usr/src/cmd/cmd-inet/usr.bin/dns-sd/ClientCommon.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2008-2011 Apple Inc. All rights reserved.
   4  *
   5  * Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Inc.
   6  * ("Apple") in consideration of your agreement to the following terms, and your
   7  * use, installation, modification or redistribution of this Apple software
   8  * constitutes acceptance of these terms.  If you do not agree with these terms,
   9  * please do not use, install, modify or redistribute this Apple software.
  10  *
  11  * In consideration of your agreement to abide by the following terms, and subject
  12  * to these terms, Apple grants you a personal, non-exclusive license, under Apple's
  13  * copyrights in this original Apple software (the "Apple Software"), to use,
  14  * reproduce, modify and redistribute the Apple Software, with or without
  15  * modifications, in source and/or binary forms; provided that if you redistribute
  16  * the Apple Software in its entirety and without modifications, you must retain
  17  * this notice and the following text and disclaimers in all such redistributions of
  18  * the Apple Software.  Neither the name, trademarks, service marks or logos of
  19  * Apple Inc. may be used to endorse or promote products derived from the
  20  * Apple Software without specific prior written permission from Apple.  Except as
  21  * expressly stated in this notice, no other rights or licenses, express or implied,
  22  * are granted by Apple herein, including but not limited to any patent rights that
  23  * may be infringed by your derivative works or by other works in which the Apple
  24  * Software may be incorporated.
  25  *
  26  * The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO
  27  * WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
  28  * WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  29  * PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
  30  * COMBINATION WITH YOUR PRODUCTS.
  31  *
  32  * IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
  33  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  34  * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION
  36  * OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT
  37  * (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN
  38  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  39  */
  40
  41 #include <ctype.h>
  42 #include <stdio.h>          // For stdout, stderr
  43
  44 #include "ClientCommon.h"
  45
  46 const char *GetNextLabel(const char *cstr, char label[64])
  47 {
  48     char *ptr = label;
  49     while (*cstr && *cstr != '.')               // While we have characters in the label...
  50     {
  51         char c = *cstr++;
  52         if (c == '\\' && *cstr)                 // If we have a backslash, and it's not the last character of the string
  53         {
  54             c = *cstr++;
  55             if (isdigit(cstr[-1]) && isdigit(cstr[0]) && isdigit(cstr[1]))
  56             {
  57                 int v0 = cstr[-1] - '0';                        // then interpret as three-digit decimal
  58                 int v1 = cstr[ 0] - '0';
  59                 int v2 = cstr[ 1] - '0';
  60                 int val = v0 * 100 + v1 * 10 + v2;
  61                 // If valid three-digit decimal value, use it
  62                 // Note that although ascii nuls are possible in DNS labels
  63                 // we're building a C string here so we have no way to represent that
  64                 if (val == 0) val = '-';
  65                 if (val <= 255) { c = (char)val; cstr += 2; }
  66             }
  67         }
  68         *ptr++ = c;
  69         if (ptr >= label+64) { label[63] = 0; return(NULL); }   // Illegal label more than 63 bytes
  70     }
  71     *ptr = 0;                                                   // Null-terminate label text
  72     if (ptr == label) return(NULL);                             // Illegal empty label
  73     if (*cstr) cstr++;                                          // Skip over the trailing dot (if present)
  74     return(cstr);
  75 }