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

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2015-2022 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   return NULL;
  95 }
  96
  97 /* Set this to tell the thread_breakpoint thread to exit.  */
  98 volatile int break_out;
  99
 100 static void *
 101 thread_breakpoint (void *arg)
 102 {
 103   pthread_barrier_wait (&barrier);
 104
 105   while (!break_out)
 106     {
 107       usleep (1); /* set break here */
 108     }
 109
 110   return NULL;
 111 }
 112
 113 pthread_barrier_t barrier;
 114
 115 int
 116 main (void)
 117 {
 118   int i;
 119   int ret;
 120   pthread_t bp_thread;
 121
 122   /* Don't run forever.  */
 123   alarm (180);
 124
 125   pthread_barrier_init (&barrier, NULL, NTHREADS + 1);
 126
 127   /* Start the threads that constantly fork.  */
 128   for (i = 0; i < NTHREADS; i++)
 129     {
 130       ret = pthread_create (&threads[i], NULL, thread_forks, NULL);
 131       assert (ret == 0);
 132     }
 133
 134   /* Start the thread that constantly hit a conditional breakpoint
 135      that needs to be stepped over.  */
 136   ret = pthread_create (&bp_thread, NULL, thread_breakpoint, NULL);
 137   assert (ret == 0);
 138
 139   /* Wait for forking to stop.  */
 140   for (i = 0; i < NTHREADS; i++)
 141     {
 142       ret = pthread_join (threads[i], NULL);
 143       assert (ret == 0);
 144     }
 145
 146   break_out = 1;
 147   pthread_join (bp_thread, NULL);
 148   assert (ret == 0);
 149
 150   return 0;
 151 }