Commit | Line | Data |
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fb0e1ba7 | 1 | /* Multi-threaded debugging support for Linux (LWP layer). |
4e052eda | 2 | Copyright 2000, 2001 Free Software Foundation, Inc. |
fb0e1ba7 MK |
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 | ||
23 | #include "gdb_assert.h" | |
24 | #include <errno.h> | |
25 | #include <signal.h> | |
26 | #include <sys/ptrace.h> | |
27 | #include "gdb_wait.h" | |
28 | ||
29 | #include "gdbthread.h" | |
30 | #include "inferior.h" | |
31 | #include "target.h" | |
4e052eda | 32 | #include "regcache.h" |
7ca673cd | 33 | #include "gdbcmd.h" |
fb0e1ba7 | 34 | |
7ca673cd | 35 | static int debug_lin_lwp; |
fb0e1ba7 | 36 | extern const char *strsignal (int sig); |
fb0e1ba7 MK |
37 | |
38 | /* On Linux there are no real LWP's. The closest thing to LWP's are | |
39 | processes sharing the same VM space. A multi-threaded process is | |
40 | basically a group of such processes. However, such a grouping is | |
41 | almost entirely a user-space issue; the kernel doesn't enforce such | |
42 | a grouping at all (this might change in the future). In general, | |
43 | we'll rely on the threads library (i.e. the LinuxThreads library) | |
44 | to provide such a grouping. | |
45 | ||
46 | It is perfectly well possible to write a multi-threaded application | |
47 | without the assistance of a threads library, by using the clone | |
48 | system call directly. This module should be able to give some | |
49 | rudimentary support for debugging such applications if developers | |
50 | specify the CLONE_PTRACE flag in the clone system call, and are | |
51 | using Linux 2.4 or above. | |
52 | ||
53 | Note that there are some peculiarities in Linux that affect this | |
54 | code: | |
55 | ||
56 | - In general one should specify the __WCLONE flag to waitpid in | |
3f07c44b MK |
57 | order to make it report events for any of the cloned processes |
58 | (and leave it out for the initial process). However, if a cloned | |
59 | process has exited the exit status is only reported if the | |
60 | __WCLONE flag is absent. Linux 2.4 has a __WALL flag, but we | |
61 | cannot use it since GDB must work on older systems too. | |
fb0e1ba7 MK |
62 | |
63 | - When a traced, cloned process exits and is waited for by the | |
4c8de859 | 64 | debugger, the kernel reassigns it to the original parent and |
fb0e1ba7 MK |
65 | keeps it around as a "zombie". Somehow, the LinuxThreads library |
66 | doesn't notice this, which leads to the "zombie problem": When | |
67 | debugged a multi-threaded process that spawns a lot of threads | |
68 | will run out of processes, even if the threads exit, because the | |
69 | "zombies" stay around. */ | |
70 | ||
71 | /* Structure describing a LWP. */ | |
72 | struct lwp_info | |
73 | { | |
74 | /* The process id of the LWP. This is a combination of the LWP id | |
75 | and overall process id. */ | |
39f77062 | 76 | ptid_t ptid; |
fb0e1ba7 | 77 | |
cacab7c4 MK |
78 | /* Non-zero if this LWP is cloned. In this context "cloned" means |
79 | that the LWP is reporting to its parent using a signal other than | |
80 | SIGCHLD. */ | |
81 | int cloned; | |
82 | ||
fb0e1ba7 MK |
83 | /* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report |
84 | it back yet). */ | |
85 | int signalled; | |
86 | ||
87 | /* Non-zero if this LWP is stopped. */ | |
88 | int stopped; | |
89 | ||
fce0e6e1 MK |
90 | /* Non-zero if this LWP will be/has been resumed. Note that an LWP |
91 | can be marked both as stopped and resumed at the same time. This | |
92 | happens if we try to resume an LWP that has a wait status | |
93 | pending. We shouldn't let the LWP run until that wait status has | |
94 | been processed, but we should not report that wait status if GDB | |
95 | didn't try to let the LWP run. */ | |
96 | int resumed; | |
97 | ||
fb0e1ba7 MK |
98 | /* If non-zero, a pending wait status. */ |
99 | int status; | |
100 | ||
101 | /* Non-zero if we were stepping this LWP. */ | |
102 | int step; | |
103 | ||
104 | /* Next LWP in list. */ | |
105 | struct lwp_info *next; | |
106 | }; | |
107 | ||
108 | /* List of known LWPs. */ | |
109 | static struct lwp_info *lwp_list; | |
110 | ||
111 | /* Number of LWPs in the list. */ | |
112 | static int num_lwps; | |
113 | ||
114 | /* Non-zero if we're running in "threaded" mode. */ | |
115 | static int threaded; | |
116 | \f | |
117 | ||
ca6724c1 KB |
118 | #define GET_LWP(ptid) ptid_get_lwp (ptid) |
119 | #define GET_PID(ptid) ptid_get_pid (ptid) | |
120 | #define is_lwp(ptid) (GET_LWP (ptid) != 0) | |
121 | #define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0) | |
fb0e1ba7 | 122 | |
fb0e1ba7 MK |
123 | /* If the last reported event was a SIGTRAP, this variable is set to |
124 | the process id of the LWP/thread that got it. */ | |
39f77062 | 125 | ptid_t trap_ptid; |
fb0e1ba7 MK |
126 | \f |
127 | ||
128 | /* This module's target-specific operations. */ | |
129 | static struct target_ops lin_lwp_ops; | |
130 | ||
131 | /* The standard child operations. */ | |
132 | extern struct target_ops child_ops; | |
133 | ||
3f07c44b MK |
134 | /* Since we cannot wait (in lin_lwp_wait) for the initial process and |
135 | any cloned processes with a single call to waitpid, we have to use | |
4c8de859 | 136 | the WNOHANG flag and call waitpid in a loop. To optimize |
3f07c44b MK |
137 | things a bit we use `sigsuspend' to wake us up when a process has |
138 | something to report (it will send us a SIGCHLD if it has). To make | |
139 | this work we have to juggle with the signal mask. We save the | |
4c8de859 | 140 | original signal mask such that we can restore it before creating a |
3f07c44b MK |
141 | new process in order to avoid blocking certain signals in the |
142 | inferior. We then block SIGCHLD during the waitpid/sigsuspend | |
143 | loop. */ | |
144 | ||
4c8de859 | 145 | /* Original signal mask. */ |
3f07c44b MK |
146 | static sigset_t normal_mask; |
147 | ||
fb0e1ba7 MK |
148 | /* Signal mask for use with sigsuspend in lin_lwp_wait, initialized in |
149 | _initialize_lin_lwp. */ | |
150 | static sigset_t suspend_mask; | |
3f07c44b MK |
151 | |
152 | /* Signals to block to make that sigsuspend work. */ | |
153 | static sigset_t blocked_mask; | |
fb0e1ba7 MK |
154 | \f |
155 | ||
156 | /* Prototypes for local functions. */ | |
c194fbe1 | 157 | static int stop_wait_callback (struct lwp_info *lp, void *data); |
fb0e1ba7 | 158 | \f |
58eeadba MK |
159 | /* Convert wait status STATUS to a string. Used for printing debug |
160 | messages only. */ | |
fb0e1ba7 | 161 | |
58eeadba MK |
162 | static char * |
163 | status_to_str (int status) | |
164 | { | |
165 | static char buf[64]; | |
166 | ||
167 | if (WIFSTOPPED (status)) | |
168 | snprintf (buf, sizeof (buf), "%s (stopped)", | |
169 | strsignal (WSTOPSIG (status))); | |
170 | else if (WIFSIGNALED (status)) | |
171 | snprintf (buf, sizeof (buf), "%s (terminated)", | |
172 | strsignal (WSTOPSIG (status))); | |
173 | else | |
174 | snprintf (buf, sizeof (buf), "%d (exited)", | |
175 | WEXITSTATUS (status)); | |
176 | ||
177 | return buf; | |
178 | } | |
179 | \f | |
c194fbe1 MK |
180 | /* Initialize the list of LWPs. Note that this module, contrary to |
181 | what GDB's generic threads layer does for its thread list, | |
182 | re-initializes the LWP lists whenever we mourn or detach (which | |
183 | doesn't involve mourning) the inferior. */ | |
fb0e1ba7 MK |
184 | |
185 | static void | |
186 | init_lwp_list (void) | |
187 | { | |
188 | struct lwp_info *lp, *lpnext; | |
189 | ||
190 | for (lp = lwp_list; lp; lp = lpnext) | |
191 | { | |
192 | lpnext = lp->next; | |
b8c9b27d | 193 | xfree (lp); |
fb0e1ba7 MK |
194 | } |
195 | ||
196 | lwp_list = NULL; | |
197 | num_lwps = 0; | |
198 | threaded = 0; | |
199 | } | |
200 | ||
201 | /* Add the LWP specified by PID to the list. If this causes the | |
202 | number of LWPs to become larger than one, go into "threaded" mode. | |
203 | Return a pointer to the structure describing the new LWP. */ | |
204 | ||
205 | static struct lwp_info * | |
39f77062 | 206 | add_lwp (ptid_t ptid) |
fb0e1ba7 MK |
207 | { |
208 | struct lwp_info *lp; | |
209 | ||
39f77062 | 210 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 MK |
211 | |
212 | lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info)); | |
213 | ||
214 | memset (lp, 0, sizeof (struct lwp_info)); | |
215 | ||
39f77062 | 216 | lp->ptid = ptid; |
fb0e1ba7 MK |
217 | |
218 | lp->next = lwp_list; | |
219 | lwp_list = lp; | |
220 | if (++num_lwps > 1) | |
221 | threaded = 1; | |
222 | ||
223 | return lp; | |
224 | } | |
225 | ||
226 | /* Remove the LWP specified by PID from the list. */ | |
227 | ||
228 | static void | |
39f77062 | 229 | delete_lwp (ptid_t ptid) |
fb0e1ba7 MK |
230 | { |
231 | struct lwp_info *lp, *lpprev; | |
232 | ||
233 | lpprev = NULL; | |
234 | ||
235 | for (lp = lwp_list; lp; lpprev = lp, lp = lp->next) | |
39f77062 | 236 | if (ptid_equal (lp->ptid, ptid)) |
fb0e1ba7 MK |
237 | break; |
238 | ||
239 | if (!lp) | |
240 | return; | |
241 | ||
242 | /* We don't go back to "non-threaded" mode if the number of threads | |
243 | becomes less than two. */ | |
244 | num_lwps--; | |
245 | ||
246 | if (lpprev) | |
247 | lpprev->next = lp->next; | |
248 | else | |
249 | lwp_list = lp->next; | |
250 | ||
b8c9b27d | 251 | xfree (lp); |
fb0e1ba7 MK |
252 | } |
253 | ||
254 | /* Return a pointer to the structure describing the LWP corresponding | |
255 | to PID. If no corresponding LWP could be found, return NULL. */ | |
256 | ||
257 | static struct lwp_info * | |
39f77062 | 258 | find_lwp_pid (ptid_t ptid) |
fb0e1ba7 MK |
259 | { |
260 | struct lwp_info *lp; | |
39f77062 | 261 | int lwp; |
fb0e1ba7 | 262 | |
39f77062 KB |
263 | if (is_lwp (ptid)) |
264 | lwp = GET_LWP (ptid); | |
265 | else | |
266 | lwp = GET_PID (ptid); | |
fb0e1ba7 MK |
267 | |
268 | for (lp = lwp_list; lp; lp = lp->next) | |
39f77062 | 269 | if (lwp == GET_LWP (lp->ptid)) |
fb0e1ba7 MK |
270 | return lp; |
271 | ||
272 | return NULL; | |
273 | } | |
274 | ||
275 | /* Call CALLBACK with its second argument set to DATA for every LWP in | |
276 | the list. If CALLBACK returns 1 for a particular LWP, return a | |
277 | pointer to the structure describing that LWP immediately. | |
278 | Otherwise return NULL. */ | |
279 | ||
280 | struct lwp_info * | |
281 | iterate_over_lwps (int (*callback) (struct lwp_info *, void *), void *data) | |
282 | { | |
fce0e6e1 | 283 | struct lwp_info *lp, *lpnext; |
fb0e1ba7 | 284 | |
fce0e6e1 MK |
285 | for (lp = lwp_list; lp; lp = lpnext) |
286 | { | |
287 | lpnext = lp->next; | |
288 | if ((*callback) (lp, data)) | |
289 | return lp; | |
290 | } | |
fb0e1ba7 MK |
291 | |
292 | return NULL; | |
293 | } | |
294 | \f | |
295 | ||
e02bc4cc DS |
296 | /* Implementation of the PREPARE_TO_PROCEED hook for the Linux LWP |
297 | layer. | |
298 | ||
299 | Note that this implementation is potentially redundant now that | |
8849f47d JL |
300 | default_prepare_to_proceed() has been added. |
301 | ||
302 | FIXME This may not support switching threads after Ctrl-C | |
303 | correctly. The default implementation does support this. */ | |
fb0e1ba7 MK |
304 | |
305 | int | |
306 | lin_lwp_prepare_to_proceed (void) | |
307 | { | |
39f77062 KB |
308 | if (! ptid_equal (trap_ptid, null_ptid) |
309 | && ! ptid_equal (inferior_ptid, trap_ptid)) | |
fb0e1ba7 MK |
310 | { |
311 | /* Switched over from TRAP_PID. */ | |
312 | CORE_ADDR stop_pc = read_pc (); | |
313 | CORE_ADDR trap_pc; | |
314 | ||
315 | /* Avoid switching where it wouldn't do any good, i.e. if both | |
316 | threads are at the same breakpoint. */ | |
39f77062 | 317 | trap_pc = read_pc_pid (trap_ptid); |
fb0e1ba7 MK |
318 | if (trap_pc != stop_pc && breakpoint_here_p (trap_pc)) |
319 | { | |
320 | /* User hasn't deleted the breakpoint. Return non-zero, and | |
321 | switch back to TRAP_PID. */ | |
39f77062 | 322 | inferior_ptid = trap_ptid; |
fb0e1ba7 MK |
323 | |
324 | /* FIXME: Is this stuff really necessary? */ | |
325 | flush_cached_frames (); | |
326 | registers_changed (); | |
327 | ||
328 | return 1; | |
329 | } | |
330 | } | |
331 | ||
332 | return 0; | |
333 | } | |
334 | \f | |
335 | ||
336 | #if 0 | |
337 | static void | |
338 | lin_lwp_open (char *args, int from_tty) | |
339 | { | |
340 | push_target (&lin_lwp_ops); | |
341 | } | |
342 | #endif | |
343 | ||
344 | /* Attach to the LWP specified by PID. If VERBOSE is non-zero, print | |
345 | a message telling the user that a new LWP has been added to the | |
346 | process. */ | |
347 | ||
348 | void | |
39f77062 | 349 | lin_lwp_attach_lwp (ptid_t ptid, int verbose) |
fb0e1ba7 MK |
350 | { |
351 | struct lwp_info *lp; | |
352 | ||
39f77062 | 353 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 MK |
354 | |
355 | if (verbose) | |
39f77062 | 356 | printf_filtered ("[New %s]\n", target_pid_to_str (ptid)); |
fb0e1ba7 | 357 | |
c194fbe1 MK |
358 | lp = find_lwp_pid (ptid); |
359 | if (lp == NULL) | |
360 | lp = add_lwp (ptid); | |
361 | ||
cacab7c4 MK |
362 | /* We assume that we're already attached to any LWP that has an |
363 | id equal to the overall process id. */ | |
364 | if (GET_LWP (ptid) != GET_PID (ptid)) | |
c4365b19 | 365 | { |
cacab7c4 MK |
366 | pid_t pid; |
367 | int status; | |
368 | ||
369 | if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0) | |
370 | error ("Can't attach %s: %s", target_pid_to_str (ptid), | |
371 | strerror (errno)); | |
372 | ||
373 | pid = waitpid (GET_LWP (ptid), &status, 0); | |
374 | if (pid == -1 && errno == ECHILD) | |
375 | { | |
376 | /* Try again with __WCLONE to check cloned processes. */ | |
377 | pid = waitpid (GET_LWP (ptid), &status, __WCLONE); | |
378 | lp->cloned = 1; | |
379 | } | |
380 | ||
381 | gdb_assert (pid == GET_LWP (ptid) | |
382 | && WIFSTOPPED (status) && WSTOPSIG (status)); | |
383 | ||
384 | lp->stopped = 1; | |
c4365b19 | 385 | } |
fb0e1ba7 MK |
386 | } |
387 | ||
388 | static void | |
389 | lin_lwp_attach (char *args, int from_tty) | |
390 | { | |
c194fbe1 | 391 | struct lwp_info *lp; |
cacab7c4 MK |
392 | pid_t pid; |
393 | int status; | |
c194fbe1 | 394 | |
fb0e1ba7 MK |
395 | /* FIXME: We should probably accept a list of process id's, and |
396 | attach all of them. */ | |
c194fbe1 MK |
397 | child_ops.to_attach (args, from_tty); |
398 | ||
399 | /* Add the initial process as the first LWP to the list. */ | |
cacab7c4 | 400 | lp = add_lwp (BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid))); |
c194fbe1 MK |
401 | |
402 | /* Make sure the initial process is stopped. The user-level threads | |
403 | layer might want to poke around in the inferior, and that won't | |
404 | work if things haven't stabilized yet. */ | |
cacab7c4 MK |
405 | pid = waitpid (GET_PID (inferior_ptid), &status, 0); |
406 | if (pid == -1 && errno == ECHILD) | |
407 | { | |
408 | warning ("%s is a cloned process", target_pid_to_str (inferior_ptid)); | |
409 | ||
410 | /* Try again with __WCLONE to check cloned processes. */ | |
411 | pid = waitpid (GET_PID (inferior_ptid), &status, __WCLONE); | |
412 | lp->cloned = 1; | |
413 | } | |
414 | ||
415 | gdb_assert (pid == GET_PID (inferior_ptid) | |
416 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP); | |
417 | ||
418 | lp->stopped = 1; | |
c194fbe1 MK |
419 | |
420 | /* Fake the SIGSTOP that core GDB expects. */ | |
421 | lp->status = W_STOPCODE (SIGSTOP); | |
fce0e6e1 | 422 | lp->resumed = 1; |
c194fbe1 MK |
423 | } |
424 | ||
425 | static int | |
426 | detach_callback (struct lwp_info *lp, void *data) | |
427 | { | |
428 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); | |
429 | ||
430 | if (debug_lin_lwp && lp->status) | |
b08cfdb6 | 431 | fprintf_unfiltered (gdb_stdlog, "Pending %s for LWP %ld on detach.\n", |
c194fbe1 MK |
432 | strsignal (WSTOPSIG (lp->status)), GET_LWP (lp->ptid)); |
433 | ||
434 | while (lp->signalled && lp->stopped) | |
435 | { | |
436 | if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, | |
437 | WSTOPSIG (lp->status)) < 0) | |
438 | error ("Can't continue %s: %s", target_pid_to_str (lp->ptid), | |
439 | strerror (errno)); | |
440 | ||
441 | lp->stopped = 0; | |
c4365b19 | 442 | lp->signalled = 0; |
c194fbe1 MK |
443 | lp->status = 0; |
444 | stop_wait_callback (lp, NULL); | |
445 | ||
446 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); | |
447 | } | |
448 | ||
cacab7c4 MK |
449 | /* We don't actually detach from the LWP that has an id equal to the |
450 | overall process id just yet. */ | |
451 | if (GET_LWP (lp->ptid) != GET_PID (lp->ptid)) | |
c194fbe1 MK |
452 | { |
453 | if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0, | |
454 | WSTOPSIG (lp->status)) < 0) | |
455 | error ("Can't detach %s: %s", target_pid_to_str (lp->ptid), | |
456 | strerror (errno)); | |
457 | ||
458 | delete_lwp (lp->ptid); | |
459 | } | |
460 | ||
461 | return 0; | |
fb0e1ba7 MK |
462 | } |
463 | ||
464 | static void | |
465 | lin_lwp_detach (char *args, int from_tty) | |
466 | { | |
c194fbe1 MK |
467 | iterate_over_lwps (detach_callback, NULL); |
468 | ||
cacab7c4 | 469 | /* Only the initial process should be left right now. */ |
c194fbe1 MK |
470 | gdb_assert (num_lwps == 1); |
471 | ||
472 | trap_ptid = null_ptid; | |
473 | ||
474 | /* Destroy LWP info; it's no longer valid. */ | |
475 | init_lwp_list (); | |
476 | ||
477 | /* Restore the original signal mask. */ | |
478 | sigprocmask (SIG_SETMASK, &normal_mask, NULL); | |
479 | sigemptyset (&blocked_mask); | |
480 | ||
01263b57 | 481 | inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid)); |
c194fbe1 | 482 | child_ops.to_detach (args, from_tty); |
fb0e1ba7 MK |
483 | } |
484 | \f | |
485 | ||
486 | struct private_thread_info | |
487 | { | |
488 | int lwpid; | |
489 | }; | |
490 | ||
491 | /* Return non-zero if TP corresponds to the LWP specified by DATA | |
492 | (which is assumed to be a pointer to a `struct lwp_info'. */ | |
493 | ||
494 | static int | |
495 | find_lwp_callback (struct thread_info *tp, void *data) | |
496 | { | |
497 | struct lwp_info *lp = data; | |
498 | ||
39f77062 | 499 | if (tp->private->lwpid == GET_LWP (lp->ptid)) |
fb0e1ba7 MK |
500 | return 1; |
501 | ||
502 | return 0; | |
503 | } | |
504 | ||
505 | /* Resume LP. */ | |
506 | ||
507 | static int | |
508 | resume_callback (struct lwp_info *lp, void *data) | |
509 | { | |
510 | if (lp->stopped && lp->status == 0) | |
511 | { | |
512 | struct thread_info *tp; | |
513 | ||
b1aeb4c5 | 514 | #if 0 |
fb0e1ba7 MK |
515 | /* FIXME: kettenis/2000-08-26: This should really be handled |
516 | properly by core GDB. */ | |
517 | ||
39f77062 | 518 | tp = find_thread_pid (lp->ptid); |
fb0e1ba7 MK |
519 | if (tp == NULL) |
520 | tp = iterate_over_threads (find_lwp_callback, lp); | |
521 | gdb_assert (tp); | |
522 | ||
523 | /* If we were previously stepping the thread, and now continue | |
524 | the thread we must invalidate the stepping range. However, | |
525 | if there is a step_resume breakpoint for this thread, we must | |
526 | preserve the stepping range to make it possible to continue | |
527 | stepping once we hit it. */ | |
528 | if (tp->step_range_end && tp->step_resume_breakpoint == NULL) | |
529 | { | |
530 | gdb_assert (lp->step); | |
531 | tp->step_range_start = tp->step_range_end = 0; | |
532 | } | |
533 | #endif | |
534 | ||
39f77062 | 535 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0); |
fb0e1ba7 MK |
536 | lp->stopped = 0; |
537 | lp->step = 0; | |
538 | } | |
539 | ||
540 | return 0; | |
541 | } | |
542 | ||
fce0e6e1 MK |
543 | static int |
544 | resume_clear_callback (struct lwp_info *lp, void *data) | |
545 | { | |
546 | lp->resumed = 0; | |
547 | return 0; | |
548 | } | |
549 | ||
550 | static int | |
551 | resume_set_callback (struct lwp_info *lp, void *data) | |
552 | { | |
553 | lp->resumed = 1; | |
554 | return 0; | |
555 | } | |
556 | ||
fb0e1ba7 | 557 | static void |
39f77062 | 558 | lin_lwp_resume (ptid_t ptid, int step, enum target_signal signo) |
fb0e1ba7 MK |
559 | { |
560 | struct lwp_info *lp; | |
561 | int resume_all; | |
562 | ||
563 | /* Apparently the interpretation of PID is dependent on STEP: If | |
564 | STEP is non-zero, a specific PID means `step only this process | |
565 | id'. But if STEP is zero, then PID means `continue *all* | |
566 | processes, but give the signal only to this one'. */ | |
39f77062 | 567 | resume_all = (PIDGET (ptid) == -1) || !step; |
fb0e1ba7 | 568 | |
fce0e6e1 MK |
569 | if (resume_all) |
570 | iterate_over_lwps (resume_set_callback, NULL); | |
571 | else | |
572 | iterate_over_lwps (resume_clear_callback, NULL); | |
573 | ||
fb0e1ba7 | 574 | /* If PID is -1, it's the current inferior that should be |
c4365b19 | 575 | handled specially. */ |
39f77062 KB |
576 | if (PIDGET (ptid) == -1) |
577 | ptid = inferior_ptid; | |
fb0e1ba7 | 578 | |
39f77062 | 579 | lp = find_lwp_pid (ptid); |
fb0e1ba7 MK |
580 | if (lp) |
581 | { | |
39f77062 | 582 | ptid = pid_to_ptid (GET_LWP (lp->ptid)); |
fb0e1ba7 | 583 | |
fb0e1ba7 MK |
584 | /* Remember if we're stepping. */ |
585 | lp->step = step; | |
586 | ||
fce0e6e1 MK |
587 | /* Mark this LWP as resumed. */ |
588 | lp->resumed = 1; | |
589 | ||
fb0e1ba7 MK |
590 | /* If we have a pending wait status for this thread, there is no |
591 | point in resuming the process. */ | |
592 | if (lp->status) | |
593 | { | |
594 | /* FIXME: What should we do if we are supposed to continue | |
595 | this thread with a signal? */ | |
596 | gdb_assert (signo == TARGET_SIGNAL_0); | |
597 | return; | |
598 | } | |
40564aca MK |
599 | |
600 | /* Mark LWP as not stopped to prevent it from being continued by | |
601 | resume_callback. */ | |
602 | lp->stopped = 0; | |
fb0e1ba7 MK |
603 | } |
604 | ||
605 | if (resume_all) | |
606 | iterate_over_lwps (resume_callback, NULL); | |
607 | ||
39f77062 | 608 | child_resume (ptid, step, signo); |
fb0e1ba7 MK |
609 | } |
610 | \f | |
611 | ||
612 | /* Send a SIGSTOP to LP. */ | |
613 | ||
614 | static int | |
615 | stop_callback (struct lwp_info *lp, void *data) | |
616 | { | |
617 | if (! lp->stopped && ! lp->signalled) | |
618 | { | |
619 | int ret; | |
620 | ||
39f77062 | 621 | ret = kill (GET_LWP (lp->ptid), SIGSTOP); |
fb0e1ba7 MK |
622 | gdb_assert (ret == 0); |
623 | ||
624 | lp->signalled = 1; | |
625 | gdb_assert (lp->status == 0); | |
626 | } | |
627 | ||
628 | return 0; | |
629 | } | |
630 | ||
de4ca854 MK |
631 | /* Wait until LP is stopped. If DATA is non-null it is interpreted as |
632 | a pointer to a set of signals to be flushed immediately. */ | |
fb0e1ba7 MK |
633 | |
634 | static int | |
635 | stop_wait_callback (struct lwp_info *lp, void *data) | |
636 | { | |
de4ca854 MK |
637 | sigset_t *flush_mask = data; |
638 | ||
fb0e1ba7 MK |
639 | if (! lp->stopped && lp->signalled) |
640 | { | |
641 | pid_t pid; | |
642 | int status; | |
643 | ||
644 | gdb_assert (lp->status == 0); | |
645 | ||
cacab7c4 | 646 | pid = waitpid (GET_LWP (lp->ptid), &status, lp->cloned ? __WCLONE : 0); |
fb0e1ba7 MK |
647 | if (pid == -1 && errno == ECHILD) |
648 | /* OK, the proccess has disappeared. We'll catch the actual | |
3f07c44b | 649 | exit event in lin_lwp_wait. */ |
fb0e1ba7 MK |
650 | return 0; |
651 | ||
39f77062 | 652 | gdb_assert (pid == GET_LWP (lp->ptid)); |
fb0e1ba7 MK |
653 | |
654 | if (WIFEXITED (status) || WIFSIGNALED (status)) | |
655 | { | |
656 | gdb_assert (num_lwps > 1); | |
fb0e1ba7 | 657 | |
39f77062 | 658 | if (in_thread_list (lp->ptid)) |
e6328671 MK |
659 | { |
660 | /* Core GDB cannot deal with us deleting the current | |
661 | thread. */ | |
39f77062 KB |
662 | if (!ptid_equal (lp->ptid, inferior_ptid)) |
663 | delete_thread (lp->ptid); | |
e6328671 | 664 | printf_unfiltered ("[%s exited]\n", |
39f77062 | 665 | target_pid_to_str (lp->ptid)); |
e6328671 | 666 | } |
7ca673cd | 667 | if (debug_lin_lwp) |
9085700c | 668 | fprintf_unfiltered (gdb_stdlog, |
39f77062 | 669 | "%s exited.\n", target_pid_to_str (lp->ptid)); |
7ca673cd | 670 | |
39f77062 | 671 | delete_lwp (lp->ptid); |
fb0e1ba7 MK |
672 | return 0; |
673 | } | |
674 | ||
675 | gdb_assert (WIFSTOPPED (status)); | |
fb0e1ba7 | 676 | |
de4ca854 MK |
677 | /* Ignore any signals in FLUSH_MASK. */ |
678 | if (flush_mask && sigismember (flush_mask, WSTOPSIG (status))) | |
679 | { | |
680 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
681 | return stop_wait_callback (lp, flush_mask); | |
682 | } | |
683 | ||
fb0e1ba7 MK |
684 | if (WSTOPSIG (status) != SIGSTOP) |
685 | { | |
b1aeb4c5 | 686 | if (WSTOPSIG (status) == SIGTRAP) |
fb0e1ba7 MK |
687 | { |
688 | /* If a LWP other than the LWP that we're reporting an | |
689 | event for has hit a GDB breakpoint (as opposed to | |
690 | some random trap signal), then just arrange for it to | |
691 | hit it again later. We don't keep the SIGTRAP status | |
692 | and don't forward the SIGTRAP signal to the LWP. We | |
693 | will handle the current event, eventually we will | |
694 | resume all LWPs, and this one will get its breakpoint | |
695 | trap again. | |
696 | ||
697 | If we do not do this, then we run the risk that the | |
698 | user will delete or disable the breakpoint, but the | |
699 | thread will have already tripped on it. */ | |
7ca673cd | 700 | |
c4365b19 MS |
701 | /* Now resume this LWP and get the SIGSTOP event. */ |
702 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
b1aeb4c5 MS |
703 | if (debug_lin_lwp) |
704 | { | |
705 | fprintf_unfiltered (gdb_stderr, | |
706 | "SWC: Candidate SIGTRAP event in %ld\n", | |
707 | GET_LWP (lp->ptid)); | |
708 | } | |
709 | /* Hold the SIGTRAP for handling by lin_lwp_wait. */ | |
710 | stop_wait_callback (lp, data); | |
711 | /* If there's another event, throw it back into the queue. */ | |
712 | if (lp->status) | |
713 | kill (GET_LWP (lp->ptid), WSTOPSIG (lp->status)); | |
714 | /* Save the sigtrap event. */ | |
715 | lp->status = status; | |
716 | return 0; | |
fb0e1ba7 MK |
717 | } |
718 | else | |
719 | { | |
b1aeb4c5 MS |
720 | /* The thread was stopped with a signal other than |
721 | SIGSTOP, and didn't accidentally trip a breakpoint. */ | |
722 | ||
7ca673cd | 723 | if (debug_lin_lwp) |
b1aeb4c5 MS |
724 | { |
725 | fprintf_unfiltered (gdb_stderr, | |
726 | "SWC: Pending event %d in %ld\n", | |
727 | WSTOPSIG (status), GET_LWP (lp->ptid)); | |
728 | } | |
729 | /* Now resume this LWP and get the SIGSTOP event. */ | |
730 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
7ca673cd | 731 | |
b1aeb4c5 MS |
732 | /* Hold this event/waitstatus while we check to see if |
733 | there are any more (we still want to get that SIGSTOP). */ | |
734 | stop_wait_callback (lp, data); | |
735 | /* If the lp->status field is still empty, use it to hold | |
736 | this event. If not, then this event must be returned | |
737 | to the event queue of the LWP. */ | |
738 | if (lp->status == 0) | |
739 | lp->status = status; | |
740 | else | |
741 | kill (GET_LWP (lp->ptid), WSTOPSIG (status)); | |
742 | return 0; | |
fb0e1ba7 MK |
743 | } |
744 | } | |
745 | else | |
746 | { | |
747 | /* We caught the SIGSTOP that we intended to catch, so | |
748 | there's no SIGSTOP pending. */ | |
b1aeb4c5 | 749 | lp->stopped = 1; |
fb0e1ba7 MK |
750 | lp->signalled = 0; |
751 | } | |
752 | } | |
753 | ||
754 | return 0; | |
755 | } | |
756 | ||
757 | /* Return non-zero if LP has a wait status pending. */ | |
758 | ||
759 | static int | |
760 | status_callback (struct lwp_info *lp, void *data) | |
761 | { | |
fce0e6e1 MK |
762 | /* Only report a pending wait status if we pretend that this has |
763 | indeed been resumed. */ | |
764 | return (lp->status != 0 && lp->resumed); | |
fb0e1ba7 MK |
765 | } |
766 | ||
767 | /* Return non-zero if LP isn't stopped. */ | |
768 | ||
769 | static int | |
770 | running_callback (struct lwp_info *lp, void *data) | |
771 | { | |
772 | return (lp->stopped == 0); | |
773 | } | |
774 | ||
00d4fce6 | 775 | /* Count the LWP's that have had events. */ |
b1aeb4c5 MS |
776 | |
777 | static int | |
778 | count_events_callback (struct lwp_info *lp, void *data) | |
779 | { | |
780 | int *count = data; | |
781 | ||
00d4fce6 MK |
782 | gdb_assert (count != NULL); |
783 | ||
784 | /* Count only LWPs that have a SIGTRAP event pending. */ | |
785 | if (lp->status != 0 | |
786 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) | |
b1aeb4c5 MS |
787 | (*count)++; |
788 | ||
789 | return 0; | |
790 | } | |
791 | ||
00d4fce6 | 792 | /* Select the LWP (if any) that is currently being single-stepped. */ |
b1aeb4c5 MS |
793 | |
794 | static int | |
795 | select_singlestep_lwp_callback (struct lwp_info *lp, void *data) | |
796 | { | |
797 | if (lp->step && lp->status != 0) | |
798 | return 1; | |
799 | else | |
800 | return 0; | |
801 | } | |
802 | ||
00d4fce6 | 803 | /* Select the Nth LWP that has had a SIGTRAP event. */ |
b1aeb4c5 MS |
804 | |
805 | static int | |
806 | select_event_lwp_callback (struct lwp_info *lp, void *data) | |
807 | { | |
808 | int *selector = data; | |
809 | ||
00d4fce6 MK |
810 | gdb_assert (selector != NULL); |
811 | ||
812 | /* Select only LWPs that have a SIGTRAP event pending. */ | |
813 | if (lp->status != 0 | |
814 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) | |
b1aeb4c5 MS |
815 | if ((*selector)-- == 0) |
816 | return 1; | |
817 | ||
818 | return 0; | |
819 | } | |
820 | ||
821 | static int | |
822 | cancel_breakpoints_callback (struct lwp_info *lp, void *data) | |
823 | { | |
824 | struct lwp_info *event_lp = data; | |
825 | ||
00d4fce6 MK |
826 | /* Leave the LWP that has been elected to receive a SIGTRAP alone. */ |
827 | if (lp == event_lp) | |
828 | return 0; | |
829 | ||
830 | /* If a LWP other than the LWP that we're reporting an event for has | |
831 | hit a GDB breakpoint (as opposed to some random trap signal), | |
832 | then just arrange for it to hit it again later. We don't keep | |
833 | the SIGTRAP status and don't forward the SIGTRAP signal to the | |
834 | LWP. We will handle the current event, eventually we will resume | |
835 | all LWPs, and this one will get its breakpoint trap again. | |
836 | ||
837 | If we do not do this, then we run the risk that the user will | |
838 | delete or disable the breakpoint, but the LWP will have already | |
839 | tripped on it. */ | |
840 | ||
841 | if (lp->status != 0 | |
842 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP | |
843 | && breakpoint_inserted_here_p (read_pc_pid (lp->ptid) - | |
844 | DECR_PC_AFTER_BREAK)) | |
b1aeb4c5 MS |
845 | { |
846 | if (debug_lin_lwp) | |
00d4fce6 MK |
847 | fprintf_unfiltered (gdb_stdlog, |
848 | "Push back breakpoint for LWP %ld\n", | |
849 | GET_LWP (lp->ptid)); | |
850 | ||
851 | /* Back up the PC if necessary. */ | |
b1aeb4c5 | 852 | if (DECR_PC_AFTER_BREAK) |
00d4fce6 MK |
853 | write_pc_pid (read_pc_pid (lp->ptid) - DECR_PC_AFTER_BREAK, lp->ptid); |
854 | ||
855 | /* Throw away the SIGTRAP. */ | |
b1aeb4c5 MS |
856 | lp->status = 0; |
857 | } | |
00d4fce6 | 858 | |
b1aeb4c5 MS |
859 | return 0; |
860 | } | |
861 | ||
00d4fce6 | 862 | /* Select one LWP out of those that have events pending. */ |
b1aeb4c5 MS |
863 | |
864 | static void | |
865 | select_event_lwp (struct lwp_info **orig_lp, int *status) | |
866 | { | |
867 | int num_events = 0; | |
868 | int random_selector; | |
869 | struct lwp_info *event_lp; | |
870 | ||
00d4fce6 MK |
871 | /* Record the wait status for the origional LWP. */ |
872 | (*orig_lp)->status = *status; | |
873 | ||
874 | /* Give preference to any LWP that is being single-stepped. */ | |
b1aeb4c5 MS |
875 | event_lp = iterate_over_lwps (select_singlestep_lwp_callback, NULL); |
876 | if (event_lp != NULL) | |
877 | { | |
878 | if (debug_lin_lwp) | |
00d4fce6 MK |
879 | fprintf_unfiltered (gdb_stdlog, |
880 | "Select single-step LWP %ld\n", | |
b1aeb4c5 MS |
881 | GET_LWP (event_lp->ptid)); |
882 | } | |
883 | else | |
884 | { | |
885 | /* No single-stepping LWP. Select one at random, out of those | |
00d4fce6 | 886 | which have had SIGTRAP events. */ |
b1aeb4c5 | 887 | |
00d4fce6 MK |
888 | /* First see how many SIGTRAP events we have. */ |
889 | iterate_over_lwps (count_events_callback, &num_events); | |
b1aeb4c5 | 890 | |
00d4fce6 MK |
891 | /* Now randomly pick a LWP out of those that have had a SIGTRAP. */ |
892 | random_selector = (int) | |
b1aeb4c5 MS |
893 | ((num_events * (double) rand ()) / (RAND_MAX + 1.0)); |
894 | ||
00d4fce6 MK |
895 | if (debug_lin_lwp && num_events > 1) |
896 | fprintf_unfiltered (gdb_stdlog, | |
897 | "Found %d SIGTRAP events, selecting #%d\n", | |
898 | num_events, random_selector); | |
b1aeb4c5 | 899 | |
00d4fce6 MK |
900 | event_lp = iterate_over_lwps (select_event_lwp_callback, |
901 | &random_selector); | |
b1aeb4c5 MS |
902 | } |
903 | ||
904 | if (event_lp != NULL) | |
905 | { | |
00d4fce6 | 906 | /* Switch the event LWP. */ |
b1aeb4c5 MS |
907 | *orig_lp = event_lp; |
908 | *status = event_lp->status; | |
b1aeb4c5 | 909 | } |
00d4fce6 MK |
910 | |
911 | /* Flush the wait status for the event LWP. */ | |
912 | (*orig_lp)->status = 0; | |
b1aeb4c5 MS |
913 | } |
914 | ||
fce0e6e1 MK |
915 | /* Return non-zero if LP has been resumed. */ |
916 | ||
917 | static int | |
918 | resumed_callback (struct lwp_info *lp, void *data) | |
919 | { | |
920 | return lp->resumed; | |
921 | } | |
922 | ||
cacab7c4 MK |
923 | #ifdef CHILD_WAIT |
924 | ||
925 | /* We need to override child_wait to support attaching to cloned | |
926 | processes, since a normal wait (as done by the default version) | |
927 | ignores those processes. */ | |
928 | ||
929 | /* Wait for child PTID to do something. Return id of the child, | |
930 | minus_one_ptid in case of error; store status into *OURSTATUS. */ | |
931 | ||
932 | ptid_t | |
933 | child_wait (ptid_t ptid, struct target_waitstatus *ourstatus) | |
934 | { | |
935 | int save_errno; | |
936 | int status; | |
937 | pid_t pid; | |
938 | ||
939 | do | |
940 | { | |
941 | set_sigint_trap (); /* Causes SIGINT to be passed on to the | |
942 | attached process. */ | |
943 | set_sigio_trap (); | |
944 | ||
945 | pid = waitpid (GET_PID (ptid), &status, 0); | |
946 | if (pid == -1 && errno == ECHILD) | |
947 | /* Try again with __WCLONE to check cloned processes. */ | |
948 | pid = waitpid (GET_PID (ptid), &status, __WCLONE); | |
949 | save_errno = errno; | |
950 | ||
951 | clear_sigio_trap (); | |
952 | clear_sigint_trap (); | |
953 | } | |
954 | while (pid == -1 && errno == EINTR); | |
955 | ||
956 | if (pid == -1) | |
957 | { | |
958 | warning ("Child process unexpectedly missing: %s", strerror (errno)); | |
959 | ||
960 | /* Claim it exited with unknown signal. */ | |
961 | ourstatus->kind = TARGET_WAITKIND_SIGNALLED; | |
962 | ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN; | |
963 | return minus_one_ptid; | |
964 | } | |
965 | ||
966 | store_waitstatus (ourstatus, status); | |
967 | return pid_to_ptid (pid); | |
968 | } | |
969 | ||
970 | #endif | |
971 | ||
39f77062 KB |
972 | static ptid_t |
973 | lin_lwp_wait (ptid_t ptid, struct target_waitstatus *ourstatus) | |
fb0e1ba7 MK |
974 | { |
975 | struct lwp_info *lp = NULL; | |
976 | int options = 0; | |
977 | int status = 0; | |
39f77062 | 978 | pid_t pid = PIDGET (ptid); |
de4ca854 MK |
979 | sigset_t flush_mask; |
980 | ||
981 | sigemptyset (&flush_mask); | |
fb0e1ba7 | 982 | |
3f07c44b MK |
983 | /* Make sure SIGCHLD is blocked. */ |
984 | if (! sigismember (&blocked_mask, SIGCHLD)) | |
985 | { | |
986 | sigaddset (&blocked_mask, SIGCHLD); | |
987 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
988 | } | |
989 | ||
fb0e1ba7 MK |
990 | retry: |
991 | ||
9a973a8f MK |
992 | /* Make sure there is at least one LWP that has been resumed, at |
993 | least if there are any LWPs at all. */ | |
994 | gdb_assert (num_lwps == 0 || iterate_over_lwps (resumed_callback, NULL)); | |
fce0e6e1 | 995 | |
fb0e1ba7 MK |
996 | /* First check if there is a LWP with a wait status pending. */ |
997 | if (pid == -1) | |
998 | { | |
b1aeb4c5 | 999 | /* Any LWP that's been resumed will do. */ |
fb0e1ba7 MK |
1000 | lp = iterate_over_lwps (status_callback, NULL); |
1001 | if (lp) | |
1002 | { | |
fb0e1ba7 MK |
1003 | status = lp->status; |
1004 | lp->status = 0; | |
b1aeb4c5 MS |
1005 | |
1006 | if (debug_lin_lwp && status) | |
58eeadba MK |
1007 | fprintf_unfiltered (gdb_stdlog, |
1008 | "Using pending wait status %s for LWP %ld.\n", | |
1009 | status_to_str (status), GET_LWP (lp->ptid)); | |
fb0e1ba7 MK |
1010 | } |
1011 | ||
1012 | /* But if we don't fine one, we'll have to wait, and check both | |
1013 | cloned and uncloned processes. We start with the cloned | |
1014 | processes. */ | |
1015 | options = __WCLONE | WNOHANG; | |
1016 | } | |
39f77062 | 1017 | else if (is_lwp (ptid)) |
fb0e1ba7 | 1018 | { |
7ca673cd | 1019 | if (debug_lin_lwp) |
9085700c | 1020 | fprintf_unfiltered (gdb_stdlog, |
b08cfdb6 | 1021 | "Waiting for specific LWP %ld.\n", |
ce696e05 | 1022 | GET_LWP (ptid)); |
7ca673cd | 1023 | |
fb0e1ba7 | 1024 | /* We have a specific LWP to check. */ |
39f77062 | 1025 | lp = find_lwp_pid (ptid); |
fb0e1ba7 MK |
1026 | gdb_assert (lp); |
1027 | status = lp->status; | |
1028 | lp->status = 0; | |
7ca673cd | 1029 | |
b1aeb4c5 | 1030 | if (debug_lin_lwp && status) |
58eeadba MK |
1031 | fprintf_unfiltered (gdb_stdlog, |
1032 | "Using pending wait status %s for LWP %ld.\n", | |
1033 | status_to_str (status), GET_LWP (lp->ptid)); | |
fb0e1ba7 MK |
1034 | |
1035 | /* If we have to wait, take into account whether PID is a cloned | |
1036 | process or not. And we have to convert it to something that | |
1037 | the layer beneath us can understand. */ | |
cacab7c4 | 1038 | options = lp->cloned ? __WCLONE : 0; |
39f77062 | 1039 | pid = GET_LWP (ptid); |
fb0e1ba7 MK |
1040 | } |
1041 | ||
1042 | if (status && lp->signalled) | |
1043 | { | |
1044 | /* A pending SIGSTOP may interfere with the normal stream of | |
1045 | events. In a typical case where interference is a problem, | |
1046 | we have a SIGSTOP signal pending for LWP A while | |
1047 | single-stepping it, encounter an event in LWP B, and take the | |
1048 | pending SIGSTOP while trying to stop LWP A. After processing | |
1049 | the event in LWP B, LWP A is continued, and we'll never see | |
1050 | the SIGTRAP associated with the last time we were | |
1051 | single-stepping LWP A. */ | |
1052 | ||
1053 | /* Resume the thread. It should halt immediately returning the | |
1054 | pending SIGSTOP. */ | |
39f77062 KB |
1055 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, |
1056 | TARGET_SIGNAL_0); | |
fb0e1ba7 | 1057 | lp->stopped = 0; |
fce0e6e1 | 1058 | gdb_assert (lp->resumed); |
fb0e1ba7 MK |
1059 | |
1060 | /* This should catch the pending SIGSTOP. */ | |
1061 | stop_wait_callback (lp, NULL); | |
1062 | } | |
1063 | ||
1064 | set_sigint_trap (); /* Causes SIGINT to be passed on to the | |
1065 | attached process. */ | |
1066 | set_sigio_trap (); | |
1067 | ||
1068 | while (status == 0) | |
1069 | { | |
1070 | pid_t lwpid; | |
1071 | ||
1072 | lwpid = waitpid (pid, &status, options); | |
1073 | if (lwpid > 0) | |
1074 | { | |
1075 | gdb_assert (pid == -1 || lwpid == pid); | |
1076 | ||
39f77062 | 1077 | lp = find_lwp_pid (pid_to_ptid (lwpid)); |
fb0e1ba7 MK |
1078 | if (! lp) |
1079 | { | |
39f77062 | 1080 | lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid))); |
cacab7c4 MK |
1081 | if (options & __WCLONE) |
1082 | lp->cloned = 1; | |
1083 | ||
fb0e1ba7 MK |
1084 | if (threaded) |
1085 | { | |
3f07c44b MK |
1086 | gdb_assert (WIFSTOPPED (status) |
1087 | && WSTOPSIG (status) == SIGSTOP); | |
fb0e1ba7 MK |
1088 | lp->signalled = 1; |
1089 | ||
39f77062 | 1090 | if (! in_thread_list (inferior_ptid)) |
fb0e1ba7 | 1091 | { |
39f77062 KB |
1092 | inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid), |
1093 | GET_PID (inferior_ptid)); | |
1094 | add_thread (inferior_ptid); | |
fb0e1ba7 MK |
1095 | } |
1096 | ||
39f77062 | 1097 | add_thread (lp->ptid); |
fb0e1ba7 | 1098 | printf_unfiltered ("[New %s]\n", |
39f77062 | 1099 | target_pid_to_str (lp->ptid)); |
fb0e1ba7 MK |
1100 | } |
1101 | } | |
1102 | ||
1103 | /* Make sure we don't report a TARGET_WAITKIND_EXITED or | |
1104 | TARGET_WAITKIND_SIGNALLED event if there are still LWP's | |
1105 | left in the process. */ | |
1106 | if ((WIFEXITED (status) || WIFSIGNALED (status)) && num_lwps > 1) | |
1107 | { | |
39f77062 | 1108 | if (in_thread_list (lp->ptid)) |
fb0e1ba7 | 1109 | { |
e6328671 | 1110 | /* Core GDB cannot deal with us deleting the current |
fb0e1ba7 | 1111 | thread. */ |
39f77062 KB |
1112 | if (! ptid_equal (lp->ptid, inferior_ptid)) |
1113 | delete_thread (lp->ptid); | |
fb0e1ba7 | 1114 | printf_unfiltered ("[%s exited]\n", |
39f77062 | 1115 | target_pid_to_str (lp->ptid)); |
fb0e1ba7 | 1116 | } |
7ca673cd | 1117 | if (debug_lin_lwp) |
9085700c MS |
1118 | fprintf_unfiltered (gdb_stdlog, |
1119 | "%s exited.\n", | |
39f77062 | 1120 | target_pid_to_str (lp->ptid)); |
7ca673cd | 1121 | |
39f77062 | 1122 | delete_lwp (lp->ptid); |
fb0e1ba7 MK |
1123 | |
1124 | /* Make sure there is at least one thread running. */ | |
1125 | gdb_assert (iterate_over_lwps (running_callback, NULL)); | |
1126 | ||
1127 | /* Discard the event. */ | |
1128 | status = 0; | |
1129 | continue; | |
1130 | } | |
1131 | ||
1132 | /* Make sure we don't report a SIGSTOP that we sent | |
1133 | ourselves in an attempt to stop an LWP. */ | |
1134 | if (lp->signalled && WIFSTOPPED (status) | |
1135 | && WSTOPSIG (status) == SIGSTOP) | |
1136 | { | |
7ca673cd | 1137 | if (debug_lin_lwp) |
9085700c MS |
1138 | fprintf_unfiltered (gdb_stdlog, |
1139 | "Delayed SIGSTOP caught for %s.\n", | |
39f77062 | 1140 | target_pid_to_str (lp->ptid)); |
7ca673cd | 1141 | |
fb0e1ba7 MK |
1142 | /* This is a delayed SIGSTOP. */ |
1143 | lp->signalled = 0; | |
1144 | ||
39f77062 KB |
1145 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, |
1146 | TARGET_SIGNAL_0); | |
fb0e1ba7 | 1147 | lp->stopped = 0; |
fce0e6e1 | 1148 | gdb_assert (lp->resumed); |
fb0e1ba7 MK |
1149 | |
1150 | /* Discard the event. */ | |
1151 | status = 0; | |
1152 | continue; | |
1153 | } | |
1154 | ||
1155 | break; | |
1156 | } | |
1157 | ||
1158 | if (pid == -1) | |
1159 | { | |
1160 | /* Alternate between checking cloned and uncloned processes. */ | |
1161 | options ^= __WCLONE; | |
1162 | ||
1163 | /* And suspend every time we have checked both. */ | |
1164 | if (options & __WCLONE) | |
1165 | sigsuspend (&suspend_mask); | |
1166 | } | |
1167 | ||
1168 | /* We shouldn't end up here unless we want to try again. */ | |
1169 | gdb_assert (status == 0); | |
1170 | } | |
1171 | ||
1172 | clear_sigio_trap (); | |
1173 | clear_sigint_trap (); | |
1174 | ||
1175 | gdb_assert (lp); | |
1176 | ||
1177 | /* Don't report signals that GDB isn't interested in, such as | |
1178 | signals that are neither printed nor stopped upon. Stopping all | |
1179 | threads can be a bit time-consuming so if we want decent | |
1180 | performance with heavily multi-threaded programs, especially when | |
1181 | they're using a high frequency timer, we'd better avoid it if we | |
1182 | can. */ | |
1183 | ||
1184 | if (WIFSTOPPED (status)) | |
1185 | { | |
1186 | int signo = target_signal_from_host (WSTOPSIG (status)); | |
1187 | ||
1188 | if (signal_stop_state (signo) == 0 | |
1189 | && signal_print_state (signo) == 0 | |
1190 | && signal_pass_state (signo) == 1) | |
1191 | { | |
fce0e6e1 MK |
1192 | /* FIMXE: kettenis/2001-06-06: Should we resume all threads |
1193 | here? It is not clear we should. GDB may not expect | |
1194 | other threads to run. On the other hand, not resuming | |
1195 | newly attached threads may cause an unwanted delay in | |
1196 | getting them running. */ | |
c4365b19 | 1197 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, signo); |
fce0e6e1 | 1198 | lp->stopped = 0; |
fb0e1ba7 MK |
1199 | status = 0; |
1200 | goto retry; | |
1201 | } | |
de4ca854 MK |
1202 | |
1203 | if (signo == TARGET_SIGNAL_INT | |
1204 | && signal_pass_state (signo) == 0) | |
1205 | { | |
1206 | /* If ^C/BREAK is typed at the tty/console, SIGINT gets | |
1207 | forwarded to the entire process group, that is, all LWP's | |
1208 | will receive it. Since we only want to report it once, | |
1209 | we try to flush it from all LWPs except this one. */ | |
1210 | sigaddset (&flush_mask, SIGINT); | |
1211 | } | |
fb0e1ba7 MK |
1212 | } |
1213 | ||
1214 | /* This LWP is stopped now. */ | |
1215 | lp->stopped = 1; | |
1216 | ||
b1aeb4c5 | 1217 | if (debug_lin_lwp) |
58eeadba MK |
1218 | fprintf_unfiltered (gdb_stdlog, "Candidate event %s in LWP %ld.\n", |
1219 | status_to_str (status), GET_LWP (lp->ptid)); | |
b1aeb4c5 | 1220 | |
fb0e1ba7 MK |
1221 | /* Now stop all other LWP's ... */ |
1222 | iterate_over_lwps (stop_callback, NULL); | |
1223 | ||
1224 | /* ... and wait until all of them have reported back that they're no | |
1225 | longer running. */ | |
de4ca854 | 1226 | iterate_over_lwps (stop_wait_callback, &flush_mask); |
fb0e1ba7 | 1227 | |
00d4fce6 MK |
1228 | /* If we're not waiting for a specific LWP, choose an event LWP from |
1229 | among those that have had events. Giving equal priority to all | |
1230 | LWPs that have had events helps prevent starvation. */ | |
1231 | if (pid == -1) | |
1232 | select_event_lwp (&lp, &status); | |
b1aeb4c5 | 1233 | |
00d4fce6 MK |
1234 | /* Now that we've selected our final event LWP, cancel any |
1235 | breakpoints in other LWPs that have hit a GDB breakpoint. See | |
1236 | the comment in cancel_breakpoints_callback to find out why. */ | |
1237 | iterate_over_lwps (cancel_breakpoints_callback, lp); | |
b1aeb4c5 | 1238 | |
fb0e1ba7 MK |
1239 | /* If we're not running in "threaded" mode, we'll report the bare |
1240 | process id. */ | |
1241 | ||
1242 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP) | |
b1aeb4c5 MS |
1243 | { |
1244 | trap_ptid = (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid))); | |
1245 | if (debug_lin_lwp) | |
1246 | fprintf_unfiltered (gdb_stdlog, | |
1247 | "LLW: trap_ptid is %ld\n", | |
1248 | GET_LWP (trap_ptid)); | |
1249 | } | |
fb0e1ba7 | 1250 | else |
39f77062 | 1251 | trap_ptid = null_ptid; |
fb0e1ba7 MK |
1252 | |
1253 | store_waitstatus (ourstatus, status); | |
39f77062 | 1254 | return (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid))); |
fb0e1ba7 MK |
1255 | } |
1256 | ||
1257 | static int | |
1258 | kill_callback (struct lwp_info *lp, void *data) | |
1259 | { | |
39f77062 | 1260 | ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0); |
fb0e1ba7 MK |
1261 | return 0; |
1262 | } | |
1263 | ||
1264 | static int | |
1265 | kill_wait_callback (struct lwp_info *lp, void *data) | |
1266 | { | |
1267 | pid_t pid; | |
1268 | ||
1269 | /* We must make sure that there are no pending events (delayed | |
1270 | SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current | |
1271 | program doesn't interfere with any following debugging session. */ | |
1272 | ||
1273 | /* For cloned processes we must check both with __WCLONE and | |
1274 | without, since the exit status of a cloned process isn't reported | |
1275 | with __WCLONE. */ | |
cacab7c4 | 1276 | if (lp->cloned) |
fb0e1ba7 MK |
1277 | { |
1278 | do | |
1279 | { | |
39f77062 | 1280 | pid = waitpid (GET_LWP (lp->ptid), NULL, __WCLONE); |
fb0e1ba7 | 1281 | } |
39f77062 | 1282 | while (pid == GET_LWP (lp->ptid)); |
fb0e1ba7 MK |
1283 | |
1284 | gdb_assert (pid == -1 && errno == ECHILD); | |
1285 | } | |
1286 | ||
1287 | do | |
1288 | { | |
39f77062 | 1289 | pid = waitpid (GET_LWP (lp->ptid), NULL, 0); |
fb0e1ba7 | 1290 | } |
39f77062 | 1291 | while (pid == GET_LWP (lp->ptid)); |
fb0e1ba7 MK |
1292 | |
1293 | gdb_assert (pid == -1 && errno == ECHILD); | |
1294 | return 0; | |
1295 | } | |
1296 | ||
1297 | static void | |
1298 | lin_lwp_kill (void) | |
1299 | { | |
1300 | /* Kill all LWP's ... */ | |
1301 | iterate_over_lwps (kill_callback, NULL); | |
1302 | ||
1303 | /* ... and wait until we've flushed all events. */ | |
1304 | iterate_over_lwps (kill_wait_callback, NULL); | |
1305 | ||
1306 | target_mourn_inferior (); | |
1307 | } | |
1308 | ||
1309 | static void | |
1310 | lin_lwp_create_inferior (char *exec_file, char *allargs, char **env) | |
1311 | { | |
c194fbe1 | 1312 | child_ops.to_create_inferior (exec_file, allargs, env); |
fb0e1ba7 MK |
1313 | } |
1314 | ||
1315 | static void | |
1316 | lin_lwp_mourn_inferior (void) | |
1317 | { | |
c194fbe1 | 1318 | trap_ptid = null_ptid; |
fb0e1ba7 | 1319 | |
c194fbe1 | 1320 | /* Destroy LWP info; it's no longer valid. */ |
fb0e1ba7 MK |
1321 | init_lwp_list (); |
1322 | ||
4c8de859 | 1323 | /* Restore the original signal mask. */ |
3f07c44b MK |
1324 | sigprocmask (SIG_SETMASK, &normal_mask, NULL); |
1325 | sigemptyset (&blocked_mask); | |
1326 | ||
c194fbe1 | 1327 | child_ops.to_mourn_inferior (); |
fb0e1ba7 MK |
1328 | } |
1329 | ||
1330 | static void | |
1331 | lin_lwp_fetch_registers (int regno) | |
1332 | { | |
39f77062 | 1333 | struct cleanup *old_chain = save_inferior_ptid (); |
fb0e1ba7 | 1334 | |
39f77062 KB |
1335 | if (is_lwp (inferior_ptid)) |
1336 | inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid)); | |
fb0e1ba7 MK |
1337 | |
1338 | fetch_inferior_registers (regno); | |
1339 | ||
1340 | do_cleanups (old_chain); | |
1341 | } | |
1342 | ||
1343 | static void | |
1344 | lin_lwp_store_registers (int regno) | |
1345 | { | |
39f77062 | 1346 | struct cleanup *old_chain = save_inferior_ptid (); |
fb0e1ba7 | 1347 | |
39f77062 KB |
1348 | if (is_lwp (inferior_ptid)) |
1349 | inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid)); | |
fb0e1ba7 MK |
1350 | |
1351 | store_inferior_registers (regno); | |
1352 | ||
1353 | do_cleanups (old_chain); | |
1354 | } | |
1355 | ||
1356 | static int | |
1357 | lin_lwp_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write, | |
e5da8f38 | 1358 | struct mem_attrib *attrib, |
fb0e1ba7 MK |
1359 | struct target_ops *target) |
1360 | { | |
39f77062 | 1361 | struct cleanup *old_chain = save_inferior_ptid (); |
fb0e1ba7 MK |
1362 | int xfer; |
1363 | ||
39f77062 KB |
1364 | if (is_lwp (inferior_ptid)) |
1365 | inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid)); | |
fb0e1ba7 | 1366 | |
e5da8f38 | 1367 | xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target); |
fb0e1ba7 MK |
1368 | |
1369 | do_cleanups (old_chain); | |
1370 | return xfer; | |
1371 | } | |
1372 | ||
1373 | static int | |
39f77062 | 1374 | lin_lwp_thread_alive (ptid_t ptid) |
fb0e1ba7 | 1375 | { |
39f77062 | 1376 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 MK |
1377 | |
1378 | errno = 0; | |
39f77062 | 1379 | ptrace (PTRACE_PEEKUSER, GET_LWP (ptid), 0, 0); |
fb0e1ba7 MK |
1380 | if (errno) |
1381 | return 0; | |
1382 | ||
1383 | return 1; | |
1384 | } | |
1385 | ||
1386 | static char * | |
39f77062 | 1387 | lin_lwp_pid_to_str (ptid_t ptid) |
fb0e1ba7 MK |
1388 | { |
1389 | static char buf[64]; | |
1390 | ||
39f77062 | 1391 | if (is_lwp (ptid)) |
fb0e1ba7 | 1392 | { |
b08cfdb6 | 1393 | snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid)); |
fb0e1ba7 MK |
1394 | return buf; |
1395 | } | |
1396 | ||
39f77062 | 1397 | return normal_pid_to_str (ptid); |
fb0e1ba7 MK |
1398 | } |
1399 | ||
1400 | static void | |
1401 | init_lin_lwp_ops (void) | |
1402 | { | |
1403 | #if 0 | |
1404 | lin_lwp_ops.to_open = lin_lwp_open; | |
1405 | #endif | |
1406 | lin_lwp_ops.to_shortname = "lwp-layer"; | |
1407 | lin_lwp_ops.to_longname = "lwp-layer"; | |
1408 | lin_lwp_ops.to_doc = "Low level threads support (LWP layer)"; | |
1409 | lin_lwp_ops.to_attach = lin_lwp_attach; | |
1410 | lin_lwp_ops.to_detach = lin_lwp_detach; | |
1411 | lin_lwp_ops.to_resume = lin_lwp_resume; | |
1412 | lin_lwp_ops.to_wait = lin_lwp_wait; | |
1413 | lin_lwp_ops.to_fetch_registers = lin_lwp_fetch_registers; | |
1414 | lin_lwp_ops.to_store_registers = lin_lwp_store_registers; | |
1415 | lin_lwp_ops.to_xfer_memory = lin_lwp_xfer_memory; | |
1416 | lin_lwp_ops.to_kill = lin_lwp_kill; | |
1417 | lin_lwp_ops.to_create_inferior = lin_lwp_create_inferior; | |
1418 | lin_lwp_ops.to_mourn_inferior = lin_lwp_mourn_inferior; | |
1419 | lin_lwp_ops.to_thread_alive = lin_lwp_thread_alive; | |
1420 | lin_lwp_ops.to_pid_to_str = lin_lwp_pid_to_str; | |
1421 | lin_lwp_ops.to_stratum = thread_stratum; | |
1422 | lin_lwp_ops.to_has_thread_control = tc_schedlock; | |
1423 | lin_lwp_ops.to_magic = OPS_MAGIC; | |
1424 | } | |
1425 | ||
1426 | static void | |
1427 | sigchld_handler (int signo) | |
1428 | { | |
1429 | /* Do nothing. The only reason for this handler is that it allows | |
1430 | us to use sigsuspend in lin_lwp_wait above to wait for the | |
1431 | arrival of a SIGCHLD. */ | |
1432 | } | |
1433 | ||
1434 | void | |
1435 | _initialize_lin_lwp (void) | |
1436 | { | |
1437 | struct sigaction action; | |
fb0e1ba7 MK |
1438 | |
1439 | extern void thread_db_init (struct target_ops *); | |
1440 | ||
1441 | init_lin_lwp_ops (); | |
1442 | add_target (&lin_lwp_ops); | |
1443 | thread_db_init (&lin_lwp_ops); | |
1444 | ||
4c8de859 | 1445 | /* Save the original signal mask. */ |
3f07c44b MK |
1446 | sigprocmask (SIG_SETMASK, NULL, &normal_mask); |
1447 | ||
fb0e1ba7 MK |
1448 | action.sa_handler = sigchld_handler; |
1449 | sigemptyset (&action.sa_mask); | |
1450 | action.sa_flags = 0; | |
1451 | sigaction (SIGCHLD, &action, NULL); | |
1452 | ||
3f07c44b MK |
1453 | /* Make sure we don't block SIGCHLD during a sigsuspend. */ |
1454 | sigprocmask (SIG_SETMASK, NULL, &suspend_mask); | |
fb0e1ba7 | 1455 | sigdelset (&suspend_mask, SIGCHLD); |
3f07c44b MK |
1456 | |
1457 | sigemptyset (&blocked_mask); | |
7ca673cd MS |
1458 | |
1459 | add_show_from_set (add_set_cmd ("lin-lwp", no_class, var_zinteger, | |
1460 | (char *) &debug_lin_lwp, | |
1461 | "Set debugging of linux lwp module.\n\ | |
1462 | Enables printf debugging output.\n", | |
1463 | &setdebuglist), | |
1464 | &showdebuglist); | |
fb0e1ba7 MK |
1465 | } |
1466 | \f | |
1467 | ||
1468 | /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to | |
1469 | the LinuxThreads library and therefore doesn't really belong here. */ | |
1470 | ||
1471 | /* Read variable NAME in the target and return its value if found. | |
1472 | Otherwise return zero. It is assumed that the type of the variable | |
1473 | is `int'. */ | |
1474 | ||
1475 | static int | |
1476 | get_signo (const char *name) | |
1477 | { | |
1478 | struct minimal_symbol *ms; | |
1479 | int signo; | |
1480 | ||
1481 | ms = lookup_minimal_symbol (name, NULL, NULL); | |
1482 | if (ms == NULL) | |
1483 | return 0; | |
1484 | ||
1485 | if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (char *) &signo, | |
1486 | sizeof (signo)) != 0) | |
1487 | return 0; | |
1488 | ||
1489 | return signo; | |
1490 | } | |
1491 | ||
1492 | /* Return the set of signals used by the threads library in *SET. */ | |
1493 | ||
1494 | void | |
1495 | lin_thread_get_thread_signals (sigset_t *set) | |
1496 | { | |
3f07c44b MK |
1497 | struct sigaction action; |
1498 | int restart, cancel; | |
fb0e1ba7 MK |
1499 | |
1500 | sigemptyset (set); | |
1501 | ||
1502 | restart = get_signo ("__pthread_sig_restart"); | |
1503 | if (restart == 0) | |
1504 | return; | |
1505 | ||
1506 | cancel = get_signo ("__pthread_sig_cancel"); | |
1507 | if (cancel == 0) | |
1508 | return; | |
1509 | ||
1510 | sigaddset (set, restart); | |
1511 | sigaddset (set, cancel); | |
3f07c44b MK |
1512 | |
1513 | /* The LinuxThreads library makes terminating threads send a special | |
1514 | "cancel" signal instead of SIGCHLD. Make sure we catch those (to | |
1515 | prevent them from terminating GDB itself, which is likely to be | |
1516 | their default action) and treat them the same way as SIGCHLD. */ | |
1517 | ||
1518 | action.sa_handler = sigchld_handler; | |
1519 | sigemptyset (&action.sa_mask); | |
1520 | action.sa_flags = 0; | |
1521 | sigaction (cancel, &action, NULL); | |
1522 | ||
1523 | /* We block the "cancel" signal throughout this code ... */ | |
1524 | sigaddset (&blocked_mask, cancel); | |
1525 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
1526 | ||
1527 | /* ... except during a sigsuspend. */ | |
1528 | sigdelset (&suspend_mask, cancel); | |
fb0e1ba7 | 1529 | } |