lib/libc/gen/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  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)syslog.c 8.5 (Berkeley) 4/29/95
  34  * $FreeBSD: src/lib/libc/gen/syslog.c,v 1.21.2.3 2002/11/18 11:49:55 ru Exp $
  35  * $DragonFly: src/lib/libc/gen/syslog.c,v 1.9 2005/11/19 22:32:53 swildner Exp $
  36  */
  37
  38 #include "namespace.h"
  39 #include <sys/types.h>
  40 #include <sys/socket.h>
  41 #include <sys/syslog.h>
  42 #include <sys/uio.h>
  43 #include <sys/un.h>
  44 #include <netdb.h>
  45
  46 #include <errno.h>
  47 #include <fcntl.h>
  48 #include <paths.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52 #include <time.h>
  53 #include <unistd.h>
  54 #include "un-namespace.h"
  55
  56 #include <stdarg.h>
  57
  58 static int      LogFile = -1;           /* fd for log */
  59 static int      connected;              /* have done connect */
  60 static int      opened;                 /* have done openlog() */
  61 static int      LogStat = 0;            /* status bits, set by openlog() */
  62 static const char *LogTag = NULL;       /* string to tag the entry with */
  63 static int      LogFacility = LOG_USER; /* default facility code */
  64 static int      LogMask = 0xff;         /* mask of priorities to be logged */
  65
  66 static void     disconnectlog (void); /* disconnect from syslogd */
  67 static void     connectlog (void);      /* (re)connect to syslogd */
  68
  69 /*
  70  * Format of the magic cookie passed through the stdio hook
  71  */
  72 struct bufcookie {
  73         char    *base;  /* start of buffer */
  74         int     left;
  75 };
  76
  77 /*
  78  * stdio write hook for writing to a static string buffer
  79  * XXX: Maybe one day, dynamically allocate it so that the line length
  80  *      is `unlimited'.
  81  */
  82 static int
  83 writehook(void *cookie, const char *buf, int len)
  84 {
  85         struct bufcookie *h;    /* private `handle' */
  86
  87         h = (struct bufcookie *)cookie;
  88         if (len > h->left) {
  89                 /* clip in case of wraparound */
  90                 len = h->left;
  91         }
  92         if (len > 0) {
  93                 memcpy(h->base, buf, len); /* `write' it. */
  94                 h->base += len;
  95                 h->left -= len;
  96         }
  97         return 0;
  98 }
  99
 100 /*
 101  * syslog, vsyslog --
 102  *      print message on log file; output is intended for syslogd(8).
 103  */
 104 void
 105 syslog(int pri, const char *fmt, ...)
 106 {
 107         va_list ap;
 108
 109         va_start(ap, fmt);
 110         vsyslog(pri, fmt, ap);
 111         va_end(ap);
 112 }
 113
 114 void
 115 vsyslog(int pri, const char *fmt, va_list ap)
 116 {
 117         int cnt;
 118         char ch, *p;
 119         time_t now;
 120         int fd, saved_errno;
 121         char *stdp, tbuf[2048], fmt_cpy[1024], timbuf[26];
 122         FILE *fp, *fmt_fp;
 123         struct bufcookie tbuf_cookie;
 124         struct bufcookie fmt_cookie;
 125
 126         stdp = NULL;
 127
 128 #define INTERNALLOG     LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID
 129         /* Check for invalid bits. */
 130         if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {
 131                 syslog(INTERNALLOG,
 132                     "syslog: unknown facility/priority: %x", pri);
 133                 pri &= LOG_PRIMASK|LOG_FACMASK;
 134         }
 135
 136         /* Check priority against setlogmask values. */
 137         if (!(LOG_MASK(LOG_PRI(pri)) & LogMask))
 138                 return;
 139
 140         saved_errno = errno;
 141
 142         /* Set default facility if none specified. */
 143         if ((pri & LOG_FACMASK) == 0)
 144                 pri |= LogFacility;
 145
 146         /* Create the primary stdio hook */
 147         tbuf_cookie.base = tbuf;
 148         tbuf_cookie.left = sizeof(tbuf);
 149         fp = fwopen(&tbuf_cookie, writehook);
 150         if (fp == NULL)
 151                 return;
 152
 153         /* Build the message. */
 154         time(&now);
 155         fprintf(fp, "<%d>", pri);
 156         fprintf(fp, "%.15s ", ctime_r(&now, timbuf) + 4);
 157         if (LogStat & LOG_PERROR) {
 158                 /* Transfer to string buffer */
 159                 fflush(fp);
 160                 stdp = tbuf + (sizeof(tbuf) - tbuf_cookie.left);
 161         }
 162         if (LogTag == NULL)
 163                 LogTag = getprogname();
 164         if (LogTag != NULL)
 165                 fprintf(fp, "%s", LogTag);
 166         if (LogStat & LOG_PID)
 167                 fprintf(fp, "[%d]", getpid());
 168         if (LogTag != NULL) {
 169                 fprintf(fp, ": ");
 170         }
 171
 172         /* Check to see if we can skip expanding the %m */
 173         if (strstr(fmt, "%m")) {
 174
 175                 /* Create the second stdio hook */
 176                 fmt_cookie.base = fmt_cpy;
 177                 fmt_cookie.left = sizeof(fmt_cpy) - 1;
 178                 fmt_fp = fwopen(&fmt_cookie, writehook);
 179                 if (fmt_fp == NULL) {
 180                         fclose(fp);
 181                         return;
 182                 }
 183
 184                 /* Substitute error message for %m. */
 185                 for ( ; (ch = *fmt); ++fmt)
 186                         if (ch == '%' && fmt[1] == 'm') {
 187                                 ++fmt;
 188                                 fputs(strerror(saved_errno), fmt_fp);
 189                         } else
 190                                 fputc(ch, fmt_fp);
 191
 192                 /* Null terminate if room */
 193                 fputc(0, fmt_fp);
 194                 fclose(fmt_fp);
 195
 196                 /* Guarantee null termination */
 197                 fmt_cpy[sizeof(fmt_cpy) - 1] = '\0';
 198
 199                 fmt = fmt_cpy;
 200         }
 201
 202         vfprintf(fp, fmt, ap);
 203         fclose(fp);
 204
 205         cnt = sizeof(tbuf) - tbuf_cookie.left;
 206
 207         /* Output to stderr if requested. */
 208         if (LogStat & LOG_PERROR) {
 209                 struct iovec iov[2];
 210                 struct iovec *v = iov;
 211
 212                 v->iov_base = stdp;
 213                 v->iov_len = cnt - (stdp - tbuf);
 214                 ++v;
 215                 v->iov_base = "\n";
 216                 v->iov_len = 1;
 217                 _writev(STDERR_FILENO, iov, 2);
 218         }
 219
 220         /* Get connected, output the message to the local logger. */
 221         if (!opened)
 222                 openlog(LogTag, LogStat | LOG_NDELAY, 0);
 223         connectlog();
 224         if (send(LogFile, tbuf, cnt, 0) >= 0)
 225                 return;
 226
 227         /*
 228          * If the send() failed, the odds are syslogd was restarted.
 229          * Make one (only) attempt to reconnect to /dev/log.
 230          */
 231         disconnectlog();
 232         connectlog();
 233         if (send(LogFile, tbuf, cnt, 0) >= 0)
 234                 return;
 235
 236         /*
 237          * Output the message to the console; try not to block
 238          * as a blocking console should not stop other processes.
 239          * Make sure the error reported is the one from the syslogd failure.
 240          */
 241         if (LogStat & LOG_CONS &&
 242             (fd = _open(_PATH_CONSOLE, O_WRONLY|O_NONBLOCK, 0)) >= 0) {
 243                 struct iovec iov[2];
 244                 struct iovec *v = iov;
 245
 246                 p = strchr(tbuf, '>') + 1;
 247                 v->iov_base = p;
 248                 v->iov_len = cnt - (p - tbuf);
 249                 ++v;
 250                 v->iov_base = "\r\n";
 251                 v->iov_len = 2;
 252                 _writev(fd, iov, 2);
 253                 _close(fd);
 254         }
 255 }
 256 static void
 257 disconnectlog(void)
 258 {
 259         /*
 260          * If the user closed the FD and opened another in the same slot,
 261          * that's their problem.  They should close it before calling on
 262          * system services.
 263          */
 264         if (LogFile != -1) {
 265                 _close(LogFile);
 266                 LogFile = -1;
 267         }
 268         connected = 0;                  /* retry connect */
 269 }
 270
 271 static void
 272 connectlog(void)
 273 {
 274         struct sockaddr_un SyslogAddr;  /* AF_UNIX address of local logger */
 275
 276         if (LogFile == -1) {
 277                 if ((LogFile = _socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
 278                         return;
 279                 _fcntl(LogFile, F_SETFD, 1);
 280         }
 281         if (LogFile != -1 && !connected) {
 282                 SyslogAddr.sun_len = sizeof(SyslogAddr);
 283                 SyslogAddr.sun_family = AF_UNIX;
 284                 strncpy(SyslogAddr.sun_path, _PATH_LOG,
 285                     sizeof SyslogAddr.sun_path);
 286                 connected = _connect(LogFile, (struct sockaddr *)&SyslogAddr,
 287                         sizeof(SyslogAddr)) != -1;
 288
 289                 if (!connected) {
 290                         /*
 291                          * Try the old "/dev/log" path, for backward
 292                          * compatibility.
 293                          */
 294                         strncpy(SyslogAddr.sun_path, _PATH_OLDLOG,
 295                             sizeof SyslogAddr.sun_path);
 296                         connected = _connect(LogFile,
 297                                 (struct sockaddr *)&SyslogAddr,
 298                                 sizeof(SyslogAddr)) != -1;
 299                 }
 300
 301                 if (!connected) {
 302                         _close(LogFile);
 303                         LogFile = -1;
 304                 }
 305         }
 306 }
 307
 308 void
 309 openlog(const char *ident, int logstat, int logfac)
 310 {
 311         if (ident != NULL)
 312                 LogTag = ident;
 313         LogStat = logstat;
 314         if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
 315                 LogFacility = logfac;
 316
 317         if (LogStat & LOG_NDELAY)       /* open immediately */
 318                 connectlog();
 319
 320         opened = 1;     /* ident and facility has been set */
 321 }
 322
 323 void
 324 closelog(void)
 325 {
 326         _close(LogFile);
 327         LogFile = -1;
 328         LogTag = NULL;
 329         connected = 0;
 330 }
 331
 332 /* setlogmask -- set the log mask level */
 333 int
 334 setlogmask(int pmask)
 335 {
 336         int omask;
 337
 338         omask = LogMask;
 339         if (pmask != 0)
 340                 LogMask = pmask;
 341         return (omask);
 342 }