1 /* Check posix_spawn add file actions.
2 Copyright (C) 2016-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <stdio.h>
20 #include <spawn.h>
21 #include <error.h>
22 #include <errno.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <unistd.h>
26 #include <sys/wait.h>
27 #include <sys/resource.h>
28 #include <fcntl.h>
29 #include <paths.h>
30
31 #include <support/check.h>
32 #include <support/temp_file.h>
33
34 static int
35 do_test (void)
36 {
37 /* The test checks if posix_spawn open file action close the file descriptor
38 before opening a new one in case the input file descriptor is already
39 opened. It does by exhausting all file descriptors on the process before
40 issue posix_spawn. It then issues a posix_spawn for '/bin/sh echo $$'
41 and add two rules:
42
43 1. Redirect stdout to a temporary filepath
44 2. Redirect stderr to stdout
45
46 If the implementation does not close the file 1. will fail with
47 EMFILE. */
48
49 struct rlimit rl;
50 int max_fd = 24;
51 int ret;
52
53 /* Set maximum number of file descriptor to a low value to avoid open
54 too many files in environments where RLIMIT_NOFILE is large and to
55 limit the array size to track the opened file descriptors. */
56
57 if (getrlimit (RLIMIT_NOFILE, &rl) == -1)
58 FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
59
60 max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd);
61 rl.rlim_cur = max_fd;
62
63 if (setrlimit (RLIMIT_NOFILE, &rl) == 1)
64 FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
65
66 /* Exhauste the file descriptor limit with temporary files. */
67 int files[max_fd];
68 int nfiles = 0;
69 for (;;)
70 {
71 int fd = create_temp_file ("tst-spawn3.", NULL);
72 if (fd == -1)
73 {
74 if (errno != EMFILE)
75 FAIL_EXIT1 ("create_temp_file: %m");
76 break;
77 }
78 files[nfiles++] = fd;
79 }
80
81 posix_spawn_file_actions_t a;
82 if (posix_spawn_file_actions_init (&a) != 0)
83 FAIL_EXIT1 ("posix_spawn_file_actions_init");
84
85 /* Executes a /bin/sh echo $$ 2>&1 > ${objpfx}tst-spawn3.pid . */
86 const char pidfile[] = OBJPFX "tst-spawn3.pid";
87 if (posix_spawn_file_actions_addopen (&a, STDOUT_FILENO, pidfile, O_WRONLY
88 | O_CREAT | O_TRUNC, 0644) != 0)
89 FAIL_EXIT1 ("posix_spawn_file_actions_addopen");
90
91 if (posix_spawn_file_actions_adddup2 (&a, STDOUT_FILENO, STDERR_FILENO) != 0)
92 FAIL_EXIT1 ("posix_spawn_file_actions_adddup2");
93
94 /* Since execve (called by posix_spawn) might require to open files to
95 actually execute the shell script, setup to close the temporary file
96 descriptors. */
97 for (int i=0; i<nfiles; i++)
98 {
99 if (posix_spawn_file_actions_addclose (&a, files[i]))
100 FAIL_EXIT1 ("posix_spawn_file_actions_addclose");
101 }
102
103 char *spawn_argv[] = { (char *) _PATH_BSHELL, (char *) "-c",
104 (char *) "echo $$", NULL };
105 pid_t pid;
106 if ((ret = posix_spawn (&pid, _PATH_BSHELL, &a, NULL, spawn_argv, NULL))
107 != 0)
108 {
109 errno = ret;
110 FAIL_EXIT1 ("posix_spawn: %m");
111 }
112
113 int status;
114 int err = waitpid (pid, &status, 0);
115 if (err != pid)
116 FAIL_EXIT1 ("waitpid: %m");
117
118 /* Close the temporary files descriptor so it can check posix_spawn
119 output. */
120 for (int i=0; i<nfiles; i++)
121 {
122 if (close (files[i]))
123 FAIL_EXIT1 ("close: %m");
124 }
125
126 int pidfd = open (pidfile, O_RDONLY);
127 if (pidfd == -1)
128 FAIL_EXIT1 ("open: %m");
129
130 char buf[64];
131 ssize_t n;
132 if ((n = read (pidfd, buf, sizeof (buf))) < 0)
133 FAIL_EXIT1 ("read: %m");
134
135 unlink (pidfile);
136
137 /* We only expect to read the PID. */
138 char *endp;
139 long int rpid = strtol (buf, &endp, 10);
140 if (*endp != '\n')
141 FAIL_EXIT1 ("*endp != \'n\'");
142 if (endp == buf)
143 FAIL_EXIT1 ("read empty line");
144
145 if (rpid != pid)
146 FAIL_EXIT1 ("found \"%s\", expected pid %ld\n", buf, (long int) pid);
147
148 return 0;
149 }
150
151 #include <support/test-driver.c>