| /* This testcase is part of GDB, the GNU debugger. |
| |
| Copyright 2009-2017 Free Software Foundation, Inc. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #define _GNU_SOURCE |
| #include <pthread.h> |
| #include <stdio.h> |
| #include <limits.h> |
| #include <errno.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <assert.h> |
| #include <sys/types.h> |
| #include <signal.h> |
| #include <unistd.h> |
| #include <asm/unistd.h> |
| |
| #define gettid() syscall (__NR_gettid) |
| |
| /* Terminate always in the main task, it can lock up with SIGSTOPped GDB |
| otherwise. */ |
| #define TIMEOUT (gettid () == getpid() ? 10 : 15) |
| |
| static pid_t thread1_tid; |
| static pthread_cond_t thread1_tid_cond = PTHREAD_COND_INITIALIZER; |
| static pthread_mutex_t thread1_tid_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; |
| |
| static pid_t thread2_tid; |
| static pthread_cond_t thread2_tid_cond = PTHREAD_COND_INITIALIZER; |
| static pthread_mutex_t thread2_tid_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; |
| |
| static pthread_mutex_t terminate_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; |
| |
| static pthread_barrier_t threads_started_barrier; |
| |
| /* These variables must have lower in-memory addresses than thread1_rwatch and |
| thread2_rwatch so that they take their watchpoint slots. */ |
| |
| static int unused1_rwatch; |
| static int unused2_rwatch; |
| |
| static volatile int thread1_rwatch; |
| static volatile int thread2_rwatch; |
| |
| /* Do not use alarm as it would create a ptrace event which would hang up us if |
| we are being traced by GDB which we stopped ourselves. */ |
| |
| static void timed_mutex_lock (pthread_mutex_t *mutex) |
| { |
| int i; |
| struct timespec start, now; |
| |
| i = clock_gettime (CLOCK_MONOTONIC, &start); |
| assert (i == 0); |
| |
| do |
| { |
| i = pthread_mutex_trylock (mutex); |
| if (i == 0) |
| return; |
| assert (i == EBUSY); |
| |
| i = clock_gettime (CLOCK_MONOTONIC, &now); |
| assert (i == 0); |
| assert (now.tv_sec >= start.tv_sec); |
| } |
| while (now.tv_sec - start.tv_sec < TIMEOUT); |
| |
| fprintf (stderr, "Timed out waiting for internal lock!\n"); |
| exit (EXIT_FAILURE); |
| } |
| |
| static void * |
| thread1_func (void *unused) |
| { |
| int i; |
| volatile int rwatch_store; |
| |
| pthread_barrier_wait (&threads_started_barrier); |
| |
| timed_mutex_lock (&thread1_tid_mutex); |
| |
| /* THREAD1_TID_MUTEX must be already locked to avoid race. */ |
| thread1_tid = gettid (); |
| |
| i = pthread_cond_signal (&thread1_tid_cond); |
| assert (i == 0); |
| i = pthread_mutex_unlock (&thread1_tid_mutex); |
| assert (i == 0); |
| |
| rwatch_store = thread1_rwatch; |
| |
| /* Be sure the "t (tracing stop)" test can proceed for both threads. */ |
| timed_mutex_lock (&terminate_mutex); |
| i = pthread_mutex_unlock (&terminate_mutex); |
| assert (i == 0); |
| |
| return NULL; |
| } |
| |
| static void * |
| thread2_func (void *unused) |
| { |
| int i; |
| volatile int rwatch_store; |
| |
| pthread_barrier_wait (&threads_started_barrier); |
| |
| timed_mutex_lock (&thread2_tid_mutex); |
| |
| /* THREAD2_TID_MUTEX must be already locked to avoid race. */ |
| thread2_tid = gettid (); |
| |
| i = pthread_cond_signal (&thread2_tid_cond); |
| assert (i == 0); |
| i = pthread_mutex_unlock (&thread2_tid_mutex); |
| assert (i == 0); |
| |
| rwatch_store = thread2_rwatch; |
| |
| /* Be sure the "t (tracing stop)" test can proceed for both threads. */ |
| timed_mutex_lock (&terminate_mutex); |
| i = pthread_mutex_unlock (&terminate_mutex); |
| assert (i == 0); |
| |
| return NULL; |
| } |
| |
| static const char * |
| proc_string (const char *filename, const char *line) |
| { |
| FILE *f; |
| static char buf[LINE_MAX]; |
| size_t line_len = strlen (line); |
| |
| f = fopen (filename, "r"); |
| if (f == NULL) |
| { |
| fprintf (stderr, "fopen (\"%s\") for \"%s\": %s\n", filename, line, |
| strerror (errno)); |
| exit (EXIT_FAILURE); |
| } |
| while (errno = 0, fgets (buf, sizeof (buf), f)) |
| { |
| char *s; |
| |
| s = strchr (buf, '\n'); |
| assert (s != NULL); |
| *s = 0; |
| |
| if (strncmp (buf, line, line_len) != 0) |
| continue; |
| |
| if (fclose (f)) |
| { |
| fprintf (stderr, "fclose (\"%s\") for \"%s\": %s\n", filename, line, |
| strerror (errno)); |
| exit (EXIT_FAILURE); |
| } |
| |
| return &buf[line_len]; |
| } |
| if (errno != 0) |
| { |
| fprintf (stderr, "fgets (\"%s\": %s\n", filename, strerror (errno)); |
| exit (EXIT_FAILURE); |
| } |
| fprintf (stderr, "\"%s\": No line \"%s\" found.\n", filename, line); |
| exit (EXIT_FAILURE); |
| } |
| |
| static unsigned long |
| proc_ulong (const char *filename, const char *line) |
| { |
| const char *s = proc_string (filename, line); |
| long retval; |
| char *end; |
| |
| errno = 0; |
| retval = strtol (s, &end, 10); |
| if (retval < 0 || retval >= LONG_MAX || (end && *end)) |
| { |
| fprintf (stderr, "\"%s\":\"%s\": %ld, %s\n", filename, line, retval, |
| strerror (errno)); |
| exit (EXIT_FAILURE); |
| } |
| return retval; |
| } |
| |
| static void |
| state_wait (pid_t process, const char *wanted) |
| { |
| char *filename; |
| int i; |
| struct timespec start, now; |
| const char *state; |
| |
| i = asprintf (&filename, "/proc/%lu/status", (unsigned long) process); |
| assert (i > 0); |
| |
| i = clock_gettime (CLOCK_MONOTONIC, &start); |
| assert (i == 0); |
| |
| do |
| { |
| state = proc_string (filename, "State:\t"); |
| |
| /* torvalds/linux-2.6.git 464763cf1c6df632dccc8f2f4c7e50163154a2c0 |
| has changed "T (tracing stop)" to "t (tracing stop)". Make the GDB |
| testcase backward compatible with older Linux kernels. */ |
| if (strcmp (state, "T (tracing stop)") == 0) |
| state = "t (tracing stop)"; |
| |
| if (strcmp (state, wanted) == 0) |
| { |
| free (filename); |
| return; |
| } |
| |
| if (sched_yield ()) |
| { |
| perror ("sched_yield()"); |
| exit (EXIT_FAILURE); |
| } |
| |
| i = clock_gettime (CLOCK_MONOTONIC, &now); |
| assert (i == 0); |
| assert (now.tv_sec >= start.tv_sec); |
| } |
| while (now.tv_sec - start.tv_sec < TIMEOUT); |
| |
| fprintf (stderr, "Timed out waiting for PID %lu \"%s\" (now it is \"%s\")!\n", |
| (unsigned long) process, wanted, state); |
| exit (EXIT_FAILURE); |
| } |
| |
| static volatile pid_t tracer = 0; |
| static pthread_t thread1, thread2; |
| |
| static void |
| cleanup (void) |
| { |
| printf ("Resuming GDB PID %lu.\n", (unsigned long) tracer); |
| |
| if (tracer) |
| { |
| int i; |
| int tracer_save = tracer; |
| |
| tracer = 0; |
| |
| i = kill (tracer_save, SIGCONT); |
| assert (i == 0); |
| } |
| } |
| |
| int |
| main (int argc, char **argv) |
| { |
| int i; |
| int standalone = 0; |
| |
| if (argc == 2 && strcmp (argv[1], "-s") == 0) |
| standalone = 1; |
| else |
| assert (argc == 1); |
| |
| setbuf (stdout, NULL); |
| |
| timed_mutex_lock (&thread1_tid_mutex); |
| timed_mutex_lock (&thread2_tid_mutex); |
| |
| timed_mutex_lock (&terminate_mutex); |
| |
| pthread_barrier_init (&threads_started_barrier, NULL, 3); |
| |
| i = pthread_create (&thread1, NULL, thread1_func, NULL); |
| assert (i == 0); |
| |
| i = pthread_create (&thread2, NULL, thread2_func, NULL); |
| assert (i == 0); |
| |
| if (!standalone) |
| { |
| tracer = proc_ulong ("/proc/self/status", "TracerPid:\t"); |
| if (tracer == 0) |
| { |
| fprintf (stderr, "The testcase must be run by GDB!\n"); |
| exit (EXIT_FAILURE); |
| } |
| if (tracer != getppid ()) |
| { |
| fprintf (stderr, "The testcase parent must be our GDB tracer!\n"); |
| exit (EXIT_FAILURE); |
| } |
| } |
| |
| /* SIGCONT our debugger in the case of our crash as we would deadlock |
| otherwise. */ |
| |
| atexit (cleanup); |
| |
| /* Wait until all threads are seen running. On Linux (at least), |
| new threads start stopped, and the debugger must resume them. |
| Need to wait for that before stopping GDB. */ |
| pthread_barrier_wait (&threads_started_barrier); |
| |
| printf ("Stopping GDB PID %lu.\n", (unsigned long) tracer); |
| |
| if (tracer) |
| { |
| i = kill (tracer, SIGSTOP); |
| assert (i == 0); |
| state_wait (tracer, "T (stopped)"); |
| } |
| |
| /* Threads are now waiting at timed_mutex_lock (thread1_tid_mutex) and so |
| they could not trigger the watchpoints before GDB gets unstopped later. |
| Threads get resumed at pthread_cond_wait below. Use `while' loops for |
| protection against spurious pthread_cond_wait wakeups. */ |
| |
| printf ("Waiting till the threads initialize their TIDs.\n"); |
| |
| while (thread1_tid == 0) |
| { |
| i = pthread_cond_wait (&thread1_tid_cond, &thread1_tid_mutex); |
| assert (i == 0); |
| } |
| |
| while (thread2_tid == 0) |
| { |
| i = pthread_cond_wait (&thread2_tid_cond, &thread2_tid_mutex); |
| assert (i == 0); |
| } |
| |
| printf ("Thread 1 TID = %lu, thread 2 TID = %lu, PID = %lu.\n", |
| (unsigned long) thread1_tid, (unsigned long) thread2_tid, |
| (unsigned long) getpid ()); |
| |
| printf ("Waiting till the threads get trapped by the watchpoints.\n"); |
| |
| if (tracer) |
| { |
| /* s390x-unknown-linux-gnu will fail with "R (running)". */ |
| |
| state_wait (thread1_tid, "t (tracing stop)"); |
| |
| state_wait (thread2_tid, "t (tracing stop)"); |
| } |
| |
| cleanup (); |
| |
| printf ("Joining the threads.\n"); |
| |
| i = pthread_mutex_unlock (&terminate_mutex); |
| assert (i == 0); |
| |
| i = pthread_join (thread1, NULL); |
| assert (i == 0); |
| |
| i = pthread_join (thread2, NULL); |
| assert (i == 0); |
| |
| printf ("Exiting.\n"); /* break-at-exit */ |
| |
| /* Just prevent compiler `warning: unusedX_rwatch defined but not used'. */ |
| unused1_rwatch = 1; |
| unused2_rwatch = 2; |
| |
| return EXIT_SUCCESS; |
| } |