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