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         char failbuf[3 * sizeof (pid_t) + sizeof "out of memory []"];
 124
 125 #define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 126         /* Check for invalid bits. */
 127         if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
 128                 syslog(INTERNALLOG,
 129                     "syslog: unknown facility/priority: %x", pri);
 130                 pri &= LOG_PRIMASK|LOG_FACMASK;
 131         }
 132
 133         /* Check priority against setlogmask values. */
 134         if ((LOG_MASK (LOG_PRI (pri)) & LogMask) == 0)
 135                 return;
 136
 137         /* Set default facility if none specified. */
 138         if ((pri & LOG_FACMASK) == 0)
 139                 pri |= LogFacility;
 140
 141         /* Build the message in a memory-buffer stream.  */
 142         f = open_memstream (&buf, &bufsize);
 143         if (f == NULL)
 144           {
 145             /* We cannot get a stream.  There is not much we can do but
 146                emitting an error messages.  */
 147             char numbuf[3 * sizeof (pid_t)];
 148             char *nump;
 149             char *endp = __stpcpy (failbuf, "out of memory [");
 150             pid_t pid = __getpid ();
 151
 152             nump = numbuf + sizeof (numbuf);
 153             /* The PID can never be zero.  */
 154             do
 155               *--nump = '0' + pid % 10;
 156             while ((pid /= 10) != 0);
 157
 158             endp = __mempcpy (endp, nump, (nump + sizeof (numbuf)) - nump);
 159             *endp++ = ']';
 160             *endp = '\0';
 161             buf = failbuf;
 162             bufsize = endp - failbuf;
 163             msgoff = 0;
 164           }
 165         else
 166           {
 167             prioff = fprintf (f, "<%d>", pri);
 168             (void) time (&now);
 169 #ifdef USE_IN_LIBIO
 170             f->_IO_write_ptr += strftime (f->_IO_write_ptr,
 171                                           f->_IO_write_end - f->_IO_write_ptr,
 172                                           "%h %e %T ",
 173                                           __localtime_r (&now, &now_tm));
 174 #else
 175             f->__bufp += strftime (f->__bufp, f->__put_limit - f->__bufp,
 176                                    "%h %e %T ", __localtime_r (&now, &now_tm));
 177 #endif
 178             msgoff = ftell (f);
 179             if (LogTag == NULL)
 180               LogTag = __progname;
 181             if (LogTag != NULL)
 182               fputs_unlocked (LogTag, f);
 183             if (LogStat & LOG_PID)
 184               fprintf (f, "[%d]", __getpid ());
 185             if (LogTag != NULL)
 186               putc_unlocked (':', f), putc_unlocked (' ', f);
 187
 188             /* Restore errno for %m format.  */
 189             __set_errno (saved_errno);
 190
 191             /* We have the header.  Print the user's format into the
 192                buffer.  */
 193             vfprintf (f, fmt, ap);
 194
 195             /* Close the memory stream; this will finalize the data
 196                into a malloc'd buffer in BUF.  */
 197             fclose (f);
 198           }
 199
 200         /* Output to stderr if requested. */
 201         if (LogStat & LOG_PERROR) {
 202                 struct iovec iov[2];
 203                 register struct iovec *v = iov;
 204
 205                 v->iov_base = buf + msgoff;
 206                 v->iov_len = bufsize - msgoff;
 207                 /* Append a newline if necessary.  */
 208                 if (buf[bufsize - 1] != '\n')
 209                   {
 210                     ++v;
 211                     v->iov_base = (char *) "\n";
 212                     v->iov_len = 1;
 213                   }
 214                 (void)__writev(STDERR_FILENO, iov, v - iov + 1);
 215         }
 216
 217         /* Prepare for multiple users.  We have to take care: open and
 218            write are cancellation points.  */
 219         __libc_cleanup_region_start (1, (void (*) (void *)) cancel_handler,
 220                                      &oldaction_ptr);
 221         __libc_lock_lock (syslog_lock);
 222
 223         /* Prepare for a broken connection.  */
 224         memset (&action, 0, sizeof (action));
 225         action.sa_handler = sigpipe_handler;
 226         sigemptyset (&action.sa_mask);
 227         sigpipe = __sigaction (SIGPIPE, &action, &oldaction);
 228         if (sigpipe == 0)
 229           oldaction_ptr = &oldaction;
 230
 231         /* Get connected, output the message to the local logger. */
 232         if (!connected)
 233                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 234
 235         /* If we have a SOCK_STREAM connection, also send ASCII NUL as
 236            a record terminator.  */
 237         if (LogType == SOCK_STREAM)
 238           ++bufsize;
 239
 240         if (!connected || __send(LogFile, buf, bufsize, 0) < 0)
 241           {
 242             if (connected)
 243               {
 244                 /* Try to reopen the syslog connection.  Maybe it went
 245                    down.  */
 246                 closelog_internal ();
 247                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 248               }
 249
 250             if (!connected || __send(LogFile, buf, bufsize, 0) < 0)
 251               {
 252                 closelog_internal ();   /* attempt re-open next time */
 253                 /*
 254                  * Output the message to the console; don't worry
 255                  * about blocking, if console blocks everything will.
 256                  * Make sure the error reported is the one from the
 257                  * syslogd failure.
 258                  */
 259                 if (LogStat & LOG_CONS &&
 260                     (fd = __open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) >= 0)
 261                   {
 262                     dprintf (fd, "%s\r\n", buf + msgoff);
 263                     (void)__close(fd);
 264                   }
 265               }
 266           }
 267
 268         if (sigpipe == 0)
 269                 __sigaction (SIGPIPE, &oldaction, (struct sigaction *) NULL);
 270
 271         /* End of critical section.  */
 272         __libc_cleanup_region_end (0);
 273         __libc_lock_unlock (syslog_lock);
 274
 275         free (buf);
 276 }
 277
 278 static struct sockaddr SyslogAddr;      /* AF_UNIX address of local logger */
 279
 280 static void
 281 internal_function
 282 openlog_internal(const char *ident, int logstat, int logfac)
 283 {
 284         if (ident != NULL)
 285                 LogTag = ident;
 286         LogStat = logstat;
 287         if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
 288                 LogFacility = logfac;
 289
 290         while (1) {
 291                 if (LogFile == -1) {
 292                         SyslogAddr.sa_family = AF_UNIX;
 293                         (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
 294                                       sizeof(SyslogAddr.sa_data));
 295                         if (LogStat & LOG_NDELAY) {
 296                                 if ((LogFile = __socket(AF_UNIX, LogType, 0))
 297                                     == -1)
 298                                         return;
 299                                 (void)__fcntl(LogFile, F_SETFD, 1);
 300                         }
 301                 }
 302                 if (LogFile != -1 && !connected)
 303                 {
 304                         int old_errno = errno;
 305                         if (__connect(LogFile, &SyslogAddr, sizeof(SyslogAddr))
 306                             == -1)
 307                         {
 308                                 int saved_errno = errno;
 309                                 (void)__close(LogFile);
 310                                 LogFile = -1;
 311                                 if (LogType == SOCK_DGRAM
 312                                     && saved_errno == EPROTOTYPE)
 313                                 {
 314                                         /* retry with next SOCK_STREAM: */
 315                                         LogType = SOCK_STREAM;
 316                                         __set_errno (old_errno);
 317                                         continue;
 318                                 }
 319                         } else
 320                                 connected = 1;
 321                 }
 322                 break;
 323         }
 324 }
 325
 326 void
 327 openlog (const char *ident, int logstat, int logfac)
 328 {
 329   /* Protect against multiple users.  */
 330   __libc_cleanup_region_start (1,
 331                                (void (*) __P ((void *))) __libc_mutex_unlock,
 332                                &syslog_lock);
 333   __libc_lock_lock (syslog_lock);
 334
 335   openlog_internal (ident, logstat, logfac);
 336
 337   /* Free the lock.  */
 338   __libc_cleanup_region_end (1);
 339 }
 340
 341 static void
 342 sigpipe_handler (int signo)
 343 {
 344   closelog_internal ();
 345 }
 346
 347 static void
 348 closelog_internal()
 349 {
 350   if (!connected)
 351     return;
 352
 353   __close (LogFile);
 354   LogFile = -1;
 355   connected = 0;
 356 }
 357
 358 void
 359 closelog ()
 360 {
 361   /* Protect against multiple users.  */
 362   __libc_cleanup_region_start (1,
 363                                (void (*) __P ((void *))) __libc_mutex_unlock,
 364                                &syslog_lock);
 365   __libc_lock_lock (syslog_lock);
 366
 367   closelog_internal ();
 368   LogTag = NULL;
 369   LogType = SOCK_DGRAM; /* this is the default */
 370
 371   /* Free the lock.  */
 372   __libc_cleanup_region_end (1);
 373 }
 374
 375 #ifdef _LIBC_REENTRANT
 376 static void
 377 cancel_handler (void *ptr)
 378 {
 379   /* Restore the old signal handler.  */
 380   struct sigaction *oldaction = *((struct sigaction **) ptr);
 381
 382   if (oldaction != (struct sigaction *) NULL)
 383     __sigaction (SIGPIPE, oldaction, (struct sigaction *) NULL);
 384
 385   /* Free the lock.  */
 386   __libc_lock_unlock (syslog_lock);
 387 }
 388 #endif
 389
 390 /* setlogmask -- set the log mask level */
 391 int
 392 setlogmask(pmask)
 393         int pmask;
 394 {
 395         int omask;
 396
 397         omask = LogMask;
 398         if (pmask != 0)
 399                 LogMask = pmask;
 400         return (omask);
 401 }