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 __FBSDID("$FreeBSD$"); 35 36 #include "namespace.h" 37 #include <sys/param.h> 38 #include <sys/socket.h> 39 #include <sys/syslog.h> 40 #include <sys/time.h> 41 #include <sys/uio.h> 42 #include <sys/un.h> 43 #include <netdb.h> 44 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <paths.h> 48 #include <pthread.h> 49 #include <stdbool.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <time.h> 54 #include <unistd.h> 55 56 #include <stdarg.h> 57 #include "un-namespace.h" 58 59 #include "libc_private.h" 60 61 /* Maximum number of characters of syslog message */ 62 #define MAXLINE 8192 63 64 static int LogFile = -1; /* fd for log */ 65 static bool connected; /* have done connect */ 66 static int opened; /* have done openlog() */ 67 static int LogStat = 0; /* status bits, set by openlog() */ 68 static const char *LogTag = NULL; /* string to tag the entry with */ 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 89 /* 90 * Format of the magic cookie passed through the stdio hook 91 */ 92 struct bufcookie { 93 char *base; /* start of buffer */ 94 int left; 95 }; 96 97 /* 98 * stdio write hook for writing to a static string buffer 99 * XXX: Maybe one day, dynamically allocate it so that the line length 100 * is `unlimited'. 101 */ 102 static int 103 writehook(void *cookie, const char *buf, int len) 104 { 105 struct bufcookie *h; /* private `handle' */ 106 107 h = (struct bufcookie *)cookie; 108 if (len > h->left) { 109 /* clip in case of wraparound */ 110 len = h->left; 111 } 112 if (len > 0) { 113 (void)memcpy(h->base, buf, len); /* `write' it. */ 114 h->base += len; 115 h->left -= len; 116 } 117 return len; 118 } 119 120 /* 121 * syslog, vsyslog -- 122 * print message on log file; output is intended for syslogd(8). 123 */ 124 void 125 syslog(int pri, const char *fmt, ...) 126 { 127 va_list ap; 128 129 va_start(ap, fmt); 130 vsyslog(pri, fmt, ap); 131 va_end(ap); 132 } 133 134 static void 135 vsyslog1(int pri, const char *fmt, va_list ap) 136 { 137 struct timeval now; 138 struct tm tm; 139 char ch, *p; 140 long tz_offset; 141 int cnt, fd, saved_errno; 142 char hostname[MAXHOSTNAMELEN], *stdp, tbuf[MAXLINE], fmt_cpy[MAXLINE], 143 errstr[64], tz_sign; 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 saved_errno = errno; 157 158 /* Check priority against setlogmask values. */ 159 if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) 160 return; 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 return; 172 173 /* Build the message according to RFC 5424. Tag and version. */ 174 (void)fprintf(fp, "<%d>1 ", pri); 175 /* Timestamp similar to RFC 3339. */ 176 if (gettimeofday(&now, NULL) == 0 && 177 localtime_r(&now.tv_sec, &tm) != NULL) { 178 if (tm.tm_gmtoff < 0) { 179 tz_sign = '-'; 180 tz_offset = -tm.tm_gmtoff; 181 } else { 182 tz_sign = '+'; 183 tz_offset = tm.tm_gmtoff; 184 } 185 186 (void)fprintf(fp, 187 "%04d-%02d-%02d" /* Date. */ 188 "T%02d:%02d:%02d.%06ld" /* Time. */ 189 "%c%02ld:%02ld ", /* Time zone offset. */ 190 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 191 tm.tm_hour, tm.tm_min, tm.tm_sec, now.tv_usec, 192 tz_sign, tz_offset / 3600, (tz_offset % 3600) / 60); 193 } else 194 (void)fputs(NILVALUE " ", fp); 195 /* Hostname. */ 196 (void)gethostname(hostname, sizeof(hostname)); 197 (void)fprintf(fp, "%s ", 198 hostname[0] == '\0' ? NILVALUE : hostname); 199 if (LogStat & LOG_PERROR) { 200 /* Transfer to string buffer */ 201 (void)fflush(fp); 202 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left); 203 } 204 /* Application name. */ 205 if (LogTag == NULL) 206 LogTag = _getprogname(); 207 (void)fprintf(fp, "%s ", LogTag == NULL ? NILVALUE : LogTag); 208 /* 209 * Provide the process ID regardless of whether LOG_PID has been 210 * specified, as it provides valuable information. Many 211 * applications tend not to use this, even though they should. 212 */ 213 (void)fprintf(fp, "%d ", getpid()); 214 /* Message ID. */ 215 (void)fputs(NILVALUE " ", fp); 216 /* Structured data. */ 217 (void)fputs(NILVALUE " ", fp); 218 219 /* Check to see if we can skip expanding the %m */ 220 if (strstr(fmt, "%m")) { 221 222 /* Create the second stdio hook */ 223 fmt_cookie.base = fmt_cpy; 224 fmt_cookie.left = sizeof(fmt_cpy) - 1; 225 fmt_fp = fwopen(&fmt_cookie, writehook); 226 if (fmt_fp == NULL) { 227 fclose(fp); 228 return; 229 } 230 231 /* 232 * Substitute error message for %m. Be careful not to 233 * molest an escaped percent "%%m". We want to pass it 234 * on untouched as the format is later parsed by vfprintf. 235 */ 236 for ( ; (ch = *fmt); ++fmt) { 237 if (ch == '%' && fmt[1] == 'm') { 238 ++fmt; 239 strerror_r(saved_errno, errstr, sizeof(errstr)); 240 fputs(errstr, fmt_fp); 241 } else if (ch == '%' && fmt[1] == '%') { 242 ++fmt; 243 fputc(ch, fmt_fp); 244 fputc(ch, fmt_fp); 245 } else { 246 fputc(ch, fmt_fp); 247 } 248 } 249 250 /* Null terminate if room */ 251 fputc(0, fmt_fp); 252 fclose(fmt_fp); 253 254 /* Guarantee null termination */ 255 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0'; 256 257 fmt = fmt_cpy; 258 } 259 260 /* Message. */ 261 (void)vfprintf(fp, fmt, ap); 262 (void)fclose(fp); 263 264 cnt = sizeof(tbuf) - tbuf_cookie.left; 265 266 /* Remove a trailing newline */ 267 if (tbuf[cnt - 1] == '\n') 268 cnt--; 269 270 /* Output to stderr if requested. */ 271 if (LogStat & LOG_PERROR) { 272 struct iovec iov[2]; 273 struct iovec *v = iov; 274 275 v->iov_base = stdp; 276 v->iov_len = cnt - (stdp - tbuf); 277 ++v; 278 v->iov_base = "\n"; 279 v->iov_len = 1; 280 (void)_writev(STDERR_FILENO, iov, 2); 281 } 282 283 /* Get connected, output the message to the local logger. */ 284 if (!opened) 285 openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0); 286 connectlog(); 287 288 /* 289 * If the send() failed, there are two likely scenarios: 290 * 1) syslogd was restarted. In this case make one (only) attempt 291 * to reconnect. 292 * 2) We filled our buffer due to syslogd not being able to read 293 * as fast as we write. In this case prefer to lose the current 294 * message rather than whole buffer of previously logged data. 295 */ 296 if (send(LogFile, tbuf, cnt, 0) < 0) { 297 if (errno != ENOBUFS) { 298 disconnectlog(); 299 connectlog(); 300 if (send(LogFile, tbuf, cnt, 0) >= 0) 301 return; 302 } 303 } else 304 return; 305 306 /* 307 * Output the message to the console; try not to block 308 * as a blocking console should not stop other processes. 309 * Make sure the error reported is the one from the syslogd failure. 310 */ 311 if (LogStat & LOG_CONS && 312 (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK|O_CLOEXEC, 0)) >= 313 0) { 314 struct iovec iov[2]; 315 struct iovec *v = iov; 316 317 p = strchr(tbuf, '>') + 3; 318 v->iov_base = p; 319 v->iov_len = cnt - (p - tbuf); 320 ++v; 321 v->iov_base = "\r\n"; 322 v->iov_len = 2; 323 (void)_writev(fd, iov, 2); 324 (void)_close(fd); 325 } 326 } 327 328 static void 329 syslog_cancel_cleanup(void *arg __unused) 330 { 331 332 THREAD_UNLOCK(); 333 } 334 335 void 336 vsyslog(int pri, const char *fmt, va_list ap) 337 { 338 339 THREAD_LOCK(); 340 pthread_cleanup_push(syslog_cancel_cleanup, NULL); 341 vsyslog1(pri, fmt, ap); 342 pthread_cleanup_pop(1); 343 } 344 345 /* Should be called with mutex acquired */ 346 static void 347 disconnectlog(void) 348 { 349 /* 350 * If the user closed the FD and opened another in the same slot, 351 * that's their problem. They should close it before calling on 352 * system services. 353 */ 354 if (LogFile != -1) { 355 _close(LogFile); 356 LogFile = -1; 357 } 358 connected = false; /* retry connect */ 359 } 360 361 /* Should be called with mutex acquired */ 362 static void 363 connectlog(void) 364 { 365 struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ 366 367 if (LogFile == -1) { 368 socklen_t len; 369 370 if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 371 0)) == -1) 372 return; 373 if (_getsockopt(LogFile, SOL_SOCKET, SO_SNDBUF, &len, 374 &(socklen_t){sizeof(len)}) == 0) { 375 if (len < MAXLINE) { 376 len = MAXLINE; 377 (void)_setsockopt(LogFile, SOL_SOCKET, SO_SNDBUF, 378 &len, sizeof(len)); 379 } 380 } 381 } 382 if (!connected) { 383 SyslogAddr.sun_len = sizeof(SyslogAddr); 384 SyslogAddr.sun_family = AF_UNIX; 385 386 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, 387 sizeof SyslogAddr.sun_path); 388 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 389 sizeof(SyslogAddr)) != -1) 390 connected = true; 391 else { 392 (void)_close(LogFile); 393 LogFile = -1; 394 } 395 } 396 } 397 398 static void 399 openlog_unlocked(const char *ident, int logstat, int logfac) 400 { 401 if (ident != NULL) 402 LogTag = ident; 403 LogStat = logstat; 404 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) 405 LogFacility = logfac; 406 407 if (LogStat & LOG_NDELAY) /* open immediately */ 408 connectlog(); 409 410 opened = 1; /* ident and facility has been set */ 411 } 412 413 void 414 openlog(const char *ident, int logstat, int logfac) 415 { 416 417 THREAD_LOCK(); 418 pthread_cleanup_push(syslog_cancel_cleanup, NULL); 419 openlog_unlocked(ident, logstat, logfac); 420 pthread_cleanup_pop(1); 421 } 422 423 424 void 425 closelog(void) 426 { 427 THREAD_LOCK(); 428 if (LogFile != -1) { 429 (void)_close(LogFile); 430 LogFile = -1; 431 } 432 LogTag = NULL; 433 connected = false; 434 THREAD_UNLOCK(); 435 } 436 437 /* setlogmask -- set the log mask level */ 438 int 439 setlogmask(int pmask) 440 { 441 int omask; 442 443 THREAD_LOCK(); 444 omask = LogMask; 445 if (pmask != 0) 446 LogMask = pmask; 447 THREAD_UNLOCK(); 448 return (omask); 449 } 450