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3993f6b1 | 1 | /* GNU/Linux native-dependent code common to multiple platforms. |
a2f23071 | 2 | Copyright (C) 2003, 2004 Free Software Foundation, Inc. |
3993f6b1 DJ |
3 | |
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | #include "defs.h" | |
22 | #include "inferior.h" | |
23 | #include "target.h" | |
d6b0e80f | 24 | #include "gdb_string.h" |
3993f6b1 | 25 | #include "gdb_wait.h" |
d6b0e80f AC |
26 | #include "gdb_assert.h" |
27 | #ifdef HAVE_TKILL_SYSCALL | |
28 | #include <unistd.h> | |
29 | #include <sys/syscall.h> | |
30 | #endif | |
3993f6b1 | 31 | #include <sys/ptrace.h> |
0274a8ce | 32 | #include "linux-nat.h" |
d6b0e80f AC |
33 | #include "gdbthread.h" |
34 | #include "gdbcmd.h" | |
35 | #include "regcache.h" | |
0274a8ce | 36 | |
3993f6b1 DJ |
37 | /* If the system headers did not provide the constants, hard-code the normal |
38 | values. */ | |
39 | #ifndef PTRACE_EVENT_FORK | |
40 | ||
41 | #define PTRACE_SETOPTIONS 0x4200 | |
42 | #define PTRACE_GETEVENTMSG 0x4201 | |
43 | ||
44 | /* options set using PTRACE_SETOPTIONS */ | |
45 | #define PTRACE_O_TRACESYSGOOD 0x00000001 | |
46 | #define PTRACE_O_TRACEFORK 0x00000002 | |
47 | #define PTRACE_O_TRACEVFORK 0x00000004 | |
48 | #define PTRACE_O_TRACECLONE 0x00000008 | |
49 | #define PTRACE_O_TRACEEXEC 0x00000010 | |
9016a515 DJ |
50 | #define PTRACE_O_TRACEVFORKDONE 0x00000020 |
51 | #define PTRACE_O_TRACEEXIT 0x00000040 | |
3993f6b1 DJ |
52 | |
53 | /* Wait extended result codes for the above trace options. */ | |
54 | #define PTRACE_EVENT_FORK 1 | |
55 | #define PTRACE_EVENT_VFORK 2 | |
56 | #define PTRACE_EVENT_CLONE 3 | |
57 | #define PTRACE_EVENT_EXEC 4 | |
9016a515 DJ |
58 | #define PTRACE_EVENT_VFORKDONE 5 |
59 | #define PTRACE_EVENT_EXIT 6 | |
3993f6b1 DJ |
60 | |
61 | #endif /* PTRACE_EVENT_FORK */ | |
62 | ||
63 | /* We can't always assume that this flag is available, but all systems | |
64 | with the ptrace event handlers also have __WALL, so it's safe to use | |
65 | here. */ | |
66 | #ifndef __WALL | |
67 | #define __WALL 0x40000000 /* Wait for any child. */ | |
68 | #endif | |
69 | ||
d6b0e80f AC |
70 | static int debug_linux_nat; |
71 | ||
4de4c07c DJ |
72 | extern struct target_ops child_ops; |
73 | ||
9016a515 DJ |
74 | static int linux_parent_pid; |
75 | ||
ae087d01 DJ |
76 | struct simple_pid_list |
77 | { | |
78 | int pid; | |
79 | struct simple_pid_list *next; | |
80 | }; | |
81 | struct simple_pid_list *stopped_pids; | |
82 | ||
3993f6b1 DJ |
83 | /* This variable is a tri-state flag: -1 for unknown, 0 if PTRACE_O_TRACEFORK |
84 | can not be used, 1 if it can. */ | |
85 | ||
86 | static int linux_supports_tracefork_flag = -1; | |
87 | ||
9016a515 DJ |
88 | /* If we have PTRACE_O_TRACEFORK, this flag indicates whether we also have |
89 | PTRACE_O_TRACEVFORKDONE. */ | |
90 | ||
91 | static int linux_supports_tracevforkdone_flag = -1; | |
92 | ||
ae087d01 DJ |
93 | \f |
94 | /* Trivial list manipulation functions to keep track of a list of | |
95 | new stopped processes. */ | |
96 | static void | |
97 | add_to_pid_list (struct simple_pid_list **listp, int pid) | |
98 | { | |
99 | struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list)); | |
100 | new_pid->pid = pid; | |
101 | new_pid->next = *listp; | |
102 | *listp = new_pid; | |
103 | } | |
104 | ||
105 | static int | |
106 | pull_pid_from_list (struct simple_pid_list **listp, int pid) | |
107 | { | |
108 | struct simple_pid_list **p; | |
109 | ||
110 | for (p = listp; *p != NULL; p = &(*p)->next) | |
111 | if ((*p)->pid == pid) | |
112 | { | |
113 | struct simple_pid_list *next = (*p)->next; | |
114 | xfree (*p); | |
115 | *p = next; | |
116 | return 1; | |
117 | } | |
118 | return 0; | |
119 | } | |
120 | ||
121 | void | |
122 | linux_record_stopped_pid (int pid) | |
123 | { | |
124 | add_to_pid_list (&stopped_pids, pid); | |
125 | } | |
126 | ||
3993f6b1 DJ |
127 | \f |
128 | /* A helper function for linux_test_for_tracefork, called after fork (). */ | |
129 | ||
130 | static void | |
131 | linux_tracefork_child (void) | |
132 | { | |
133 | int ret; | |
134 | ||
135 | ptrace (PTRACE_TRACEME, 0, 0, 0); | |
136 | kill (getpid (), SIGSTOP); | |
137 | fork (); | |
138 | exit (0); | |
139 | } | |
140 | ||
141 | /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. We | |
142 | create a child process, attach to it, use PTRACE_SETOPTIONS to enable | |
143 | fork tracing, and let it fork. If the process exits, we assume that | |
144 | we can't use TRACEFORK; if we get the fork notification, and we can | |
145 | extract the new child's PID, then we assume that we can. */ | |
146 | ||
147 | static void | |
148 | linux_test_for_tracefork (void) | |
149 | { | |
150 | int child_pid, ret, status; | |
151 | long second_pid; | |
152 | ||
153 | child_pid = fork (); | |
154 | if (child_pid == -1) | |
155 | perror_with_name ("linux_test_for_tracefork: fork"); | |
156 | ||
157 | if (child_pid == 0) | |
158 | linux_tracefork_child (); | |
159 | ||
160 | ret = waitpid (child_pid, &status, 0); | |
161 | if (ret == -1) | |
162 | perror_with_name ("linux_test_for_tracefork: waitpid"); | |
163 | else if (ret != child_pid) | |
164 | error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret); | |
165 | if (! WIFSTOPPED (status)) | |
166 | error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status); | |
167 | ||
168 | linux_supports_tracefork_flag = 0; | |
169 | ||
170 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK); | |
171 | if (ret != 0) | |
172 | { | |
173 | ptrace (PTRACE_KILL, child_pid, 0, 0); | |
174 | waitpid (child_pid, &status, 0); | |
175 | return; | |
176 | } | |
177 | ||
9016a515 DJ |
178 | /* Check whether PTRACE_O_TRACEVFORKDONE is available. */ |
179 | ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, | |
180 | PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORKDONE); | |
181 | linux_supports_tracevforkdone_flag = (ret == 0); | |
182 | ||
3993f6b1 DJ |
183 | ptrace (PTRACE_CONT, child_pid, 0, 0); |
184 | ret = waitpid (child_pid, &status, 0); | |
185 | if (ret == child_pid && WIFSTOPPED (status) | |
186 | && status >> 16 == PTRACE_EVENT_FORK) | |
187 | { | |
188 | second_pid = 0; | |
189 | ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid); | |
190 | if (ret == 0 && second_pid != 0) | |
191 | { | |
192 | int second_status; | |
193 | ||
194 | linux_supports_tracefork_flag = 1; | |
195 | waitpid (second_pid, &second_status, 0); | |
196 | ptrace (PTRACE_DETACH, second_pid, 0, 0); | |
197 | } | |
198 | } | |
199 | ||
200 | if (WIFSTOPPED (status)) | |
201 | { | |
202 | ptrace (PTRACE_DETACH, child_pid, 0, 0); | |
203 | waitpid (child_pid, &status, 0); | |
204 | } | |
205 | } | |
206 | ||
207 | /* Return non-zero iff we have tracefork functionality available. | |
208 | This function also sets linux_supports_tracefork_flag. */ | |
209 | ||
210 | static int | |
211 | linux_supports_tracefork (void) | |
212 | { | |
213 | if (linux_supports_tracefork_flag == -1) | |
214 | linux_test_for_tracefork (); | |
215 | return linux_supports_tracefork_flag; | |
216 | } | |
217 | ||
9016a515 DJ |
218 | static int |
219 | linux_supports_tracevforkdone (void) | |
220 | { | |
221 | if (linux_supports_tracefork_flag == -1) | |
222 | linux_test_for_tracefork (); | |
223 | return linux_supports_tracevforkdone_flag; | |
224 | } | |
225 | ||
3993f6b1 | 226 | \f |
4de4c07c DJ |
227 | void |
228 | linux_enable_event_reporting (ptid_t ptid) | |
229 | { | |
230 | int pid = ptid_get_pid (ptid); | |
231 | int options; | |
232 | ||
233 | if (! linux_supports_tracefork ()) | |
234 | return; | |
235 | ||
a2f23071 DJ |
236 | options = PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK | PTRACE_O_TRACEEXEC |
237 | | PTRACE_O_TRACECLONE; | |
9016a515 DJ |
238 | if (linux_supports_tracevforkdone ()) |
239 | options |= PTRACE_O_TRACEVFORKDONE; | |
240 | ||
241 | /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to support | |
242 | read-only process state. */ | |
4de4c07c DJ |
243 | |
244 | ptrace (PTRACE_SETOPTIONS, pid, 0, options); | |
245 | } | |
246 | ||
247 | void | |
248 | child_post_attach (int pid) | |
249 | { | |
250 | linux_enable_event_reporting (pid_to_ptid (pid)); | |
251 | } | |
252 | ||
253 | void | |
254 | linux_child_post_startup_inferior (ptid_t ptid) | |
255 | { | |
256 | linux_enable_event_reporting (ptid); | |
257 | } | |
258 | ||
259 | #ifndef LINUX_CHILD_POST_STARTUP_INFERIOR | |
260 | void | |
261 | child_post_startup_inferior (ptid_t ptid) | |
262 | { | |
263 | linux_child_post_startup_inferior (ptid); | |
264 | } | |
265 | #endif | |
266 | ||
3993f6b1 | 267 | int |
4de4c07c | 268 | child_follow_fork (int follow_child) |
3993f6b1 | 269 | { |
4de4c07c DJ |
270 | ptid_t last_ptid; |
271 | struct target_waitstatus last_status; | |
9016a515 | 272 | int has_vforked; |
4de4c07c DJ |
273 | int parent_pid, child_pid; |
274 | ||
275 | get_last_target_status (&last_ptid, &last_status); | |
9016a515 | 276 | has_vforked = (last_status.kind == TARGET_WAITKIND_VFORKED); |
4de4c07c DJ |
277 | parent_pid = ptid_get_pid (last_ptid); |
278 | child_pid = last_status.value.related_pid; | |
279 | ||
280 | if (! follow_child) | |
281 | { | |
282 | /* We're already attached to the parent, by default. */ | |
283 | ||
284 | /* Before detaching from the child, remove all breakpoints from | |
285 | it. (This won't actually modify the breakpoint list, but will | |
286 | physically remove the breakpoints from the child.) */ | |
9016a515 DJ |
287 | /* If we vforked this will remove the breakpoints from the parent |
288 | also, but they'll be reinserted below. */ | |
4de4c07c DJ |
289 | detach_breakpoints (child_pid); |
290 | ||
291 | fprintf_filtered (gdb_stdout, | |
292 | "Detaching after fork from child process %d.\n", | |
293 | child_pid); | |
294 | ||
295 | ptrace (PTRACE_DETACH, child_pid, 0, 0); | |
9016a515 DJ |
296 | |
297 | if (has_vforked) | |
298 | { | |
299 | if (linux_supports_tracevforkdone ()) | |
300 | { | |
301 | int status; | |
302 | ||
303 | ptrace (PTRACE_CONT, parent_pid, 0, 0); | |
304 | waitpid (parent_pid, &status, __WALL); | |
305 | if ((status >> 16) != PTRACE_EVENT_VFORKDONE) | |
306 | warning ("Unexpected waitpid result %06x when waiting for " | |
307 | "vfork-done", status); | |
308 | } | |
309 | else | |
310 | { | |
311 | /* We can't insert breakpoints until the child has | |
312 | finished with the shared memory region. We need to | |
313 | wait until that happens. Ideal would be to just | |
314 | call: | |
315 | - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0); | |
316 | - waitpid (parent_pid, &status, __WALL); | |
317 | However, most architectures can't handle a syscall | |
318 | being traced on the way out if it wasn't traced on | |
319 | the way in. | |
320 | ||
321 | We might also think to loop, continuing the child | |
322 | until it exits or gets a SIGTRAP. One problem is | |
323 | that the child might call ptrace with PTRACE_TRACEME. | |
324 | ||
325 | There's no simple and reliable way to figure out when | |
326 | the vforked child will be done with its copy of the | |
327 | shared memory. We could step it out of the syscall, | |
328 | two instructions, let it go, and then single-step the | |
329 | parent once. When we have hardware single-step, this | |
330 | would work; with software single-step it could still | |
331 | be made to work but we'd have to be able to insert | |
332 | single-step breakpoints in the child, and we'd have | |
333 | to insert -just- the single-step breakpoint in the | |
334 | parent. Very awkward. | |
335 | ||
336 | In the end, the best we can do is to make sure it | |
337 | runs for a little while. Hopefully it will be out of | |
338 | range of any breakpoints we reinsert. Usually this | |
339 | is only the single-step breakpoint at vfork's return | |
340 | point. */ | |
341 | ||
342 | usleep (10000); | |
343 | } | |
344 | ||
345 | /* Since we vforked, breakpoints were removed in the parent | |
346 | too. Put them back. */ | |
347 | reattach_breakpoints (parent_pid); | |
348 | } | |
4de4c07c | 349 | } |
3993f6b1 | 350 | else |
4de4c07c DJ |
351 | { |
352 | char child_pid_spelling[40]; | |
353 | ||
354 | /* Needed to keep the breakpoint lists in sync. */ | |
9016a515 DJ |
355 | if (! has_vforked) |
356 | detach_breakpoints (child_pid); | |
4de4c07c DJ |
357 | |
358 | /* Before detaching from the parent, remove all breakpoints from it. */ | |
359 | remove_breakpoints (); | |
360 | ||
361 | fprintf_filtered (gdb_stdout, | |
362 | "Attaching after fork to child process %d.\n", | |
363 | child_pid); | |
364 | ||
9016a515 DJ |
365 | /* If we're vforking, we may want to hold on to the parent until |
366 | the child exits or execs. At exec time we can remove the old | |
367 | breakpoints from the parent and detach it; at exit time we | |
368 | could do the same (or even, sneakily, resume debugging it - the | |
369 | child's exec has failed, or something similar). | |
370 | ||
371 | This doesn't clean up "properly", because we can't call | |
372 | target_detach, but that's OK; if the current target is "child", | |
373 | then it doesn't need any further cleanups, and lin_lwp will | |
374 | generally not encounter vfork (vfork is defined to fork | |
375 | in libpthread.so). | |
376 | ||
377 | The holding part is very easy if we have VFORKDONE events; | |
378 | but keeping track of both processes is beyond GDB at the | |
379 | moment. So we don't expose the parent to the rest of GDB. | |
380 | Instead we quietly hold onto it until such time as we can | |
381 | safely resume it. */ | |
382 | ||
383 | if (has_vforked) | |
384 | linux_parent_pid = parent_pid; | |
385 | else | |
386 | target_detach (NULL, 0); | |
4de4c07c DJ |
387 | |
388 | inferior_ptid = pid_to_ptid (child_pid); | |
389 | push_target (&child_ops); | |
390 | ||
391 | /* Reset breakpoints in the child as appropriate. */ | |
392 | follow_inferior_reset_breakpoints (); | |
393 | } | |
394 | ||
395 | return 0; | |
396 | } | |
397 | ||
398 | ptid_t | |
399 | linux_handle_extended_wait (int pid, int status, | |
400 | struct target_waitstatus *ourstatus) | |
401 | { | |
402 | int event = status >> 16; | |
403 | ||
a2f23071 DJ |
404 | if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK |
405 | || event == PTRACE_EVENT_CLONE) | |
4de4c07c DJ |
406 | { |
407 | unsigned long new_pid; | |
408 | int ret; | |
409 | ||
410 | ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid); | |
411 | ||
412 | /* If we haven't already seen the new PID stop, wait for it now. */ | |
413 | if (! pull_pid_from_list (&stopped_pids, new_pid)) | |
414 | { | |
415 | /* The new child has a pending SIGSTOP. We can't affect it until it | |
a2f23071 | 416 | hits the SIGSTOP, but we're already attached. */ |
4de4c07c | 417 | do { |
a2f23071 DJ |
418 | ret = waitpid (new_pid, &status, |
419 | (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0); | |
4de4c07c DJ |
420 | } while (ret == -1 && errno == EINTR); |
421 | if (ret == -1) | |
422 | perror_with_name ("waiting for new child"); | |
423 | else if (ret != new_pid) | |
424 | internal_error (__FILE__, __LINE__, | |
425 | "wait returned unexpected PID %d", ret); | |
426 | else if (!WIFSTOPPED (status) || WSTOPSIG (status) != SIGSTOP) | |
427 | internal_error (__FILE__, __LINE__, | |
428 | "wait returned unexpected status 0x%x", status); | |
429 | } | |
430 | ||
a2f23071 DJ |
431 | if (event == PTRACE_EVENT_FORK) |
432 | ourstatus->kind = TARGET_WAITKIND_FORKED; | |
433 | else if (event == PTRACE_EVENT_VFORK) | |
434 | ourstatus->kind = TARGET_WAITKIND_VFORKED; | |
435 | else | |
436 | ourstatus->kind = TARGET_WAITKIND_SPURIOUS; | |
437 | ||
4de4c07c DJ |
438 | ourstatus->value.related_pid = new_pid; |
439 | return inferior_ptid; | |
440 | } | |
441 | ||
9016a515 DJ |
442 | if (event == PTRACE_EVENT_EXEC) |
443 | { | |
444 | ourstatus->kind = TARGET_WAITKIND_EXECD; | |
445 | ourstatus->value.execd_pathname | |
446 | = xstrdup (child_pid_to_exec_file (pid)); | |
447 | ||
448 | if (linux_parent_pid) | |
449 | { | |
450 | detach_breakpoints (linux_parent_pid); | |
451 | ptrace (PTRACE_DETACH, linux_parent_pid, 0, 0); | |
452 | ||
453 | linux_parent_pid = 0; | |
454 | } | |
455 | ||
456 | return inferior_ptid; | |
457 | } | |
458 | ||
4de4c07c DJ |
459 | internal_error (__FILE__, __LINE__, |
460 | "unknown ptrace event %d", event); | |
461 | } | |
462 | ||
463 | \f | |
464 | int | |
465 | child_insert_fork_catchpoint (int pid) | |
466 | { | |
467 | if (! linux_supports_tracefork ()) | |
3993f6b1 | 468 | error ("Your system does not support fork catchpoints."); |
4de4c07c DJ |
469 | |
470 | return 0; | |
3993f6b1 DJ |
471 | } |
472 | ||
473 | int | |
474 | child_insert_vfork_catchpoint (int pid) | |
475 | { | |
9016a515 | 476 | if (!linux_supports_tracefork ()) |
3993f6b1 | 477 | error ("Your system does not support vfork catchpoints."); |
9016a515 DJ |
478 | |
479 | return 0; | |
3993f6b1 DJ |
480 | } |
481 | ||
482 | int | |
483 | child_insert_exec_catchpoint (int pid) | |
484 | { | |
9016a515 | 485 | if (!linux_supports_tracefork ()) |
3993f6b1 | 486 | error ("Your system does not support exec catchpoints."); |
9016a515 DJ |
487 | |
488 | return 0; | |
3993f6b1 DJ |
489 | } |
490 | ||
4de4c07c DJ |
491 | void |
492 | kill_inferior (void) | |
493 | { | |
494 | int status; | |
495 | int pid = PIDGET (inferior_ptid); | |
496 | struct target_waitstatus last; | |
497 | ptid_t last_ptid; | |
498 | int ret; | |
499 | ||
500 | if (pid == 0) | |
501 | return; | |
502 | ||
503 | /* If we're stopped while forking and we haven't followed yet, kill the | |
504 | other task. We need to do this first because the parent will be | |
505 | sleeping if this is a vfork. */ | |
506 | ||
507 | get_last_target_status (&last_ptid, &last); | |
3993f6b1 | 508 | |
4de4c07c DJ |
509 | if (last.kind == TARGET_WAITKIND_FORKED |
510 | || last.kind == TARGET_WAITKIND_VFORKED) | |
511 | { | |
de9a9e51 | 512 | ptrace (PT_KILL, last.value.related_pid, 0, 0); |
4de4c07c DJ |
513 | ptrace_wait (null_ptid, &status); |
514 | } | |
515 | ||
516 | /* Kill the current process. */ | |
de9a9e51 | 517 | ptrace (PT_KILL, pid, 0, 0); |
4de4c07c DJ |
518 | ret = ptrace_wait (null_ptid, &status); |
519 | ||
520 | /* We might get a SIGCHLD instead of an exit status. This is | |
521 | aggravated by the first kill above - a child has just died. */ | |
522 | ||
523 | while (ret == pid && WIFSTOPPED (status)) | |
524 | { | |
de9a9e51 | 525 | ptrace (PT_KILL, pid, 0, 0); |
4de4c07c DJ |
526 | ret = ptrace_wait (null_ptid, &status); |
527 | } | |
528 | ||
529 | target_mourn_inferior (); | |
530 | } | |
d6b0e80f AC |
531 | |
532 | /* On GNU/Linux there are no real LWP's. The closest thing to LWP's | |
533 | are processes sharing the same VM space. A multi-threaded process | |
534 | is basically a group of such processes. However, such a grouping | |
535 | is almost entirely a user-space issue; the kernel doesn't enforce | |
536 | such a grouping at all (this might change in the future). In | |
537 | general, we'll rely on the threads library (i.e. the GNU/Linux | |
538 | Threads library) to provide such a grouping. | |
539 | ||
540 | It is perfectly well possible to write a multi-threaded application | |
541 | without the assistance of a threads library, by using the clone | |
542 | system call directly. This module should be able to give some | |
543 | rudimentary support for debugging such applications if developers | |
544 | specify the CLONE_PTRACE flag in the clone system call, and are | |
545 | using the Linux kernel 2.4 or above. | |
546 | ||
547 | Note that there are some peculiarities in GNU/Linux that affect | |
548 | this code: | |
549 | ||
550 | - In general one should specify the __WCLONE flag to waitpid in | |
551 | order to make it report events for any of the cloned processes | |
552 | (and leave it out for the initial process). However, if a cloned | |
553 | process has exited the exit status is only reported if the | |
554 | __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but | |
555 | we cannot use it since GDB must work on older systems too. | |
556 | ||
557 | - When a traced, cloned process exits and is waited for by the | |
558 | debugger, the kernel reassigns it to the original parent and | |
559 | keeps it around as a "zombie". Somehow, the GNU/Linux Threads | |
560 | library doesn't notice this, which leads to the "zombie problem": | |
561 | When debugged a multi-threaded process that spawns a lot of | |
562 | threads will run out of processes, even if the threads exit, | |
563 | because the "zombies" stay around. */ | |
564 | ||
565 | /* List of known LWPs. */ | |
566 | static struct lwp_info *lwp_list; | |
567 | ||
568 | /* Number of LWPs in the list. */ | |
569 | static int num_lwps; | |
570 | ||
571 | /* Non-zero if we're running in "threaded" mode. */ | |
572 | static int threaded; | |
573 | \f | |
574 | ||
575 | #define GET_LWP(ptid) ptid_get_lwp (ptid) | |
576 | #define GET_PID(ptid) ptid_get_pid (ptid) | |
577 | #define is_lwp(ptid) (GET_LWP (ptid) != 0) | |
578 | #define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0) | |
579 | ||
580 | /* If the last reported event was a SIGTRAP, this variable is set to | |
581 | the process id of the LWP/thread that got it. */ | |
582 | ptid_t trap_ptid; | |
583 | \f | |
584 | ||
585 | /* This module's target-specific operations. */ | |
586 | static struct target_ops linux_nat_ops; | |
587 | ||
588 | /* The standard child operations. */ | |
589 | extern struct target_ops child_ops; | |
590 | ||
591 | /* Since we cannot wait (in linux_nat_wait) for the initial process and | |
592 | any cloned processes with a single call to waitpid, we have to use | |
593 | the WNOHANG flag and call waitpid in a loop. To optimize | |
594 | things a bit we use `sigsuspend' to wake us up when a process has | |
595 | something to report (it will send us a SIGCHLD if it has). To make | |
596 | this work we have to juggle with the signal mask. We save the | |
597 | original signal mask such that we can restore it before creating a | |
598 | new process in order to avoid blocking certain signals in the | |
599 | inferior. We then block SIGCHLD during the waitpid/sigsuspend | |
600 | loop. */ | |
601 | ||
602 | /* Original signal mask. */ | |
603 | static sigset_t normal_mask; | |
604 | ||
605 | /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in | |
606 | _initialize_linux_nat. */ | |
607 | static sigset_t suspend_mask; | |
608 | ||
609 | /* Signals to block to make that sigsuspend work. */ | |
610 | static sigset_t blocked_mask; | |
611 | \f | |
612 | ||
613 | /* Prototypes for local functions. */ | |
614 | static int stop_wait_callback (struct lwp_info *lp, void *data); | |
615 | static int linux_nat_thread_alive (ptid_t ptid); | |
616 | \f | |
617 | /* Convert wait status STATUS to a string. Used for printing debug | |
618 | messages only. */ | |
619 | ||
620 | static char * | |
621 | status_to_str (int status) | |
622 | { | |
623 | static char buf[64]; | |
624 | ||
625 | if (WIFSTOPPED (status)) | |
626 | snprintf (buf, sizeof (buf), "%s (stopped)", | |
627 | strsignal (WSTOPSIG (status))); | |
628 | else if (WIFSIGNALED (status)) | |
629 | snprintf (buf, sizeof (buf), "%s (terminated)", | |
630 | strsignal (WSTOPSIG (status))); | |
631 | else | |
632 | snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status)); | |
633 | ||
634 | return buf; | |
635 | } | |
636 | ||
637 | /* Initialize the list of LWPs. Note that this module, contrary to | |
638 | what GDB's generic threads layer does for its thread list, | |
639 | re-initializes the LWP lists whenever we mourn or detach (which | |
640 | doesn't involve mourning) the inferior. */ | |
641 | ||
642 | static void | |
643 | init_lwp_list (void) | |
644 | { | |
645 | struct lwp_info *lp, *lpnext; | |
646 | ||
647 | for (lp = lwp_list; lp; lp = lpnext) | |
648 | { | |
649 | lpnext = lp->next; | |
650 | xfree (lp); | |
651 | } | |
652 | ||
653 | lwp_list = NULL; | |
654 | num_lwps = 0; | |
655 | threaded = 0; | |
656 | } | |
657 | ||
658 | /* Add the LWP specified by PID to the list. If this causes the | |
659 | number of LWPs to become larger than one, go into "threaded" mode. | |
660 | Return a pointer to the structure describing the new LWP. */ | |
661 | ||
662 | static struct lwp_info * | |
663 | add_lwp (ptid_t ptid) | |
664 | { | |
665 | struct lwp_info *lp; | |
666 | ||
667 | gdb_assert (is_lwp (ptid)); | |
668 | ||
669 | lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info)); | |
670 | ||
671 | memset (lp, 0, sizeof (struct lwp_info)); | |
672 | ||
673 | lp->waitstatus.kind = TARGET_WAITKIND_IGNORE; | |
674 | ||
675 | lp->ptid = ptid; | |
676 | ||
677 | lp->next = lwp_list; | |
678 | lwp_list = lp; | |
679 | if (++num_lwps > 1) | |
680 | threaded = 1; | |
681 | ||
682 | return lp; | |
683 | } | |
684 | ||
685 | /* Remove the LWP specified by PID from the list. */ | |
686 | ||
687 | static void | |
688 | delete_lwp (ptid_t ptid) | |
689 | { | |
690 | struct lwp_info *lp, *lpprev; | |
691 | ||
692 | lpprev = NULL; | |
693 | ||
694 | for (lp = lwp_list; lp; lpprev = lp, lp = lp->next) | |
695 | if (ptid_equal (lp->ptid, ptid)) | |
696 | break; | |
697 | ||
698 | if (!lp) | |
699 | return; | |
700 | ||
701 | /* We don't go back to "non-threaded" mode if the number of threads | |
702 | becomes less than two. */ | |
703 | num_lwps--; | |
704 | ||
705 | if (lpprev) | |
706 | lpprev->next = lp->next; | |
707 | else | |
708 | lwp_list = lp->next; | |
709 | ||
710 | xfree (lp); | |
711 | } | |
712 | ||
713 | /* Return a pointer to the structure describing the LWP corresponding | |
714 | to PID. If no corresponding LWP could be found, return NULL. */ | |
715 | ||
716 | static struct lwp_info * | |
717 | find_lwp_pid (ptid_t ptid) | |
718 | { | |
719 | struct lwp_info *lp; | |
720 | int lwp; | |
721 | ||
722 | if (is_lwp (ptid)) | |
723 | lwp = GET_LWP (ptid); | |
724 | else | |
725 | lwp = GET_PID (ptid); | |
726 | ||
727 | for (lp = lwp_list; lp; lp = lp->next) | |
728 | if (lwp == GET_LWP (lp->ptid)) | |
729 | return lp; | |
730 | ||
731 | return NULL; | |
732 | } | |
733 | ||
734 | /* Call CALLBACK with its second argument set to DATA for every LWP in | |
735 | the list. If CALLBACK returns 1 for a particular LWP, return a | |
736 | pointer to the structure describing that LWP immediately. | |
737 | Otherwise return NULL. */ | |
738 | ||
739 | struct lwp_info * | |
740 | iterate_over_lwps (int (*callback) (struct lwp_info *, void *), void *data) | |
741 | { | |
742 | struct lwp_info *lp, *lpnext; | |
743 | ||
744 | for (lp = lwp_list; lp; lp = lpnext) | |
745 | { | |
746 | lpnext = lp->next; | |
747 | if ((*callback) (lp, data)) | |
748 | return lp; | |
749 | } | |
750 | ||
751 | return NULL; | |
752 | } | |
753 | ||
754 | /* Attach to the LWP specified by PID. If VERBOSE is non-zero, print | |
755 | a message telling the user that a new LWP has been added to the | |
756 | process. */ | |
757 | ||
758 | void | |
759 | lin_lwp_attach_lwp (ptid_t ptid, int verbose) | |
760 | { | |
761 | struct lwp_info *lp, *found_lp; | |
762 | ||
763 | gdb_assert (is_lwp (ptid)); | |
764 | ||
765 | /* Make sure SIGCHLD is blocked. We don't want SIGCHLD events | |
766 | to interrupt either the ptrace() or waitpid() calls below. */ | |
767 | if (!sigismember (&blocked_mask, SIGCHLD)) | |
768 | { | |
769 | sigaddset (&blocked_mask, SIGCHLD); | |
770 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
771 | } | |
772 | ||
773 | if (verbose) | |
774 | printf_filtered ("[New %s]\n", target_pid_to_str (ptid)); | |
775 | ||
776 | found_lp = lp = find_lwp_pid (ptid); | |
777 | if (lp == NULL) | |
778 | lp = add_lwp (ptid); | |
779 | ||
780 | /* We assume that we're already attached to any LWP that has an id | |
781 | equal to the overall process id, and to any LWP that is already | |
782 | in our list of LWPs. If we're not seeing exit events from threads | |
783 | and we've had PID wraparound since we last tried to stop all threads, | |
784 | this assumption might be wrong; fortunately, this is very unlikely | |
785 | to happen. */ | |
786 | if (GET_LWP (ptid) != GET_PID (ptid) && found_lp == NULL) | |
787 | { | |
788 | pid_t pid; | |
789 | int status; | |
790 | ||
791 | if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0) | |
792 | error ("Can't attach %s: %s", target_pid_to_str (ptid), | |
793 | safe_strerror (errno)); | |
794 | ||
795 | if (debug_linux_nat) | |
796 | fprintf_unfiltered (gdb_stdlog, | |
797 | "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n", | |
798 | target_pid_to_str (ptid)); | |
799 | ||
800 | pid = waitpid (GET_LWP (ptid), &status, 0); | |
801 | if (pid == -1 && errno == ECHILD) | |
802 | { | |
803 | /* Try again with __WCLONE to check cloned processes. */ | |
804 | pid = waitpid (GET_LWP (ptid), &status, __WCLONE); | |
805 | lp->cloned = 1; | |
806 | } | |
807 | ||
808 | gdb_assert (pid == GET_LWP (ptid) | |
809 | && WIFSTOPPED (status) && WSTOPSIG (status)); | |
810 | ||
811 | child_post_attach (pid); | |
812 | ||
813 | lp->stopped = 1; | |
814 | ||
815 | if (debug_linux_nat) | |
816 | { | |
817 | fprintf_unfiltered (gdb_stdlog, | |
818 | "LLAL: waitpid %s received %s\n", | |
819 | target_pid_to_str (ptid), | |
820 | status_to_str (status)); | |
821 | } | |
822 | } | |
823 | else | |
824 | { | |
825 | /* We assume that the LWP representing the original process is | |
826 | already stopped. Mark it as stopped in the data structure | |
827 | that the linux ptrace layer uses to keep track of threads. | |
828 | Note that this won't have already been done since the main | |
829 | thread will have, we assume, been stopped by an attach from a | |
830 | different layer. */ | |
831 | lp->stopped = 1; | |
832 | } | |
833 | } | |
834 | ||
835 | static void | |
836 | linux_nat_attach (char *args, int from_tty) | |
837 | { | |
838 | struct lwp_info *lp; | |
839 | pid_t pid; | |
840 | int status; | |
841 | ||
842 | /* FIXME: We should probably accept a list of process id's, and | |
843 | attach all of them. */ | |
844 | child_ops.to_attach (args, from_tty); | |
845 | ||
846 | /* Add the initial process as the first LWP to the list. */ | |
847 | lp = add_lwp (BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid))); | |
848 | ||
849 | /* Make sure the initial process is stopped. The user-level threads | |
850 | layer might want to poke around in the inferior, and that won't | |
851 | work if things haven't stabilized yet. */ | |
852 | pid = waitpid (GET_PID (inferior_ptid), &status, 0); | |
853 | if (pid == -1 && errno == ECHILD) | |
854 | { | |
855 | warning ("%s is a cloned process", target_pid_to_str (inferior_ptid)); | |
856 | ||
857 | /* Try again with __WCLONE to check cloned processes. */ | |
858 | pid = waitpid (GET_PID (inferior_ptid), &status, __WCLONE); | |
859 | lp->cloned = 1; | |
860 | } | |
861 | ||
862 | gdb_assert (pid == GET_PID (inferior_ptid) | |
863 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP); | |
864 | ||
865 | lp->stopped = 1; | |
866 | ||
867 | /* Fake the SIGSTOP that core GDB expects. */ | |
868 | lp->status = W_STOPCODE (SIGSTOP); | |
869 | lp->resumed = 1; | |
870 | if (debug_linux_nat) | |
871 | { | |
872 | fprintf_unfiltered (gdb_stdlog, | |
873 | "LLA: waitpid %ld, faking SIGSTOP\n", (long) pid); | |
874 | } | |
875 | } | |
876 | ||
877 | static int | |
878 | detach_callback (struct lwp_info *lp, void *data) | |
879 | { | |
880 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); | |
881 | ||
882 | if (debug_linux_nat && lp->status) | |
883 | fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n", | |
884 | strsignal (WSTOPSIG (lp->status)), | |
885 | target_pid_to_str (lp->ptid)); | |
886 | ||
887 | while (lp->signalled && lp->stopped) | |
888 | { | |
889 | errno = 0; | |
890 | if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, | |
891 | WSTOPSIG (lp->status)) < 0) | |
892 | error ("Can't continue %s: %s", target_pid_to_str (lp->ptid), | |
893 | safe_strerror (errno)); | |
894 | ||
895 | if (debug_linux_nat) | |
896 | fprintf_unfiltered (gdb_stdlog, | |
897 | "DC: PTRACE_CONTINUE (%s, 0, %s) (OK)\n", | |
898 | target_pid_to_str (lp->ptid), | |
899 | status_to_str (lp->status)); | |
900 | ||
901 | lp->stopped = 0; | |
902 | lp->signalled = 0; | |
903 | lp->status = 0; | |
904 | /* FIXME drow/2003-08-26: There was a call to stop_wait_callback | |
905 | here. But since lp->signalled was cleared above, | |
906 | stop_wait_callback didn't do anything; the process was left | |
907 | running. Shouldn't we be waiting for it to stop? | |
908 | I've removed the call, since stop_wait_callback now does do | |
909 | something when called with lp->signalled == 0. */ | |
910 | ||
911 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); | |
912 | } | |
913 | ||
914 | /* We don't actually detach from the LWP that has an id equal to the | |
915 | overall process id just yet. */ | |
916 | if (GET_LWP (lp->ptid) != GET_PID (lp->ptid)) | |
917 | { | |
918 | errno = 0; | |
919 | if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0, | |
920 | WSTOPSIG (lp->status)) < 0) | |
921 | error ("Can't detach %s: %s", target_pid_to_str (lp->ptid), | |
922 | safe_strerror (errno)); | |
923 | ||
924 | if (debug_linux_nat) | |
925 | fprintf_unfiltered (gdb_stdlog, | |
926 | "PTRACE_DETACH (%s, %s, 0) (OK)\n", | |
927 | target_pid_to_str (lp->ptid), | |
928 | strsignal (WSTOPSIG (lp->status))); | |
929 | ||
930 | delete_lwp (lp->ptid); | |
931 | } | |
932 | ||
933 | return 0; | |
934 | } | |
935 | ||
936 | static void | |
937 | linux_nat_detach (char *args, int from_tty) | |
938 | { | |
939 | iterate_over_lwps (detach_callback, NULL); | |
940 | ||
941 | /* Only the initial process should be left right now. */ | |
942 | gdb_assert (num_lwps == 1); | |
943 | ||
944 | trap_ptid = null_ptid; | |
945 | ||
946 | /* Destroy LWP info; it's no longer valid. */ | |
947 | init_lwp_list (); | |
948 | ||
949 | /* Restore the original signal mask. */ | |
950 | sigprocmask (SIG_SETMASK, &normal_mask, NULL); | |
951 | sigemptyset (&blocked_mask); | |
952 | ||
953 | inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid)); | |
954 | child_ops.to_detach (args, from_tty); | |
955 | } | |
956 | ||
957 | /* Resume LP. */ | |
958 | ||
959 | static int | |
960 | resume_callback (struct lwp_info *lp, void *data) | |
961 | { | |
962 | if (lp->stopped && lp->status == 0) | |
963 | { | |
964 | struct thread_info *tp; | |
965 | ||
966 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0); | |
967 | if (debug_linux_nat) | |
968 | fprintf_unfiltered (gdb_stdlog, | |
969 | "RC: PTRACE_CONT %s, 0, 0 (resume sibling)\n", | |
970 | target_pid_to_str (lp->ptid)); | |
971 | lp->stopped = 0; | |
972 | lp->step = 0; | |
973 | } | |
974 | ||
975 | return 0; | |
976 | } | |
977 | ||
978 | static int | |
979 | resume_clear_callback (struct lwp_info *lp, void *data) | |
980 | { | |
981 | lp->resumed = 0; | |
982 | return 0; | |
983 | } | |
984 | ||
985 | static int | |
986 | resume_set_callback (struct lwp_info *lp, void *data) | |
987 | { | |
988 | lp->resumed = 1; | |
989 | return 0; | |
990 | } | |
991 | ||
992 | static void | |
993 | linux_nat_resume (ptid_t ptid, int step, enum target_signal signo) | |
994 | { | |
995 | struct lwp_info *lp; | |
996 | int resume_all; | |
997 | ||
998 | /* A specific PTID means `step only this process id'. */ | |
999 | resume_all = (PIDGET (ptid) == -1); | |
1000 | ||
1001 | if (resume_all) | |
1002 | iterate_over_lwps (resume_set_callback, NULL); | |
1003 | else | |
1004 | iterate_over_lwps (resume_clear_callback, NULL); | |
1005 | ||
1006 | /* If PID is -1, it's the current inferior that should be | |
1007 | handled specially. */ | |
1008 | if (PIDGET (ptid) == -1) | |
1009 | ptid = inferior_ptid; | |
1010 | ||
1011 | lp = find_lwp_pid (ptid); | |
1012 | if (lp) | |
1013 | { | |
1014 | ptid = pid_to_ptid (GET_LWP (lp->ptid)); | |
1015 | ||
1016 | /* Remember if we're stepping. */ | |
1017 | lp->step = step; | |
1018 | ||
1019 | /* Mark this LWP as resumed. */ | |
1020 | lp->resumed = 1; | |
1021 | ||
1022 | /* If we have a pending wait status for this thread, there is no | |
1023 | point in resuming the process. */ | |
1024 | if (lp->status) | |
1025 | { | |
1026 | /* FIXME: What should we do if we are supposed to continue | |
1027 | this thread with a signal? */ | |
1028 | gdb_assert (signo == TARGET_SIGNAL_0); | |
1029 | return; | |
1030 | } | |
1031 | ||
1032 | /* Mark LWP as not stopped to prevent it from being continued by | |
1033 | resume_callback. */ | |
1034 | lp->stopped = 0; | |
1035 | } | |
1036 | ||
1037 | if (resume_all) | |
1038 | iterate_over_lwps (resume_callback, NULL); | |
1039 | ||
1040 | child_resume (ptid, step, signo); | |
1041 | if (debug_linux_nat) | |
1042 | fprintf_unfiltered (gdb_stdlog, | |
1043 | "LLR: %s %s, %s (resume event thread)\n", | |
1044 | step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT", | |
1045 | target_pid_to_str (ptid), | |
1046 | signo ? strsignal (signo) : "0"); | |
1047 | } | |
1048 | ||
1049 | /* Issue kill to specified lwp. */ | |
1050 | ||
1051 | static int tkill_failed; | |
1052 | ||
1053 | static int | |
1054 | kill_lwp (int lwpid, int signo) | |
1055 | { | |
1056 | errno = 0; | |
1057 | ||
1058 | /* Use tkill, if possible, in case we are using nptl threads. If tkill | |
1059 | fails, then we are not using nptl threads and we should be using kill. */ | |
1060 | ||
1061 | #ifdef HAVE_TKILL_SYSCALL | |
1062 | if (!tkill_failed) | |
1063 | { | |
1064 | int ret = syscall (__NR_tkill, lwpid, signo); | |
1065 | if (errno != ENOSYS) | |
1066 | return ret; | |
1067 | errno = 0; | |
1068 | tkill_failed = 1; | |
1069 | } | |
1070 | #endif | |
1071 | ||
1072 | return kill (lwpid, signo); | |
1073 | } | |
1074 | ||
1075 | /* Handle a GNU/Linux extended wait response. Most of the work we | |
1076 | just pass off to linux_handle_extended_wait, but if it reports a | |
1077 | clone event we need to add the new LWP to our list (and not report | |
1078 | the trap to higher layers). This function returns non-zero if | |
1079 | the event should be ignored and we should wait again. */ | |
1080 | ||
1081 | static int | |
1082 | linux_nat_handle_extended (struct lwp_info *lp, int status) | |
1083 | { | |
1084 | linux_handle_extended_wait (GET_LWP (lp->ptid), status, | |
1085 | &lp->waitstatus); | |
1086 | ||
1087 | /* TARGET_WAITKIND_SPURIOUS is used to indicate clone events. */ | |
1088 | if (lp->waitstatus.kind == TARGET_WAITKIND_SPURIOUS) | |
1089 | { | |
1090 | struct lwp_info *new_lp; | |
1091 | new_lp = add_lwp (BUILD_LWP (lp->waitstatus.value.related_pid, | |
1092 | GET_PID (inferior_ptid))); | |
1093 | new_lp->cloned = 1; | |
1094 | new_lp->stopped = 1; | |
1095 | ||
1096 | lp->waitstatus.kind = TARGET_WAITKIND_IGNORE; | |
1097 | ||
1098 | if (debug_linux_nat) | |
1099 | fprintf_unfiltered (gdb_stdlog, | |
1100 | "LLHE: Got clone event from LWP %ld, resuming\n", | |
1101 | GET_LWP (lp->ptid)); | |
1102 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
1103 | ||
1104 | return 1; | |
1105 | } | |
1106 | ||
1107 | return 0; | |
1108 | } | |
1109 | ||
1110 | /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has | |
1111 | exited. */ | |
1112 | ||
1113 | static int | |
1114 | wait_lwp (struct lwp_info *lp) | |
1115 | { | |
1116 | pid_t pid; | |
1117 | int status; | |
1118 | int thread_dead = 0; | |
1119 | ||
1120 | gdb_assert (!lp->stopped); | |
1121 | gdb_assert (lp->status == 0); | |
1122 | ||
1123 | pid = waitpid (GET_LWP (lp->ptid), &status, 0); | |
1124 | if (pid == -1 && errno == ECHILD) | |
1125 | { | |
1126 | pid = waitpid (GET_LWP (lp->ptid), &status, __WCLONE); | |
1127 | if (pid == -1 && errno == ECHILD) | |
1128 | { | |
1129 | /* The thread has previously exited. We need to delete it | |
1130 | now because, for some vendor 2.4 kernels with NPTL | |
1131 | support backported, there won't be an exit event unless | |
1132 | it is the main thread. 2.6 kernels will report an exit | |
1133 | event for each thread that exits, as expected. */ | |
1134 | thread_dead = 1; | |
1135 | if (debug_linux_nat) | |
1136 | fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n", | |
1137 | target_pid_to_str (lp->ptid)); | |
1138 | } | |
1139 | } | |
1140 | ||
1141 | if (!thread_dead) | |
1142 | { | |
1143 | gdb_assert (pid == GET_LWP (lp->ptid)); | |
1144 | ||
1145 | if (debug_linux_nat) | |
1146 | { | |
1147 | fprintf_unfiltered (gdb_stdlog, | |
1148 | "WL: waitpid %s received %s\n", | |
1149 | target_pid_to_str (lp->ptid), | |
1150 | status_to_str (status)); | |
1151 | } | |
1152 | } | |
1153 | ||
1154 | /* Check if the thread has exited. */ | |
1155 | if (WIFEXITED (status) || WIFSIGNALED (status)) | |
1156 | { | |
1157 | thread_dead = 1; | |
1158 | if (debug_linux_nat) | |
1159 | fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n", | |
1160 | target_pid_to_str (lp->ptid)); | |
1161 | } | |
1162 | ||
1163 | if (thread_dead) | |
1164 | { | |
1165 | if (in_thread_list (lp->ptid)) | |
1166 | { | |
1167 | /* Core GDB cannot deal with us deleting the current thread. */ | |
1168 | if (!ptid_equal (lp->ptid, inferior_ptid)) | |
1169 | delete_thread (lp->ptid); | |
1170 | printf_unfiltered ("[%s exited]\n", | |
1171 | target_pid_to_str (lp->ptid)); | |
1172 | } | |
1173 | ||
1174 | delete_lwp (lp->ptid); | |
1175 | return 0; | |
1176 | } | |
1177 | ||
1178 | gdb_assert (WIFSTOPPED (status)); | |
1179 | ||
1180 | /* Handle GNU/Linux's extended waitstatus for trace events. */ | |
1181 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0) | |
1182 | { | |
1183 | if (debug_linux_nat) | |
1184 | fprintf_unfiltered (gdb_stdlog, | |
1185 | "WL: Handling extended status 0x%06x\n", | |
1186 | status); | |
1187 | if (linux_nat_handle_extended (lp, status)) | |
1188 | return wait_lwp (lp); | |
1189 | } | |
1190 | ||
1191 | return status; | |
1192 | } | |
1193 | ||
1194 | /* Send a SIGSTOP to LP. */ | |
1195 | ||
1196 | static int | |
1197 | stop_callback (struct lwp_info *lp, void *data) | |
1198 | { | |
1199 | if (!lp->stopped && !lp->signalled) | |
1200 | { | |
1201 | int ret; | |
1202 | ||
1203 | if (debug_linux_nat) | |
1204 | { | |
1205 | fprintf_unfiltered (gdb_stdlog, | |
1206 | "SC: kill %s **<SIGSTOP>**\n", | |
1207 | target_pid_to_str (lp->ptid)); | |
1208 | } | |
1209 | errno = 0; | |
1210 | ret = kill_lwp (GET_LWP (lp->ptid), SIGSTOP); | |
1211 | if (debug_linux_nat) | |
1212 | { | |
1213 | fprintf_unfiltered (gdb_stdlog, | |
1214 | "SC: lwp kill %d %s\n", | |
1215 | ret, | |
1216 | errno ? safe_strerror (errno) : "ERRNO-OK"); | |
1217 | } | |
1218 | ||
1219 | lp->signalled = 1; | |
1220 | gdb_assert (lp->status == 0); | |
1221 | } | |
1222 | ||
1223 | return 0; | |
1224 | } | |
1225 | ||
1226 | /* Wait until LP is stopped. If DATA is non-null it is interpreted as | |
1227 | a pointer to a set of signals to be flushed immediately. */ | |
1228 | ||
1229 | static int | |
1230 | stop_wait_callback (struct lwp_info *lp, void *data) | |
1231 | { | |
1232 | sigset_t *flush_mask = data; | |
1233 | ||
1234 | if (!lp->stopped) | |
1235 | { | |
1236 | int status; | |
1237 | ||
1238 | status = wait_lwp (lp); | |
1239 | if (status == 0) | |
1240 | return 0; | |
1241 | ||
1242 | /* Ignore any signals in FLUSH_MASK. */ | |
1243 | if (flush_mask && sigismember (flush_mask, WSTOPSIG (status))) | |
1244 | { | |
1245 | if (!lp->signalled) | |
1246 | { | |
1247 | lp->stopped = 1; | |
1248 | return 0; | |
1249 | } | |
1250 | ||
1251 | errno = 0; | |
1252 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
1253 | if (debug_linux_nat) | |
1254 | fprintf_unfiltered (gdb_stdlog, | |
1255 | "PTRACE_CONT %s, 0, 0 (%s)\n", | |
1256 | target_pid_to_str (lp->ptid), | |
1257 | errno ? safe_strerror (errno) : "OK"); | |
1258 | ||
1259 | return stop_wait_callback (lp, flush_mask); | |
1260 | } | |
1261 | ||
1262 | if (WSTOPSIG (status) != SIGSTOP) | |
1263 | { | |
1264 | if (WSTOPSIG (status) == SIGTRAP) | |
1265 | { | |
1266 | /* If a LWP other than the LWP that we're reporting an | |
1267 | event for has hit a GDB breakpoint (as opposed to | |
1268 | some random trap signal), then just arrange for it to | |
1269 | hit it again later. We don't keep the SIGTRAP status | |
1270 | and don't forward the SIGTRAP signal to the LWP. We | |
1271 | will handle the current event, eventually we will | |
1272 | resume all LWPs, and this one will get its breakpoint | |
1273 | trap again. | |
1274 | ||
1275 | If we do not do this, then we run the risk that the | |
1276 | user will delete or disable the breakpoint, but the | |
1277 | thread will have already tripped on it. */ | |
1278 | ||
1279 | /* Now resume this LWP and get the SIGSTOP event. */ | |
1280 | errno = 0; | |
1281 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
1282 | if (debug_linux_nat) | |
1283 | { | |
1284 | fprintf_unfiltered (gdb_stdlog, | |
1285 | "PTRACE_CONT %s, 0, 0 (%s)\n", | |
1286 | target_pid_to_str (lp->ptid), | |
1287 | errno ? safe_strerror (errno) : "OK"); | |
1288 | ||
1289 | fprintf_unfiltered (gdb_stdlog, | |
1290 | "SWC: Candidate SIGTRAP event in %s\n", | |
1291 | target_pid_to_str (lp->ptid)); | |
1292 | } | |
1293 | /* Hold the SIGTRAP for handling by linux_nat_wait. */ | |
1294 | stop_wait_callback (lp, data); | |
1295 | /* If there's another event, throw it back into the queue. */ | |
1296 | if (lp->status) | |
1297 | { | |
1298 | if (debug_linux_nat) | |
1299 | { | |
1300 | fprintf_unfiltered (gdb_stdlog, | |
1301 | "SWC: kill %s, %s\n", | |
1302 | target_pid_to_str (lp->ptid), | |
1303 | status_to_str ((int) status)); | |
1304 | } | |
1305 | kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (lp->status)); | |
1306 | } | |
1307 | /* Save the sigtrap event. */ | |
1308 | lp->status = status; | |
1309 | return 0; | |
1310 | } | |
1311 | else | |
1312 | { | |
1313 | /* The thread was stopped with a signal other than | |
1314 | SIGSTOP, and didn't accidentally trip a breakpoint. */ | |
1315 | ||
1316 | if (debug_linux_nat) | |
1317 | { | |
1318 | fprintf_unfiltered (gdb_stdlog, | |
1319 | "SWC: Pending event %s in %s\n", | |
1320 | status_to_str ((int) status), | |
1321 | target_pid_to_str (lp->ptid)); | |
1322 | } | |
1323 | /* Now resume this LWP and get the SIGSTOP event. */ | |
1324 | errno = 0; | |
1325 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
1326 | if (debug_linux_nat) | |
1327 | fprintf_unfiltered (gdb_stdlog, | |
1328 | "SWC: PTRACE_CONT %s, 0, 0 (%s)\n", | |
1329 | target_pid_to_str (lp->ptid), | |
1330 | errno ? safe_strerror (errno) : "OK"); | |
1331 | ||
1332 | /* Hold this event/waitstatus while we check to see if | |
1333 | there are any more (we still want to get that SIGSTOP). */ | |
1334 | stop_wait_callback (lp, data); | |
1335 | /* If the lp->status field is still empty, use it to hold | |
1336 | this event. If not, then this event must be returned | |
1337 | to the event queue of the LWP. */ | |
1338 | if (lp->status == 0) | |
1339 | lp->status = status; | |
1340 | else | |
1341 | { | |
1342 | if (debug_linux_nat) | |
1343 | { | |
1344 | fprintf_unfiltered (gdb_stdlog, | |
1345 | "SWC: kill %s, %s\n", | |
1346 | target_pid_to_str (lp->ptid), | |
1347 | status_to_str ((int) status)); | |
1348 | } | |
1349 | kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (status)); | |
1350 | } | |
1351 | return 0; | |
1352 | } | |
1353 | } | |
1354 | else | |
1355 | { | |
1356 | /* We caught the SIGSTOP that we intended to catch, so | |
1357 | there's no SIGSTOP pending. */ | |
1358 | lp->stopped = 1; | |
1359 | lp->signalled = 0; | |
1360 | } | |
1361 | } | |
1362 | ||
1363 | return 0; | |
1364 | } | |
1365 | ||
1366 | /* Check whether PID has any pending signals in FLUSH_MASK. If so set | |
1367 | the appropriate bits in PENDING, and return 1 - otherwise return 0. */ | |
1368 | ||
1369 | static int | |
1370 | linux_nat_has_pending (int pid, sigset_t *pending, sigset_t *flush_mask) | |
1371 | { | |
1372 | sigset_t blocked, ignored; | |
1373 | int i; | |
1374 | ||
1375 | linux_proc_pending_signals (pid, pending, &blocked, &ignored); | |
1376 | ||
1377 | if (!flush_mask) | |
1378 | return 0; | |
1379 | ||
1380 | for (i = 1; i < NSIG; i++) | |
1381 | if (sigismember (pending, i)) | |
1382 | if (!sigismember (flush_mask, i) | |
1383 | || sigismember (&blocked, i) | |
1384 | || sigismember (&ignored, i)) | |
1385 | sigdelset (pending, i); | |
1386 | ||
1387 | if (sigisemptyset (pending)) | |
1388 | return 0; | |
1389 | ||
1390 | return 1; | |
1391 | } | |
1392 | ||
1393 | /* DATA is interpreted as a mask of signals to flush. If LP has | |
1394 | signals pending, and they are all in the flush mask, then arrange | |
1395 | to flush them. LP should be stopped, as should all other threads | |
1396 | it might share a signal queue with. */ | |
1397 | ||
1398 | static int | |
1399 | flush_callback (struct lwp_info *lp, void *data) | |
1400 | { | |
1401 | sigset_t *flush_mask = data; | |
1402 | sigset_t pending, intersection, blocked, ignored; | |
1403 | int pid, status; | |
1404 | ||
1405 | /* Normally, when an LWP exits, it is removed from the LWP list. The | |
1406 | last LWP isn't removed till later, however. So if there is only | |
1407 | one LWP on the list, make sure it's alive. */ | |
1408 | if (lwp_list == lp && lp->next == NULL) | |
1409 | if (!linux_nat_thread_alive (lp->ptid)) | |
1410 | return 0; | |
1411 | ||
1412 | /* Just because the LWP is stopped doesn't mean that new signals | |
1413 | can't arrive from outside, so this function must be careful of | |
1414 | race conditions. However, because all threads are stopped, we | |
1415 | can assume that the pending mask will not shrink unless we resume | |
1416 | the LWP, and that it will then get another signal. We can't | |
1417 | control which one, however. */ | |
1418 | ||
1419 | if (lp->status) | |
1420 | { | |
1421 | if (debug_linux_nat) | |
1422 | printf_unfiltered ("FC: LP has pending status %06x\n", lp->status); | |
1423 | if (WIFSTOPPED (lp->status) && sigismember (flush_mask, WSTOPSIG (lp->status))) | |
1424 | lp->status = 0; | |
1425 | } | |
1426 | ||
1427 | while (linux_nat_has_pending (GET_LWP (lp->ptid), &pending, flush_mask)) | |
1428 | { | |
1429 | int ret; | |
1430 | ||
1431 | errno = 0; | |
1432 | ret = ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
1433 | if (debug_linux_nat) | |
1434 | fprintf_unfiltered (gdb_stderr, | |
1435 | "FC: Sent PTRACE_CONT, ret %d %d\n", ret, errno); | |
1436 | ||
1437 | lp->stopped = 0; | |
1438 | stop_wait_callback (lp, flush_mask); | |
1439 | if (debug_linux_nat) | |
1440 | fprintf_unfiltered (gdb_stderr, | |
1441 | "FC: Wait finished; saved status is %d\n", | |
1442 | lp->status); | |
1443 | } | |
1444 | ||
1445 | return 0; | |
1446 | } | |
1447 | ||
1448 | /* Return non-zero if LP has a wait status pending. */ | |
1449 | ||
1450 | static int | |
1451 | status_callback (struct lwp_info *lp, void *data) | |
1452 | { | |
1453 | /* Only report a pending wait status if we pretend that this has | |
1454 | indeed been resumed. */ | |
1455 | return (lp->status != 0 && lp->resumed); | |
1456 | } | |
1457 | ||
1458 | /* Return non-zero if LP isn't stopped. */ | |
1459 | ||
1460 | static int | |
1461 | running_callback (struct lwp_info *lp, void *data) | |
1462 | { | |
1463 | return (lp->stopped == 0 || (lp->status != 0 && lp->resumed)); | |
1464 | } | |
1465 | ||
1466 | /* Count the LWP's that have had events. */ | |
1467 | ||
1468 | static int | |
1469 | count_events_callback (struct lwp_info *lp, void *data) | |
1470 | { | |
1471 | int *count = data; | |
1472 | ||
1473 | gdb_assert (count != NULL); | |
1474 | ||
1475 | /* Count only LWPs that have a SIGTRAP event pending. */ | |
1476 | if (lp->status != 0 | |
1477 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) | |
1478 | (*count)++; | |
1479 | ||
1480 | return 0; | |
1481 | } | |
1482 | ||
1483 | /* Select the LWP (if any) that is currently being single-stepped. */ | |
1484 | ||
1485 | static int | |
1486 | select_singlestep_lwp_callback (struct lwp_info *lp, void *data) | |
1487 | { | |
1488 | if (lp->step && lp->status != 0) | |
1489 | return 1; | |
1490 | else | |
1491 | return 0; | |
1492 | } | |
1493 | ||
1494 | /* Select the Nth LWP that has had a SIGTRAP event. */ | |
1495 | ||
1496 | static int | |
1497 | select_event_lwp_callback (struct lwp_info *lp, void *data) | |
1498 | { | |
1499 | int *selector = data; | |
1500 | ||
1501 | gdb_assert (selector != NULL); | |
1502 | ||
1503 | /* Select only LWPs that have a SIGTRAP event pending. */ | |
1504 | if (lp->status != 0 | |
1505 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) | |
1506 | if ((*selector)-- == 0) | |
1507 | return 1; | |
1508 | ||
1509 | return 0; | |
1510 | } | |
1511 | ||
1512 | static int | |
1513 | cancel_breakpoints_callback (struct lwp_info *lp, void *data) | |
1514 | { | |
1515 | struct lwp_info *event_lp = data; | |
1516 | ||
1517 | /* Leave the LWP that has been elected to receive a SIGTRAP alone. */ | |
1518 | if (lp == event_lp) | |
1519 | return 0; | |
1520 | ||
1521 | /* If a LWP other than the LWP that we're reporting an event for has | |
1522 | hit a GDB breakpoint (as opposed to some random trap signal), | |
1523 | then just arrange for it to hit it again later. We don't keep | |
1524 | the SIGTRAP status and don't forward the SIGTRAP signal to the | |
1525 | LWP. We will handle the current event, eventually we will resume | |
1526 | all LWPs, and this one will get its breakpoint trap again. | |
1527 | ||
1528 | If we do not do this, then we run the risk that the user will | |
1529 | delete or disable the breakpoint, but the LWP will have already | |
1530 | tripped on it. */ | |
1531 | ||
1532 | if (lp->status != 0 | |
1533 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP | |
1534 | && breakpoint_inserted_here_p (read_pc_pid (lp->ptid) - | |
1535 | DECR_PC_AFTER_BREAK)) | |
1536 | { | |
1537 | if (debug_linux_nat) | |
1538 | fprintf_unfiltered (gdb_stdlog, | |
1539 | "CBC: Push back breakpoint for %s\n", | |
1540 | target_pid_to_str (lp->ptid)); | |
1541 | ||
1542 | /* Back up the PC if necessary. */ | |
1543 | if (DECR_PC_AFTER_BREAK) | |
1544 | write_pc_pid (read_pc_pid (lp->ptid) - DECR_PC_AFTER_BREAK, lp->ptid); | |
1545 | ||
1546 | /* Throw away the SIGTRAP. */ | |
1547 | lp->status = 0; | |
1548 | } | |
1549 | ||
1550 | return 0; | |
1551 | } | |
1552 | ||
1553 | /* Select one LWP out of those that have events pending. */ | |
1554 | ||
1555 | static void | |
1556 | select_event_lwp (struct lwp_info **orig_lp, int *status) | |
1557 | { | |
1558 | int num_events = 0; | |
1559 | int random_selector; | |
1560 | struct lwp_info *event_lp; | |
1561 | ||
1562 | /* Record the wait status for the origional LWP. */ | |
1563 | (*orig_lp)->status = *status; | |
1564 | ||
1565 | /* Give preference to any LWP that is being single-stepped. */ | |
1566 | event_lp = iterate_over_lwps (select_singlestep_lwp_callback, NULL); | |
1567 | if (event_lp != NULL) | |
1568 | { | |
1569 | if (debug_linux_nat) | |
1570 | fprintf_unfiltered (gdb_stdlog, | |
1571 | "SEL: Select single-step %s\n", | |
1572 | target_pid_to_str (event_lp->ptid)); | |
1573 | } | |
1574 | else | |
1575 | { | |
1576 | /* No single-stepping LWP. Select one at random, out of those | |
1577 | which have had SIGTRAP events. */ | |
1578 | ||
1579 | /* First see how many SIGTRAP events we have. */ | |
1580 | iterate_over_lwps (count_events_callback, &num_events); | |
1581 | ||
1582 | /* Now randomly pick a LWP out of those that have had a SIGTRAP. */ | |
1583 | random_selector = (int) | |
1584 | ((num_events * (double) rand ()) / (RAND_MAX + 1.0)); | |
1585 | ||
1586 | if (debug_linux_nat && num_events > 1) | |
1587 | fprintf_unfiltered (gdb_stdlog, | |
1588 | "SEL: Found %d SIGTRAP events, selecting #%d\n", | |
1589 | num_events, random_selector); | |
1590 | ||
1591 | event_lp = iterate_over_lwps (select_event_lwp_callback, | |
1592 | &random_selector); | |
1593 | } | |
1594 | ||
1595 | if (event_lp != NULL) | |
1596 | { | |
1597 | /* Switch the event LWP. */ | |
1598 | *orig_lp = event_lp; | |
1599 | *status = event_lp->status; | |
1600 | } | |
1601 | ||
1602 | /* Flush the wait status for the event LWP. */ | |
1603 | (*orig_lp)->status = 0; | |
1604 | } | |
1605 | ||
1606 | /* Return non-zero if LP has been resumed. */ | |
1607 | ||
1608 | static int | |
1609 | resumed_callback (struct lwp_info *lp, void *data) | |
1610 | { | |
1611 | return lp->resumed; | |
1612 | } | |
1613 | ||
1614 | #ifdef CHILD_WAIT | |
1615 | ||
1616 | /* We need to override child_wait to support attaching to cloned | |
1617 | processes, since a normal wait (as done by the default version) | |
1618 | ignores those processes. */ | |
1619 | ||
1620 | /* Wait for child PTID to do something. Return id of the child, | |
1621 | minus_one_ptid in case of error; store status into *OURSTATUS. */ | |
1622 | ||
1623 | ptid_t | |
1624 | child_wait (ptid_t ptid, struct target_waitstatus *ourstatus) | |
1625 | { | |
1626 | int save_errno; | |
1627 | int status; | |
1628 | pid_t pid; | |
1629 | ||
1630 | ourstatus->kind = TARGET_WAITKIND_IGNORE; | |
1631 | ||
1632 | do | |
1633 | { | |
1634 | set_sigint_trap (); /* Causes SIGINT to be passed on to the | |
1635 | attached process. */ | |
1636 | set_sigio_trap (); | |
1637 | ||
1638 | pid = waitpid (GET_PID (ptid), &status, 0); | |
1639 | if (pid == -1 && errno == ECHILD) | |
1640 | /* Try again with __WCLONE to check cloned processes. */ | |
1641 | pid = waitpid (GET_PID (ptid), &status, __WCLONE); | |
1642 | ||
1643 | if (debug_linux_nat) | |
1644 | { | |
1645 | fprintf_unfiltered (gdb_stdlog, | |
1646 | "CW: waitpid %ld received %s\n", | |
1647 | (long) pid, status_to_str (status)); | |
1648 | } | |
1649 | ||
1650 | save_errno = errno; | |
1651 | ||
1652 | /* Make sure we don't report an event for the exit of the | |
1653 | original program, if we've detached from it. */ | |
1654 | if (pid != -1 && !WIFSTOPPED (status) && pid != GET_PID (inferior_ptid)) | |
1655 | { | |
1656 | pid = -1; | |
1657 | save_errno = EINTR; | |
1658 | } | |
1659 | ||
1660 | /* Check for stop events reported by a process we didn't already | |
1661 | know about - in this case, anything other than inferior_ptid. | |
1662 | ||
1663 | If we're expecting to receive stopped processes after fork, | |
1664 | vfork, and clone events, then we'll just add the new one to | |
1665 | our list and go back to waiting for the event to be reported | |
1666 | - the stopped process might be returned from waitpid before | |
1667 | or after the event is. If we want to handle debugging of | |
1668 | CLONE_PTRACE processes we need to do more here, i.e. switch | |
1669 | to multi-threaded mode. */ | |
1670 | if (pid != -1 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP | |
1671 | && pid != GET_PID (inferior_ptid)) | |
1672 | { | |
1673 | linux_record_stopped_pid (pid); | |
1674 | pid = -1; | |
1675 | save_errno = EINTR; | |
1676 | } | |
1677 | ||
1678 | /* Handle GNU/Linux's extended waitstatus for trace events. */ | |
1679 | if (pid != -1 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP | |
1680 | && status >> 16 != 0) | |
1681 | { | |
1682 | linux_handle_extended_wait (pid, status, ourstatus); | |
1683 | ||
1684 | /* If we see a clone event, detach the child, and don't | |
1685 | report the event. It would be nice to offer some way to | |
1686 | switch into a non-thread-db based threaded mode at this | |
1687 | point. */ | |
1688 | if (ourstatus->kind == TARGET_WAITKIND_SPURIOUS) | |
1689 | { | |
1690 | ptrace (PTRACE_DETACH, ourstatus->value.related_pid, 0, 0); | |
1691 | ourstatus->kind = TARGET_WAITKIND_IGNORE; | |
1692 | ptrace (PTRACE_CONT, pid, 0, 0); | |
1693 | pid = -1; | |
1694 | save_errno = EINTR; | |
1695 | } | |
1696 | } | |
1697 | ||
1698 | clear_sigio_trap (); | |
1699 | clear_sigint_trap (); | |
1700 | } | |
1701 | while (pid == -1 && save_errno == EINTR); | |
1702 | ||
1703 | if (pid == -1) | |
1704 | { | |
1705 | warning ("Child process unexpectedly missing: %s", | |
1706 | safe_strerror (errno)); | |
1707 | ||
1708 | /* Claim it exited with unknown signal. */ | |
1709 | ourstatus->kind = TARGET_WAITKIND_SIGNALLED; | |
1710 | ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN; | |
1711 | return minus_one_ptid; | |
1712 | } | |
1713 | ||
1714 | if (ourstatus->kind == TARGET_WAITKIND_IGNORE) | |
1715 | store_waitstatus (ourstatus, status); | |
1716 | ||
1717 | return pid_to_ptid (pid); | |
1718 | } | |
1719 | ||
1720 | #endif | |
1721 | ||
1722 | /* Stop an active thread, verify it still exists, then resume it. */ | |
1723 | ||
1724 | static int | |
1725 | stop_and_resume_callback (struct lwp_info *lp, void *data) | |
1726 | { | |
1727 | struct lwp_info *ptr; | |
1728 | ||
1729 | if (!lp->stopped && !lp->signalled) | |
1730 | { | |
1731 | stop_callback (lp, NULL); | |
1732 | stop_wait_callback (lp, NULL); | |
1733 | /* Resume if the lwp still exists. */ | |
1734 | for (ptr = lwp_list; ptr; ptr = ptr->next) | |
1735 | if (lp == ptr) | |
1736 | { | |
1737 | resume_callback (lp, NULL); | |
1738 | resume_set_callback (lp, NULL); | |
1739 | } | |
1740 | } | |
1741 | return 0; | |
1742 | } | |
1743 | ||
1744 | static ptid_t | |
1745 | linux_nat_wait (ptid_t ptid, struct target_waitstatus *ourstatus) | |
1746 | { | |
1747 | struct lwp_info *lp = NULL; | |
1748 | int options = 0; | |
1749 | int status = 0; | |
1750 | pid_t pid = PIDGET (ptid); | |
1751 | sigset_t flush_mask; | |
1752 | ||
1753 | sigemptyset (&flush_mask); | |
1754 | ||
1755 | /* Make sure SIGCHLD is blocked. */ | |
1756 | if (!sigismember (&blocked_mask, SIGCHLD)) | |
1757 | { | |
1758 | sigaddset (&blocked_mask, SIGCHLD); | |
1759 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
1760 | } | |
1761 | ||
1762 | retry: | |
1763 | ||
1764 | /* Make sure there is at least one LWP that has been resumed, at | |
1765 | least if there are any LWPs at all. */ | |
1766 | gdb_assert (num_lwps == 0 || iterate_over_lwps (resumed_callback, NULL)); | |
1767 | ||
1768 | /* First check if there is a LWP with a wait status pending. */ | |
1769 | if (pid == -1) | |
1770 | { | |
1771 | /* Any LWP that's been resumed will do. */ | |
1772 | lp = iterate_over_lwps (status_callback, NULL); | |
1773 | if (lp) | |
1774 | { | |
1775 | status = lp->status; | |
1776 | lp->status = 0; | |
1777 | ||
1778 | if (debug_linux_nat && status) | |
1779 | fprintf_unfiltered (gdb_stdlog, | |
1780 | "LLW: Using pending wait status %s for %s.\n", | |
1781 | status_to_str (status), | |
1782 | target_pid_to_str (lp->ptid)); | |
1783 | } | |
1784 | ||
1785 | /* But if we don't fine one, we'll have to wait, and check both | |
1786 | cloned and uncloned processes. We start with the cloned | |
1787 | processes. */ | |
1788 | options = __WCLONE | WNOHANG; | |
1789 | } | |
1790 | else if (is_lwp (ptid)) | |
1791 | { | |
1792 | if (debug_linux_nat) | |
1793 | fprintf_unfiltered (gdb_stdlog, | |
1794 | "LLW: Waiting for specific LWP %s.\n", | |
1795 | target_pid_to_str (ptid)); | |
1796 | ||
1797 | /* We have a specific LWP to check. */ | |
1798 | lp = find_lwp_pid (ptid); | |
1799 | gdb_assert (lp); | |
1800 | status = lp->status; | |
1801 | lp->status = 0; | |
1802 | ||
1803 | if (debug_linux_nat && status) | |
1804 | fprintf_unfiltered (gdb_stdlog, | |
1805 | "LLW: Using pending wait status %s for %s.\n", | |
1806 | status_to_str (status), | |
1807 | target_pid_to_str (lp->ptid)); | |
1808 | ||
1809 | /* If we have to wait, take into account whether PID is a cloned | |
1810 | process or not. And we have to convert it to something that | |
1811 | the layer beneath us can understand. */ | |
1812 | options = lp->cloned ? __WCLONE : 0; | |
1813 | pid = GET_LWP (ptid); | |
1814 | } | |
1815 | ||
1816 | if (status && lp->signalled) | |
1817 | { | |
1818 | /* A pending SIGSTOP may interfere with the normal stream of | |
1819 | events. In a typical case where interference is a problem, | |
1820 | we have a SIGSTOP signal pending for LWP A while | |
1821 | single-stepping it, encounter an event in LWP B, and take the | |
1822 | pending SIGSTOP while trying to stop LWP A. After processing | |
1823 | the event in LWP B, LWP A is continued, and we'll never see | |
1824 | the SIGTRAP associated with the last time we were | |
1825 | single-stepping LWP A. */ | |
1826 | ||
1827 | /* Resume the thread. It should halt immediately returning the | |
1828 | pending SIGSTOP. */ | |
1829 | registers_changed (); | |
1830 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, | |
1831 | TARGET_SIGNAL_0); | |
1832 | if (debug_linux_nat) | |
1833 | fprintf_unfiltered (gdb_stdlog, | |
1834 | "LLW: %s %s, 0, 0 (expect SIGSTOP)\n", | |
1835 | lp->step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT", | |
1836 | target_pid_to_str (lp->ptid)); | |
1837 | lp->stopped = 0; | |
1838 | gdb_assert (lp->resumed); | |
1839 | ||
1840 | /* This should catch the pending SIGSTOP. */ | |
1841 | stop_wait_callback (lp, NULL); | |
1842 | } | |
1843 | ||
1844 | set_sigint_trap (); /* Causes SIGINT to be passed on to the | |
1845 | attached process. */ | |
1846 | set_sigio_trap (); | |
1847 | ||
1848 | while (status == 0) | |
1849 | { | |
1850 | pid_t lwpid; | |
1851 | ||
1852 | lwpid = waitpid (pid, &status, options); | |
1853 | if (lwpid > 0) | |
1854 | { | |
1855 | gdb_assert (pid == -1 || lwpid == pid); | |
1856 | ||
1857 | if (debug_linux_nat) | |
1858 | { | |
1859 | fprintf_unfiltered (gdb_stdlog, | |
1860 | "LLW: waitpid %ld received %s\n", | |
1861 | (long) lwpid, status_to_str (status)); | |
1862 | } | |
1863 | ||
1864 | lp = find_lwp_pid (pid_to_ptid (lwpid)); | |
1865 | ||
1866 | /* Check for stop events reported by a process we didn't | |
1867 | already know about - anything not already in our LWP | |
1868 | list. | |
1869 | ||
1870 | If we're expecting to receive stopped processes after | |
1871 | fork, vfork, and clone events, then we'll just add the | |
1872 | new one to our list and go back to waiting for the event | |
1873 | to be reported - the stopped process might be returned | |
1874 | from waitpid before or after the event is. */ | |
1875 | if (WIFSTOPPED (status) && !lp) | |
1876 | { | |
1877 | linux_record_stopped_pid (lwpid); | |
1878 | status = 0; | |
1879 | continue; | |
1880 | } | |
1881 | ||
1882 | /* Make sure we don't report an event for the exit of an LWP not in | |
1883 | our list, i.e. not part of the current process. This can happen | |
1884 | if we detach from a program we original forked and then it | |
1885 | exits. */ | |
1886 | if (!WIFSTOPPED (status) && !lp) | |
1887 | { | |
1888 | status = 0; | |
1889 | continue; | |
1890 | } | |
1891 | ||
1892 | /* NOTE drow/2003-06-17: This code seems to be meant for debugging | |
1893 | CLONE_PTRACE processes which do not use the thread library - | |
1894 | otherwise we wouldn't find the new LWP this way. That doesn't | |
1895 | currently work, and the following code is currently unreachable | |
1896 | due to the two blocks above. If it's fixed some day, this code | |
1897 | should be broken out into a function so that we can also pick up | |
1898 | LWPs from the new interface. */ | |
1899 | if (!lp) | |
1900 | { | |
1901 | lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid))); | |
1902 | if (options & __WCLONE) | |
1903 | lp->cloned = 1; | |
1904 | ||
1905 | if (threaded) | |
1906 | { | |
1907 | gdb_assert (WIFSTOPPED (status) | |
1908 | && WSTOPSIG (status) == SIGSTOP); | |
1909 | lp->signalled = 1; | |
1910 | ||
1911 | if (!in_thread_list (inferior_ptid)) | |
1912 | { | |
1913 | inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid), | |
1914 | GET_PID (inferior_ptid)); | |
1915 | add_thread (inferior_ptid); | |
1916 | } | |
1917 | ||
1918 | add_thread (lp->ptid); | |
1919 | printf_unfiltered ("[New %s]\n", | |
1920 | target_pid_to_str (lp->ptid)); | |
1921 | } | |
1922 | } | |
1923 | ||
1924 | /* Handle GNU/Linux's extended waitstatus for trace events. */ | |
1925 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0) | |
1926 | { | |
1927 | if (debug_linux_nat) | |
1928 | fprintf_unfiltered (gdb_stdlog, | |
1929 | "LLW: Handling extended status 0x%06x\n", | |
1930 | status); | |
1931 | if (linux_nat_handle_extended (lp, status)) | |
1932 | { | |
1933 | status = 0; | |
1934 | continue; | |
1935 | } | |
1936 | } | |
1937 | ||
1938 | /* Check if the thread has exited. */ | |
1939 | if ((WIFEXITED (status) || WIFSIGNALED (status)) && num_lwps > 1) | |
1940 | { | |
1941 | if (in_thread_list (lp->ptid)) | |
1942 | { | |
1943 | /* Core GDB cannot deal with us deleting the current | |
1944 | thread. */ | |
1945 | if (!ptid_equal (lp->ptid, inferior_ptid)) | |
1946 | delete_thread (lp->ptid); | |
1947 | printf_unfiltered ("[%s exited]\n", | |
1948 | target_pid_to_str (lp->ptid)); | |
1949 | } | |
1950 | ||
1951 | /* If this is the main thread, we must stop all threads and | |
1952 | verify if they are still alive. This is because in the nptl | |
1953 | thread model, there is no signal issued for exiting LWPs | |
1954 | other than the main thread. We only get the main thread | |
1955 | exit signal once all child threads have already exited. | |
1956 | If we stop all the threads and use the stop_wait_callback | |
1957 | to check if they have exited we can determine whether this | |
1958 | signal should be ignored or whether it means the end of the | |
1959 | debugged application, regardless of which threading model | |
1960 | is being used. */ | |
1961 | if (GET_PID (lp->ptid) == GET_LWP (lp->ptid)) | |
1962 | { | |
1963 | lp->stopped = 1; | |
1964 | iterate_over_lwps (stop_and_resume_callback, NULL); | |
1965 | } | |
1966 | ||
1967 | if (debug_linux_nat) | |
1968 | fprintf_unfiltered (gdb_stdlog, | |
1969 | "LLW: %s exited.\n", | |
1970 | target_pid_to_str (lp->ptid)); | |
1971 | ||
1972 | delete_lwp (lp->ptid); | |
1973 | ||
1974 | /* If there is at least one more LWP, then the exit signal | |
1975 | was not the end of the debugged application and should be | |
1976 | ignored. */ | |
1977 | if (num_lwps > 0) | |
1978 | { | |
1979 | /* Make sure there is at least one thread running. */ | |
1980 | gdb_assert (iterate_over_lwps (running_callback, NULL)); | |
1981 | ||
1982 | /* Discard the event. */ | |
1983 | status = 0; | |
1984 | continue; | |
1985 | } | |
1986 | } | |
1987 | ||
1988 | /* Check if the current LWP has previously exited. In the nptl | |
1989 | thread model, LWPs other than the main thread do not issue | |
1990 | signals when they exit so we must check whenever the thread | |
1991 | has stopped. A similar check is made in stop_wait_callback(). */ | |
1992 | if (num_lwps > 1 && !linux_nat_thread_alive (lp->ptid)) | |
1993 | { | |
1994 | if (in_thread_list (lp->ptid)) | |
1995 | { | |
1996 | /* Core GDB cannot deal with us deleting the current | |
1997 | thread. */ | |
1998 | if (!ptid_equal (lp->ptid, inferior_ptid)) | |
1999 | delete_thread (lp->ptid); | |
2000 | printf_unfiltered ("[%s exited]\n", | |
2001 | target_pid_to_str (lp->ptid)); | |
2002 | } | |
2003 | if (debug_linux_nat) | |
2004 | fprintf_unfiltered (gdb_stdlog, | |
2005 | "LLW: %s exited.\n", | |
2006 | target_pid_to_str (lp->ptid)); | |
2007 | ||
2008 | delete_lwp (lp->ptid); | |
2009 | ||
2010 | /* Make sure there is at least one thread running. */ | |
2011 | gdb_assert (iterate_over_lwps (running_callback, NULL)); | |
2012 | ||
2013 | /* Discard the event. */ | |
2014 | status = 0; | |
2015 | continue; | |
2016 | } | |
2017 | ||
2018 | /* Make sure we don't report a SIGSTOP that we sent | |
2019 | ourselves in an attempt to stop an LWP. */ | |
2020 | if (lp->signalled | |
2021 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP) | |
2022 | { | |
2023 | if (debug_linux_nat) | |
2024 | fprintf_unfiltered (gdb_stdlog, | |
2025 | "LLW: Delayed SIGSTOP caught for %s.\n", | |
2026 | target_pid_to_str (lp->ptid)); | |
2027 | ||
2028 | /* This is a delayed SIGSTOP. */ | |
2029 | lp->signalled = 0; | |
2030 | ||
2031 | registers_changed (); | |
2032 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, | |
2033 | TARGET_SIGNAL_0); | |
2034 | if (debug_linux_nat) | |
2035 | fprintf_unfiltered (gdb_stdlog, | |
2036 | "LLW: %s %s, 0, 0 (discard SIGSTOP)\n", | |
2037 | lp->step ? | |
2038 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", | |
2039 | target_pid_to_str (lp->ptid)); | |
2040 | ||
2041 | lp->stopped = 0; | |
2042 | gdb_assert (lp->resumed); | |
2043 | ||
2044 | /* Discard the event. */ | |
2045 | status = 0; | |
2046 | continue; | |
2047 | } | |
2048 | ||
2049 | break; | |
2050 | } | |
2051 | ||
2052 | if (pid == -1) | |
2053 | { | |
2054 | /* Alternate between checking cloned and uncloned processes. */ | |
2055 | options ^= __WCLONE; | |
2056 | ||
2057 | /* And suspend every time we have checked both. */ | |
2058 | if (options & __WCLONE) | |
2059 | sigsuspend (&suspend_mask); | |
2060 | } | |
2061 | ||
2062 | /* We shouldn't end up here unless we want to try again. */ | |
2063 | gdb_assert (status == 0); | |
2064 | } | |
2065 | ||
2066 | clear_sigio_trap (); | |
2067 | clear_sigint_trap (); | |
2068 | ||
2069 | gdb_assert (lp); | |
2070 | ||
2071 | /* Don't report signals that GDB isn't interested in, such as | |
2072 | signals that are neither printed nor stopped upon. Stopping all | |
2073 | threads can be a bit time-consuming so if we want decent | |
2074 | performance with heavily multi-threaded programs, especially when | |
2075 | they're using a high frequency timer, we'd better avoid it if we | |
2076 | can. */ | |
2077 | ||
2078 | if (WIFSTOPPED (status)) | |
2079 | { | |
2080 | int signo = target_signal_from_host (WSTOPSIG (status)); | |
2081 | ||
2082 | if (signal_stop_state (signo) == 0 | |
2083 | && signal_print_state (signo) == 0 | |
2084 | && signal_pass_state (signo) == 1) | |
2085 | { | |
2086 | /* FIMXE: kettenis/2001-06-06: Should we resume all threads | |
2087 | here? It is not clear we should. GDB may not expect | |
2088 | other threads to run. On the other hand, not resuming | |
2089 | newly attached threads may cause an unwanted delay in | |
2090 | getting them running. */ | |
2091 | registers_changed (); | |
2092 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, signo); | |
2093 | if (debug_linux_nat) | |
2094 | fprintf_unfiltered (gdb_stdlog, | |
2095 | "LLW: %s %s, %s (preempt 'handle')\n", | |
2096 | lp->step ? | |
2097 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", | |
2098 | target_pid_to_str (lp->ptid), | |
2099 | signo ? strsignal (signo) : "0"); | |
2100 | lp->stopped = 0; | |
2101 | status = 0; | |
2102 | goto retry; | |
2103 | } | |
2104 | ||
2105 | if (signo == TARGET_SIGNAL_INT && signal_pass_state (signo) == 0) | |
2106 | { | |
2107 | /* If ^C/BREAK is typed at the tty/console, SIGINT gets | |
2108 | forwarded to the entire process group, that is, all LWP's | |
2109 | will receive it. Since we only want to report it once, | |
2110 | we try to flush it from all LWPs except this one. */ | |
2111 | sigaddset (&flush_mask, SIGINT); | |
2112 | } | |
2113 | } | |
2114 | ||
2115 | /* This LWP is stopped now. */ | |
2116 | lp->stopped = 1; | |
2117 | ||
2118 | if (debug_linux_nat) | |
2119 | fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n", | |
2120 | status_to_str (status), target_pid_to_str (lp->ptid)); | |
2121 | ||
2122 | /* Now stop all other LWP's ... */ | |
2123 | iterate_over_lwps (stop_callback, NULL); | |
2124 | ||
2125 | /* ... and wait until all of them have reported back that they're no | |
2126 | longer running. */ | |
2127 | iterate_over_lwps (stop_wait_callback, &flush_mask); | |
2128 | iterate_over_lwps (flush_callback, &flush_mask); | |
2129 | ||
2130 | /* If we're not waiting for a specific LWP, choose an event LWP from | |
2131 | among those that have had events. Giving equal priority to all | |
2132 | LWPs that have had events helps prevent starvation. */ | |
2133 | if (pid == -1) | |
2134 | select_event_lwp (&lp, &status); | |
2135 | ||
2136 | /* Now that we've selected our final event LWP, cancel any | |
2137 | breakpoints in other LWPs that have hit a GDB breakpoint. See | |
2138 | the comment in cancel_breakpoints_callback to find out why. */ | |
2139 | iterate_over_lwps (cancel_breakpoints_callback, lp); | |
2140 | ||
2141 | /* If we're not running in "threaded" mode, we'll report the bare | |
2142 | process id. */ | |
2143 | ||
2144 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP) | |
2145 | { | |
2146 | trap_ptid = (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid))); | |
2147 | if (debug_linux_nat) | |
2148 | fprintf_unfiltered (gdb_stdlog, | |
2149 | "LLW: trap_ptid is %s.\n", | |
2150 | target_pid_to_str (trap_ptid)); | |
2151 | } | |
2152 | else | |
2153 | trap_ptid = null_ptid; | |
2154 | ||
2155 | if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE) | |
2156 | { | |
2157 | *ourstatus = lp->waitstatus; | |
2158 | lp->waitstatus.kind = TARGET_WAITKIND_IGNORE; | |
2159 | } | |
2160 | else | |
2161 | store_waitstatus (ourstatus, status); | |
2162 | ||
2163 | return (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid))); | |
2164 | } | |
2165 | ||
2166 | static int | |
2167 | kill_callback (struct lwp_info *lp, void *data) | |
2168 | { | |
2169 | errno = 0; | |
2170 | ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0); | |
2171 | if (debug_linux_nat) | |
2172 | fprintf_unfiltered (gdb_stdlog, | |
2173 | "KC: PTRACE_KILL %s, 0, 0 (%s)\n", | |
2174 | target_pid_to_str (lp->ptid), | |
2175 | errno ? safe_strerror (errno) : "OK"); | |
2176 | ||
2177 | return 0; | |
2178 | } | |
2179 | ||
2180 | static int | |
2181 | kill_wait_callback (struct lwp_info *lp, void *data) | |
2182 | { | |
2183 | pid_t pid; | |
2184 | ||
2185 | /* We must make sure that there are no pending events (delayed | |
2186 | SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current | |
2187 | program doesn't interfere with any following debugging session. */ | |
2188 | ||
2189 | /* For cloned processes we must check both with __WCLONE and | |
2190 | without, since the exit status of a cloned process isn't reported | |
2191 | with __WCLONE. */ | |
2192 | if (lp->cloned) | |
2193 | { | |
2194 | do | |
2195 | { | |
2196 | pid = waitpid (GET_LWP (lp->ptid), NULL, __WCLONE); | |
2197 | if (pid != (pid_t) -1 && debug_linux_nat) | |
2198 | { | |
2199 | fprintf_unfiltered (gdb_stdlog, | |
2200 | "KWC: wait %s received unknown.\n", | |
2201 | target_pid_to_str (lp->ptid)); | |
2202 | } | |
2203 | } | |
2204 | while (pid == GET_LWP (lp->ptid)); | |
2205 | ||
2206 | gdb_assert (pid == -1 && errno == ECHILD); | |
2207 | } | |
2208 | ||
2209 | do | |
2210 | { | |
2211 | pid = waitpid (GET_LWP (lp->ptid), NULL, 0); | |
2212 | if (pid != (pid_t) -1 && debug_linux_nat) | |
2213 | { | |
2214 | fprintf_unfiltered (gdb_stdlog, | |
2215 | "KWC: wait %s received unk.\n", | |
2216 | target_pid_to_str (lp->ptid)); | |
2217 | } | |
2218 | } | |
2219 | while (pid == GET_LWP (lp->ptid)); | |
2220 | ||
2221 | gdb_assert (pid == -1 && errno == ECHILD); | |
2222 | return 0; | |
2223 | } | |
2224 | ||
2225 | static void | |
2226 | linux_nat_kill (void) | |
2227 | { | |
2228 | /* Kill all LWP's ... */ | |
2229 | iterate_over_lwps (kill_callback, NULL); | |
2230 | ||
2231 | /* ... and wait until we've flushed all events. */ | |
2232 | iterate_over_lwps (kill_wait_callback, NULL); | |
2233 | ||
2234 | target_mourn_inferior (); | |
2235 | } | |
2236 | ||
2237 | static void | |
2238 | linux_nat_create_inferior (char *exec_file, char *allargs, char **env, | |
2239 | int from_tty) | |
2240 | { | |
2241 | child_ops.to_create_inferior (exec_file, allargs, env, from_tty); | |
2242 | } | |
2243 | ||
2244 | static void | |
2245 | linux_nat_mourn_inferior (void) | |
2246 | { | |
2247 | trap_ptid = null_ptid; | |
2248 | ||
2249 | /* Destroy LWP info; it's no longer valid. */ | |
2250 | init_lwp_list (); | |
2251 | ||
2252 | /* Restore the original signal mask. */ | |
2253 | sigprocmask (SIG_SETMASK, &normal_mask, NULL); | |
2254 | sigemptyset (&blocked_mask); | |
2255 | ||
2256 | child_ops.to_mourn_inferior (); | |
2257 | } | |
2258 | ||
2259 | static int | |
2260 | linux_nat_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write, | |
2261 | struct mem_attrib *attrib, struct target_ops *target) | |
2262 | { | |
2263 | struct cleanup *old_chain = save_inferior_ptid (); | |
2264 | int xfer; | |
2265 | ||
2266 | if (is_lwp (inferior_ptid)) | |
2267 | inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid)); | |
2268 | ||
2269 | xfer = linux_proc_xfer_memory (memaddr, myaddr, len, write, attrib, target); | |
2270 | if (xfer == 0) | |
2271 | xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target); | |
2272 | ||
2273 | do_cleanups (old_chain); | |
2274 | return xfer; | |
2275 | } | |
2276 | ||
2277 | static int | |
2278 | linux_nat_thread_alive (ptid_t ptid) | |
2279 | { | |
2280 | gdb_assert (is_lwp (ptid)); | |
2281 | ||
2282 | errno = 0; | |
2283 | ptrace (PTRACE_PEEKUSER, GET_LWP (ptid), 0, 0); | |
2284 | if (debug_linux_nat) | |
2285 | fprintf_unfiltered (gdb_stdlog, | |
2286 | "LLTA: PTRACE_PEEKUSER %s, 0, 0 (%s)\n", | |
2287 | target_pid_to_str (ptid), | |
2288 | errno ? safe_strerror (errno) : "OK"); | |
2289 | if (errno) | |
2290 | return 0; | |
2291 | ||
2292 | return 1; | |
2293 | } | |
2294 | ||
2295 | static char * | |
2296 | linux_nat_pid_to_str (ptid_t ptid) | |
2297 | { | |
2298 | static char buf[64]; | |
2299 | ||
2300 | if (is_lwp (ptid)) | |
2301 | { | |
2302 | snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid)); | |
2303 | return buf; | |
2304 | } | |
2305 | ||
2306 | return normal_pid_to_str (ptid); | |
2307 | } | |
2308 | ||
2309 | static void | |
2310 | init_linux_nat_ops (void) | |
2311 | { | |
2312 | #if 0 | |
2313 | linux_nat_ops.to_open = linux_nat_open; | |
2314 | #endif | |
2315 | linux_nat_ops.to_shortname = "lwp-layer"; | |
2316 | linux_nat_ops.to_longname = "lwp-layer"; | |
2317 | linux_nat_ops.to_doc = "Low level threads support (LWP layer)"; | |
2318 | linux_nat_ops.to_attach = linux_nat_attach; | |
2319 | linux_nat_ops.to_detach = linux_nat_detach; | |
2320 | linux_nat_ops.to_resume = linux_nat_resume; | |
2321 | linux_nat_ops.to_wait = linux_nat_wait; | |
2322 | /* fetch_inferior_registers and store_inferior_registers will | |
2323 | honor the LWP id, so we can use them directly. */ | |
2324 | linux_nat_ops.to_fetch_registers = fetch_inferior_registers; | |
2325 | linux_nat_ops.to_store_registers = store_inferior_registers; | |
2326 | linux_nat_ops.to_xfer_memory = linux_nat_xfer_memory; | |
2327 | linux_nat_ops.to_kill = linux_nat_kill; | |
2328 | linux_nat_ops.to_create_inferior = linux_nat_create_inferior; | |
2329 | linux_nat_ops.to_mourn_inferior = linux_nat_mourn_inferior; | |
2330 | linux_nat_ops.to_thread_alive = linux_nat_thread_alive; | |
2331 | linux_nat_ops.to_pid_to_str = linux_nat_pid_to_str; | |
2332 | linux_nat_ops.to_post_startup_inferior = child_post_startup_inferior; | |
2333 | linux_nat_ops.to_post_attach = child_post_attach; | |
2334 | linux_nat_ops.to_insert_fork_catchpoint = child_insert_fork_catchpoint; | |
2335 | linux_nat_ops.to_insert_vfork_catchpoint = child_insert_vfork_catchpoint; | |
2336 | linux_nat_ops.to_insert_exec_catchpoint = child_insert_exec_catchpoint; | |
2337 | ||
2338 | linux_nat_ops.to_stratum = thread_stratum; | |
2339 | linux_nat_ops.to_has_thread_control = tc_schedlock; | |
2340 | linux_nat_ops.to_magic = OPS_MAGIC; | |
2341 | } | |
2342 | ||
2343 | static void | |
2344 | sigchld_handler (int signo) | |
2345 | { | |
2346 | /* Do nothing. The only reason for this handler is that it allows | |
2347 | us to use sigsuspend in linux_nat_wait above to wait for the | |
2348 | arrival of a SIGCHLD. */ | |
2349 | } | |
2350 | ||
2351 | void | |
2352 | _initialize_linux_nat (void) | |
2353 | { | |
2354 | struct sigaction action; | |
2355 | ||
2356 | extern void thread_db_init (struct target_ops *); | |
2357 | ||
2358 | init_linux_nat_ops (); | |
2359 | add_target (&linux_nat_ops); | |
2360 | thread_db_init (&linux_nat_ops); | |
2361 | ||
2362 | /* Save the original signal mask. */ | |
2363 | sigprocmask (SIG_SETMASK, NULL, &normal_mask); | |
2364 | ||
2365 | action.sa_handler = sigchld_handler; | |
2366 | sigemptyset (&action.sa_mask); | |
2367 | action.sa_flags = 0; | |
2368 | sigaction (SIGCHLD, &action, NULL); | |
2369 | ||
2370 | /* Make sure we don't block SIGCHLD during a sigsuspend. */ | |
2371 | sigprocmask (SIG_SETMASK, NULL, &suspend_mask); | |
2372 | sigdelset (&suspend_mask, SIGCHLD); | |
2373 | ||
2374 | sigemptyset (&blocked_mask); | |
2375 | ||
2376 | deprecated_add_show_from_set | |
2377 | (add_set_cmd ("lin-lwp", no_class, var_zinteger, | |
2378 | (char *) &debug_linux_nat, | |
2379 | "Set debugging of GNU/Linux lwp module.\n\ | |
2380 | Enables printf debugging output.\n", &setdebuglist), &showdebuglist); | |
2381 | } | |
2382 | \f | |
2383 | ||
2384 | /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to | |
2385 | the GNU/Linux Threads library and therefore doesn't really belong | |
2386 | here. */ | |
2387 | ||
2388 | /* Read variable NAME in the target and return its value if found. | |
2389 | Otherwise return zero. It is assumed that the type of the variable | |
2390 | is `int'. */ | |
2391 | ||
2392 | static int | |
2393 | get_signo (const char *name) | |
2394 | { | |
2395 | struct minimal_symbol *ms; | |
2396 | int signo; | |
2397 | ||
2398 | ms = lookup_minimal_symbol (name, NULL, NULL); | |
2399 | if (ms == NULL) | |
2400 | return 0; | |
2401 | ||
2402 | if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (char *) &signo, | |
2403 | sizeof (signo)) != 0) | |
2404 | return 0; | |
2405 | ||
2406 | return signo; | |
2407 | } | |
2408 | ||
2409 | /* Return the set of signals used by the threads library in *SET. */ | |
2410 | ||
2411 | void | |
2412 | lin_thread_get_thread_signals (sigset_t *set) | |
2413 | { | |
2414 | struct sigaction action; | |
2415 | int restart, cancel; | |
2416 | ||
2417 | sigemptyset (set); | |
2418 | ||
2419 | restart = get_signo ("__pthread_sig_restart"); | |
2420 | if (restart == 0) | |
2421 | return; | |
2422 | ||
2423 | cancel = get_signo ("__pthread_sig_cancel"); | |
2424 | if (cancel == 0) | |
2425 | return; | |
2426 | ||
2427 | sigaddset (set, restart); | |
2428 | sigaddset (set, cancel); | |
2429 | ||
2430 | /* The GNU/Linux Threads library makes terminating threads send a | |
2431 | special "cancel" signal instead of SIGCHLD. Make sure we catch | |
2432 | those (to prevent them from terminating GDB itself, which is | |
2433 | likely to be their default action) and treat them the same way as | |
2434 | SIGCHLD. */ | |
2435 | ||
2436 | action.sa_handler = sigchld_handler; | |
2437 | sigemptyset (&action.sa_mask); | |
2438 | action.sa_flags = 0; | |
2439 | sigaction (cancel, &action, NULL); | |
2440 | ||
2441 | /* We block the "cancel" signal throughout this code ... */ | |
2442 | sigaddset (&blocked_mask, cancel); | |
2443 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
2444 | ||
2445 | /* ... except during a sigsuspend. */ | |
2446 | sigdelset (&suspend_mask, cancel); | |
2447 | } |