1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 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#if 0
33#ifndef lint
34static char const copyright[] =
35"@(#) Copyright (c) 1989, 1993\n\
36	The Regents of the University of California.  All rights reserved.\n";
37#endif /* not lint */
38
39#ifndef lint
40static char sccsid[] = "@(#)echo.c	8.1 (Berkeley) 5/31/93";
41#endif /* not lint */
42#endif
43#include <sys/cdefs.h>
44__FBSDID("$FreeBSD$");
45
46#include <sys/types.h>
47#include <sys/uio.h>
48
49#include <assert.h>
50#include <capsicum_helpers.h>
51#include <err.h>
52#include <errno.h>
53#include <limits.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57
58/*
59 * Report an error and exit.
60 * Use it instead of err(3) to avoid linking-in stdio.
61 */
62static __dead2 void
63errexit(const char *prog, const char *reason)
64{
65	char *errstr = strerror(errno);
66	write(STDERR_FILENO, prog, strlen(prog));
67	write(STDERR_FILENO, ": ", 2);
68	write(STDERR_FILENO, reason, strlen(reason));
69	write(STDERR_FILENO, ": ", 2);
70	write(STDERR_FILENO, errstr, strlen(errstr));
71	write(STDERR_FILENO, "\n", 1);
72	exit(1);
73}
74
75int
76main(int argc, char *argv[])
77{
78	int nflag;	/* if not set, output a trailing newline. */
79	int veclen;	/* number of writev arguments. */
80	struct iovec *iov, *vp; /* Elements to write, current element. */
81	char space[] = " ";
82	char newline[] = "\n";
83	char *progname = argv[0];
84
85	if (caph_limit_stdio() < 0 || caph_enter() < 0)
86		err(1, "capsicum");
87
88	/* This utility may NOT do getopt(3) option parsing. */
89	if (*++argv && !strcmp(*argv, "-n")) {
90		++argv;
91		--argc;
92		nflag = 1;
93	} else
94		nflag = 0;
95
96	veclen = (argc >= 2) ? (argc - 2) * 2 + 1 : 0;
97
98	if ((vp = iov = malloc((veclen + 1) * sizeof(struct iovec))) == NULL)
99		errexit(progname, "malloc");
100
101	while (argv[0] != NULL) {
102		size_t len;
103
104		len = strlen(argv[0]);
105
106		/*
107		 * If the next argument is NULL then this is the last argument,
108		 * therefore we need to check for a trailing \c.
109		 */
110		if (argv[1] == NULL) {
111			/* is there room for a '\c' and is there one? */
112			if (len >= 2 &&
113			    argv[0][len - 2] == '\\' &&
114			    argv[0][len - 1] == 'c') {
115				/* chop it and set the no-newline flag. */
116				len -= 2;
117				nflag = 1;
118			}
119		}
120		vp->iov_base = *argv;
121		vp++->iov_len = len;
122		if (*++argv) {
123			vp->iov_base = space;
124			vp++->iov_len = 1;
125		}
126	}
127	if (!nflag) {
128		veclen++;
129		vp->iov_base = newline;
130		vp++->iov_len = 1;
131	}
132	/* assert(veclen == (vp - iov)); */
133	while (veclen) {
134		int nwrite;
135
136		nwrite = (veclen > IOV_MAX) ? IOV_MAX : veclen;
137		if (writev(STDOUT_FILENO, iov, nwrite) == -1)
138			errexit(progname, "write");
139		iov += nwrite;
140		veclen -= nwrite;
141	}
142	return 0;
143}
144