Commit | Line | Data |
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8605d56e | 1 | /* Multi-threaded debugging support for GNU/Linux (LWP layer). |
b3ba1b44 | 2 | Copyright 2000, 2001, 2002, 2003 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" | |
309367d4 | 24 | #include "gdb_string.h" |
fb0e1ba7 MK |
25 | #include <errno.h> |
26 | #include <signal.h> | |
b757528f JJ |
27 | #ifdef HAVE_TKILL_SYSCALL |
28 | #include <unistd.h> | |
29 | #include <sys/syscall.h> | |
30 | #endif | |
fb0e1ba7 MK |
31 | #include <sys/ptrace.h> |
32 | #include "gdb_wait.h" | |
33 | ||
34 | #include "gdbthread.h" | |
35 | #include "inferior.h" | |
36 | #include "target.h" | |
4e052eda | 37 | #include "regcache.h" |
7ca673cd | 38 | #include "gdbcmd.h" |
fb0e1ba7 | 39 | |
7ca673cd | 40 | static int debug_lin_lwp; |
1b84163e | 41 | extern char *strsignal (int sig); |
fb0e1ba7 | 42 | |
0274a8ce MS |
43 | #include "linux-nat.h" |
44 | ||
8605d56e AC |
45 | /* On GNU/Linux there are no real LWP's. The closest thing to LWP's |
46 | are processes sharing the same VM space. A multi-threaded process | |
47 | is basically a group of such processes. However, such a grouping | |
48 | is almost entirely a user-space issue; the kernel doesn't enforce | |
49 | such a grouping at all (this might change in the future). In | |
50 | general, we'll rely on the threads library (i.e. the GNU/Linux | |
51 | Threads library) to provide such a grouping. | |
fb0e1ba7 MK |
52 | |
53 | It is perfectly well possible to write a multi-threaded application | |
54 | without the assistance of a threads library, by using the clone | |
55 | system call directly. This module should be able to give some | |
56 | rudimentary support for debugging such applications if developers | |
57 | specify the CLONE_PTRACE flag in the clone system call, and are | |
8605d56e | 58 | using the Linux kernel 2.4 or above. |
fb0e1ba7 | 59 | |
8605d56e AC |
60 | Note that there are some peculiarities in GNU/Linux that affect |
61 | this code: | |
fb0e1ba7 MK |
62 | |
63 | - In general one should specify the __WCLONE flag to waitpid in | |
3f07c44b MK |
64 | order to make it report events for any of the cloned processes |
65 | (and leave it out for the initial process). However, if a cloned | |
66 | process has exited the exit status is only reported if the | |
8605d56e AC |
67 | __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but |
68 | we cannot use it since GDB must work on older systems too. | |
fb0e1ba7 MK |
69 | |
70 | - When a traced, cloned process exits and is waited for by the | |
4c8de859 | 71 | debugger, the kernel reassigns it to the original parent and |
8605d56e AC |
72 | keeps it around as a "zombie". Somehow, the GNU/Linux Threads |
73 | library doesn't notice this, which leads to the "zombie problem": | |
74 | When debugged a multi-threaded process that spawns a lot of | |
75 | threads will run out of processes, even if the threads exit, | |
76 | because the "zombies" stay around. */ | |
fb0e1ba7 | 77 | |
fb0e1ba7 MK |
78 | /* List of known LWPs. */ |
79 | static struct lwp_info *lwp_list; | |
80 | ||
81 | /* Number of LWPs in the list. */ | |
82 | static int num_lwps; | |
83 | ||
84 | /* Non-zero if we're running in "threaded" mode. */ | |
85 | static int threaded; | |
86 | \f | |
87 | ||
ca6724c1 KB |
88 | #define GET_LWP(ptid) ptid_get_lwp (ptid) |
89 | #define GET_PID(ptid) ptid_get_pid (ptid) | |
90 | #define is_lwp(ptid) (GET_LWP (ptid) != 0) | |
91 | #define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0) | |
fb0e1ba7 | 92 | |
fb0e1ba7 MK |
93 | /* If the last reported event was a SIGTRAP, this variable is set to |
94 | the process id of the LWP/thread that got it. */ | |
39f77062 | 95 | ptid_t trap_ptid; |
fb0e1ba7 MK |
96 | \f |
97 | ||
98 | /* This module's target-specific operations. */ | |
99 | static struct target_ops lin_lwp_ops; | |
100 | ||
101 | /* The standard child operations. */ | |
102 | extern struct target_ops child_ops; | |
103 | ||
3f07c44b MK |
104 | /* Since we cannot wait (in lin_lwp_wait) for the initial process and |
105 | any cloned processes with a single call to waitpid, we have to use | |
4c8de859 | 106 | the WNOHANG flag and call waitpid in a loop. To optimize |
3f07c44b MK |
107 | things a bit we use `sigsuspend' to wake us up when a process has |
108 | something to report (it will send us a SIGCHLD if it has). To make | |
109 | this work we have to juggle with the signal mask. We save the | |
4c8de859 | 110 | original signal mask such that we can restore it before creating a |
3f07c44b MK |
111 | new process in order to avoid blocking certain signals in the |
112 | inferior. We then block SIGCHLD during the waitpid/sigsuspend | |
113 | loop. */ | |
114 | ||
4c8de859 | 115 | /* Original signal mask. */ |
3f07c44b MK |
116 | static sigset_t normal_mask; |
117 | ||
fb0e1ba7 MK |
118 | /* Signal mask for use with sigsuspend in lin_lwp_wait, initialized in |
119 | _initialize_lin_lwp. */ | |
120 | static sigset_t suspend_mask; | |
3f07c44b MK |
121 | |
122 | /* Signals to block to make that sigsuspend work. */ | |
123 | static sigset_t blocked_mask; | |
fb0e1ba7 MK |
124 | \f |
125 | ||
126 | /* Prototypes for local functions. */ | |
c194fbe1 | 127 | static int stop_wait_callback (struct lwp_info *lp, void *data); |
b757528f | 128 | static int lin_lwp_thread_alive (ptid_t ptid); |
fb0e1ba7 | 129 | \f |
58eeadba MK |
130 | /* Convert wait status STATUS to a string. Used for printing debug |
131 | messages only. */ | |
fb0e1ba7 | 132 | |
58eeadba MK |
133 | static char * |
134 | status_to_str (int status) | |
135 | { | |
136 | static char buf[64]; | |
137 | ||
138 | if (WIFSTOPPED (status)) | |
139 | snprintf (buf, sizeof (buf), "%s (stopped)", | |
140 | strsignal (WSTOPSIG (status))); | |
141 | else if (WIFSIGNALED (status)) | |
142 | snprintf (buf, sizeof (buf), "%s (terminated)", | |
143 | strsignal (WSTOPSIG (status))); | |
144 | else | |
6949171e | 145 | snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status)); |
58eeadba MK |
146 | |
147 | return buf; | |
148 | } | |
149 | \f | |
c194fbe1 MK |
150 | /* Initialize the list of LWPs. Note that this module, contrary to |
151 | what GDB's generic threads layer does for its thread list, | |
152 | re-initializes the LWP lists whenever we mourn or detach (which | |
153 | doesn't involve mourning) the inferior. */ | |
fb0e1ba7 MK |
154 | |
155 | static void | |
156 | init_lwp_list (void) | |
157 | { | |
158 | struct lwp_info *lp, *lpnext; | |
159 | ||
160 | for (lp = lwp_list; lp; lp = lpnext) | |
161 | { | |
162 | lpnext = lp->next; | |
b8c9b27d | 163 | xfree (lp); |
fb0e1ba7 MK |
164 | } |
165 | ||
166 | lwp_list = NULL; | |
167 | num_lwps = 0; | |
168 | threaded = 0; | |
169 | } | |
170 | ||
171 | /* Add the LWP specified by PID to the list. If this causes the | |
172 | number of LWPs to become larger than one, go into "threaded" mode. | |
173 | Return a pointer to the structure describing the new LWP. */ | |
174 | ||
175 | static struct lwp_info * | |
39f77062 | 176 | add_lwp (ptid_t ptid) |
fb0e1ba7 MK |
177 | { |
178 | struct lwp_info *lp; | |
179 | ||
39f77062 | 180 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 MK |
181 | |
182 | lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info)); | |
183 | ||
184 | memset (lp, 0, sizeof (struct lwp_info)); | |
185 | ||
39f77062 | 186 | lp->ptid = ptid; |
fb0e1ba7 MK |
187 | |
188 | lp->next = lwp_list; | |
189 | lwp_list = lp; | |
190 | if (++num_lwps > 1) | |
191 | threaded = 1; | |
192 | ||
193 | return lp; | |
194 | } | |
195 | ||
196 | /* Remove the LWP specified by PID from the list. */ | |
197 | ||
198 | static void | |
39f77062 | 199 | delete_lwp (ptid_t ptid) |
fb0e1ba7 MK |
200 | { |
201 | struct lwp_info *lp, *lpprev; | |
202 | ||
203 | lpprev = NULL; | |
204 | ||
205 | for (lp = lwp_list; lp; lpprev = lp, lp = lp->next) | |
39f77062 | 206 | if (ptid_equal (lp->ptid, ptid)) |
fb0e1ba7 MK |
207 | break; |
208 | ||
209 | if (!lp) | |
210 | return; | |
211 | ||
212 | /* We don't go back to "non-threaded" mode if the number of threads | |
213 | becomes less than two. */ | |
214 | num_lwps--; | |
215 | ||
216 | if (lpprev) | |
217 | lpprev->next = lp->next; | |
218 | else | |
219 | lwp_list = lp->next; | |
220 | ||
b8c9b27d | 221 | xfree (lp); |
fb0e1ba7 MK |
222 | } |
223 | ||
224 | /* Return a pointer to the structure describing the LWP corresponding | |
225 | to PID. If no corresponding LWP could be found, return NULL. */ | |
226 | ||
227 | static struct lwp_info * | |
39f77062 | 228 | find_lwp_pid (ptid_t ptid) |
fb0e1ba7 MK |
229 | { |
230 | struct lwp_info *lp; | |
39f77062 | 231 | int lwp; |
fb0e1ba7 | 232 | |
39f77062 KB |
233 | if (is_lwp (ptid)) |
234 | lwp = GET_LWP (ptid); | |
235 | else | |
236 | lwp = GET_PID (ptid); | |
fb0e1ba7 MK |
237 | |
238 | for (lp = lwp_list; lp; lp = lp->next) | |
39f77062 | 239 | if (lwp == GET_LWP (lp->ptid)) |
fb0e1ba7 MK |
240 | return lp; |
241 | ||
242 | return NULL; | |
243 | } | |
244 | ||
245 | /* Call CALLBACK with its second argument set to DATA for every LWP in | |
246 | the list. If CALLBACK returns 1 for a particular LWP, return a | |
247 | pointer to the structure describing that LWP immediately. | |
248 | Otherwise return NULL. */ | |
249 | ||
250 | struct lwp_info * | |
251 | iterate_over_lwps (int (*callback) (struct lwp_info *, void *), void *data) | |
252 | { | |
fce0e6e1 | 253 | struct lwp_info *lp, *lpnext; |
fb0e1ba7 | 254 | |
fce0e6e1 MK |
255 | for (lp = lwp_list; lp; lp = lpnext) |
256 | { | |
257 | lpnext = lp->next; | |
258 | if ((*callback) (lp, data)) | |
259 | return lp; | |
260 | } | |
fb0e1ba7 MK |
261 | |
262 | return NULL; | |
263 | } | |
264 | \f | |
265 | ||
fb0e1ba7 MK |
266 | #if 0 |
267 | static void | |
268 | lin_lwp_open (char *args, int from_tty) | |
269 | { | |
270 | push_target (&lin_lwp_ops); | |
271 | } | |
272 | #endif | |
273 | ||
274 | /* Attach to the LWP specified by PID. If VERBOSE is non-zero, print | |
275 | a message telling the user that a new LWP has been added to the | |
276 | process. */ | |
277 | ||
278 | void | |
39f77062 | 279 | lin_lwp_attach_lwp (ptid_t ptid, int verbose) |
fb0e1ba7 MK |
280 | { |
281 | struct lwp_info *lp; | |
282 | ||
39f77062 | 283 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 | 284 | |
da9c7185 KB |
285 | /* Make sure SIGCHLD is blocked. We don't want SIGCHLD events |
286 | to interrupt either the ptrace() or waitpid() calls below. */ | |
6949171e | 287 | if (!sigismember (&blocked_mask, SIGCHLD)) |
da9c7185 KB |
288 | { |
289 | sigaddset (&blocked_mask, SIGCHLD); | |
290 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
291 | } | |
292 | ||
fb0e1ba7 | 293 | if (verbose) |
39f77062 | 294 | printf_filtered ("[New %s]\n", target_pid_to_str (ptid)); |
fb0e1ba7 | 295 | |
c194fbe1 MK |
296 | lp = find_lwp_pid (ptid); |
297 | if (lp == NULL) | |
298 | lp = add_lwp (ptid); | |
299 | ||
cacab7c4 MK |
300 | /* We assume that we're already attached to any LWP that has an |
301 | id equal to the overall process id. */ | |
302 | if (GET_LWP (ptid) != GET_PID (ptid)) | |
c4365b19 | 303 | { |
cacab7c4 MK |
304 | pid_t pid; |
305 | int status; | |
306 | ||
307 | if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0) | |
308 | error ("Can't attach %s: %s", target_pid_to_str (ptid), | |
dc672865 | 309 | safe_strerror (errno)); |
cacab7c4 | 310 | |
9fe7d6bf | 311 | if (debug_lin_lwp) |
6949171e JJ |
312 | fprintf_unfiltered (gdb_stdlog, |
313 | "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n", | |
9fe7d6bf MS |
314 | target_pid_to_str (ptid)); |
315 | ||
cacab7c4 MK |
316 | pid = waitpid (GET_LWP (ptid), &status, 0); |
317 | if (pid == -1 && errno == ECHILD) | |
318 | { | |
319 | /* Try again with __WCLONE to check cloned processes. */ | |
320 | pid = waitpid (GET_LWP (ptid), &status, __WCLONE); | |
321 | lp->cloned = 1; | |
322 | } | |
323 | ||
324 | gdb_assert (pid == GET_LWP (ptid) | |
325 | && WIFSTOPPED (status) && WSTOPSIG (status)); | |
326 | ||
4de4c07c DJ |
327 | child_post_attach (pid); |
328 | ||
cacab7c4 | 329 | lp->stopped = 1; |
9fe7d6bf MS |
330 | |
331 | if (debug_lin_lwp) | |
332 | { | |
333 | fprintf_unfiltered (gdb_stdlog, | |
334 | "LLAL: waitpid %s received %s\n", | |
6949171e | 335 | target_pid_to_str (ptid), |
9fe7d6bf MS |
336 | status_to_str (status)); |
337 | } | |
c4365b19 | 338 | } |
da9c7185 KB |
339 | else |
340 | { | |
341 | /* We assume that the LWP representing the original process | |
6949171e JJ |
342 | is already stopped. Mark it as stopped in the data structure |
343 | that the lin-lwp layer uses to keep track of threads. Note | |
344 | that this won't have already been done since the main thread | |
345 | will have, we assume, been stopped by an attach from a | |
346 | different layer. */ | |
da9c7185 KB |
347 | lp->stopped = 1; |
348 | } | |
fb0e1ba7 MK |
349 | } |
350 | ||
351 | static void | |
352 | lin_lwp_attach (char *args, int from_tty) | |
353 | { | |
c194fbe1 | 354 | struct lwp_info *lp; |
cacab7c4 MK |
355 | pid_t pid; |
356 | int status; | |
c194fbe1 | 357 | |
fb0e1ba7 MK |
358 | /* FIXME: We should probably accept a list of process id's, and |
359 | attach all of them. */ | |
c194fbe1 MK |
360 | child_ops.to_attach (args, from_tty); |
361 | ||
362 | /* Add the initial process as the first LWP to the list. */ | |
cacab7c4 | 363 | lp = add_lwp (BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid))); |
c194fbe1 MK |
364 | |
365 | /* Make sure the initial process is stopped. The user-level threads | |
366 | layer might want to poke around in the inferior, and that won't | |
367 | work if things haven't stabilized yet. */ | |
cacab7c4 MK |
368 | pid = waitpid (GET_PID (inferior_ptid), &status, 0); |
369 | if (pid == -1 && errno == ECHILD) | |
370 | { | |
371 | warning ("%s is a cloned process", target_pid_to_str (inferior_ptid)); | |
372 | ||
373 | /* Try again with __WCLONE to check cloned processes. */ | |
374 | pid = waitpid (GET_PID (inferior_ptid), &status, __WCLONE); | |
375 | lp->cloned = 1; | |
376 | } | |
377 | ||
378 | gdb_assert (pid == GET_PID (inferior_ptid) | |
379 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP); | |
380 | ||
381 | lp->stopped = 1; | |
c194fbe1 MK |
382 | |
383 | /* Fake the SIGSTOP that core GDB expects. */ | |
384 | lp->status = W_STOPCODE (SIGSTOP); | |
fce0e6e1 | 385 | lp->resumed = 1; |
9fe7d6bf MS |
386 | if (debug_lin_lwp) |
387 | { | |
388 | fprintf_unfiltered (gdb_stdlog, | |
6949171e | 389 | "LLA: waitpid %ld, faking SIGSTOP\n", (long) pid); |
9fe7d6bf | 390 | } |
c194fbe1 MK |
391 | } |
392 | ||
393 | static int | |
394 | detach_callback (struct lwp_info *lp, void *data) | |
395 | { | |
396 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); | |
397 | ||
398 | if (debug_lin_lwp && lp->status) | |
9fe7d6bf | 399 | fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n", |
6949171e | 400 | strsignal (WSTOPSIG (lp->status)), |
9fe7d6bf | 401 | target_pid_to_str (lp->ptid)); |
c194fbe1 MK |
402 | |
403 | while (lp->signalled && lp->stopped) | |
404 | { | |
9fe7d6bf | 405 | errno = 0; |
c194fbe1 MK |
406 | if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, |
407 | WSTOPSIG (lp->status)) < 0) | |
408 | error ("Can't continue %s: %s", target_pid_to_str (lp->ptid), | |
dc672865 | 409 | safe_strerror (errno)); |
c194fbe1 | 410 | |
9fe7d6bf | 411 | if (debug_lin_lwp) |
6949171e | 412 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
413 | "DC: PTRACE_CONTINUE (%s, 0, %s) (OK)\n", |
414 | target_pid_to_str (lp->ptid), | |
6949171e | 415 | status_to_str (lp->status)); |
9fe7d6bf | 416 | |
c194fbe1 | 417 | lp->stopped = 0; |
c4365b19 | 418 | lp->signalled = 0; |
c194fbe1 | 419 | lp->status = 0; |
bfb39158 DJ |
420 | /* FIXME drow/2003-08-26: There was a call to stop_wait_callback |
421 | here. But since lp->signalled was cleared above, | |
422 | stop_wait_callback didn't do anything; the process was left | |
423 | running. Shouldn't we be waiting for it to stop? | |
424 | I've removed the call, since stop_wait_callback now does do | |
425 | something when called with lp->signalled == 0. */ | |
c194fbe1 MK |
426 | |
427 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); | |
428 | } | |
429 | ||
cacab7c4 MK |
430 | /* We don't actually detach from the LWP that has an id equal to the |
431 | overall process id just yet. */ | |
432 | if (GET_LWP (lp->ptid) != GET_PID (lp->ptid)) | |
c194fbe1 | 433 | { |
9fe7d6bf | 434 | errno = 0; |
c194fbe1 MK |
435 | if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0, |
436 | WSTOPSIG (lp->status)) < 0) | |
437 | error ("Can't detach %s: %s", target_pid_to_str (lp->ptid), | |
dc672865 | 438 | safe_strerror (errno)); |
c194fbe1 | 439 | |
9fe7d6bf MS |
440 | if (debug_lin_lwp) |
441 | fprintf_unfiltered (gdb_stdlog, | |
442 | "PTRACE_DETACH (%s, %s, 0) (OK)\n", | |
6949171e | 443 | target_pid_to_str (lp->ptid), |
9fe7d6bf MS |
444 | strsignal (WSTOPSIG (lp->status))); |
445 | ||
c194fbe1 MK |
446 | delete_lwp (lp->ptid); |
447 | } | |
448 | ||
449 | return 0; | |
fb0e1ba7 MK |
450 | } |
451 | ||
452 | static void | |
453 | lin_lwp_detach (char *args, int from_tty) | |
454 | { | |
c194fbe1 MK |
455 | iterate_over_lwps (detach_callback, NULL); |
456 | ||
cacab7c4 | 457 | /* Only the initial process should be left right now. */ |
c194fbe1 MK |
458 | gdb_assert (num_lwps == 1); |
459 | ||
460 | trap_ptid = null_ptid; | |
461 | ||
462 | /* Destroy LWP info; it's no longer valid. */ | |
463 | init_lwp_list (); | |
464 | ||
465 | /* Restore the original signal mask. */ | |
466 | sigprocmask (SIG_SETMASK, &normal_mask, NULL); | |
467 | sigemptyset (&blocked_mask); | |
468 | ||
01263b57 | 469 | inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid)); |
c194fbe1 | 470 | child_ops.to_detach (args, from_tty); |
fb0e1ba7 MK |
471 | } |
472 | \f | |
473 | ||
fb0e1ba7 MK |
474 | /* Resume LP. */ |
475 | ||
476 | static int | |
477 | resume_callback (struct lwp_info *lp, void *data) | |
478 | { | |
479 | if (lp->stopped && lp->status == 0) | |
480 | { | |
481 | struct thread_info *tp; | |
482 | ||
39f77062 | 483 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0); |
9fe7d6bf | 484 | if (debug_lin_lwp) |
6949171e | 485 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
486 | "RC: PTRACE_CONT %s, 0, 0 (resume sibling)\n", |
487 | target_pid_to_str (lp->ptid)); | |
fb0e1ba7 MK |
488 | lp->stopped = 0; |
489 | lp->step = 0; | |
490 | } | |
491 | ||
492 | return 0; | |
493 | } | |
494 | ||
fce0e6e1 MK |
495 | static int |
496 | resume_clear_callback (struct lwp_info *lp, void *data) | |
497 | { | |
498 | lp->resumed = 0; | |
499 | return 0; | |
500 | } | |
501 | ||
502 | static int | |
503 | resume_set_callback (struct lwp_info *lp, void *data) | |
504 | { | |
505 | lp->resumed = 1; | |
506 | return 0; | |
507 | } | |
508 | ||
fb0e1ba7 | 509 | static void |
39f77062 | 510 | lin_lwp_resume (ptid_t ptid, int step, enum target_signal signo) |
fb0e1ba7 MK |
511 | { |
512 | struct lwp_info *lp; | |
513 | int resume_all; | |
514 | ||
2a4b7c45 DJ |
515 | /* A specific PTID means `step only this process id'. */ |
516 | resume_all = (PIDGET (ptid) == -1); | |
fb0e1ba7 | 517 | |
fce0e6e1 MK |
518 | if (resume_all) |
519 | iterate_over_lwps (resume_set_callback, NULL); | |
520 | else | |
521 | iterate_over_lwps (resume_clear_callback, NULL); | |
522 | ||
fb0e1ba7 | 523 | /* If PID is -1, it's the current inferior that should be |
c4365b19 | 524 | handled specially. */ |
39f77062 KB |
525 | if (PIDGET (ptid) == -1) |
526 | ptid = inferior_ptid; | |
fb0e1ba7 | 527 | |
39f77062 | 528 | lp = find_lwp_pid (ptid); |
fb0e1ba7 MK |
529 | if (lp) |
530 | { | |
39f77062 | 531 | ptid = pid_to_ptid (GET_LWP (lp->ptid)); |
fb0e1ba7 | 532 | |
fb0e1ba7 MK |
533 | /* Remember if we're stepping. */ |
534 | lp->step = step; | |
535 | ||
fce0e6e1 MK |
536 | /* Mark this LWP as resumed. */ |
537 | lp->resumed = 1; | |
538 | ||
fb0e1ba7 MK |
539 | /* If we have a pending wait status for this thread, there is no |
540 | point in resuming the process. */ | |
541 | if (lp->status) | |
542 | { | |
543 | /* FIXME: What should we do if we are supposed to continue | |
6949171e | 544 | this thread with a signal? */ |
fb0e1ba7 MK |
545 | gdb_assert (signo == TARGET_SIGNAL_0); |
546 | return; | |
547 | } | |
40564aca MK |
548 | |
549 | /* Mark LWP as not stopped to prevent it from being continued by | |
6949171e | 550 | resume_callback. */ |
40564aca | 551 | lp->stopped = 0; |
fb0e1ba7 MK |
552 | } |
553 | ||
554 | if (resume_all) | |
555 | iterate_over_lwps (resume_callback, NULL); | |
556 | ||
39f77062 | 557 | child_resume (ptid, step, signo); |
9fe7d6bf MS |
558 | if (debug_lin_lwp) |
559 | fprintf_unfiltered (gdb_stdlog, | |
560 | "LLR: %s %s, %s (resume event thread)\n", | |
561 | step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT", | |
562 | target_pid_to_str (ptid), | |
563 | signo ? strsignal (signo) : "0"); | |
fb0e1ba7 MK |
564 | } |
565 | \f | |
566 | ||
b757528f JJ |
567 | /* Issue kill to specified lwp. */ |
568 | ||
569 | static int tkill_failed; | |
570 | ||
571 | static int | |
572 | kill_lwp (int lwpid, int signo) | |
573 | { | |
574 | errno = 0; | |
575 | ||
576 | /* Use tkill, if possible, in case we are using nptl threads. If tkill | |
577 | fails, then we are not using nptl threads and we should be using kill. */ | |
578 | ||
579 | #ifdef HAVE_TKILL_SYSCALL | |
580 | if (!tkill_failed) | |
581 | { | |
582 | int ret = syscall (__NR_tkill, lwpid, signo); | |
583 | if (errno != ENOSYS) | |
584 | return ret; | |
585 | errno = 0; | |
586 | tkill_failed = 1; | |
587 | } | |
588 | #endif | |
589 | ||
590 | return kill (lwpid, signo); | |
591 | } | |
592 | ||
c64bd0ce DJ |
593 | /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has |
594 | exited. */ | |
595 | ||
596 | static int | |
597 | wait_lwp (struct lwp_info *lp) | |
598 | { | |
599 | pid_t pid; | |
600 | int status; | |
601 | int thread_dead = 0; | |
602 | ||
603 | gdb_assert (!lp->stopped); | |
604 | gdb_assert (lp->status == 0); | |
605 | ||
606 | pid = waitpid (GET_LWP (lp->ptid), &status, 0); | |
607 | if (pid == -1 && errno == ECHILD) | |
608 | { | |
609 | pid = waitpid (GET_LWP (lp->ptid), &status, __WCLONE); | |
610 | if (pid == -1 && errno == ECHILD) | |
611 | { | |
612 | /* The thread has previously exited. We need to delete it now | |
613 | because in the case of NPTL threads, there won't be an | |
614 | exit event unless it is the main thread. */ | |
615 | thread_dead = 1; | |
616 | if (debug_lin_lwp) | |
617 | fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n", | |
618 | target_pid_to_str (lp->ptid)); | |
619 | } | |
620 | } | |
621 | ||
622 | if (!thread_dead) | |
623 | { | |
624 | gdb_assert (pid == GET_LWP (lp->ptid)); | |
625 | ||
626 | if (debug_lin_lwp) | |
627 | { | |
628 | fprintf_unfiltered (gdb_stdlog, | |
629 | "WL: waitpid %s received %s\n", | |
630 | target_pid_to_str (lp->ptid), | |
631 | status_to_str (status)); | |
632 | } | |
633 | } | |
634 | ||
635 | /* Check if the thread has exited. */ | |
636 | if (WIFEXITED (status) || WIFSIGNALED (status)) | |
637 | { | |
638 | thread_dead = 1; | |
639 | if (debug_lin_lwp) | |
640 | fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n", | |
641 | target_pid_to_str (lp->ptid)); | |
642 | } | |
643 | ||
644 | if (thread_dead) | |
645 | { | |
646 | if (in_thread_list (lp->ptid)) | |
647 | { | |
648 | /* Core GDB cannot deal with us deleting the current thread. */ | |
649 | if (!ptid_equal (lp->ptid, inferior_ptid)) | |
650 | delete_thread (lp->ptid); | |
651 | printf_unfiltered ("[%s exited]\n", | |
652 | target_pid_to_str (lp->ptid)); | |
653 | } | |
654 | ||
655 | delete_lwp (lp->ptid); | |
656 | return 0; | |
657 | } | |
658 | ||
659 | gdb_assert (WIFSTOPPED (status)); | |
660 | ||
661 | return status; | |
662 | } | |
663 | ||
fb0e1ba7 MK |
664 | /* Send a SIGSTOP to LP. */ |
665 | ||
666 | static int | |
667 | stop_callback (struct lwp_info *lp, void *data) | |
668 | { | |
6949171e | 669 | if (!lp->stopped && !lp->signalled) |
fb0e1ba7 MK |
670 | { |
671 | int ret; | |
672 | ||
9fe7d6bf MS |
673 | if (debug_lin_lwp) |
674 | { | |
675 | fprintf_unfiltered (gdb_stdlog, | |
676 | "SC: kill %s **<SIGSTOP>**\n", | |
677 | target_pid_to_str (lp->ptid)); | |
678 | } | |
b757528f JJ |
679 | errno = 0; |
680 | ret = kill_lwp (GET_LWP (lp->ptid), SIGSTOP); | |
681 | if (debug_lin_lwp) | |
682 | { | |
683 | fprintf_unfiltered (gdb_stdlog, | |
684 | "SC: lwp kill %d %s\n", | |
685 | ret, | |
686 | errno ? safe_strerror (errno) : "ERRNO-OK"); | |
687 | } | |
fb0e1ba7 MK |
688 | |
689 | lp->signalled = 1; | |
690 | gdb_assert (lp->status == 0); | |
691 | } | |
692 | ||
693 | return 0; | |
694 | } | |
695 | ||
de4ca854 MK |
696 | /* Wait until LP is stopped. If DATA is non-null it is interpreted as |
697 | a pointer to a set of signals to be flushed immediately. */ | |
fb0e1ba7 MK |
698 | |
699 | static int | |
700 | stop_wait_callback (struct lwp_info *lp, void *data) | |
701 | { | |
de4ca854 MK |
702 | sigset_t *flush_mask = data; |
703 | ||
bfb39158 | 704 | if (!lp->stopped) |
fb0e1ba7 | 705 | { |
fb0e1ba7 MK |
706 | int status; |
707 | ||
c64bd0ce DJ |
708 | status = wait_lwp (lp); |
709 | if (status == 0) | |
710 | return 0; | |
fb0e1ba7 | 711 | |
de4ca854 MK |
712 | /* Ignore any signals in FLUSH_MASK. */ |
713 | if (flush_mask && sigismember (flush_mask, WSTOPSIG (status))) | |
714 | { | |
bfb39158 DJ |
715 | if (!lp->signalled) |
716 | { | |
717 | lp->stopped = 1; | |
718 | return 0; | |
719 | } | |
720 | ||
9fe7d6bf | 721 | errno = 0; |
de4ca854 | 722 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); |
9fe7d6bf MS |
723 | if (debug_lin_lwp) |
724 | fprintf_unfiltered (gdb_stdlog, | |
725 | "PTRACE_CONT %s, 0, 0 (%s)\n", | |
726 | target_pid_to_str (lp->ptid), | |
727 | errno ? safe_strerror (errno) : "OK"); | |
728 | ||
de4ca854 MK |
729 | return stop_wait_callback (lp, flush_mask); |
730 | } | |
731 | ||
fb0e1ba7 MK |
732 | if (WSTOPSIG (status) != SIGSTOP) |
733 | { | |
b1aeb4c5 | 734 | if (WSTOPSIG (status) == SIGTRAP) |
fb0e1ba7 MK |
735 | { |
736 | /* If a LWP other than the LWP that we're reporting an | |
6949171e JJ |
737 | event for has hit a GDB breakpoint (as opposed to |
738 | some random trap signal), then just arrange for it to | |
739 | hit it again later. We don't keep the SIGTRAP status | |
740 | and don't forward the SIGTRAP signal to the LWP. We | |
741 | will handle the current event, eventually we will | |
742 | resume all LWPs, and this one will get its breakpoint | |
743 | trap again. | |
744 | ||
745 | If we do not do this, then we run the risk that the | |
746 | user will delete or disable the breakpoint, but the | |
747 | thread will have already tripped on it. */ | |
7ca673cd | 748 | |
c4365b19 | 749 | /* Now resume this LWP and get the SIGSTOP event. */ |
9fe7d6bf | 750 | errno = 0; |
c4365b19 | 751 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); |
b1aeb4c5 MS |
752 | if (debug_lin_lwp) |
753 | { | |
6949171e | 754 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
755 | "PTRACE_CONT %s, 0, 0 (%s)\n", |
756 | target_pid_to_str (lp->ptid), | |
757 | errno ? safe_strerror (errno) : "OK"); | |
758 | ||
6949171e | 759 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
760 | "SWC: Candidate SIGTRAP event in %s\n", |
761 | target_pid_to_str (lp->ptid)); | |
b1aeb4c5 MS |
762 | } |
763 | /* Hold the SIGTRAP for handling by lin_lwp_wait. */ | |
764 | stop_wait_callback (lp, data); | |
765 | /* If there's another event, throw it back into the queue. */ | |
766 | if (lp->status) | |
9fe7d6bf | 767 | { |
b757528f JJ |
768 | if (debug_lin_lwp) |
769 | { | |
770 | fprintf_unfiltered (gdb_stdlog, | |
771 | "SWC: kill %s, %s\n", | |
772 | target_pid_to_str (lp->ptid), | |
773 | status_to_str ((int) status)); | |
774 | } | |
775 | kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (lp->status)); | |
9fe7d6bf | 776 | } |
b1aeb4c5 MS |
777 | /* Save the sigtrap event. */ |
778 | lp->status = status; | |
779 | return 0; | |
fb0e1ba7 MK |
780 | } |
781 | else | |
782 | { | |
b1aeb4c5 | 783 | /* The thread was stopped with a signal other than |
6949171e | 784 | SIGSTOP, and didn't accidentally trip a breakpoint. */ |
b1aeb4c5 | 785 | |
7ca673cd | 786 | if (debug_lin_lwp) |
b1aeb4c5 | 787 | { |
6949171e | 788 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf | 789 | "SWC: Pending event %s in %s\n", |
6949171e | 790 | status_to_str ((int) status), |
9fe7d6bf | 791 | target_pid_to_str (lp->ptid)); |
b1aeb4c5 MS |
792 | } |
793 | /* Now resume this LWP and get the SIGSTOP event. */ | |
9fe7d6bf | 794 | errno = 0; |
b1aeb4c5 | 795 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); |
9fe7d6bf | 796 | if (debug_lin_lwp) |
6949171e | 797 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
798 | "SWC: PTRACE_CONT %s, 0, 0 (%s)\n", |
799 | target_pid_to_str (lp->ptid), | |
800 | errno ? safe_strerror (errno) : "OK"); | |
7ca673cd | 801 | |
b1aeb4c5 | 802 | /* Hold this event/waitstatus while we check to see if |
6949171e | 803 | there are any more (we still want to get that SIGSTOP). */ |
b1aeb4c5 MS |
804 | stop_wait_callback (lp, data); |
805 | /* If the lp->status field is still empty, use it to hold | |
6949171e JJ |
806 | this event. If not, then this event must be returned |
807 | to the event queue of the LWP. */ | |
b1aeb4c5 MS |
808 | if (lp->status == 0) |
809 | lp->status = status; | |
810 | else | |
9fe7d6bf MS |
811 | { |
812 | if (debug_lin_lwp) | |
813 | { | |
6949171e | 814 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf | 815 | "SWC: kill %s, %s\n", |
6949171e | 816 | target_pid_to_str (lp->ptid), |
9fe7d6bf MS |
817 | status_to_str ((int) status)); |
818 | } | |
b757528f | 819 | kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (status)); |
9fe7d6bf | 820 | } |
b1aeb4c5 | 821 | return 0; |
fb0e1ba7 MK |
822 | } |
823 | } | |
824 | else | |
825 | { | |
826 | /* We caught the SIGSTOP that we intended to catch, so | |
6949171e | 827 | there's no SIGSTOP pending. */ |
b1aeb4c5 | 828 | lp->stopped = 1; |
fb0e1ba7 MK |
829 | lp->signalled = 0; |
830 | } | |
831 | } | |
832 | ||
833 | return 0; | |
834 | } | |
835 | ||
bfb39158 DJ |
836 | /* Check whether PID has any pending signals in FLUSH_MASK. If so set |
837 | the appropriate bits in PENDING, and return 1 - otherwise return 0. */ | |
838 | ||
839 | static int | |
840 | lin_lwp_has_pending (int pid, sigset_t *pending, sigset_t *flush_mask) | |
841 | { | |
842 | sigset_t blocked, ignored; | |
843 | int i; | |
844 | ||
845 | linux_proc_pending_signals (pid, pending, &blocked, &ignored); | |
846 | ||
847 | if (!flush_mask) | |
848 | return 0; | |
849 | ||
850 | for (i = 1; i < NSIG; i++) | |
851 | if (sigismember (pending, i)) | |
852 | if (!sigismember (flush_mask, i) | |
853 | || sigismember (&blocked, i) | |
854 | || sigismember (&ignored, i)) | |
855 | sigdelset (pending, i); | |
856 | ||
857 | if (sigisemptyset (pending)) | |
858 | return 0; | |
859 | ||
860 | return 1; | |
861 | } | |
862 | ||
863 | /* DATA is interpreted as a mask of signals to flush. If LP has | |
864 | signals pending, and they are all in the flush mask, then arrange | |
865 | to flush them. LP should be stopped, as should all other threads | |
866 | it might share a signal queue with. */ | |
867 | ||
868 | static int | |
869 | flush_callback (struct lwp_info *lp, void *data) | |
870 | { | |
871 | sigset_t *flush_mask = data; | |
872 | sigset_t pending, intersection, blocked, ignored; | |
873 | int pid, status; | |
874 | ||
875 | /* Normally, when an LWP exits, it is removed from the LWP list. The | |
876 | last LWP isn't removed till later, however. So if there is only | |
877 | one LWP on the list, make sure it's alive. */ | |
878 | if (lwp_list == lp && lp->next == NULL) | |
879 | if (!lin_lwp_thread_alive (lp->ptid)) | |
880 | return 0; | |
881 | ||
882 | /* Just because the LWP is stopped doesn't mean that new signals | |
883 | can't arrive from outside, so this function must be careful of | |
884 | race conditions. However, because all threads are stopped, we | |
885 | can assume that the pending mask will not shrink unless we resume | |
886 | the LWP, and that it will then get another signal. We can't | |
887 | control which one, however. */ | |
888 | ||
889 | if (lp->status) | |
890 | { | |
891 | if (debug_lin_lwp) | |
892 | printf_unfiltered ("FC: LP has pending status %06x\n", lp->status); | |
893 | if (WIFSTOPPED (lp->status) && sigismember (flush_mask, WSTOPSIG (lp->status))) | |
894 | lp->status = 0; | |
895 | } | |
896 | ||
897 | while (lin_lwp_has_pending (GET_LWP (lp->ptid), &pending, flush_mask)) | |
898 | { | |
899 | int ret; | |
900 | ||
901 | errno = 0; | |
902 | ret = ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
903 | if (debug_lin_lwp) | |
904 | fprintf_unfiltered (gdb_stderr, | |
905 | "FC: Sent PTRACE_CONT, ret %d %d\n", ret, errno); | |
906 | ||
907 | lp->stopped = 0; | |
908 | stop_wait_callback (lp, flush_mask); | |
909 | if (debug_lin_lwp) | |
910 | fprintf_unfiltered (gdb_stderr, | |
911 | "FC: Wait finished; saved status is %d\n", | |
912 | lp->status); | |
913 | } | |
914 | ||
915 | return 0; | |
916 | } | |
917 | ||
fb0e1ba7 MK |
918 | /* Return non-zero if LP has a wait status pending. */ |
919 | ||
920 | static int | |
921 | status_callback (struct lwp_info *lp, void *data) | |
922 | { | |
fce0e6e1 MK |
923 | /* Only report a pending wait status if we pretend that this has |
924 | indeed been resumed. */ | |
925 | return (lp->status != 0 && lp->resumed); | |
fb0e1ba7 MK |
926 | } |
927 | ||
928 | /* Return non-zero if LP isn't stopped. */ | |
929 | ||
930 | static int | |
931 | running_callback (struct lwp_info *lp, void *data) | |
932 | { | |
550950b8 | 933 | return (lp->stopped == 0 || (lp->status != 0 && lp->resumed)); |
fb0e1ba7 MK |
934 | } |
935 | ||
00d4fce6 | 936 | /* Count the LWP's that have had events. */ |
b1aeb4c5 MS |
937 | |
938 | static int | |
939 | count_events_callback (struct lwp_info *lp, void *data) | |
940 | { | |
941 | int *count = data; | |
942 | ||
00d4fce6 MK |
943 | gdb_assert (count != NULL); |
944 | ||
945 | /* Count only LWPs that have a SIGTRAP event pending. */ | |
946 | if (lp->status != 0 | |
947 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) | |
b1aeb4c5 MS |
948 | (*count)++; |
949 | ||
950 | return 0; | |
951 | } | |
952 | ||
00d4fce6 | 953 | /* Select the LWP (if any) that is currently being single-stepped. */ |
b1aeb4c5 MS |
954 | |
955 | static int | |
956 | select_singlestep_lwp_callback (struct lwp_info *lp, void *data) | |
957 | { | |
958 | if (lp->step && lp->status != 0) | |
959 | return 1; | |
960 | else | |
961 | return 0; | |
962 | } | |
963 | ||
00d4fce6 | 964 | /* Select the Nth LWP that has had a SIGTRAP event. */ |
b1aeb4c5 MS |
965 | |
966 | static int | |
967 | select_event_lwp_callback (struct lwp_info *lp, void *data) | |
968 | { | |
969 | int *selector = data; | |
970 | ||
00d4fce6 MK |
971 | gdb_assert (selector != NULL); |
972 | ||
973 | /* Select only LWPs that have a SIGTRAP event pending. */ | |
974 | if (lp->status != 0 | |
975 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) | |
b1aeb4c5 MS |
976 | if ((*selector)-- == 0) |
977 | return 1; | |
978 | ||
979 | return 0; | |
980 | } | |
981 | ||
982 | static int | |
983 | cancel_breakpoints_callback (struct lwp_info *lp, void *data) | |
984 | { | |
985 | struct lwp_info *event_lp = data; | |
986 | ||
00d4fce6 MK |
987 | /* Leave the LWP that has been elected to receive a SIGTRAP alone. */ |
988 | if (lp == event_lp) | |
989 | return 0; | |
990 | ||
991 | /* If a LWP other than the LWP that we're reporting an event for has | |
992 | hit a GDB breakpoint (as opposed to some random trap signal), | |
993 | then just arrange for it to hit it again later. We don't keep | |
994 | the SIGTRAP status and don't forward the SIGTRAP signal to the | |
995 | LWP. We will handle the current event, eventually we will resume | |
996 | all LWPs, and this one will get its breakpoint trap again. | |
997 | ||
998 | If we do not do this, then we run the risk that the user will | |
999 | delete or disable the breakpoint, but the LWP will have already | |
1000 | tripped on it. */ | |
1001 | ||
1002 | if (lp->status != 0 | |
6949171e JJ |
1003 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP |
1004 | && breakpoint_inserted_here_p (read_pc_pid (lp->ptid) - | |
00d4fce6 | 1005 | DECR_PC_AFTER_BREAK)) |
b1aeb4c5 MS |
1006 | { |
1007 | if (debug_lin_lwp) | |
00d4fce6 | 1008 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
1009 | "CBC: Push back breakpoint for %s\n", |
1010 | target_pid_to_str (lp->ptid)); | |
00d4fce6 MK |
1011 | |
1012 | /* Back up the PC if necessary. */ | |
b1aeb4c5 | 1013 | if (DECR_PC_AFTER_BREAK) |
00d4fce6 MK |
1014 | write_pc_pid (read_pc_pid (lp->ptid) - DECR_PC_AFTER_BREAK, lp->ptid); |
1015 | ||
1016 | /* Throw away the SIGTRAP. */ | |
b1aeb4c5 MS |
1017 | lp->status = 0; |
1018 | } | |
00d4fce6 | 1019 | |
b1aeb4c5 MS |
1020 | return 0; |
1021 | } | |
1022 | ||
00d4fce6 | 1023 | /* Select one LWP out of those that have events pending. */ |
b1aeb4c5 MS |
1024 | |
1025 | static void | |
1026 | select_event_lwp (struct lwp_info **orig_lp, int *status) | |
1027 | { | |
1028 | int num_events = 0; | |
1029 | int random_selector; | |
1030 | struct lwp_info *event_lp; | |
1031 | ||
00d4fce6 MK |
1032 | /* Record the wait status for the origional LWP. */ |
1033 | (*orig_lp)->status = *status; | |
1034 | ||
1035 | /* Give preference to any LWP that is being single-stepped. */ | |
b1aeb4c5 MS |
1036 | event_lp = iterate_over_lwps (select_singlestep_lwp_callback, NULL); |
1037 | if (event_lp != NULL) | |
1038 | { | |
1039 | if (debug_lin_lwp) | |
00d4fce6 | 1040 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
1041 | "SEL: Select single-step %s\n", |
1042 | target_pid_to_str (event_lp->ptid)); | |
b1aeb4c5 MS |
1043 | } |
1044 | else | |
1045 | { | |
1046 | /* No single-stepping LWP. Select one at random, out of those | |
6949171e | 1047 | which have had SIGTRAP events. */ |
b1aeb4c5 | 1048 | |
00d4fce6 MK |
1049 | /* First see how many SIGTRAP events we have. */ |
1050 | iterate_over_lwps (count_events_callback, &num_events); | |
b1aeb4c5 | 1051 | |
00d4fce6 MK |
1052 | /* Now randomly pick a LWP out of those that have had a SIGTRAP. */ |
1053 | random_selector = (int) | |
b1aeb4c5 MS |
1054 | ((num_events * (double) rand ()) / (RAND_MAX + 1.0)); |
1055 | ||
00d4fce6 | 1056 | if (debug_lin_lwp && num_events > 1) |
6949171e JJ |
1057 | fprintf_unfiltered (gdb_stdlog, |
1058 | "SEL: Found %d SIGTRAP events, selecting #%d\n", | |
00d4fce6 | 1059 | num_events, random_selector); |
b1aeb4c5 | 1060 | |
00d4fce6 MK |
1061 | event_lp = iterate_over_lwps (select_event_lwp_callback, |
1062 | &random_selector); | |
b1aeb4c5 MS |
1063 | } |
1064 | ||
1065 | if (event_lp != NULL) | |
1066 | { | |
00d4fce6 | 1067 | /* Switch the event LWP. */ |
b1aeb4c5 | 1068 | *orig_lp = event_lp; |
6949171e | 1069 | *status = event_lp->status; |
b1aeb4c5 | 1070 | } |
00d4fce6 MK |
1071 | |
1072 | /* Flush the wait status for the event LWP. */ | |
1073 | (*orig_lp)->status = 0; | |
b1aeb4c5 MS |
1074 | } |
1075 | ||
fce0e6e1 MK |
1076 | /* Return non-zero if LP has been resumed. */ |
1077 | ||
1078 | static int | |
1079 | resumed_callback (struct lwp_info *lp, void *data) | |
1080 | { | |
1081 | return lp->resumed; | |
1082 | } | |
1083 | ||
cacab7c4 MK |
1084 | #ifdef CHILD_WAIT |
1085 | ||
1086 | /* We need to override child_wait to support attaching to cloned | |
1087 | processes, since a normal wait (as done by the default version) | |
1088 | ignores those processes. */ | |
1089 | ||
1090 | /* Wait for child PTID to do something. Return id of the child, | |
1091 | minus_one_ptid in case of error; store status into *OURSTATUS. */ | |
1092 | ||
1093 | ptid_t | |
1094 | child_wait (ptid_t ptid, struct target_waitstatus *ourstatus) | |
1095 | { | |
1096 | int save_errno; | |
1097 | int status; | |
1098 | pid_t pid; | |
1099 | ||
1100 | do | |
1101 | { | |
1102 | set_sigint_trap (); /* Causes SIGINT to be passed on to the | |
1103 | attached process. */ | |
1104 | set_sigio_trap (); | |
1105 | ||
1106 | pid = waitpid (GET_PID (ptid), &status, 0); | |
1107 | if (pid == -1 && errno == ECHILD) | |
1108 | /* Try again with __WCLONE to check cloned processes. */ | |
1109 | pid = waitpid (GET_PID (ptid), &status, __WCLONE); | |
9fe7d6bf MS |
1110 | |
1111 | if (debug_lin_lwp) | |
1112 | { | |
6949171e | 1113 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf | 1114 | "CW: waitpid %ld received %s\n", |
6949171e | 1115 | (long) pid, status_to_str (status)); |
9fe7d6bf MS |
1116 | } |
1117 | ||
cacab7c4 MK |
1118 | save_errno = errno; |
1119 | ||
b3ba1b44 | 1120 | /* Make sure we don't report an event for the exit of the |
6949171e JJ |
1121 | original program, if we've detached from it. */ |
1122 | if (pid != -1 && !WIFSTOPPED (status) && pid != GET_PID (inferior_ptid)) | |
b3ba1b44 DJ |
1123 | { |
1124 | pid = -1; | |
1125 | save_errno = EINTR; | |
1126 | } | |
1127 | ||
ae087d01 DJ |
1128 | /* Check for stop events reported by a process we didn't already |
1129 | know about - in this case, anything other than inferior_ptid. | |
1130 | ||
1131 | If we're expecting to receive stopped processes after fork, | |
1132 | vfork, and clone events, then we'll just add the new one to | |
1133 | our list and go back to waiting for the event to be reported | |
1134 | - the stopped process might be returned from waitpid before | |
1135 | or after the event is. If we want to handle debugging of | |
1136 | CLONE_PTRACE processes we need to do more here, i.e. switch | |
1137 | to multi-threaded mode. */ | |
1138 | if (pid != -1 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP | |
1139 | && pid != GET_PID (inferior_ptid)) | |
1140 | { | |
c538c11c | 1141 | linux_record_stopped_pid (pid); |
ae087d01 DJ |
1142 | pid = -1; |
1143 | save_errno = EINTR; | |
1144 | } | |
1145 | ||
cacab7c4 MK |
1146 | clear_sigio_trap (); |
1147 | clear_sigint_trap (); | |
1148 | } | |
2d1bfe2e | 1149 | while (pid == -1 && save_errno == EINTR); |
cacab7c4 MK |
1150 | |
1151 | if (pid == -1) | |
1152 | { | |
6949171e | 1153 | warning ("Child process unexpectedly missing: %s", |
9fe7d6bf | 1154 | safe_strerror (errno)); |
cacab7c4 MK |
1155 | |
1156 | /* Claim it exited with unknown signal. */ | |
1157 | ourstatus->kind = TARGET_WAITKIND_SIGNALLED; | |
1158 | ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN; | |
1159 | return minus_one_ptid; | |
1160 | } | |
1161 | ||
4de4c07c DJ |
1162 | /* Handle GNU/Linux's extended waitstatus for trace events. */ |
1163 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0) | |
1164 | return linux_handle_extended_wait (pid, status, ourstatus); | |
1165 | ||
cacab7c4 MK |
1166 | store_waitstatus (ourstatus, status); |
1167 | return pid_to_ptid (pid); | |
1168 | } | |
1169 | ||
1170 | #endif | |
1171 | ||
b757528f JJ |
1172 | /* Stop an active thread, verify it still exists, then resume it. */ |
1173 | ||
1174 | static int | |
1175 | stop_and_resume_callback (struct lwp_info *lp, void *data) | |
1176 | { | |
1177 | struct lwp_info *ptr; | |
1178 | ||
1179 | if (!lp->stopped && !lp->signalled) | |
1180 | { | |
1181 | stop_callback (lp, NULL); | |
1182 | stop_wait_callback (lp, NULL); | |
1183 | /* Resume if the lwp still exists. */ | |
1184 | for (ptr = lwp_list; ptr; ptr = ptr->next) | |
1185 | if (lp == ptr) | |
550950b8 JJ |
1186 | { |
1187 | resume_callback (lp, NULL); | |
1188 | resume_set_callback (lp, NULL); | |
1189 | } | |
b757528f JJ |
1190 | } |
1191 | return 0; | |
1192 | } | |
1193 | ||
39f77062 KB |
1194 | static ptid_t |
1195 | lin_lwp_wait (ptid_t ptid, struct target_waitstatus *ourstatus) | |
fb0e1ba7 MK |
1196 | { |
1197 | struct lwp_info *lp = NULL; | |
1198 | int options = 0; | |
1199 | int status = 0; | |
39f77062 | 1200 | pid_t pid = PIDGET (ptid); |
de4ca854 MK |
1201 | sigset_t flush_mask; |
1202 | ||
1203 | sigemptyset (&flush_mask); | |
fb0e1ba7 | 1204 | |
3f07c44b | 1205 | /* Make sure SIGCHLD is blocked. */ |
6949171e | 1206 | if (!sigismember (&blocked_mask, SIGCHLD)) |
3f07c44b MK |
1207 | { |
1208 | sigaddset (&blocked_mask, SIGCHLD); | |
1209 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
1210 | } | |
1211 | ||
6949171e | 1212 | retry: |
fb0e1ba7 | 1213 | |
9a973a8f MK |
1214 | /* Make sure there is at least one LWP that has been resumed, at |
1215 | least if there are any LWPs at all. */ | |
1216 | gdb_assert (num_lwps == 0 || iterate_over_lwps (resumed_callback, NULL)); | |
fce0e6e1 | 1217 | |
fb0e1ba7 MK |
1218 | /* First check if there is a LWP with a wait status pending. */ |
1219 | if (pid == -1) | |
1220 | { | |
b1aeb4c5 | 1221 | /* Any LWP that's been resumed will do. */ |
fb0e1ba7 MK |
1222 | lp = iterate_over_lwps (status_callback, NULL); |
1223 | if (lp) | |
1224 | { | |
fb0e1ba7 MK |
1225 | status = lp->status; |
1226 | lp->status = 0; | |
b1aeb4c5 MS |
1227 | |
1228 | if (debug_lin_lwp && status) | |
58eeadba | 1229 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf | 1230 | "LLW: Using pending wait status %s for %s.\n", |
6949171e | 1231 | status_to_str (status), |
9fe7d6bf | 1232 | target_pid_to_str (lp->ptid)); |
fb0e1ba7 MK |
1233 | } |
1234 | ||
1235 | /* But if we don't fine one, we'll have to wait, and check both | |
1236 | cloned and uncloned processes. We start with the cloned | |
1237 | processes. */ | |
1238 | options = __WCLONE | WNOHANG; | |
1239 | } | |
39f77062 | 1240 | else if (is_lwp (ptid)) |
fb0e1ba7 | 1241 | { |
7ca673cd | 1242 | if (debug_lin_lwp) |
6949171e | 1243 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
1244 | "LLW: Waiting for specific LWP %s.\n", |
1245 | target_pid_to_str (ptid)); | |
7ca673cd | 1246 | |
fb0e1ba7 | 1247 | /* We have a specific LWP to check. */ |
39f77062 | 1248 | lp = find_lwp_pid (ptid); |
fb0e1ba7 MK |
1249 | gdb_assert (lp); |
1250 | status = lp->status; | |
1251 | lp->status = 0; | |
7ca673cd | 1252 | |
b1aeb4c5 | 1253 | if (debug_lin_lwp && status) |
58eeadba | 1254 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf | 1255 | "LLW: Using pending wait status %s for %s.\n", |
6949171e | 1256 | status_to_str (status), |
9fe7d6bf | 1257 | target_pid_to_str (lp->ptid)); |
fb0e1ba7 MK |
1258 | |
1259 | /* If we have to wait, take into account whether PID is a cloned | |
1260 | process or not. And we have to convert it to something that | |
1261 | the layer beneath us can understand. */ | |
cacab7c4 | 1262 | options = lp->cloned ? __WCLONE : 0; |
39f77062 | 1263 | pid = GET_LWP (ptid); |
fb0e1ba7 MK |
1264 | } |
1265 | ||
1266 | if (status && lp->signalled) | |
1267 | { | |
1268 | /* A pending SIGSTOP may interfere with the normal stream of | |
6949171e JJ |
1269 | events. In a typical case where interference is a problem, |
1270 | we have a SIGSTOP signal pending for LWP A while | |
1271 | single-stepping it, encounter an event in LWP B, and take the | |
1272 | pending SIGSTOP while trying to stop LWP A. After processing | |
1273 | the event in LWP B, LWP A is continued, and we'll never see | |
1274 | the SIGTRAP associated with the last time we were | |
1275 | single-stepping LWP A. */ | |
fb0e1ba7 MK |
1276 | |
1277 | /* Resume the thread. It should halt immediately returning the | |
6949171e | 1278 | pending SIGSTOP. */ |
9fe7d6bf | 1279 | registers_changed (); |
39f77062 | 1280 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, |
6949171e | 1281 | TARGET_SIGNAL_0); |
9fe7d6bf MS |
1282 | if (debug_lin_lwp) |
1283 | fprintf_unfiltered (gdb_stdlog, | |
1284 | "LLW: %s %s, 0, 0 (expect SIGSTOP)\n", | |
1285 | lp->step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT", | |
1286 | target_pid_to_str (lp->ptid)); | |
fb0e1ba7 | 1287 | lp->stopped = 0; |
fce0e6e1 | 1288 | gdb_assert (lp->resumed); |
fb0e1ba7 MK |
1289 | |
1290 | /* This should catch the pending SIGSTOP. */ | |
1291 | stop_wait_callback (lp, NULL); | |
1292 | } | |
1293 | ||
6949171e JJ |
1294 | set_sigint_trap (); /* Causes SIGINT to be passed on to the |
1295 | attached process. */ | |
fb0e1ba7 MK |
1296 | set_sigio_trap (); |
1297 | ||
1298 | while (status == 0) | |
1299 | { | |
1300 | pid_t lwpid; | |
1301 | ||
1302 | lwpid = waitpid (pid, &status, options); | |
1303 | if (lwpid > 0) | |
1304 | { | |
1305 | gdb_assert (pid == -1 || lwpid == pid); | |
1306 | ||
9fe7d6bf MS |
1307 | if (debug_lin_lwp) |
1308 | { | |
1309 | fprintf_unfiltered (gdb_stdlog, | |
1310 | "LLW: waitpid %ld received %s\n", | |
6949171e | 1311 | (long) lwpid, status_to_str (status)); |
9fe7d6bf MS |
1312 | } |
1313 | ||
39f77062 | 1314 | lp = find_lwp_pid (pid_to_ptid (lwpid)); |
b3ba1b44 | 1315 | |
ae087d01 DJ |
1316 | /* Check for stop events reported by a process we didn't |
1317 | already know about - anything not already in our LWP | |
1318 | list. | |
1319 | ||
1320 | If we're expecting to receive stopped processes after | |
1321 | fork, vfork, and clone events, then we'll just add the | |
1322 | new one to our list and go back to waiting for the event | |
1323 | to be reported - the stopped process might be returned | |
1324 | from waitpid before or after the event is. */ | |
1325 | if (WIFSTOPPED (status) && !lp) | |
1326 | { | |
1327 | linux_record_stopped_pid (lwpid); | |
1328 | status = 0; | |
1329 | continue; | |
1330 | } | |
1331 | ||
b3ba1b44 DJ |
1332 | /* Make sure we don't report an event for the exit of an LWP not in |
1333 | our list, i.e. not part of the current process. This can happen | |
1334 | if we detach from a program we original forked and then it | |
1335 | exits. */ | |
6949171e | 1336 | if (!WIFSTOPPED (status) && !lp) |
b3ba1b44 DJ |
1337 | { |
1338 | status = 0; | |
1339 | continue; | |
1340 | } | |
1341 | ||
ae087d01 DJ |
1342 | /* NOTE drow/2003-06-17: This code seems to be meant for debugging |
1343 | CLONE_PTRACE processes which do not use the thread library - | |
1344 | otherwise we wouldn't find the new LWP this way. That doesn't | |
1345 | currently work, and the following code is currently unreachable | |
1346 | due to the two blocks above. If it's fixed some day, this code | |
1347 | should be broken out into a function so that we can also pick up | |
1348 | LWPs from the new interface. */ | |
6949171e | 1349 | if (!lp) |
fb0e1ba7 | 1350 | { |
39f77062 | 1351 | lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid))); |
cacab7c4 MK |
1352 | if (options & __WCLONE) |
1353 | lp->cloned = 1; | |
1354 | ||
fb0e1ba7 MK |
1355 | if (threaded) |
1356 | { | |
3f07c44b MK |
1357 | gdb_assert (WIFSTOPPED (status) |
1358 | && WSTOPSIG (status) == SIGSTOP); | |
fb0e1ba7 MK |
1359 | lp->signalled = 1; |
1360 | ||
6949171e | 1361 | if (!in_thread_list (inferior_ptid)) |
fb0e1ba7 | 1362 | { |
39f77062 | 1363 | inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid), |
6949171e | 1364 | GET_PID (inferior_ptid)); |
39f77062 | 1365 | add_thread (inferior_ptid); |
fb0e1ba7 MK |
1366 | } |
1367 | ||
39f77062 | 1368 | add_thread (lp->ptid); |
fb0e1ba7 | 1369 | printf_unfiltered ("[New %s]\n", |
39f77062 | 1370 | target_pid_to_str (lp->ptid)); |
fb0e1ba7 MK |
1371 | } |
1372 | } | |
1373 | ||
b757528f | 1374 | /* Check if the thread has exited. */ |
fb0e1ba7 | 1375 | if ((WIFEXITED (status) || WIFSIGNALED (status)) && num_lwps > 1) |
b757528f JJ |
1376 | { |
1377 | if (in_thread_list (lp->ptid)) | |
1378 | { | |
1379 | /* Core GDB cannot deal with us deleting the current | |
1380 | thread. */ | |
1381 | if (!ptid_equal (lp->ptid, inferior_ptid)) | |
1382 | delete_thread (lp->ptid); | |
1383 | printf_unfiltered ("[%s exited]\n", | |
1384 | target_pid_to_str (lp->ptid)); | |
1385 | } | |
1386 | ||
1387 | /* If this is the main thread, we must stop all threads and | |
1388 | verify if they are still alive. This is because in the nptl | |
1389 | thread model, there is no signal issued for exiting LWPs | |
1390 | other than the main thread. We only get the main thread | |
1391 | exit signal once all child threads have already exited. | |
1392 | If we stop all the threads and use the stop_wait_callback | |
1393 | to check if they have exited we can determine whether this | |
1394 | signal should be ignored or whether it means the end of the | |
1395 | debugged application, regardless of which threading model | |
1396 | is being used. */ | |
1397 | if (GET_PID (lp->ptid) == GET_LWP (lp->ptid)) | |
1398 | { | |
1399 | lp->stopped = 1; | |
1400 | iterate_over_lwps (stop_and_resume_callback, NULL); | |
1401 | } | |
1402 | ||
1403 | if (debug_lin_lwp) | |
1404 | fprintf_unfiltered (gdb_stdlog, | |
1405 | "LLW: %s exited.\n", | |
1406 | target_pid_to_str (lp->ptid)); | |
1407 | ||
1408 | delete_lwp (lp->ptid); | |
1409 | ||
1410 | /* If there is at least one more LWP, then the exit signal | |
1411 | was not the end of the debugged application and should be | |
1412 | ignored. */ | |
1413 | if (num_lwps > 0) | |
1414 | { | |
1415 | /* Make sure there is at least one thread running. */ | |
1416 | gdb_assert (iterate_over_lwps (running_callback, NULL)); | |
1417 | ||
1418 | /* Discard the event. */ | |
1419 | status = 0; | |
1420 | continue; | |
1421 | } | |
1422 | } | |
1423 | ||
1424 | /* Check if the current LWP has previously exited. In the nptl | |
1425 | thread model, LWPs other than the main thread do not issue | |
1426 | signals when they exit so we must check whenever the thread | |
1427 | has stopped. A similar check is made in stop_wait_callback(). */ | |
1428 | if (num_lwps > 1 && !lin_lwp_thread_alive (lp->ptid)) | |
fb0e1ba7 | 1429 | { |
39f77062 | 1430 | if (in_thread_list (lp->ptid)) |
fb0e1ba7 | 1431 | { |
e6328671 | 1432 | /* Core GDB cannot deal with us deleting the current |
6949171e JJ |
1433 | thread. */ |
1434 | if (!ptid_equal (lp->ptid, inferior_ptid)) | |
39f77062 | 1435 | delete_thread (lp->ptid); |
fb0e1ba7 | 1436 | printf_unfiltered ("[%s exited]\n", |
39f77062 | 1437 | target_pid_to_str (lp->ptid)); |
fb0e1ba7 | 1438 | } |
7ca673cd | 1439 | if (debug_lin_lwp) |
6949171e JJ |
1440 | fprintf_unfiltered (gdb_stdlog, |
1441 | "LLW: %s exited.\n", | |
39f77062 | 1442 | target_pid_to_str (lp->ptid)); |
7ca673cd | 1443 | |
39f77062 | 1444 | delete_lwp (lp->ptid); |
fb0e1ba7 MK |
1445 | |
1446 | /* Make sure there is at least one thread running. */ | |
1447 | gdb_assert (iterate_over_lwps (running_callback, NULL)); | |
1448 | ||
1449 | /* Discard the event. */ | |
1450 | status = 0; | |
1451 | continue; | |
1452 | } | |
1453 | ||
1454 | /* Make sure we don't report a SIGSTOP that we sent | |
6949171e | 1455 | ourselves in an attempt to stop an LWP. */ |
9fe7d6bf | 1456 | if (lp->signalled |
6949171e | 1457 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP) |
fb0e1ba7 | 1458 | { |
7ca673cd | 1459 | if (debug_lin_lwp) |
6949171e | 1460 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf | 1461 | "LLW: Delayed SIGSTOP caught for %s.\n", |
39f77062 | 1462 | target_pid_to_str (lp->ptid)); |
7ca673cd | 1463 | |
fb0e1ba7 MK |
1464 | /* This is a delayed SIGSTOP. */ |
1465 | lp->signalled = 0; | |
1466 | ||
9fe7d6bf | 1467 | registers_changed (); |
39f77062 | 1468 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, |
6949171e | 1469 | TARGET_SIGNAL_0); |
9fe7d6bf MS |
1470 | if (debug_lin_lwp) |
1471 | fprintf_unfiltered (gdb_stdlog, | |
1472 | "LLW: %s %s, 0, 0 (discard SIGSTOP)\n", | |
6949171e | 1473 | lp->step ? |
9fe7d6bf MS |
1474 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
1475 | target_pid_to_str (lp->ptid)); | |
1476 | ||
fb0e1ba7 | 1477 | lp->stopped = 0; |
fce0e6e1 | 1478 | gdb_assert (lp->resumed); |
fb0e1ba7 MK |
1479 | |
1480 | /* Discard the event. */ | |
1481 | status = 0; | |
1482 | continue; | |
1483 | } | |
1484 | ||
1485 | break; | |
1486 | } | |
1487 | ||
1488 | if (pid == -1) | |
1489 | { | |
1490 | /* Alternate between checking cloned and uncloned processes. */ | |
1491 | options ^= __WCLONE; | |
1492 | ||
1493 | /* And suspend every time we have checked both. */ | |
1494 | if (options & __WCLONE) | |
1495 | sigsuspend (&suspend_mask); | |
1496 | } | |
1497 | ||
1498 | /* We shouldn't end up here unless we want to try again. */ | |
1499 | gdb_assert (status == 0); | |
1500 | } | |
1501 | ||
1502 | clear_sigio_trap (); | |
1503 | clear_sigint_trap (); | |
1504 | ||
1505 | gdb_assert (lp); | |
1506 | ||
1507 | /* Don't report signals that GDB isn't interested in, such as | |
1508 | signals that are neither printed nor stopped upon. Stopping all | |
1509 | threads can be a bit time-consuming so if we want decent | |
1510 | performance with heavily multi-threaded programs, especially when | |
1511 | they're using a high frequency timer, we'd better avoid it if we | |
1512 | can. */ | |
1513 | ||
1514 | if (WIFSTOPPED (status)) | |
1515 | { | |
1516 | int signo = target_signal_from_host (WSTOPSIG (status)); | |
1517 | ||
1518 | if (signal_stop_state (signo) == 0 | |
1519 | && signal_print_state (signo) == 0 | |
1520 | && signal_pass_state (signo) == 1) | |
1521 | { | |
fce0e6e1 | 1522 | /* FIMXE: kettenis/2001-06-06: Should we resume all threads |
6949171e JJ |
1523 | here? It is not clear we should. GDB may not expect |
1524 | other threads to run. On the other hand, not resuming | |
1525 | newly attached threads may cause an unwanted delay in | |
1526 | getting them running. */ | |
9fe7d6bf | 1527 | registers_changed (); |
c4365b19 | 1528 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, signo); |
9fe7d6bf MS |
1529 | if (debug_lin_lwp) |
1530 | fprintf_unfiltered (gdb_stdlog, | |
1531 | "LLW: %s %s, %s (preempt 'handle')\n", | |
6949171e JJ |
1532 | lp->step ? |
1533 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", | |
9fe7d6bf MS |
1534 | target_pid_to_str (lp->ptid), |
1535 | signo ? strsignal (signo) : "0"); | |
fce0e6e1 | 1536 | lp->stopped = 0; |
fb0e1ba7 MK |
1537 | status = 0; |
1538 | goto retry; | |
1539 | } | |
de4ca854 | 1540 | |
6949171e | 1541 | if (signo == TARGET_SIGNAL_INT && signal_pass_state (signo) == 0) |
de4ca854 MK |
1542 | { |
1543 | /* If ^C/BREAK is typed at the tty/console, SIGINT gets | |
6949171e JJ |
1544 | forwarded to the entire process group, that is, all LWP's |
1545 | will receive it. Since we only want to report it once, | |
1546 | we try to flush it from all LWPs except this one. */ | |
de4ca854 MK |
1547 | sigaddset (&flush_mask, SIGINT); |
1548 | } | |
fb0e1ba7 MK |
1549 | } |
1550 | ||
1551 | /* This LWP is stopped now. */ | |
1552 | lp->stopped = 1; | |
1553 | ||
b1aeb4c5 | 1554 | if (debug_lin_lwp) |
9fe7d6bf | 1555 | fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n", |
6949171e | 1556 | status_to_str (status), target_pid_to_str (lp->ptid)); |
b1aeb4c5 | 1557 | |
fb0e1ba7 MK |
1558 | /* Now stop all other LWP's ... */ |
1559 | iterate_over_lwps (stop_callback, NULL); | |
1560 | ||
1561 | /* ... and wait until all of them have reported back that they're no | |
1562 | longer running. */ | |
de4ca854 | 1563 | iterate_over_lwps (stop_wait_callback, &flush_mask); |
bfb39158 | 1564 | iterate_over_lwps (flush_callback, &flush_mask); |
fb0e1ba7 | 1565 | |
00d4fce6 MK |
1566 | /* If we're not waiting for a specific LWP, choose an event LWP from |
1567 | among those that have had events. Giving equal priority to all | |
1568 | LWPs that have had events helps prevent starvation. */ | |
1569 | if (pid == -1) | |
1570 | select_event_lwp (&lp, &status); | |
b1aeb4c5 | 1571 | |
00d4fce6 MK |
1572 | /* Now that we've selected our final event LWP, cancel any |
1573 | breakpoints in other LWPs that have hit a GDB breakpoint. See | |
1574 | the comment in cancel_breakpoints_callback to find out why. */ | |
1575 | iterate_over_lwps (cancel_breakpoints_callback, lp); | |
b1aeb4c5 | 1576 | |
fb0e1ba7 MK |
1577 | /* If we're not running in "threaded" mode, we'll report the bare |
1578 | process id. */ | |
1579 | ||
1580 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP) | |
b1aeb4c5 MS |
1581 | { |
1582 | trap_ptid = (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid))); | |
1583 | if (debug_lin_lwp) | |
6949171e | 1584 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
1585 | "LLW: trap_ptid is %s.\n", |
1586 | target_pid_to_str (trap_ptid)); | |
b1aeb4c5 | 1587 | } |
fb0e1ba7 | 1588 | else |
39f77062 | 1589 | trap_ptid = null_ptid; |
fb0e1ba7 | 1590 | |
4de4c07c DJ |
1591 | /* Handle GNU/Linux's extended waitstatus for trace events. */ |
1592 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0) | |
1593 | { | |
1594 | linux_handle_extended_wait (ptid_get_pid (trap_ptid), | |
1595 | status, ourstatus); | |
1596 | return trap_ptid; | |
1597 | } | |
1598 | ||
fb0e1ba7 | 1599 | store_waitstatus (ourstatus, status); |
39f77062 | 1600 | return (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid))); |
fb0e1ba7 MK |
1601 | } |
1602 | ||
1603 | static int | |
1604 | kill_callback (struct lwp_info *lp, void *data) | |
1605 | { | |
9fe7d6bf | 1606 | errno = 0; |
39f77062 | 1607 | ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0); |
9fe7d6bf | 1608 | if (debug_lin_lwp) |
6949171e | 1609 | fprintf_unfiltered (gdb_stdlog, |
9fe7d6bf MS |
1610 | "KC: PTRACE_KILL %s, 0, 0 (%s)\n", |
1611 | target_pid_to_str (lp->ptid), | |
1612 | errno ? safe_strerror (errno) : "OK"); | |
1613 | ||
fb0e1ba7 MK |
1614 | return 0; |
1615 | } | |
1616 | ||
1617 | static int | |
1618 | kill_wait_callback (struct lwp_info *lp, void *data) | |
1619 | { | |
1620 | pid_t pid; | |
1621 | ||
1622 | /* We must make sure that there are no pending events (delayed | |
1623 | SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current | |
1624 | program doesn't interfere with any following debugging session. */ | |
1625 | ||
1626 | /* For cloned processes we must check both with __WCLONE and | |
1627 | without, since the exit status of a cloned process isn't reported | |
1628 | with __WCLONE. */ | |
cacab7c4 | 1629 | if (lp->cloned) |
fb0e1ba7 MK |
1630 | { |
1631 | do | |
1632 | { | |
39f77062 | 1633 | pid = waitpid (GET_LWP (lp->ptid), NULL, __WCLONE); |
9fe7d6bf MS |
1634 | if (pid != (pid_t) -1 && debug_lin_lwp) |
1635 | { | |
1636 | fprintf_unfiltered (gdb_stdlog, | |
1637 | "KWC: wait %s received unknown.\n", | |
1638 | target_pid_to_str (lp->ptid)); | |
1639 | } | |
fb0e1ba7 | 1640 | } |
39f77062 | 1641 | while (pid == GET_LWP (lp->ptid)); |
fb0e1ba7 MK |
1642 | |
1643 | gdb_assert (pid == -1 && errno == ECHILD); | |
1644 | } | |
1645 | ||
1646 | do | |
1647 | { | |
39f77062 | 1648 | pid = waitpid (GET_LWP (lp->ptid), NULL, 0); |
9fe7d6bf MS |
1649 | if (pid != (pid_t) -1 && debug_lin_lwp) |
1650 | { | |
1651 | fprintf_unfiltered (gdb_stdlog, | |
6949171e | 1652 | "KWC: wait %s received unk.\n", |
9fe7d6bf MS |
1653 | target_pid_to_str (lp->ptid)); |
1654 | } | |
fb0e1ba7 | 1655 | } |
39f77062 | 1656 | while (pid == GET_LWP (lp->ptid)); |
fb0e1ba7 MK |
1657 | |
1658 | gdb_assert (pid == -1 && errno == ECHILD); | |
1659 | return 0; | |
1660 | } | |
1661 | ||
1662 | static void | |
1663 | lin_lwp_kill (void) | |
1664 | { | |
1665 | /* Kill all LWP's ... */ | |
1666 | iterate_over_lwps (kill_callback, NULL); | |
1667 | ||
1668 | /* ... and wait until we've flushed all events. */ | |
1669 | iterate_over_lwps (kill_wait_callback, NULL); | |
1670 | ||
1671 | target_mourn_inferior (); | |
1672 | } | |
1673 | ||
1674 | static void | |
1675 | lin_lwp_create_inferior (char *exec_file, char *allargs, char **env) | |
1676 | { | |
c194fbe1 | 1677 | child_ops.to_create_inferior (exec_file, allargs, env); |
fb0e1ba7 MK |
1678 | } |
1679 | ||
6949171e | 1680 | static void |
fb0e1ba7 MK |
1681 | lin_lwp_mourn_inferior (void) |
1682 | { | |
c194fbe1 | 1683 | trap_ptid = null_ptid; |
fb0e1ba7 | 1684 | |
c194fbe1 | 1685 | /* Destroy LWP info; it's no longer valid. */ |
fb0e1ba7 MK |
1686 | init_lwp_list (); |
1687 | ||
4c8de859 | 1688 | /* Restore the original signal mask. */ |
3f07c44b MK |
1689 | sigprocmask (SIG_SETMASK, &normal_mask, NULL); |
1690 | sigemptyset (&blocked_mask); | |
1691 | ||
c194fbe1 | 1692 | child_ops.to_mourn_inferior (); |
fb0e1ba7 MK |
1693 | } |
1694 | ||
fb0e1ba7 MK |
1695 | static int |
1696 | lin_lwp_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write, | |
6949171e | 1697 | struct mem_attrib *attrib, struct target_ops *target) |
fb0e1ba7 | 1698 | { |
39f77062 | 1699 | struct cleanup *old_chain = save_inferior_ptid (); |
fb0e1ba7 MK |
1700 | int xfer; |
1701 | ||
39f77062 KB |
1702 | if (is_lwp (inferior_ptid)) |
1703 | inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid)); | |
fb0e1ba7 | 1704 | |
eb784848 DJ |
1705 | xfer = linux_proc_xfer_memory (memaddr, myaddr, len, write, attrib, target); |
1706 | if (xfer == 0) | |
1707 | xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target); | |
fb0e1ba7 MK |
1708 | |
1709 | do_cleanups (old_chain); | |
1710 | return xfer; | |
1711 | } | |
1712 | ||
1713 | static int | |
39f77062 | 1714 | lin_lwp_thread_alive (ptid_t ptid) |
fb0e1ba7 | 1715 | { |
39f77062 | 1716 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 MK |
1717 | |
1718 | errno = 0; | |
39f77062 | 1719 | ptrace (PTRACE_PEEKUSER, GET_LWP (ptid), 0, 0); |
9fe7d6bf MS |
1720 | if (debug_lin_lwp) |
1721 | fprintf_unfiltered (gdb_stdlog, | |
1722 | "LLTA: PTRACE_PEEKUSER %s, 0, 0 (%s)\n", | |
6949171e | 1723 | target_pid_to_str (ptid), |
9fe7d6bf | 1724 | errno ? safe_strerror (errno) : "OK"); |
fb0e1ba7 MK |
1725 | if (errno) |
1726 | return 0; | |
1727 | ||
1728 | return 1; | |
1729 | } | |
1730 | ||
1731 | static char * | |
39f77062 | 1732 | lin_lwp_pid_to_str (ptid_t ptid) |
fb0e1ba7 MK |
1733 | { |
1734 | static char buf[64]; | |
1735 | ||
39f77062 | 1736 | if (is_lwp (ptid)) |
fb0e1ba7 | 1737 | { |
b08cfdb6 | 1738 | snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid)); |
fb0e1ba7 MK |
1739 | return buf; |
1740 | } | |
1741 | ||
39f77062 | 1742 | return normal_pid_to_str (ptid); |
fb0e1ba7 MK |
1743 | } |
1744 | ||
1745 | static void | |
1746 | init_lin_lwp_ops (void) | |
1747 | { | |
1748 | #if 0 | |
1749 | lin_lwp_ops.to_open = lin_lwp_open; | |
1750 | #endif | |
1751 | lin_lwp_ops.to_shortname = "lwp-layer"; | |
1752 | lin_lwp_ops.to_longname = "lwp-layer"; | |
1753 | lin_lwp_ops.to_doc = "Low level threads support (LWP layer)"; | |
1754 | lin_lwp_ops.to_attach = lin_lwp_attach; | |
1755 | lin_lwp_ops.to_detach = lin_lwp_detach; | |
1756 | lin_lwp_ops.to_resume = lin_lwp_resume; | |
1757 | lin_lwp_ops.to_wait = lin_lwp_wait; | |
02ae7771 AC |
1758 | /* fetch_inferior_registers and store_inferior_registers will |
1759 | honor the LWP id, so we can use them directly. */ | |
1760 | lin_lwp_ops.to_fetch_registers = fetch_inferior_registers; | |
1761 | lin_lwp_ops.to_store_registers = store_inferior_registers; | |
fb0e1ba7 MK |
1762 | lin_lwp_ops.to_xfer_memory = lin_lwp_xfer_memory; |
1763 | lin_lwp_ops.to_kill = lin_lwp_kill; | |
1764 | lin_lwp_ops.to_create_inferior = lin_lwp_create_inferior; | |
1765 | lin_lwp_ops.to_mourn_inferior = lin_lwp_mourn_inferior; | |
1766 | lin_lwp_ops.to_thread_alive = lin_lwp_thread_alive; | |
1767 | lin_lwp_ops.to_pid_to_str = lin_lwp_pid_to_str; | |
4de4c07c DJ |
1768 | lin_lwp_ops.to_post_startup_inferior = child_post_startup_inferior; |
1769 | lin_lwp_ops.to_post_attach = child_post_attach; | |
1770 | lin_lwp_ops.to_insert_fork_catchpoint = child_insert_fork_catchpoint; | |
1771 | lin_lwp_ops.to_insert_vfork_catchpoint = child_insert_vfork_catchpoint; | |
1772 | lin_lwp_ops.to_insert_exec_catchpoint = child_insert_exec_catchpoint; | |
1773 | ||
fb0e1ba7 MK |
1774 | lin_lwp_ops.to_stratum = thread_stratum; |
1775 | lin_lwp_ops.to_has_thread_control = tc_schedlock; | |
1776 | lin_lwp_ops.to_magic = OPS_MAGIC; | |
1777 | } | |
1778 | ||
1779 | static void | |
1780 | sigchld_handler (int signo) | |
1781 | { | |
1782 | /* Do nothing. The only reason for this handler is that it allows | |
1783 | us to use sigsuspend in lin_lwp_wait above to wait for the | |
1784 | arrival of a SIGCHLD. */ | |
1785 | } | |
1786 | ||
1787 | void | |
1788 | _initialize_lin_lwp (void) | |
1789 | { | |
1790 | struct sigaction action; | |
fb0e1ba7 MK |
1791 | |
1792 | extern void thread_db_init (struct target_ops *); | |
1793 | ||
1794 | init_lin_lwp_ops (); | |
1795 | add_target (&lin_lwp_ops); | |
1796 | thread_db_init (&lin_lwp_ops); | |
1797 | ||
4c8de859 | 1798 | /* Save the original signal mask. */ |
3f07c44b MK |
1799 | sigprocmask (SIG_SETMASK, NULL, &normal_mask); |
1800 | ||
fb0e1ba7 MK |
1801 | action.sa_handler = sigchld_handler; |
1802 | sigemptyset (&action.sa_mask); | |
1803 | action.sa_flags = 0; | |
1804 | sigaction (SIGCHLD, &action, NULL); | |
1805 | ||
3f07c44b MK |
1806 | /* Make sure we don't block SIGCHLD during a sigsuspend. */ |
1807 | sigprocmask (SIG_SETMASK, NULL, &suspend_mask); | |
fb0e1ba7 | 1808 | sigdelset (&suspend_mask, SIGCHLD); |
3f07c44b MK |
1809 | |
1810 | sigemptyset (&blocked_mask); | |
7ca673cd MS |
1811 | |
1812 | add_show_from_set (add_set_cmd ("lin-lwp", no_class, var_zinteger, | |
6949171e | 1813 | (char *) &debug_lin_lwp, |
8605d56e | 1814 | "Set debugging of GNU/Linux lwp module.\n\ |
6949171e | 1815 | Enables printf debugging output.\n", &setdebuglist), &showdebuglist); |
fb0e1ba7 MK |
1816 | } |
1817 | \f | |
1818 | ||
1819 | /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to | |
8605d56e AC |
1820 | the GNU/Linux Threads library and therefore doesn't really belong |
1821 | here. */ | |
fb0e1ba7 MK |
1822 | |
1823 | /* Read variable NAME in the target and return its value if found. | |
1824 | Otherwise return zero. It is assumed that the type of the variable | |
1825 | is `int'. */ | |
1826 | ||
1827 | static int | |
1828 | get_signo (const char *name) | |
1829 | { | |
1830 | struct minimal_symbol *ms; | |
1831 | int signo; | |
1832 | ||
1833 | ms = lookup_minimal_symbol (name, NULL, NULL); | |
1834 | if (ms == NULL) | |
1835 | return 0; | |
1836 | ||
1837 | if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (char *) &signo, | |
1838 | sizeof (signo)) != 0) | |
1839 | return 0; | |
1840 | ||
1841 | return signo; | |
1842 | } | |
1843 | ||
1844 | /* Return the set of signals used by the threads library in *SET. */ | |
1845 | ||
1846 | void | |
1847 | lin_thread_get_thread_signals (sigset_t *set) | |
1848 | { | |
3f07c44b MK |
1849 | struct sigaction action; |
1850 | int restart, cancel; | |
fb0e1ba7 MK |
1851 | |
1852 | sigemptyset (set); | |
1853 | ||
1854 | restart = get_signo ("__pthread_sig_restart"); | |
1855 | if (restart == 0) | |
1856 | return; | |
1857 | ||
1858 | cancel = get_signo ("__pthread_sig_cancel"); | |
1859 | if (cancel == 0) | |
1860 | return; | |
1861 | ||
1862 | sigaddset (set, restart); | |
1863 | sigaddset (set, cancel); | |
3f07c44b | 1864 | |
8605d56e AC |
1865 | /* The GNU/Linux Threads library makes terminating threads send a |
1866 | special "cancel" signal instead of SIGCHLD. Make sure we catch | |
1867 | those (to prevent them from terminating GDB itself, which is | |
1868 | likely to be their default action) and treat them the same way as | |
1869 | SIGCHLD. */ | |
3f07c44b MK |
1870 | |
1871 | action.sa_handler = sigchld_handler; | |
1872 | sigemptyset (&action.sa_mask); | |
1873 | action.sa_flags = 0; | |
1874 | sigaction (cancel, &action, NULL); | |
1875 | ||
1876 | /* We block the "cancel" signal throughout this code ... */ | |
1877 | sigaddset (&blocked_mask, cancel); | |
1878 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
1879 | ||
1880 | /* ... except during a sigsuspend. */ | |
1881 | sigdelset (&suspend_mask, cancel); | |
fb0e1ba7 | 1882 | } |