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/*
* DEBUG: section 20 Storage Manager Swapfile Unpacker
* AUTHOR: Robert Collins
*
* SQUID Web Proxy Cache http://www.squid-cache.org/
* ----------------------------------------------------------
*
* Squid is the result of efforts by numerous individuals from
* the Internet community; see the CONTRIBUTORS file for full
* details. Many organizations have provided support for Squid's
* development; see the SPONSORS file for full details. Squid is
* Copyrighted (C) 2001 by the Regents of the University of
* California; see the COPYRIGHT file for full details. Squid
* incorporates software developed and/or copyrighted by other
* sources; see the CREDITS file for full details.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
*
*/
#include "squid.h"
#include "defines.h"
#include "Debug.h"
#include "StoreMetaUnpacker.h"
#include "StoreMeta.h"
int const StoreMetaUnpacker::MinimumBufferLength = sizeof(char) + sizeof(int);
/// useful for meta stored in pre-initialized (with zeros) db files
bool
StoreMetaUnpacker::isBufferZero()
{
// We could memcmp the entire buffer, but it is probably safe enough
// to test a few bytes because if we do not detect a corrupted entry
// it is not a big deal. Empty entries are not isBufferSane anyway.
const int depth = 10;
if (buflen < depth)
return false; // cannot be sure enough
for (int i = 0; i < depth; ++i) {
if (buf[i])
return false;
}
return true;
}
bool
StoreMetaUnpacker::isBufferSane()
{
if (buf[0] != (char) STORE_META_OK)
return false;
/*
* sanity check on 'buflen' value. It should be at least big
* enough to hold one type and one length.
*/
getBufferLength();
if (*hdr_len < MinimumBufferLength)
return false;
if (*hdr_len > buflen)
return false;
return true;
}
void
StoreMetaUnpacker::getBufferLength()
{
memcpy(hdr_len, &buf[1], sizeof(int));
}
StoreMetaUnpacker::StoreMetaUnpacker (char const *aBuffer, ssize_t aLen, int *anInt) : buf (aBuffer), buflen(aLen), hdr_len(anInt), position(1 + sizeof(int))
{
assert (aBuffer != NULL);
}
void
StoreMetaUnpacker::getType()
{
type = buf[position];
++position;
}
void
StoreMetaUnpacker::getLength()
{
memcpy(&length, &buf[position], sizeof(int));
position += sizeof(int);
}
bool
StoreMetaUnpacker::doOneEntry()
{
getType();
getLength();
if (position + length > *hdr_len) {
debugs(20, DBG_CRITICAL, "storeSwapMetaUnpack: overflow!");
debugs(20, DBG_CRITICAL, "\ttype=" << type << ", length=" << length << ", *hdr_len=" << *hdr_len << ", offset=" << position);
return false;
}
StoreMeta *newNode = StoreMeta::Factory(type, length, &buf[position]);
if (newNode)
tail = StoreMeta::Add (tail, newNode);
position += length;
return true;
}
bool
StoreMetaUnpacker::moreToProcess() const
{
return *hdr_len - position - MinimumBufferLength >= 0;
}
StoreMeta *
StoreMetaUnpacker::createStoreMeta ()
{
tlv *TLV = NULL;
tail = &TLV;
assert(hdr_len != NULL);
if (!isBufferSane())
return NULL;
getBufferLength();
assert (position == 1 + sizeof(int));
while (moreToProcess()) {
if (!doOneEntry())
break;
}
return TLV;
}
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