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26ab7092 JK |
1 | /* This testcase is part of GDB, the GNU debugger. |
2 | ||
8acc9f48 | 3 | Copyright 2010-2013 Free Software Foundation, Inc. |
26ab7092 JK |
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 | ||
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 | /* Do not use alarm as it would create a ptrace event which would hang up us if | |
48 | we are being traced by GDB which we stopped ourselves. */ | |
49 | ||
50 | static void timed_mutex_lock (pthread_mutex_t *mutex) | |
51 | { | |
52 | int i; | |
53 | struct timespec start, now; | |
54 | ||
55 | i = clock_gettime (CLOCK_MONOTONIC, &start); | |
56 | assert (i == 0); | |
57 | ||
58 | do | |
59 | { | |
60 | i = pthread_mutex_trylock (mutex); | |
61 | if (i == 0) | |
62 | return; | |
63 | assert (i == EBUSY); | |
64 | ||
65 | i = clock_gettime (CLOCK_MONOTONIC, &now); | |
66 | assert (i == 0); | |
67 | assert (now.tv_sec >= start.tv_sec); | |
68 | } | |
69 | while (now.tv_sec - start.tv_sec < TIMEOUT); | |
70 | ||
71 | fprintf (stderr, "Timed out waiting for internal lock!\n"); | |
72 | exit (EXIT_FAILURE); | |
73 | } | |
74 | ||
75 | static void * | |
76 | thread_func (void *threadno_voidp) | |
77 | { | |
78 | int threadno = (intptr_t) threadno_voidp; | |
79 | int i; | |
80 | ||
81 | switch (threadno) | |
82 | { | |
83 | case 1: | |
84 | timed_mutex_lock (&thread1_tid_mutex); | |
85 | ||
86 | /* THREAD1_TID_MUTEX must be already locked to avoid race. */ | |
87 | thread1_tid = gettid (); | |
88 | ||
89 | i = pthread_cond_signal (&thread1_tid_cond); | |
90 | assert (i == 0); | |
91 | i = pthread_mutex_unlock (&thread1_tid_mutex); | |
92 | assert (i == 0); | |
93 | ||
94 | break; | |
95 | ||
96 | case 2: | |
97 | timed_mutex_lock (&thread2_tid_mutex); | |
98 | ||
99 | /* THREAD2_TID_MUTEX must be already locked to avoid race. */ | |
100 | thread2_tid = gettid (); | |
101 | ||
102 | i = pthread_cond_signal (&thread2_tid_cond); | |
103 | assert (i == 0); | |
104 | i = pthread_mutex_unlock (&thread2_tid_mutex); | |
105 | assert (i == 0); | |
106 | ||
107 | break; | |
108 | ||
109 | default: | |
110 | assert (0); | |
111 | } | |
112 | ||
113 | #ifdef __ia64__ | |
114 | asm volatile ("label:\n" | |
115 | "nop.m 0\n" | |
116 | "nop.i 0\n" | |
117 | "nop.b 0\n"); | |
118 | #endif | |
119 | /* break-here */ | |
120 | ||
121 | /* Be sure the "t (tracing stop)" test can proceed for both threads. */ | |
122 | timed_mutex_lock (&terminate_mutex); | |
123 | i = pthread_mutex_unlock (&terminate_mutex); | |
124 | assert (i == 0); | |
125 | ||
126 | return NULL; | |
127 | } | |
128 | ||
129 | static const char * | |
130 | proc_string (const char *filename, const char *line) | |
131 | { | |
132 | FILE *f; | |
133 | static char buf[LINE_MAX]; | |
134 | size_t line_len = strlen (line); | |
135 | ||
136 | f = fopen (filename, "r"); | |
137 | if (f == NULL) | |
138 | { | |
139 | fprintf (stderr, "fopen (\"%s\") for \"%s\": %s\n", filename, line, | |
140 | strerror (errno)); | |
141 | exit (EXIT_FAILURE); | |
142 | } | |
143 | while (errno = 0, fgets (buf, sizeof (buf), f)) | |
144 | { | |
145 | char *s; | |
146 | ||
147 | s = strchr (buf, '\n'); | |
148 | assert (s != NULL); | |
149 | *s = 0; | |
150 | ||
151 | if (strncmp (buf, line, line_len) != 0) | |
152 | continue; | |
153 | ||
154 | if (fclose (f)) | |
155 | { | |
156 | fprintf (stderr, "fclose (\"%s\") for \"%s\": %s\n", filename, line, | |
157 | strerror (errno)); | |
158 | exit (EXIT_FAILURE); | |
159 | } | |
160 | ||
161 | return &buf[line_len]; | |
162 | } | |
163 | if (errno != 0) | |
164 | { | |
165 | fprintf (stderr, "fgets (\"%s\": %s\n", filename, strerror (errno)); | |
166 | exit (EXIT_FAILURE); | |
167 | } | |
168 | fprintf (stderr, "\"%s\": No line \"%s\" found.\n", filename, line); | |
169 | exit (EXIT_FAILURE); | |
170 | } | |
171 | ||
172 | static unsigned long | |
173 | proc_ulong (const char *filename, const char *line) | |
174 | { | |
175 | const char *s = proc_string (filename, line); | |
176 | long retval; | |
177 | char *end; | |
178 | ||
179 | errno = 0; | |
180 | retval = strtol (s, &end, 10); | |
181 | if (retval < 0 || retval >= LONG_MAX || (end && *end)) | |
182 | { | |
183 | fprintf (stderr, "\"%s\":\"%s\": %ld, %s\n", filename, line, retval, | |
184 | strerror (errno)); | |
185 | exit (EXIT_FAILURE); | |
186 | } | |
187 | return retval; | |
188 | } | |
189 | ||
190 | static void | |
191 | state_wait (pid_t process, const char *wanted) | |
192 | { | |
193 | char *filename; | |
194 | int i; | |
195 | struct timespec start, now; | |
196 | const char *state; | |
197 | ||
198 | i = asprintf (&filename, "/proc/%lu/status", (unsigned long) process); | |
199 | assert (i > 0); | |
200 | ||
201 | i = clock_gettime (CLOCK_MONOTONIC, &start); | |
202 | assert (i == 0); | |
203 | ||
204 | do | |
205 | { | |
206 | state = proc_string (filename, "State:\t"); | |
207 | ||
208 | /* torvalds/linux-2.6.git 464763cf1c6df632dccc8f2f4c7e50163154a2c0 | |
209 | has changed "T (tracing stop)" to "t (tracing stop)". Make the GDB | |
210 | testcase backward compatible with older Linux kernels. */ | |
211 | if (strcmp (state, "T (tracing stop)") == 0) | |
212 | state = "t (tracing stop)"; | |
213 | ||
214 | if (strcmp (state, wanted) == 0) | |
215 | { | |
216 | free (filename); | |
217 | return; | |
218 | } | |
219 | ||
220 | if (sched_yield ()) | |
221 | { | |
222 | perror ("sched_yield()"); | |
223 | exit (EXIT_FAILURE); | |
224 | } | |
225 | ||
226 | i = clock_gettime (CLOCK_MONOTONIC, &now); | |
227 | assert (i == 0); | |
228 | assert (now.tv_sec >= start.tv_sec); | |
229 | } | |
230 | while (now.tv_sec - start.tv_sec < TIMEOUT); | |
231 | ||
232 | fprintf (stderr, "Timed out waiting for PID %lu \"%s\" (now it is \"%s\")!\n", | |
233 | (unsigned long) process, wanted, state); | |
234 | exit (EXIT_FAILURE); | |
235 | } | |
236 | ||
237 | static volatile pid_t tracer = 0; | |
238 | static pthread_t thread1, thread2; | |
239 | ||
240 | static void | |
241 | cleanup (void) | |
242 | { | |
243 | printf ("Resuming GDB PID %lu.\n", (unsigned long) tracer); | |
244 | ||
245 | if (tracer) | |
246 | { | |
247 | int i; | |
248 | int tracer_save = tracer; | |
249 | ||
250 | tracer = 0; | |
251 | ||
252 | i = kill (tracer_save, SIGCONT); | |
253 | assert (i == 0); | |
254 | } | |
255 | } | |
256 | ||
257 | int | |
258 | main (int argc, char **argv) | |
259 | { | |
260 | int i; | |
261 | int standalone = 0; | |
262 | ||
263 | if (argc == 2 && strcmp (argv[1], "-s") == 0) | |
264 | standalone = 1; | |
265 | else | |
266 | assert (argc == 1); | |
267 | ||
268 | setbuf (stdout, NULL); | |
269 | ||
270 | timed_mutex_lock (&thread1_tid_mutex); | |
271 | timed_mutex_lock (&thread2_tid_mutex); | |
272 | ||
273 | timed_mutex_lock (&terminate_mutex); | |
274 | ||
275 | i = pthread_create (&thread1, NULL, thread_func, (void *) (intptr_t) 1); | |
276 | assert (i == 0); | |
277 | ||
278 | i = pthread_create (&thread2, NULL, thread_func, (void *) (intptr_t) 2); | |
279 | assert (i == 0); | |
280 | ||
281 | if (!standalone) | |
282 | { | |
283 | tracer = proc_ulong ("/proc/self/status", "TracerPid:\t"); | |
284 | if (tracer == 0) | |
285 | { | |
286 | fprintf (stderr, "The testcase must be run by GDB!\n"); | |
287 | exit (EXIT_FAILURE); | |
288 | } | |
289 | if (tracer != getppid ()) | |
290 | { | |
291 | fprintf (stderr, "The testcase parent must be our GDB tracer!\n"); | |
292 | exit (EXIT_FAILURE); | |
293 | } | |
294 | } | |
295 | ||
296 | /* SIGCONT our debugger in the case of our crash as we would deadlock | |
297 | otherwise. */ | |
298 | ||
299 | atexit (cleanup); | |
300 | ||
301 | printf ("Stopping GDB PID %lu.\n", (unsigned long) tracer); | |
302 | ||
303 | if (tracer) | |
304 | { | |
305 | i = kill (tracer, SIGSTOP); | |
306 | assert (i == 0); | |
307 | state_wait (tracer, "T (stopped)"); | |
308 | } | |
309 | ||
310 | /* Threads are now waiting at timed_mutex_lock (thread1_tid_mutex) and so | |
311 | they could not trigger the breakpoint before GDB gets unstopped later. | |
312 | Threads get resumed at pthread_cond_wait below. Use `while' loops for | |
313 | protection against spurious pthread_cond_wait wakeups. */ | |
314 | ||
315 | printf ("Waiting till the threads initialize their TIDs.\n"); | |
316 | ||
317 | while (thread1_tid == 0) | |
318 | { | |
319 | i = pthread_cond_wait (&thread1_tid_cond, &thread1_tid_mutex); | |
320 | assert (i == 0); | |
321 | } | |
322 | ||
323 | while (thread2_tid == 0) | |
324 | { | |
325 | i = pthread_cond_wait (&thread2_tid_cond, &thread2_tid_mutex); | |
326 | assert (i == 0); | |
327 | } | |
328 | ||
329 | printf ("Thread 1 TID = %lu, thread 2 TID = %lu, PID = %lu.\n", | |
330 | (unsigned long) thread1_tid, (unsigned long) thread2_tid, | |
331 | (unsigned long) getpid ()); | |
332 | ||
333 | printf ("Waiting till the threads get trapped by the breakpoint.\n"); | |
334 | ||
335 | if (tracer) | |
336 | { | |
337 | /* s390x-unknown-linux-gnu will fail with "R (running)". */ | |
338 | ||
339 | state_wait (thread1_tid, "t (tracing stop)"); | |
340 | ||
341 | state_wait (thread2_tid, "t (tracing stop)"); | |
342 | } | |
343 | ||
344 | cleanup (); | |
345 | ||
346 | printf ("Joining the threads.\n"); | |
347 | ||
348 | i = pthread_mutex_unlock (&terminate_mutex); | |
349 | assert (i == 0); | |
350 | ||
351 | i = pthread_join (thread1, NULL); | |
352 | assert (i == 0); | |
353 | ||
354 | i = pthread_join (thread2, NULL); | |
355 | assert (i == 0); | |
356 | ||
357 | printf ("Exiting.\n"); /* break-at-exit */ | |
358 | ||
359 | return EXIT_SUCCESS; | |
360 | } |