xref: /dragonfly/bin/notty/notty.c (revision ab709bfb)
1 /*
2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
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  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * $DragonFly: src/bin/notty/notty.c,v 1.2 2008/06/24 21:13:26 thomas Exp $
35  */
36 /*
37  * NOTTY.C - program to disconnect a program from the tty and close
38  *           stdin, stdout, and stderr (-012 to specify which descriptors
39  *           to leave open).
40  *
41  * NOTTY [-012] <command>
42  */
43 
44 #include <sys/types.h>
45 #include <sys/ioctl.h>
46 #include <sys/time.h>
47 #include <sys/wait.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <stdarg.h>
52 #include <fcntl.h>
53 #include <signal.h>
54 #include <unistd.h>
55 
56 static void usage(void);
57 
58 int
59 main(int ac, char **av)
60 {
61 	const char *opts = "";
62 	int ttyfd;
63 	int fd;
64 
65 	if (ac == 1)
66 		usage();
67 
68 	if (av[1]) {
69 		if (av[1][0] == '-') {
70 			opts = av[1];
71 			++av;
72 		}
73 	}
74 
75 
76 	ttyfd = open("/dev/null", O_RDWR);
77 
78 	if (strchr(opts, '0') == NULL && ttyfd != 0)
79 		dup2(ttyfd, 0);
80 	if (strchr(opts, '1') == NULL && ttyfd != 1)
81 		dup2(ttyfd, 1);
82 	if (strchr(opts, '2') == NULL && ttyfd != 2)
83 		dup2(ttyfd, 2);
84 
85 	if (ttyfd > 2)
86 		close(ttyfd);
87 
88 	fd = open("/dev/tty", O_RDWR);
89 	if (fd >= 0) {
90 		ioctl(fd, TIOCNOTTY, 0);
91 		close(fd);
92 	}
93 
94 	if (fork() == 0) {
95 		setsid();
96 		exit(execvp(av[1], av + 1));
97 	}
98 	exit(0);
99 }
100 
101 static void
102 usage(void)
103 {
104 	fprintf(stderr, "notty [-012] command args ...\n");
105 	exit(1);
106 }
107 
108