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