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 <sys/un.h>
  39 #include <netdb.h>
  40
  41 #include <errno.h>
  42 #include <fcntl.h>
  43 #include <paths.h>
  44 #include <stdio.h>
  45 #include <stdio_ext.h>
  46 #include <string.h>
  47 #include <time.h>
  48 #include <unistd.h>
  49 #include <stdlib.h>
  50 #include <bits/libc-lock.h>
  51 #include <signal.h>
  52 #include <locale.h>
  53
  54 #if __STDC__
  55 #include <stdarg.h>
  56 #else
  57 #include <varargs.h>
  58 #endif
  59
  60 #include <libio/iolibio.h>
  61 #define ftell(s) INTUSE(_IO_ftell) (s)
  62
  63 static int      LogType = SOCK_DGRAM;   /* type of socket connection */
  64 static int      LogFile = -1;           /* fd for log */
  65 static int      connected;              /* have done connect */
  66 static int      LogStat;                /* status bits, set by openlog() */
  67 static const char *LogTag;              /* string to tag the entry with */
  68 static int      LogFacility = LOG_USER; /* default facility code */
  69 static int      LogMask = 0xff;         /* mask of priorities to be logged */
  70 extern char     *__progname;            /* Program name, from crt0. */
  71
  72 /* Define the lock.  */
  73 __libc_lock_define_initialized (static, syslog_lock)
  74
  75 static void openlog_internal(const char *, int, int) internal_function;
  76 static void closelog_internal(void);
  77 #ifndef NO_SIGPIPE
  78 static void sigpipe_handler (int);
  79 #endif
  80
  81 #ifndef send_flags
  82 # define send_flags 0
  83 #endif
  84
  85 struct cleanup_arg
  86 {
  87   void *buf;
  88   struct sigaction *oldaction;
  89 };
  90
  91 static void
  92 cancel_handler (void *ptr)
  93 {
  94 #ifndef NO_SIGPIPE
  95   /* Restore the old signal handler.  */
  96   struct cleanup_arg *clarg = (struct cleanup_arg *) ptr;
  97
  98   if (clarg != NULL && clarg->oldaction != NULL)
  99     __sigaction (SIGPIPE, clarg->oldaction, NULL);
 100 #endif
 101
 102   /* Free the lock.  */
 103   __libc_lock_unlock (syslog_lock);
 104 }
 105
 106
 107 /*
 108  * syslog, vsyslog --
 109  *      print message on log file; output is intended for syslogd(8).
 110  */
 111 void
 112 syslog(int pri, const char *fmt, ...)
 113 {
 114         va_list ap;
 115
 116         va_start(ap, fmt);
 117         __vsyslog_chk(pri, -1, fmt, ap);
 118         va_end(ap);
 119 }
 120 libc_hidden_def (syslog)
 121
 122 void
 123 __syslog_chk(int pri, int flag, const char *fmt, ...)
 124 {
 125         va_list ap;
 126
 127         va_start(ap, fmt);
 128         __vsyslog_chk(pri, flag, fmt, ap);
 129         va_end(ap);
 130 }
 131
 132 void
 133 __vsyslog_chk(int pri, int flag, const char *fmt, va_list ap)
 134 {
 135         struct tm now_tm;
 136         time_t now;
 137         int fd;
 138         FILE *f;
 139         char *buf = 0;
 140         size_t bufsize = 0;
 141         size_t prioff, msgoff;
 142 #ifndef NO_SIGPIPE
 143         struct sigaction action, oldaction;
 144         int sigpipe;
 145 #endif
 146         int saved_errno = errno;
 147         char failbuf[3 * sizeof (pid_t) + sizeof "out of memory []"];
 148
 149 #define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 150         /* Check for invalid bits. */
 151         if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
 152                 syslog(INTERNALLOG,
 153                     "syslog: unknown facility/priority: %x", pri);
 154                 pri &= LOG_PRIMASK|LOG_FACMASK;
 155         }
 156
 157         /* Check priority against setlogmask values. */
 158         if ((LOG_MASK (LOG_PRI (pri)) & LogMask) == 0)
 159                 return;
 160
 161         /* Set default facility if none specified. */
 162         if ((pri & LOG_FACMASK) == 0)
 163                 pri |= LogFacility;
 164
 165         /* Build the message in a memory-buffer stream.  */
 166         f = open_memstream (&buf, &bufsize);
 167         if (f == NULL)
 168           {
 169             /* We cannot get a stream.  There is not much we can do but
 170                emitting an error messages.  */
 171             char numbuf[3 * sizeof (pid_t)];
 172             char *nump;
 173             char *endp = __stpcpy (failbuf, "out of memory [");
 174             pid_t pid = __getpid ();
 175
 176             nump = numbuf + sizeof (numbuf);
 177             /* The PID can never be zero.  */
 178             do
 179               *--nump = '0' + pid % 10;
 180             while ((pid /= 10) != 0);
 181
 182             endp = __mempcpy (endp, nump, (numbuf + sizeof (numbuf)) - nump);
 183             *endp++ = ']';
 184             *endp = '\0';
 185             buf = failbuf;
 186             bufsize = endp - failbuf;
 187             msgoff = 0;
 188           }
 189         else
 190           {
 191             __fsetlocking (f, FSETLOCKING_BYCALLER);
 192             prioff = fprintf (f, "<%d>", pri);
 193             (void) time (&now);
 194             f->_IO_write_ptr += __strftime_l (f->_IO_write_ptr,
 195                                               f->_IO_write_end
 196                                               - f->_IO_write_ptr,
 197                                               "%h %e %T ",
 198                                               __localtime_r (&now, &now_tm),
 199                                               _nl_C_locobj_ptr);
 200             msgoff = ftell (f);
 201             if (LogTag == NULL)
 202               LogTag = __progname;
 203             if (LogTag != NULL)
 204               fputs_unlocked (LogTag, f);
 205             if (LogStat & LOG_PID)
 206               fprintf (f, "[%d]", (int) __getpid ());
 207             if (LogTag != NULL)
 208               {
 209                 putc_unlocked (':', f);
 210                 putc_unlocked (' ', f);
 211               }
 212
 213             /* Restore errno for %m format.  */
 214             __set_errno (saved_errno);
 215
 216             /* We have the header.  Print the user's format into the
 217                buffer.  */
 218             if (flag == -1)
 219               vfprintf (f, fmt, ap);
 220             else
 221               __vfprintf_chk (f, flag, fmt, ap);
 222
 223             /* Close the memory stream; this will finalize the data
 224                into a malloc'd buffer in BUF.  */
 225             fclose (f);
 226           }
 227
 228         /* Output to stderr if requested. */
 229         if (LogStat & LOG_PERROR) {
 230                 struct iovec iov[2];
 231                 register struct iovec *v = iov;
 232
 233                 v->iov_base = buf + msgoff;
 234                 v->iov_len = bufsize - msgoff;
 235                 /* Append a newline if necessary.  */
 236                 if (buf[bufsize - 1] != '\n')
 237                   {
 238                     ++v;
 239                     v->iov_base = (char *) "\n";
 240                     v->iov_len = 1;
 241                   }
 242
 243                 __libc_cleanup_push (free, buf == failbuf ? NULL : buf);
 244
 245                 /* writev is a cancellation point.  */
 246                 (void)__writev(STDERR_FILENO, iov, v - iov + 1);
 247
 248                 __libc_cleanup_pop (0);
 249         }
 250
 251         /* Prepare for multiple users.  We have to take care: open and
 252            write are cancellation points.  */
 253         struct cleanup_arg clarg;
 254         clarg.buf = buf;
 255         clarg.oldaction = NULL;
 256         __libc_cleanup_push (cancel_handler, &clarg);
 257         __libc_lock_lock (syslog_lock);
 258
 259 #ifndef NO_SIGPIPE
 260         /* Prepare for a broken connection.  */
 261         memset (&action, 0, sizeof (action));
 262         action.sa_handler = sigpipe_handler;
 263         sigemptyset (&action.sa_mask);
 264         sigpipe = __sigaction (SIGPIPE, &action, &oldaction);
 265         if (sigpipe == 0)
 266           clarg.oldaction = &oldaction;
 267 #endif
 268
 269         /* Get connected, output the message to the local logger. */
 270         if (!connected)
 271                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 272
 273         /* If we have a SOCK_STREAM connection, also send ASCII NUL as
 274            a record terminator.  */
 275         if (LogType == SOCK_STREAM)
 276           ++bufsize;
 277
 278         if (!connected || __send(LogFile, buf, bufsize, send_flags) < 0)
 279           {
 280             if (connected)
 281               {
 282                 /* Try to reopen the syslog connection.  Maybe it went
 283                    down.  */
 284                 closelog_internal ();
 285                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 286               }
 287
 288             if (!connected || __send(LogFile, buf, bufsize, send_flags) < 0)
 289               {
 290                 closelog_internal ();   /* attempt re-open next time */
 291                 /*
 292                  * Output the message to the console; don't worry
 293                  * about blocking, if console blocks everything will.
 294                  * Make sure the error reported is the one from the
 295                  * syslogd failure.
 296                  */
 297                 if (LogStat & LOG_CONS &&
 298                     (fd = __open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) >= 0)
 299                   {
 300                     dprintf (fd, "%s\r\n", buf + msgoff);
 301                     (void)__close(fd);
 302                   }
 303               }
 304           }
 305
 306 #ifndef NO_SIGPIPE
 307         if (sigpipe == 0)
 308                 __sigaction (SIGPIPE, &oldaction, (struct sigaction *) NULL);
 309 #endif
 310
 311         /* End of critical section.  */
 312         __libc_cleanup_pop (0);
 313         __libc_lock_unlock (syslog_lock);
 314
 315         if (buf != failbuf)
 316                 free (buf);
 317 }
 318 libc_hidden_def (__vsyslog_chk)
 319
 320 void
 321 vsyslog(pri, fmt, ap)
 322         int pri;
 323         register const char *fmt;
 324         va_list ap;
 325 {
 326   __vsyslog_chk (pri, -1, fmt, ap);
 327 }
 328 libc_hidden_def (vsyslog)
 329
 330 static struct sockaddr_un SyslogAddr;   /* AF_UNIX address of local logger */
 331
 332
 333 static void
 334 internal_function
 335 openlog_internal(const char *ident, int logstat, int logfac)
 336 {
 337         if (ident != NULL)
 338                 LogTag = ident;
 339         LogStat = logstat;
 340         if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
 341                 LogFacility = logfac;
 342
 343         int retry = 0;
 344         while (retry < 2) {
 345                 if (LogFile == -1) {
 346                         SyslogAddr.sun_family = AF_UNIX;
 347                         (void)strncpy(SyslogAddr.sun_path, _PATH_LOG,
 348                                       sizeof(SyslogAddr.sun_path));
 349                         if (LogStat & LOG_NDELAY) {
 350                                 if ((LogFile = __socket(AF_UNIX, LogType, 0))
 351                                     == -1)
 352                                         return;
 353                                 (void)__fcntl(LogFile, F_SETFD, 1);
 354                         }
 355                 }
 356                 if (LogFile != -1 && !connected)
 357                 {
 358                         int old_errno = errno;
 359                         if (__connect(LogFile, &SyslogAddr, sizeof(SyslogAddr))
 360                             == -1)
 361                         {
 362                                 int saved_errno = errno;
 363                                 int fd = LogFile;
 364                                 LogFile = -1;
 365                                 (void)__close(fd);
 366                                 __set_errno (old_errno);
 367                                 if (saved_errno == EPROTOTYPE)
 368                                 {
 369                                         /* retry with the other type: */
 370                                         LogType = (LogType == SOCK_DGRAM
 371                                                    ? SOCK_STREAM : SOCK_DGRAM);
 372                                         ++retry;
 373                                         continue;
 374                                 }
 375                         } else
 376                                 connected = 1;
 377                 }
 378                 break;
 379         }
 380 }
 381
 382 void
 383 openlog (const char *ident, int logstat, int logfac)
 384 {
 385   /* Protect against multiple users and cancellation.  */
 386   __libc_cleanup_push (cancel_handler, NULL);
 387   __libc_lock_lock (syslog_lock);
 388
 389   openlog_internal (ident, logstat, logfac);
 390
 391   __libc_cleanup_pop (1);
 392 }
 393
 394 #ifndef NO_SIGPIPE
 395 static void
 396 sigpipe_handler (int signo)
 397 {
 398   closelog_internal ();
 399 }
 400 #endif
 401
 402 static void
 403 closelog_internal()
 404 {
 405   if (!connected)
 406     return;
 407
 408   __close (LogFile);
 409   LogFile = -1;
 410   connected = 0;
 411 }
 412
 413 void
 414 closelog ()
 415 {
 416   /* Protect against multiple users and cancellation.  */
 417   __libc_cleanup_push (cancel_handler, NULL);
 418   __libc_lock_lock (syslog_lock);
 419
 420   closelog_internal ();
 421   LogTag = NULL;
 422   LogType = SOCK_DGRAM; /* this is the default */
 423
 424   /* Free the lock.  */
 425   __libc_cleanup_pop (1);
 426 }
 427
 428 /* setlogmask -- set the log mask level */
 429 int
 430 setlogmask(pmask)
 431         int pmask;
 432 {
 433         int omask;
 434
 435         omask = LogMask;
 436         if (pmask != 0)
 437                 LogMask = pmask;
 438         return (omask);
 439 }