Coverage Report

Created: 2024-07-23 06:08

/src/libpcap/fmtutils.c
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/*
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 * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998
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 *  The Regents of the University of California.  All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *  This product includes software developed by the Computer Systems
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 *  Engineering Group at Lawrence Berkeley Laboratory.
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 * 4. Neither the name of the University nor of the Laboratory may be used
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 *    to endorse or promote products derived from this software without
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 *    specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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/*
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 * Utilities for message formatting used both by libpcap and rpcapd.
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 */
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#include <config.h>
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#include "ftmacros.h"
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#include <stddef.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include "pcap-int.h"
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#include "portability.h"
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#include "fmtutils.h"
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#ifdef _WIN32
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#include "charconv.h"
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#endif
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/*
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 * Set the encoding.
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 */
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#ifdef _WIN32
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/*
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 * True if we should use UTF-8.
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 */
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static int use_utf_8;
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void
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pcapint_fmt_set_encoding(unsigned int opts)
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{
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  if (opts == PCAP_CHAR_ENC_UTF_8)
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    use_utf_8 = 1;
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}
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#else
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void
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pcapint_fmt_set_encoding(unsigned int opts _U_)
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0
{
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  /*
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   * Nothing to do here.
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   */
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0
}
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#endif
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#ifdef _WIN32
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/*
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 * Convert a null-terminated UTF-16LE string to UTF-8, putting it into
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 * a buffer starting at the specified location and stopping if we go
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 * past the specified size.  This will only put out complete UTF-8
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 * sequences.
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 *
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 * We do this ourselves because Microsoft doesn't offer a "convert and
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 * stop at a UTF-8 character boundary if we run out of space" routine.
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 */
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#define IS_LEADING_SURROGATE(c) \
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  ((c) >= 0xd800 && (c) < 0xdc00)
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#define IS_TRAILING_SURROGATE(c) \
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  ((c) >= 0xdc00 && (c) < 0xe000)
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#define SURROGATE_VALUE(leading, trailing) \
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  (((((leading) - 0xd800) << 10) | ((trailing) - 0xdc00)) + 0x10000)
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#define REPLACEMENT_CHARACTER 0x0FFFD
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static char *
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utf_16le_to_utf_8_truncated(const wchar_t *utf_16, char *utf_8,
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    size_t utf_8_len)
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{
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  wchar_t c, c2;
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  uint32_t uc;
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  if (utf_8_len == 0) {
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    /*
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     * Not even enough room for a trailing '\0'.
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     * Don't put anything into the buffer.
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     */
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    return (utf_8);
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  }
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  while ((c = *utf_16++) != '\0') {
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    if (IS_LEADING_SURROGATE(c)) {
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      /*
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       * Leading surrogate.  Must be followed by
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       * a trailing surrogate.
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       */
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      c2 = *utf_16;
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      if (c2 == '\0') {
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        /*
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         * Oops, string ends with a lead
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         * surrogate.  Try to drop in
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         * a REPLACEMENT CHARACTER, and
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         * don't move the string pointer,
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         * so on the next trip through
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         * the loop we grab the terminating
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         * '\0' and quit.
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         */
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        uc = REPLACEMENT_CHARACTER;
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      } else {
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        /*
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         * OK, we can consume this 2-octet
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         * value.
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         */
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        utf_16++;
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        if (IS_TRAILING_SURROGATE(c2)) {
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          /*
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           * Trailing surrogate.
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           * This calculation will,
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           * for c being a leading
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           * surrogate and c2 being
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           * a trailing surrogate,
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           * produce a value between
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           * 0x100000 and 0x10ffff,
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           * so it's always going to be
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           * a valid Unicode code point.
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           */
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          uc = SURROGATE_VALUE(c, c2);
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        } else {
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          /*
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           * Not a trailing surrogate;
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           * try to drop in a
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           * REPLACEMENT CHARACTER.
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           */
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          uc = REPLACEMENT_CHARACTER;
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        }
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      }
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    } else {
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      /*
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       * Not a leading surrogate.
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       */
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      if (IS_TRAILING_SURROGATE(c)) {
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        /*
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         * Trailing surrogate without
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         * a preceding leading surrogate.
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         * Try to drop in a REPLACEMENT
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         * CHARACTER.
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         */
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        uc = REPLACEMENT_CHARACTER;
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      } else {
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        /*
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         * This is a valid BMP character;
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         * drop it in.
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         */
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        uc = c;
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      }
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    }
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    /*
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     * OK, uc is a valid Unicode character; how
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     * many bytes worth of UTF-8 does it require?
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     */
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    if (uc < 0x0080) {
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      /* 1 byte. */
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      if (utf_8_len < 2) {
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        /*
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         * Not enough room for that byte
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         * plus a trailing '\0'.
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         */
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        break;
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      }
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      *utf_8++ = (char)uc;
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      utf_8_len--;
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    } else if (uc < 0x0800) {
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      /* 2 bytes. */
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      if (utf_8_len < 3) {
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        /*
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         * Not enough room for those bytes
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         * plus a trailing '\0'.
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         */
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        break;
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      }
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      *utf_8++ = ((uc >> 6) & 0x3F) | 0xC0;
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      *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;
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      utf_8_len -= 2;
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    } else if (uc < 0x010000) {
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      /* 3 bytes. */
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      if (utf_8_len < 4) {
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        /*
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         * Not enough room for those bytes
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         * plus a trailing '\0'.
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         */
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        break;
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      }
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      *utf_8++ = ((uc >> 12) & 0x0F) | 0xE0;
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      *utf_8++ = ((uc >> 6) & 0x3F) | 0x80;
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      *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;
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      utf_8_len -= 3;
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    } else {
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      /* 4 bytes. */
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      if (utf_8_len < 5) {
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        /*
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         * Not enough room for those bytes
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         * plus a trailing '\0'.
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         */
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        break;
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      }
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      *utf_8++ = ((uc >> 18) & 0x03) | 0xF0;
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      *utf_8++ = ((uc >> 12) & 0x3F) | 0x80;
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      *utf_8++ = ((uc >> 6) & 0x3F) | 0x80;
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      *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;
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      utf_8_len -= 3;
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    }
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  }
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  /*
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   * OK, we have enough room for (at least) a trailing '\0'.
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   * (We started out with enough room, thanks to the test
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   * for a zero-length buffer at the beginning, and if
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   * there wasn't enough room for any character we wanted
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   * to put into the buffer *plus* a trailing '\0',
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   * we'd have quit before putting it into the buffer,
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   * and thus would have left enough room for the trailing
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   * '\0'.)
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   *
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   * Drop it in.
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   */
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  *utf_8 = '\0';
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  /*
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   * Return a pointer to the terminating '\0', in case we
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   * want to drop something in after that.
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   */
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  return (utf_8);
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}
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#endif /* _WIN32 */
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/*
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 * Generate an error message based on a format, arguments, and an
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 * errno, with a message for the errno after the formatted output.
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 */
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void
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pcapint_fmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum,
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    const char *fmt, ...)
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0
{
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0
  va_list ap;
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272
0
  va_start(ap, fmt);
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0
  pcapint_vfmt_errmsg_for_errno(errbuf, errbuflen, errnum, fmt, ap);
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0
  va_end(ap);
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0
}
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void
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pcapint_vfmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum,
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    const char *fmt, va_list ap)
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0
{
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0
  size_t msglen;
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0
  char *p;
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0
  size_t errbuflen_remaining;
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285
0
  (void)vsnprintf(errbuf, errbuflen, fmt, ap);
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0
  msglen = strlen(errbuf);
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288
  /*
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   * Do we have enough space to append ": "?
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   * Including the terminating '\0', that's 3 bytes.
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   */
292
0
  if (msglen + 3 > errbuflen) {
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    /* No - just give them what we've produced. */
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0
    return;
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0
  }
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0
  p = errbuf + msglen;
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0
  errbuflen_remaining = errbuflen - msglen;
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0
  *p++ = ':';
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0
  *p++ = ' ';
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0
  *p = '\0';
301
0
  errbuflen_remaining -= 2;
302
303
  /*
304
   * Now append the string for the error code.
305
   */
306
#if defined(HAVE__WCSERROR_S)
307
  /*
308
   * We have a Windows-style _wcserror_s().
309
   * Generate a UTF-16LE error message.
310
   */
311
  wchar_t utf_16_errbuf[PCAP_ERRBUF_SIZE];
312
  errno_t err = _wcserror_s(utf_16_errbuf, PCAP_ERRBUF_SIZE, errnum);
313
  if (err != 0) {
314
    /*
315
     * It doesn't appear to be documented anywhere obvious
316
     * what the error returns from _wcserror_s().
317
     */
318
    snprintf(p, errbuflen_remaining, "Error %d", errnum);
319
    return;
320
  }
321
322
  /*
323
   * Now convert it from UTF-16LE to UTF-8, dropping it in the
324
   * remaining space in the buffer, and truncating it - cleanly,
325
   * on a UTF-8 character boundary - if it doesn't fit.
326
   */
327
  utf_16le_to_utf_8_truncated(utf_16_errbuf, p, errbuflen_remaining);
328
329
  /*
330
   * Now, if we're not in UTF-8 mode, convert errbuf to the
331
   * local code page.
332
   */
333
  if (!use_utf_8)
334
    utf_8_to_acp_truncated(errbuf);
335
#else
336
  /*
337
   * Either Windows without _wcserror_s() or not Windows.  Let pcap_strerror()
338
   * solve the non-UTF-16 part of this problem space.
339
   */
340
0
  snprintf(p, errbuflen_remaining, "%s", pcap_strerror(errnum));
341
0
#endif
342
0
}
343
344
#ifdef _WIN32
345
/*
346
 * Generate an error message based on a format, arguments, and a
347
 * Win32 error, with a message for the Win32 error after the formatted output.
348
 */
349
void
350
pcapint_fmt_errmsg_for_win32_err(char *errbuf, size_t errbuflen, DWORD errnum,
351
    const char *fmt, ...)
352
{
353
  va_list ap;
354
355
  va_start(ap, fmt);
356
  pcapint_vfmt_errmsg_for_win32_err(errbuf, errbuflen, errnum, fmt, ap);
357
  va_end(ap);
358
}
359
360
void
361
pcapint_vfmt_errmsg_for_win32_err(char *errbuf, size_t errbuflen, DWORD errnum,
362
    const char *fmt, va_list ap)
363
{
364
  size_t msglen;
365
  char *p;
366
  size_t errbuflen_remaining;
367
  DWORD retval;
368
  wchar_t utf_16_errbuf[PCAP_ERRBUF_SIZE];
369
  size_t utf_8_len;
370
371
  vsnprintf(errbuf, errbuflen, fmt, ap);
372
  msglen = strlen(errbuf);
373
374
  /*
375
   * Do we have enough space to append ": "?
376
   * Including the terminating '\0', that's 3 bytes.
377
   */
378
  if (msglen + 3 > errbuflen) {
379
    /* No - just give them what we've produced. */
380
    return;
381
  }
382
  p = errbuf + msglen;
383
  errbuflen_remaining = errbuflen - msglen;
384
  *p++ = ':';
385
  *p++ = ' ';
386
  *p = '\0';
387
  msglen += 2;
388
  errbuflen_remaining -= 2;
389
390
  /*
391
   * Now append the string for the error code.
392
   *
393
   * XXX - what language ID to use?
394
   *
395
   * For UN*Xes, pcap_strerror() may or may not return localized
396
   * strings.
397
   *
398
   * We currently don't have localized messages for libpcap, but
399
   * we might want to do so.  On the other hand, if most of these
400
   * messages are going to be read by libpcap developers and
401
   * perhaps by developers of libpcap-based applications, English
402
   * might be a better choice, so the developer doesn't have to
403
   * get the message translated if it's in a language they don't
404
   * happen to understand.
405
   */
406
  retval = FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS|FORMAT_MESSAGE_MAX_WIDTH_MASK,
407
      NULL, errnum, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
408
      utf_16_errbuf, PCAP_ERRBUF_SIZE, NULL);
409
  if (retval == 0) {
410
    /*
411
     * Failed.
412
     */
413
    snprintf(p, errbuflen_remaining,
414
        "Couldn't get error message for error (%lu)", errnum);
415
    return;
416
  }
417
418
  /*
419
   * Now convert it from UTF-16LE to UTF-8.
420
   */
421
  p = utf_16le_to_utf_8_truncated(utf_16_errbuf, p, errbuflen_remaining);
422
423
  /*
424
   * Now append the error number, if it fits.
425
   */
426
  utf_8_len = p - errbuf;
427
  errbuflen_remaining -= utf_8_len;
428
  if (utf_8_len == 0) {
429
    /* The message was empty. */
430
    snprintf(p, errbuflen_remaining, "(%lu)", errnum);
431
  } else
432
    snprintf(p, errbuflen_remaining, " (%lu)", errnum);
433
434
  /*
435
   * Now, if we're not in UTF-8 mode, convert errbuf to the
436
   * local code page.
437
   */
438
  if (!use_utf_8)
439
    utf_8_to_acp_truncated(errbuf);
440
}
441
#endif