xref: /netbsd/usr.bin/nohup/nohup.c (revision bf9ec67e)
1 /*	$NetBSD: nohup.c,v 1.10 2001/09/16 16:34:43 wiz 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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #ifndef lint
38 __COPYRIGHT(
39     "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
40  All rights reserved.\n");
41 #endif /* not lint */
42 
43 #ifndef lint
44 #if 0
45 static char sccsid[] = "@(#)nohup.c	5.4 (Berkeley) 6/1/90";
46 #endif
47 __RCSID("$NetBSD: nohup.c,v 1.10 2001/09/16 16:34:43 wiz Exp $");
48 #endif /* not lint */
49 
50 #include <sys/param.h>
51 #include <sys/file.h>
52 #include <sys/stat.h>
53 #include <fcntl.h>
54 #include <unistd.h>
55 #include <signal.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <errno.h>
60 
61 static void dofile __P((void));
62 static void usage __P((void));
63 int main __P((int, char **));
64 
65 /* nohup shall exit with one of the following values:
66    126 - The utility was found but could not be invoked.
67    127 - An error occurred in the nohup utility, or the utility could
68          not be found. */
69 #define EXIT_NOEXEC	126
70 #define EXIT_NOTFOUND	127
71 #define EXIT_MISC	127
72 
73 int
74 main(argc, argv)
75 	int argc;
76 	char **argv;
77 {
78 	int exit_status;
79 
80 	while (getopt(argc, argv, "") != -1) {
81 		usage();
82 	}
83 	argc -= optind;
84 	argv += optind;
85 
86 	if (argc < 1)
87 		usage();
88 
89 	if (isatty(STDOUT_FILENO))
90 		dofile();
91 	if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) == -1) {
92 		/* may have just closed stderr */
93 		(void)fprintf(stdin, "nohup: %s\n", strerror(errno));
94 		exit(EXIT_MISC);
95 	}
96 
97 	/* The nohup utility shall take the standard action for all signals
98 	   except that SIGHUP shall be ignored. */
99 	(void)signal(SIGHUP, SIG_IGN);
100 
101 	execvp(argv[0], &argv[0]);
102 	exit_status = (errno == ENOENT) ? EXIT_NOTFOUND : EXIT_NOEXEC;
103 	(void)fprintf(stderr, "nohup: %s: %s\n", argv[0], strerror(errno));
104 	exit(exit_status);
105 }
106 
107 static void
108 dofile()
109 {
110 	int fd;
111 	char *p, path[MAXPATHLEN];
112 
113 	/* If the standard output is a terminal, all output written to
114 	   its standard output shall be appended to the end of the file
115 	   nohup.out in the current directory.  If nohup.out cannot be
116 	   created or opened for appending, the output shall be appended
117 	   to the end of the file nohup.out in the directory specified
118 	   by the HOME environment variable.
119 
120 	   If a file is created, the file's permission bits shall be
121 	   set to S_IRUSR | S_IWUSR. */
122 #define	FILENAME	"nohup.out"
123 	p = FILENAME;
124 	if ((fd = open(p, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
125 		goto dupit;
126 	if ((p = getenv("HOME")) != NULL) {
127 		(void)strcpy(path, p);
128 		(void)strcat(path, "/");
129 		(void)strcat(path, FILENAME);
130 		if ((fd = open(p = path, O_RDWR|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR)) >= 0)
131 			goto dupit;
132 	}
133 	(void)fprintf(stderr, "nohup: can't open a nohup.out file.\n");
134 	exit(EXIT_MISC);
135 
136 dupit:	(void)lseek(fd, 0L, SEEK_END);
137 	if (dup2(fd, STDOUT_FILENO) == -1) {
138 		(void)fprintf(stderr, "nohup: %s\n", strerror(errno));
139 		exit(EXIT_MISC);
140 	}
141 	(void)fprintf(stderr, "sending output to %s\n", p);
142 }
143 
144 static void
145 usage()
146 {
147 	(void)fprintf(stderr, "usage: nohup utility [argument ...]\n");
148 	exit(EXIT_MISC);
149 }
150