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) INTUSE(_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 libc_hidden_def (syslog)
 106
 107 void
 108 vsyslog(pri, fmt, ap)
 109         int pri;
 110         register const char *fmt;
 111         va_list ap;
 112 {
 113         struct tm now_tm;
 114         time_t now;
 115         int fd;
 116         FILE *f;
 117         char *buf = 0;
 118         size_t bufsize = 0;
 119         size_t prioff, msgoff;
 120         struct sigaction action, oldaction;
 121         struct sigaction *oldaction_ptr = NULL;
 122         int sigpipe;
 123         int saved_errno = errno;
 124         char failbuf[3 * sizeof (pid_t) + sizeof "out of memory []"];
 125
 126 #define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 127         /* Check for invalid bits. */
 128         if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
 129                 syslog(INTERNALLOG,
 130                     "syslog: unknown facility/priority: %x", pri);
 131                 pri &= LOG_PRIMASK|LOG_FACMASK;
 132         }
 133
 134         /* Check priority against setlogmask values. */
 135         if ((LOG_MASK (LOG_PRI (pri)) & LogMask) == 0)
 136                 return;
 137
 138         /* Set default facility if none specified. */
 139         if ((pri & LOG_FACMASK) == 0)
 140                 pri |= LogFacility;
 141
 142         /* Build the message in a memory-buffer stream.  */
 143         f = open_memstream (&buf, &bufsize);
 144         if (f == NULL)
 145           {
 146             /* We cannot get a stream.  There is not much we can do but
 147                emitting an error messages.  */
 148             char numbuf[3 * sizeof (pid_t)];
 149             char *nump;
 150             char *endp = __stpcpy (failbuf, "out of memory [");
 151             pid_t pid = __getpid ();
 152
 153             nump = numbuf + sizeof (numbuf);
 154             /* The PID can never be zero.  */
 155             do
 156               *--nump = '0' + pid % 10;
 157             while ((pid /= 10) != 0);
 158
 159             endp = __mempcpy (endp, nump, (nump + sizeof (numbuf)) - nump);
 160             *endp++ = ']';
 161             *endp = '\0';
 162             buf = failbuf;
 163             bufsize = endp - failbuf;
 164             msgoff = 0;
 165           }
 166         else
 167           {
 168             prioff = fprintf (f, "<%d>", pri);
 169             (void) time (&now);
 170 #ifdef USE_IN_LIBIO
 171             f->_IO_write_ptr += strftime (f->_IO_write_ptr,
 172                                           f->_IO_write_end - f->_IO_write_ptr,
 173                                           "%h %e %T ",
 174                                           __localtime_r (&now, &now_tm));
 175 #else
 176             f->__bufp += strftime (f->__bufp, f->__put_limit - f->__bufp,
 177                                    "%h %e %T ", __localtime_r (&now, &now_tm));
 178 #endif
 179             msgoff = ftell (f);
 180             if (LogTag == NULL)
 181               LogTag = __progname;
 182             if (LogTag != NULL)
 183               fputs_unlocked (LogTag, f);
 184             if (LogStat & LOG_PID)
 185               fprintf (f, "[%d]", __getpid ());
 186             if (LogTag != NULL)
 187               putc_unlocked (':', f), putc_unlocked (' ', f);
 188
 189             /* Restore errno for %m format.  */
 190             __set_errno (saved_errno);
 191
 192             /* We have the header.  Print the user's format into the
 193                buffer.  */
 194             vfprintf (f, fmt, ap);
 195
 196             /* Close the memory stream; this will finalize the data
 197                into a malloc'd buffer in BUF.  */
 198             fclose (f);
 199           }
 200
 201         /* Output to stderr if requested. */
 202         if (LogStat & LOG_PERROR) {
 203                 struct iovec iov[2];
 204                 register struct iovec *v = iov;
 205
 206                 v->iov_base = buf + msgoff;
 207                 v->iov_len = bufsize - msgoff;
 208                 /* Append a newline if necessary.  */
 209                 if (buf[bufsize - 1] != '\n')
 210                   {
 211                     ++v;
 212                     v->iov_base = (char *) "\n";
 213                     v->iov_len = 1;
 214                   }
 215                 (void)__writev(STDERR_FILENO, iov, v - iov + 1);
 216         }
 217
 218 #ifdef _LIBC_REENTRANT
 219         /* Prepare for multiple users.  We have to take care: open and
 220            write are cancellation points.  */
 221         __libc_cleanup_region_start (1, (void (*) (void *)) cancel_handler,
 222                                      &oldaction_ptr);
 223         __libc_lock_lock (syslog_lock);
 224 #endif
 225
 226         /* Prepare for a broken connection.  */
 227         memset (&action, 0, sizeof (action));
 228         action.sa_handler = sigpipe_handler;
 229         sigemptyset (&action.sa_mask);
 230         sigpipe = __sigaction (SIGPIPE, &action, &oldaction);
 231         if (sigpipe == 0)
 232           oldaction_ptr = &oldaction;
 233
 234         /* Get connected, output the message to the local logger. */
 235         if (!connected)
 236                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 237
 238         /* If we have a SOCK_STREAM connection, also send ASCII NUL as
 239            a record terminator.  */
 240         if (LogType == SOCK_STREAM)
 241           ++bufsize;
 242
 243         if (!connected || __send(LogFile, buf, bufsize, 0) < 0)
 244           {
 245             if (connected)
 246               {
 247                 /* Try to reopen the syslog connection.  Maybe it went
 248                    down.  */
 249                 closelog_internal ();
 250                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 251               }
 252
 253             if (!connected || __send(LogFile, buf, bufsize, 0) < 0)
 254               {
 255                 closelog_internal ();   /* attempt re-open next time */
 256                 /*
 257                  * Output the message to the console; don't worry
 258                  * about blocking, if console blocks everything will.
 259                  * Make sure the error reported is the one from the
 260                  * syslogd failure.
 261                  */
 262                 if (LogStat & LOG_CONS &&
 263                     (fd = __open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) >= 0)
 264                   {
 265                     dprintf (fd, "%s\r\n", buf + msgoff);
 266                     (void)__close(fd);
 267                   }
 268               }
 269           }
 270
 271         if (sigpipe == 0)
 272                 __sigaction (SIGPIPE, &oldaction, (struct sigaction *) NULL);
 273
 274 #ifdef _LIBC_REENTRANT
 275         /* End of critical section.  */
 276         __libc_cleanup_region_end (0);
 277         __libc_lock_unlock (syslog_lock);
 278 #endif
 279
 280         free (buf);
 281 }
 282 libc_hidden_def (vsyslog)
 283
 284 static struct sockaddr SyslogAddr;      /* AF_UNIX address of local logger */
 285
 286 static void
 287 internal_function
 288 openlog_internal(const char *ident, int logstat, int logfac)
 289 {
 290         if (ident != NULL)
 291                 LogTag = ident;
 292         LogStat = logstat;
 293         if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
 294                 LogFacility = logfac;
 295
 296         while (1) {
 297                 if (LogFile == -1) {
 298                         SyslogAddr.sa_family = AF_UNIX;
 299                         (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
 300                                       sizeof(SyslogAddr.sa_data));
 301                         if (LogStat & LOG_NDELAY) {
 302                                 if ((LogFile = __socket(AF_UNIX, LogType, 0))
 303                                     == -1)
 304                                         return;
 305                                 (void)__fcntl(LogFile, F_SETFD, 1);
 306                         }
 307                 }
 308                 if (LogFile != -1 && !connected)
 309                 {
 310                         int old_errno = errno;
 311                         if (__connect(LogFile, &SyslogAddr, sizeof(SyslogAddr))
 312                             == -1)
 313                         {
 314                                 int saved_errno = errno;
 315                                 (void)__close(LogFile);
 316                                 LogFile = -1;
 317                                 if (LogType == SOCK_DGRAM
 318                                     && saved_errno == EPROTOTYPE)
 319                                 {
 320                                         /* retry with next SOCK_STREAM: */
 321                                         LogType = SOCK_STREAM;
 322                                         __set_errno (old_errno);
 323                                         continue;
 324                                 }
 325                         } else
 326                                 connected = 1;
 327                 }
 328                 break;
 329         }
 330 }
 331
 332
 333 static void
 334 log_cleanup (void *arg)
 335 {
 336   __libc_lock_unlock (syslog_lock);
 337 }
 338
 339 void
 340 openlog (const char *ident, int logstat, int logfac)
 341 {
 342 #ifdef _LIBC_REENTRANT
 343   /* Protect against multiple users.  */
 344   __libc_cleanup_region_start (1, log_cleanup, NULL);
 345   __libc_lock_lock (syslog_lock);
 346 #endif
 347
 348   openlog_internal (ident, logstat, logfac);
 349
 350 #ifdef _LIBC_REENTRANT
 351   /* Free the lock.  */
 352   __libc_cleanup_region_end (1);
 353 #endif
 354 }
 355
 356 static void
 357 sigpipe_handler (int signo)
 358 {
 359   closelog_internal ();
 360 }
 361
 362 static void
 363 closelog_internal()
 364 {
 365   if (!connected)
 366     return;
 367
 368   __close (LogFile);
 369   LogFile = -1;
 370   connected = 0;
 371 }
 372
 373 void
 374 closelog ()
 375 {
 376 #ifdef _LIBC_REENTRANT
 377   /* Protect against multiple users.  */
 378   __libc_cleanup_region_start (1, log_cleanup, NULL);
 379   __libc_lock_lock (syslog_lock);
 380 #endif
 381
 382   closelog_internal ();
 383   LogTag = NULL;
 384   LogType = SOCK_DGRAM; /* this is the default */
 385
 386 #ifdef _LIBC_REENTRANT
 387   /* Free the lock.  */
 388   __libc_cleanup_region_end (1);
 389 #endif
 390 }
 391
 392 #ifdef _LIBC_REENTRANT
 393 static void
 394 cancel_handler (void *ptr)
 395 {
 396   /* Restore the old signal handler.  */
 397   struct sigaction *oldaction = *((struct sigaction **) ptr);
 398
 399   if (oldaction != (struct sigaction *) NULL)
 400     __sigaction (SIGPIPE, oldaction, (struct sigaction *) NULL);
 401
 402   /* Free the lock.  */
 403   __libc_lock_unlock (syslog_lock);
 404 }
 405 #endif
 406
 407 /* setlogmask -- set the log mask level */
 408 int
 409 setlogmask(pmask)
 410         int pmask;
 411 {
 412         int omask;
 413
 414         omask = LogMask;
 415         if (pmask != 0)
 416                 LogMask = pmask;
 417         return (omask);
 418 }