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

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2015-2020 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 #include <errno.h>
  26
  27 /* Number of threads.  Each thread continuously spawns a fork and wait
  28    for it.  If we have another thread continuously start a step over,
  29    gdbserver should end up finding new forks while suspending
  30    threads.  */
  31 #define NTHREADS 10
  32
  33 pthread_t threads[NTHREADS];
  34
  35 pthread_barrier_t barrier;
  36
  37 #define NFORKS 10
  38
  39 /* Used to create a conditional breakpoint that always fails.  */
  40 volatile int zero;
  41
  42 static void *
  43 thread_forks (void *arg)
  44 {
  45   int i;
  46
  47   pthread_barrier_wait (&barrier);
  48
  49   for (i = 0; i < NFORKS; i++)
  50     {
  51       pid_t pid;
  52
  53       do
  54         {
  55           pid = fork ();
  56         }
  57       while (pid == -1 && errno == EINTR);
  58
  59       if (pid > 0)
  60         {
  61           int status;
  62
  63           /* Parent.  */
  64           do
  65             {
  66               pid = waitpid (pid, &status, 0);
  67             }
  68           while (pid == -1 && errno == EINTR);
  69
  70           if (pid == -1)
  71             {
  72               perror ("wait");
  73               exit (1);
  74             }
  75
  76           if (!WIFEXITED (status))
  77             {
  78               printf ("Unexpected wait status 0x%x from child %d\n",
  79                       status, pid);
  80             }
  81         }
  82       else if (pid == 0)
  83         {
  84           /* Child.  */
  85           exit (0);
  86         }
  87       else
  88         {
  89           perror ("fork");
  90           exit (1);
  91         }
  92     }
  93 }
  94
  95 /* Set this to tell the thread_breakpoint thread to exit.  */
  96 volatile int break_out;
  97
  98 static void *
  99 thread_breakpoint (void *arg)
 100 {
 101   pthread_barrier_wait (&barrier);
 102
 103   while (!break_out)
 104     {
 105       usleep (1); /* set break here */
 106     }
 107
 108   return NULL;
 109 }
 110
 111 pthread_barrier_t barrier;
 112
 113 int
 114 main (void)
 115 {
 116   int i;
 117   int ret;
 118   pthread_t bp_thread;
 119
 120   /* Don't run forever.  */
 121   alarm (180);
 122
 123   pthread_barrier_init (&barrier, NULL, NTHREADS + 1);
 124
 125   /* Start the threads that constantly fork.  */
 126   for (i = 0; i < NTHREADS; i++)
 127     {
 128       ret = pthread_create (&threads[i], NULL, thread_forks, NULL);
 129       assert (ret == 0);
 130     }
 131
 132   /* Start the thread that constantly hit a conditional breakpoint
 133      that needs to be stepped over.  */
 134   ret = pthread_create (&bp_thread, NULL, thread_breakpoint, NULL);
 135   assert (ret == 0);
 136
 137   /* Wait for forking to stop.  */
 138   for (i = 0; i < NTHREADS; i++)
 139     {
 140       ret = pthread_join (threads[i], NULL);
 141       assert (ret == 0);
 142     }
 143
 144   break_out = 1;
 145   pthread_join (bp_thread, NULL);
 146   assert (ret == 0);
 147
 148   return 0;
 149 }