xref: /freebsd/usr.bin/tee/tee.c (revision 3c4ba5f55438f7afd4f4b0b56f88f2bb505fd6a6)
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 static const char rcsid[] =
43   "$FreeBSD$";
44 #endif /* not lint */
45 
46 #include <sys/capsicum.h>
47 #include <sys/queue.h>
48 #include <sys/stat.h>
49 #include <sys/types.h>
50 
51 #include <capsicum_helpers.h>
52 #include <err.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <signal.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60 
61 struct entry {
62 	int fd;
63 	const char *name;
64 	STAILQ_ENTRY(entry) entries;
65 };
66 static STAILQ_HEAD(, entry) head = STAILQ_HEAD_INITIALIZER(head);
67 
68 static void add(int, const char *);
69 static void usage(void);
70 
71 int
72 main(int argc, char *argv[])
73 {
74 	struct entry *p;
75 	int n, fd, rval, wval;
76 	char *bp;
77 	int append, ch, exitval;
78 	char *buf;
79 #define	BSIZE (8 * 1024)
80 
81 	append = 0;
82 	while ((ch = getopt(argc, argv, "ai")) != -1)
83 		switch((char)ch) {
84 		case 'a':
85 			append = 1;
86 			break;
87 		case 'i':
88 			(void)signal(SIGINT, SIG_IGN);
89 			break;
90 		case '?':
91 		default:
92 			usage();
93 		}
94 	argv += optind;
95 	argc -= optind;
96 
97 	if ((buf = malloc(BSIZE)) == NULL)
98 		err(1, "malloc");
99 
100 	if (caph_limit_stdin() == -1 || caph_limit_stderr() == -1)
101 		err(EXIT_FAILURE, "unable to limit stdio");
102 
103 	add(STDOUT_FILENO, "stdout");
104 
105 	for (exitval = 0; *argv; ++argv)
106 		if ((fd = open(*argv, append ? O_WRONLY|O_CREAT|O_APPEND :
107 		    O_WRONLY|O_CREAT|O_TRUNC, DEFFILEMODE)) < 0) {
108 			warn("%s", *argv);
109 			exitval = 1;
110 		} else
111 			add(fd, *argv);
112 
113 	if (caph_enter() < 0)
114 		err(EXIT_FAILURE, "unable to enter capability mode");
115 	while ((rval = read(STDIN_FILENO, buf, BSIZE)) > 0)
116 		STAILQ_FOREACH(p, &head, entries) {
117 			n = rval;
118 			bp = buf;
119 			do {
120 				if ((wval = write(p->fd, bp, n)) == -1) {
121 					warn("%s", p->name);
122 					exitval = 1;
123 					break;
124 				}
125 				bp += wval;
126 			} while (n -= wval);
127 		}
128 	if (rval < 0)
129 		err(1, "read");
130 	exit(exitval);
131 }
132 
133 static void
134 usage(void)
135 {
136 	(void)fprintf(stderr, "usage: tee [-ai] [file ...]\n");
137 	exit(1);
138 }
139 
140 static void
141 add(int fd, const char *name)
142 {
143 	struct entry *p;
144 	cap_rights_t rights;
145 
146 	if (fd == STDOUT_FILENO) {
147 		if (caph_limit_stdout() == -1)
148 			err(EXIT_FAILURE, "unable to limit stdout");
149 	} else {
150 		cap_rights_init(&rights, CAP_WRITE, CAP_FSTAT);
151 		if (caph_rights_limit(fd, &rights) < 0)
152 			err(EXIT_FAILURE, "unable to limit rights");
153 	}
154 
155 	if ((p = malloc(sizeof(struct entry))) == NULL)
156 		err(1, "malloc");
157 	p->fd = fd;
158 	p->name = name;
159 	STAILQ_INSERT_HEAD(&head, p, entries);
160 }
161