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 <stddef.h>
  43 #include <stdarg.h>
  44 #include <stdio.h>
  45 #include <string.h>
  46 #include <errno.h>
  47
  48 #include <pcap/pcap.h>
  49
  50 #include "portability.h"
  51
  52 #include "fmtutils.h"
  53
  54 /*
  55  * Generate an error message based on a format, arguments, and an
  56  * errno, with a message for the errno after the formatted output.
  57  */
  58 void
  59 pcap_fmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum,
  60     const char *fmt, ...)
  61 {
  62         va_list ap;
  63         size_t msglen;
  64         char *p;
  65         size_t errbuflen_remaining;
  66 #if defined(HAVE_STRERROR_S)
  67         errno_t err;
  68 #elif defined(HAVE_STRERROR_R)
  69         int err;
  70 #endif
  71
  72         va_start(ap, fmt);
  73         pcap_vsnprintf(errbuf, errbuflen, fmt, ap);
  74         va_end(ap);
  75         msglen = strlen(errbuf);
  76
  77         /*
  78          * Do we have enough space to append ": "?
  79          * Including the terminating '\0', that's 3 bytes.
  80          */
  81         if (msglen + 3 > errbuflen) {
  82                 /* No - just give them what we've produced. */
  83                 return;
  84         }
  85         p = errbuf + msglen;
  86         errbuflen_remaining = errbuflen - msglen;
  87         *p++ = ':';
  88         *p++ = ' ';
  89         *p = '\0';
  90         msglen += 2;
  91         errbuflen_remaining -= 2;
  92
  93         /*
  94          * Now append the string for the error code.
  95          */
  96 #if defined(HAVE_STRERROR_S)
  97         err = strerror_s(p, errbuflen_remaining, errnum);
  98         if (err != 0) {
  99                 /*
 100                  * It doesn't appear to be documented anywhere obvious
 101                  * what the error returns from strerror_s().
 102                  */
 103                 pcap_snprintf(p, errbuflen_remaining, "Error %d", errnum);
 104         }
 105 #elif defined(HAVE_STRERROR_R)
 106         err = strerror_r(errnum, p, errbuflen_remaining);
 107         if (err == EINVAL) {
 108                 /*
 109                  * UNIX 03 says this isn't guaranteed to produce a
 110                  * fallback error message.
 111                  */
 112                 pcap_snprintf(p, errbuflen_remaining, "Unknown error: %d",
 113                     errnum);
 114         } else if (err == ERANGE) {
 115                 /*
 116                  * UNIX 03 says this isn't guaranteed to produce a
 117                  * fallback error message.
 118                  */
 119                 pcap_snprintf(p, errbuflen_remaining,
 120                     "Message for error %d is too long", errnum);
 121         }
 122 #else
 123         /*
 124          * We have neither strerror_s() nor strerror_r(), so we're
 125          * stuck with using pcap_strerror().
 126          */
 127         pcap_snprintf(p, errbuflen_remaining, "%s", pcap_strerror(errnum));
 128 #endif
 129 }