1 /*
2 * This file contains functions to deal with compatibility issues across OSes.
3 *
4 * The initial version of this file is a near-verbatim concatenation of the
5 * following three source files:
6 * clock_gettime.c
7 * daemon.c
8 * strl.c
9 * History of this code prior to the creation of this file can be found
10 * in the histories of those files.
11 *
12 * This file is Copyright (c)2017-2019 by the GPSD project
13 * SPDX-License-Identifier: BSD-2-clause
14 */
15
16 #include "gpsd_config.h" /* must be before all includes */
17
18 #include "os_compat.h"
19
20 #ifndef HAVE_CLOCK_GETTIME
21
22 /* Simulate ANSI/POSIX clock_gettime() on platforms that don't have it */
23
24 #include <time.h>
25 #include <sys/time.h>
26
27 /*
28 * Note that previous versions of this code made use of clock_get_time()
29 * on OSX, as a way to get time of day with nanosecond resolution. But
30 * it turns out that clock_get_time() only has microsecond resolution,
31 * in spite of the data format, and it's also substantially slower than
32 * gettimeofday(). Thus, it makes no sense to do anything special for OSX.
33 */
34
clock_gettime(clockid_t clk_id,struct timespec * ts)35 int clock_gettime(clockid_t clk_id, struct timespec *ts)
36 {
37 (void) clk_id;
38 struct timeval tv;
39 if (gettimeofday(&tv, NULL) < 0)
40 return -1;
41 ts->tv_sec = tv.tv_sec;
42 ts->tv_nsec = tv.tv_usec * 1000;
43 return 0;
44 }
45 #endif /* HAVE_CLOCK_GETTIME */
46
47 /* End of clock_gettime section */
48
49 #ifndef HAVE_DAEMON
50 /* Simulate Linux/BSD daemon() on platforms that don't have it */
51
52 #ifdef HAVE_FORK
53
54 #include <stdlib.h>
55 #include <sys/types.h>
56 #include <sys/stat.h>
57 #include <fcntl.h>
58 #include <unistd.h>
59
60 #if defined (HAVE_PATH_H)
61 #include <paths.h>
62 #else
63 #if !defined (_PATH_DEVNULL)
64 #define _PATH_DEVNULL "/dev/null"
65 #endif
66 #endif
67
os_daemon(int nochdir,int noclose)68 int os_daemon(int nochdir, int noclose)
69 /* compatible with the daemon(3) found on Linuxes and BSDs */
70 {
71 int fd;
72
73 switch (fork()) {
74 case -1:
75 return -1;
76 case 0: /* child side */
77 break;
78 default: /* parent side */
79 exit(EXIT_SUCCESS);
80 }
81
82 if (setsid() == -1)
83 return -1;
84 if ((nochdir==0) && (chdir("/") == -1))
85 return -1;
86 if ((noclose==0) && (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
87 (void)dup2(fd, STDIN_FILENO);
88 (void)dup2(fd, STDOUT_FILENO);
89 (void)dup2(fd, STDERR_FILENO);
90 if (fd > 2)
91 (void)close(fd);
92 }
93 /* coverity[leaked_handle] Intentional handle duplication */
94 return 0;
95 }
96 #else /* !HAVE_FORK */
97
98 #include <errno.h>
99
os_daemon(int nochdir,int noclose)100 int os_daemon(int nochdir, int noclose)
101 {
102 (void) nochdir; (void) noclose;
103 errno = EPERM;
104 return -1;
105 }
106
107 #endif /* !HAVE_FORK */
108
109 #else /* HAVE_DAEMON */
110
111 #if defined (__linux__) || defined (__GLIBC__)
112
113 #include <unistd.h> /* for daemon() */
114
115 #elif defined(__APPLE__) /* !__linux__ */
116
117 /*
118 * Avoid the OSX deprecation warning.
119 *
120 * Note that on OSX, real daemons like gpsd should run via launchd rather than
121 * self-daemonizing, but we use daemon() for other tools as well.
122 *
123 * There doesn't seem to be an easy way to avoid the warning other than by
124 * providing our own declaration to override the deprecation-flagged version.
125 * Fortunately, the function signature is pretty well frozen at this point.
126 *
127 * Until we fix the kludge where all this code has to be additionally compiled
128 * as C++ for the Qt library, we need this to be compilable as C++ as well.
129 */
130 #ifdef __cplusplus
131 extern "C" {
132 #endif
133
134 int daemon(int nochdir, int noclose);
135
136 #ifdef __cplusplus
137 }
138 #endif
139
140 #else /* !__linux__ && !__APPLE__ */
141
142 #include <stdlib.h>
143
144 #endif /* !__linux__ && !__APPLE__ */
145
os_daemon(int nochdir,int noclose)146 int os_daemon(int nochdir, int noclose)
147 {
148 return daemon(nochdir, noclose);
149 }
150
151 #endif /* HAVE_DAEMON */
152
153 /* End of daemon section */
154
155 /* Provide syslog() on platforms that don't have it */
156
157 #ifndef HAVE_SYSLOG_H
158 #include "compiler.h"
159 #include <stdarg.h>
160 #include <stdio.h>
161 /*
162 * Minimal syslog() fallback to print to stderr
163 *
164 */
syslog(int priority UNUSED,const char * format,...)165 PRINTF_FUNC(2, 3) void syslog(int priority UNUSED, const char *format, ...)
166 {
167 /* ATM ignore priority (i.e. don't even both prepending to output) */
168 char buf[BUFSIZ];
169 va_list ap;
170 va_start(ap, format);
171 /* Always append a new line to the message */
172 (void)vsnprintf(buf, sizeof(buf) - 2, format, ap);
173 (void)fprintf(stderr, "%s\n", buf);
174 va_end(ap);
175 }
176
openlog(const char * __ident UNUSED,int __option UNUSED,int __facility UNUSED)177 void openlog (const char *__ident UNUSED, int __option UNUSED, int __facility UNUSED)
178 {
179 (void)fprintf(stderr, "Warning openlog() not available\n");
180 }
181
closelog(void)182 void closelog (void)
183 {
184 }
185 #endif /* !HAVE_SYSLOG_H */
186
187 /* End of syslog section */
188
189 /*
190 * Provide BSD strlcat()/strlcpy() on platforms that don't have it
191 *
192 * These versions use memcpy and strlen() because they are often
193 * heavily optimized down to assembler level. Thus, likely to be
194 * faster even with the function call overhead.
195 */
196
197 #ifndef HAVE_STRLCAT
198
199 #include <string.h>
200
201 /*
202 * Appends src to string dst of size siz (unlike strncat, siz is the
203 * full size of dst, not space left). At most siz-1 characters
204 * will be copied. Always NUL terminates (unless siz <= strlen(dst)).
205 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
206 * If retval >= siz, truncation occurred.
207 */
strlcat(char * dst,const char * src,size_t siz)208 size_t strlcat(char *dst, const char *src, size_t siz)
209 {
210 size_t slen = strlen(src);
211 size_t dlen = strlen(dst);
212 if (siz != 0) {
213 if (dlen + slen < siz)
214 memcpy(dst + dlen, src, slen + 1);
215 else {
216 memcpy(dst + dlen, src, siz - dlen - 1);
217 dst[siz - 1] = '\0';
218 }
219 }
220 return dlen + slen;
221 }
222
223 #ifdef __UNUSED__
224 /* $OpenBSD: strlcat.c,v 1.13 2005/08/08 08:05:37 espie Exp $ */
225
226 /*
227 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
228 *
229 * Permission to use, copy, modify, and distribute this software for any
230 * purpose with or without fee is hereby granted, provided that the above
231 * copyright notice and this permission notice appear in all copies.
232 *
233 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
234 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
235 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
236 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
237 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
238 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
239 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
240 */
241
strlcat(char * dst,const char * src,size_t siz)242 size_t strlcat(char *dst, const char *src, size_t siz)
243 {
244 char *d = dst;
245 const char *s = src;
246 size_t n = siz;
247 size_t dlen;
248
249 /* Find the end of dst and adjust bytes left but don't go past end */
250 while (n-- != 0 && *d != '\0')
251 d++;
252 dlen = (size_t) (d - dst);
253 n = siz - dlen;
254
255 if (n == 0)
256 return (dlen + strlen(s));
257 while (*s != '\0') {
258 if (n != 1) {
259 *d++ = *s;
260 n--;
261 }
262 s++;
263 }
264 *d = '\0';
265
266 return (dlen + (s - src)); /* count does not include NUL */
267 }
268 #endif /* __UNUSED__ */
269 #endif /* !HAVE_STRLCAT */
270
271 #ifndef HAVE_STRLCPY
272
273 #include <string.h>
274
275 /*
276 * Copy src to string dst of size siz. At most siz-1 characters
277 * will be copied. Always NUL terminates (unless siz == 0).
278 * Returns strlen(src); if retval >= siz, truncation occurred.
279 */
strlcpy(char * dst,const char * src,size_t siz)280 size_t strlcpy(char *dst, const char *src, size_t siz)
281 {
282 size_t len = strlen(src);
283 if (siz != 0) {
284 if (len >= siz) {
285 memcpy(dst, src, siz - 1);
286 dst[siz - 1] = '\0';
287 } else
288 memcpy(dst, src, len + 1);
289 }
290 return len;
291 }
292
293 #endif /* !HAVE_STRLCPY */
294
295 /* End of strlcat()/strlcpy() section */
296
297 /*
298 * Provide sincos() on platforms that don't have it.
299 * This just uses the usual sin() and cos(), with no speed benefit.
300 * It doesn't worry about the corner case where the +-infinity argument
301 * may raise the "invalid" exception before storing both NaN results.
302 */
303
304 #ifndef HAVE_SINCOS
305
306 #include <math.h>
307
sincos(double x,double * sinp,double * cosp)308 void sincos(double x, double *sinp, double *cosp)
309 {
310 *sinp = sin(x);
311 *cosp = cos(x);
312 }
313
314 #endif /* !HAVE_SINCOS */
315
316 /* End of sincos() section. */
317