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 #if defined(LIBC_SCCS) && !defined(lint) 35 static char sccsid[] = "@(#)syslog.c 8.5 (Berkeley) 4/29/95"; 36 #endif /* LIBC_SCCS and not lint */ 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "namespace.h" 41 #include <sys/types.h> 42 #include <sys/socket.h> 43 #include <sys/syslog.h> 44 #include <sys/uio.h> 45 #include <sys/un.h> 46 #include <netdb.h> 47 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <paths.h> 51 #include <pthread.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <time.h> 56 #include <unistd.h> 57 58 #include <stdarg.h> 59 #include "un-namespace.h" 60 61 #include "libc_private.h" 62 63 static int LogFile = -1; /* fd for log */ 64 static int status; /* connection status */ 65 static int opened; /* have done openlog() */ 66 static int LogStat = 0; /* status bits, set by openlog() */ 67 static const char *LogTag = NULL; /* string to tag the entry with */ 68 static int LogFacility = LOG_USER; /* default facility code */ 69 static int LogMask = 0xff; /* mask of priorities to be logged */ 70 static pthread_mutex_t syslog_mutex = PTHREAD_MUTEX_INITIALIZER; 71 72 #define THREAD_LOCK() \ 73 do { \ 74 if (__isthreaded) _pthread_mutex_lock(&syslog_mutex); \ 75 } while(0) 76 #define THREAD_UNLOCK() \ 77 do { \ 78 if (__isthreaded) _pthread_mutex_unlock(&syslog_mutex); \ 79 } while(0) 80 81 static void disconnectlog(void); /* disconnect from syslogd */ 82 static void connectlog(void); /* (re)connect to syslogd */ 83 static void openlog_unlocked(const char *, int, int); 84 85 enum { 86 NOCONN = 0, 87 CONNDEF, 88 CONNPRIV, 89 }; 90 91 /* 92 * Format of the magic cookie passed through the stdio hook 93 */ 94 struct bufcookie { 95 char *base; /* start of buffer */ 96 int left; 97 }; 98 99 /* 100 * stdio write hook for writing to a static string buffer 101 * XXX: Maybe one day, dynamically allocate it so that the line length 102 * is `unlimited'. 103 */ 104 static int 105 writehook(void *cookie, const char *buf, int len) 106 { 107 struct bufcookie *h; /* private `handle' */ 108 109 h = (struct bufcookie *)cookie; 110 if (len > h->left) { 111 /* clip in case of wraparound */ 112 len = h->left; 113 } 114 if (len > 0) { 115 (void)memcpy(h->base, buf, len); /* `write' it. */ 116 h->base += len; 117 h->left -= len; 118 } 119 return 0; 120 } 121 122 /* 123 * syslog, vsyslog -- 124 * print message on log file; output is intended for syslogd(8). 125 */ 126 void 127 syslog(int pri, const char *fmt, ...) 128 { 129 va_list ap; 130 131 va_start(ap, fmt); 132 vsyslog(pri, fmt, ap); 133 va_end(ap); 134 } 135 136 void 137 vsyslog(int pri, const char *fmt, va_list ap) 138 { 139 int cnt; 140 char ch, *p; 141 time_t now; 142 int fd, saved_errno; 143 char *stdp, tbuf[2048], fmt_cpy[1024], timbuf[26], errstr[64]; 144 FILE *fp, *fmt_fp; 145 struct bufcookie tbuf_cookie; 146 struct bufcookie fmt_cookie; 147 148 #define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID 149 /* Check for invalid bits. */ 150 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) { 151 syslog(INTERNALLOG, 152 "syslog: unknown facility/priority: %x", pri); 153 pri &= LOG_PRIMASK|LOG_FACMASK; 154 } 155 156 THREAD_LOCK(); 157 158 /* Check priority against setlogmask values. */ 159 if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) { 160 THREAD_UNLOCK(); 161 return; 162 } 163 164 saved_errno = errno; 165 166 /* Set default facility if none specified. */ 167 if ((pri & LOG_FACMASK) == 0) 168 pri |= LogFacility; 169 170 /* Create the primary stdio hook */ 171 tbuf_cookie.base = tbuf; 172 tbuf_cookie.left = sizeof(tbuf); 173 fp = fwopen(&tbuf_cookie, writehook); 174 if (fp == NULL) { 175 THREAD_UNLOCK(); 176 return; 177 } 178 179 /* Build the message. */ 180 (void)time(&now); 181 (void)fprintf(fp, "<%d>", pri); 182 (void)fprintf(fp, "%.15s ", ctime_r(&now, timbuf) + 4); 183 if (LogStat & LOG_PERROR) { 184 /* Transfer to string buffer */ 185 (void)fflush(fp); 186 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left); 187 } 188 if (LogTag == NULL) 189 LogTag = _getprogname(); 190 if (LogTag != NULL) 191 (void)fprintf(fp, "%s", LogTag); 192 if (LogStat & LOG_PID) 193 (void)fprintf(fp, "[%d]", getpid()); 194 if (LogTag != NULL) { 195 (void)fprintf(fp, ": "); 196 } 197 198 /* Check to see if we can skip expanding the %m */ 199 if (strstr(fmt, "%m")) { 200 201 /* Create the second stdio hook */ 202 fmt_cookie.base = fmt_cpy; 203 fmt_cookie.left = sizeof(fmt_cpy) - 1; 204 fmt_fp = fwopen(&fmt_cookie, writehook); 205 if (fmt_fp == NULL) { 206 fclose(fp); 207 THREAD_UNLOCK(); 208 return; 209 } 210 211 /* 212 * Substitute error message for %m. Be careful not to 213 * molest an escaped percent "%%m". We want to pass it 214 * on untouched as the format is later parsed by vfprintf. 215 */ 216 for ( ; (ch = *fmt); ++fmt) { 217 if (ch == '%' && fmt[1] == 'm') { 218 ++fmt; 219 strerror_r(saved_errno, errstr, sizeof(errstr)); 220 fputs(errstr, fmt_fp); 221 } else if (ch == '%' && fmt[1] == '%') { 222 ++fmt; 223 fputc(ch, fmt_fp); 224 fputc(ch, fmt_fp); 225 } else { 226 fputc(ch, fmt_fp); 227 } 228 } 229 230 /* Null terminate if room */ 231 fputc(0, fmt_fp); 232 fclose(fmt_fp); 233 234 /* Guarantee null termination */ 235 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0'; 236 237 fmt = fmt_cpy; 238 } 239 240 (void)vfprintf(fp, fmt, ap); 241 (void)fclose(fp); 242 243 cnt = sizeof(tbuf) - tbuf_cookie.left; 244 245 /* Remove a trailing newline */ 246 if (tbuf[cnt - 1] == '\n') 247 cnt--; 248 249 /* Output to stderr if requested. */ 250 if (LogStat & LOG_PERROR) { 251 struct iovec iov[2]; 252 struct iovec *v = iov; 253 254 v->iov_base = stdp; 255 v->iov_len = cnt - (stdp - tbuf); 256 ++v; 257 v->iov_base = "\n"; 258 v->iov_len = 1; 259 (void)_writev(STDERR_FILENO, iov, 2); 260 } 261 262 /* Get connected, output the message to the local logger. */ 263 if (!opened) 264 openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0); 265 connectlog(); 266 267 /* 268 * If the send() failed, there are two likely scenarios: 269 * 1) syslogd was restarted 270 * 2) /var/run/log is out of socket buffer space, which 271 * in most cases means local DoS. 272 * We attempt to reconnect to /var/run/log to take care of 273 * case #1 and keep send()ing data to cover case #2 274 * to give syslogd a chance to empty its socket buffer. 275 * 276 * If we are working with a priveleged socket, then take 277 * only one attempt, because we don't want to freeze a 278 * critical application like su(1) or sshd(8). 279 * 280 */ 281 282 if (send(LogFile, tbuf, cnt, 0) < 0) { 283 if (errno != ENOBUFS) { 284 disconnectlog(); 285 connectlog(); 286 } 287 do { 288 _usleep(1); 289 if (send(LogFile, tbuf, cnt, 0) >= 0) { 290 THREAD_UNLOCK(); 291 return; 292 } 293 if (status == CONNPRIV) 294 break; 295 } while (errno == ENOBUFS); 296 } else { 297 THREAD_UNLOCK(); 298 return; 299 } 300 301 /* 302 * Output the message to the console; try not to block 303 * as a blocking console should not stop other processes. 304 * Make sure the error reported is the one from the syslogd failure. 305 */ 306 if (LogStat & LOG_CONS && 307 (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK, 0)) >= 0) { 308 struct iovec iov[2]; 309 struct iovec *v = iov; 310 311 p = strchr(tbuf, '>') + 1; 312 v->iov_base = p; 313 v->iov_len = cnt - (p - tbuf); 314 ++v; 315 v->iov_base = "\r\n"; 316 v->iov_len = 2; 317 (void)_writev(fd, iov, 2); 318 (void)_close(fd); 319 } 320 321 THREAD_UNLOCK(); 322 } 323 324 /* Should be called with mutex acquired */ 325 static void 326 disconnectlog(void) 327 { 328 /* 329 * If the user closed the FD and opened another in the same slot, 330 * that's their problem. They should close it before calling on 331 * system services. 332 */ 333 if (LogFile != -1) { 334 _close(LogFile); 335 LogFile = -1; 336 } 337 status = NOCONN; /* retry connect */ 338 } 339 340 /* Should be called with mutex acquired */ 341 static void 342 connectlog(void) 343 { 344 struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ 345 346 if (LogFile == -1) { 347 if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) 348 return; 349 (void)_fcntl(LogFile, F_SETFD, 1); 350 } 351 if (LogFile != -1 && status == NOCONN) { 352 SyslogAddr.sun_len = sizeof(SyslogAddr); 353 SyslogAddr.sun_family = AF_UNIX; 354 355 /* 356 * First try priveleged socket. If no success, 357 * then try default socket. 358 */ 359 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG_PRIV, 360 sizeof SyslogAddr.sun_path); 361 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 362 sizeof(SyslogAddr)) != -1) 363 status = CONNPRIV; 364 365 if (status == NOCONN) { 366 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, 367 sizeof SyslogAddr.sun_path); 368 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 369 sizeof(SyslogAddr)) != -1) 370 status = CONNDEF; 371 } 372 373 if (status == NOCONN) { 374 /* 375 * Try the old "/dev/log" path, for backward 376 * compatibility. 377 */ 378 (void)strncpy(SyslogAddr.sun_path, _PATH_OLDLOG, 379 sizeof SyslogAddr.sun_path); 380 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 381 sizeof(SyslogAddr)) != -1) 382 status = CONNDEF; 383 } 384 385 if (status == NOCONN) { 386 (void)_close(LogFile); 387 LogFile = -1; 388 } 389 } 390 } 391 392 static void 393 openlog_unlocked(const char *ident, int logstat, int logfac) 394 { 395 if (ident != NULL) 396 LogTag = ident; 397 LogStat = logstat; 398 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) 399 LogFacility = logfac; 400 401 if (LogStat & LOG_NDELAY) /* open immediately */ 402 connectlog(); 403 404 opened = 1; /* ident and facility has been set */ 405 } 406 407 void 408 openlog(const char *ident, int logstat, int logfac) 409 { 410 THREAD_LOCK(); 411 openlog_unlocked(ident, logstat, logfac); 412 THREAD_UNLOCK(); 413 } 414 415 416 void 417 closelog(void) 418 { 419 THREAD_LOCK(); 420 (void)_close(LogFile); 421 LogFile = -1; 422 LogTag = NULL; 423 status = NOCONN; 424 THREAD_UNLOCK(); 425 } 426 427 /* setlogmask -- set the log mask level */ 428 int 429 setlogmask(int pmask) 430 { 431 int omask; 432 433 THREAD_LOCK(); 434 omask = LogMask; 435 if (pmask != 0) 436 LogMask = pmask; 437 THREAD_UNLOCK(); 438 return (omask); 439 } 440