1 /*
2 * Copyright (c) International Business Machines Corp., 2001
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 *
18 *
19 * NAME
20 * fork12.c
21 *
22 * DESCRIPTION
23 * Check that all children inherit parent's file descriptor
24 *
25 * ALGORITHM
26 * Parent forks processes until -1 is returned.$
27 *
28 * USAGE
29 * fork12
30 * ** CAUTION ** Can hang your machine, esp prior to 2.4.19
31 *
32 * HISTORY
33 * 07/2001 Ported by Wayne Boyer
34 * 07/2002 Split from fork07 as a test case to exhaust available pids.
35 *
36 * RESTRICTIONS
37 * Should be run as root to avoid resource limits.$
38 * Should not be run with other test programs because it tries to
39 * use all available pids.
40 */
41
42 #include <stdio.h>
43 #include <sys/wait.h>
44 #include <errno.h>
45 #include <string.h>
46 #include "test.h"
47 #include "safe_macros.h"
48
49 char *TCID = "fork12";
50 int TST_TOTAL = 1;
51
52 static void setup(void);
53 static void cleanup(void);
54 static void fork12_sigs(int signum);
55
main(int ac,char ** av)56 int main(int ac, char **av)
57 {
58 int forks, pid1, fork_errno, waitstatus;
59 int ret, status;
60 int lc;
61
62 tst_parse_opts(ac, av, NULL, NULL);
63
64 setup();
65
66 for (lc = 0; TEST_LOOPING(lc); lc++) {
67 tst_count = 0;
68
69 tst_resm(TINFO, "Forking as many kids as possible");
70 forks = 0;
71 while ((pid1 = fork()) != -1) {
72 if (pid1 == 0) { /* child */
73 /*
74 * Taunt the OOM killer so that it doesn't
75 * kill system processes
76 */
77 SAFE_FILE_PRINTF(NULL,
78 "/proc/self/oom_score_adj", "500");
79 pause();
80 exit(0);
81 }
82 forks++;
83 ret = SAFE_WAITPID(cleanup, -1, &status, WNOHANG);
84 if (ret > 0) {
85 /* a child may be killed by OOM killer */
86 if (WTERMSIG(status) == SIGKILL)
87 break;
88 tst_brkm(TBROK, cleanup,
89 "child exit with error code %d or signal %d",
90 WEXITSTATUS(status), WTERMSIG(status));
91 }
92 }
93 fork_errno = errno;
94
95 /* parent */
96 tst_resm(TINFO, "Number of processes forked is %d", forks);
97 tst_resm(TPASS, "fork() eventually failed with %d: %s",
98 fork_errno, strerror(fork_errno));
99 /* collect our kids */
100 /*
101 * Introducing a sleep(3) to make sure all children are
102 * at pause() when SIGQUIT is sent to them
103 */
104 sleep(3);
105 kill(0, SIGQUIT);
106 while (wait(&waitstatus) > 0) ;
107
108 }
109
110 cleanup();
111 tst_exit();
112 }
113
setup(void)114 static void setup(void)
115 {
116 tst_sig(FORK, fork12_sigs, cleanup);
117 TEST_PAUSE;
118 }
119
cleanup(void)120 static void cleanup(void)
121 {
122 int waitstatus;
123
124 /* collect our kids */
125 kill(0, SIGQUIT);
126 while (wait(&waitstatus) > 0) ;
127 }
128
fork12_sigs(int signum)129 static void fork12_sigs(int signum)
130 {
131 if (signum == SIGQUIT) {
132 /* Children will continue, parent will ignore */
133 } else {
134 tst_brkm(TBROK, cleanup,
135 "Unexpected signal %d received.", signum);
136 }
137 }
138