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
34static 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
40static char sccsid[] = "@(#)nohup.c	8.1 (Berkeley) 6/6/93";
41#endif /* not lint */
42#endif
43#include <sys/cdefs.h>
44__FBSDID("$FreeBSD$");
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
58static void dofile(void);
59static 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
71int
72main(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
96static void
97dofile(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
124dupit:
125	if (dup2(fd, STDOUT_FILENO) == -1)
126		err(EXIT_MISC, NULL);
127	(void)fprintf(stderr, "appending output to %s\n", p);
128}
129
130static void
131usage(void)
132{
133	(void)fprintf(stderr, "usage: nohup [--] utility [arguments]\n");
134	exit(EXIT_MISC);
135}
136