/*

 * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998

 *  The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *  This product includes software developed by the Computer Systems

 *  Engineering Group at Lawrence Berkeley Laboratory.

 * 4. Neither the name of the University nor of the Laboratory may be used

 *    to endorse or promote products derived from this software without

 *    specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

/*

 * Utilities for message formatting used both by libpcap and rpcapd.

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include "ftmacros.h"

#include <stddef.h>

#include <stdarg.h>

#include <stdio.h>

#include <string.h>

#include <errno.h>

#include "pcap-int.h"

#include "portability.h"

#include "fmtutils.h"

#ifdef _WIN32

#include "charconv.h"

#endif

/*

 * Set the encoding.

 */

#ifdef _WIN32

/*

 * True if we shouold use UTF-8.

 */

static int use_utf_8;

void

pcap_fmt_set_encoding(unsigned int opts)

{

  if (opts == PCAP_CHAR_ENC_UTF_8)

    use_utf_8 = 1;

}

#else

void

pcap_fmt_set_encoding(unsigned int opts _U_)

{

  /*

   * Nothing to do here.

   */

}

#endif

#ifdef _WIN32

/*

 * Convert a null-terminated UTF-16LE string to UTF-8, putting it into

 * a buffer starting at the specified location and stopping if we go

 * past the specified size.  This will only put out complete UTF-8

 * sequences.

 *

 * We do this ourselves because Microsoft doesn't offer a "convert and

 * stop at a UTF-8 character boundary if we run out of space" routine.

 */

#define IS_LEADING_SURROGATE(c) \

  ((c) >= 0xd800 && (c) < 0xdc00)

#define IS_TRAILING_SURROGATE(c) \

  ((c) >= 0xdc00 && (c) < 0xe000)

#define SURROGATE_VALUE(leading, trailing) \

  (((((leading) - 0xd800) << 10) | ((trailing) - 0xdc00)) + 0x10000)

#define REPLACEMENT_CHARACTER 0x0FFFD

static char *

utf_16le_to_utf_8_truncated(const wchar_t *utf_16, char *utf_8,

    size_t utf_8_len)

{

  wchar_t c, c2;

  uint32_t uc;

  if (utf_8_len == 0) {

    /*

     * Not even enough room for a trailing '\0'.

     * Don't put anything into the buffer.

     */

    return (utf_8);

  }

  while ((c = *utf_16++) != '\0') {

    if (IS_LEADING_SURROGATE(c)) {

      /*

       * Leading surrogate.  Must be followed by

       * a trailing surrogate.

       */

      c2 = *utf_16;

      if (c2 == '\0') {

        /*

         * Oops, string ends with a lead

         * surrogate.  Try to drop in

         * a REPLACEMENT CHARACTER, and

         * don't move the string pointer,

         * so on the next trip through

         * the loop we grab the terminating

         * '\0' and quit.

         */

        uc = REPLACEMENT_CHARACTER;

      } else {

        /*

         * OK, we can consume this 2-octet

         * value.

         */

        utf_16++;

        if (IS_TRAILING_SURROGATE(c2)) {

          /*

           * Trailing surrogate.

           * This calculation will,

           * for c being a leading

           * surrogate and c2 being

           * a trailing surrogate,

           * produce a value between

           * 0x100000 and 0x10ffff,

           * so it's always going to be

           * a valid Unicode code point.

           */

          uc = SURROGATE_VALUE(c, c2);

        } else {

          /*

           * Not a trailing surroage;

           * try to drop in a

           * REPLACEMENT CHARACTER.

           */

          uc = REPLACEMENT_CHARACTER;

        }

      }

    } else {

      /*

       * Not a leading surrogate.

       */

      if (IS_TRAILING_SURROGATE(c)) {

        /*

         * Trailing surrogate without

         * a preceding leading surrogate.

         * Try to drop in a REPLACEMENT

         * CHARACTER.

         */

        uc = REPLACEMENT_CHARACTER;

      } else {

        /*

         * This is a valid BMP character;

         * drop it in.

         */

        uc = c;

      }

    }

    /*

     * OK, uc is a valid Unicode character; how

     * many bytes worth of UTF-8 does it require?

     */

    if (uc < 0x0080) {

      /* 1 byte. */

      if (utf_8_len < 2) {

        /*

         * Not enough room for that byte

         * plus a trailing '\0'.

         */

        break;

      }

      *utf_8++ = (char)uc;

      utf_8_len--;

    } else if (uc < 0x0800) {

      /* 2 bytes. */

      if (utf_8_len < 3) {

        /*

         * Not enough room for those bytes

         * plus a trailing '\0'.

         */

        break;

      }

      *utf_8++ = ((uc >> 6) & 0x3F) | 0xC0;

      *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;

      utf_8_len -= 2;

    } else if (uc < 0x010000) {

      /* 3 bytes. */

      if (utf_8_len < 4) {

        /*

         * Not enough room for those bytes

         * plus a trailing '\0'.

         */

        break;

      }

      *utf_8++ = ((uc >> 12) & 0x0F) | 0xE0;

      *utf_8++ = ((uc >> 6) & 0x3F) | 0x80;

      *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;

      utf_8_len -= 3;

    } else {

      /* 4 bytes. */

      if (utf_8_len < 5) {

        /*

         * Not enough room for those bytes

         * plus a trailing '\0'.

         */

        break;

      }

      *utf_8++ = ((uc >> 18) & 0x03) | 0xF0;

      *utf_8++ = ((uc >> 12) & 0x3F) | 0x80;

      *utf_8++ = ((uc >> 6) & 0x3F) | 0x80;

      *utf_8++ = ((uc >> 0) & 0x3F) | 0x80;

      utf_8_len -= 3;

    }

  }

  /*

   * OK, we have enough room for (at least) a trailing '\0'.

   * (We started out with enough room, thanks to the test

   * for a zero-length buffer at the beginning, and if

   * there wasn't enough room for any character we wanted

   * to put into the buffer *plus* a trailing '\0',

   * we'd have quit before putting it into the buffer,

   * and thus would have left enough room for the trailing

   * '\0'.)

   *

   * Drop it in.

   */

  *utf_8 = '\0';

  /*

   * Return a pointer to the terminating '\0', in case we

   * want to drop something in after that.

   */

  return (utf_8);

}

#endif /* _WIN32 */

/*

 * Generate an error message based on a format, arguments, and an

 * errno, with a message for the errno after the formatted output.

 */

void

pcap_fmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum,

    const char *fmt, ...)

{

  va_list ap;

  va_start(ap, fmt);

  pcap_vfmt_errmsg_for_errno(errbuf, errbuflen, errnum, fmt, ap);

  va_end(ap);

}

void

pcap_vfmt_errmsg_for_errno(char *errbuf, size_t errbuflen, int errnum,

    const char *fmt, va_list ap)

{

  size_t msglen;

  char *p;

  size_t errbuflen_remaining;

  (void)vsnprintf(errbuf, errbuflen, fmt, ap);

  msglen = strlen(errbuf);

  /*

   * Do we have enough space to append ": "?

   * Including the terminating '\0', that's 3 bytes.

   */

  if (msglen + 3 > errbuflen) {

    /* No - just give them what we've produced. */

    return;

  }

  p = errbuf + msglen;

  errbuflen_remaining = errbuflen - msglen;

  *p++ = ':';

  *p++ = ' ';

  *p = '\0';

  errbuflen_remaining -= 2;

  /*

   * Now append the string for the error code.

   */

#if defined(HAVE__WCSERROR_S)

  /*

   * We have a Windows-style _wcserror_s().

   * Generate a UTF-16LE error message.

   */

  wchar_t utf_16_errbuf[PCAP_ERRBUF_SIZE];

  errno_t err = _wcserror_s(utf_16_errbuf, PCAP_ERRBUF_SIZE, errnum);

  if (err != 0) {

    /*

     * It doesn't appear to be documented anywhere obvious

     * what the error returns from _wcserror_s().

     */

    snprintf(p, errbuflen_remaining, "Error %d", errnum);

    return;

  }

  /*

   * Now convert it from UTF-16LE to UTF-8, dropping it in the

   * remaining space in the buffer, and truncating it - cleanly,

   * on a UTF-8 character boundary - if it doesn't fit.

   */

  utf_16le_to_utf_8_truncated(utf_16_errbuf, p, errbuflen_remaining);

  /*

   * Now, if we're not in UTF-8 mode, convert errbuf to the

   * local code page.

   */

  if (!use_utf_8)

    utf_8_to_acp_truncated(errbuf);

#elif defined(HAVE_GNU_STRERROR_R)

  /*

   * We have a GNU-style strerror_r(), which is *not* guaranteed to

   * do anything to the buffer handed to it, and which returns a

   * pointer to the error string, which may or may not be in

   * the buffer.

   *

   * It is, however, guaranteed to succeed.

   */

  char strerror_buf[PCAP_ERRBUF_SIZE];

  char *errstring = strerror_r(errnum, strerror_buf, PCAP_ERRBUF_SIZE);

  snprintf(p, errbuflen_remaining, "%s", errstring);

#elif defined(HAVE_POSIX_STRERROR_R)

  /*

   * We have a POSIX-style strerror_r(), which is guaranteed to fill

   * in the buffer, but is not guaranteed to succeed.

   */

  int err = strerror_r(errnum, p, errbuflen_remaining);

  if (err == EINVAL) {

    /*

     * UNIX 03 says this isn't guaranteed to produce a

     * fallback error message.

     */

    snprintf(p, errbuflen_remaining, "Unknown error: %d",

        errnum);

  } else if (err == ERANGE) {

    /*

     * UNIX 03 says this isn't guaranteed to produce a

     * fallback error message.

     */

    snprintf(p, errbuflen_remaining,

        "Message for error %d is too long", errnum);

  }

#else

  /*

   * We have neither _wcserror_s() nor strerror_r(), so we're

   * stuck with using pcap_strerror().

   */

  snprintf(p, errbuflen_remaining, "%s", pcap_strerror(errnum));

#endif

}

#ifdef _WIN32

/*

 * Generate an error message based on a format, arguments, and a

 * Win32 error, with a message for the Win32 error after the formatted output.

 */

void

pcap_fmt_errmsg_for_win32_err(char *errbuf, size_t errbuflen, DWORD errnum,

    const char *fmt, ...)

{

  va_list ap;

  va_start(ap, fmt);

  pcap_vfmt_errmsg_for_win32_err(errbuf, errbuflen, errnum, fmt, ap);

  va_end(ap);

}

void

pcap_vfmt_errmsg_for_win32_err(char *errbuf, size_t errbuflen, DWORD errnum,

    const char *fmt, va_list ap)

{

  size_t msglen;

  char *p;

  size_t errbuflen_remaining;

  DWORD retval;

  wchar_t utf_16_errbuf[PCAP_ERRBUF_SIZE];

  size_t utf_8_len;

  vsnprintf(errbuf, errbuflen, fmt, ap);

  msglen = strlen(errbuf);

  /*

   * Do we have enough space to append ": "?

   * Including the terminating '\0', that's 3 bytes.

   */

  if (msglen + 3 > errbuflen) {

    /* No - just give them what we've produced. */

    return;

  }

  p = errbuf + msglen;

  errbuflen_remaining = errbuflen - msglen;

  *p++ = ':';

  *p++ = ' ';

  *p = '\0';

  msglen += 2;

  errbuflen_remaining -= 2;

  /*

   * Now append the string for the error code.

   *

   * XXX - what language ID to use?

   *

   * For UN*Xes, pcap_strerror() may or may not return localized

   * strings.

   *

   * We currently don't have localized messages for libpcap, but

   * we might want to do so.  On the other hand, if most of these

   * messages are going to be read by libpcap developers and

   * perhaps by developers of libpcap-based applications, English

   * might be a better choice, so the developer doesn't have to

   * get the message translated if it's in a language they don't

   * happen to understand.

   */

  retval = FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS|FORMAT_MESSAGE_MAX_WIDTH_MASK,

      NULL, errnum, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),

      utf_16_errbuf, PCAP_ERRBUF_SIZE, NULL);

  if (retval == 0) {

    /*

     * Failed.

     */

    snprintf(p, errbuflen_remaining,

        "Couldn't get error message for error (%lu)", errnum);

    return;

  }

  /*

   * Now convert it from UTF-16LE to UTF-8.

   */

  p = utf_16le_to_utf_8_truncated(utf_16_errbuf, p, errbuflen_remaining);

  /*

   * Now append the error number, if it fits.

   */

  utf_8_len = p - errbuf;

  errbuflen_remaining -= utf_8_len;

  if (utf_8_len == 0) {

    /* The message was empty. */

    snprintf(p, errbuflen_remaining, "(%lu)", errnum);

  } else

    snprintf(p, errbuflen_remaining, " (%lu)", errnum);

  /*

   * Now, if we're not in UTF-8 mode, convert errbuf to the

   * local code page.

   */

  if (!use_utf_8)

    utf_8_to_acp_truncated(errbuf);

}

#endif