1/*	$NetBSD: nohup.c,v 1.14 2009/04/12 23:38:17 lukem Exp $	*/
2
3/*
4 * Copyright (c) 1989 The Regents of the University of California.
5 * 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#include <sys/cdefs.h>
33#ifndef lint
34__COPYRIGHT("@(#) Copyright (c) 1989\
35 The Regents of the University of California.  All rights reserved.");
36#endif /* not lint */
37
38#ifndef lint
39#if 0
40static char sccsid[] = "@(#)nohup.c	5.4 (Berkeley) 6/1/90";
41#endif
42__RCSID("$NetBSD: nohup.c,v 1.14 2009/04/12 23:38:17 lukem Exp $");
43#endif /* not lint */
44
45#include <sys/param.h>
46#include <sys/file.h>
47#include <sys/stat.h>
48#include <fcntl.h>
49#include <unistd.h>
50#include <signal.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include <string.h>
54#include <errno.h>
55
56static void dofile(void);
57__dead static void usage(void);
58
59/* nohup shall exit with one of the following values:
60   126 - The utility was found but could not be invoked.
61   127 - An error occurred in the nohup utility, or the utility could
62         not be found. */
63#define EXIT_NOEXEC	126
64#define EXIT_NOTFOUND	127
65#define EXIT_MISC	127
66
67int
68main(int argc, char **argv)
69{
70	int exit_status;
71
72	while (getopt(argc, argv, "") != -1) {
73		usage();
74	}
75	argc -= optind;
76	argv += optind;
77
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		(void)fprintf(stdin, "nohup: %s\n", strerror(errno));
86		exit(EXIT_MISC);
87	}
88
89	/* The nohup utility shall take the standard action for all signals
90	   except that SIGHUP shall be ignored. */
91	(void)signal(SIGHUP, SIG_IGN);
92
93	execvp(argv[0], &argv[0]);
94	exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
95	(void)fprintf(stderr, "nohup: %s: %s\n", argv[0], strerror(errno));
96	exit(exit_status);
97}
98
99static void
100dofile(void)
101{
102	int fd;
103	char path[MAXPATHLEN];
104	const char *p;
105
106	/* If the standard output is a terminal, all output written to
107	   its standard output shall be appended to the end of the file
108	   nohup.out in the current directory.  If nohup.out cannot be
109	   created or opened for appending, the output shall be appended
110	   to the end of the file nohup.out in the directory specified
111	   by the HOME environment variable.
112
113	   If a file is created, the file's permission bits shall be
114	   set to S_IRUSR | S_IWUSR. */
115#define	FILENAME	"nohup.out"
116	p = FILENAME;
117	if ((fd = open(p, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
118		goto dupit;
119	if ((p = getenv("HOME")) != NULL) {
120		(void)strlcpy(path, p, sizeof(path));
121		(void)strlcat(path, "/", sizeof(path));
122		(void)strlcat(path, FILENAME, sizeof(path));
123		if ((fd = open(p = path, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
124			goto dupit;
125	}
126	(void)fprintf(stderr, "nohup: can't open a nohup.out file.\n");
127	exit(EXIT_MISC);
128
129dupit:	(void)lseek(fd, 0L, SEEK_END);
130	if (dup2(fd, STDOUT_FILENO) == -1) {
131		(void)fprintf(stderr, "nohup: %s\n", strerror(errno));
132		exit(EXIT_MISC);
133	}
134	(void)fprintf(stderr, "sending output to %s\n", p);
135}
136
137static void
138usage(void)
139{
140	(void)fprintf(stderr, "usage: nohup utility [argument ...]\n");
141	exit(EXIT_MISC);
142}
143