1/* Check posix_spawn add file actions.
2 Copyright (C) 2016-2024 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#include <intprops.h>
31
32#include <support/check.h>
33#include <support/temp_file.h>
34#include <support/xunistd.h>
35#include <tst-spawn.h>
36
37static int
38do_test (void)
39{
40 /* The test checks if posix_spawn open file action close the file descriptor
41 before opening a new one in case the input file descriptor is already
42 opened. It does by exhausting all file descriptors on the process before
43 issue posix_spawn. It then issues a posix_spawn for '/bin/sh echo $$'
44 and add two rules:
45
46 1. Redirect stdout to a temporary filepath
47 2. Redirect stderr to stdout
48
49 If the implementation does not close the file 1. will fail with
50 EMFILE. */
51
52 struct rlimit rl;
53 int max_fd = 24;
54
55 /* Set maximum number of file descriptor to a low value to avoid open
56 too many files in environments where RLIMIT_NOFILE is large and to
57 limit the array size to track the opened file descriptors. */
58
59 if (getrlimit (RLIMIT_NOFILE, rlimits: &rl) == -1)
60 FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
61
62 max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd);
63 rl.rlim_cur = max_fd;
64
65 if (setrlimit (RLIMIT_NOFILE, rlimits: &rl) == 1)
66 FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
67
68 /* Exhauste the file descriptor limit with temporary files. */
69 int files[max_fd];
70 int nfiles = 0;
71 for (; nfiles < max_fd; nfiles++)
72 {
73 int fd = create_temp_file (base: "tst-spawn3.", NULL);
74 if (fd == -1)
75 {
76 if (errno != EMFILE)
77 FAIL_EXIT1 ("create_temp_file: %m");
78 break;
79 }
80 files[nfiles] = fd;
81 }
82 TEST_VERIFY_EXIT (nfiles != 0);
83
84 posix_spawn_file_actions_t a;
85 TEST_COMPARE (posix_spawn_file_actions_init (&a), 0);
86
87 /* Executes a /bin/sh echo $$ 2>&1 > ${objpfx}tst-spawn3.pid . */
88 const char pidfile[] = OBJPFX "tst-spawn3.pid";
89 TEST_COMPARE (posix_spawn_file_actions_addopen (&a, STDOUT_FILENO, pidfile,
90 O_WRONLY| O_CREAT | O_TRUNC,
91 0644),
92 0);
93
94 TEST_COMPARE (posix_spawn_file_actions_adddup2 (&a, STDOUT_FILENO,
95 STDERR_FILENO),
96 0);
97
98 /* Since execve (called by posix_spawn) might require to open files to
99 actually execute the shell script, setup to close the temporary file
100 descriptors. */
101 int maxnfiles =
102#ifdef TST_SPAWN_PIDFD
103 /* The sparing file descriptor will be returned as the pid descriptor,
104 otherwise clone fail with EMFILE. */
105 nfiles - 1;
106#else
107 nfiles;
108#endif
109
110 for (int i=0; i<maxnfiles; i++)
111 TEST_COMPARE (posix_spawn_file_actions_addclose (&a, files[i]), 0);
112
113 char *spawn_argv[] = { (char *) _PATH_BSHELL, (char *) "-c",
114 (char *) "echo $$", NULL };
115 PID_T_TYPE pid;
116
117 {
118 int r = POSIX_SPAWN (&pid, _PATH_BSHELL, &a, NULL, spawn_argv, NULL);
119 if (r == ENOSYS)
120 FAIL_UNSUPPORTED ("kernel does not support CLONE_PIDFD clone flag");
121#ifdef TST_SPAWN_PIDFD
122 TEST_COMPARE (r, EMFILE);
123
124 /* Free up one file descriptor, so posix_spawn_pidfd_ex can return it. */
125 xclose (files[nfiles-1]);
126 nfiles--;
127 r = POSIX_SPAWN (&pid, _PATH_BSHELL, &a, NULL, spawn_argv, NULL);
128#endif
129 TEST_COMPARE (r, 0);
130 }
131
132 siginfo_t sinfo;
133 TEST_COMPARE (WAITID (P_PID, pid, &sinfo, WEXITED), 0);
134 TEST_COMPARE (sinfo.si_code, CLD_EXITED);
135 TEST_COMPARE (sinfo.si_status, 0);
136
137 /* Close the temporary files descriptor so it can check posix_spawn
138 output. */
139 for (int i=0; i<nfiles; i++)
140 xclose (files[i]);
141
142 int pidfd = xopen (path: pidfile, O_RDONLY, 0);
143
144 char buf[INT_BUFSIZE_BOUND (pid_t)];
145 ssize_t n = read (pidfd, buf, sizeof (buf));
146 TEST_VERIFY (n < sizeof buf && n >= 0);
147
148 xunlink (path: pidfile);
149
150 /* We only expect to read the PID. */
151 char *endp;
152 long int rpid = strtol (buf, &endp, 10);
153 TEST_VERIFY (*endp == '\n' && endp != buf);
154
155 TEST_COMPARE (rpid, sinfo.si_pid);
156
157 return 0;
158}
159
160#include <support/test-driver.c>
161

source code of glibc/posix/tst-spawn3.c