1 /* $NetBSD: syslog.c,v 1.54 2014/09/18 13:58:20 christos Exp $ */ 2 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 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)syslog.c 8.5 (Berkeley) 4/29/95"; 36 #else 37 __RCSID("$NetBSD: syslog.c,v 1.54 2014/09/18 13:58:20 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <sys/types.h> 43 #include <sys/param.h> 44 #include <sys/socket.h> 45 #include <sys/syslog.h> 46 #include <sys/uio.h> 47 #include <sys/un.h> 48 #include <netdb.h> 49 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <paths.h> 53 #include <stdarg.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <time.h> 58 #include <unistd.h> 59 #include "reentrant.h" 60 #include "extern.h" 61 62 #ifdef __weak_alias 63 __weak_alias(closelog,_closelog) 64 __weak_alias(openlog,_openlog) 65 __weak_alias(setlogmask,_setlogmask) 66 __weak_alias(syslog,_syslog) 67 __weak_alias(vsyslog,_vsyslog) 68 __weak_alias(syslogp,_syslogp) 69 __weak_alias(vsyslogp,_vsyslogp) 70 #endif 71 72 static struct syslog_data sdata = SYSLOG_DATA_INIT; 73 74 static void openlog_unlocked_r(const char *, int, int, 75 struct syslog_data *); 76 static void disconnectlog_r(struct syslog_data *); 77 static void connectlog_r(struct syslog_data *); 78 79 #define LOG_SIGNAL_SAFE (int)0x80000000 80 81 82 #ifdef _REENTRANT 83 static mutex_t syslog_mutex = MUTEX_INITIALIZER; 84 #endif 85 86 /* 87 * syslog, vsyslog -- 88 * print message on log file; output is intended for syslogd(8). 89 */ 90 void 91 syslog(int pri, const char *fmt, ...) 92 { 93 va_list ap; 94 95 va_start(ap, fmt); 96 vsyslog(pri, fmt, ap); 97 va_end(ap); 98 } 99 100 void 101 vsyslog(int pri, const char *fmt, va_list ap) 102 { 103 vsyslog_r(pri, &sdata, fmt, ap); 104 } 105 106 /* 107 * syslogp, vsyslogp -- 108 * like syslog but take additional arguments for MSGID and SD 109 */ 110 void 111 syslogp(int pri, const char *msgid, const char *sdfmt, const char *msgfmt, ...) 112 { 113 va_list ap; 114 115 va_start(ap, msgfmt); 116 vsyslogp(pri, msgid, sdfmt, msgfmt, ap); 117 va_end(ap); 118 } 119 120 void 121 vsyslogp(int pri, const char *msgid, const char *sdfmt, const char *msgfmt, va_list ap) 122 { 123 vsyslogp_r(pri, &sdata, msgid, sdfmt, msgfmt, ap); 124 } 125 126 void 127 openlog(const char *ident, int logstat, int logfac) 128 { 129 openlog_r(ident, logstat, logfac, &sdata); 130 } 131 132 void 133 closelog(void) 134 { 135 closelog_r(&sdata); 136 } 137 138 /* setlogmask -- set the log mask level */ 139 int 140 setlogmask(int pmask) 141 { 142 return setlogmask_r(pmask, &sdata); 143 } 144 145 /* Reentrant version of syslog, i.e. syslog_r() */ 146 147 void 148 syslog_r(int pri, struct syslog_data *data, const char *fmt, ...) 149 { 150 va_list ap; 151 152 va_start(ap, fmt); 153 vsyslog_r(pri, data, fmt, ap); 154 va_end(ap); 155 } 156 157 void 158 syslogp_r(int pri, struct syslog_data *data, const char *msgid, 159 const char *sdfmt, const char *msgfmt, ...) 160 { 161 va_list ap; 162 163 va_start(ap, msgfmt); 164 vsyslogp_r(pri, data, msgid, sdfmt, msgfmt, ap); 165 va_end(ap); 166 } 167 168 void 169 syslog_ss(int pri, struct syslog_data *data, const char *fmt, ...) 170 { 171 va_list ap; 172 173 va_start(ap, fmt); 174 vsyslog_r(pri | LOG_SIGNAL_SAFE, data, fmt, ap); 175 va_end(ap); 176 } 177 178 void 179 syslogp_ss(int pri, struct syslog_data *data, const char *msgid, 180 const char *sdfmt, const char *msgfmt, ...) 181 { 182 va_list ap; 183 184 va_start(ap, msgfmt); 185 vsyslogp_r(pri | LOG_SIGNAL_SAFE, data, msgid, sdfmt, msgfmt, ap); 186 va_end(ap); 187 } 188 189 void 190 vsyslog_ss(int pri, struct syslog_data *data, const char *fmt, va_list ap) 191 { 192 vsyslog_r(pri | LOG_SIGNAL_SAFE, data, fmt, ap); 193 } 194 195 void 196 vsyslogp_ss(int pri, struct syslog_data *data, const char *msgid, 197 const char *sdfmt, const char *msgfmt, va_list ap) 198 { 199 vsyslogp_r(pri | LOG_SIGNAL_SAFE, data, msgid, sdfmt, msgfmt, ap); 200 } 201 202 203 void 204 vsyslog_r(int pri, struct syslog_data *data, const char *fmt, va_list ap) 205 { 206 vsyslogp_r(pri, data, NULL, NULL, fmt, ap); 207 } 208 209 void 210 vsyslogp_r(int pri, struct syslog_data *data, const char *msgid, 211 const char *sdfmt, const char *msgfmt, va_list ap) 212 { 213 static const char BRCOSP[] = "]: "; 214 static const char CRLF[] = "\r\n"; 215 size_t cnt, prlen, tries; 216 char ch, *p, *t; 217 struct timeval tv; 218 struct tm tmnow; 219 time_t now; 220 int fd, saved_errno; 221 #define TBUF_LEN 2048 222 #define FMT_LEN 1024 223 #define MAXTRIES 10 224 char tbuf[TBUF_LEN], fmt_cpy[FMT_LEN], fmt_cat[FMT_LEN] = ""; 225 size_t tbuf_left, fmt_left, msgsdlen; 226 char *fmt = fmt_cat; 227 int signal_safe = pri & LOG_SIGNAL_SAFE; 228 struct iovec iov[7]; /* prog + [ + pid + ]: + fmt + crlf */ 229 int opened, iovcnt; 230 231 pri &= ~LOG_SIGNAL_SAFE; 232 233 #define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID 234 /* Check for invalid bits. */ 235 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) { 236 syslog_r(INTERNALLOG | signal_safe, data, 237 "syslog_r: unknown facility/priority: %x", pri); 238 pri &= LOG_PRIMASK|LOG_FACMASK; 239 } 240 241 /* Check priority against setlogmask values. */ 242 if (!(LOG_MASK(LOG_PRI(pri)) & data->log_mask)) 243 return; 244 245 saved_errno = errno; 246 247 /* Set default facility if none specified. */ 248 if ((pri & LOG_FACMASK) == 0) 249 pri |= data->log_fac; 250 251 /* Build the message. */ 252 p = tbuf; 253 tbuf_left = TBUF_LEN; 254 255 #define DEC() \ 256 do { \ 257 if (prlen >= tbuf_left) \ 258 prlen = tbuf_left - 1; \ 259 p += prlen; \ 260 tbuf_left -= prlen; \ 261 } while (/*CONSTCOND*/0) 262 263 prlen = snprintf_ss(p, tbuf_left, "<%d>1 ", pri); 264 DEC(); 265 266 if (!signal_safe && (gettimeofday(&tv, NULL) != -1)) { 267 /* strftime() implies tzset(), localtime_r() doesn't. */ 268 tzset(); 269 now = (time_t) tv.tv_sec; 270 localtime_r(&now, &tmnow); 271 272 prlen = strftime(p, tbuf_left, "%FT%T", &tmnow); 273 DEC(); 274 prlen = snprintf(p, tbuf_left, ".%06ld", (long)tv.tv_usec); 275 DEC(); 276 prlen = strftime(p, tbuf_left-1, "%z", &tmnow); 277 /* strftime gives eg. "+0200", but we need "+02:00" */ 278 if (prlen == 5) { 279 p[prlen+1] = p[prlen]; 280 p[prlen] = p[prlen-1]; 281 p[prlen-1] = p[prlen-2]; 282 p[prlen-2] = ':'; 283 prlen += 1; 284 } 285 } else { 286 prlen = snprintf_ss(p, tbuf_left, "-"); 287 #if 0 288 /* 289 * if gmtime_r() was signal-safe we could output 290 * the UTC-time: 291 */ 292 gmtime_r(&now, &tmnow); 293 prlen = strftime(p, tbuf_left, "%FT%TZ", &tmnow); 294 #endif 295 } 296 297 #if !defined(__minix) 298 if (data == &sdata) 299 mutex_lock(&syslog_mutex); 300 #endif /* !defined(__minix) */ 301 302 if (data->log_hostname[0] == '\0' && gethostname(data->log_hostname, 303 sizeof(data->log_hostname)) == -1) { 304 /* can this really happen? */ 305 data->log_hostname[0] = '-'; 306 data->log_hostname[1] = '\0'; 307 } 308 309 DEC(); 310 prlen = snprintf_ss(p, tbuf_left, " %s ", data->log_hostname); 311 312 if (data->log_tag == NULL) 313 data->log_tag = getprogname(); 314 315 DEC(); 316 prlen = snprintf_ss(p, tbuf_left, "%s ", 317 data->log_tag ? data->log_tag : "-"); 318 319 #if !defined(__minix) 320 if (data == &sdata) 321 mutex_unlock(&syslog_mutex); 322 #endif /* !defined(__minix) */ 323 324 if (data->log_stat & (LOG_PERROR|LOG_CONS)) { 325 iovcnt = 0; 326 iov[iovcnt].iov_base = p; 327 iov[iovcnt].iov_len = prlen - 1; 328 iovcnt++; 329 } 330 DEC(); 331 332 if (data->log_stat & LOG_PID) { 333 prlen = snprintf_ss(p, tbuf_left, "%d ", getpid()); 334 if (data->log_stat & (LOG_PERROR|LOG_CONS)) { 335 iov[iovcnt].iov_base = __UNCONST("["); 336 iov[iovcnt].iov_len = 1; 337 iovcnt++; 338 iov[iovcnt].iov_base = p; 339 iov[iovcnt].iov_len = prlen - 1; 340 iovcnt++; 341 iov[iovcnt].iov_base = __UNCONST(BRCOSP); 342 iov[iovcnt].iov_len = 3; 343 iovcnt++; 344 } 345 } else { 346 prlen = snprintf_ss(p, tbuf_left, "- "); 347 if (data->log_stat & (LOG_PERROR|LOG_CONS)) { 348 iov[iovcnt].iov_base = __UNCONST(BRCOSP + 1); 349 iov[iovcnt].iov_len = 2; 350 iovcnt++; 351 } 352 } 353 DEC(); 354 355 /* 356 * concat the format strings, then use one vsnprintf() 357 */ 358 if (msgid != NULL && *msgid != '\0') { 359 strlcat(fmt_cat, msgid, FMT_LEN); 360 strlcat(fmt_cat, " ", FMT_LEN); 361 } else 362 strlcat(fmt_cat, "- ", FMT_LEN); 363 364 if (sdfmt != NULL && *sdfmt != '\0') { 365 strlcat(fmt_cat, sdfmt, FMT_LEN); 366 } else 367 strlcat(fmt_cat, "-", FMT_LEN); 368 369 if (data->log_stat & (LOG_PERROR|LOG_CONS)) 370 msgsdlen = strlen(fmt_cat) + 1; 371 else 372 msgsdlen = 0; /* XXX: GCC */ 373 374 if (msgfmt != NULL && *msgfmt != '\0') { 375 strlcat(fmt_cat, " ", FMT_LEN); 376 strlcat(fmt_cat, msgfmt, FMT_LEN); 377 } 378 379 /* 380 * We wouldn't need this mess if printf handled %m, or if 381 * strerror() had been invented before syslog(). 382 */ 383 for (t = fmt_cpy, fmt_left = FMT_LEN; (ch = *fmt) != '\0'; ++fmt) { 384 if (ch == '%' && fmt[1] == 'm') { 385 char ebuf[128]; 386 ++fmt; 387 if (signal_safe || 388 strerror_r(saved_errno, ebuf, sizeof(ebuf))) 389 prlen = snprintf_ss(t, fmt_left, "Error %d", 390 saved_errno); 391 else 392 prlen = snprintf_ss(t, fmt_left, "%s", ebuf); 393 if (prlen >= fmt_left) 394 prlen = fmt_left - 1; 395 t += prlen; 396 fmt_left -= prlen; 397 } else if (ch == '%' && fmt[1] == '%' && fmt_left > 2) { 398 *t++ = '%'; 399 *t++ = '%'; 400 fmt++; 401 fmt_left -= 2; 402 } else { 403 if (fmt_left > 1) { 404 *t++ = ch; 405 fmt_left--; 406 } 407 } 408 } 409 *t = '\0'; 410 411 if (signal_safe) 412 prlen = vsnprintf_ss(p, tbuf_left, fmt_cpy, ap); 413 else 414 prlen = vsnprintf(p, tbuf_left, fmt_cpy, ap); 415 416 if (data->log_stat & (LOG_PERROR|LOG_CONS)) { 417 iov[iovcnt].iov_base = p + msgsdlen; 418 iov[iovcnt].iov_len = prlen - msgsdlen; 419 iovcnt++; 420 } 421 422 DEC(); 423 cnt = p - tbuf; 424 425 /* Output to stderr if requested. */ 426 if (data->log_stat & LOG_PERROR) { 427 iov[iovcnt].iov_base = __UNCONST(CRLF + 1); 428 iov[iovcnt].iov_len = 1; 429 (void)writev(STDERR_FILENO, iov, iovcnt + 1); 430 } 431 432 /* Get connected, output the message to the local logger. */ 433 #if !defined(__minix) 434 if (data == &sdata) 435 mutex_lock(&syslog_mutex); 436 #endif /* !defined(__minix) */ 437 opened = !data->log_opened; 438 if (opened) 439 openlog_unlocked_r(data->log_tag, data->log_stat, 0, data); 440 connectlog_r(data); 441 442 /* 443 * If the send() failed, there are two likely scenarios: 444 * 1) syslogd was restarted 445 * 2) /dev/log is out of socket buffer space 446 * We attempt to reconnect to /dev/log to take care of 447 * case #1 and keep send()ing data to cover case #2 448 * to give syslogd a chance to empty its socket buffer. 449 */ 450 for (tries = 0; tries < MAXTRIES; tries++) { 451 if (send(data->log_file, tbuf, cnt, 0) != -1) 452 break; 453 if (errno != ENOBUFS) { 454 disconnectlog_r(data); 455 connectlog_r(data); 456 } else 457 (void)usleep(1); 458 } 459 460 /* 461 * Output the message to the console; try not to block 462 * as a blocking console should not stop other processes. 463 * Make sure the error reported is the one from the syslogd failure. 464 */ 465 if (tries == MAXTRIES && (data->log_stat & LOG_CONS) && 466 (fd = open(_PATH_CONSOLE, 467 O_WRONLY | O_NONBLOCK | O_CLOEXEC, 0)) >= 0) { 468 iov[iovcnt].iov_base = __UNCONST(CRLF); 469 iov[iovcnt].iov_len = 2; 470 (void)writev(fd, iov, iovcnt + 1); 471 (void)close(fd); 472 } 473 474 #if !defined(__minix) 475 if (data == &sdata) 476 mutex_unlock(&syslog_mutex); 477 #endif /* !defined(__minix) */ 478 479 if (data != &sdata && opened) { 480 /* preserve log tag */ 481 const char *ident = data->log_tag; 482 closelog_r(data); 483 data->log_tag = ident; 484 } 485 } 486 487 static void 488 disconnectlog_r(struct syslog_data *data) 489 { 490 /* 491 * If the user closed the FD and opened another in the same slot, 492 * that's their problem. They should close it before calling on 493 * system services. 494 */ 495 if (data->log_file != -1) { 496 (void)close(data->log_file); 497 data->log_file = -1; 498 } 499 data->log_connected = 0; /* retry connect */ 500 } 501 502 static void 503 connectlog_r(struct syslog_data *data) 504 { 505 /* AF_UNIX address of local logger */ 506 static const struct sockaddr_un sun = { 507 .sun_family = AF_LOCAL, 508 .sun_len = sizeof(sun), 509 .sun_path = _PATH_LOG, 510 }; 511 512 if (data->log_file == -1 || fcntl(data->log_file, F_GETFL, 0) == -1) { 513 if ((data->log_file = socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 514 0)) == -1) 515 return; 516 data->log_connected = 0; 517 } 518 if (!data->log_connected) { 519 if (connect(data->log_file, 520 (const struct sockaddr *)(const void *)&sun, 521 (socklen_t)sizeof(sun)) == -1) 522 { 523 (void)close(data->log_file); 524 data->log_file = -1; 525 } else 526 data->log_connected = 1; 527 } 528 } 529 530 static void 531 openlog_unlocked_r(const char *ident, int logstat, int logfac, 532 struct syslog_data *data) 533 { 534 if (ident != NULL) 535 data->log_tag = ident; 536 data->log_stat = logstat; 537 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) 538 data->log_fac = logfac; 539 540 if (data->log_stat & LOG_NDELAY) /* open immediately */ 541 connectlog_r(data); 542 543 data->log_opened = 1; 544 } 545 546 void 547 openlog_r(const char *ident, int logstat, int logfac, struct syslog_data *data) 548 { 549 #if !defined(__minix) 550 if (data == &sdata) 551 mutex_lock(&syslog_mutex); 552 #endif /* !defined(__minix) */ 553 openlog_unlocked_r(ident, logstat, logfac, data); 554 #if !defined(__minix) 555 if (data == &sdata) 556 mutex_unlock(&syslog_mutex); 557 #endif /* !defined(__minix) */ 558 } 559 560 void 561 closelog_r(struct syslog_data *data) 562 { 563 #if !defined(__minix) 564 if (data == &sdata) 565 mutex_lock(&syslog_mutex); 566 #endif /* !defined(__minix) */ 567 (void)close(data->log_file); 568 data->log_file = -1; 569 data->log_connected = 0; 570 data->log_tag = NULL; 571 #if !defined(__minix) 572 if (data == &sdata) 573 mutex_unlock(&syslog_mutex); 574 #endif /* !defined(__minix) */ 575 } 576 577 int 578 setlogmask_r(int pmask, struct syslog_data *data) 579 { 580 int omask; 581 582 omask = data->log_mask; 583 if (pmask != 0) 584 data->log_mask = pmask; 585 return omask; 586 } 587