fork-plus-threads.c revision 1.1.1.4 
1/* This testcase is part of GDB, the GNU debugger.
2
3   Copyright 2015-2019 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 <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
25
26/* Number of times the main process forks.  */
27#define NFORKS 10
28
29/* Number of threads by each fork child.  */
30#define NTHREADS 10
31
32static void *
33thread_func (void *arg)
34{
35  /* Empty.  */
36}
37
38static void
39fork_child (void)
40{
41  pthread_t threads[NTHREADS];
42  int i;
43  int ret;
44
45  for (i = 0; i < NTHREADS; i++)
46    {
47      ret = pthread_create (&threads[i], NULL, thread_func, NULL);
48      assert (ret == 0);
49    }
50
51  for (i = 0; i < NTHREADS; i++)
52    {
53      ret = pthread_join (threads[i], NULL);
54      assert (ret == 0);
55    }
56}
57
58int
59main (void)
60{
61  pid_t childs[NFORKS];
62  int i;
63  int status;
64  int num_exited = 0;
65
66  /* Don't run forever if the wait loop below gets stuck.  */
67  alarm (180);
68
69  for (i = 0; i < NFORKS; i++)
70    {
71      pid_t pid;
72
73      pid = fork ();
74
75      if (pid > 0)
76	{
77	  /* Parent.  */
78	  childs[i] = pid;
79	}
80      else if (pid == 0)
81	{
82	  /* Child.  */
83	  fork_child ();
84	  return 0;
85	}
86      else
87	{
88	  perror ("fork");
89	  return 1;
90	}
91    }
92
93  while (num_exited != NFORKS)
94    {
95      pid_t pid = wait (&status);
96
97      if (pid == -1)
98	{
99	  perror ("wait");
100	  return 1;
101	}
102
103      if (WIFEXITED (status))
104	{
105	  num_exited++;
106	}
107      else
108	{
109	  printf ("Hmm, unexpected wait status 0x%x from child %d\n", status,
110		  pid);
111	}
112    }
113
114  return 0;
115}
116