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