1 /* $OpenBSD: nohup.c,v 1.18 2018/09/14 18:17:46 bluhm Exp $ */
2 /* $NetBSD: nohup.c,v 1.6 1995/08/31 23:35:25 jtc Exp $ */
3
4 /*
5 * Copyright (c) 1989 The Regents of the University of California.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/stat.h>
34 #include <fcntl.h>
35 #include <unistd.h>
36 #include <signal.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <errno.h>
41 #include <limits.h>
42 #include <err.h>
43
44 static void dofile(void);
45 __dead static void usage(void);
46
47 /*
48 * nohup shall exit with one of the following values:
49 * 126 - The utility was found but could not be invoked.
50 * 127 - An error occurred in the nohup utility, or the utility could
51 * not be found.
52 */
53 #define EXIT_NOEXEC 126
54 #define EXIT_NOTFOUND 127
55 #define EXIT_MISC 127
56
57 /*
58 * If the standard output is a terminal, all output written to
59 * its standard output shall be appended to the end of the file
60 * nohup.out in the current directory. If nohup.out cannot be
61 * created or opened for appending, the output shall be appended
62 * to the end of the file nohup.out in the directory specified
63 * by the HOME environment variable.
64 *
65 * If a file is created, the file's permission bits shall be
66 * set to S_IRUSR | S_IWUSR.
67 */
68 #define FILENAME "nohup.out"
69
70 int
main(int argc,char * argv[])71 main(int argc, char *argv[])
72 {
73 int exit_status;
74
75 if (pledge("stdio rpath wpath cpath exec", NULL) == -1)
76 err(1, "pledge");
77
78 if (argc < 2)
79 usage();
80
81 if (isatty(STDOUT_FILENO) || errno == EBADF)
82 dofile();
83
84 if (pledge("stdio exec", NULL) == -1)
85 err(1, "pledge");
86
87 if ((isatty(STDERR_FILENO) || errno == EBADF) &&
88 dup2(STDOUT_FILENO, STDERR_FILENO) == -1) {
89 /* may have just closed stderr */
90 (void)fprintf(stdin, "nohup: %s\n", strerror(errno));
91 exit(EXIT_MISC);
92 }
93
94 /*
95 * The nohup utility shall take the standard action for all signals
96 * except that SIGHUP shall be ignored.
97 */
98 (void)signal(SIGHUP, SIG_IGN);
99
100 execvp(argv[1], &argv[1]);
101 exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
102 err(exit_status, "%s", argv[1]);
103 }
104
105 static void
dofile(void)106 dofile(void)
107 {
108 int fd;
109 const char *p;
110 char path[PATH_MAX];
111
112 p = FILENAME;
113 if ((fd = open(p, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
114 goto dupit;
115 if ((p = getenv("HOME")) != NULL && *p != '\0' &&
116 (strlen(p) + strlen(FILENAME) + 1) < sizeof(path)) {
117 (void)strlcpy(path, p, sizeof(path));
118 (void)strlcat(path, "/", sizeof(path));
119 (void)strlcat(path, FILENAME, sizeof(path));
120 if ((fd = open(p = path, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
121 goto dupit;
122 }
123 errx(EXIT_MISC, "can't open a nohup.out file");
124
125 dupit:
126 (void)lseek(fd, (off_t)0, SEEK_END);
127 if (dup2(fd, STDOUT_FILENO) == -1)
128 err(EXIT_MISC, NULL);
129 if (fd > STDERR_FILENO)
130 (void)close(fd);
131 (void)fprintf(stderr, "sending output to %s\n", p);
132 }
133
134 __dead static void
usage(void)135 usage(void)
136 {
137 (void)fprintf(stderr, "usage: nohup utility [arg ...]\n");
138 exit(EXIT_MISC);
139 }
140