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>... */
51 int snprintf_ss(char *restrict, size_t, const char *restrict, ...)
52 __printflike(3, 4);
53 int 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 */
61 ssize_t
read_block(int fd,void * buf,size_t len)62 read_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 */
85 ssize_t
pread_block(int fd,void * buf,size_t len,off_t fdpos)86 pread_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
116 void
err_ss(int exit_value,const char * msg)117 err_ss(int exit_value, const char *msg)
118 {
119 warn_ss(msg);
120 _Exit(exit_value);
121 }
122
123 void
errx_ss(int exit_value,const char * format,...)124 errx_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
134 void
warn_ss(const char * msg)135 warn_ss(const char *msg)
136 {
137 int error = errno;
138
139 warnx_ss("%s: %s", msg, strerror(error));
140
141 errno = error;
142 }
143
144 void
warnx_ss(const char * format,...)145 warnx_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
154 void
vwarnx_ss(const char * format,va_list va)155 vwarnx_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
174 void
block_signals(sigset_t * old_sigmask)175 block_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
183 void
restore_sigmask(const sigset_t * sigmask)184 restore_sigmask(const sigset_t *sigmask)
185 {
186
187 (void)sigprocmask(SIG_SETMASK, sigmask, NULL);
188 }
189