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 105 int writehook(cookie, buf, len) 106 void *cookie; /* really [struct bufcookie *] */ 107 char *buf; /* characters to copy */ 108 int len; /* length to copy */ 109 { 110 struct bufcookie *h; /* private `handle' */ 111 112 h = (struct bufcookie *)cookie; 113 if (len > h->left) { 114 /* clip in case of wraparound */ 115 len = h->left; 116 } 117 if (len > 0) { 118 (void)memcpy(h->base, buf, len); /* `write' it. */ 119 h->base += len; 120 h->left -= len; 121 } 122 return 0; 123 } 124 125 /* 126 * syslog, vsyslog -- 127 * print message on log file; output is intended for syslogd(8). 128 */ 129 void 130 syslog(int pri, const char *fmt, ...) 131 { 132 va_list ap; 133 134 va_start(ap, fmt); 135 vsyslog(pri, fmt, ap); 136 va_end(ap); 137 } 138 139 void 140 vsyslog(pri, fmt, ap) 141 int pri; 142 const char *fmt; 143 va_list ap; 144 { 145 int cnt; 146 char ch, *p; 147 time_t now; 148 int fd, saved_errno; 149 char *stdp, tbuf[2048], fmt_cpy[1024], timbuf[26], errstr[64]; 150 FILE *fp, *fmt_fp; 151 struct bufcookie tbuf_cookie; 152 struct bufcookie fmt_cookie; 153 154 #define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID 155 /* Check for invalid bits. */ 156 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) { 157 syslog(INTERNALLOG, 158 "syslog: unknown facility/priority: %x", pri); 159 pri &= LOG_PRIMASK|LOG_FACMASK; 160 } 161 162 THREAD_LOCK(); 163 164 /* Check priority against setlogmask values. */ 165 if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) { 166 THREAD_UNLOCK(); 167 return; 168 } 169 170 saved_errno = errno; 171 172 /* Set default facility if none specified. */ 173 if ((pri & LOG_FACMASK) == 0) 174 pri |= LogFacility; 175 176 /* Create the primary stdio hook */ 177 tbuf_cookie.base = tbuf; 178 tbuf_cookie.left = sizeof(tbuf); 179 fp = fwopen(&tbuf_cookie, writehook); 180 if (fp == NULL) { 181 THREAD_UNLOCK(); 182 return; 183 } 184 185 /* Build the message. */ 186 (void)time(&now); 187 (void)fprintf(fp, "<%d>", pri); 188 (void)fprintf(fp, "%.15s ", ctime_r(&now, timbuf) + 4); 189 if (LogStat & LOG_PERROR) { 190 /* Transfer to string buffer */ 191 (void)fflush(fp); 192 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left); 193 } 194 if (LogTag == NULL) 195 LogTag = _getprogname(); 196 if (LogTag != NULL) 197 (void)fprintf(fp, "%s", LogTag); 198 if (LogStat & LOG_PID) 199 (void)fprintf(fp, "[%d]", getpid()); 200 if (LogTag != NULL) { 201 (void)fprintf(fp, ": "); 202 } 203 204 /* Check to see if we can skip expanding the %m */ 205 if (strstr(fmt, "%m")) { 206 207 /* Create the second stdio hook */ 208 fmt_cookie.base = fmt_cpy; 209 fmt_cookie.left = sizeof(fmt_cpy) - 1; 210 fmt_fp = fwopen(&fmt_cookie, writehook); 211 if (fmt_fp == NULL) { 212 fclose(fp); 213 THREAD_UNLOCK(); 214 return; 215 } 216 217 /* 218 * Substitute error message for %m. Be careful not to 219 * molest an escaped percent "%%m". We want to pass it 220 * on untouched as the format is later parsed by vfprintf. 221 */ 222 for ( ; (ch = *fmt); ++fmt) { 223 if (ch == '%' && fmt[1] == 'm') { 224 ++fmt; 225 strerror_r(saved_errno, errstr, sizeof(errstr)); 226 fputs(errstr, fmt_fp); 227 } else if (ch == '%' && fmt[1] == '%') { 228 ++fmt; 229 fputc(ch, fmt_fp); 230 fputc(ch, fmt_fp); 231 } else { 232 fputc(ch, fmt_fp); 233 } 234 } 235 236 /* Null terminate if room */ 237 fputc(0, fmt_fp); 238 fclose(fmt_fp); 239 240 /* Guarantee null termination */ 241 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0'; 242 243 fmt = fmt_cpy; 244 } 245 246 (void)vfprintf(fp, fmt, ap); 247 (void)fclose(fp); 248 249 cnt = sizeof(tbuf) - tbuf_cookie.left; 250 251 /* Remove a trailing newline */ 252 if (tbuf[cnt - 1] == '\n') 253 cnt--; 254 255 /* Output to stderr if requested. */ 256 if (LogStat & LOG_PERROR) { 257 struct iovec iov[2]; 258 struct iovec *v = iov; 259 260 v->iov_base = stdp; 261 v->iov_len = cnt - (stdp - tbuf); 262 ++v; 263 v->iov_base = "\n"; 264 v->iov_len = 1; 265 (void)_writev(STDERR_FILENO, iov, 2); 266 } 267 268 /* Get connected, output the message to the local logger. */ 269 if (!opened) 270 openlog_unlocked(LogTag, LogStat | LOG_NDELAY, 0); 271 connectlog(); 272 273 /* 274 * If the send() failed, there are two likely scenarios: 275 * 1) syslogd was restarted 276 * 2) /var/run/log is out of socket buffer space, which 277 * in most cases means local DoS. 278 * We attempt to reconnect to /var/run/log to take care of 279 * case #1 and keep send()ing data to cover case #2 280 * to give syslogd a chance to empty its socket buffer. 281 * 282 * If we are working with a priveleged socket, then take 283 * only one attempt, because we don't want to freeze a 284 * critical application like su(1) or sshd(8). 285 * 286 */ 287 288 if (send(LogFile, tbuf, cnt, 0) < 0) { 289 if (errno != ENOBUFS) { 290 disconnectlog(); 291 connectlog(); 292 } 293 do { 294 usleep(1); 295 if (send(LogFile, tbuf, cnt, 0) >= 0) { 296 THREAD_UNLOCK(); 297 return; 298 } 299 if (status == CONNPRIV) 300 break; 301 } while (errno == ENOBUFS); 302 } else { 303 THREAD_UNLOCK(); 304 return; 305 } 306 307 /* 308 * Output the message to the console; try not to block 309 * as a blocking console should not stop other processes. 310 * Make sure the error reported is the one from the syslogd failure. 311 */ 312 if (LogStat & LOG_CONS && 313 (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK, 0)) >= 0) { 314 struct iovec iov[2]; 315 struct iovec *v = iov; 316 317 p = strchr(tbuf, '>') + 1; 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 THREAD_UNLOCK(); 328 } 329 330 /* Should be called with mutex acquired */ 331 static void 332 disconnectlog() 333 { 334 /* 335 * If the user closed the FD and opened another in the same slot, 336 * that's their problem. They should close it before calling on 337 * system services. 338 */ 339 if (LogFile != -1) { 340 _close(LogFile); 341 LogFile = -1; 342 } 343 status = NOCONN; /* retry connect */ 344 } 345 346 /* Should be called with mutex acquired */ 347 static void 348 connectlog() 349 { 350 struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ 351 352 if (LogFile == -1) { 353 if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) 354 return; 355 (void)_fcntl(LogFile, F_SETFD, 1); 356 } 357 if (LogFile != -1 && status == NOCONN) { 358 SyslogAddr.sun_len = sizeof(SyslogAddr); 359 SyslogAddr.sun_family = AF_UNIX; 360 361 /* 362 * First try priveleged socket. If no success, 363 * then try default socket. 364 */ 365 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG_PRIV, 366 sizeof SyslogAddr.sun_path); 367 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 368 sizeof(SyslogAddr)) != -1) 369 status = CONNPRIV; 370 371 if (status == NOCONN) { 372 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, 373 sizeof SyslogAddr.sun_path); 374 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 375 sizeof(SyslogAddr)) != -1) 376 status = CONNDEF; 377 } 378 379 if (status == NOCONN) { 380 /* 381 * Try the old "/dev/log" path, for backward 382 * compatibility. 383 */ 384 (void)strncpy(SyslogAddr.sun_path, _PATH_OLDLOG, 385 sizeof SyslogAddr.sun_path); 386 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 387 sizeof(SyslogAddr)) != -1) 388 status = CONNDEF; 389 } 390 391 if (status == NOCONN) { 392 (void)_close(LogFile); 393 LogFile = -1; 394 } 395 } 396 } 397 398 static void 399 openlog_unlocked(ident, logstat, logfac) 400 const char *ident; 401 int logstat, logfac; 402 { 403 if (ident != NULL) 404 LogTag = ident; 405 LogStat = logstat; 406 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) 407 LogFacility = logfac; 408 409 if (LogStat & LOG_NDELAY) /* open immediately */ 410 connectlog(); 411 412 opened = 1; /* ident and facility has been set */ 413 } 414 415 void 416 openlog(ident, logstat, logfac) 417 const char *ident; 418 int logstat, logfac; 419 { 420 THREAD_LOCK(); 421 openlog_unlocked(ident, logstat, logfac); 422 THREAD_UNLOCK(); 423 } 424 425 426 void 427 closelog() 428 { 429 THREAD_LOCK(); 430 (void)_close(LogFile); 431 LogFile = -1; 432 LogTag = NULL; 433 status = NOCONN; 434 THREAD_UNLOCK(); 435 } 436 437 /* setlogmask -- set the log mask level */ 438 int 439 setlogmask(pmask) 440 int pmask; 441 { 442 int omask; 443 444 THREAD_LOCK(); 445 omask = LogMask; 446 if (pmask != 0) 447 LogMask = pmask; 448 THREAD_UNLOCK(); 449 return (omask); 450 } 451