1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
/* This testcase is part of GDB, the GNU debugger.
Copyright 2016-2020 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <sys/wait.h>
int fds[2] = { -1, -1 };
static void
grandparent_done (void)
{
}
/* The exp file overrides this in order to test both fork and
vfork. */
#ifndef FORK
#define FORK fork
#endif
int
main (void)
{
int pid;
int nbytes;
const char string[] = "Hello, world!\n";
char readbuffer[80];
/* Don't run forever. */
alarm (300);
/* Create a pipe. The write side will be inherited all the way to
the grandchild. The grandparent will read this, expecting to see
EOF (meaning the grandchild closed the pipe). */
pipe (fds);
pid = FORK ();
if (pid < 0)
{
perror ("fork");
exit (1);
}
else if (pid == 0)
{
/* Close input side of pipe. */
close (fds[0]);
pid = FORK ();
if (pid == 0)
{
printf ("I'm the grandchild!\n");
/* Don't explicitly close the pipe. If GDB fails to kill
this process, then the grandparent will hang in the pipe
read below. */
#if 0
close (fds[1]);
#endif
while (1)
sleep (1);
}
else
{
close (fds[1]);
printf ("I'm the proud parent of child #%d!\n", pid);
wait (NULL);
}
}
else if (pid > 0)
{
close (fds[1]);
printf ("I'm the proud parent of child #%d!\n", pid);
nbytes = read (fds[0], readbuffer, sizeof (readbuffer));
assert (nbytes == 0);
printf ("read returned nbytes=%d\n", nbytes);
wait (NULL);
grandparent_done ();
}
return 0;
}
|
