lib/roken/vsyslog.c

   1 /*
   2  * Copyright (c) 1995 - 2000 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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
  34 #include <config.h>
  35
  36 #ifndef HAVE_VSYSLOG
  37
  38 #include <stdio.h>
  39 #include <syslog.h>
  40 #include <stdarg.h>
  41
  42 #include "roken.h"
  43
  44 /*
  45  * the theory behind this is that we might be trying to call vsyslog
  46  * when there's no memory left, and we should try to be as useful as
  47  * possible.  And the format string should say something about what's
  48  * failing.
  49  */
  50
  51 static void
  52 simple_vsyslog(int pri, const char *fmt, va_list ap)
  53 {
  54     syslog (pri, "%s", fmt);
  55 }
  56
  57 /*
  58  * do like syslog but with a `va_list'
  59  */
  60
  61 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
  62 vsyslog(int pri, const char *fmt, va_list ap)
  63 {
  64     char *fmt2;
  65     const char *p;
  66     char *p2;
  67     int saved_errno = errno;
  68     int fmt_len  = strlen (fmt);
  69     int fmt2_len = fmt_len;
  70     char *buf;
  71
  72     fmt2 = malloc (fmt_len + 1);
  73     if (fmt2 == NULL) {
  74         simple_vsyslog (pri, fmt, ap);
  75         return;
  76     }
  77
  78     for (p = fmt, p2 = fmt2; *p != '\0'; ++p) {
  79         if (p[0] == '%' && p[1] == 'm') {
  80             const char *e = strerror (saved_errno);
  81             int e_len = strlen (e);
  82             char *tmp;
  83             int pos;
  84
  85             pos = p2 - fmt2;
  86             fmt2_len += e_len - 2;
  87             tmp = realloc (fmt2, fmt2_len + 1);
  88             if (tmp == NULL) {
  89                 free (fmt2);
  90                 simple_vsyslog (pri, fmt, ap);
  91                 return;
  92             }
  93             fmt2 = tmp;
  94             p2   = fmt2 + pos;
  95             memmove (p2, e, e_len);
  96             p2 += e_len;
  97             ++p;
  98         } else
  99             *p2++ = *p;
 100     }
 101     *p2 = '\0';
 102
 103     vasprintf (&buf, fmt2, ap);
 104     free (fmt2);
 105     if (buf == NULL) {
 106         simple_vsyslog (pri, fmt, ap);
 107         return;
 108     }
 109     syslog (pri, "%s", buf);
 110     free (buf);
 111 }
 112 #endif