gdb/testsuite/gdb.threads/watchpoint-fork-child.c

   1 /* Test case for forgotten hw-watchpoints after fork()-off of a process.
   2
   3    Copyright 2012-2023 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "watchpoint-fork.h"
  21
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <unistd.h>
  25 #include <assert.h>
  26 #include <signal.h>
  27 #include <stdio.h>
  28
  29 /* `pid_t' may not be available.  */
  30
  31 static volatile int usr1_got;
  32
  33 static void
  34 handler_usr1 (int signo)
  35 {
  36   usr1_got++;
  37 }
  38
  39 void
  40 forkoff (int nr)
  41 {
  42   int child, save_parent = getpid ();
  43   int i;
  44   struct sigaction act, oldact;
  45 #ifdef THREAD
  46   void *thread_result;
  47 #endif
  48
  49   memset (&act, 0, sizeof act);
  50   act.sa_flags = SA_RESTART;
  51   act.sa_handler = handler_usr1;
  52   sigemptyset (&act.sa_mask);
  53   i = sigaction (SIGUSR1, &act, &oldact);
  54   assert (i == 0);
  55
  56   child = fork ();
  57   switch (child)
  58     {
  59     case -1:
  60       assert (0);
  61     default:
  62 #if DEBUG
  63       printf ("parent%d: %d\n", nr, (int) child);
  64 #endif
  65
  66       /* Sleep for a while to possibly get incorrectly ATTACH_THREADed by GDB
  67          tracing the child fork with no longer valid thread/lwp entries of the
  68          parent.  */
  69
  70       i = sleep (2);
  71       assert (i == 0);
  72
  73       /* We must not get caught here (against a forgotten breakpoint).  */
  74
  75       var++;
  76       marker ();
  77
  78 #ifdef THREAD
  79       /* And neither got caught our thread.  */
  80
  81       step = 99;
  82       i = pthread_join (thread, &thread_result);
  83       assert (i == 0);
  84       assert (thread_result == (void *) 99UL);
  85 #endif
  86
  87       /* Be sure our child knows we did not get caught above.  */
  88
  89       i = kill (child, SIGUSR1);
  90       assert (i == 0);
  91
  92       /* Sleep for a while to check GDB's `info threads' no longer tracks us in
  93          the child fork.  */
  94
  95       i = sleep (2);
  96       assert (i == 0);
  97
  98       _exit (0);
  99     case 0:
 100 #if DEBUG
 101       printf ("child%d: %d\n", nr, (int) getpid ());
 102 #endif
 103
 104       /* Let the parent signal us about its success.  Be careful of races.  */
 105
 106       for (;;)
 107         {
 108           /* Parent either died (and USR1_GOT is zero) or it succeeded.  */
 109           if (getppid () != save_parent)
 110             break;
 111           if (kill (getppid (), 0) != 0)
 112             break;
 113           /* Parent succeeded?  */
 114           if (usr1_got)
 115             break;
 116
 117 #ifdef THREAD
 118           i = pthread_yield ();
 119           assert (i == 0);
 120 #endif
 121         }
 122       assert (usr1_got);
 123
 124       /* We must get caught here (against a false watchpoint removal).  */
 125
 126       marker ();
 127     }
 128
 129   i = sigaction (SIGUSR1, &oldact, NULL);
 130   assert (i == 0);
 131 }