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