src/StoreMetaUnpacker.cc

   1
   2 /*
   3  * $Id$
   4  *
   5  * DEBUG: section 20    Storage Manager Swapfile Unpacker
   6  * AUTHOR: Robert Collins
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   9  * ----------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from
  12  *  the Internet community; see the CONTRIBUTORS file for full
  13  *  details.   Many organizations have provided support for Squid's
  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
  16  *  California; see the COPYRIGHT file for full details.  Squid
  17  *  incorporates software developed and/or copyrighted by other
  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "squid.h"
  37 #include "StoreMetaUnpacker.h"
  38 #include "StoreMeta.h"
  39
  40 int const StoreMetaUnpacker::MinimumBufferLength = sizeof(char) + sizeof(int);
  41
  42 bool
  43 StoreMetaUnpacker::isBufferSane()
  44 {
  45     if (buf[0] != (char) STORE_META_OK)
  46         return false;
  47
  48     /*
  49      * sanity check on 'buflen' value.  It should be at least big
  50      * enough to hold one type and one length.
  51      */
  52     getBufferLength();
  53
  54     if (*hdr_len < MinimumBufferLength)
  55         return false;
  56
  57     if (*hdr_len > buflen)
  58         return false;
  59
  60     return true;
  61 }
  62
  63 void
  64 StoreMetaUnpacker::getBufferLength()
  65 {
  66     xmemcpy(hdr_len, &buf[1], sizeof(int));
  67 }
  68
  69 StoreMetaUnpacker::StoreMetaUnpacker (char const *aBuffer, ssize_t aLen, int *anInt) : buf (aBuffer), buflen(aLen), hdr_len(anInt), position(1 + sizeof(int))
  70 {
  71     assert (aBuffer != NULL);
  72 }
  73
  74 void
  75 StoreMetaUnpacker::getType()
  76 {
  77     type = buf[position++];
  78 }
  79
  80 void
  81 StoreMetaUnpacker::getLength()
  82 {
  83     xmemcpy(&length, &buf[position], sizeof(int));
  84     position += sizeof(int);
  85 }
  86
  87 bool
  88 StoreMetaUnpacker::doOneEntry()
  89 {
  90     getType();
  91     getLength();
  92
  93     if (position + length > *hdr_len) {
  94         debugs(20, 0, "storeSwapMetaUnpack: overflow!");
  95         debugs(20, 0, "\ttype=" << type << ", length=" << length << ", *hdr_len=" << *hdr_len << ", offset=" << position);
  96         return false;
  97     }
  98
  99     StoreMeta *newNode = StoreMeta::Factory(type, length, &buf[position]);
 100
 101     if (newNode)
 102         tail = StoreMeta::Add (tail, newNode);
 103
 104     position += length;
 105
 106     return true;
 107 }
 108
 109 bool
 110 StoreMetaUnpacker::moreToProcess() const
 111 {
 112     return *hdr_len - position - MinimumBufferLength >= 0;
 113 }
 114
 115 StoreMeta *
 116 StoreMetaUnpacker::createStoreMeta ()
 117 {
 118     tlv *TLV = NULL;
 119     tail = &TLV;
 120     assert(hdr_len != NULL);
 121
 122     if (!isBufferSane())
 123         return NULL;
 124
 125     getBufferLength();
 126
 127     assert (position == 1 + sizeof(int));
 128
 129     while (moreToProcess()) {
 130         if (!doOneEntry())
 131             break;
 132     }
 133
 134     return TLV;
 135 }