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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)syslog.c 8.5 (Berkeley) 4/29/95 30 * $FreeBSD: src/lib/libc/gen/syslog.c,v 1.39 2007/01/09 00:27:55 imp Exp $ 31 * $DragonFly: src/lib/libc/gen/syslog.c,v 1.9 2005/11/19 22:32:53 swildner Exp $ 32 */ 33 34 #include "namespace.h" 35 #include <sys/types.h> 36 #include <sys/socket.h> 37 #include <sys/syslog.h> 38 #include <sys/uio.h> 39 #include <sys/un.h> 40 #include <netdb.h> 41 42 #include <errno.h> 43 #include <fcntl.h> 44 #include <paths.h> 45 #include <pthread.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <time.h> 50 #include <unistd.h> 51 52 #include <stdarg.h> 53 #include "un-namespace.h" 54 55 #include "libc_private.h" 56 57 static int LogFile = -1; /* fd for log */ 58 static int status; /* connection status */ 59 static int opened; /* have done openlog() */ 60 static int LogStat = 0; /* status bits, set by openlog() */ 61 static const char *LogTag = NULL; /* string to tag the entry with */ 62 static int LogFacility = LOG_USER; /* default facility code */ 63 static int LogMask = 0xff; /* mask of priorities to be logged */ 64 static pthread_mutex_t syslog_mutex = PTHREAD_MUTEX_INITIALIZER; 65 66 #define THREAD_LOCK() \ 67 do { \ 68 if (__isthreaded) _pthread_mutex_lock(&syslog_mutex); \ 69 } while(0) 70 #define THREAD_UNLOCK() \ 71 do { \ 72 if (__isthreaded) _pthread_mutex_unlock(&syslog_mutex); \ 73 } while(0) 74 75 static void disconnectlog(void); /* disconnect from syslogd */ 76 static void connectlog(void); /* (re)connect to syslogd */ 77 static void openlog_unlocked(const char *, int, int); 78 79 enum { 80 NOCONN = 0, 81 CONNDEF, 82 CONNPRIV, 83 }; 84 85 /* 86 * Format of the magic cookie passed through the stdio hook 87 */ 88 struct bufcookie { 89 char *base; /* start of buffer */ 90 int left; 91 }; 92 93 /* 94 * stdio write hook for writing to a static string buffer 95 * XXX: Maybe one day, dynamically allocate it so that the line length 96 * is `unlimited'. 97 */ 98 static int 99 writehook(void *cookie, const char *buf, int len) 100 { 101 struct bufcookie *h; /* private `handle' */ 102 103 h = (struct bufcookie *)cookie; 104 if (len > h->left) { 105 /* clip in case of wraparound */ 106 len = h->left; 107 } 108 if (len > 0) { 109 memcpy(h->base, buf, len); /* `write' it. */ 110 h->base += len; 111 h->left -= len; 112 } 113 return len; 114 } 115 116 /* 117 * syslog, vsyslog -- 118 * print message on log file; output is intended for syslogd(8). 119 */ 120 void 121 syslog(int pri, const char *fmt, ...) 122 { 123 va_list ap; 124 125 va_start(ap, fmt); 126 vsyslog(pri, fmt, ap); 127 va_end(ap); 128 } 129 130 void 131 vsyslog(int pri, const char *fmt, va_list ap) 132 { 133 int cnt; 134 char ch, *p; 135 time_t now; 136 int fd, saved_errno; 137 char *stdp, tbuf[2048], fmt_cpy[1024], timbuf[26], errstr[64]; 138 FILE *fp, *fmt_fp; 139 struct bufcookie tbuf_cookie; 140 struct bufcookie fmt_cookie; 141 142 stdp = NULL; 143 144 #define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID 145 /* Check for invalid bits. */ 146 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) { 147 syslog(INTERNALLOG, 148 "syslog: unknown facility/priority: %x", pri); 149 pri &= LOG_PRIMASK|LOG_FACMASK; 150 } 151 152 saved_errno = errno; 153 154 THREAD_LOCK(); 155 156 /* Check priority against setlogmask values. */ 157 if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) { 158 THREAD_UNLOCK(); 159 return; 160 } 161 162 /* Set default facility if none specified. */ 163 if ((pri & LOG_FACMASK) == 0) 164 pri |= LogFacility; 165 166 /* Create the primary stdio hook */ 167 tbuf_cookie.base = tbuf; 168 tbuf_cookie.left = sizeof(tbuf); 169 fp = fwopen(&tbuf_cookie, writehook); 170 if (fp == NULL) { 171 THREAD_UNLOCK(); 172 return; 173 } 174 175 /* Build the message. */ 176 time(&now); 177 fprintf(fp, "<%d>", pri); 178 fprintf(fp, "%.15s ", ctime_r(&now, timbuf) + 4); 179 if (LogStat & LOG_PERROR) { 180 /* Transfer to string buffer */ 181 fflush(fp); 182 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left); 183 } 184 if (LogTag == NULL) 185 LogTag = _getprogname(); 186 if (LogTag != NULL) 187 fprintf(fp, "%s", LogTag); 188 if (LogStat & LOG_PID) 189 fprintf(fp, "[%d]", getpid()); 190 if (LogTag != NULL) { 191 fprintf(fp, ": "); 192 } 193 194 /* Check to see if we can skip expanding the %m */ 195 if (strstr(fmt, "%m")) { 196 197 /* Create the second stdio hook */ 198 fmt_cookie.base = fmt_cpy; 199 fmt_cookie.left = sizeof(fmt_cpy) - 1; 200 fmt_fp = fwopen(&fmt_cookie, writehook); 201 if (fmt_fp == NULL) { 202 fclose(fp); 203 THREAD_UNLOCK(); 204 return; 205 } 206 207 /* 208 * Substitute error message for %m. Be careful not to 209 * molest an escaped percent "%%m". We want to pass it 210 * on untouched as the format is later parsed by vfprintf. 211 */ 212 for ( ; (ch = *fmt); ++fmt) { 213 if (ch == '%' && fmt[1] == 'm') { 214 ++fmt; 215 strerror_r(saved_errno, errstr, sizeof(errstr)); 216 fputs(errstr, fmt_fp); 217 } else if (ch == '%' && fmt[1] == '%') { 218 ++fmt; 219 fputc(ch, fmt_fp); 220 fputc(ch, fmt_fp); 221 } else { 222 fputc(ch, fmt_fp); 223 } 224 } 225 226 /* Null terminate if room */ 227 fputc(0, fmt_fp); 228 fclose(fmt_fp); 229 230 /* Guarantee null termination */ 231 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0'; 232 233 fmt = fmt_cpy; 234 } 235 236 vfprintf(fp, fmt, ap); 237 fclose(fp); 238 239 cnt = sizeof(tbuf) - tbuf_cookie.left; 240 241 /* Remove a trailing newline */ 242 if (tbuf[cnt - 1] == '\n') 243 cnt--; 244 245 /* Output to stderr if requested. */ 246 if (LogStat & LOG_PERROR) { 247 struct iovec iov[2]; 248 struct iovec *v = iov; 249 250 v->iov_base = stdp; 251 v->iov_len = cnt - (stdp - tbuf); 252 ++v; 253 v->iov_base = "\n"; 254 v->iov_len = 1; 255 _writev(STDERR_FILENO, iov, 2); 256 } 257 258 /* Get connected, output the message to the local logger. */ 259 if (!opened) 260 openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0); 261 connectlog(); 262 263 /* 264 * If the send() failed, there are two likely scenarios: 265 * 1) syslogd was restarted 266 * 2) /var/run/log is out of socket buffer space, which 267 * in most cases means local DoS. 268 * We attempt to reconnect to /var/run/log to take care of 269 * case #1 and keep send()ing data to cover case #2 270 * to give syslogd a chance to empty its socket buffer. 271 * 272 * If we are working with a priveleged socket, then take 273 * only one attempt, because we don't want to freeze a 274 * critical application like su(1) or sshd(8). 275 * 276 */ 277 278 if (send(LogFile, tbuf, cnt, 0) < 0) { 279 if (errno != ENOBUFS) { 280 disconnectlog(); 281 connectlog(); 282 } 283 do { 284 _usleep(1); 285 if (send(LogFile, tbuf, cnt, 0) >= 0) { 286 THREAD_UNLOCK(); 287 return; 288 } 289 if (status == CONNPRIV) 290 break; 291 } while (errno == ENOBUFS); 292 } else { 293 THREAD_UNLOCK(); 294 return; 295 } 296 297 /* 298 * Output the message to the console; try not to block 299 * as a blocking console should not stop other processes. 300 * Make sure the error reported is the one from the syslogd failure. 301 */ 302 if (LogStat & LOG_CONS && 303 (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK, 0)) >= 0) { 304 struct iovec iov[2]; 305 struct iovec *v = iov; 306 307 p = strchr(tbuf, '>') + 1; 308 v->iov_base = p; 309 v->iov_len = cnt - (p - tbuf); 310 ++v; 311 v->iov_base = "\r\n"; 312 v->iov_len = 2; 313 _writev(fd, iov, 2); 314 _close(fd); 315 } 316 317 THREAD_UNLOCK(); 318 } 319 320 /* Should be called with mutex acquired */ 321 static void 322 disconnectlog(void) 323 { 324 /* 325 * If the user closed the FD and opened another in the same slot, 326 * that's their problem. They should close it before calling on 327 * system services. 328 */ 329 if (LogFile != -1) { 330 _close(LogFile); 331 LogFile = -1; 332 } 333 status = NOCONN; /* retry connect */ 334 } 335 336 /* Should be called with mutex acquired */ 337 static void 338 connectlog(void) 339 { 340 struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ 341 342 if (LogFile == -1) { 343 if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) 344 return; 345 _fcntl(LogFile, F_SETFD, 1); 346 } 347 if (LogFile != -1 && status == NOCONN) { 348 SyslogAddr.sun_len = sizeof(SyslogAddr); 349 SyslogAddr.sun_family = AF_UNIX; 350 351 /* 352 * First try priveleged socket. If no success, 353 * then try default socket. 354 */ 355 strncpy(SyslogAddr.sun_path, _PATH_LOG_PRIV, 356 sizeof SyslogAddr.sun_path); 357 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 358 sizeof(SyslogAddr)) != -1) 359 status = CONNPRIV; 360 361 if (status == NOCONN) { 362 strncpy(SyslogAddr.sun_path, _PATH_LOG, 363 sizeof SyslogAddr.sun_path); 364 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 365 sizeof(SyslogAddr)) != -1) 366 status = CONNDEF; 367 } 368 369 if (status == NOCONN) { 370 /* 371 * Try the old "/dev/log" path, for backward 372 * compatibility. 373 */ 374 strncpy(SyslogAddr.sun_path, _PATH_OLDLOG, 375 sizeof SyslogAddr.sun_path); 376 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 377 sizeof(SyslogAddr)) != -1) 378 status = CONNDEF; 379 } 380 381 if (status == NOCONN) { 382 _close(LogFile); 383 LogFile = -1; 384 } 385 } 386 } 387 388 static void 389 openlog_unlocked(const char *ident, int logstat, int logfac) 390 { 391 if (ident != NULL) 392 LogTag = ident; 393 LogStat = logstat; 394 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) 395 LogFacility = logfac; 396 397 if (LogStat & LOG_NDELAY) /* open immediately */ 398 connectlog(); 399 400 opened = 1; /* ident and facility has been set */ 401 } 402 403 void 404 openlog(const char *ident, int logstat, int logfac) 405 { 406 THREAD_LOCK(); 407 openlog_unlocked(ident, logstat, logfac); 408 THREAD_UNLOCK(); 409 } 410 411 412 void 413 closelog(void) 414 { 415 THREAD_LOCK(); 416 _close(LogFile); 417 LogFile = -1; 418 LogTag = NULL; 419 status = NOCONN; 420 THREAD_UNLOCK(); 421 } 422 423 /* setlogmask -- set the log mask level */ 424 int 425 setlogmask(int pmask) 426 { 427 int omask; 428 429 THREAD_LOCK(); 430 omask = LogMask; 431 if (pmask != 0) 432 LogMask = pmask; 433 THREAD_UNLOCK(); 434 return (omask); 435 } 436