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