xref: /freebsd/usr.bin/nohup/nohup.c (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb)
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
35 static 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
42 static char sccsid[] = "@(#)nohup.c	8.1 (Berkeley) 6/6/93";
43 #endif
44 static const char rcsid[] =
45 	"$Id$";
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 
60 void dofile __P((void));
61 static void usage __P((void));
62 
63 int
64 main(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 
86 void
87 dofile()
88 {
89 	int fd;
90 	char *p, path[MAXPATHLEN];
91 
92 #define	FILENAME	"nohup.out"
93 	p = FILENAME;
94 	if ((fd = open(p, O_RDWR|O_CREAT, S_IRUSR | S_IWUSR)) >= 0)
95 		goto dupit;
96 	if ((p = getenv("HOME"))) {
97 		(void)strcpy(path, p);
98 		(void)strcat(path, "/");
99 		(void)strcat(path, FILENAME);
100 		if ((fd = open(p = path,
101 		    O_RDWR|O_CREAT, S_IRUSR | S_IWUSR)) >= 0)
102 			goto dupit;
103 	}
104 	errx(1, "can't open a nohup.out file");
105 
106 dupit:	(void)lseek(fd, (off_t)0, SEEK_END);
107 	if (dup2(fd, STDOUT_FILENO) == -1)
108 		err(1, NULL);
109 	(void)fprintf(stderr, "sending output to %s\n", p);
110 }
111 
112 void
113 usage()
114 {
115 	(void)fprintf(stderr, "usage: nohup command\n");
116 	exit(1);
117 }
118