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 <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <time.h> 55 #include <unistd.h> 56 57 #include <stdarg.h> 58 #include "un-namespace.h" 59 60 #include "libc_private.h" 61 62 static int LogFile = -1; /* fd for log */ 63 static int status; /* connection status */ 64 static int opened; /* have done openlog() */ 65 static int LogStat = 0; /* status bits, set by openlog() */ 66 static const char *LogTag = NULL; /* string to tag the entry with */ 67 static int LogFacility = LOG_USER; /* default facility code */ 68 static int LogMask = 0xff; /* mask of priorities to be logged */ 69 70 static void disconnectlog(void); /* disconnect from syslogd */ 71 static void connectlog(void); /* (re)connect to syslogd */ 72 73 enum { 74 NOCONN = 0, 75 CONNDEF, 76 CONNPRIV, 77 }; 78 79 /* 80 * Format of the magic cookie passed through the stdio hook 81 */ 82 struct bufcookie { 83 char *base; /* start of buffer */ 84 int left; 85 }; 86 87 /* 88 * stdio write hook for writing to a static string buffer 89 * XXX: Maybe one day, dynamically allocate it so that the line length 90 * is `unlimited'. 91 */ 92 static 93 int writehook(cookie, buf, len) 94 void *cookie; /* really [struct bufcookie *] */ 95 char *buf; /* characters to copy */ 96 int len; /* length to copy */ 97 { 98 struct bufcookie *h; /* private `handle' */ 99 100 h = (struct bufcookie *)cookie; 101 if (len > h->left) { 102 /* clip in case of wraparound */ 103 len = h->left; 104 } 105 if (len > 0) { 106 (void)memcpy(h->base, buf, len); /* `write' it. */ 107 h->base += len; 108 h->left -= len; 109 } 110 return 0; 111 } 112 113 /* 114 * syslog, vsyslog -- 115 * print message on log file; output is intended for syslogd(8). 116 */ 117 void 118 syslog(int pri, const char *fmt, ...) 119 { 120 va_list ap; 121 122 va_start(ap, fmt); 123 vsyslog(pri, fmt, ap); 124 va_end(ap); 125 } 126 127 void 128 vsyslog(pri, fmt, ap) 129 int pri; 130 const char *fmt; 131 va_list ap; 132 { 133 int cnt; 134 char ch, *p; 135 time_t now; 136 int fd, saved_errno; 137 char *stdp, tbuf[2048], fmt_cpy[1024], timbuf[26]; 138 FILE *fp, *fmt_fp; 139 struct bufcookie tbuf_cookie; 140 struct bufcookie fmt_cookie; 141 142 #define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID 143 /* Check for invalid bits. */ 144 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) { 145 syslog(INTERNALLOG, 146 "syslog: unknown facility/priority: %x", pri); 147 pri &= LOG_PRIMASK|LOG_FACMASK; 148 } 149 150 /* Check priority against setlogmask values. */ 151 if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) 152 return; 153 154 saved_errno = errno; 155 156 /* Set default facility if none specified. */ 157 if ((pri & LOG_FACMASK) == 0) 158 pri |= LogFacility; 159 160 /* Create the primary stdio hook */ 161 tbuf_cookie.base = tbuf; 162 tbuf_cookie.left = sizeof(tbuf); 163 fp = fwopen(&tbuf_cookie, writehook); 164 if (fp == NULL) 165 return; 166 167 /* Build the message. */ 168 (void)time(&now); 169 (void)fprintf(fp, "<%d>", pri); 170 (void)fprintf(fp, "%.15s ", ctime_r(&now, timbuf) + 4); 171 if (LogStat & LOG_PERROR) { 172 /* Transfer to string buffer */ 173 (void)fflush(fp); 174 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left); 175 } 176 if (LogTag == NULL) 177 LogTag = _getprogname(); 178 if (LogTag != NULL) 179 (void)fprintf(fp, "%s", LogTag); 180 if (LogStat & LOG_PID) 181 (void)fprintf(fp, "[%d]", getpid()); 182 if (LogTag != NULL) { 183 (void)fprintf(fp, ": "); 184 } 185 186 /* Check to see if we can skip expanding the %m */ 187 if (strstr(fmt, "%m")) { 188 189 /* Create the second stdio hook */ 190 fmt_cookie.base = fmt_cpy; 191 fmt_cookie.left = sizeof(fmt_cpy) - 1; 192 fmt_fp = fwopen(&fmt_cookie, writehook); 193 if (fmt_fp == NULL) { 194 fclose(fp); 195 return; 196 } 197 198 /* 199 * Substitute error message for %m. Be careful not to 200 * molest an escaped percent "%%m". We want to pass it 201 * on untouched as the format is later parsed by vfprintf. 202 */ 203 for ( ; (ch = *fmt); ++fmt) { 204 if (ch == '%' && fmt[1] == 'm') { 205 ++fmt; 206 fputs(strerror(saved_errno), fmt_fp); 207 } else if (ch == '%' && fmt[1] == '%') { 208 ++fmt; 209 fputc(ch, fmt_fp); 210 fputc(ch, fmt_fp); 211 } else { 212 fputc(ch, fmt_fp); 213 } 214 } 215 216 /* Null terminate if room */ 217 fputc(0, fmt_fp); 218 fclose(fmt_fp); 219 220 /* Guarantee null termination */ 221 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0'; 222 223 fmt = fmt_cpy; 224 } 225 226 (void)vfprintf(fp, fmt, ap); 227 (void)fclose(fp); 228 229 cnt = sizeof(tbuf) - tbuf_cookie.left; 230 231 /* Remove a trailing newline */ 232 if (tbuf[cnt - 1] == '\n') 233 cnt--; 234 235 /* Output to stderr if requested. */ 236 if (LogStat & LOG_PERROR) { 237 struct iovec iov[2]; 238 struct iovec *v = iov; 239 240 v->iov_base = stdp; 241 v->iov_len = cnt - (stdp - tbuf); 242 ++v; 243 v->iov_base = "\n"; 244 v->iov_len = 1; 245 (void)_writev(STDERR_FILENO, iov, 2); 246 } 247 248 /* Get connected, output the message to the local logger. */ 249 if (!opened) 250 openlog(LogTag, LogStat | LOG_NDELAY, 0); 251 connectlog(); 252 253 /* 254 * If the send() failed, there are two likely scenarios: 255 * 1) syslogd was restarted 256 * 2) /var/run/log is out of socket buffer space, which 257 * in most cases means local DoS. 258 * We attempt to reconnect to /var/run/log to take care of 259 * case #1 and keep send()ing data to cover case #2 260 * to give syslogd a chance to empty its socket buffer. 261 * 262 * If we are working with a priveleged socket, then take 263 * only one attempt, because we don't want to freeze a 264 * critical application like su(1) or sshd(8). 265 * 266 */ 267 268 if (send(LogFile, tbuf, cnt, 0) < 0) { 269 if (errno != ENOBUFS) { 270 disconnectlog(); 271 connectlog(); 272 } 273 do { 274 usleep(1); 275 if (send(LogFile, tbuf, cnt, 0) >= 0) 276 break; 277 if (status == CONNPRIV) 278 break; 279 } while (errno == ENOBUFS); 280 } 281 282 /* 283 * Output the message to the console; try not to block 284 * as a blocking console should not stop other processes. 285 * Make sure the error reported is the one from the syslogd failure. 286 */ 287 if (LogStat & LOG_CONS && 288 (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK, 0)) >= 0) { 289 struct iovec iov[2]; 290 struct iovec *v = iov; 291 292 p = strchr(tbuf, '>') + 1; 293 v->iov_base = p; 294 v->iov_len = cnt - (p - tbuf); 295 ++v; 296 v->iov_base = "\r\n"; 297 v->iov_len = 2; 298 (void)_writev(fd, iov, 2); 299 (void)_close(fd); 300 } 301 } 302 static void 303 disconnectlog() 304 { 305 /* 306 * If the user closed the FD and opened another in the same slot, 307 * that's their problem. They should close it before calling on 308 * system services. 309 */ 310 if (LogFile != -1) { 311 _close(LogFile); 312 LogFile = -1; 313 } 314 status = NOCONN; /* retry connect */ 315 } 316 317 static void 318 connectlog() 319 { 320 struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ 321 322 if (LogFile == -1) { 323 if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) 324 return; 325 (void)_fcntl(LogFile, F_SETFD, 1); 326 } 327 if (LogFile != -1 && status == NOCONN) { 328 SyslogAddr.sun_len = sizeof(SyslogAddr); 329 SyslogAddr.sun_family = AF_UNIX; 330 331 /* 332 * First try priveleged socket. If no success, 333 * then try default socket. 334 */ 335 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG_PRIV, 336 sizeof SyslogAddr.sun_path); 337 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 338 sizeof(SyslogAddr)) != -1) 339 status = CONNPRIV; 340 341 if (status == NOCONN) { 342 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, 343 sizeof SyslogAddr.sun_path); 344 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 345 sizeof(SyslogAddr)) != -1) 346 status = CONNDEF; 347 } 348 349 if (status == NOCONN) { 350 /* 351 * Try the old "/dev/log" path, for backward 352 * compatibility. 353 */ 354 (void)strncpy(SyslogAddr.sun_path, _PATH_OLDLOG, 355 sizeof SyslogAddr.sun_path); 356 if (_connect(LogFile, (struct sockaddr *)&SyslogAddr, 357 sizeof(SyslogAddr)) != -1) 358 status = CONNDEF; 359 } 360 361 if (status == NOCONN) { 362 (void)_close(LogFile); 363 LogFile = -1; 364 } 365 } 366 } 367 368 void 369 openlog(ident, logstat, logfac) 370 const char *ident; 371 int logstat, logfac; 372 { 373 if (ident != NULL) 374 LogTag = ident; 375 LogStat = logstat; 376 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) 377 LogFacility = logfac; 378 379 if (LogStat & LOG_NDELAY) /* open immediately */ 380 connectlog(); 381 382 opened = 1; /* ident and facility has been set */ 383 } 384 385 void 386 closelog() 387 { 388 (void)_close(LogFile); 389 LogFile = -1; 390 LogTag = NULL; 391 status = NOCONN; 392 } 393 394 /* setlogmask -- set the log mask level */ 395 int 396 setlogmask(pmask) 397 int pmask; 398 { 399 int omask; 400 401 omask = LogMask; 402 if (pmask != 0) 403 LogMask = pmask; 404 return (omask); 405 } 406