (("ptrace")); |
| 412 | } |
| 413 | |
| 414 | return 0; |
| 415 | } |
| 416 | |
| 417 | static int |
| 418 | fbsd_insert_fork_catchpoint (struct target_ops *self, int pid) |
| 419 | { |
| 420 | return 0; |
| 421 | } |
| 422 | |
| 423 | static int |
| 424 | fbsd_remove_fork_catchpoint (struct target_ops *self, int pid) |
| 425 | { |
| 426 | return 0; |
| 427 | } |
| 428 | |
| 429 | static int |
| 430 | fbsd_insert_vfork_catchpoint (struct target_ops *self, int pid) |
| 431 | { |
| 432 | return 0; |
| 433 | } |
| 434 | |
| 435 | static int |
| 436 | fbsd_remove_vfork_catchpoint (struct target_ops *self, int pid) |
| 437 | { |
| 438 | return 0; |
| 439 | } |
| 440 | |
| 441 | /* Enable fork tracing for a specific process. |
| 442 | |
| 443 | To catch fork events, PT_FOLLOW_FORK is set on every traced process |
| 444 | to enable stops on returns from fork or vfork. Note that both the |
| 445 | parent and child will always stop, even if system call stops are |
| 446 | not enabled. */ |
| 447 | |
| 448 | static void |
| 449 | fbsd_enable_follow_fork (pid_t pid) |
| 450 | { |
| 451 | if (ptrace (PT_FOLLOW_FORK, pid, (PTRACE_TYPE_ARG3)0, 1) == -1) |
| 452 | perror_with_name (("ptrace")); |
| 453 | } |
| 454 | |
| 455 | /* Implement the "to_post_startup_inferior" target_ops method. */ |
| 456 | |
| 457 | static void |
| 458 | fbsd_post_startup_inferior (struct target_ops *self, ptid_t pid) |
| 459 | { |
| 460 | fbsd_enable_follow_fork (ptid_get_pid (pid)); |
| 461 | } |
| 462 | |
| 463 | /* Implement the "to_post_attach" target_ops method. */ |
| 464 | |
| 465 | static void |
| 466 | fbsd_post_attach (struct target_ops *self, int pid) |
| 467 | { |
| 468 | fbsd_enable_follow_fork (pid); |
| 469 | } |
| 470 | #endif |
| 471 | |
| 472 | #ifdef PL_FLAG_EXEC |
| 473 | /* If the FreeBSD kernel supports PL_FLAG_EXEC, then traced processes |
| 474 | will always stop after exec. */ |
| 475 | |
| 476 | static int |
| 477 | fbsd_insert_exec_catchpoint (struct target_ops *self, int pid) |
| 478 | { |
| 479 | return 0; |
| 480 | } |
| 481 | |
| 482 | static int |
| 483 | fbsd_remove_exec_catchpoint (struct target_ops *self, int pid) |
| 484 | { |
| 485 | return 0; |
| 486 | } |
| 487 | #endif |
| 488 | #endif |
| 489 | |
| 490 | void |
| 491 | fbsd_nat_add_target (struct target_ops *t) |
| 492 | { |
| 493 | t->to_pid_to_exec_file = fbsd_pid_to_exec_file; |
| 494 | t->to_find_memory_regions = fbsd_find_memory_regions; |
| 495 | #ifdef PT_LWPINFO |
| 496 | super_wait = t->to_wait; |
| 497 | t->to_wait = fbsd_wait; |
| 498 | #ifdef TDP_RFPPWAIT |
| 499 | t->to_follow_fork = fbsd_follow_fork; |
| 500 | t->to_insert_fork_catchpoint = fbsd_insert_fork_catchpoint; |
| 501 | t->to_remove_fork_catchpoint = fbsd_remove_fork_catchpoint; |
| 502 | t->to_insert_vfork_catchpoint = fbsd_insert_vfork_catchpoint; |
| 503 | t->to_remove_vfork_catchpoint = fbsd_remove_vfork_catchpoint; |
| 504 | t->to_post_startup_inferior = fbsd_post_startup_inferior; |
| 505 | t->to_post_attach = fbsd_post_attach; |
| 506 | #endif |
| 507 | #ifdef PL_FLAG_EXEC |
| 508 | t->to_insert_exec_catchpoint = fbsd_insert_exec_catchpoint; |
| 509 | t->to_remove_exec_catchpoint = fbsd_remove_exec_catchpoint; |
| 510 | #endif |
| 511 | #endif |
| 512 | add_target (t); |
| 513 | } |