syslog.c 8.8 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. /* Build the message. We know the starting part of the message can take
  159. * no longer than 64 characters plus length of the LogTag. So it's
  160. * safe to test only LogTag and use normal sprintf everywhere else.
  161. */
  162. (void)time(&now);
  163. stdp = p = tbuf + sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
  164. if (LogTag) {
  165. if (strlen(LogTag) < sizeof(tbuf) - 64)
  166. p += sprintf(p, "%s", LogTag);
  167. else
  168. p += sprintf(p, "<BUFFER OVERRUN ATTEMPT>");
  169. }
  170. if (LogStat & LOG_PID)
  171. p += sprintf(p, "[%d]", getpid());
  172. if (LogTag) {
  173. *p++ = ':';
  174. *p++ = ' ';
  175. }
  176. head_end = p;
  177. /* We format the rest of the message. If the buffer becomes full, we mark
  178. * the message as truncated. Note that we require at least 2 free bytes
  179. * in the buffer as we might want to add "\r\n" there.
  180. */
  181. end = tbuf + sizeof(tbuf) - 1;
  182. __set_errno(saved_errno);
  183. p += vsnprintf(p, end - p, fmt, ap);
  184. if (p >= end || p < head_end) { /* Returned -1 in case of error... */
  185. static const char truncate_msg[12] = "[truncated] ";
  186. memmove(head_end + sizeof(truncate_msg), head_end,
  187. end - head_end - sizeof(truncate_msg));
  188. memcpy(head_end, truncate_msg, sizeof(truncate_msg));
  189. p = end - 1;
  190. }
  191. last_chr = p;
  192. /* Output to stderr if requested. */
  193. if (LogStat & LOG_PERROR) {
  194. *last_chr = '\n';
  195. (void)write(STDERR_FILENO, stdp, last_chr - stdp + 1);
  196. }
  197. /* Output the message to the local logger using NUL as a message delimiter. */
  198. p = tbuf;
  199. *last_chr = 0;
  200. do {
  201. rc = write(LogFile, p, last_chr + 1 - p);
  202. if (rc < 0) {
  203. if ((errno==EAGAIN) || (errno==EINTR))
  204. rc=0;
  205. else {
  206. closelog_intern(0);
  207. break;
  208. }
  209. }
  210. p+=rc;
  211. } while (p <= last_chr);
  212. if (rc >= 0)
  213. goto getout;
  214. /*
  215. * Output the message to the console; don't worry about blocking,
  216. * if console blocks everything will. Make sure the error reported
  217. * is the one from the syslogd failure.
  218. */
  219. /* should mode be `O_WRONLY | O_NOCTTY' ? -- Uli */
  220. if (LogStat & LOG_CONS &&
  221. (fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) {
  222. p = index(tbuf, '>') + 1;
  223. last_chr[0] = '\r';
  224. last_chr[1] = '\n';
  225. (void)write(fd, p, last_chr - p + 2);
  226. (void)close(fd);
  227. }
  228. getout:
  229. UNLOCK;
  230. if (sigpipe == 0)
  231. sigaction (SIGPIPE, &oldaction,
  232. (struct sigaction *) NULL);
  233. }
  234. /*
  235. * OPENLOG -- open system log
  236. */
  237. void
  238. openlog( const char *ident, int logstat, int logfac )
  239. {
  240. int logType = SOCK_DGRAM;
  241. LOCK;
  242. if (ident != NULL)
  243. LogTag = ident;
  244. LogStat = logstat;
  245. if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
  246. LogFacility = logfac;
  247. if (LogFile == -1) {
  248. SyslogAddr.sa_family = AF_UNIX;
  249. (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
  250. sizeof(SyslogAddr.sa_data));
  251. retry:
  252. if (LogStat & LOG_NDELAY) {
  253. if ((LogFile = socket(AF_UNIX, logType, 0)) == -1){
  254. UNLOCK;
  255. return;
  256. }
  257. /* fcntl(LogFile, F_SETFD, 1); */
  258. }
  259. }
  260. if (LogFile != -1 && !connected) {
  261. if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr) -
  262. sizeof(SyslogAddr.sa_data) + strlen(SyslogAddr.sa_data)) != -1)
  263. {
  264. connected = 1;
  265. } else if (logType == SOCK_DGRAM) {
  266. logType = SOCK_STREAM;
  267. if (LogFile != -1) {
  268. close(LogFile);
  269. LogFile = -1;
  270. }
  271. goto retry;
  272. } else {
  273. if (LogFile != -1) {
  274. close(LogFile);
  275. LogFile = -1;
  276. }
  277. }
  278. }
  279. UNLOCK;
  280. }
  281. /*
  282. * CLOSELOG -- close the system log
  283. */
  284. void
  285. closelog( void )
  286. {
  287. closelog_intern(1);
  288. }
  289. /* setlogmask -- set the log mask level */
  290. int setlogmask(int pmask)
  291. {
  292. int omask;
  293. omask = LogMask;
  294. LOCK;
  295. if (pmask != 0)
  296. LogMask = pmask;
  297. UNLOCK;
  298. return (omask);
  299. }