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#include <sys/capsicum.h>
33#include <sys/queue.h>
34#include <sys/stat.h>
35#include <sys/types.h>
36
37#include <capsicum_helpers.h>
38#include <err.h>
39#include <errno.h>
40#include <fcntl.h>
41#include <signal.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45#include <unistd.h>
46
47struct entry {
48	int fd;
49	const char *name;
50	STAILQ_ENTRY(entry) entries;
51};
52static STAILQ_HEAD(, entry) head = STAILQ_HEAD_INITIALIZER(head);
53
54static void add(int, const char *);
55static void usage(void) __dead2;
56
57int
58main(int argc, char *argv[])
59{
60	struct entry *p;
61	int n, fd, rval, wval;
62	char *bp;
63	int append, ch, exitval;
64	char *buf;
65#define	BSIZE (8 * 1024)
66
67	append = 0;
68	while ((ch = getopt(argc, argv, "ai")) != -1)
69		switch((char)ch) {
70		case 'a':
71			append = 1;
72			break;
73		case 'i':
74			(void)signal(SIGINT, SIG_IGN);
75			break;
76		case '?':
77		default:
78			usage();
79		}
80	argv += optind;
81	argc -= optind;
82
83	if ((buf = malloc(BSIZE)) == NULL)
84		err(1, "malloc");
85
86	if (caph_limit_stdin() == -1 || caph_limit_stderr() == -1)
87		err(EXIT_FAILURE, "unable to limit stdio");
88
89	add(STDOUT_FILENO, "stdout");
90
91	for (exitval = 0; *argv; ++argv)
92		if ((fd = open(*argv, append ? O_WRONLY|O_CREAT|O_APPEND :
93		    O_WRONLY|O_CREAT|O_TRUNC, DEFFILEMODE)) < 0) {
94			warn("%s", *argv);
95			exitval = 1;
96		} else
97			add(fd, *argv);
98
99	if (caph_enter() < 0)
100		err(EXIT_FAILURE, "unable to enter capability mode");
101	while ((rval = read(STDIN_FILENO, buf, BSIZE)) > 0)
102		STAILQ_FOREACH(p, &head, entries) {
103			n = rval;
104			bp = buf;
105			do {
106				if ((wval = write(p->fd, bp, n)) == -1) {
107					warn("%s", p->name);
108					exitval = 1;
109					break;
110				}
111				bp += wval;
112			} while (n -= wval);
113		}
114	if (rval < 0)
115		err(1, "read");
116	exit(exitval);
117}
118
119static void
120usage(void)
121{
122	(void)fprintf(stderr, "usage: tee [-ai] [file ...]\n");
123	exit(1);
124}
125
126static void
127add(int fd, const char *name)
128{
129	struct entry *p;
130	cap_rights_t rights;
131
132	if (fd == STDOUT_FILENO) {
133		if (caph_limit_stdout() == -1)
134			err(EXIT_FAILURE, "unable to limit stdout");
135	} else {
136		cap_rights_init(&rights, CAP_WRITE, CAP_FSTAT);
137		if (caph_rights_limit(fd, &rights) < 0)
138			err(EXIT_FAILURE, "unable to limit rights");
139	}
140
141	if ((p = malloc(sizeof(struct entry))) == NULL)
142		err(1, "malloc");
143	p->fd = fd;
144	p->name = name;
145	STAILQ_INSERT_HEAD(&head, p, entries);
146}
147