syslog.c revision 34072
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/* 36static char sccsid[] = "@(#)syslog.c 8.5 (Berkeley) 4/29/95"; 37*/ 38static const char rcsid[] = 39 "$Id: syslog.c,v 1.14 1998/03/05 22:17:59 brian Exp $"; 40#endif /* LIBC_SCCS and not lint */ 41 42#include <sys/types.h> 43#include <sys/socket.h> 44#include <sys/syslog.h> 45#include <sys/uio.h> 46#include <sys/un.h> 47#include <netdb.h> 48 49#include <errno.h> 50#include <fcntl.h> 51#include <paths.h> 52#include <stdio.h> 53#include <string.h> 54#include <time.h> 55#include <unistd.h> 56 57#if __STDC__ 58#include <stdarg.h> 59#else 60#include <varargs.h> 61#endif 62 63static int LogFile = -1; /* fd for log */ 64static int connected; /* have done connect */ 65static int opened; /* have done openlog() */ 66static int LogStat = 0; /* status bits, set by openlog() */ 67static const char *LogTag = NULL; /* string to tag the entry with */ 68static int LogFacility = LOG_USER; /* default facility code */ 69static int LogMask = 0xff; /* mask of priorities to be logged */ 70extern char *__progname; /* Program name, from crt0. */ 71 72static void disconnectlog __P((void)); /* disconnect from syslogd */ 73static void connectlog __P((void)); /* (re)connect to syslogd */ 74 75/* 76 * Format of the magic cookie passed through the stdio hook 77 */ 78struct bufcookie { 79 char *base; /* start of buffer */ 80 int left; 81}; 82 83/* 84 * stdio write hook for writing to a static string buffer 85 * XXX: Maybe one day, dynamically allocate it so that the line length 86 * is `unlimited'. 87 */ 88static 89int writehook(cookie, buf, len) 90 void *cookie; /* really [struct bufcookie *] */ 91 char *buf; /* characters to copy */ 92 int len; /* length to copy */ 93{ 94 struct bufcookie *h; /* private `handle' */ 95 96 h = (struct bufcookie *)cookie; 97 if (len > h->left) { 98 /* clip in case of wraparound */ 99 len = h->left; 100 } 101 if (len > 0) { 102 (void)memcpy(h->base, buf, len); /* `write' it. */ 103 h->base += len; 104 h->left -= len; 105 } 106 return 0; 107} 108 109/* 110 * syslog, vsyslog -- 111 * print message on log file; output is intended for syslogd(8). 112 */ 113void 114#if __STDC__ 115syslog(int pri, const char *fmt, ...) 116#else 117syslog(pri, fmt, va_alist) 118 int pri; 119 char *fmt; 120 va_dcl 121#endif 122{ 123 va_list ap; 124 125#if __STDC__ 126 va_start(ap, fmt); 127#else 128 va_start(ap); 129#endif 130 vsyslog(pri, fmt, ap); 131 va_end(ap); 132} 133 134void 135vsyslog(pri, fmt, ap) 136 int pri; 137 register const char *fmt; 138 va_list ap; 139{ 140 register int cnt; 141 register char ch, *p; 142 time_t now; 143 int fd, saved_errno; 144 char *stdp, tbuf[2048], fmt_cpy[1024]; 145 FILE *fp, *fmt_fp; 146 struct bufcookie tbuf_cookie; 147 struct bufcookie fmt_cookie; 148 149#define INTERNALLOG LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID 150 /* Check for invalid bits. */ 151 if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) { 152 syslog(INTERNALLOG, 153 "syslog: unknown facility/priority: %x", pri); 154 pri &= LOG_PRIMASK|LOG_FACMASK; 155 } 156 157 /* Check priority against setlogmask values. */ 158 if (!(LOG_MASK(LOG_PRI(pri)) & LogMask)) 159 return; 160 161 saved_errno = errno; 162 163 /* Set default facility if none specified. */ 164 if ((pri & LOG_FACMASK) == 0) 165 pri |= LogFacility; 166 167 /* Create the primary stdio hook */ 168 tbuf_cookie.base = tbuf; 169 tbuf_cookie.left = sizeof(tbuf); 170 fp = fwopen(&tbuf_cookie, writehook); 171 if (fp == NULL) 172 return; 173 174 /* Build the message. */ 175 (void)time(&now); 176 (void)fprintf(fp, "<%d>", pri); 177 (void)fprintf(fp, "%.15s ", ctime(&now) + 4); 178 if (LogStat & LOG_PERROR) { 179 /* Transfer to string buffer */ 180 (void)fflush(fp); 181 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left); 182 } 183 if (LogTag == NULL) 184 LogTag = __progname; 185 if (LogTag != NULL) 186 (void)fprintf(fp, "%s", LogTag); 187 if (LogStat & LOG_PID) 188 (void)fprintf(fp, "[%d]", getpid()); 189 if (LogTag != NULL) { 190 (void)fprintf(fp, ": "); 191 } 192 193 /* Check to see if we can skip expanding the %m */ 194 if (strstr(fmt, "%m")) { 195 196 /* Create the second stdio hook */ 197 fmt_cookie.base = fmt_cpy; 198 fmt_cookie.left = sizeof(fmt_cpy) - 1; 199 fmt_fp = fwopen(&fmt_cookie, writehook); 200 if (fmt_fp == NULL) { 201 fclose(fp); 202 return; 203 } 204 205 /* Substitute error message for %m. */ 206 for ( ; (ch = *fmt); ++fmt) 207 if (ch == '%' && fmt[1] == 'm') { 208 ++fmt; 209 fputs(strerror(saved_errno), fmt_fp); 210 } else 211 fputc(ch, fmt_fp); 212 213 /* Null terminate if room */ 214 fputc(0, fmt_fp); 215 fclose(fmt_fp); 216 217 /* Guarantee null termination */ 218 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0'; 219 220 fmt = fmt_cpy; 221 } 222 223 (void)vfprintf(fp, fmt, ap); 224 (void)fclose(fp); 225 226 cnt = sizeof(tbuf) - tbuf_cookie.left; 227 228 /* Output to stderr if requested. */ 229 if (LogStat & LOG_PERROR) { 230 struct iovec iov[2]; 231 register struct iovec *v = iov; 232 233 v->iov_base = stdp; 234 v->iov_len = cnt - (stdp - tbuf); 235 ++v; 236 v->iov_base = "\n"; 237 v->iov_len = 1; 238 (void)writev(STDERR_FILENO, iov, 2); 239 } 240 241 /* Get connected, output the message to the local logger. */ 242 if (!opened) 243 openlog(LogTag, LogStat | LOG_NDELAY, 0); 244 connectlog(); 245 if (send(LogFile, tbuf, cnt, 0) >= 0) 246 return; 247 248 /* 249 * If the send() failed, the odds are syslogd was restarted. 250 * Make one (only) attempt to reconnect to /dev/log. 251 */ 252 disconnectlog(); 253 connectlog(); 254 if (send(LogFile, tbuf, cnt, 0) >= 0) 255 return; 256 257 /* 258 * Output the message to the console; don't worry about blocking, 259 * if console blocks everything will. Make sure the error reported 260 * is the one from the syslogd failure. 261 */ 262 if (LogStat & LOG_CONS && 263 (fd = open(_PATH_CONSOLE, O_WRONLY, 0)) >= 0) { 264 struct iovec iov[2]; 265 register struct iovec *v = iov; 266 267 p = strchr(tbuf, '>') + 1; 268 v->iov_base = p; 269 v->iov_len = cnt - (p - tbuf); 270 ++v; 271 v->iov_base = "\r\n"; 272 v->iov_len = 2; 273 (void)writev(fd, iov, 2); 274 (void)close(fd); 275 } 276} 277static void 278disconnectlog() 279{ 280 /* 281 * If the user closed the FD and opened another in the same slot, 282 * that's their problem. They should close it before calling on 283 * system services. 284 */ 285 if (LogFile != -1) { 286 close(LogFile); 287 LogFile = -1; 288 } 289 connected = 0; /* retry connect */ 290} 291 292static void 293connectlog() 294{ 295 struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ 296 297 if (LogFile == -1) { 298 if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) 299 return; 300 (void)fcntl(LogFile, F_SETFD, 1); 301 } 302 if (LogFile != -1 && !connected) { 303 SyslogAddr.sun_len = sizeof(SyslogAddr); 304 SyslogAddr.sun_family = AF_UNIX; 305 (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, 306 sizeof SyslogAddr.sun_path - 1); 307 SyslogAddr.sun_path[sizeof SyslogAddr.sun_path - 1] = '\0'; 308 connected = connect(LogFile, (struct sockaddr *)&SyslogAddr, 309 sizeof(SyslogAddr)) != -1; 310 311 if (!connected) { 312 /* 313 * Try the old "/dev/log" path, for backward 314 * compatibility. 315 */ 316 (void)strncpy(SyslogAddr.sun_path, _PATH_OLDLOG, 317 sizeof SyslogAddr.sun_path - 1); 318 connected = connect(LogFile, 319 (struct sockaddr *)&SyslogAddr, 320 sizeof(SyslogAddr)) != -1; 321 } 322 323 if (!connected) { 324 (void)close(LogFile); 325 LogFile = -1; 326 } 327 } 328} 329 330void 331openlog(ident, logstat, logfac) 332 const char *ident; 333 int logstat, logfac; 334{ 335 if (ident != NULL) 336 LogTag = ident; 337 LogStat = logstat; 338 if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0) 339 LogFacility = logfac; 340 341 if (LogStat & LOG_NDELAY) /* open immediately */ 342 connectlog(); 343 344 opened = 1; /* ident and facility has been set */ 345} 346 347void 348closelog() 349{ 350 (void)close(LogFile); 351 LogFile = -1; 352 connected = 0; 353} 354 355/* setlogmask -- set the log mask level */ 356int 357setlogmask(pmask) 358 int pmask; 359{ 360 int omask; 361 362 omask = LogMask; 363 if (pmask != 0) 364 LogMask = pmask; 365 return (omask); 366} 367