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 #include <math_ldbl_opt.h>
  62
  63 #define ftell(s) INTUSE(_IO_ftell) (s)
  64
  65 static int      LogType = SOCK_DGRAM;   /* type of socket connection */
  66 static int      LogFile = -1;           /* fd for log */
  67 static int      connected;              /* have done connect */
  68 static int      LogStat;                /* status bits, set by openlog() */
  69 static const char *LogTag;              /* string to tag the entry with */
  70 static int      LogFacility = LOG_USER; /* default facility code */
  71 static int      LogMask = 0xff;         /* mask of priorities to be logged */
  72 extern char     *__progname;            /* Program name, from crt0. */
  73
  74 /* Define the lock.  */
  75 __libc_lock_define_initialized (static, syslog_lock)
  76
  77 static void openlog_internal(const char *, int, int) internal_function;
  78 static void closelog_internal(void);
  79 #ifndef NO_SIGPIPE
  80 static void sigpipe_handler (int);
  81 #endif
  82
  83 #ifndef send_flags
  84 # define send_flags 0
  85 #endif
  86
  87 struct cleanup_arg
  88 {
  89   void *buf;
  90   struct sigaction *oldaction;
  91 };
  92
  93 static void
  94 cancel_handler (void *ptr)
  95 {
  96 #ifndef NO_SIGPIPE
  97   /* Restore the old signal handler.  */
  98   struct cleanup_arg *clarg = (struct cleanup_arg *) ptr;
  99
 100   if (clarg != NULL && clarg->oldaction != NULL)
 101     __sigaction (SIGPIPE, clarg->oldaction, NULL);
 102 #endif
 103
 104   /* Free the lock.  */
 105   __libc_lock_unlock (syslog_lock);
 106 }
 107
 108
 109 /*
 110  * syslog, vsyslog --
 111  *      print message on log file; output is intended for syslogd(8).
 112  */
 113 void
 114 __syslog(int pri, const char *fmt, ...)
 115 {
 116         va_list ap;
 117
 118         va_start(ap, fmt);
 119         __vsyslog_chk(pri, -1, fmt, ap);
 120         va_end(ap);
 121 }
 122 ldbl_hidden_def (__syslog, syslog)
 123 ldbl_strong_alias (__syslog, syslog)
 124
 125 void
 126 __syslog_chk(int pri, int flag, const char *fmt, ...)
 127 {
 128         va_list ap;
 129
 130         va_start(ap, fmt);
 131         __vsyslog_chk(pri, flag, fmt, ap);
 132         va_end(ap);
 133 }
 134
 135 void
 136 __vsyslog_chk(int pri, int flag, const char *fmt, va_list ap)
 137 {
 138         struct tm now_tm;
 139         time_t now;
 140         int fd;
 141         FILE *f;
 142         char *buf = 0;
 143         size_t bufsize = 0;
 144         size_t prioff, msgoff;
 145 #ifndef NO_SIGPIPE
 146         struct sigaction action, oldaction;
 147         int sigpipe;
 148 #endif
 149         int saved_errno = errno;
 150         char failbuf[3 * sizeof (pid_t) + sizeof "out of memory []"];
 151
 152 #define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 153         /* Check for invalid bits. */
 154         if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
 155                 syslog(INTERNALLOG,
 156                     "syslog: unknown facility/priority: %x", pri);
 157                 pri &= LOG_PRIMASK|LOG_FACMASK;
 158         }
 159
 160         /* Check priority against setlogmask values. */
 161         if ((LOG_MASK (LOG_PRI (pri)) & LogMask) == 0)
 162                 return;
 163
 164         /* Set default facility if none specified. */
 165         if ((pri & LOG_FACMASK) == 0)
 166                 pri |= LogFacility;
 167
 168         /* Build the message in a memory-buffer stream.  */
 169         f = open_memstream (&buf, &bufsize);
 170         if (f == NULL)
 171           {
 172             /* We cannot get a stream.  There is not much we can do but
 173                emitting an error messages.  */
 174             char numbuf[3 * sizeof (pid_t)];
 175             char *nump;
 176             char *endp = __stpcpy (failbuf, "out of memory [");
 177             pid_t pid = __getpid ();
 178
 179             nump = numbuf + sizeof (numbuf);
 180             /* The PID can never be zero.  */
 181             do
 182               *--nump = '0' + pid % 10;
 183             while ((pid /= 10) != 0);
 184
 185             endp = __mempcpy (endp, nump, (numbuf + sizeof (numbuf)) - nump);
 186             *endp++ = ']';
 187             *endp = '\0';
 188             buf = failbuf;
 189             bufsize = endp - failbuf;
 190             msgoff = 0;
 191           }
 192         else
 193           {
 194             __fsetlocking (f, FSETLOCKING_BYCALLER);
 195             prioff = fprintf (f, "<%d>", pri);
 196             (void) time (&now);
 197             f->_IO_write_ptr += __strftime_l (f->_IO_write_ptr,
 198                                               f->_IO_write_end
 199                                               - f->_IO_write_ptr,
 200                                               "%h %e %T ",
 201                                               __localtime_r (&now, &now_tm),
 202                                               _nl_C_locobj_ptr);
 203             msgoff = ftell (f);
 204             if (LogTag == NULL)
 205               LogTag = __progname;
 206             if (LogTag != NULL)
 207               fputs_unlocked (LogTag, f);
 208             if (LogStat & LOG_PID)
 209               fprintf (f, "[%d]", (int) __getpid ());
 210             if (LogTag != NULL)
 211               {
 212                 putc_unlocked (':', f);
 213                 putc_unlocked (' ', f);
 214               }
 215
 216             /* Restore errno for %m format.  */
 217             __set_errno (saved_errno);
 218
 219             /* We have the header.  Print the user's format into the
 220                buffer.  */
 221             if (flag == -1)
 222               vfprintf (f, fmt, ap);
 223             else
 224               __vfprintf_chk (f, flag, fmt, ap);
 225
 226             /* Close the memory stream; this will finalize the data
 227                into a malloc'd buffer in BUF.  */
 228             fclose (f);
 229           }
 230
 231         /* Output to stderr if requested. */
 232         if (LogStat & LOG_PERROR) {
 233                 struct iovec iov[2];
 234                 register struct iovec *v = iov;
 235
 236                 v->iov_base = buf + msgoff;
 237                 v->iov_len = bufsize - msgoff;
 238                 /* Append a newline if necessary.  */
 239                 if (buf[bufsize - 1] != '\n')
 240                   {
 241                     ++v;
 242                     v->iov_base = (char *) "\n";
 243                     v->iov_len = 1;
 244                   }
 245
 246                 __libc_cleanup_push (free, buf == failbuf ? NULL : buf);
 247
 248                 /* writev is a cancellation point.  */
 249                 (void)__writev(STDERR_FILENO, iov, v - iov + 1);
 250
 251                 __libc_cleanup_pop (0);
 252         }
 253
 254         /* Prepare for multiple users.  We have to take care: open and
 255            write are cancellation points.  */
 256         struct cleanup_arg clarg;
 257         clarg.buf = buf;
 258         clarg.oldaction = NULL;
 259         __libc_cleanup_push (cancel_handler, &clarg);
 260         __libc_lock_lock (syslog_lock);
 261
 262 #ifndef NO_SIGPIPE
 263         /* Prepare for a broken connection.  */
 264         memset (&action, 0, sizeof (action));
 265         action.sa_handler = sigpipe_handler;
 266         sigemptyset (&action.sa_mask);
 267         sigpipe = __sigaction (SIGPIPE, &action, &oldaction);
 268         if (sigpipe == 0)
 269           clarg.oldaction = &oldaction;
 270 #endif
 271
 272         /* Get connected, output the message to the local logger. */
 273         if (!connected)
 274                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 275
 276         /* If we have a SOCK_STREAM connection, also send ASCII NUL as
 277            a record terminator.  */
 278         if (LogType == SOCK_STREAM)
 279           ++bufsize;
 280
 281         if (!connected || __send(LogFile, buf, bufsize, send_flags) < 0)
 282           {
 283             if (connected)
 284               {
 285                 /* Try to reopen the syslog connection.  Maybe it went
 286                    down.  */
 287                 closelog_internal ();
 288                 openlog_internal(LogTag, LogStat | LOG_NDELAY, 0);
 289               }
 290
 291             if (!connected || __send(LogFile, buf, bufsize, send_flags) < 0)
 292               {
 293                 closelog_internal ();   /* attempt re-open next time */
 294                 /*
 295                  * Output the message to the console; don't worry
 296                  * about blocking, if console blocks everything will.
 297                  * Make sure the error reported is the one from the
 298                  * syslogd failure.
 299                  */
 300                 if (LogStat & LOG_CONS &&
 301                     (fd = __open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY, 0)) >= 0)
 302                   {
 303                     dprintf (fd, "%s\r\n", buf + msgoff);
 304                     (void)__close(fd);
 305                   }
 306               }
 307           }
 308
 309 #ifndef NO_SIGPIPE
 310         if (sigpipe == 0)
 311                 __sigaction (SIGPIPE, &oldaction, (struct sigaction *) NULL);
 312 #endif
 313
 314         /* End of critical section.  */
 315         __libc_cleanup_pop (0);
 316         __libc_lock_unlock (syslog_lock);
 317
 318         if (buf != failbuf)
 319                 free (buf);
 320 }
 321 libc_hidden_def (__vsyslog_chk)
 322
 323 void
 324 __vsyslog(int pri, const char *fmt, va_list ap)
 325 {
 326   __vsyslog_chk (pri, -1, fmt, ap);
 327 }
 328 ldbl_hidden_def (__vsyslog, vsyslog)
 329 ldbl_strong_alias (__vsyslog, vsyslog)
 330
 331 static struct sockaddr_un SyslogAddr;   /* AF_UNIX address of local logger */
 332
 333
 334 static void
 335 internal_function
 336 openlog_internal(const char *ident, int logstat, int logfac)
 337 {
 338         if (ident != NULL)
 339                 LogTag = ident;
 340         LogStat = logstat;
 341         if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
 342                 LogFacility = logfac;
 343
 344         int retry = 0;
 345         while (retry < 2) {
 346                 if (LogFile == -1) {
 347                         SyslogAddr.sun_family = AF_UNIX;
 348                         (void)strncpy(SyslogAddr.sun_path, _PATH_LOG,
 349                                       sizeof(SyslogAddr.sun_path));
 350                         if (LogStat & LOG_NDELAY) {
 351                                 if ((LogFile = __socket(AF_UNIX, LogType, 0))
 352                                     == -1)
 353                                         return;
 354                                 (void)__fcntl(LogFile, F_SETFD, 1);
 355                         }
 356                 }
 357                 if (LogFile != -1 && !connected)
 358                 {
 359                         int old_errno = errno;
 360                         if (__connect(LogFile, &SyslogAddr, sizeof(SyslogAddr))
 361                             == -1)
 362                         {
 363                                 int saved_errno = errno;
 364                                 int fd = LogFile;
 365                                 LogFile = -1;
 366                                 (void)__close(fd);
 367                                 __set_errno (old_errno);
 368                                 if (saved_errno == EPROTOTYPE)
 369                                 {
 370                                         /* retry with the other type: */
 371                                         LogType = (LogType == SOCK_DGRAM
 372                                                    ? SOCK_STREAM : SOCK_DGRAM);
 373                                         ++retry;
 374                                         continue;
 375                                 }
 376                         } else
 377                                 connected = 1;
 378                 }
 379                 break;
 380         }
 381 }
 382
 383 void
 384 openlog (const char *ident, int logstat, int logfac)
 385 {
 386   /* Protect against multiple users and cancellation.  */
 387   __libc_cleanup_push (cancel_handler, NULL);
 388   __libc_lock_lock (syslog_lock);
 389
 390   openlog_internal (ident, logstat, logfac);
 391
 392   __libc_cleanup_pop (1);
 393 }
 394
 395 #ifndef NO_SIGPIPE
 396 static void
 397 sigpipe_handler (int signo)
 398 {
 399   closelog_internal ();
 400 }
 401 #endif
 402
 403 static void
 404 closelog_internal()
 405 {
 406   if (!connected)
 407     return;
 408
 409   __close (LogFile);
 410   LogFile = -1;
 411   connected = 0;
 412 }
 413
 414 void
 415 closelog ()
 416 {
 417   /* Protect against multiple users and cancellation.  */
 418   __libc_cleanup_push (cancel_handler, NULL);
 419   __libc_lock_lock (syslog_lock);
 420
 421   closelog_internal ();
 422   LogTag = NULL;
 423   LogType = SOCK_DGRAM; /* this is the default */
 424
 425   /* Free the lock.  */
 426   __libc_cleanup_pop (1);
 427 }
 428
 429 /* setlogmask -- set the log mask level */
 430 int
 431 setlogmask(pmask)
 432         int pmask;
 433 {
 434         int omask;
 435
 436         omask = LogMask;
 437         if (pmask != 0)
 438                 LogMask = pmask;
 439         return (omask);
 440 }