Commit | Line | Data |
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8605d56e | 1 | /* Multi-threaded debugging support for GNU/Linux (LWP layer). |
4e052eda | 2 | Copyright 2000, 2001 Free Software Foundation, Inc. |
fb0e1ba7 MK |
3 | |
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | #include "defs.h" | |
22 | ||
23 | #include "gdb_assert.h" | |
309367d4 | 24 | #include "gdb_string.h" |
fb0e1ba7 MK |
25 | #include <errno.h> |
26 | #include <signal.h> | |
27 | #include <sys/ptrace.h> | |
28 | #include "gdb_wait.h" | |
29 | ||
30 | #include "gdbthread.h" | |
31 | #include "inferior.h" | |
32 | #include "target.h" | |
4e052eda | 33 | #include "regcache.h" |
7ca673cd | 34 | #include "gdbcmd.h" |
fb0e1ba7 | 35 | |
7ca673cd | 36 | static int debug_lin_lwp; |
1b84163e | 37 | extern char *strsignal (int sig); |
fb0e1ba7 | 38 | |
8605d56e AC |
39 | /* On GNU/Linux there are no real LWP's. The closest thing to LWP's |
40 | are processes sharing the same VM space. A multi-threaded process | |
41 | is basically a group of such processes. However, such a grouping | |
42 | is almost entirely a user-space issue; the kernel doesn't enforce | |
43 | such a grouping at all (this might change in the future). In | |
44 | general, we'll rely on the threads library (i.e. the GNU/Linux | |
45 | Threads library) to provide such a grouping. | |
fb0e1ba7 MK |
46 | |
47 | It is perfectly well possible to write a multi-threaded application | |
48 | without the assistance of a threads library, by using the clone | |
49 | system call directly. This module should be able to give some | |
50 | rudimentary support for debugging such applications if developers | |
51 | specify the CLONE_PTRACE flag in the clone system call, and are | |
8605d56e | 52 | using the Linux kernel 2.4 or above. |
fb0e1ba7 | 53 | |
8605d56e AC |
54 | Note that there are some peculiarities in GNU/Linux that affect |
55 | this code: | |
fb0e1ba7 MK |
56 | |
57 | - In general one should specify the __WCLONE flag to waitpid in | |
3f07c44b MK |
58 | order to make it report events for any of the cloned processes |
59 | (and leave it out for the initial process). However, if a cloned | |
60 | process has exited the exit status is only reported if the | |
8605d56e AC |
61 | __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but |
62 | we cannot use it since GDB must work on older systems too. | |
fb0e1ba7 MK |
63 | |
64 | - When a traced, cloned process exits and is waited for by the | |
4c8de859 | 65 | debugger, the kernel reassigns it to the original parent and |
8605d56e AC |
66 | keeps it around as a "zombie". Somehow, the GNU/Linux Threads |
67 | library doesn't notice this, which leads to the "zombie problem": | |
68 | When debugged a multi-threaded process that spawns a lot of | |
69 | threads will run out of processes, even if the threads exit, | |
70 | because the "zombies" stay around. */ | |
fb0e1ba7 MK |
71 | |
72 | /* Structure describing a LWP. */ | |
73 | struct lwp_info | |
74 | { | |
75 | /* The process id of the LWP. This is a combination of the LWP id | |
76 | and overall process id. */ | |
39f77062 | 77 | ptid_t ptid; |
fb0e1ba7 | 78 | |
cacab7c4 MK |
79 | /* Non-zero if this LWP is cloned. In this context "cloned" means |
80 | that the LWP is reporting to its parent using a signal other than | |
81 | SIGCHLD. */ | |
82 | int cloned; | |
83 | ||
fb0e1ba7 MK |
84 | /* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report |
85 | it back yet). */ | |
86 | int signalled; | |
87 | ||
88 | /* Non-zero if this LWP is stopped. */ | |
89 | int stopped; | |
90 | ||
fce0e6e1 MK |
91 | /* Non-zero if this LWP will be/has been resumed. Note that an LWP |
92 | can be marked both as stopped and resumed at the same time. This | |
93 | happens if we try to resume an LWP that has a wait status | |
94 | pending. We shouldn't let the LWP run until that wait status has | |
95 | been processed, but we should not report that wait status if GDB | |
96 | didn't try to let the LWP run. */ | |
97 | int resumed; | |
98 | ||
fb0e1ba7 MK |
99 | /* If non-zero, a pending wait status. */ |
100 | int status; | |
101 | ||
102 | /* Non-zero if we were stepping this LWP. */ | |
103 | int step; | |
104 | ||
105 | /* Next LWP in list. */ | |
106 | struct lwp_info *next; | |
107 | }; | |
108 | ||
109 | /* List of known LWPs. */ | |
110 | static struct lwp_info *lwp_list; | |
111 | ||
112 | /* Number of LWPs in the list. */ | |
113 | static int num_lwps; | |
114 | ||
115 | /* Non-zero if we're running in "threaded" mode. */ | |
116 | static int threaded; | |
117 | \f | |
118 | ||
ca6724c1 KB |
119 | #define GET_LWP(ptid) ptid_get_lwp (ptid) |
120 | #define GET_PID(ptid) ptid_get_pid (ptid) | |
121 | #define is_lwp(ptid) (GET_LWP (ptid) != 0) | |
122 | #define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0) | |
fb0e1ba7 | 123 | |
fb0e1ba7 MK |
124 | /* If the last reported event was a SIGTRAP, this variable is set to |
125 | the process id of the LWP/thread that got it. */ | |
39f77062 | 126 | ptid_t trap_ptid; |
fb0e1ba7 MK |
127 | \f |
128 | ||
129 | /* This module's target-specific operations. */ | |
130 | static struct target_ops lin_lwp_ops; | |
131 | ||
132 | /* The standard child operations. */ | |
133 | extern struct target_ops child_ops; | |
134 | ||
3f07c44b MK |
135 | /* Since we cannot wait (in lin_lwp_wait) for the initial process and |
136 | any cloned processes with a single call to waitpid, we have to use | |
4c8de859 | 137 | the WNOHANG flag and call waitpid in a loop. To optimize |
3f07c44b MK |
138 | things a bit we use `sigsuspend' to wake us up when a process has |
139 | something to report (it will send us a SIGCHLD if it has). To make | |
140 | this work we have to juggle with the signal mask. We save the | |
4c8de859 | 141 | original signal mask such that we can restore it before creating a |
3f07c44b MK |
142 | new process in order to avoid blocking certain signals in the |
143 | inferior. We then block SIGCHLD during the waitpid/sigsuspend | |
144 | loop. */ | |
145 | ||
4c8de859 | 146 | /* Original signal mask. */ |
3f07c44b MK |
147 | static sigset_t normal_mask; |
148 | ||
fb0e1ba7 MK |
149 | /* Signal mask for use with sigsuspend in lin_lwp_wait, initialized in |
150 | _initialize_lin_lwp. */ | |
151 | static sigset_t suspend_mask; | |
3f07c44b MK |
152 | |
153 | /* Signals to block to make that sigsuspend work. */ | |
154 | static sigset_t blocked_mask; | |
fb0e1ba7 MK |
155 | \f |
156 | ||
157 | /* Prototypes for local functions. */ | |
c194fbe1 | 158 | static int stop_wait_callback (struct lwp_info *lp, void *data); |
fb0e1ba7 | 159 | \f |
58eeadba MK |
160 | /* Convert wait status STATUS to a string. Used for printing debug |
161 | messages only. */ | |
fb0e1ba7 | 162 | |
58eeadba MK |
163 | static char * |
164 | status_to_str (int status) | |
165 | { | |
166 | static char buf[64]; | |
167 | ||
168 | if (WIFSTOPPED (status)) | |
169 | snprintf (buf, sizeof (buf), "%s (stopped)", | |
170 | strsignal (WSTOPSIG (status))); | |
171 | else if (WIFSIGNALED (status)) | |
172 | snprintf (buf, sizeof (buf), "%s (terminated)", | |
173 | strsignal (WSTOPSIG (status))); | |
174 | else | |
175 | snprintf (buf, sizeof (buf), "%d (exited)", | |
176 | WEXITSTATUS (status)); | |
177 | ||
178 | return buf; | |
179 | } | |
180 | \f | |
c194fbe1 MK |
181 | /* Initialize the list of LWPs. Note that this module, contrary to |
182 | what GDB's generic threads layer does for its thread list, | |
183 | re-initializes the LWP lists whenever we mourn or detach (which | |
184 | doesn't involve mourning) the inferior. */ | |
fb0e1ba7 MK |
185 | |
186 | static void | |
187 | init_lwp_list (void) | |
188 | { | |
189 | struct lwp_info *lp, *lpnext; | |
190 | ||
191 | for (lp = lwp_list; lp; lp = lpnext) | |
192 | { | |
193 | lpnext = lp->next; | |
b8c9b27d | 194 | xfree (lp); |
fb0e1ba7 MK |
195 | } |
196 | ||
197 | lwp_list = NULL; | |
198 | num_lwps = 0; | |
199 | threaded = 0; | |
200 | } | |
201 | ||
202 | /* Add the LWP specified by PID to the list. If this causes the | |
203 | number of LWPs to become larger than one, go into "threaded" mode. | |
204 | Return a pointer to the structure describing the new LWP. */ | |
205 | ||
206 | static struct lwp_info * | |
39f77062 | 207 | add_lwp (ptid_t ptid) |
fb0e1ba7 MK |
208 | { |
209 | struct lwp_info *lp; | |
210 | ||
39f77062 | 211 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 MK |
212 | |
213 | lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info)); | |
214 | ||
215 | memset (lp, 0, sizeof (struct lwp_info)); | |
216 | ||
39f77062 | 217 | lp->ptid = ptid; |
fb0e1ba7 MK |
218 | |
219 | lp->next = lwp_list; | |
220 | lwp_list = lp; | |
221 | if (++num_lwps > 1) | |
222 | threaded = 1; | |
223 | ||
224 | return lp; | |
225 | } | |
226 | ||
227 | /* Remove the LWP specified by PID from the list. */ | |
228 | ||
229 | static void | |
39f77062 | 230 | delete_lwp (ptid_t ptid) |
fb0e1ba7 MK |
231 | { |
232 | struct lwp_info *lp, *lpprev; | |
233 | ||
234 | lpprev = NULL; | |
235 | ||
236 | for (lp = lwp_list; lp; lpprev = lp, lp = lp->next) | |
39f77062 | 237 | if (ptid_equal (lp->ptid, ptid)) |
fb0e1ba7 MK |
238 | break; |
239 | ||
240 | if (!lp) | |
241 | return; | |
242 | ||
243 | /* We don't go back to "non-threaded" mode if the number of threads | |
244 | becomes less than two. */ | |
245 | num_lwps--; | |
246 | ||
247 | if (lpprev) | |
248 | lpprev->next = lp->next; | |
249 | else | |
250 | lwp_list = lp->next; | |
251 | ||
b8c9b27d | 252 | xfree (lp); |
fb0e1ba7 MK |
253 | } |
254 | ||
255 | /* Return a pointer to the structure describing the LWP corresponding | |
256 | to PID. If no corresponding LWP could be found, return NULL. */ | |
257 | ||
258 | static struct lwp_info * | |
39f77062 | 259 | find_lwp_pid (ptid_t ptid) |
fb0e1ba7 MK |
260 | { |
261 | struct lwp_info *lp; | |
39f77062 | 262 | int lwp; |
fb0e1ba7 | 263 | |
39f77062 KB |
264 | if (is_lwp (ptid)) |
265 | lwp = GET_LWP (ptid); | |
266 | else | |
267 | lwp = GET_PID (ptid); | |
fb0e1ba7 MK |
268 | |
269 | for (lp = lwp_list; lp; lp = lp->next) | |
39f77062 | 270 | if (lwp == GET_LWP (lp->ptid)) |
fb0e1ba7 MK |
271 | return lp; |
272 | ||
273 | return NULL; | |
274 | } | |
275 | ||
276 | /* Call CALLBACK with its second argument set to DATA for every LWP in | |
277 | the list. If CALLBACK returns 1 for a particular LWP, return a | |
278 | pointer to the structure describing that LWP immediately. | |
279 | Otherwise return NULL. */ | |
280 | ||
281 | struct lwp_info * | |
282 | iterate_over_lwps (int (*callback) (struct lwp_info *, void *), void *data) | |
283 | { | |
fce0e6e1 | 284 | struct lwp_info *lp, *lpnext; |
fb0e1ba7 | 285 | |
fce0e6e1 MK |
286 | for (lp = lwp_list; lp; lp = lpnext) |
287 | { | |
288 | lpnext = lp->next; | |
289 | if ((*callback) (lp, data)) | |
290 | return lp; | |
291 | } | |
fb0e1ba7 MK |
292 | |
293 | return NULL; | |
294 | } | |
295 | \f | |
296 | ||
8605d56e | 297 | /* Implementation of the PREPARE_TO_PROCEED hook for the GNU/Linux LWP |
e02bc4cc DS |
298 | layer. |
299 | ||
300 | Note that this implementation is potentially redundant now that | |
8849f47d JL |
301 | default_prepare_to_proceed() has been added. |
302 | ||
303 | FIXME This may not support switching threads after Ctrl-C | |
304 | correctly. The default implementation does support this. */ | |
fb0e1ba7 MK |
305 | |
306 | int | |
307 | lin_lwp_prepare_to_proceed (void) | |
308 | { | |
39f77062 KB |
309 | if (! ptid_equal (trap_ptid, null_ptid) |
310 | && ! ptid_equal (inferior_ptid, trap_ptid)) | |
fb0e1ba7 MK |
311 | { |
312 | /* Switched over from TRAP_PID. */ | |
313 | CORE_ADDR stop_pc = read_pc (); | |
314 | CORE_ADDR trap_pc; | |
315 | ||
316 | /* Avoid switching where it wouldn't do any good, i.e. if both | |
317 | threads are at the same breakpoint. */ | |
39f77062 | 318 | trap_pc = read_pc_pid (trap_ptid); |
fb0e1ba7 MK |
319 | if (trap_pc != stop_pc && breakpoint_here_p (trap_pc)) |
320 | { | |
321 | /* User hasn't deleted the breakpoint. Return non-zero, and | |
322 | switch back to TRAP_PID. */ | |
39f77062 | 323 | inferior_ptid = trap_ptid; |
fb0e1ba7 MK |
324 | |
325 | /* FIXME: Is this stuff really necessary? */ | |
326 | flush_cached_frames (); | |
327 | registers_changed (); | |
328 | ||
329 | return 1; | |
330 | } | |
331 | } | |
332 | ||
333 | return 0; | |
334 | } | |
335 | \f | |
336 | ||
337 | #if 0 | |
338 | static void | |
339 | lin_lwp_open (char *args, int from_tty) | |
340 | { | |
341 | push_target (&lin_lwp_ops); | |
342 | } | |
343 | #endif | |
344 | ||
345 | /* Attach to the LWP specified by PID. If VERBOSE is non-zero, print | |
346 | a message telling the user that a new LWP has been added to the | |
347 | process. */ | |
348 | ||
349 | void | |
39f77062 | 350 | lin_lwp_attach_lwp (ptid_t ptid, int verbose) |
fb0e1ba7 MK |
351 | { |
352 | struct lwp_info *lp; | |
353 | ||
39f77062 | 354 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 | 355 | |
da9c7185 KB |
356 | /* Make sure SIGCHLD is blocked. We don't want SIGCHLD events |
357 | to interrupt either the ptrace() or waitpid() calls below. */ | |
358 | if (! sigismember (&blocked_mask, SIGCHLD)) | |
359 | { | |
360 | sigaddset (&blocked_mask, SIGCHLD); | |
361 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
362 | } | |
363 | ||
fb0e1ba7 | 364 | if (verbose) |
39f77062 | 365 | printf_filtered ("[New %s]\n", target_pid_to_str (ptid)); |
fb0e1ba7 | 366 | |
c194fbe1 MK |
367 | lp = find_lwp_pid (ptid); |
368 | if (lp == NULL) | |
369 | lp = add_lwp (ptid); | |
370 | ||
cacab7c4 MK |
371 | /* We assume that we're already attached to any LWP that has an |
372 | id equal to the overall process id. */ | |
373 | if (GET_LWP (ptid) != GET_PID (ptid)) | |
c4365b19 | 374 | { |
cacab7c4 MK |
375 | pid_t pid; |
376 | int status; | |
377 | ||
378 | if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0) | |
379 | error ("Can't attach %s: %s", target_pid_to_str (ptid), | |
dc672865 | 380 | safe_strerror (errno)); |
cacab7c4 MK |
381 | |
382 | pid = waitpid (GET_LWP (ptid), &status, 0); | |
383 | if (pid == -1 && errno == ECHILD) | |
384 | { | |
385 | /* Try again with __WCLONE to check cloned processes. */ | |
386 | pid = waitpid (GET_LWP (ptid), &status, __WCLONE); | |
387 | lp->cloned = 1; | |
388 | } | |
389 | ||
390 | gdb_assert (pid == GET_LWP (ptid) | |
391 | && WIFSTOPPED (status) && WSTOPSIG (status)); | |
392 | ||
393 | lp->stopped = 1; | |
c4365b19 | 394 | } |
da9c7185 KB |
395 | else |
396 | { | |
397 | /* We assume that the LWP representing the original process | |
398 | is already stopped. Mark it as stopped in the data structure | |
399 | that the lin-lwp layer uses to keep track of threads. Note | |
400 | that this won't have already been done since the main thread | |
401 | will have, we assume, been stopped by an attach from a | |
402 | different layer. */ | |
403 | lp->stopped = 1; | |
404 | } | |
fb0e1ba7 MK |
405 | } |
406 | ||
407 | static void | |
408 | lin_lwp_attach (char *args, int from_tty) | |
409 | { | |
c194fbe1 | 410 | struct lwp_info *lp; |
cacab7c4 MK |
411 | pid_t pid; |
412 | int status; | |
c194fbe1 | 413 | |
fb0e1ba7 MK |
414 | /* FIXME: We should probably accept a list of process id's, and |
415 | attach all of them. */ | |
c194fbe1 MK |
416 | child_ops.to_attach (args, from_tty); |
417 | ||
418 | /* Add the initial process as the first LWP to the list. */ | |
cacab7c4 | 419 | lp = add_lwp (BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid))); |
c194fbe1 MK |
420 | |
421 | /* Make sure the initial process is stopped. The user-level threads | |
422 | layer might want to poke around in the inferior, and that won't | |
423 | work if things haven't stabilized yet. */ | |
cacab7c4 MK |
424 | pid = waitpid (GET_PID (inferior_ptid), &status, 0); |
425 | if (pid == -1 && errno == ECHILD) | |
426 | { | |
427 | warning ("%s is a cloned process", target_pid_to_str (inferior_ptid)); | |
428 | ||
429 | /* Try again with __WCLONE to check cloned processes. */ | |
430 | pid = waitpid (GET_PID (inferior_ptid), &status, __WCLONE); | |
431 | lp->cloned = 1; | |
432 | } | |
433 | ||
434 | gdb_assert (pid == GET_PID (inferior_ptid) | |
435 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP); | |
436 | ||
437 | lp->stopped = 1; | |
c194fbe1 MK |
438 | |
439 | /* Fake the SIGSTOP that core GDB expects. */ | |
440 | lp->status = W_STOPCODE (SIGSTOP); | |
fce0e6e1 | 441 | lp->resumed = 1; |
c194fbe1 MK |
442 | } |
443 | ||
444 | static int | |
445 | detach_callback (struct lwp_info *lp, void *data) | |
446 | { | |
447 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); | |
448 | ||
449 | if (debug_lin_lwp && lp->status) | |
b08cfdb6 | 450 | fprintf_unfiltered (gdb_stdlog, "Pending %s for LWP %ld on detach.\n", |
c194fbe1 MK |
451 | strsignal (WSTOPSIG (lp->status)), GET_LWP (lp->ptid)); |
452 | ||
453 | while (lp->signalled && lp->stopped) | |
454 | { | |
455 | if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, | |
456 | WSTOPSIG (lp->status)) < 0) | |
457 | error ("Can't continue %s: %s", target_pid_to_str (lp->ptid), | |
dc672865 | 458 | safe_strerror (errno)); |
c194fbe1 MK |
459 | |
460 | lp->stopped = 0; | |
c4365b19 | 461 | lp->signalled = 0; |
c194fbe1 MK |
462 | lp->status = 0; |
463 | stop_wait_callback (lp, NULL); | |
464 | ||
465 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); | |
466 | } | |
467 | ||
cacab7c4 MK |
468 | /* We don't actually detach from the LWP that has an id equal to the |
469 | overall process id just yet. */ | |
470 | if (GET_LWP (lp->ptid) != GET_PID (lp->ptid)) | |
c194fbe1 MK |
471 | { |
472 | if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0, | |
473 | WSTOPSIG (lp->status)) < 0) | |
474 | error ("Can't detach %s: %s", target_pid_to_str (lp->ptid), | |
dc672865 | 475 | safe_strerror (errno)); |
c194fbe1 MK |
476 | |
477 | delete_lwp (lp->ptid); | |
478 | } | |
479 | ||
480 | return 0; | |
fb0e1ba7 MK |
481 | } |
482 | ||
483 | static void | |
484 | lin_lwp_detach (char *args, int from_tty) | |
485 | { | |
c194fbe1 MK |
486 | iterate_over_lwps (detach_callback, NULL); |
487 | ||
cacab7c4 | 488 | /* Only the initial process should be left right now. */ |
c194fbe1 MK |
489 | gdb_assert (num_lwps == 1); |
490 | ||
491 | trap_ptid = null_ptid; | |
492 | ||
493 | /* Destroy LWP info; it's no longer valid. */ | |
494 | init_lwp_list (); | |
495 | ||
496 | /* Restore the original signal mask. */ | |
497 | sigprocmask (SIG_SETMASK, &normal_mask, NULL); | |
498 | sigemptyset (&blocked_mask); | |
499 | ||
01263b57 | 500 | inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid)); |
c194fbe1 | 501 | child_ops.to_detach (args, from_tty); |
fb0e1ba7 MK |
502 | } |
503 | \f | |
504 | ||
505 | struct private_thread_info | |
506 | { | |
507 | int lwpid; | |
508 | }; | |
509 | ||
510 | /* Return non-zero if TP corresponds to the LWP specified by DATA | |
511 | (which is assumed to be a pointer to a `struct lwp_info'. */ | |
512 | ||
513 | static int | |
514 | find_lwp_callback (struct thread_info *tp, void *data) | |
515 | { | |
516 | struct lwp_info *lp = data; | |
517 | ||
39f77062 | 518 | if (tp->private->lwpid == GET_LWP (lp->ptid)) |
fb0e1ba7 MK |
519 | return 1; |
520 | ||
521 | return 0; | |
522 | } | |
523 | ||
524 | /* Resume LP. */ | |
525 | ||
526 | static int | |
527 | resume_callback (struct lwp_info *lp, void *data) | |
528 | { | |
529 | if (lp->stopped && lp->status == 0) | |
530 | { | |
531 | struct thread_info *tp; | |
532 | ||
b1aeb4c5 | 533 | #if 0 |
fb0e1ba7 MK |
534 | /* FIXME: kettenis/2000-08-26: This should really be handled |
535 | properly by core GDB. */ | |
536 | ||
39f77062 | 537 | tp = find_thread_pid (lp->ptid); |
fb0e1ba7 MK |
538 | if (tp == NULL) |
539 | tp = iterate_over_threads (find_lwp_callback, lp); | |
540 | gdb_assert (tp); | |
541 | ||
542 | /* If we were previously stepping the thread, and now continue | |
543 | the thread we must invalidate the stepping range. However, | |
544 | if there is a step_resume breakpoint for this thread, we must | |
545 | preserve the stepping range to make it possible to continue | |
546 | stepping once we hit it. */ | |
547 | if (tp->step_range_end && tp->step_resume_breakpoint == NULL) | |
548 | { | |
549 | gdb_assert (lp->step); | |
550 | tp->step_range_start = tp->step_range_end = 0; | |
551 | } | |
552 | #endif | |
553 | ||
39f77062 | 554 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0); |
fb0e1ba7 MK |
555 | lp->stopped = 0; |
556 | lp->step = 0; | |
557 | } | |
558 | ||
559 | return 0; | |
560 | } | |
561 | ||
fce0e6e1 MK |
562 | static int |
563 | resume_clear_callback (struct lwp_info *lp, void *data) | |
564 | { | |
565 | lp->resumed = 0; | |
566 | return 0; | |
567 | } | |
568 | ||
569 | static int | |
570 | resume_set_callback (struct lwp_info *lp, void *data) | |
571 | { | |
572 | lp->resumed = 1; | |
573 | return 0; | |
574 | } | |
575 | ||
fb0e1ba7 | 576 | static void |
39f77062 | 577 | lin_lwp_resume (ptid_t ptid, int step, enum target_signal signo) |
fb0e1ba7 MK |
578 | { |
579 | struct lwp_info *lp; | |
580 | int resume_all; | |
581 | ||
2a4b7c45 DJ |
582 | /* A specific PTID means `step only this process id'. */ |
583 | resume_all = (PIDGET (ptid) == -1); | |
fb0e1ba7 | 584 | |
fce0e6e1 MK |
585 | if (resume_all) |
586 | iterate_over_lwps (resume_set_callback, NULL); | |
587 | else | |
588 | iterate_over_lwps (resume_clear_callback, NULL); | |
589 | ||
fb0e1ba7 | 590 | /* If PID is -1, it's the current inferior that should be |
c4365b19 | 591 | handled specially. */ |
39f77062 KB |
592 | if (PIDGET (ptid) == -1) |
593 | ptid = inferior_ptid; | |
fb0e1ba7 | 594 | |
39f77062 | 595 | lp = find_lwp_pid (ptid); |
fb0e1ba7 MK |
596 | if (lp) |
597 | { | |
39f77062 | 598 | ptid = pid_to_ptid (GET_LWP (lp->ptid)); |
fb0e1ba7 | 599 | |
fb0e1ba7 MK |
600 | /* Remember if we're stepping. */ |
601 | lp->step = step; | |
602 | ||
fce0e6e1 MK |
603 | /* Mark this LWP as resumed. */ |
604 | lp->resumed = 1; | |
605 | ||
fb0e1ba7 MK |
606 | /* If we have a pending wait status for this thread, there is no |
607 | point in resuming the process. */ | |
608 | if (lp->status) | |
609 | { | |
610 | /* FIXME: What should we do if we are supposed to continue | |
611 | this thread with a signal? */ | |
612 | gdb_assert (signo == TARGET_SIGNAL_0); | |
613 | return; | |
614 | } | |
40564aca MK |
615 | |
616 | /* Mark LWP as not stopped to prevent it from being continued by | |
617 | resume_callback. */ | |
618 | lp->stopped = 0; | |
fb0e1ba7 MK |
619 | } |
620 | ||
621 | if (resume_all) | |
622 | iterate_over_lwps (resume_callback, NULL); | |
623 | ||
39f77062 | 624 | child_resume (ptid, step, signo); |
fb0e1ba7 MK |
625 | } |
626 | \f | |
627 | ||
628 | /* Send a SIGSTOP to LP. */ | |
629 | ||
630 | static int | |
631 | stop_callback (struct lwp_info *lp, void *data) | |
632 | { | |
633 | if (! lp->stopped && ! lp->signalled) | |
634 | { | |
635 | int ret; | |
636 | ||
39f77062 | 637 | ret = kill (GET_LWP (lp->ptid), SIGSTOP); |
fb0e1ba7 MK |
638 | gdb_assert (ret == 0); |
639 | ||
640 | lp->signalled = 1; | |
641 | gdb_assert (lp->status == 0); | |
642 | } | |
643 | ||
644 | return 0; | |
645 | } | |
646 | ||
de4ca854 MK |
647 | /* Wait until LP is stopped. If DATA is non-null it is interpreted as |
648 | a pointer to a set of signals to be flushed immediately. */ | |
fb0e1ba7 MK |
649 | |
650 | static int | |
651 | stop_wait_callback (struct lwp_info *lp, void *data) | |
652 | { | |
de4ca854 MK |
653 | sigset_t *flush_mask = data; |
654 | ||
fb0e1ba7 MK |
655 | if (! lp->stopped && lp->signalled) |
656 | { | |
657 | pid_t pid; | |
658 | int status; | |
659 | ||
660 | gdb_assert (lp->status == 0); | |
661 | ||
cacab7c4 | 662 | pid = waitpid (GET_LWP (lp->ptid), &status, lp->cloned ? __WCLONE : 0); |
fb0e1ba7 MK |
663 | if (pid == -1 && errno == ECHILD) |
664 | /* OK, the proccess has disappeared. We'll catch the actual | |
3f07c44b | 665 | exit event in lin_lwp_wait. */ |
fb0e1ba7 MK |
666 | return 0; |
667 | ||
39f77062 | 668 | gdb_assert (pid == GET_LWP (lp->ptid)); |
fb0e1ba7 MK |
669 | |
670 | if (WIFEXITED (status) || WIFSIGNALED (status)) | |
671 | { | |
672 | gdb_assert (num_lwps > 1); | |
fb0e1ba7 | 673 | |
39f77062 | 674 | if (in_thread_list (lp->ptid)) |
e6328671 MK |
675 | { |
676 | /* Core GDB cannot deal with us deleting the current | |
677 | thread. */ | |
39f77062 KB |
678 | if (!ptid_equal (lp->ptid, inferior_ptid)) |
679 | delete_thread (lp->ptid); | |
e6328671 | 680 | printf_unfiltered ("[%s exited]\n", |
39f77062 | 681 | target_pid_to_str (lp->ptid)); |
e6328671 | 682 | } |
7ca673cd | 683 | if (debug_lin_lwp) |
9085700c | 684 | fprintf_unfiltered (gdb_stdlog, |
39f77062 | 685 | "%s exited.\n", target_pid_to_str (lp->ptid)); |
7ca673cd | 686 | |
39f77062 | 687 | delete_lwp (lp->ptid); |
fb0e1ba7 MK |
688 | return 0; |
689 | } | |
690 | ||
691 | gdb_assert (WIFSTOPPED (status)); | |
fb0e1ba7 | 692 | |
de4ca854 MK |
693 | /* Ignore any signals in FLUSH_MASK. */ |
694 | if (flush_mask && sigismember (flush_mask, WSTOPSIG (status))) | |
695 | { | |
696 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
697 | return stop_wait_callback (lp, flush_mask); | |
698 | } | |
699 | ||
fb0e1ba7 MK |
700 | if (WSTOPSIG (status) != SIGSTOP) |
701 | { | |
b1aeb4c5 | 702 | if (WSTOPSIG (status) == SIGTRAP) |
fb0e1ba7 MK |
703 | { |
704 | /* If a LWP other than the LWP that we're reporting an | |
705 | event for has hit a GDB breakpoint (as opposed to | |
706 | some random trap signal), then just arrange for it to | |
707 | hit it again later. We don't keep the SIGTRAP status | |
708 | and don't forward the SIGTRAP signal to the LWP. We | |
709 | will handle the current event, eventually we will | |
710 | resume all LWPs, and this one will get its breakpoint | |
711 | trap again. | |
712 | ||
713 | If we do not do this, then we run the risk that the | |
714 | user will delete or disable the breakpoint, but the | |
715 | thread will have already tripped on it. */ | |
7ca673cd | 716 | |
c4365b19 MS |
717 | /* Now resume this LWP and get the SIGSTOP event. */ |
718 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
b1aeb4c5 MS |
719 | if (debug_lin_lwp) |
720 | { | |
721 | fprintf_unfiltered (gdb_stderr, | |
722 | "SWC: Candidate SIGTRAP event in %ld\n", | |
723 | GET_LWP (lp->ptid)); | |
724 | } | |
725 | /* Hold the SIGTRAP for handling by lin_lwp_wait. */ | |
726 | stop_wait_callback (lp, data); | |
727 | /* If there's another event, throw it back into the queue. */ | |
728 | if (lp->status) | |
729 | kill (GET_LWP (lp->ptid), WSTOPSIG (lp->status)); | |
730 | /* Save the sigtrap event. */ | |
731 | lp->status = status; | |
732 | return 0; | |
fb0e1ba7 MK |
733 | } |
734 | else | |
735 | { | |
b1aeb4c5 MS |
736 | /* The thread was stopped with a signal other than |
737 | SIGSTOP, and didn't accidentally trip a breakpoint. */ | |
738 | ||
7ca673cd | 739 | if (debug_lin_lwp) |
b1aeb4c5 MS |
740 | { |
741 | fprintf_unfiltered (gdb_stderr, | |
742 | "SWC: Pending event %d in %ld\n", | |
743 | WSTOPSIG (status), GET_LWP (lp->ptid)); | |
744 | } | |
745 | /* Now resume this LWP and get the SIGSTOP event. */ | |
746 | ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0); | |
7ca673cd | 747 | |
b1aeb4c5 MS |
748 | /* Hold this event/waitstatus while we check to see if |
749 | there are any more (we still want to get that SIGSTOP). */ | |
750 | stop_wait_callback (lp, data); | |
751 | /* If the lp->status field is still empty, use it to hold | |
752 | this event. If not, then this event must be returned | |
753 | to the event queue of the LWP. */ | |
754 | if (lp->status == 0) | |
755 | lp->status = status; | |
756 | else | |
757 | kill (GET_LWP (lp->ptid), WSTOPSIG (status)); | |
758 | return 0; | |
fb0e1ba7 MK |
759 | } |
760 | } | |
761 | else | |
762 | { | |
763 | /* We caught the SIGSTOP that we intended to catch, so | |
764 | there's no SIGSTOP pending. */ | |
b1aeb4c5 | 765 | lp->stopped = 1; |
fb0e1ba7 MK |
766 | lp->signalled = 0; |
767 | } | |
768 | } | |
769 | ||
770 | return 0; | |
771 | } | |
772 | ||
773 | /* Return non-zero if LP has a wait status pending. */ | |
774 | ||
775 | static int | |
776 | status_callback (struct lwp_info *lp, void *data) | |
777 | { | |
fce0e6e1 MK |
778 | /* Only report a pending wait status if we pretend that this has |
779 | indeed been resumed. */ | |
780 | return (lp->status != 0 && lp->resumed); | |
fb0e1ba7 MK |
781 | } |
782 | ||
783 | /* Return non-zero if LP isn't stopped. */ | |
784 | ||
785 | static int | |
786 | running_callback (struct lwp_info *lp, void *data) | |
787 | { | |
788 | return (lp->stopped == 0); | |
789 | } | |
790 | ||
00d4fce6 | 791 | /* Count the LWP's that have had events. */ |
b1aeb4c5 MS |
792 | |
793 | static int | |
794 | count_events_callback (struct lwp_info *lp, void *data) | |
795 | { | |
796 | int *count = data; | |
797 | ||
00d4fce6 MK |
798 | gdb_assert (count != NULL); |
799 | ||
800 | /* Count only LWPs that have a SIGTRAP event pending. */ | |
801 | if (lp->status != 0 | |
802 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) | |
b1aeb4c5 MS |
803 | (*count)++; |
804 | ||
805 | return 0; | |
806 | } | |
807 | ||
00d4fce6 | 808 | /* Select the LWP (if any) that is currently being single-stepped. */ |
b1aeb4c5 MS |
809 | |
810 | static int | |
811 | select_singlestep_lwp_callback (struct lwp_info *lp, void *data) | |
812 | { | |
813 | if (lp->step && lp->status != 0) | |
814 | return 1; | |
815 | else | |
816 | return 0; | |
817 | } | |
818 | ||
00d4fce6 | 819 | /* Select the Nth LWP that has had a SIGTRAP event. */ |
b1aeb4c5 MS |
820 | |
821 | static int | |
822 | select_event_lwp_callback (struct lwp_info *lp, void *data) | |
823 | { | |
824 | int *selector = data; | |
825 | ||
00d4fce6 MK |
826 | gdb_assert (selector != NULL); |
827 | ||
828 | /* Select only LWPs that have a SIGTRAP event pending. */ | |
829 | if (lp->status != 0 | |
830 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP) | |
b1aeb4c5 MS |
831 | if ((*selector)-- == 0) |
832 | return 1; | |
833 | ||
834 | return 0; | |
835 | } | |
836 | ||
837 | static int | |
838 | cancel_breakpoints_callback (struct lwp_info *lp, void *data) | |
839 | { | |
840 | struct lwp_info *event_lp = data; | |
841 | ||
00d4fce6 MK |
842 | /* Leave the LWP that has been elected to receive a SIGTRAP alone. */ |
843 | if (lp == event_lp) | |
844 | return 0; | |
845 | ||
846 | /* If a LWP other than the LWP that we're reporting an event for has | |
847 | hit a GDB breakpoint (as opposed to some random trap signal), | |
848 | then just arrange for it to hit it again later. We don't keep | |
849 | the SIGTRAP status and don't forward the SIGTRAP signal to the | |
850 | LWP. We will handle the current event, eventually we will resume | |
851 | all LWPs, and this one will get its breakpoint trap again. | |
852 | ||
853 | If we do not do this, then we run the risk that the user will | |
854 | delete or disable the breakpoint, but the LWP will have already | |
855 | tripped on it. */ | |
856 | ||
857 | if (lp->status != 0 | |
858 | && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP | |
859 | && breakpoint_inserted_here_p (read_pc_pid (lp->ptid) - | |
860 | DECR_PC_AFTER_BREAK)) | |
b1aeb4c5 MS |
861 | { |
862 | if (debug_lin_lwp) | |
00d4fce6 MK |
863 | fprintf_unfiltered (gdb_stdlog, |
864 | "Push back breakpoint for LWP %ld\n", | |
865 | GET_LWP (lp->ptid)); | |
866 | ||
867 | /* Back up the PC if necessary. */ | |
b1aeb4c5 | 868 | if (DECR_PC_AFTER_BREAK) |
00d4fce6 MK |
869 | write_pc_pid (read_pc_pid (lp->ptid) - DECR_PC_AFTER_BREAK, lp->ptid); |
870 | ||
871 | /* Throw away the SIGTRAP. */ | |
b1aeb4c5 MS |
872 | lp->status = 0; |
873 | } | |
00d4fce6 | 874 | |
b1aeb4c5 MS |
875 | return 0; |
876 | } | |
877 | ||
00d4fce6 | 878 | /* Select one LWP out of those that have events pending. */ |
b1aeb4c5 MS |
879 | |
880 | static void | |
881 | select_event_lwp (struct lwp_info **orig_lp, int *status) | |
882 | { | |
883 | int num_events = 0; | |
884 | int random_selector; | |
885 | struct lwp_info *event_lp; | |
886 | ||
00d4fce6 MK |
887 | /* Record the wait status for the origional LWP. */ |
888 | (*orig_lp)->status = *status; | |
889 | ||
890 | /* Give preference to any LWP that is being single-stepped. */ | |
b1aeb4c5 MS |
891 | event_lp = iterate_over_lwps (select_singlestep_lwp_callback, NULL); |
892 | if (event_lp != NULL) | |
893 | { | |
894 | if (debug_lin_lwp) | |
00d4fce6 MK |
895 | fprintf_unfiltered (gdb_stdlog, |
896 | "Select single-step LWP %ld\n", | |
b1aeb4c5 MS |
897 | GET_LWP (event_lp->ptid)); |
898 | } | |
899 | else | |
900 | { | |
901 | /* No single-stepping LWP. Select one at random, out of those | |
00d4fce6 | 902 | which have had SIGTRAP events. */ |
b1aeb4c5 | 903 | |
00d4fce6 MK |
904 | /* First see how many SIGTRAP events we have. */ |
905 | iterate_over_lwps (count_events_callback, &num_events); | |
b1aeb4c5 | 906 | |
00d4fce6 MK |
907 | /* Now randomly pick a LWP out of those that have had a SIGTRAP. */ |
908 | random_selector = (int) | |
b1aeb4c5 MS |
909 | ((num_events * (double) rand ()) / (RAND_MAX + 1.0)); |
910 | ||
00d4fce6 MK |
911 | if (debug_lin_lwp && num_events > 1) |
912 | fprintf_unfiltered (gdb_stdlog, | |
913 | "Found %d SIGTRAP events, selecting #%d\n", | |
914 | num_events, random_selector); | |
b1aeb4c5 | 915 | |
00d4fce6 MK |
916 | event_lp = iterate_over_lwps (select_event_lwp_callback, |
917 | &random_selector); | |
b1aeb4c5 MS |
918 | } |
919 | ||
920 | if (event_lp != NULL) | |
921 | { | |
00d4fce6 | 922 | /* Switch the event LWP. */ |
b1aeb4c5 MS |
923 | *orig_lp = event_lp; |
924 | *status = event_lp->status; | |
b1aeb4c5 | 925 | } |
00d4fce6 MK |
926 | |
927 | /* Flush the wait status for the event LWP. */ | |
928 | (*orig_lp)->status = 0; | |
b1aeb4c5 MS |
929 | } |
930 | ||
fce0e6e1 MK |
931 | /* Return non-zero if LP has been resumed. */ |
932 | ||
933 | static int | |
934 | resumed_callback (struct lwp_info *lp, void *data) | |
935 | { | |
936 | return lp->resumed; | |
937 | } | |
938 | ||
cacab7c4 MK |
939 | #ifdef CHILD_WAIT |
940 | ||
941 | /* We need to override child_wait to support attaching to cloned | |
942 | processes, since a normal wait (as done by the default version) | |
943 | ignores those processes. */ | |
944 | ||
945 | /* Wait for child PTID to do something. Return id of the child, | |
946 | minus_one_ptid in case of error; store status into *OURSTATUS. */ | |
947 | ||
948 | ptid_t | |
949 | child_wait (ptid_t ptid, struct target_waitstatus *ourstatus) | |
950 | { | |
951 | int save_errno; | |
952 | int status; | |
953 | pid_t pid; | |
954 | ||
955 | do | |
956 | { | |
957 | set_sigint_trap (); /* Causes SIGINT to be passed on to the | |
958 | attached process. */ | |
959 | set_sigio_trap (); | |
960 | ||
961 | pid = waitpid (GET_PID (ptid), &status, 0); | |
962 | if (pid == -1 && errno == ECHILD) | |
963 | /* Try again with __WCLONE to check cloned processes. */ | |
964 | pid = waitpid (GET_PID (ptid), &status, __WCLONE); | |
965 | save_errno = errno; | |
966 | ||
967 | clear_sigio_trap (); | |
968 | clear_sigint_trap (); | |
969 | } | |
2d1bfe2e | 970 | while (pid == -1 && save_errno == EINTR); |
cacab7c4 MK |
971 | |
972 | if (pid == -1) | |
973 | { | |
dc672865 | 974 | warning ("Child process unexpectedly missing: %s", safe_strerror (errno)); |
cacab7c4 MK |
975 | |
976 | /* Claim it exited with unknown signal. */ | |
977 | ourstatus->kind = TARGET_WAITKIND_SIGNALLED; | |
978 | ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN; | |
979 | return minus_one_ptid; | |
980 | } | |
981 | ||
982 | store_waitstatus (ourstatus, status); | |
983 | return pid_to_ptid (pid); | |
984 | } | |
985 | ||
986 | #endif | |
987 | ||
39f77062 KB |
988 | static ptid_t |
989 | lin_lwp_wait (ptid_t ptid, struct target_waitstatus *ourstatus) | |
fb0e1ba7 MK |
990 | { |
991 | struct lwp_info *lp = NULL; | |
992 | int options = 0; | |
993 | int status = 0; | |
39f77062 | 994 | pid_t pid = PIDGET (ptid); |
de4ca854 MK |
995 | sigset_t flush_mask; |
996 | ||
997 | sigemptyset (&flush_mask); | |
fb0e1ba7 | 998 | |
3f07c44b MK |
999 | /* Make sure SIGCHLD is blocked. */ |
1000 | if (! sigismember (&blocked_mask, SIGCHLD)) | |
1001 | { | |
1002 | sigaddset (&blocked_mask, SIGCHLD); | |
1003 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
1004 | } | |
1005 | ||
fb0e1ba7 MK |
1006 | retry: |
1007 | ||
9a973a8f MK |
1008 | /* Make sure there is at least one LWP that has been resumed, at |
1009 | least if there are any LWPs at all. */ | |
1010 | gdb_assert (num_lwps == 0 || iterate_over_lwps (resumed_callback, NULL)); | |
fce0e6e1 | 1011 | |
fb0e1ba7 MK |
1012 | /* First check if there is a LWP with a wait status pending. */ |
1013 | if (pid == -1) | |
1014 | { | |
b1aeb4c5 | 1015 | /* Any LWP that's been resumed will do. */ |
fb0e1ba7 MK |
1016 | lp = iterate_over_lwps (status_callback, NULL); |
1017 | if (lp) | |
1018 | { | |
fb0e1ba7 MK |
1019 | status = lp->status; |
1020 | lp->status = 0; | |
b1aeb4c5 MS |
1021 | |
1022 | if (debug_lin_lwp && status) | |
58eeadba MK |
1023 | fprintf_unfiltered (gdb_stdlog, |
1024 | "Using pending wait status %s for LWP %ld.\n", | |
1025 | status_to_str (status), GET_LWP (lp->ptid)); | |
fb0e1ba7 MK |
1026 | } |
1027 | ||
1028 | /* But if we don't fine one, we'll have to wait, and check both | |
1029 | cloned and uncloned processes. We start with the cloned | |
1030 | processes. */ | |
1031 | options = __WCLONE | WNOHANG; | |
1032 | } | |
39f77062 | 1033 | else if (is_lwp (ptid)) |
fb0e1ba7 | 1034 | { |
7ca673cd | 1035 | if (debug_lin_lwp) |
9085700c | 1036 | fprintf_unfiltered (gdb_stdlog, |
b08cfdb6 | 1037 | "Waiting for specific LWP %ld.\n", |
ce696e05 | 1038 | GET_LWP (ptid)); |
7ca673cd | 1039 | |
fb0e1ba7 | 1040 | /* We have a specific LWP to check. */ |
39f77062 | 1041 | lp = find_lwp_pid (ptid); |
fb0e1ba7 MK |
1042 | gdb_assert (lp); |
1043 | status = lp->status; | |
1044 | lp->status = 0; | |
7ca673cd | 1045 | |
b1aeb4c5 | 1046 | if (debug_lin_lwp && status) |
58eeadba MK |
1047 | fprintf_unfiltered (gdb_stdlog, |
1048 | "Using pending wait status %s for LWP %ld.\n", | |
1049 | status_to_str (status), GET_LWP (lp->ptid)); | |
fb0e1ba7 MK |
1050 | |
1051 | /* If we have to wait, take into account whether PID is a cloned | |
1052 | process or not. And we have to convert it to something that | |
1053 | the layer beneath us can understand. */ | |
cacab7c4 | 1054 | options = lp->cloned ? __WCLONE : 0; |
39f77062 | 1055 | pid = GET_LWP (ptid); |
fb0e1ba7 MK |
1056 | } |
1057 | ||
1058 | if (status && lp->signalled) | |
1059 | { | |
1060 | /* A pending SIGSTOP may interfere with the normal stream of | |
1061 | events. In a typical case where interference is a problem, | |
1062 | we have a SIGSTOP signal pending for LWP A while | |
1063 | single-stepping it, encounter an event in LWP B, and take the | |
1064 | pending SIGSTOP while trying to stop LWP A. After processing | |
1065 | the event in LWP B, LWP A is continued, and we'll never see | |
1066 | the SIGTRAP associated with the last time we were | |
1067 | single-stepping LWP A. */ | |
1068 | ||
1069 | /* Resume the thread. It should halt immediately returning the | |
1070 | pending SIGSTOP. */ | |
39f77062 KB |
1071 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, |
1072 | TARGET_SIGNAL_0); | |
fb0e1ba7 | 1073 | lp->stopped = 0; |
fce0e6e1 | 1074 | gdb_assert (lp->resumed); |
fb0e1ba7 MK |
1075 | |
1076 | /* This should catch the pending SIGSTOP. */ | |
1077 | stop_wait_callback (lp, NULL); | |
1078 | } | |
1079 | ||
1080 | set_sigint_trap (); /* Causes SIGINT to be passed on to the | |
1081 | attached process. */ | |
1082 | set_sigio_trap (); | |
1083 | ||
1084 | while (status == 0) | |
1085 | { | |
1086 | pid_t lwpid; | |
1087 | ||
1088 | lwpid = waitpid (pid, &status, options); | |
1089 | if (lwpid > 0) | |
1090 | { | |
1091 | gdb_assert (pid == -1 || lwpid == pid); | |
1092 | ||
39f77062 | 1093 | lp = find_lwp_pid (pid_to_ptid (lwpid)); |
fb0e1ba7 MK |
1094 | if (! lp) |
1095 | { | |
39f77062 | 1096 | lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid))); |
cacab7c4 MK |
1097 | if (options & __WCLONE) |
1098 | lp->cloned = 1; | |
1099 | ||
fb0e1ba7 MK |
1100 | if (threaded) |
1101 | { | |
3f07c44b MK |
1102 | gdb_assert (WIFSTOPPED (status) |
1103 | && WSTOPSIG (status) == SIGSTOP); | |
fb0e1ba7 MK |
1104 | lp->signalled = 1; |
1105 | ||
39f77062 | 1106 | if (! in_thread_list (inferior_ptid)) |
fb0e1ba7 | 1107 | { |
39f77062 KB |
1108 | inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid), |
1109 | GET_PID (inferior_ptid)); | |
1110 | add_thread (inferior_ptid); | |
fb0e1ba7 MK |
1111 | } |
1112 | ||
39f77062 | 1113 | add_thread (lp->ptid); |
fb0e1ba7 | 1114 | printf_unfiltered ("[New %s]\n", |
39f77062 | 1115 | target_pid_to_str (lp->ptid)); |
fb0e1ba7 MK |
1116 | } |
1117 | } | |
1118 | ||
1119 | /* Make sure we don't report a TARGET_WAITKIND_EXITED or | |
1120 | TARGET_WAITKIND_SIGNALLED event if there are still LWP's | |
1121 | left in the process. */ | |
1122 | if ((WIFEXITED (status) || WIFSIGNALED (status)) && num_lwps > 1) | |
1123 | { | |
39f77062 | 1124 | if (in_thread_list (lp->ptid)) |
fb0e1ba7 | 1125 | { |
e6328671 | 1126 | /* Core GDB cannot deal with us deleting the current |
fb0e1ba7 | 1127 | thread. */ |
39f77062 KB |
1128 | if (! ptid_equal (lp->ptid, inferior_ptid)) |
1129 | delete_thread (lp->ptid); | |
fb0e1ba7 | 1130 | printf_unfiltered ("[%s exited]\n", |
39f77062 | 1131 | target_pid_to_str (lp->ptid)); |
fb0e1ba7 | 1132 | } |
7ca673cd | 1133 | if (debug_lin_lwp) |
9085700c MS |
1134 | fprintf_unfiltered (gdb_stdlog, |
1135 | "%s exited.\n", | |
39f77062 | 1136 | target_pid_to_str (lp->ptid)); |
7ca673cd | 1137 | |
39f77062 | 1138 | delete_lwp (lp->ptid); |
fb0e1ba7 MK |
1139 | |
1140 | /* Make sure there is at least one thread running. */ | |
1141 | gdb_assert (iterate_over_lwps (running_callback, NULL)); | |
1142 | ||
1143 | /* Discard the event. */ | |
1144 | status = 0; | |
1145 | continue; | |
1146 | } | |
1147 | ||
1148 | /* Make sure we don't report a SIGSTOP that we sent | |
1149 | ourselves in an attempt to stop an LWP. */ | |
1150 | if (lp->signalled && WIFSTOPPED (status) | |
1151 | && WSTOPSIG (status) == SIGSTOP) | |
1152 | { | |
7ca673cd | 1153 | if (debug_lin_lwp) |
9085700c MS |
1154 | fprintf_unfiltered (gdb_stdlog, |
1155 | "Delayed SIGSTOP caught for %s.\n", | |
39f77062 | 1156 | target_pid_to_str (lp->ptid)); |
7ca673cd | 1157 | |
fb0e1ba7 MK |
1158 | /* This is a delayed SIGSTOP. */ |
1159 | lp->signalled = 0; | |
1160 | ||
39f77062 KB |
1161 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, |
1162 | TARGET_SIGNAL_0); | |
fb0e1ba7 | 1163 | lp->stopped = 0; |
fce0e6e1 | 1164 | gdb_assert (lp->resumed); |
fb0e1ba7 MK |
1165 | |
1166 | /* Discard the event. */ | |
1167 | status = 0; | |
1168 | continue; | |
1169 | } | |
1170 | ||
1171 | break; | |
1172 | } | |
1173 | ||
1174 | if (pid == -1) | |
1175 | { | |
1176 | /* Alternate between checking cloned and uncloned processes. */ | |
1177 | options ^= __WCLONE; | |
1178 | ||
1179 | /* And suspend every time we have checked both. */ | |
1180 | if (options & __WCLONE) | |
1181 | sigsuspend (&suspend_mask); | |
1182 | } | |
1183 | ||
1184 | /* We shouldn't end up here unless we want to try again. */ | |
1185 | gdb_assert (status == 0); | |
1186 | } | |
1187 | ||
1188 | clear_sigio_trap (); | |
1189 | clear_sigint_trap (); | |
1190 | ||
1191 | gdb_assert (lp); | |
1192 | ||
1193 | /* Don't report signals that GDB isn't interested in, such as | |
1194 | signals that are neither printed nor stopped upon. Stopping all | |
1195 | threads can be a bit time-consuming so if we want decent | |
1196 | performance with heavily multi-threaded programs, especially when | |
1197 | they're using a high frequency timer, we'd better avoid it if we | |
1198 | can. */ | |
1199 | ||
1200 | if (WIFSTOPPED (status)) | |
1201 | { | |
1202 | int signo = target_signal_from_host (WSTOPSIG (status)); | |
1203 | ||
1204 | if (signal_stop_state (signo) == 0 | |
1205 | && signal_print_state (signo) == 0 | |
1206 | && signal_pass_state (signo) == 1) | |
1207 | { | |
fce0e6e1 MK |
1208 | /* FIMXE: kettenis/2001-06-06: Should we resume all threads |
1209 | here? It is not clear we should. GDB may not expect | |
1210 | other threads to run. On the other hand, not resuming | |
1211 | newly attached threads may cause an unwanted delay in | |
1212 | getting them running. */ | |
c4365b19 | 1213 | child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, signo); |
fce0e6e1 | 1214 | lp->stopped = 0; |
fb0e1ba7 MK |
1215 | status = 0; |
1216 | goto retry; | |
1217 | } | |
de4ca854 MK |
1218 | |
1219 | if (signo == TARGET_SIGNAL_INT | |
1220 | && signal_pass_state (signo) == 0) | |
1221 | { | |
1222 | /* If ^C/BREAK is typed at the tty/console, SIGINT gets | |
1223 | forwarded to the entire process group, that is, all LWP's | |
1224 | will receive it. Since we only want to report it once, | |
1225 | we try to flush it from all LWPs except this one. */ | |
1226 | sigaddset (&flush_mask, SIGINT); | |
1227 | } | |
fb0e1ba7 MK |
1228 | } |
1229 | ||
1230 | /* This LWP is stopped now. */ | |
1231 | lp->stopped = 1; | |
1232 | ||
b1aeb4c5 | 1233 | if (debug_lin_lwp) |
58eeadba MK |
1234 | fprintf_unfiltered (gdb_stdlog, "Candidate event %s in LWP %ld.\n", |
1235 | status_to_str (status), GET_LWP (lp->ptid)); | |
b1aeb4c5 | 1236 | |
fb0e1ba7 MK |
1237 | /* Now stop all other LWP's ... */ |
1238 | iterate_over_lwps (stop_callback, NULL); | |
1239 | ||
1240 | /* ... and wait until all of them have reported back that they're no | |
1241 | longer running. */ | |
de4ca854 | 1242 | iterate_over_lwps (stop_wait_callback, &flush_mask); |
fb0e1ba7 | 1243 | |
00d4fce6 MK |
1244 | /* If we're not waiting for a specific LWP, choose an event LWP from |
1245 | among those that have had events. Giving equal priority to all | |
1246 | LWPs that have had events helps prevent starvation. */ | |
1247 | if (pid == -1) | |
1248 | select_event_lwp (&lp, &status); | |
b1aeb4c5 | 1249 | |
00d4fce6 MK |
1250 | /* Now that we've selected our final event LWP, cancel any |
1251 | breakpoints in other LWPs that have hit a GDB breakpoint. See | |
1252 | the comment in cancel_breakpoints_callback to find out why. */ | |
1253 | iterate_over_lwps (cancel_breakpoints_callback, lp); | |
b1aeb4c5 | 1254 | |
fb0e1ba7 MK |
1255 | /* If we're not running in "threaded" mode, we'll report the bare |
1256 | process id. */ | |
1257 | ||
1258 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP) | |
b1aeb4c5 MS |
1259 | { |
1260 | trap_ptid = (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid))); | |
1261 | if (debug_lin_lwp) | |
1262 | fprintf_unfiltered (gdb_stdlog, | |
1263 | "LLW: trap_ptid is %ld\n", | |
1264 | GET_LWP (trap_ptid)); | |
1265 | } | |
fb0e1ba7 | 1266 | else |
39f77062 | 1267 | trap_ptid = null_ptid; |
fb0e1ba7 MK |
1268 | |
1269 | store_waitstatus (ourstatus, status); | |
39f77062 | 1270 | return (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid))); |
fb0e1ba7 MK |
1271 | } |
1272 | ||
1273 | static int | |
1274 | kill_callback (struct lwp_info *lp, void *data) | |
1275 | { | |
39f77062 | 1276 | ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0); |
fb0e1ba7 MK |
1277 | return 0; |
1278 | } | |
1279 | ||
1280 | static int | |
1281 | kill_wait_callback (struct lwp_info *lp, void *data) | |
1282 | { | |
1283 | pid_t pid; | |
1284 | ||
1285 | /* We must make sure that there are no pending events (delayed | |
1286 | SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current | |
1287 | program doesn't interfere with any following debugging session. */ | |
1288 | ||
1289 | /* For cloned processes we must check both with __WCLONE and | |
1290 | without, since the exit status of a cloned process isn't reported | |
1291 | with __WCLONE. */ | |
cacab7c4 | 1292 | if (lp->cloned) |
fb0e1ba7 MK |
1293 | { |
1294 | do | |
1295 | { | |
39f77062 | 1296 | pid = waitpid (GET_LWP (lp->ptid), NULL, __WCLONE); |
fb0e1ba7 | 1297 | } |
39f77062 | 1298 | while (pid == GET_LWP (lp->ptid)); |
fb0e1ba7 MK |
1299 | |
1300 | gdb_assert (pid == -1 && errno == ECHILD); | |
1301 | } | |
1302 | ||
1303 | do | |
1304 | { | |
39f77062 | 1305 | pid = waitpid (GET_LWP (lp->ptid), NULL, 0); |
fb0e1ba7 | 1306 | } |
39f77062 | 1307 | while (pid == GET_LWP (lp->ptid)); |
fb0e1ba7 MK |
1308 | |
1309 | gdb_assert (pid == -1 && errno == ECHILD); | |
1310 | return 0; | |
1311 | } | |
1312 | ||
1313 | static void | |
1314 | lin_lwp_kill (void) | |
1315 | { | |
1316 | /* Kill all LWP's ... */ | |
1317 | iterate_over_lwps (kill_callback, NULL); | |
1318 | ||
1319 | /* ... and wait until we've flushed all events. */ | |
1320 | iterate_over_lwps (kill_wait_callback, NULL); | |
1321 | ||
1322 | target_mourn_inferior (); | |
1323 | } | |
1324 | ||
1325 | static void | |
1326 | lin_lwp_create_inferior (char *exec_file, char *allargs, char **env) | |
1327 | { | |
c194fbe1 | 1328 | child_ops.to_create_inferior (exec_file, allargs, env); |
fb0e1ba7 MK |
1329 | } |
1330 | ||
1331 | static void | |
1332 | lin_lwp_mourn_inferior (void) | |
1333 | { | |
c194fbe1 | 1334 | trap_ptid = null_ptid; |
fb0e1ba7 | 1335 | |
c194fbe1 | 1336 | /* Destroy LWP info; it's no longer valid. */ |
fb0e1ba7 MK |
1337 | init_lwp_list (); |
1338 | ||
4c8de859 | 1339 | /* Restore the original signal mask. */ |
3f07c44b MK |
1340 | sigprocmask (SIG_SETMASK, &normal_mask, NULL); |
1341 | sigemptyset (&blocked_mask); | |
1342 | ||
c194fbe1 | 1343 | child_ops.to_mourn_inferior (); |
fb0e1ba7 MK |
1344 | } |
1345 | ||
fb0e1ba7 MK |
1346 | static int |
1347 | lin_lwp_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write, | |
e5da8f38 | 1348 | struct mem_attrib *attrib, |
fb0e1ba7 MK |
1349 | struct target_ops *target) |
1350 | { | |
39f77062 | 1351 | struct cleanup *old_chain = save_inferior_ptid (); |
fb0e1ba7 MK |
1352 | int xfer; |
1353 | ||
39f77062 KB |
1354 | if (is_lwp (inferior_ptid)) |
1355 | inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid)); | |
fb0e1ba7 | 1356 | |
eb784848 DJ |
1357 | xfer = linux_proc_xfer_memory (memaddr, myaddr, len, write, attrib, target); |
1358 | if (xfer == 0) | |
1359 | xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target); | |
fb0e1ba7 MK |
1360 | |
1361 | do_cleanups (old_chain); | |
1362 | return xfer; | |
1363 | } | |
1364 | ||
1365 | static int | |
39f77062 | 1366 | lin_lwp_thread_alive (ptid_t ptid) |
fb0e1ba7 | 1367 | { |
39f77062 | 1368 | gdb_assert (is_lwp (ptid)); |
fb0e1ba7 MK |
1369 | |
1370 | errno = 0; | |
39f77062 | 1371 | ptrace (PTRACE_PEEKUSER, GET_LWP (ptid), 0, 0); |
fb0e1ba7 MK |
1372 | if (errno) |
1373 | return 0; | |
1374 | ||
1375 | return 1; | |
1376 | } | |
1377 | ||
1378 | static char * | |
39f77062 | 1379 | lin_lwp_pid_to_str (ptid_t ptid) |
fb0e1ba7 MK |
1380 | { |
1381 | static char buf[64]; | |
1382 | ||
39f77062 | 1383 | if (is_lwp (ptid)) |
fb0e1ba7 | 1384 | { |
b08cfdb6 | 1385 | snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid)); |
fb0e1ba7 MK |
1386 | return buf; |
1387 | } | |
1388 | ||
39f77062 | 1389 | return normal_pid_to_str (ptid); |
fb0e1ba7 MK |
1390 | } |
1391 | ||
1392 | static void | |
1393 | init_lin_lwp_ops (void) | |
1394 | { | |
1395 | #if 0 | |
1396 | lin_lwp_ops.to_open = lin_lwp_open; | |
1397 | #endif | |
1398 | lin_lwp_ops.to_shortname = "lwp-layer"; | |
1399 | lin_lwp_ops.to_longname = "lwp-layer"; | |
1400 | lin_lwp_ops.to_doc = "Low level threads support (LWP layer)"; | |
1401 | lin_lwp_ops.to_attach = lin_lwp_attach; | |
1402 | lin_lwp_ops.to_detach = lin_lwp_detach; | |
1403 | lin_lwp_ops.to_resume = lin_lwp_resume; | |
1404 | lin_lwp_ops.to_wait = lin_lwp_wait; | |
02ae7771 AC |
1405 | /* fetch_inferior_registers and store_inferior_registers will |
1406 | honor the LWP id, so we can use them directly. */ | |
1407 | lin_lwp_ops.to_fetch_registers = fetch_inferior_registers; | |
1408 | lin_lwp_ops.to_store_registers = store_inferior_registers; | |
fb0e1ba7 MK |
1409 | lin_lwp_ops.to_xfer_memory = lin_lwp_xfer_memory; |
1410 | lin_lwp_ops.to_kill = lin_lwp_kill; | |
1411 | lin_lwp_ops.to_create_inferior = lin_lwp_create_inferior; | |
1412 | lin_lwp_ops.to_mourn_inferior = lin_lwp_mourn_inferior; | |
1413 | lin_lwp_ops.to_thread_alive = lin_lwp_thread_alive; | |
1414 | lin_lwp_ops.to_pid_to_str = lin_lwp_pid_to_str; | |
1415 | lin_lwp_ops.to_stratum = thread_stratum; | |
1416 | lin_lwp_ops.to_has_thread_control = tc_schedlock; | |
1417 | lin_lwp_ops.to_magic = OPS_MAGIC; | |
1418 | } | |
1419 | ||
1420 | static void | |
1421 | sigchld_handler (int signo) | |
1422 | { | |
1423 | /* Do nothing. The only reason for this handler is that it allows | |
1424 | us to use sigsuspend in lin_lwp_wait above to wait for the | |
1425 | arrival of a SIGCHLD. */ | |
1426 | } | |
1427 | ||
1428 | void | |
1429 | _initialize_lin_lwp (void) | |
1430 | { | |
1431 | struct sigaction action; | |
fb0e1ba7 MK |
1432 | |
1433 | extern void thread_db_init (struct target_ops *); | |
1434 | ||
1435 | init_lin_lwp_ops (); | |
1436 | add_target (&lin_lwp_ops); | |
1437 | thread_db_init (&lin_lwp_ops); | |
1438 | ||
4c8de859 | 1439 | /* Save the original signal mask. */ |
3f07c44b MK |
1440 | sigprocmask (SIG_SETMASK, NULL, &normal_mask); |
1441 | ||
fb0e1ba7 MK |
1442 | action.sa_handler = sigchld_handler; |
1443 | sigemptyset (&action.sa_mask); | |
1444 | action.sa_flags = 0; | |
1445 | sigaction (SIGCHLD, &action, NULL); | |
1446 | ||
3f07c44b MK |
1447 | /* Make sure we don't block SIGCHLD during a sigsuspend. */ |
1448 | sigprocmask (SIG_SETMASK, NULL, &suspend_mask); | |
fb0e1ba7 | 1449 | sigdelset (&suspend_mask, SIGCHLD); |
3f07c44b MK |
1450 | |
1451 | sigemptyset (&blocked_mask); | |
7ca673cd MS |
1452 | |
1453 | add_show_from_set (add_set_cmd ("lin-lwp", no_class, var_zinteger, | |
1454 | (char *) &debug_lin_lwp, | |
8605d56e | 1455 | "Set debugging of GNU/Linux lwp module.\n\ |
7ca673cd MS |
1456 | Enables printf debugging output.\n", |
1457 | &setdebuglist), | |
1458 | &showdebuglist); | |
fb0e1ba7 MK |
1459 | } |
1460 | \f | |
1461 | ||
1462 | /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to | |
8605d56e AC |
1463 | the GNU/Linux Threads library and therefore doesn't really belong |
1464 | here. */ | |
fb0e1ba7 MK |
1465 | |
1466 | /* Read variable NAME in the target and return its value if found. | |
1467 | Otherwise return zero. It is assumed that the type of the variable | |
1468 | is `int'. */ | |
1469 | ||
1470 | static int | |
1471 | get_signo (const char *name) | |
1472 | { | |
1473 | struct minimal_symbol *ms; | |
1474 | int signo; | |
1475 | ||
1476 | ms = lookup_minimal_symbol (name, NULL, NULL); | |
1477 | if (ms == NULL) | |
1478 | return 0; | |
1479 | ||
1480 | if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (char *) &signo, | |
1481 | sizeof (signo)) != 0) | |
1482 | return 0; | |
1483 | ||
1484 | return signo; | |
1485 | } | |
1486 | ||
1487 | /* Return the set of signals used by the threads library in *SET. */ | |
1488 | ||
1489 | void | |
1490 | lin_thread_get_thread_signals (sigset_t *set) | |
1491 | { | |
3f07c44b MK |
1492 | struct sigaction action; |
1493 | int restart, cancel; | |
fb0e1ba7 MK |
1494 | |
1495 | sigemptyset (set); | |
1496 | ||
1497 | restart = get_signo ("__pthread_sig_restart"); | |
1498 | if (restart == 0) | |
1499 | return; | |
1500 | ||
1501 | cancel = get_signo ("__pthread_sig_cancel"); | |
1502 | if (cancel == 0) | |
1503 | return; | |
1504 | ||
1505 | sigaddset (set, restart); | |
1506 | sigaddset (set, cancel); | |
3f07c44b | 1507 | |
8605d56e AC |
1508 | /* The GNU/Linux Threads library makes terminating threads send a |
1509 | special "cancel" signal instead of SIGCHLD. Make sure we catch | |
1510 | those (to prevent them from terminating GDB itself, which is | |
1511 | likely to be their default action) and treat them the same way as | |
1512 | SIGCHLD. */ | |
3f07c44b MK |
1513 | |
1514 | action.sa_handler = sigchld_handler; | |
1515 | sigemptyset (&action.sa_mask); | |
1516 | action.sa_flags = 0; | |
1517 | sigaction (cancel, &action, NULL); | |
1518 | ||
1519 | /* We block the "cancel" signal throughout this code ... */ | |
1520 | sigaddset (&blocked_mask, cancel); | |
1521 | sigprocmask (SIG_BLOCK, &blocked_mask, NULL); | |
1522 | ||
1523 | /* ... except during a sigsuspend. */ | |
1524 | sigdelset (&suspend_mask, cancel); | |
fb0e1ba7 | 1525 | } |