xref: /freebsd/usr.bin/tee/tee.c (revision d34048812292b714a0bf99967270d18fe3097c62)
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/stat.h>
48 #include <sys/types.h>
49 
50 #include <capsicum_helpers.h>
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 typedef struct _list {
61 	struct _list *next;
62 	int fd;
63 	const char *name;
64 } LIST;
65 static LIST *head;
66 
67 static void add(int, const char *);
68 static void usage(void);
69 
70 int
71 main(int argc, char *argv[])
72 {
73 	LIST *p;
74 	int n, fd, rval, wval;
75 	char *bp;
76 	int append, ch, exitval;
77 	char *buf;
78 #define	BSIZE (8 * 1024)
79 
80 	append = 0;
81 	while ((ch = getopt(argc, argv, "ai")) != -1)
82 		switch((char)ch) {
83 		case 'a':
84 			append = 1;
85 			break;
86 		case 'i':
87 			(void)signal(SIGINT, SIG_IGN);
88 			break;
89 		case '?':
90 		default:
91 			usage();
92 		}
93 	argv += optind;
94 	argc -= optind;
95 
96 	if ((buf = malloc(BSIZE)) == NULL)
97 		err(1, "malloc");
98 
99 	if (caph_limit_stdin() == -1 || caph_limit_stderr() == -1)
100 		err(EXIT_FAILURE, "unable to limit stdio");
101 
102 	add(STDOUT_FILENO, "stdout");
103 
104 	for (exitval = 0; *argv; ++argv)
105 		if ((fd = open(*argv, append ? O_WRONLY|O_CREAT|O_APPEND :
106 		    O_WRONLY|O_CREAT|O_TRUNC, DEFFILEMODE)) < 0) {
107 			warn("%s", *argv);
108 			exitval = 1;
109 		} else
110 			add(fd, *argv);
111 
112 	if (caph_enter() < 0)
113 		err(EXIT_FAILURE, "unable to enter capability mode");
114 	while ((rval = read(STDIN_FILENO, buf, BSIZE)) > 0)
115 		for (p = head; p; p = p->next) {
116 			n = rval;
117 			bp = buf;
118 			do {
119 				if ((wval = write(p->fd, bp, n)) == -1) {
120 					warn("%s", p->name);
121 					exitval = 1;
122 					break;
123 				}
124 				bp += wval;
125 			} while (n -= wval);
126 		}
127 	if (rval < 0)
128 		err(1, "read");
129 	exit(exitval);
130 }
131 
132 static void
133 usage(void)
134 {
135 	(void)fprintf(stderr, "usage: tee [-ai] [file ...]\n");
136 	exit(1);
137 }
138 
139 static void
140 add(int fd, const char *name)
141 {
142 	LIST *p;
143 	cap_rights_t rights;
144 
145 	if (fd == STDOUT_FILENO) {
146 		if (caph_limit_stdout() == -1)
147 			err(EXIT_FAILURE, "unable to limit stdout");
148 	} else {
149 		cap_rights_init(&rights, CAP_WRITE, CAP_FSTAT);
150 		if (caph_rights_limit(fd, &rights) < 0)
151 			err(EXIT_FAILURE, "unable to limit rights");
152 	}
153 
154 	if ((p = malloc(sizeof(LIST))) == NULL)
155 		err(1, "malloc");
156 	p->fd = fd;
157 	p->name = name;
158 	p->next = head;
159 	head = p;
160 }
161