xref: /freebsd/usr.bin/tee/tee.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1988, 1993
5  *	The Regents of the University of California.  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 #ifndef lint
33 static const char copyright[] =
34 "@(#) Copyright (c) 1988, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n";
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)tee.c	8.1 (Berkeley) 6/6/93";
41 #endif
42 #endif /* not lint */
43 
44 #include <sys/capsicum.h>
45 #include <sys/queue.h>
46 #include <sys/stat.h>
47 #include <sys/types.h>
48 
49 #include <capsicum_helpers.h>
50 #include <err.h>
51 #include <errno.h>
52 #include <fcntl.h>
53 #include <signal.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 
59 struct entry {
60 	int fd;
61 	const char *name;
62 	STAILQ_ENTRY(entry) entries;
63 };
64 static STAILQ_HEAD(, entry) head = STAILQ_HEAD_INITIALIZER(head);
65 
66 static void add(int, const char *);
67 static void usage(void) __dead2;
68 
69 int
70 main(int argc, char *argv[])
71 {
72 	struct entry *p;
73 	int n, fd, rval, wval;
74 	char *bp;
75 	int append, ch, exitval;
76 	char *buf;
77 #define	BSIZE (8 * 1024)
78 
79 	append = 0;
80 	while ((ch = getopt(argc, argv, "ai")) != -1)
81 		switch((char)ch) {
82 		case 'a':
83 			append = 1;
84 			break;
85 		case 'i':
86 			(void)signal(SIGINT, SIG_IGN);
87 			break;
88 		case '?':
89 		default:
90 			usage();
91 		}
92 	argv += optind;
93 	argc -= optind;
94 
95 	if ((buf = malloc(BSIZE)) == NULL)
96 		err(1, "malloc");
97 
98 	if (caph_limit_stdin() == -1 || caph_limit_stderr() == -1)
99 		err(EXIT_FAILURE, "unable to limit stdio");
100 
101 	add(STDOUT_FILENO, "stdout");
102 
103 	for (exitval = 0; *argv; ++argv)
104 		if ((fd = open(*argv, append ? O_WRONLY|O_CREAT|O_APPEND :
105 		    O_WRONLY|O_CREAT|O_TRUNC, DEFFILEMODE)) < 0) {
106 			warn("%s", *argv);
107 			exitval = 1;
108 		} else
109 			add(fd, *argv);
110 
111 	if (caph_enter() < 0)
112 		err(EXIT_FAILURE, "unable to enter capability mode");
113 	while ((rval = read(STDIN_FILENO, buf, BSIZE)) > 0)
114 		STAILQ_FOREACH(p, &head, entries) {
115 			n = rval;
116 			bp = buf;
117 			do {
118 				if ((wval = write(p->fd, bp, n)) == -1) {
119 					warn("%s", p->name);
120 					exitval = 1;
121 					break;
122 				}
123 				bp += wval;
124 			} while (n -= wval);
125 		}
126 	if (rval < 0)
127 		err(1, "read");
128 	exit(exitval);
129 }
130 
131 static void
132 usage(void)
133 {
134 	(void)fprintf(stderr, "usage: tee [-ai] [file ...]\n");
135 	exit(1);
136 }
137 
138 static void
139 add(int fd, const char *name)
140 {
141 	struct entry *p;
142 	cap_rights_t rights;
143 
144 	if (fd == STDOUT_FILENO) {
145 		if (caph_limit_stdout() == -1)
146 			err(EXIT_FAILURE, "unable to limit stdout");
147 	} else {
148 		cap_rights_init(&rights, CAP_WRITE, CAP_FSTAT);
149 		if (caph_rights_limit(fd, &rights) < 0)
150 			err(EXIT_FAILURE, "unable to limit rights");
151 	}
152 
153 	if ((p = malloc(sizeof(struct entry))) == NULL)
154 		err(1, "malloc");
155 	p->fd = fd;
156 	p->name = name;
157 	STAILQ_INSERT_HEAD(&head, p, entries);
158 }
159