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