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