gdb/testsuite/gdb.base/catch-fork-kill.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2016-2019 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 <stdio.h>
  19 #include <stdlib.h>
  20 #include <unistd.h>
  21 #include <assert.h>
  22 #include <sys/wait.h>
  23
  24 int fds[2] = { -1, -1 };
  25
  26 static void
  27 grandparent_done (void)
  28 {
  29 }
  30
  31 /* The exp file overrides this in order to test both fork and
  32    vfork.  */
  33 #ifndef FORK
  34 #define FORK fork
  35 #endif
  36
  37 int
  38 main (void)
  39 {
  40   int pid;
  41   int nbytes;
  42   const char string[] = "Hello, world!\n";
  43   char readbuffer[80];
  44
  45   /* Don't run forever.  */
  46   alarm (300);
  47
  48   /* Create a pipe.  The write side will be inherited all the way to
  49      the grandchild.  The grandparent will read this, expecting to see
  50      EOF (meaning the grandchild closed the pipe).  */
  51   pipe (fds);
  52
  53   pid = FORK ();
  54   if (pid < 0)
  55     {
  56       perror ("fork");
  57       exit (1);
  58     }
  59   else if (pid == 0)
  60     {
  61       /* Close input side of pipe.  */
  62       close (fds[0]);
  63
  64       pid = FORK ();
  65       if (pid == 0)
  66         {
  67           printf ("I'm the grandchild!\n");
  68
  69           /* Don't explicitly close the pipe.  If GDB fails to kill
  70              this process, then the grandparent will hang in the pipe
  71              read below.  */
  72 #if 0
  73           close (fds[1]);
  74 #endif
  75           while (1)
  76             sleep (1);
  77         }
  78       else
  79         {
  80           close (fds[1]);
  81           printf ("I'm the proud parent of child #%d!\n", pid);
  82           wait (NULL);
  83         }
  84     }
  85   else if (pid > 0)
  86     {
  87       close (fds[1]);
  88       printf ("I'm the proud parent of child #%d!\n", pid);
  89       nbytes = read (fds[0], readbuffer, sizeof (readbuffer));
  90       assert (nbytes == 0);
  91       printf ("read returned nbytes=%d\n", nbytes);
  92       wait (NULL);
  93
  94       grandparent_done ();
  95     }
  96
  97   return 0;
  98 }