The Tcpdump Group git mirrors - libpcap/blob - fmtutils.c

   1 /*
   2  * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998
   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 Computer Systems
  16  *      Engineering Group at Lawrence Berkeley Laboratory.
  17  * 4. Neither the name of the University nor of the Laboratory may be used
  18  *    to endorse or promote products derived from this software without
  19  *    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
  34 /*
  35  * Utilities for message formatting used both by libpcap and rpcapd.
  36  */
  37
  38 #ifdef HAVE_CONFIG_H
  39 #include <config.h>
  40 #endif
  41
  42 #include "ftmacros.h"
  43
  44 #include <stddef.h>
  45 #include <stdarg.h>
  46 #include <stdio.h>
  47 #include <string.h>
  48 #include <errno.h>
  49
  50 #include <pcap/pcap.h>
  51
  52 #include "portability.h"
  53
  54 #include "fmtutils.h"
  55
  56 /*
  57  * Generate an error message based on a format, arguments, and an
  58  * errno, with a message for the errno after the formatted output.
  59  */
  60 void
  61 pcap_fmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum,
  62     const char *fmt, ...)
  63 {
  64         va_list ap;
  65         size_t msglen;
  66         char *p;
  67         size_t errbuflen_remaining;
  68 #if defined(HAVE_STRERROR_S)
  69         errno_t err;
  70 #elif defined(HAVE_STRERROR_R)
  71         int err;
  72 #endif
  73
  74         va_start(ap, fmt);
  75         pcap_vsnprintf(errbuf, errbuflen, fmt, ap);
  76         va_end(ap);
  77         msglen = strlen(errbuf);
  78
  79         /*
  80          * Do we have enough space to append ": "?
  81          * Including the terminating '\0', that's 3 bytes.
  82          */
  83         if (msglen + 3 > errbuflen) {
  84                 /* No - just give them what we've produced. */
  85                 return;
  86         }
  87         p = errbuf + msglen;
  88         errbuflen_remaining = errbuflen - msglen;
  89         *p++ = ':';
  90         *p++ = ' ';
  91         *p = '\0';
  92         msglen += 2;
  93         errbuflen_remaining -= 2;
  94
  95         /*
  96          * Now append the string for the error code.
  97          */
  98 #if defined(HAVE_STRERROR_S)
  99         err = strerror_s(p, errbuflen_remaining, errnum);
 100         if (err != 0) {
 101                 /*
 102                  * It doesn't appear to be documented anywhere obvious
 103                  * what the error returns from strerror_s().
 104                  */
 105                 pcap_snprintf(p, errbuflen_remaining, "Error %d", errnum);
 106         }
 107 #elif defined(HAVE_STRERROR_R)
 108         err = strerror_r(errnum, p, errbuflen_remaining);
 109         if (err == EINVAL) {
 110                 /*
 111                  * UNIX 03 says this isn't guaranteed to produce a
 112                  * fallback error message.
 113                  */
 114                 pcap_snprintf(p, errbuflen_remaining, "Unknown error: %d",
 115                     errnum);
 116         } else if (err == ERANGE) {
 117                 /*
 118                  * UNIX 03 says this isn't guaranteed to produce a
 119                  * fallback error message.
 120                  */
 121                 pcap_snprintf(p, errbuflen_remaining,
 122                     "Message for error %d is too long", errnum);
 123         }
 124 #else
 125         /*
 126          * We have neither strerror_s() nor strerror_r(), so we're
 127          * stuck with using pcap_strerror().
 128          */
 129         pcap_snprintf(p, errbuflen_remaining, "%s", pcap_strerror(errnum));
 130 #endif
 131 }