misc/syslog.c

   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    8.4 (Berkeley) 3/18/94";
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include <sys/types.h>
  39 #include <sys/socket.h>
  40 #include <sys/syslog.h>
  41 #include <sys/uio.h>
  42 #include <netdb.h>
  43
  44 #include <errno.h>
  45 #include <fcntl.h>
  46 #include <paths.h>
  47 #include <stdio.h>
  48 #include <string.h>
  49 #include <time.h>
  50 #include <unistd.h>
  51 #include <stdlib.h>
  52 #include <libc-lock.h>
  53 #include <signal.h>
  54
  55 #if __STDC__
  56 #include <stdarg.h>
  57 #else
  58 #include <varargs.h>
  59 #endif
  60
  61 static int      LogType = SOCK_DGRAM;   /* type of socket connection */
  62 static int      LogFile = -1;           /* fd for log */
  63 static int      connected;              /* have done connect */
  64 static int      LogStat = 0;            /* status bits, set by openlog() */
  65 static const char *LogTag = NULL;       /* string to tag the entry with */
  66 static int      LogFacility = LOG_USER; /* default facility code */
  67 static int      LogMask = 0xff;         /* mask of priorities to be logged */
  68 extern char     *__progname;            /* Program name, from crt0. */
  69
  70 /* Define the lock.  */
  71 __libc_lock_define_initialized (static, syslog_lock)
  72
  73 static void openlog_internal(const char *, int, int);
  74 static void closelog_internal(void);
  75 static void sigpipe_handler (int);
  76 #ifdef _LIBC_REENTRANT
  77 static void cancel_handler (void *);
  78 #endif
  79
  80 /*
  81  * syslog, vsyslog --
  82  *      print message on log file; output is intended for syslogd(8).
  83  */
  84 void
  85 #if __STDC__
  86 syslog(int pri, const char *fmt, ...)
  87 #else
  88 syslog(pri, fmt, va_alist)
  89         int pri;
  90         char *fmt;
  91         va_dcl
  92 #endif
  93 {
  94         va_list ap;
  95
  96 #if __STDC__
  97         va_start(ap, fmt);
  98 #else
  99         va_start(ap);
 100 #endif
 101         vsyslog(pri, fmt, ap);
 102         va_end(ap);
 103 }
 104
 105 void
 106 vsyslog(pri, fmt, ap)
 107         int pri;
 108         register const char *fmt;
 109         va_list ap;
 110 {
 111         struct tm now_tm;
 112         time_t now;
 113         int fd;
 114         FILE *f;
 115         char *buf = 0;
 116         size_t bufsize = 0;
 117         size_t prioff, msgoff;
 118         struct sigaction action, oldaction;
 119         struct sigaction *oldaction_ptr = NULL;
 120         int sigpipe;
 121
 122 #define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 123         /* Check for invalid bits. */
 124         if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
 125                 syslog(INTERNALLOG,
 126                     "syslog: unknown facility/priority: %x", pri);
 127                 pri &= LOG_PRIMASK|LOG_FACMASK;
 128         }
 129
 130         /* Check priority against setlogmask values. */
 131         if (!LOG_MASK(LOG_PRI(pri)) & LogMask)
 132                 return;
 133
 134         /* Set default facility if none specified. */
 135         if ((pri & LOG_FACMASK) == 0)
 136                 pri |= LogFacility;
 137
 138         /* Build the message in a memory-buffer stream.  */
 139         f = open_memstream (&buf, &bufsize);
 140         prioff = fprintf (f, "<%d>", pri);
 141         (void) time (&now);
 142 #ifdef USE_IN_LIBIO
 143         f->_IO_write_ptr += strftime (f->_IO_write_ptr,
 144                                       f->_IO_write_end - f->_IO_write_ptr,
 145                                       "%h %e %T ",
 146                                       __localtime_r (&now, &now_tm));
 147 #else
 148         f->__bufp += strftime (f->__bufp, f->__put_limit - f->__bufp,
 149                                "%h %e %T ", __localtime_r (&now, &now_tm));
 150 #endif
 151         msgoff = ftell (f);
 152         if (LogTag == NULL)
 153           LogTag = __progname;
 154         if (LogTag != NULL)
 155           fputs (LogTag, f);
 156         if (LogStat & LOG_PID)
 157           fprintf (f, "[%d]", getpid ());
 158         if (LogTag != NULL)
 159           putc (':', f), putc (' ', f);
 160
 161         /* We have the header.  Print the user's format into the buffer.  */
 162         vfprintf (f, fmt, ap);
 163
 164         /* Close the memory stream; this will finalize the data
 165            into a malloc'd buffer in BUF.  */
 166         fclose (f);
 167
 168         /* Output to stderr if requested. */
 169         if (LogStat & LOG_PERROR) {
 170                 struct iovec iov[2];
 171                 register struct iovec *v = iov;
 172
 173                 v->iov_base = buf + msgoff;
 174                 v->iov_len = bufsize - msgoff;
 175                 ++v;
 176                 v->iov_base = (char *) "\n";
 177                 v->iov_len = 1;
 178                 (void)writev(STDERR_FILENO, iov, 2);
 179         }
 180
 181         /* Prepare for multiple users.  We have to take care: open and
 182            write are cancellation points.  */
 183         __libc_cleanup_region_start ((void (*) (void *)) cancel_handler,
 184                                      &oldaction_ptr);
 185         __libc_lock_lock (syslog_lock);
 186
 187         /* Prepare for a broken connection.  */
 188         memset (&action, 0, sizeof (action));
 189         action.sa_handler = sigpipe_handler;
 190         sigemptyset (&action.sa_mask);
 191         sigpipe = sigaction (SIGPIPE, &action, &oldaction);
 192         if (sigpipe == 0)
 193           oldaction_ptr = &oldaction;
 194
 195         /* Get connected, output the message to the local logger. */
 196         if (!connected)
 197                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 198
 199         /* If we have a SOCK_STREAM connection, also send ASCII NUL as
 200            a record terminator.  */
 201         if (LogType == SOCK_STREAM)
 202           ++bufsize;
 203
 204         if (!connected || __send(LogFile, buf, bufsize, 0) < 0)
 205           {
 206             closelog_internal ();       /* attempt re-open next time */
 207             /*
 208              * Output the message to the console; don't worry about blocking,
 209              * if console blocks everything will.  Make sure the error reported
 210              * is the one from the syslogd failure.
 211              */
 212             if (LogStat & LOG_CONS &&
 213                 (fd = open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) >= 0)
 214               {
 215                 dprintf (fd, "%s\r\n", buf + msgoff);
 216                 (void)close(fd);
 217               }
 218           }
 219
 220         if (sigpipe == 0)
 221                 sigaction (SIGPIPE, &oldaction, (struct sigaction *) NULL);
 222
 223         /* End of critical section.  */
 224         __libc_cleanup_region_end (0);
 225         __libc_lock_unlock (syslog_lock);
 226
 227         free (buf);
 228 }
 229
 230 static struct sockaddr SyslogAddr;      /* AF_UNIX address of local logger */
 231
 232 static void
 233 openlog_internal(const char *ident, int logstat, int logfac)
 234 {
 235         if (ident != NULL)
 236                 LogTag = ident;
 237         LogStat = logstat;
 238         if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
 239                 LogFacility = logfac;
 240
 241         while (1) {
 242                 if (LogFile == -1) {
 243                         SyslogAddr.sa_family = AF_UNIX;
 244                         (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
 245                                       sizeof(SyslogAddr.sa_data));
 246                         if (LogStat & LOG_NDELAY) {
 247                                 if ((LogFile = socket(AF_UNIX, LogType, 0))
 248                                     == -1)
 249                                         return;
 250                                 (void)fcntl(LogFile, F_SETFD, 1);
 251                         }
 252                 }
 253                 if (LogFile != -1 && !connected)
 254                 {
 255                         int old_errno = errno;
 256                         if (__connect(LogFile, &SyslogAddr, sizeof(SyslogAddr))
 257                             == -1)
 258                         {
 259                                 int saved_errno = errno;
 260                                 (void)close(LogFile);
 261                                 LogFile = -1;
 262                                 if (LogType == SOCK_DGRAM
 263                                     && saved_errno == EPROTOTYPE)
 264                                 {
 265                                         /* retry with next SOCK_STREAM: */
 266                                         LogType = SOCK_STREAM;
 267                                         __set_errno (old_errno);
 268                                         continue;
 269                                 }
 270                         } else
 271                                 connected = 1;
 272                 }
 273                 break;
 274         }
 275 }
 276
 277 void
 278 openlog (const char *ident, int logstat, int logfac)
 279 {
 280   /* Protect against multiple users.  */
 281   __libc_cleanup_region_start ((void (*) __P ((void *))) __libc_mutex_unlock,
 282                                &syslog_lock);
 283   __libc_lock_lock (syslog_lock);
 284
 285   openlog_internal (ident, logstat, logfac);
 286
 287   /* Free the lock.  */
 288   __libc_cleanup_region_end (1);
 289 }
 290
 291 static void
 292 sigpipe_handler (int signo)
 293 {
 294         closelog_internal();
 295 }
 296
 297 static void
 298 closelog_internal()
 299 {
 300         if (!connected)
 301                 return;
 302         (void)close(LogFile);
 303         LogFile = -1;
 304         connected = 0;
 305 }
 306
 307 void
 308 closelog ()
 309 {
 310   /* Protect against multiple users.  */
 311   __libc_cleanup_region_start ((void (*) __P ((void *))) __libc_mutex_unlock,
 312                                &syslog_lock);
 313   __libc_lock_lock (syslog_lock);
 314
 315   closelog_internal ();
 316
 317   /* Free the lock.  */
 318   __libc_cleanup_region_end (1);
 319 }
 320
 321 #ifdef _LIBC_REENTRANT
 322 static void
 323 cancel_handler (void *ptr)
 324 {
 325   /* Restore the old signal handler.  */
 326   struct sigaction *oldaction = *((struct sigaction **) ptr);
 327
 328   if (oldaction != (struct sigaction *) NULL)
 329     sigaction (SIGPIPE, oldaction, (struct sigaction *) NULL);
 330
 331   /* Free the lock.  */
 332   __libc_lock_unlock (syslog_lock);
 333 }
 334 #endif
 335
 336 /* setlogmask -- set the log mask level */
 337 int
 338 setlogmask(pmask)
 339         int pmask;
 340 {
 341         int omask;
 342
 343         omask = LogMask;
 344         if (pmask != 0)
 345                 LogMask = pmask;
 346         return (omask);
 347 }