gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2015-2016 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 #include <assert.h>
  19 #include <pthread.h>
  20 #include <unistd.h>
  21 #include <stdio.h>
  22 #include <sys/types.h>
  23 #include <sys/wait.h>
  24 #include <stdlib.h>
  25
  26 /* Number of threads.  Each thread continuously spawns a fork and wait
  27    for it.  If we have another thread continuously start a step over,
  28    gdbserver should end up finding new forks while suspending
  29    threads.  */
  30 #define NTHREADS 10
  31
  32 pthread_t threads[NTHREADS];
  33
  34 pthread_barrier_t barrier;
  35
  36 #define NFORKS 10
  37
  38 /* Used to create a conditional breakpoint that always fails.  */
  39 volatile int zero;
  40
  41 static void *
  42 thread_forks (void *arg)
  43 {
  44   int i;
  45
  46   pthread_barrier_wait (&barrier);
  47
  48   for (i = 0; i < NFORKS; i++)
  49     {
  50       pid_t pid;
  51
  52       pid = fork ();
  53
  54       if (pid > 0)
  55         {
  56           int status;
  57
  58           /* Parent.  */
  59           pid = waitpid (pid, &status, 0);
  60           if (pid == -1)
  61             {
  62               perror ("wait");
  63               exit (1);
  64             }
  65
  66           if (!WIFEXITED (status))
  67             {
  68               printf ("Unexpected wait status 0x%x from child %d\n",
  69                       status, pid);
  70             }
  71         }
  72       else if (pid == 0)
  73         {
  74           /* Child.  */
  75           exit (0);
  76         }
  77       else
  78         {
  79           perror ("fork");
  80           exit (1);
  81         }
  82     }
  83 }
  84
  85 /* Set this to tell the thread_breakpoint thread to exit.  */
  86 volatile int break_out;
  87
  88 static void *
  89 thread_breakpoint (void *arg)
  90 {
  91   pthread_barrier_wait (&barrier);
  92
  93   while (!break_out)
  94     {
  95       usleep (1); /* set break here */
  96     }
  97
  98   return NULL;
  99 }
 100
 101 pthread_barrier_t barrier;
 102
 103 int
 104 main (void)
 105 {
 106   int i;
 107   int ret;
 108   pthread_t bp_thread;
 109
 110   /* Don't run forever.  */
 111   alarm (180);
 112
 113   pthread_barrier_init (&barrier, NULL, NTHREADS + 1);
 114
 115   /* Start the threads that constantly fork.  */
 116   for (i = 0; i < NTHREADS; i++)
 117     {
 118       ret = pthread_create (&threads[i], NULL, thread_forks, NULL);
 119       assert (ret == 0);
 120     }
 121
 122   /* Start the thread that constantly hit a conditional breakpoint
 123      that needs to be stepped over.  */
 124   ret = pthread_create (&bp_thread, NULL, thread_breakpoint, NULL);
 125   assert (ret == 0);
 126
 127   /* Wait for forking to stop.  */
 128   for (i = 0; i < NTHREADS; i++)
 129     {
 130       ret = pthread_join (threads[i], NULL);
 131       assert (ret == 0);
 132     }
 133
 134   break_out = 1;
 135   pthread_join (bp_thread, NULL);
 136   assert (ret == 0);
 137
 138   return 0;
 139 }