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