1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #if 0
33 #ifndef lint
34 static const char copyright[] =
35 "@(#) Copyright (c) 1989, 1993\n\
36 The Regents of the University of California. All rights reserved.\n";
37 #endif /* not lint */
38
39 #ifndef lint
40 static char sccsid[] = "@(#)nohup.c 8.1 (Berkeley) 6/6/93";
41 #endif /* not lint */
42 #endif
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD: stable/12/usr.bin/nohup/nohup.c 326025 2017-11-20 19:49:47Z pfg $");
45
46 #include <sys/param.h>
47 #include <sys/stat.h>
48
49 #include <err.h>
50 #include <errno.h>
51 #include <fcntl.h>
52 #include <signal.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <unistd.h>
57
58 static void dofile(void);
59 static void usage(void);
60
61 #define FILENAME "nohup.out"
62 /*
63 * POSIX mandates that we exit with:
64 * 126 - If the utility was found, but failed to execute.
65 * 127 - If any other error occurred.
66 */
67 #define EXIT_NOEXEC 126
68 #define EXIT_NOTFOUND 127
69 #define EXIT_MISC 127
70
71 int
main(int argc,char * argv[])72 main(int argc, char *argv[])
73 {
74 int exit_status;
75
76 while (getopt(argc, argv, "") != -1)
77 usage();
78 argc -= optind;
79 argv += optind;
80 if (argc < 1)
81 usage();
82
83 if (isatty(STDOUT_FILENO))
84 dofile();
85 if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1)
86 /* may have just closed stderr */
87 err(EXIT_MISC, "%s", argv[0]);
88
89 (void)signal(SIGHUP, SIG_IGN);
90
91 execvp(*argv, argv);
92 exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
93 err(exit_status, "%s", argv[0]);
94 }
95
96 static void
dofile(void)97 dofile(void)
98 {
99 int fd;
100 char path[MAXPATHLEN];
101 const char *p;
102
103 /*
104 * POSIX mandates if the standard output is a terminal, the standard
105 * output is appended to nohup.out in the working directory. Failing
106 * that, it will be appended to nohup.out in the directory obtained
107 * from the HOME environment variable. If file creation is required,
108 * the mode_t is set to S_IRUSR | S_IWUSR.
109 */
110 p = FILENAME;
111 fd = open(p, O_RDWR | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR);
112 if (fd != -1)
113 goto dupit;
114 if ((p = getenv("HOME")) != NULL && *p != '\0' &&
115 (size_t)snprintf(path, sizeof(path), "%s/%s", p, FILENAME) <
116 sizeof(path)) {
117 fd = open(p = path, O_RDWR | O_CREAT | O_APPEND,
118 S_IRUSR | S_IWUSR);
119 if (fd != -1)
120 goto dupit;
121 }
122 errx(EXIT_MISC, "can't open a nohup.out file");
123
124 dupit:
125 if (dup2(fd, STDOUT_FILENO) == -1)
126 err(EXIT_MISC, NULL);
127 (void)fprintf(stderr, "appending output to %s\n", p);
128 }
129
130 static void
usage(void)131 usage(void)
132 {
133 (void)fprintf(stderr, "usage: nohup [--] utility [arguments]\n");
134 exit(EXIT_MISC);
135 }
136