server/log-syslog.c

   1 /* nbdkit
   2  * Copyright (C) 2013-2018 Red Hat Inc.
   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 #include <syslog.h>
  41
  42 #include "internal.h"
  43
  44 /* Tempted to use LOG_FTP instead of LOG_DAEMON! */
  45 static const int PRIORITY = LOG_DAEMON|LOG_ERR;
  46
  47 /* Note: preserves the previous value of errno. */
  48 void
  49 log_syslog_verror (const char *fs, va_list args)
  50 {
  51   int err = errno;
  52   const char *name = threadlocal_get_name ();
  53   size_t instance_num = threadlocal_get_instance_num ();
  54   CLEANUP_FREE char *msg = NULL;
  55   size_t len = 0;
  56   FILE *fp = NULL;
  57
  58   fp = open_memstream (&msg, &len);
  59   if (fp == NULL) {
  60     /* Fallback to logging using fs, args directly. */
  61     errno = err; /* Must restore in case fs contains %m */
  62     vsyslog (PRIORITY, fs, args);
  63     goto out;
  64   }
  65
  66   if (name) {
  67     fprintf (fp, "%s", name);
  68     if (instance_num > 0)
  69       fprintf (fp, "[%zu]", instance_num);
  70     fprintf (fp, ": ");
  71   }
  72
  73   errno = err; /* Must restore in case fs contains %m */
  74   vfprintf (fp, fs, args);
  75   fclose (fp);
  76
  77   syslog (PRIORITY, "%s", msg);
  78
  79  out:
  80   errno = err;
  81 }