nohup.c revision 50477 
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1989, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)nohup.c	8.1 (Berkeley) 6/6/93";
43#endif
44static const char rcsid[] =
45  "$FreeBSD: head/usr.bin/nohup/nohup.c 50477 1999-08-28 01:08:13Z peter $";
46#endif /* not lint */
47
48#include <sys/param.h>
49#include <sys/stat.h>
50
51#include <err.h>
52#include <errno.h>
53#include <fcntl.h>
54#include <signal.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <string.h>
58#include <unistd.h>
59
60void dofile __P((void));
61static void usage __P((void));
62
63int
64main(argc, argv)
65	int argc;
66	char *argv[];
67{
68	if (argc < 2)
69		usage();
70
71	if (isatty(STDOUT_FILENO))
72		dofile();
73	if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1) {
74		/* may have just closed stderr */
75		(void)fprintf(stdin, "nohup: %s\n", strerror(errno));
76		exit(1);
77	}
78
79	(void)signal(SIGHUP, SIG_IGN);
80	(void)signal(SIGQUIT, SIG_IGN);
81
82	execvp(argv[1], &argv[1]);
83	err(1, "%s", argv[1]);
84}
85
86void
87dofile()
88{
89	int append;
90	int fd;
91	char *p, path[MAXPATHLEN];
92
93#define	FILENAME	"nohup.out"
94	p = FILENAME;
95	append = !access(p, F_OK);
96	if ((fd = open(p, O_RDWR|O_CREAT, S_IRUSR | S_IWUSR)) >= 0)
97		goto dupit;
98	if ((p = getenv("HOME"))) {
99		(void)strcpy(path, p);
100		(void)strcat(path, "/");
101		(void)strcat(path, FILENAME);
102		append = !access(path, F_OK);
103		if ((fd = open(p = path,
104		    O_RDWR|O_CREAT, S_IRUSR | S_IWUSR)) >= 0)
105			goto dupit;
106	}
107	errx(1, "can't open a nohup.out file");
108
109dupit:	(void)lseek(fd, (off_t)0, SEEK_END);
110	if (dup2(fd, STDOUT_FILENO) == -1)
111		err(1, NULL);
112	if (append)
113		(void)fprintf(stderr, "appending output to existing %s\n", p);
114	else
115		(void)fprintf(stderr, "sending output to %s\n", p);
116}
117
118void
119usage()
120{
121	(void)fprintf(stderr, "usage: nohup command\n");
122	exit(1);
123}
124