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