server/log-syslog.c

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <stdarg.h>
  38 #include <string.h>
  39 #include <errno.h>
  40
  41 #include "internal.h"
  42 #include "open_memstream.h"
  43 #include "syslog.h"
  44
  45 /* Tempted to use LOG_FTP instead of LOG_DAEMON! */
  46 static const int PRIORITY = LOG_DAEMON|LOG_ERR;
  47
  48 /* Note: preserves the previous value of errno. */
  49 void
  50 log_syslog_verror (const char *fs, va_list args)
  51 {
  52   int err = errno;
  53   const char *name = threadlocal_get_name ();
  54   size_t instance_num = threadlocal_get_instance_num ();
  55   CLEANUP_FREE char *msg = NULL;
  56   size_t len = 0;
  57   FILE *fp = NULL;
  58
  59   fp = open_memstream (&msg, &len);
  60   if (fp == NULL) {
  61     /* Fallback to logging using fs, args directly. */
  62     errno = err; /* Must restore in case fs contains %m */
  63     vsyslog (PRIORITY, fs, args);
  64     goto out;
  65   }
  66
  67   if (name) {
  68     fprintf (fp, "%s", name);
  69     if (instance_num > 0)
  70       fprintf (fp, "[%zu]", instance_num);
  71     fprintf (fp, ": ");
  72   }
  73
  74   errno = err; /* Must restore in case fs contains %m */
  75   vfprintf (fp, fs, args);
  76   close_memstream (fp);
  77
  78   syslog (PRIORITY, "%s", msg);
  79
  80  out:
  81   errno = err;
  82 }