syslog.c 11 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. /*
  34. * SYSLOG -- print message on log file
  35. *
  36. * This routine looks a lot like printf, except that it outputs to the
  37. * log file instead of the standard output. Also:
  38. * adds a timestamp,
  39. * prints the module name in front of the message,
  40. * has some other formatting types (or will sometime),
  41. * adds a newline on the end of the message.
  42. *
  43. * The output of this routine is intended to be read by syslogd(8).
  44. *
  45. * Author: Eric Allman
  46. * Modified to use UNIX domain IPC by Ralph Campbell
  47. * Patched March 12, 1996 by A. Ian Vogelesang <vogelesang@hdshq.com>
  48. * - to correct the handling of message & format string truncation,
  49. * - to visibly tag truncated records to facilitate
  50. * investigation of such Bad Things with grep, and,
  51. * - to correct the handling of case where "write"
  52. * returns after writing only part of the message.
  53. * Rewritten by Martin Mares <mj@atrey.karlin.mff.cuni.cz> on May 14, 1997
  54. * - better buffer overrun checks.
  55. * - special handling of "%m" removed as we use GNU sprintf which handles
  56. * it automatically.
  57. * - Major code cleanup.
  58. */
  59. #define __FORCE_GLIBC
  60. #include <features.h>
  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. #include <sys/uio.h>
  67. #include <sys/wait.h>
  68. #include <netdb.h>
  69. #include <string.h>
  70. #include <time.h>
  71. #include <unistd.h>
  72. #include <errno.h>
  73. #include <stdarg.h>
  74. #include <paths.h>
  75. #include <stdio.h>
  76. #include <ctype.h>
  77. #include <signal.h>
  78. libc_hidden_proto(openlog)
  79. libc_hidden_proto(syslog)
  80. libc_hidden_proto(vsyslog)
  81. libc_hidden_proto(closelog)
  82. /* Experimentally off - libc_hidden_proto(memset) */
  83. /* Experimentally off - libc_hidden_proto(memcpy) */
  84. /* Experimentally off - libc_hidden_proto(memmove) */
  85. /* Experimentally off - libc_hidden_proto(strchr) */
  86. /* Experimentally off - libc_hidden_proto(strlen) */
  87. /* Experimentally off - libc_hidden_proto(strncpy) */
  88. libc_hidden_proto(open)
  89. libc_hidden_proto(fcntl)
  90. libc_hidden_proto(socket)
  91. libc_hidden_proto(close)
  92. libc_hidden_proto(write)
  93. libc_hidden_proto(getpid)
  94. libc_hidden_proto(ctime)
  95. libc_hidden_proto(sigaction)
  96. libc_hidden_proto(sigemptyset)
  97. libc_hidden_proto(connect)
  98. libc_hidden_proto(sprintf)
  99. libc_hidden_proto(vsnprintf)
  100. /* Experimentally off - libc_hidden_proto(time) */
  101. #include <bits/uClibc_mutex.h>
  102. __UCLIBC_MUTEX_STATIC(mylock, PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP);
  103. static int LogFile = -1; /* fd for log */
  104. static smalluint connected; /* have done connect */
  105. /* all bits in option argument for openlog() fit in 8 bits */
  106. static smalluint LogStat = 0; /* status bits, set by openlog() */
  107. static const char *LogTag = "syslog"; /* string to tag the entry with */
  108. /* this fits in 8 bits too (LOG_LOCAL7 = 23<<3 = 184),
  109. * but NB: LOG_FACMASK is bigger (= 0x03f8 = 127<<3) for some strange reason.
  110. * Oh well. */
  111. static int LogFacility = LOG_USER;/* default facility code */
  112. /* bits mask of priorities (eight prios - 8 bits is enough) */
  113. static smalluint LogMask = 0xff; /* mask of priorities to be logged */
  114. /* AF_UNIX address of local logger (we use struct sockaddr
  115. * instead of struct sockaddr_un since "/dev/log" is small enough) */
  116. static const struct sockaddr SyslogAddr = {
  117. .sa_family = AF_UNIX, /* sa_family_t (usually a short) */
  118. .sa_data = _PATH_LOG /* char [14] */
  119. };
  120. static void
  121. closelog_intern(int sig)
  122. {
  123. /* mylock must be held by the caller */
  124. if (LogFile != -1) {
  125. (void) close(LogFile);
  126. }
  127. LogFile = -1;
  128. connected = 0;
  129. if (sig == 0) { /* called from closelog()? - reset to defaults */
  130. LogStat = 0;
  131. LogTag = "syslog";
  132. LogFacility = LOG_USER;
  133. LogMask = 0xff;
  134. }
  135. }
  136. /*
  137. * OPENLOG -- open system log
  138. */
  139. void
  140. openlog(const char *ident, int logstat, int logfac)
  141. {
  142. int logType = SOCK_DGRAM;
  143. __UCLIBC_MUTEX_LOCK(mylock);
  144. if (ident != NULL)
  145. LogTag = ident;
  146. LogStat = logstat;
  147. if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
  148. LogFacility = logfac;
  149. if (LogFile == -1) {
  150. retry:
  151. if (LogStat & LOG_NDELAY) {
  152. if ((LogFile = socket(AF_UNIX, logType, 0)) == -1) {
  153. goto DONE;
  154. }
  155. fcntl(LogFile, F_SETFD, 1); /* 1 == FD_CLOEXEC */
  156. /* We don't want to block if e.g. syslogd is SIGSTOPed */
  157. fcntl(LogFile, F_SETFL, O_NONBLOCK | fcntl(LogFile, F_GETFL));
  158. }
  159. }
  160. if (LogFile != -1 && !connected) {
  161. if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) != -1) {
  162. connected = 1;
  163. } else {
  164. if (LogFile != -1) {
  165. close(LogFile);
  166. LogFile = -1;
  167. }
  168. if (logType == SOCK_DGRAM) {
  169. logType = SOCK_STREAM;
  170. goto retry;
  171. }
  172. }
  173. }
  174. DONE:
  175. __UCLIBC_MUTEX_UNLOCK(mylock);
  176. }
  177. libc_hidden_def(openlog)
  178. /*
  179. * syslog, vsyslog --
  180. * print message on log file; output is intended for syslogd(8).
  181. */
  182. void
  183. vsyslog(int pri, const char *fmt, va_list ap)
  184. {
  185. register char *p;
  186. char *last_chr, *head_end, *end, *stdp;
  187. time_t now;
  188. int fd, saved_errno;
  189. int rc;
  190. char tbuf[1024]; /* syslogd is unable to handle longer messages */
  191. struct sigaction action, oldaction;
  192. memset(&action, 0, sizeof(action));
  193. action.sa_handler = closelog_intern;
  194. sigemptyset(&action.sa_mask); /* TODO: memset already zeroed it out! */
  195. /* Only two errors are possible for sigaction:
  196. * EFAULT (bad address of &oldaction) and EINVAL (invalid signo)
  197. * none of which can happen here. */
  198. /*int sigpipe =*/ sigaction(SIGPIPE, &action, &oldaction);
  199. saved_errno = errno;
  200. __UCLIBC_MUTEX_LOCK(mylock);
  201. /* See if we should just throw out this message. */
  202. if (!(LogMask & LOG_MASK(LOG_PRI(pri))) || (pri &~ (LOG_PRIMASK|LOG_FACMASK)))
  203. goto getout;
  204. if (LogFile < 0 || !connected)
  205. openlog(LogTag, LogStat | LOG_NDELAY, 0);
  206. /* Set default facility if none specified. */
  207. if ((pri & LOG_FACMASK) == 0)
  208. pri |= LogFacility;
  209. /* Build the message. We know the starting part of the message can take
  210. * no longer than 64 characters plus length of the LogTag. So it's
  211. * safe to test only LogTag and use normal sprintf everywhere else.
  212. */
  213. (void)time(&now);
  214. stdp = p = tbuf + sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
  215. if (LogTag) {
  216. if (strlen(LogTag) < sizeof(tbuf) - 64)
  217. p += sprintf(p, "%s", LogTag);
  218. else
  219. p += sprintf(p, "<BUFFER OVERRUN ATTEMPT>");
  220. }
  221. if (LogStat & LOG_PID)
  222. p += sprintf(p, "[%d]", getpid());
  223. if (LogTag) {
  224. *p++ = ':';
  225. *p++ = ' ';
  226. }
  227. head_end = p;
  228. /* We format the rest of the message. If the buffer becomes full, we mark
  229. * the message as truncated. Note that we require at least 2 free bytes
  230. * in the buffer as we might want to add "\r\n" there.
  231. */
  232. end = tbuf + sizeof(tbuf) - 1;
  233. __set_errno(saved_errno);
  234. p += vsnprintf(p, end - p, fmt, ap);
  235. if (p >= end || p < head_end) { /* Returned -1 in case of error... */
  236. static const char truncate_msg[12] = "[truncated] "; /* no NUL! */
  237. memmove(head_end + sizeof(truncate_msg), head_end,
  238. end - head_end - sizeof(truncate_msg));
  239. memcpy(head_end, truncate_msg, sizeof(truncate_msg));
  240. if (p < head_end) {
  241. while (p < end && *p) {
  242. p++;
  243. }
  244. }
  245. else {
  246. p = end - 1;
  247. }
  248. }
  249. last_chr = p;
  250. /* Output to stderr if requested. */
  251. if (LogStat & LOG_PERROR) {
  252. *last_chr = '\n';
  253. (void)write(STDERR_FILENO, stdp, last_chr - stdp + 1);
  254. }
  255. /* Output the message to the local logger using NUL as a message delimiter. */
  256. p = tbuf;
  257. *last_chr = 0;
  258. if (LogFile >= 0) {
  259. do {
  260. rc = write(LogFile, p, last_chr + 1 - p);
  261. if (rc < 0) {
  262. /* I don't think looping forever on EAGAIN is a good idea.
  263. * Imagine that syslogd is SIGSTOPed... */
  264. if (/* (errno != EAGAIN) && */ (errno != EINTR)) {
  265. closelog_intern(1); /* 1: do not reset LogXXX globals to default */
  266. goto write_err;
  267. }
  268. rc = 0;
  269. }
  270. p += rc;
  271. } while (p <= last_chr);
  272. goto getout;
  273. }
  274. write_err:
  275. /*
  276. * Output the message to the console; don't worry about blocking,
  277. * if console blocks everything will. Make sure the error reported
  278. * is the one from the syslogd failure.
  279. */
  280. /* should mode be O_WRONLY | O_NOCTTY? -- Uli */
  281. /* yes, but in Linux "/dev/console" never becomes ctty anyway -- vda */
  282. if ((LogStat & LOG_CONS) &&
  283. (fd = open(_PATH_CONSOLE, O_WRONLY | O_NOCTTY)) >= 0) {
  284. p = strchr(tbuf, '>') + 1;
  285. last_chr[0] = '\r';
  286. last_chr[1] = '\n';
  287. (void)write(fd, p, last_chr - p + 2);
  288. (void)close(fd);
  289. }
  290. getout:
  291. __UCLIBC_MUTEX_UNLOCK(mylock);
  292. /*if (sigpipe == 0)*/
  293. sigaction(SIGPIPE, &oldaction, (struct sigaction *) NULL);
  294. }
  295. libc_hidden_def(vsyslog)
  296. void
  297. syslog(int pri, const char *fmt, ...)
  298. {
  299. va_list ap;
  300. va_start(ap, fmt);
  301. vsyslog(pri, fmt, ap);
  302. va_end(ap);
  303. }
  304. libc_hidden_def(syslog)
  305. /*
  306. * CLOSELOG -- close the system log
  307. */
  308. void
  309. closelog(void)
  310. {
  311. __UCLIBC_MUTEX_LOCK(mylock);
  312. closelog_intern(0); /* 0: reset LogXXX globals to default */
  313. __UCLIBC_MUTEX_UNLOCK(mylock);
  314. }
  315. libc_hidden_def(closelog)
  316. /* setlogmask -- set the log mask level */
  317. int setlogmask(int pmask)
  318. {
  319. int omask;
  320. omask = LogMask;
  321. if (pmask != 0) {
  322. __UCLIBC_MUTEX_LOCK(mylock);
  323. LogMask = pmask;
  324. __UCLIBC_MUTEX_UNLOCK(mylock);
  325. }
  326. return omask;
  327. }