1/* This testcase is part of GDB, the GNU debugger.
2
3   Copyright 2016-2020 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 <stdio.h>
19#include <stdlib.h>
20#include <unistd.h>
21#include <assert.h>
22#include <sys/wait.h>
23
24int fds[2] = { -1, -1 };
25
26static void
27grandparent_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
37int
38main (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}
99