1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1983, 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __SCCSID("@(#)syslog.c 8.5 (Berkeley) 4/29/95"); 34 #include "namespace.h" 35 #include <sys/param.h> 36 #include <sys/socket.h> 37 #include <sys/syslog.h> 38 #include <sys/time.h> 39 #include <sys/uio.h> 40 #include <sys/un.h> 41 #include <netdb.h> 42 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <paths.h> 46 #include <pthread.h> 47 #include <stdbool.h> 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <time.h> 52 #include <unistd.h> 53 54 #include <stdarg.h> 55 #include "un-namespace.h" 56 57 #include "libc_private.h" 58 59 /* Maximum number of characters of syslog message */ 60 #define MAXLINE 8192 61 62 static int LogFile = -1; /* fd for log */ 63 static bool connected; /* have done connect */ 64 static int opened; /* have done openlog() */ 65 static int LogStat = 0; /* status bits, set by openlog() */ 66 static pid_t LogPid = -1; /* process id to tag the entry with */ 67 static const char *LogTag = NULL; /* string to tag the entry with */ 68 static int LogTagLength = -1; /* usable part of LogTag */ 69 static int LogFacility = LOG_USER; /* default facility code */ 70 static int LogMask = 0xff; /* mask of priorities to be logged */ 71 static pthread_mutex_t syslog_mutex = PTHREAD_MUTEX_INITIALIZER; 72 73 #define THREAD_LOCK() \ 74 do { \ 75 if (__isthreaded) _pthread_mutex_lock(&syslog_mutex); \ 76 } while(0) 77 #define THREAD_UNLOCK() \ 78 do { \ 79 if (__isthreaded) _pthread_mutex_unlock(&syslog_mutex); \ 80 } while(0) 81 82 /* RFC5424 defined value. */ 83 #define NILVALUE "-" 84 85 static void disconnectlog(void); /* disconnect from syslogd */ 86 static void connectlog(void); /* (re)connect to syslogd */ 87 static void openlog_unlocked(const char *, int, int); 88 static void parse_tag(void); /* parse ident[NNN] if needed */ 89 90 /* 91 * Format of the magic cookie passed through the stdio hook 92 */ 93 struct bufcookie { 94 char *base; /* start of buffer */ 95 int left; 96 }; 97 98 /* 99 * stdio write hook for writing to a static string buffer 100 * XXX: Maybe one day, dynamically allocate it so that the line length 101 * is `unlimited'. 102 */ 103 static int 104 writehook(void *cookie, const char *buf, int len) 105 { 106 struct bufcookie *h; /* private `handle' */ 107 108 h = (struct bufcookie *)cookie; 109 if (len > h->left) { 110 /* clip in case of wraparound */ 111 len = h->left; 112 } 113 if (len > 0) { 114 (void)memcpy(h->base, buf, len); /* `write' it. */ 115 h->base += len; 116 h->left -= len; 117 } 118 return len; 119 } 120 121 /* 122 * syslog, vsyslog -- 123 * print message on log file; output is intended for syslogd(8). 124 */ 125 void 126 syslog(int pri, const char *fmt, ...) 127 { 128 va_list ap; 129 130 va_start(ap, fmt); 131 vsyslog(pri, fmt, ap); 132 va_end(ap); 133 } 134 135 static void 136 vsyslog1(int pri, const char *fmt, va_list ap) 137 { 138 struct timeval now; 139 struct tm tm; 140 char ch, *p; 141 long tz_offset; 142 int cnt, fd, saved_errno; 143 char hostname[MAXHOSTNAMELEN], *stdp, tbuf[MAXLINE], fmt_cpy[MAXLINE], 144 errstr[64], tz_sign; 145 FILE *fp, *fmt_fp; 146 struct bufcookie tbuf_cookie; 147 struct bufcookie fmt_cookie; 148 149 #define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID 150 /* Check for invalid bits. */ 151 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) { 152 syslog(INTERNALLOG, 153 "syslog: unknown facility/priority: %x", pri); 154 pri &= LOG_PRIMASK|LOG_FACMASK; 155 } 156 157 saved_errno = errno; 158 159 /* Check priority against setlogmask values. */ 160 if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) 161 return; 162 163 /* Set default facility if none specified. */ 164 if ((pri & LOG_FACMASK) == 0) 165 pri |= LogFacility; 166 167 /* Create the primary stdio hook */ 168 tbuf_cookie.base = tbuf; 169 tbuf_cookie.left = sizeof(tbuf); 170 fp = fwopen(&tbuf_cookie, writehook); 171 if (fp == NULL) 172 return; 173 174 /* Build the message according to RFC 5424. Tag and version. */ 175 (void)fprintf(fp, "<%d>1 ", pri); 176 /* Timestamp similar to RFC 3339. */ 177 if (gettimeofday(&now, NULL) == 0 && 178 localtime_r(&now.tv_sec, &tm) != NULL) { 179 if (tm.tm_gmtoff < 0) { 180 tz_sign = '-'; 181 tz_offset = -tm.tm_gmtoff; 182 } else { 183 tz_sign = '+'; 184 tz_offset = tm.tm_gmtoff; 185 } 186 187 (void)fprintf(fp, 188 "%04d-%02d-%02d" /* Date. */ 189 "T%02d:%02d:%02d.%06ld" /* Time. */ 190 "%c%02ld:%02ld ", /* Time zone offset. */ 191 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 192 tm.tm_hour, tm.tm_min, tm.tm_sec, now.tv_usec, 193 tz_sign, tz_offset / 3600, (tz_offset % 3600) / 60); 194 } else 195 (void)fputs(NILVALUE " ", fp); 196 /* Hostname. */ 197 (void)gethostname(hostname, sizeof(hostname)); 198 (void)fprintf(fp, "%s ", 199 hostname[0] == '\0' ? NILVALUE : hostname); 200 if (LogStat & LOG_PERROR) { 201 /* Transfer to string buffer */ 202 (void)fflush(fp); 203 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left); 204 } 205 /* Application name. */ 206 if (LogTag == NULL) 207 LogTag = _getprogname(); 208 else if (LogTagLength == -1) 209 parse_tag(); 210 if (LogTagLength > 0) 211 (void)fprintf(fp, "%.*s ", LogTagLength, LogTag); 212 else 213 (void)fprintf(fp, "%s ", LogTag == NULL ? NILVALUE : LogTag); 214 /* 215 * Provide the process ID regardless of whether LOG_PID has been 216 * specified, as it provides valuable information. Many 217 * applications tend not to use this, even though they should. 218 */ 219 if (LogTagLength <= 0) 220 LogPid = getpid(); 221 (void)fprintf(fp, "%d ", (int)LogPid); 222 /* Message ID. */ 223 (void)fputs(NILVALUE " ", fp); 224 /* Structured data. */ 225 (void)fputs(NILVALUE " ", fp); 226 227 /* Check to see if we can skip expanding the %m */ 228 if (strstr(fmt, "%m")) { 229 230 /* Create the second stdio hook */ 231 fmt_cookie.base = fmt_cpy; 232 fmt_cookie.left = sizeof(fmt_cpy) - 1; 233 fmt_fp = fwopen(&fmt_cookie, writehook); 234 if (fmt_fp == NULL) { 235 fclose(fp); 236 return; 237 } 238 239 /* 240 * Substitute error message for %m. Be careful not to 241 * molest an escaped percent "%%m". We want to pass it 242 * on untouched as the format is later parsed by vfprintf. 243 */ 244 for ( ; (ch = *fmt); ++fmt) { 245 if (ch == '%' && fmt[1] == 'm') { 246 ++fmt; 247 strerror_r(saved_errno, errstr, sizeof(errstr)); 248 fputs(errstr, fmt_fp); 249 } else if (ch == '%' && fmt[1] == '%') { 250 ++fmt; 251 fputc(ch, fmt_fp); 252 fputc(ch, fmt_fp); 253 } else { 254 fputc(ch, fmt_fp); 255 } 256 } 257 258 /* Null terminate if room */ 259 fputc(0, fmt_fp); 260 fclose(fmt_fp); 261 262 /* Guarantee null termination */ 263 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0'; 264 265 fmt = fmt_cpy; 266 } 267 268 /* Message. */ 269 (void)vfprintf(fp, fmt, ap); 270 (void)fclose(fp); 271 272 cnt = sizeof(tbuf) - tbuf_cookie.left; 273 274 /* Remove a trailing newline */ 275 if (tbuf[cnt - 1] == '\n') 276 cnt--; 277 278 /* Output to stderr if requested. */ 279 if (LogStat & LOG_PERROR) { 280 struct iovec iov[2]; 281 struct iovec *v = iov; 282 283 v->iov_base = stdp; 284 v->iov_len = cnt - (stdp - tbuf); 285 ++v; 286 v->iov_base = "\n"; 287 v->iov_len = 1; 288 (void)_writev(STDERR_FILENO, iov, 2); 289 } 290 291 /* Get connected, output the message to the local logger. */ 292 if (!opened) 293 openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0); 294 connectlog(); 295 296 /* 297 * If the send() failed, there are two likely scenarios: 298 * 1) syslogd was restarted. In this case make one (only) attempt 299 * to reconnect. 300 * 2) We filled our buffer due to syslogd not being able to read 301 * as fast as we write. In this case prefer to lose the current 302 * message rather than whole buffer of previously logged data. 303 */ 304 if (send(LogFile, tbuf, cnt, 0) < 0) { 305 if (errno != ENOBUFS) { 306 disconnectlog(); 307 connectlog(); 308 if (send(LogFile, tbuf, cnt, 0) >= 0) 309 return; 310 } 311 } else 312 return; 313 314 /* 315 * Output the message to the console; try not to block 316 * as a blocking console should not stop other processes. 317 * Make sure the error reported is the one from the syslogd failure. 318 */ 319 if (LogStat & LOG_CONS && 320 (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK|O_CLOEXEC, 0)) >= 321 0) { 322 struct iovec iov[2]; 323 struct iovec *v = iov; 324 325 p = strchr(tbuf, '>') + 3; 326 v->iov_base = p; 327 v->iov_len = cnt - (p - tbuf); 328 ++v; 329 v->iov_base = "\r\n"; 330 v->iov_len = 2; 331 (void)_writev(fd, iov, 2); 332 (void)_close(fd); 333 } 334 } 335 336 static void 337 syslog_cancel_cleanup(void *arg __unused) 338 { 339 340 THREAD_UNLOCK(); 341 } 342 343 void 344 vsyslog(int pri, const char *fmt, va_list ap) 345 { 346 347 THREAD_LOCK(); 348 pthread_cleanup_push(syslog_cancel_cleanup, NULL); 349 vsyslog1(pri, fmt, ap); 350 pthread_cleanup_pop(1); 351 } 352 353 /* Should be called with mutex acquired */ 354 static void 355 disconnectlog(void) 356 { 357 /* 358 * If the user closed the FD and opened another in the same slot, 359 * that's their problem. They should close it before calling on 360 * system services. 361 */ 362 if (LogFile != -1) { 363 _close(LogFile); 364 LogFile = -1; 365 } 366 connected = false; /* retry connect */ 367 } 368 369 /* Should be called with mutex acquired */ 370 static void 371 connectlog(void) 372 { 373 struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ 374 375 if (LogFile == -1) { 376 socklen_t len; 377 378 if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 379 0)) == -1) 380 return; 381 if (_getsockopt(LogFile, SOL_SOCKET, SO_SNDBUF, &len, 382 &(socklen_t){sizeof(len)}) == 0) { 383 if (len < MAXLINE) { 384 len = MAXLINE; 385 (void)_setsockopt(LogFile, SOL_SOCKET, SO_SNDBUF, 386 &len, sizeof(len)); 387 } 388 } 389 } 390 if (!connected) { 391 SyslogAddr.sun_len = sizeof(SyslogAddr); 392 SyslogAddr.sun_family = AF_UNIX; 393 394 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, 395 sizeof SyslogAddr.sun_path); 396 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 397 sizeof(SyslogAddr)) != -1) 398 connected = true; 399 else { 400 (void)_close(LogFile); 401 LogFile = -1; 402 } 403 } 404 } 405 406 static void 407 openlog_unlocked(const char *ident, int logstat, int logfac) 408 { 409 if (ident != NULL) { 410 LogTag = ident; 411 LogTagLength = -1; 412 } 413 LogStat = logstat; 414 parse_tag(); 415 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) 416 LogFacility = logfac; 417 418 if (LogStat & LOG_NDELAY) /* open immediately */ 419 connectlog(); 420 421 opened = 1; /* ident and facility has been set */ 422 } 423 424 void 425 openlog(const char *ident, int logstat, int logfac) 426 { 427 428 THREAD_LOCK(); 429 pthread_cleanup_push(syslog_cancel_cleanup, NULL); 430 openlog_unlocked(ident, logstat, logfac); 431 pthread_cleanup_pop(1); 432 } 433 434 435 void 436 closelog(void) 437 { 438 THREAD_LOCK(); 439 if (LogFile != -1) { 440 (void)_close(LogFile); 441 LogFile = -1; 442 } 443 LogTag = NULL; 444 LogTagLength = -1; 445 connected = false; 446 THREAD_UNLOCK(); 447 } 448 449 /* setlogmask -- set the log mask level */ 450 int 451 setlogmask(int pmask) 452 { 453 int omask; 454 455 THREAD_LOCK(); 456 omask = LogMask; 457 if (pmask != 0) 458 LogMask = pmask; 459 THREAD_UNLOCK(); 460 return (omask); 461 } 462 463 /* 464 * Obtain LogPid from LogTag formatted as per RFC 3164, 465 * Section 5.3 Originating Process Information: 466 * 467 * ident[NNN] 468 */ 469 static void 470 parse_tag(void) 471 { 472 char *begin, *end, *p; 473 pid_t pid; 474 475 if (LogTag == NULL || (LogStat & LOG_PID) != 0) 476 return; 477 /* 478 * LogTagLength is -1 if LogTag was not parsed yet. 479 * Avoid multiple passes over same LogTag. 480 */ 481 LogTagLength = 0; 482 483 /* Check for presence of opening [ and non-empty ident. */ 484 if ((begin = strchr(LogTag, '[')) == NULL || begin == LogTag) 485 return; 486 /* Check for presence of closing ] at the very end and non-empty pid. */ 487 if ((end = strchr(begin + 1, ']')) == NULL || end[1] != 0 || 488 (end - begin) < 2) 489 return; 490 491 /* Check for pid to contain digits only. */ 492 pid = (pid_t)strtol(begin + 1, &p, 10); 493 if (p != end) 494 return; 495 496 LogPid = pid; 497 LogTagLength = begin - LogTag; 498 } 499