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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)syslog.c    8.4 (Berkeley) 3/18/94";
  32 #endif /* LIBC_SCCS and not lint */
  33
  34 #include <sys/types.h>
  35 #include <sys/socket.h>
  36 #include <sys/syslog.h>
  37 #include <sys/uio.h>
  38 #include <netdb.h>
  39
  40 #include <errno.h>
  41 #include <fcntl.h>
  42 #include <paths.h>
  43 #include <stdio.h>
  44 #include <string.h>
  45 #include <time.h>
  46 #include <unistd.h>
  47 #include <stdlib.h>
  48 #include <bits/libc-lock.h>
  49 #include <signal.h>
  50
  51 #if __STDC__
  52 #include <stdarg.h>
  53 #else
  54 #include <varargs.h>
  55 #endif
  56
  57 #ifdef USE_IN_LIBIO
  58 # include <libio/iolibio.h>
  59 # define ftell(s) _IO_ftell (s)
  60 #endif
  61
  62 static int      LogType = SOCK_DGRAM;   /* type of socket connection */
  63 static int      LogFile = -1;           /* fd for log */
  64 static int      connected;              /* have done connect */
  65 static int      LogStat;                /* status bits, set by openlog() */
  66 static const char *LogTag;              /* 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 extern char     *__progname;            /* Program name, from crt0. */
  70
  71 /* Define the lock.  */
  72 __libc_lock_define_initialized (static, syslog_lock)
  73
  74 static void openlog_internal(const char *, int, int) internal_function;
  75 static void closelog_internal(void);
  76 static void sigpipe_handler (int);
  77 #ifdef _LIBC_REENTRANT
  78 static void cancel_handler (void *);
  79 #endif
  80
  81 /*
  82  * syslog, vsyslog --
  83  *      print message on log file; output is intended for syslogd(8).
  84  */
  85 void
  86 #if __STDC__
  87 syslog(int pri, const char *fmt, ...)
  88 #else
  89 syslog(pri, fmt, va_alist)
  90         int pri;
  91         char *fmt;
  92         va_dcl
  93 #endif
  94 {
  95         va_list ap;
  96
  97 #if __STDC__
  98         va_start(ap, fmt);
  99 #else
 100         va_start(ap);
 101 #endif
 102         vsyslog(pri, fmt, ap);
 103         va_end(ap);
 104 }
 105
 106 void
 107 vsyslog(pri, fmt, ap)
 108         int pri;
 109         register const char *fmt;
 110         va_list ap;
 111 {
 112         struct tm now_tm;
 113         time_t now;
 114         int fd;
 115         FILE *f;
 116         char *buf = 0;
 117         size_t bufsize = 0;
 118         size_t prioff, msgoff;
 119         struct sigaction action, oldaction;
 120         struct sigaction *oldaction_ptr = NULL;
 121         int sigpipe;
 122         int saved_errno = errno;
 123
 124 #define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 125         /* Check for invalid bits. */
 126         if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
 127                 syslog(INTERNALLOG,
 128                     "syslog: unknown facility/priority: %x", pri);
 129                 pri &= LOG_PRIMASK|LOG_FACMASK;
 130         }
 131
 132         /* Check priority against setlogmask values. */
 133         if ((LOG_MASK (LOG_PRI (pri)) & LogMask) == 0)
 134                 return;
 135
 136         /* Set default facility if none specified. */
 137         if ((pri & LOG_FACMASK) == 0)
 138                 pri |= LogFacility;
 139
 140         /* Build the message in a memory-buffer stream.  */
 141         f = open_memstream (&buf, &bufsize);
 142         prioff = fprintf (f, "<%d>", pri);
 143         (void) time (&now);
 144 #ifdef USE_IN_LIBIO
 145         f->_IO_write_ptr += strftime (f->_IO_write_ptr,
 146                                       f->_IO_write_end - f->_IO_write_ptr,
 147                                       "%h %e %T ",
 148                                       __localtime_r (&now, &now_tm));
 149 #else
 150         f->__bufp += strftime (f->__bufp, f->__put_limit - f->__bufp,
 151                                "%h %e %T ", __localtime_r (&now, &now_tm));
 152 #endif
 153         msgoff = ftell (f);
 154         if (LogTag == NULL)
 155           LogTag = __progname;
 156         if (LogTag != NULL)
 157           fputs_unlocked (LogTag, f);
 158         if (LogStat & LOG_PID)
 159           fprintf (f, "[%d]", __getpid ());
 160         if (LogTag != NULL)
 161           putc_unlocked (':', f), putc_unlocked (' ', f);
 162
 163         /* Restore errno for %m format.  */
 164         __set_errno (saved_errno);
 165
 166         /* We have the header.  Print the user's format into the buffer.  */
 167         vfprintf (f, fmt, ap);
 168
 169         /* Close the memory stream; this will finalize the data
 170            into a malloc'd buffer in BUF.  */
 171         fclose (f);
 172
 173         /* Output to stderr if requested. */
 174         if (LogStat & LOG_PERROR) {
 175                 struct iovec iov[2];
 176                 register struct iovec *v = iov;
 177
 178                 v->iov_base = buf + msgoff;
 179                 v->iov_len = bufsize - msgoff;
 180                 /* Append a newline if necessary.  */
 181                 if (buf[bufsize - 1] != '\n')
 182                   {
 183                     ++v;
 184                     v->iov_base = (char *) "\n";
 185                     v->iov_len = 1;
 186                   }
 187                 (void)__writev(STDERR_FILENO, iov, v - iov + 1);
 188         }
 189
 190         /* Prepare for multiple users.  We have to take care: open and
 191            write are cancellation points.  */
 192         __libc_cleanup_region_start ((void (*) (void *)) cancel_handler,
 193                                      &oldaction_ptr);
 194         __libc_lock_lock (syslog_lock);
 195
 196         /* Prepare for a broken connection.  */
 197         memset (&action, 0, sizeof (action));
 198         action.sa_handler = sigpipe_handler;
 199         sigemptyset (&action.sa_mask);
 200         sigpipe = __sigaction (SIGPIPE, &action, &oldaction);
 201         if (sigpipe == 0)
 202           oldaction_ptr = &oldaction;
 203
 204         /* Get connected, output the message to the local logger. */
 205         if (!connected)
 206                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 207
 208         /* If we have a SOCK_STREAM connection, also send ASCII NUL as
 209            a record terminator.  */
 210         if (LogType == SOCK_STREAM)
 211           ++bufsize;
 212
 213         if (!connected || __send(LogFile, buf, bufsize, 0) < 0)
 214           {
 215             closelog_internal ();       /* attempt re-open next time */
 216             /*
 217              * Output the message to the console; don't worry about blocking,
 218              * if console blocks everything will.  Make sure the error reported
 219              * is the one from the syslogd failure.
 220              */
 221             if (LogStat & LOG_CONS &&
 222                 (fd = __open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) >= 0)
 223               {
 224                 dprintf (fd, "%s\r\n", buf + msgoff);
 225                 (void)__close(fd);
 226               }
 227           }
 228
 229         if (sigpipe == 0)
 230                 __sigaction (SIGPIPE, &oldaction, (struct sigaction *) NULL);
 231
 232         /* End of critical section.  */
 233         __libc_cleanup_region_end (0);
 234         __libc_lock_unlock (syslog_lock);
 235
 236         free (buf);
 237 }
 238
 239 static struct sockaddr SyslogAddr;      /* AF_UNIX address of local logger */
 240
 241 static void
 242 internal_function
 243 openlog_internal(const char *ident, int logstat, int logfac)
 244 {
 245         if (ident != NULL)
 246                 LogTag = ident;
 247         LogStat = logstat;
 248         if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
 249                 LogFacility = logfac;
 250
 251         while (1) {
 252                 if (LogFile == -1) {
 253                         SyslogAddr.sa_family = AF_UNIX;
 254                         (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
 255                                       sizeof(SyslogAddr.sa_data));
 256                         if (LogStat & LOG_NDELAY) {
 257                                 if ((LogFile = __socket(AF_UNIX, LogType, 0))
 258                                     == -1)
 259                                         return;
 260                                 (void)__fcntl(LogFile, F_SETFD, 1);
 261                         }
 262                 }
 263                 if (LogFile != -1 && !connected)
 264                 {
 265                         int old_errno = errno;
 266                         if (__connect(LogFile, &SyslogAddr, sizeof(SyslogAddr))
 267                             == -1)
 268                         {
 269                                 int saved_errno = errno;
 270                                 (void)__close(LogFile);
 271                                 LogFile = -1;
 272                                 if (LogType == SOCK_DGRAM
 273                                     && saved_errno == EPROTOTYPE)
 274                                 {
 275                                         /* retry with next SOCK_STREAM: */
 276                                         LogType = SOCK_STREAM;
 277                                         __set_errno (old_errno);
 278                                         continue;
 279                                 }
 280                         } else
 281                                 connected = 1;
 282                 }
 283                 break;
 284         }
 285 }
 286
 287 void
 288 openlog (const char *ident, int logstat, int logfac)
 289 {
 290   /* Protect against multiple users.  */
 291   __libc_cleanup_region_start ((void (*) __P ((void *))) __libc_mutex_unlock,
 292                                &syslog_lock);
 293   __libc_lock_lock (syslog_lock);
 294
 295   openlog_internal (ident, logstat, logfac);
 296
 297   /* Free the lock.  */
 298   __libc_cleanup_region_end (1);
 299 }
 300
 301 static void
 302 sigpipe_handler (int signo)
 303 {
 304   closelog_internal ();
 305 }
 306
 307 static void
 308 closelog_internal()
 309 {
 310   if (!connected)
 311     return;
 312
 313   __close (LogFile);
 314   LogFile = -1;
 315   connected = 0;
 316 }
 317
 318 void
 319 closelog ()
 320 {
 321   /* Protect against multiple users.  */
 322   __libc_cleanup_region_start ((void (*) __P ((void *))) __libc_mutex_unlock,
 323                                &syslog_lock);
 324   __libc_lock_lock (syslog_lock);
 325
 326   closelog_internal ();
 327   LogTag = NULL;
 328   LogType = SOCK_DGRAM; /* this is the default */
 329
 330   /* Free the lock.  */
 331   __libc_cleanup_region_end (1);
 332 }
 333
 334 #ifdef _LIBC_REENTRANT
 335 static void
 336 cancel_handler (void *ptr)
 337 {
 338   /* Restore the old signal handler.  */
 339   struct sigaction *oldaction = *((struct sigaction **) ptr);
 340
 341   if (oldaction != (struct sigaction *) NULL)
 342     __sigaction (SIGPIPE, oldaction, (struct sigaction *) NULL);
 343
 344   /* Free the lock.  */
 345   __libc_lock_unlock (syslog_lock);
 346 }
 347 #endif
 348
 349 /* setlogmask -- set the log mask level */
 350 int
 351 setlogmask(pmask)
 352         int pmask;
 353 {
 354         int omask;
 355
 356         omask = LogMask;
 357         if (pmask != 0)
 358                 LogMask = pmask;
 359         return (omask);
 360 }