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 <stdio_ext.h>
  45 #include <string.h>
  46 #include <time.h>
  47 #include <unistd.h>
  48 #include <stdlib.h>
  49 #include <bits/libc-lock.h>
  50 #include <signal.h>
  51 #include <locale.h>
  52
  53 #if __STDC__
  54 #include <stdarg.h>
  55 #else
  56 #include <varargs.h>
  57 #endif
  58
  59 #include <libio/iolibio.h>
  60 #define ftell(s) INTUSE(_IO_ftell) (s)
  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 #ifndef NO_SIGPIPE
  77 static void sigpipe_handler (int);
  78 #endif
  79
  80 #ifndef send_flags
  81 # define send_flags 0
  82 #endif
  83
  84 struct cleanup_arg
  85 {
  86   void *buf;
  87   struct sigaction *oldaction;
  88 };
  89
  90 static void
  91 cancel_handler (void *ptr)
  92 {
  93 #ifndef NO_SIGPIPE
  94   /* Restore the old signal handler.  */
  95   struct cleanup_arg *clarg = (struct cleanup_arg *) ptr;
  96
  97   if (clarg != NULL && clarg->oldaction != NULL)
  98     __sigaction (SIGPIPE, clarg->oldaction, NULL);
  99 #endif
 100
 101   /* Free the lock.  */
 102   __libc_lock_unlock (syslog_lock);
 103 }
 104
 105
 106 /*
 107  * syslog, vsyslog --
 108  *      print message on log file; output is intended for syslogd(8).
 109  */
 110 void
 111 syslog(int pri, const char *fmt, ...)
 112 {
 113         va_list ap;
 114
 115         va_start(ap, fmt);
 116         __vsyslog_chk(pri, -1, fmt, ap);
 117         va_end(ap);
 118 }
 119 libc_hidden_def (syslog)
 120
 121 void
 122 __syslog_chk(int pri, int flag, const char *fmt, ...)
 123 {
 124         va_list ap;
 125
 126         va_start(ap, fmt);
 127         __vsyslog_chk(pri, flag, fmt, ap);
 128         va_end(ap);
 129 }
 130
 131 void
 132 __vsyslog_chk(int pri, int flag, const char *fmt, va_list ap)
 133 {
 134         struct tm now_tm;
 135         time_t now;
 136         int fd;
 137         FILE *f;
 138         char *buf = 0;
 139         size_t bufsize = 0;
 140         size_t prioff, msgoff;
 141 #ifndef NO_SIGPIPE
 142         struct sigaction action, oldaction;
 143         int sigpipe;
 144 #endif
 145         int saved_errno = errno;
 146         char failbuf[3 * sizeof (pid_t) + sizeof "out of memory []"];
 147
 148 #define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 149         /* Check for invalid bits. */
 150         if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
 151                 syslog(INTERNALLOG,
 152                     "syslog: unknown facility/priority: %x", pri);
 153                 pri &= LOG_PRIMASK|LOG_FACMASK;
 154         }
 155
 156         /* Check priority against setlogmask values. */
 157         if ((LOG_MASK (LOG_PRI (pri)) & LogMask) == 0)
 158                 return;
 159
 160         /* Set default facility if none specified. */
 161         if ((pri & LOG_FACMASK) == 0)
 162                 pri |= LogFacility;
 163
 164         /* Build the message in a memory-buffer stream.  */
 165         f = open_memstream (&buf, &bufsize);
 166         if (f == NULL)
 167           {
 168             /* We cannot get a stream.  There is not much we can do but
 169                emitting an error messages.  */
 170             char numbuf[3 * sizeof (pid_t)];
 171             char *nump;
 172             char *endp = __stpcpy (failbuf, "out of memory [");
 173             pid_t pid = __getpid ();
 174
 175             nump = numbuf + sizeof (numbuf);
 176             /* The PID can never be zero.  */
 177             do
 178               *--nump = '0' + pid % 10;
 179             while ((pid /= 10) != 0);
 180
 181             endp = __mempcpy (endp, nump, (numbuf + sizeof (numbuf)) - nump);
 182             *endp++ = ']';
 183             *endp = '\0';
 184             buf = failbuf;
 185             bufsize = endp - failbuf;
 186             msgoff = 0;
 187           }
 188         else
 189           {
 190             __fsetlocking (f, FSETLOCKING_BYCALLER);
 191             prioff = fprintf (f, "<%d>", pri);
 192             (void) time (&now);
 193             f->_IO_write_ptr += __strftime_l (f->_IO_write_ptr,
 194                                               f->_IO_write_end
 195                                               - f->_IO_write_ptr,
 196                                               "%h %e %T ",
 197                                               __localtime_r (&now, &now_tm),
 198                                               &_nl_C_locobj);
 199             msgoff = ftell (f);
 200             if (LogTag == NULL)
 201               LogTag = __progname;
 202             if (LogTag != NULL)
 203               fputs_unlocked (LogTag, f);
 204             if (LogStat & LOG_PID)
 205               fprintf (f, "[%d]", (int) __getpid ());
 206             if (LogTag != NULL)
 207               {
 208                 putc_unlocked (':', f);
 209                 putc_unlocked (' ', f);
 210               }
 211
 212             /* Restore errno for %m format.  */
 213             __set_errno (saved_errno);
 214
 215             /* We have the header.  Print the user's format into the
 216                buffer.  */
 217             if (flag == -1)
 218               vfprintf (f, fmt, ap);
 219             else
 220               __vfprintf_chk (f, flag, fmt, ap);
 221
 222             /* Close the memory stream; this will finalize the data
 223                into a malloc'd buffer in BUF.  */
 224             fclose (f);
 225           }
 226
 227         /* Output to stderr if requested. */
 228         if (LogStat & LOG_PERROR) {
 229                 struct iovec iov[2];
 230                 register struct iovec *v = iov;
 231
 232                 v->iov_base = buf + msgoff;
 233                 v->iov_len = bufsize - msgoff;
 234                 /* Append a newline if necessary.  */
 235                 if (buf[bufsize - 1] != '\n')
 236                   {
 237                     ++v;
 238                     v->iov_base = (char *) "\n";
 239                     v->iov_len = 1;
 240                   }
 241
 242                 __libc_cleanup_push (free, buf == failbuf ? NULL : buf);
 243
 244                 /* writev is a cancellation point.  */
 245                 (void)__writev(STDERR_FILENO, iov, v - iov + 1);
 246
 247                 __libc_cleanup_pop (0);
 248         }
 249
 250         /* Prepare for multiple users.  We have to take care: open and
 251            write are cancellation points.  */
 252         struct cleanup_arg clarg;
 253         clarg.buf = buf;
 254         clarg.oldaction = NULL;
 255         __libc_cleanup_push (cancel_handler, &clarg);
 256         __libc_lock_lock (syslog_lock);
 257
 258 #ifndef NO_SIGPIPE
 259         /* Prepare for a broken connection.  */
 260         memset (&action, 0, sizeof (action));
 261         action.sa_handler = sigpipe_handler;
 262         sigemptyset (&action.sa_mask);
 263         sigpipe = __sigaction (SIGPIPE, &action, &oldaction);
 264         if (sigpipe == 0)
 265           clarg.oldaction = &oldaction;
 266 #endif
 267
 268         /* Get connected, output the message to the local logger. */
 269         if (!connected)
 270                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 271
 272         /* If we have a SOCK_STREAM connection, also send ASCII NUL as
 273            a record terminator.  */
 274         if (LogType == SOCK_STREAM)
 275           ++bufsize;
 276
 277         if (!connected || __send(LogFile, buf, bufsize, send_flags) < 0)
 278           {
 279             if (connected)
 280               {
 281                 /* Try to reopen the syslog connection.  Maybe it went
 282                    down.  */
 283                 closelog_internal ();
 284                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 285               }
 286
 287             if (!connected || __send(LogFile, buf, bufsize, send_flags) < 0)
 288               {
 289                 closelog_internal ();   /* attempt re-open next time */
 290                 /*
 291                  * Output the message to the console; don't worry
 292                  * about blocking, if console blocks everything will.
 293                  * Make sure the error reported is the one from the
 294                  * syslogd failure.
 295                  */
 296                 if (LogStat & LOG_CONS &&
 297                     (fd = __open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) >= 0)
 298                   {
 299                     dprintf (fd, "%s\r\n", buf + msgoff);
 300                     (void)__close(fd);
 301                   }
 302               }
 303           }
 304
 305 #ifndef NO_SIGPIPE
 306         if (sigpipe == 0)
 307                 __sigaction (SIGPIPE, &oldaction, (struct sigaction *) NULL);
 308 #endif
 309
 310         /* End of critical section.  */
 311         __libc_cleanup_pop (0);
 312         __libc_lock_unlock (syslog_lock);
 313
 314         if (buf != failbuf)
 315                 free (buf);
 316 }
 317 libc_hidden_def (__vsyslog_chk)
 318
 319 void
 320 vsyslog(pri, fmt, ap)
 321         int pri;
 322         register const char *fmt;
 323         va_list ap;
 324 {
 325   __vsyslog_chk (pri, -1, fmt, ap);
 326 }
 327 libc_hidden_def (vsyslog)
 328
 329 static struct sockaddr SyslogAddr;      /* AF_UNIX address of local logger */
 330
 331
 332 static void
 333 internal_function
 334 openlog_internal(const char *ident, int logstat, int logfac)
 335 {
 336         if (ident != NULL)
 337                 LogTag = ident;
 338         LogStat = logstat;
 339         if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
 340                 LogFacility = logfac;
 341
 342         int retry = 0;
 343         while (retry < 2) {
 344                 if (LogFile == -1) {
 345                         SyslogAddr.sa_family = AF_UNIX;
 346                         (void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
 347                                       sizeof(SyslogAddr.sa_data));
 348                         if (LogStat & LOG_NDELAY) {
 349                                 if ((LogFile = __socket(AF_UNIX, LogType, 0))
 350                                     == -1)
 351                                         return;
 352                                 (void)__fcntl(LogFile, F_SETFD, 1);
 353                         }
 354                 }
 355                 if (LogFile != -1 && !connected)
 356                 {
 357                         int old_errno = errno;
 358                         if (__connect(LogFile, &SyslogAddr, sizeof(SyslogAddr))
 359                             == -1)
 360                         {
 361                                 int saved_errno = errno;
 362                                 int fd = LogFile;
 363                                 LogFile = -1;
 364                                 (void)__close(fd);
 365                                 __set_errno (old_errno);
 366                                 if (saved_errno == EPROTOTYPE)
 367                                 {
 368                                         /* retry with the other type: */
 369                                         LogType = (LogType == SOCK_DGRAM
 370                                                    ? SOCK_STREAM : SOCK_DGRAM);
 371                                         ++retry;
 372                                         continue;
 373                                 }
 374                         } else
 375                                 connected = 1;
 376                 }
 377                 break;
 378         }
 379 }
 380
 381 void
 382 openlog (const char *ident, int logstat, int logfac)
 383 {
 384   /* Protect against multiple users and cancellation.  */
 385   __libc_cleanup_push (cancel_handler, NULL);
 386   __libc_lock_lock (syslog_lock);
 387
 388   openlog_internal (ident, logstat, logfac);
 389
 390   __libc_cleanup_pop (1);
 391 }
 392
 393 #ifndef NO_SIGPIPE
 394 static void
 395 sigpipe_handler (int signo)
 396 {
 397   closelog_internal ();
 398 }
 399 #endif
 400
 401 static void
 402 closelog_internal()
 403 {
 404   if (!connected)
 405     return;
 406
 407   __close (LogFile);
 408   LogFile = -1;
 409   connected = 0;
 410 }
 411
 412 void
 413 closelog ()
 414 {
 415   /* Protect against multiple users and cancellation.  */
 416   __libc_cleanup_push (cancel_handler, NULL);
 417   __libc_lock_lock (syslog_lock);
 418
 419   closelog_internal ();
 420   LogTag = NULL;
 421   LogType = SOCK_DGRAM; /* this is the default */
 422
 423   /* Free the lock.  */
 424   __libc_cleanup_pop (1);
 425 }
 426
 427 /* setlogmask -- set the log mask level */
 428 int
 429 setlogmask(pmask)
 430         int pmask;
 431 {
 432         int omask;
 433
 434         omask = LogMask;
 435         if (pmask != 0)
 436                 LogMask = pmask;
 437         return (omask);
 438 }