1/*	$NetBSD: utils.c,v 1.6 2017/03/21 13:56:38 riastradh Exp $	*/
2
3/*-
4 * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__RCSID("$NetBSD: utils.c,v 1.6 2017/03/21 13:56:38 riastradh Exp $");
34
35#include <sys/types.h>
36
37#include <assert.h>
38#include <err.h>
39#include <errno.h>
40#include <inttypes.h>
41#include <limits.h>
42#include <signal.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47
48#include "common.h"
49
50/* XXX Seems to be missing from <stdio.h>...  */
51int	snprintf_ss(char *restrict, size_t, const char *restrict, ...)
52	    __printflike(3, 4);
53int	vsnprintf_ss(char *restrict, size_t, const char *restrict, va_list)
54	    __printflike(3, 0);
55
56#include "utils.h"
57
58/*
59 * Read, returning partial data only at end of file.
60 */
61ssize_t
62read_block(int fd, void *buf, size_t len)
63{
64	char *p = buf;
65	size_t n = len;
66	const char *const end __diagused = p + n;
67	ssize_t nread = 0;
68
69	while (0 < n && (nread = read(fd, p, n)) != 0) {
70		if (nread == -1)
71			return -1;
72		p += MIN(n, (size_t)nread);
73		n -= MIN(n, (size_t)nread);
74		assert(p + n == end);
75	}
76
77	assert(n == 0 || nread == 0); /* complete read or EOF */
78	return len - n;
79}
80
81/*
82 * Read from a specified position, returning partial data only at end
83 * of file.
84 */
85ssize_t
86pread_block(int fd, void *buf, size_t len, off_t fdpos)
87{
88	char *p = buf;
89	size_t n = len;
90	const char *const end __diagused = p + n;
91	ssize_t nread = 0;
92
93	assert(0 <= fdpos);
94	assert(n <= OFF_MAX - (uintmax_t)fdpos);
95	const off_t endpos __diagused = fdpos + n;
96
97	while (0 < n && (nread = pread(fd, p, n, fdpos)) != 0) {
98		if (nread == -1)
99			return -1;
100		fdpos += MIN(n, (size_t)nread);
101		p += MIN(n, (size_t)nread);
102		n -= MIN(n, (size_t)nread);
103		assert(p + n == end);
104		assert(fdpos + (off_t)n == endpos);
105	}
106
107	assert(n == 0 || nread == 0); /* complete read or EOF */
108	return len - n;
109}
110
111/*
112 * Signal-safe err/warn utilities.  The errno varieties are limited to
113 * having no format arguments for reasons of laziness.
114 */
115
116void
117err_ss(int exit_value, const char *msg)
118{
119	warn_ss(msg);
120	_Exit(exit_value);
121}
122
123void
124errx_ss(int exit_value, const char *format, ...)
125{
126	va_list va;
127
128	va_start(va, format);
129	vwarnx_ss(format, va);
130	va_end(va);
131	_Exit(exit_value);
132}
133
134void
135warn_ss(const char *msg)
136{
137	int error = errno;
138
139	warnx_ss("%s: %s", msg, strerror(error));
140
141	errno = error;
142}
143
144void
145warnx_ss(const char *format, ...)
146{
147	va_list va;
148
149	va_start(va, format);
150	vwarnx_ss(format, va);
151	va_end(va);
152}
153
154void
155vwarnx_ss(const char *format, va_list va)
156{
157	char buf[128];
158
159	(void)strlcpy(buf, getprogname(), sizeof(buf));
160	(void)strlcat(buf, ": ", sizeof(buf));
161
162	const int n = vsnprintf_ss(&buf[strlen(buf)], (sizeof(buf) -
163		strlen(buf)), format, va);
164	if (n <= 0) {
165		const char fallback[] =
166		    "vndcompress: Help!  I'm trapped in a signal handler!\n";
167		(void)write(STDERR_FILENO, fallback, __arraycount(fallback));
168	} else {
169		(void)strlcat(buf, "\n", sizeof(buf));
170		(void)write(STDERR_FILENO, buf, strlen(buf));
171	}
172}
173
174void
175block_signals(sigset_t *old_sigmask)
176{
177	sigset_t block;
178
179	(void)sigfillset(&block);
180	(void)sigprocmask(SIG_BLOCK, &block, old_sigmask);
181}
182
183void
184restore_sigmask(const sigset_t *sigmask)
185{
186
187	(void)sigprocmask(SIG_SETMASK, sigmask, NULL);
188}
189