| 1 | /* This testcase is part of GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 2010 Free Software Foundation, Inc. |
| 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 | } |