syslog.c 9.0 KB

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  1. /*
  2. * Copyright (c) 1983, 1988, 1993
  3. * The Regents of the University of California. All rights reserved.
  4. *
  5. * Redistribution and use in source and binary forms, with or without
  6. * modification, are permitted provided that the following conditions
  7. * are met:
  8. * 1. Redistributions of source code must retain the above copyright
  9. * notice, this list of conditions and the following disclaimer.
  10. * 2. Redistributions in binary form must reproduce the above copyright
  11. * notice, this list of conditions and the following disclaimer in the
  12. * documentation and/or other materials provided with the distribution.
  13. * 3. All advertising materials mentioning features or use of this software
  14. * must display the following acknowledgement:
  15. * This product includes software developed by the University of
  16. * California, Berkeley and its contributors.
  17. * 4. Neither the name of the University nor the names of its contributors
  18. * may be used to endorse or promote products derived from this software
  19. * without specific prior written permission.
  20. *
  21. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31. * SUCH DAMAGE.
  32. */
  33. #define __FORCE_GLIBC
  34. #define _GNU_SOURCE
  35. #include <features.h>
  36. /*
  37. * SYSLOG -- print message on log file
  38. *
  39. * This routine looks a lot like printf, except that it outputs to the
  40. * log file instead of the standard output. Also:
  41. * adds a timestamp,
  42. * prints the module name in front of the message,
  43. * has some other formatting types (or will sometime),
  44. * adds a newline on the end of the message.
  45. *
  46. * The output of this routine is intended to be read by syslogd(8).
  47. *
  48. * Author: Eric Allman
  49. * Modified to use UNIX domain IPC by Ralph Campbell
  50. * Patched March 12, 1996 by A. Ian Vogelesang <vogelesang@hdshq.com>
  51. * - to correct the handling of message & format string truncation,
  52. * - to visibly tag truncated records to facilitate
  53. * investigation of such Bad Things with grep, and,
  54. * - to correct the handling of case where "write"
  55. * returns after writing only part of the message.
  56. * Rewritten by Martin Mares <mj@atrey.karlin.mff.cuni.cz> on May 14, 1997
  57. * - better buffer overrun checks.
  58. * - special handling of "%m" removed as we use GNU sprintf which handles
  59. * it automatically.
  60. * - Major code cleanup.
  61. */
  62. #include <sys/types.h>
  63. #include <sys/socket.h>
  64. #include <sys/file.h>
  65. #include <sys/signal.h>
  66. #include <sys/syslog.h>
  67. #include <sys/uio.h>
  68. #include <sys/wait.h>
  69. #include <netdb.h>
  70. #include <string.h>
  71. #include <time.h>
  72. #include <unistd.h>
  73. #include <errno.h>
  74. #include <stdarg.h>
  75. #include <paths.h>
  76. #include <stdio.h>
  77. #include <ctype.h>
  78. #include <signal.h>
  79. #ifdef __UCLIBC_HAS_THREADS__
  80. #include <pthread.h>
  81. static pthread_mutex_t mylock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
  82. # define LOCK __pthread_mutex_lock(&mylock)
  83. # define UNLOCK __pthread_mutex_unlock(&mylock);
  84. #else
  85. # define LOCK
  86. # define UNLOCK
  87. #endif
  88. static int LogFile = -1; /* fd for log */
  89. static int connected; /* have done connect */
  90. static int LogStat = 0; /* status bits, set by openlog() */
  91. static const char *LogTag = "syslog"; /* string to tag the entry with */
  92. static int LogFacility = LOG_USER; /* default facility code */
  93. static int LogMask = 0xff; /* mask of priorities to be logged */
  94. static struct sockaddr SyslogAddr; /* AF_UNIX address of local logger */
  95. static void closelog_intern( int );
  96. void syslog( int, const char *, ...);
  97. void vsyslog( int, const char *, va_list );
  98. void openlog( const char *, int, int );
  99. void closelog( void );
  100. int setlogmask(int pmask);
  101. static void
  102. closelog_intern(int to_default)
  103. {
  104. LOCK;
  105. if (LogFile != -1) {
  106. (void) close(LogFile);
  107. }
  108. LogFile = -1;
  109. connected = 0;
  110. if (to_default)
  111. {
  112. LogStat = 0;
  113. LogTag = "syslog";
  114. LogFacility = LOG_USER;
  115. LogMask = 0xff;
  116. }
  117. UNLOCK;
  118. }
  119. static void
  120. sigpipe_handler (int sig)
  121. {
  122. closelog_intern (0);
  123. }
  124. /*
  125. * syslog, vsyslog --
  126. * print message on log file; output is intended for syslogd(8).
  127. */
  128. void
  129. syslog(int pri, const char *fmt, ...)
  130. {
  131. va_list ap;
  132. va_start(ap, fmt);
  133. vsyslog(pri, fmt, ap);
  134. va_end(ap);
  135. }
  136. void
  137. vsyslog( int pri, const char *fmt, va_list ap )
  138. {
  139. register char *p;
  140. char *last_chr, *head_end, *end, *stdp;
  141. time_t now;
  142. int fd, saved_errno;
  143. int rc;
  144. char tbuf[1024]; /* syslogd is unable to handle longer messages */
  145. struct sigaction action, oldaction;
  146. int sigpipe;
  147. memset (&action, 0, sizeof (action));
  148. action.sa_handler = sigpipe_handler;
  149. sigemptyset (&action.sa_mask);
  150. sigpipe = sigaction (SIGPIPE, &action, &oldaction);
  151. saved_errno = errno;
  152. LOCK;
  153. /* See if we should just throw out this message. */
  154. if (!(LogMask & LOG_MASK(LOG_PRI(pri))) || (pri &~ (LOG_PRIMASK|LOG_FACMASK)))
  155. goto getout;
  156. if (LogFile < 0 || !connected)
  157. openlog(LogTag, LogStat | LOG_NDELAY, 0);
  158. /* Set default facility if none specified. */
  159. if ((pri & LOG_FACMASK) == 0)
  160. pri |= LogFacility;
  161. /* Build the message. We know the starting part of the message can take
  162. * no longer than 64 characters plus length of the LogTag. So it's
  163. * safe to test only LogTag and use normal sprintf everywhere else.
  164. */
  165. (void)time(&now);
  166. stdp = p = tbuf + sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
  167. if (LogTag) {
  168. if (strlen(LogTag) < sizeof(tbuf) - 64)
  169. p += sprintf(p, "%s", LogTag);
  170. else
  171. p += sprintf(p, "<BUFFER OVERRUN ATTEMPT>");
  172. }
  173. if (LogStat & LOG_PID)
  174. p += sprintf(p, "[%d]", getpid());
  175. if (LogTag) {
  176. *p++ = ':';
  177. *p++ = ' ';
  178. }
  179. head_end = p;
  180. /* We format the rest of the message. If the buffer becomes full, we mark
  181. * the message as truncated. Note that we require at least 2 free bytes
  182. * in the buffer as we might want to add "\r\n" there.
  183. */
  184. end = tbuf + sizeof(tbuf) - 1;
  185. __set_errno(saved_errno);
  186. p += vsnprintf(p, end - p, fmt, ap);
  187. if (p >= end || p < head_end) { /* Returned -1 in case of error... */
  188. static const char truncate_msg[12] = "[truncated] ";
  189. memmove(head_end + sizeof(truncate_msg), head_end,
  190. end - head_end - sizeof(truncate_msg));
  191. memcpy(head_end, truncate_msg, sizeof(truncate_msg));
  192. if (p < head_end) {
  193. while (p < end && *p) {
  194. p++;
  195. }
  196. }
  197. else {
  198. p = end - 1;
  199. }
  200. }
  201. last_chr = p;
  202. /* Output to stderr if requested. */
  203. if (LogStat & LOG_PERROR) {
  204. *last_chr = '\n';
  205. (void)write(STDERR_FILENO, stdp, last_chr - stdp + 1);
  206. }
  207. /* Output the message to the local logger using NUL as a message delimiter. */
  208. p = tbuf;
  209. *last_chr = 0;
  210. do {
  211. rc = write(LogFile, p, last_chr + 1 - p);
  212. if (rc < 0) {
  213. if ((errno==EAGAIN) || (errno==EINTR))
  214. rc=0;
  215. else {
  216. closelog_intern(0);
  217. break;
  218. }
  219. }
  220. p+=rc;
  221. } while (p <= last_chr);
  222. if (rc >= 0)
  223. goto getout;
  224. /*
  225. * Output the message to the console; don't worry about blocking,
  226. * if console blocks everything will. Make sure the error reported
  227. * is the one from the syslogd failure.
  228. */
  229. /* should mode be `O_WRONLY | O_NOCTTY' ? -- Uli */
  230. if (LogStat & LOG_CONS &&
  231. (fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
  232. p = index(tbuf, '>') + 1;
  233. last_chr[0] = '\r';
  234. last_chr[1] = '\n';
  235. (void)write(fd, p, last_chr - p + 2);
  236. (void)close(fd);
  237. }
  238. getout:
  239. UNLOCK;
  240. if (sigpipe == 0)
  241. sigaction (SIGPIPE, &oldaction,
  242. (struct sigaction *) NULL);
  243. }
  244. /*
  245. * OPENLOG -- open system log
  246. */
  247. void
  248. openlog( const char *ident, int logstat, int logfac )
  249. {
  250. int logType = SOCK_DGRAM;
  251. LOCK;
  252. if (ident != NULL)
  253. LogTag = ident;
  254. LogStat = logstat;
  255. if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
  256. LogFacility = logfac;
  257. if (LogFile == -1) {
  258. SyslogAddr.sa_family = AF_UNIX;
  259. (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
  260. sizeof(SyslogAddr.sa_data));
  261. retry:
  262. if (LogStat & LOG_NDELAY) {
  263. if ((LogFile = socket(AF_UNIX, logType, 0)) == -1){
  264. UNLOCK;
  265. return;
  266. }
  267. /* fcntl(LogFile, F_SETFD, 1); */
  268. }
  269. }
  270. if (LogFile != -1 && !connected) {
  271. if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr) -
  272. sizeof(SyslogAddr.sa_data) + strlen(SyslogAddr.sa_data)) != -1)
  273. {
  274. connected = 1;
  275. } else if (logType == SOCK_DGRAM) {
  276. logType = SOCK_STREAM;
  277. if (LogFile != -1) {
  278. close(LogFile);
  279. LogFile = -1;
  280. }
  281. goto retry;
  282. } else {
  283. if (LogFile != -1) {
  284. close(LogFile);
  285. LogFile = -1;
  286. }
  287. }
  288. }
  289. UNLOCK;
  290. }
  291. /*
  292. * CLOSELOG -- close the system log
  293. */
  294. void
  295. closelog( void )
  296. {
  297. closelog_intern(1);
  298. }
  299. /* setlogmask -- set the log mask level */
  300. int setlogmask(int pmask)
  301. {
  302. int omask;
  303. omask = LogMask;
  304. LOCK;
  305. if (pmask != 0)
  306. LogMask = pmask;
  307. UNLOCK;
  308. return (omask);
  309. }