syslog.c 9.4 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. #include <features.h>
  35. /*
  36. * SYSLOG -- print message on log file
  37. *
  38. * This routine looks a lot like printf, except that it outputs to the
  39. * log file instead of the standard output. Also:
  40. * adds a timestamp,
  41. * prints the module name in front of the message,
  42. * has some other formatting types (or will sometime),
  43. * adds a newline on the end of the message.
  44. *
  45. * The output of this routine is intended to be read by syslogd(8).
  46. *
  47. * Author: Eric Allman
  48. * Modified to use UNIX domain IPC by Ralph Campbell
  49. * Patched March 12, 1996 by A. Ian Vogelesang <vogelesang@hdshq.com>
  50. * - to correct the handling of message & format string truncation,
  51. * - to visibly tag truncated records to facilitate
  52. * investigation of such Bad Things with grep, and,
  53. * - to correct the handling of case where "write"
  54. * returns after writing only part of the message.
  55. * Rewritten by Martin Mares <mj@atrey.karlin.mff.cuni.cz> on May 14, 1997
  56. * - better buffer overrun checks.
  57. * - special handling of "%m" removed as we use GNU sprintf which handles
  58. * it automatically.
  59. * - Major code cleanup.
  60. */
  61. #include <sys/types.h>
  62. #include <sys/socket.h>
  63. #include <sys/file.h>
  64. #include <sys/signal.h>
  65. #include <sys/syslog.h>
  66. #if 0
  67. #include "syslog.h"
  68. #include "pathnames.h"
  69. #endif
  70. #include <sys/uio.h>
  71. #include <sys/wait.h>
  72. #include <netdb.h>
  73. #include <string.h>
  74. #include <time.h>
  75. #include <unistd.h>
  76. #include <errno.h>
  77. #include <stdarg.h>
  78. #include <paths.h>
  79. #include <stdio.h>
  80. #include <ctype.h>
  81. #include <signal.h>
  82. #if defined(_REENTRENT) || defined(_THREAD_SAFE)
  83. # include <pthread.h>
  84. extern int __writev( int, const struct iovec *, size_t);
  85. /* We need to initialize the mutex. For this we use a method provided
  86. by pthread function 'pthread_once'. For this we need a once block. */
  87. static pthread_once__t _once_block = pthread_once_init;
  88. /* This is the mutex which protects the global environment of simultaneous
  89. modifications. */
  90. static pthread_mutex_t _syslog_mutex;
  91. static void
  92. DEFUN_VOID(_init_syslog_mutex)
  93. {
  94. pthread_mutex_init(&_syslog_mutex, pthread_mutexattr_default);
  95. }
  96. # define LOCK() \
  97. do { pthread_once(&_once_block, _init_syslog_mutex);
  98. pthread_mutex_lock(&_syslog_mutex); } while (0)
  99. # define UNLOCK() pthread_mutex_unlock(&_syslog_mutex)
  100. #else /* !_REENTRENT && !_THREAD_SAFE */
  101. # define LOCK()
  102. # define UNLOCK()
  103. #endif /* _REENTRENT || _THREAD_SAFE */
  104. static int LogFile = -1; /* fd for log */
  105. static int connected; /* have done connect */
  106. static int LogStat = 0; /* status bits, set by openlog() */
  107. static const char *LogTag = "syslog"; /* string to tag the entry with */
  108. static int LogFacility = LOG_USER; /* default facility code */
  109. static int LogMask = 0xff; /* mask of priorities to be logged */
  110. static void closelog_intern( int );
  111. void syslog( int, const char *, ...);
  112. void vsyslog( int, const char *, va_list );
  113. void openlog( const char *, int, int );
  114. void closelog( void );
  115. int setlogmask(int pmask);
  116. static void
  117. closelog_intern(int to_default)
  118. {
  119. LOCK();
  120. (void) close(LogFile);
  121. LogFile = -1;
  122. connected = 0;
  123. if (to_default)
  124. {
  125. LogStat = 0;
  126. LogTag = "syslog";
  127. LogFacility = LOG_USER;
  128. LogMask = 0xff;
  129. }
  130. UNLOCK();
  131. }
  132. static void
  133. sigpipe_handler (int sig)
  134. {
  135. closelog_intern (0);
  136. }
  137. /*
  138. * syslog, vsyslog --
  139. * print message on log file; output is intended for syslogd(8).
  140. */
  141. void
  142. syslog(int pri, const char *fmt, ...)
  143. {
  144. va_list ap;
  145. va_start(ap, fmt);
  146. vsyslog(pri, fmt, ap);
  147. va_end(ap);
  148. }
  149. void
  150. vsyslog( int pri, const char *fmt, va_list ap )
  151. {
  152. register char *p;
  153. char *last_chr, *head_end, *end, *stdp;
  154. time_t now;
  155. int fd, saved_errno;
  156. int rc;
  157. char tbuf[1024]; /* syslogd is unable to handle longer messages */
  158. struct sigaction action, oldaction;
  159. int sigpipe;
  160. memset (&action, 0, sizeof (action));
  161. action.sa_handler = sigpipe_handler;
  162. sigemptyset (&action.sa_mask);
  163. sigpipe = sigaction (SIGPIPE, &action, &oldaction);
  164. saved_errno = errno;
  165. LOCK();
  166. /* See if we should just throw out this message. */
  167. if (!(LogMask & LOG_MASK(LOG_PRI(pri))) || (pri &~ (LOG_PRIMASK|LOG_FACMASK)))
  168. goto getout;
  169. if (LogFile < 0 || !connected)
  170. openlog(LogTag, LogStat | LOG_NDELAY, 0);
  171. /* Set default facility if none specified. */
  172. if ((pri & LOG_FACMASK) == 0)
  173. pri |= LogFacility;
  174. /* Build the message. We know the starting part of the message can take
  175. * no longer than 64 characters plus length of the LogTag. So it's
  176. * safe to test only LogTag and use normal sprintf everywhere else.
  177. */
  178. (void)time(&now);
  179. stdp = p = tbuf + sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
  180. if (LogTag) {
  181. if (strlen(LogTag) < sizeof(tbuf) - 64)
  182. p += sprintf(p, "%s", LogTag);
  183. else
  184. p += sprintf(p, "<BUFFER OVERRUN ATTEMPT>");
  185. }
  186. if (LogStat & LOG_PID)
  187. p += sprintf(p, "[%d]", getpid());
  188. if (LogTag) {
  189. *p++ = ':';
  190. *p++ = ' ';
  191. }
  192. head_end = p;
  193. /* We format the rest of the message. If the buffer becomes full, we mark
  194. * the message as truncated. Note that we require at least 2 free bytes
  195. * in the buffer as we might want to add "\r\n" there.
  196. */
  197. end = tbuf + sizeof(tbuf) - 1;
  198. errno = saved_errno;
  199. p += vsnprintf(p, end - p, fmt, ap);
  200. if (p >= end || p < head_end) { /* Returned -1 in case of error... */
  201. static char truncate_msg[12] = "[truncated] ";
  202. memmove(head_end + sizeof(truncate_msg), head_end,
  203. end - head_end - sizeof(truncate_msg));
  204. memcpy(head_end, truncate_msg, sizeof(truncate_msg));
  205. p = end - 1;
  206. }
  207. last_chr = p;
  208. /* Output to stderr if requested. */
  209. if (LogStat & LOG_PERROR) {
  210. *last_chr = '\n';
  211. (void)write(STDERR_FILENO, stdp, last_chr - stdp + 1);
  212. }
  213. /* Output the message to the local logger using NUL as a message delimiter. */
  214. p = tbuf;
  215. *last_chr = 0;
  216. do {
  217. rc = write(LogFile, p, last_chr + 1 - p);
  218. if (rc < 0) {
  219. if ((errno==EAGAIN) || (errno==EINTR))
  220. rc=0;
  221. else {
  222. closelog_intern(0);
  223. break;
  224. }
  225. }
  226. p+=rc;
  227. } while (p <= last_chr);
  228. if (rc >= 0)
  229. goto getout;
  230. /*
  231. * Output the message to the console; don't worry about blocking,
  232. * if console blocks everything will. Make sure the error reported
  233. * is the one from the syslogd failure.
  234. */
  235. /* should mode be `O_WRONLY | O_NOCTTY' ? -- Uli */
  236. if (LogStat & LOG_CONS &&
  237. (fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
  238. p = index(tbuf, '>') + 1;
  239. last_chr[0] = '\r';
  240. last_chr[1] = '\n';
  241. (void)write(fd, p, last_chr - p + 2);
  242. (void)close(fd);
  243. }
  244. getout:
  245. UNLOCK();
  246. if (sigpipe == 0)
  247. sigaction (SIGPIPE, &oldaction,
  248. (struct sigaction *) NULL);
  249. }
  250. static struct sockaddr SyslogAddr; /* AF_UNIX address of local logger */
  251. /*
  252. * OPENLOG -- open system log
  253. */
  254. void
  255. openlog( const char *ident, int logstat, int logfac )
  256. {
  257. LOCK();
  258. if (ident != NULL)
  259. LogTag = ident;
  260. LogStat = logstat;
  261. if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
  262. LogFacility = logfac;
  263. if (LogFile == -1) {
  264. SyslogAddr.sa_family = AF_UNIX;
  265. (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
  266. sizeof(SyslogAddr.sa_data));
  267. if (LogStat & LOG_NDELAY) {
  268. if ((LogFile = socket(AF_UNIX, SOCK_STREAM, 0)) == -1){
  269. UNLOCK();
  270. return;
  271. }
  272. /* fcntl(LogFile, F_SETFD, 1); */
  273. }
  274. }
  275. if (LogFile != -1 && !connected &&
  276. #if 0
  277. connect(LogFile, &SyslogAddr, sizeof(SyslogAddr.sa_family)+
  278. strlen(SyslogAddr.sa_data)) != -1)
  279. #else
  280. connect(LogFile, &SyslogAddr, sizeof(SyslogAddr) -
  281. sizeof(SyslogAddr.sa_data) +
  282. strlen(SyslogAddr.sa_data)) != -1)
  283. #endif
  284. connected = 1;
  285. UNLOCK();
  286. }
  287. /*
  288. * CLOSELOG -- close the system log
  289. */
  290. void
  291. closelog( void )
  292. {
  293. closelog_intern(1);
  294. }
  295. /* setlogmask -- set the log mask level */
  296. int setlogmask(int pmask)
  297. {
  298. int omask;
  299. omask = LogMask;
  300. LOCK();
  301. if (pmask != 0)
  302. LogMask = pmask;
  303. UNLOCK();
  304. return (omask);
  305. }