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ebec9a0f PA |
1 | /* This testcase is part of GDB, the GNU debugger. |
2 | ||
ecd75fc8 | 3 | Copyright 2009-2014 Free Software Foundation, Inc. |
ebec9a0f PA |
4 | |
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #define _GNU_SOURCE | |
19 | #include <pthread.h> | |
20 | #include <stdio.h> | |
21 | #include <limits.h> | |
22 | #include <errno.h> | |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
25 | #include <assert.h> | |
26 | #include <sys/types.h> | |
27 | #include <signal.h> | |
28 | #include <unistd.h> | |
29 | #include <asm/unistd.h> | |
30 | ||
31 | #define gettid() syscall (__NR_gettid) | |
32 | ||
33 | /* Terminate always in the main task, it can lock up with SIGSTOPped GDB | |
34 | otherwise. */ | |
35 | #define TIMEOUT (gettid () == getpid() ? 10 : 15) | |
36 | ||
ebec9a0f PA |
37 | static pid_t thread1_tid; |
38 | static pthread_cond_t thread1_tid_cond = PTHREAD_COND_INITIALIZER; | |
39 | static pthread_mutex_t thread1_tid_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; | |
40 | ||
41 | static pid_t thread2_tid; | |
42 | static pthread_cond_t thread2_tid_cond = PTHREAD_COND_INITIALIZER; | |
43 | static pthread_mutex_t thread2_tid_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; | |
44 | ||
45 | static pthread_mutex_t terminate_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; | |
46 | ||
47 | /* These variables must have lower in-memory addresses than thread1_rwatch and | |
48 | thread2_rwatch so that they take their watchpoint slots. */ | |
49 | ||
50 | static int unused1_rwatch; | |
51 | static int unused2_rwatch; | |
52 | ||
53 | static volatile int thread1_rwatch; | |
54 | static volatile int thread2_rwatch; | |
55 | ||
56 | /* Do not use alarm as it would create a ptrace event which would hang up us if | |
57 | we are being traced by GDB which we stopped ourselves. */ | |
58 | ||
59 | static void timed_mutex_lock (pthread_mutex_t *mutex) | |
60 | { | |
61 | int i; | |
62 | struct timespec start, now; | |
63 | ||
64 | i = clock_gettime (CLOCK_MONOTONIC, &start); | |
65 | assert (i == 0); | |
66 | ||
67 | do | |
68 | { | |
69 | i = pthread_mutex_trylock (mutex); | |
70 | if (i == 0) | |
71 | return; | |
72 | assert (i == EBUSY); | |
73 | ||
74 | i = clock_gettime (CLOCK_MONOTONIC, &now); | |
75 | assert (i == 0); | |
76 | assert (now.tv_sec >= start.tv_sec); | |
77 | } | |
78 | while (now.tv_sec - start.tv_sec < TIMEOUT); | |
79 | ||
80 | fprintf (stderr, "Timed out waiting for internal lock!\n"); | |
81 | exit (EXIT_FAILURE); | |
82 | } | |
83 | ||
84 | static void * | |
85 | thread1_func (void *unused) | |
86 | { | |
87 | int i; | |
88 | volatile int rwatch_store; | |
89 | ||
23787403 JK |
90 | timed_mutex_lock (&thread1_tid_mutex); |
91 | ||
92 | /* THREAD1_TID_MUTEX must be already locked to avoid race. */ | |
ebec9a0f | 93 | thread1_tid = gettid (); |
23787403 | 94 | |
ebec9a0f PA |
95 | i = pthread_cond_signal (&thread1_tid_cond); |
96 | assert (i == 0); | |
23787403 | 97 | i = pthread_mutex_unlock (&thread1_tid_mutex); |
ebec9a0f PA |
98 | assert (i == 0); |
99 | ||
100 | rwatch_store = thread1_rwatch; | |
101 | ||
09eef106 | 102 | /* Be sure the "t (tracing stop)" test can proceed for both threads. */ |
ebec9a0f PA |
103 | timed_mutex_lock (&terminate_mutex); |
104 | i = pthread_mutex_unlock (&terminate_mutex); | |
105 | assert (i == 0); | |
106 | ||
107 | return NULL; | |
108 | } | |
109 | ||
110 | static void * | |
111 | thread2_func (void *unused) | |
112 | { | |
113 | int i; | |
114 | volatile int rwatch_store; | |
115 | ||
23787403 JK |
116 | timed_mutex_lock (&thread2_tid_mutex); |
117 | ||
118 | /* THREAD2_TID_MUTEX must be already locked to avoid race. */ | |
ebec9a0f | 119 | thread2_tid = gettid (); |
23787403 | 120 | |
ebec9a0f PA |
121 | i = pthread_cond_signal (&thread2_tid_cond); |
122 | assert (i == 0); | |
23787403 | 123 | i = pthread_mutex_unlock (&thread2_tid_mutex); |
ebec9a0f PA |
124 | assert (i == 0); |
125 | ||
126 | rwatch_store = thread2_rwatch; | |
127 | ||
09eef106 | 128 | /* Be sure the "t (tracing stop)" test can proceed for both threads. */ |
ebec9a0f PA |
129 | timed_mutex_lock (&terminate_mutex); |
130 | i = pthread_mutex_unlock (&terminate_mutex); | |
131 | assert (i == 0); | |
132 | ||
133 | return NULL; | |
134 | } | |
135 | ||
136 | static const char * | |
137 | proc_string (const char *filename, const char *line) | |
138 | { | |
139 | FILE *f; | |
140 | static char buf[LINE_MAX]; | |
141 | size_t line_len = strlen (line); | |
142 | ||
143 | f = fopen (filename, "r"); | |
144 | if (f == NULL) | |
145 | { | |
146 | fprintf (stderr, "fopen (\"%s\") for \"%s\": %s\n", filename, line, | |
147 | strerror (errno)); | |
148 | exit (EXIT_FAILURE); | |
149 | } | |
150 | while (errno = 0, fgets (buf, sizeof (buf), f)) | |
151 | { | |
152 | char *s; | |
153 | ||
154 | s = strchr (buf, '\n'); | |
155 | assert (s != NULL); | |
156 | *s = 0; | |
157 | ||
158 | if (strncmp (buf, line, line_len) != 0) | |
159 | continue; | |
160 | ||
161 | if (fclose (f)) | |
162 | { | |
163 | fprintf (stderr, "fclose (\"%s\") for \"%s\": %s\n", filename, line, | |
164 | strerror (errno)); | |
165 | exit (EXIT_FAILURE); | |
166 | } | |
167 | ||
168 | return &buf[line_len]; | |
169 | } | |
170 | if (errno != 0) | |
171 | { | |
172 | fprintf (stderr, "fgets (\"%s\": %s\n", filename, strerror (errno)); | |
173 | exit (EXIT_FAILURE); | |
174 | } | |
175 | fprintf (stderr, "\"%s\": No line \"%s\" found.\n", filename, line); | |
176 | exit (EXIT_FAILURE); | |
177 | } | |
178 | ||
179 | static unsigned long | |
180 | proc_ulong (const char *filename, const char *line) | |
181 | { | |
182 | const char *s = proc_string (filename, line); | |
183 | long retval; | |
184 | char *end; | |
185 | ||
186 | errno = 0; | |
187 | retval = strtol (s, &end, 10); | |
188 | if (retval < 0 || retval >= LONG_MAX || (end && *end)) | |
189 | { | |
190 | fprintf (stderr, "\"%s\":\"%s\": %ld, %s\n", filename, line, retval, | |
191 | strerror (errno)); | |
192 | exit (EXIT_FAILURE); | |
193 | } | |
194 | return retval; | |
195 | } | |
196 | ||
197 | static void | |
198 | state_wait (pid_t process, const char *wanted) | |
199 | { | |
200 | char *filename; | |
201 | int i; | |
202 | struct timespec start, now; | |
203 | const char *state; | |
204 | ||
205 | i = asprintf (&filename, "/proc/%lu/status", (unsigned long) process); | |
206 | assert (i > 0); | |
207 | ||
208 | i = clock_gettime (CLOCK_MONOTONIC, &start); | |
209 | assert (i == 0); | |
210 | ||
211 | do | |
212 | { | |
213 | state = proc_string (filename, "State:\t"); | |
09eef106 JK |
214 | |
215 | /* torvalds/linux-2.6.git 464763cf1c6df632dccc8f2f4c7e50163154a2c0 | |
216 | has changed "T (tracing stop)" to "t (tracing stop)". Make the GDB | |
217 | testcase backward compatible with older Linux kernels. */ | |
218 | if (strcmp (state, "T (tracing stop)") == 0) | |
219 | state = "t (tracing stop)"; | |
220 | ||
ebec9a0f PA |
221 | if (strcmp (state, wanted) == 0) |
222 | { | |
223 | free (filename); | |
224 | return; | |
225 | } | |
226 | ||
227 | if (sched_yield ()) | |
228 | { | |
229 | perror ("sched_yield()"); | |
230 | exit (EXIT_FAILURE); | |
231 | } | |
232 | ||
233 | i = clock_gettime (CLOCK_MONOTONIC, &now); | |
234 | assert (i == 0); | |
235 | assert (now.tv_sec >= start.tv_sec); | |
236 | } | |
237 | while (now.tv_sec - start.tv_sec < TIMEOUT); | |
238 | ||
239 | fprintf (stderr, "Timed out waiting for PID %lu \"%s\" (now it is \"%s\")!\n", | |
240 | (unsigned long) process, wanted, state); | |
241 | exit (EXIT_FAILURE); | |
242 | } | |
243 | ||
244 | static volatile pid_t tracer = 0; | |
245 | static pthread_t thread1, thread2; | |
246 | ||
247 | static void | |
248 | cleanup (void) | |
249 | { | |
250 | printf ("Resuming GDB PID %lu.\n", (unsigned long) tracer); | |
251 | ||
252 | if (tracer) | |
253 | { | |
254 | int i; | |
255 | int tracer_save = tracer; | |
256 | ||
257 | tracer = 0; | |
258 | ||
259 | i = kill (tracer_save, SIGCONT); | |
260 | assert (i == 0); | |
261 | } | |
262 | } | |
263 | ||
264 | int | |
265 | main (int argc, char **argv) | |
266 | { | |
267 | int i; | |
268 | int standalone = 0; | |
269 | ||
270 | if (argc == 2 && strcmp (argv[1], "-s") == 0) | |
271 | standalone = 1; | |
272 | else | |
273 | assert (argc == 1); | |
274 | ||
275 | setbuf (stdout, NULL); | |
276 | ||
23787403 JK |
277 | timed_mutex_lock (&thread1_tid_mutex); |
278 | timed_mutex_lock (&thread2_tid_mutex); | |
ebec9a0f PA |
279 | |
280 | timed_mutex_lock (&terminate_mutex); | |
281 | ||
282 | i = pthread_create (&thread1, NULL, thread1_func, NULL); | |
283 | assert (i == 0); | |
284 | ||
285 | i = pthread_create (&thread2, NULL, thread2_func, NULL); | |
286 | assert (i == 0); | |
287 | ||
288 | if (!standalone) | |
289 | { | |
290 | tracer = proc_ulong ("/proc/self/status", "TracerPid:\t"); | |
291 | if (tracer == 0) | |
292 | { | |
293 | fprintf (stderr, "The testcase must be run by GDB!\n"); | |
294 | exit (EXIT_FAILURE); | |
295 | } | |
296 | if (tracer != getppid ()) | |
297 | { | |
298 | fprintf (stderr, "The testcase parent must be our GDB tracer!\n"); | |
299 | exit (EXIT_FAILURE); | |
300 | } | |
301 | } | |
302 | ||
303 | /* SIGCONT our debugger in the case of our crash as we would deadlock | |
304 | otherwise. */ | |
305 | ||
306 | atexit (cleanup); | |
307 | ||
308 | printf ("Stopping GDB PID %lu.\n", (unsigned long) tracer); | |
309 | ||
310 | if (tracer) | |
311 | { | |
312 | i = kill (tracer, SIGSTOP); | |
313 | assert (i == 0); | |
314 | state_wait (tracer, "T (stopped)"); | |
315 | } | |
316 | ||
23787403 JK |
317 | /* Threads are now waiting at timed_mutex_lock (thread1_tid_mutex) and so |
318 | they could not trigger the watchpoints before GDB gets unstopped later. | |
319 | Threads get resumed at pthread_cond_wait below. Use `while' loops for | |
320 | protection against spurious pthread_cond_wait wakeups. */ | |
ebec9a0f PA |
321 | |
322 | printf ("Waiting till the threads initialize their TIDs.\n"); | |
323 | ||
23787403 | 324 | while (thread1_tid == 0) |
ebec9a0f PA |
325 | { |
326 | i = pthread_cond_wait (&thread1_tid_cond, &thread1_tid_mutex); | |
327 | assert (i == 0); | |
ebec9a0f PA |
328 | } |
329 | ||
23787403 | 330 | while (thread2_tid == 0) |
ebec9a0f PA |
331 | { |
332 | i = pthread_cond_wait (&thread2_tid_cond, &thread2_tid_mutex); | |
333 | assert (i == 0); | |
ebec9a0f PA |
334 | } |
335 | ||
336 | printf ("Thread 1 TID = %lu, thread 2 TID = %lu, PID = %lu.\n", | |
337 | (unsigned long) thread1_tid, (unsigned long) thread2_tid, | |
338 | (unsigned long) getpid ()); | |
339 | ||
340 | printf ("Waiting till the threads get trapped by the watchpoints.\n"); | |
341 | ||
342 | if (tracer) | |
343 | { | |
344 | /* s390x-unknown-linux-gnu will fail with "R (running)". */ | |
345 | ||
09eef106 | 346 | state_wait (thread1_tid, "t (tracing stop)"); |
ebec9a0f | 347 | |
09eef106 | 348 | state_wait (thread2_tid, "t (tracing stop)"); |
ebec9a0f PA |
349 | } |
350 | ||
351 | cleanup (); | |
352 | ||
353 | printf ("Joining the threads.\n"); | |
354 | ||
355 | i = pthread_mutex_unlock (&terminate_mutex); | |
356 | assert (i == 0); | |
357 | ||
358 | i = pthread_join (thread1, NULL); | |
359 | assert (i == 0); | |
360 | ||
361 | i = pthread_join (thread2, NULL); | |
362 | assert (i == 0); | |
363 | ||
364 | printf ("Exiting.\n"); /* break-at-exit */ | |
365 | ||
366 | /* Just prevent compiler `warning: unusedX_rwatch defined but not used'. */ | |
367 | unused1_rwatch = 1; | |
368 | unused2_rwatch = 2; | |
369 | ||
370 | return EXIT_SUCCESS; | |
371 | } |