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Finally added crc checking for descriptor_tags.

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git-svn-id: file:///srv/svn/repos/haiku/trunk/current@5570 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Tyler Dauwalder
2003-12-04 22:59:51 +00:00
parent 8528b6dc19
commit 04d90c2afa
2 changed files with 40 additions and 8 deletions
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src/add-ons/kernel/file_systems/udf/UdfStructures.cpp
+39 -7
View File
@@ -15,6 +15,7 @@
#include <string.h>
#include "CS0String.h"
#include "Utils.h"
using namespace Udf;
@@ -274,7 +275,7 @@ long_address::dump() const
//----------------------------------------------------------------------
void
descriptor_tag ::dump() const
descriptor_tag::dump() const
{
DUMP_INIT("descriptor_tag");
PRINT(("id: %d (%s)\n", id(), tag_id_to_string(tag_id(id()))));
@@ -290,15 +291,41 @@ descriptor_tag ::dump() const
/*! \brief Calculates the tag's CRC, verifies the tag's checksum, and
verifies the tag's location on the medium.
Note that this function makes the assumption that the descriptor_tag
is the first data member in a larger descriptor structure, the remainder
of which immediately follows the descriptor_tag itself in memory. This
is generally a safe assumption, as long as the entire descriptor (and
not the its tag) is read in before init_check() is called. If this is
not the case, it's best to call this function with a \a calculateCrc
value of false, to keep from trying to calculate a crc value on invalid
and possibly unowned memory.
\param block The block location of this descriptor as taken from the
corresponding allocation descriptor. If the address specifies
a block in a partition, the partition block is the desired
location, not the mapped physical disk block.
\param calculateCrc Whether or not to perform the crc calculation
on the descriptor data following the tag.
\todo Calc the CRC.
*/
status_t
descriptor_tag ::init_check(uint32 diskBlock)
descriptor_tag::init_check(uint32 block, bool calculateCrc)
{
DEBUG_INIT("descriptor_tag");
PRINT(("location (paramater) == %ld\n", diskBlock));
PRINT(("location (in structure) == %ld\n", location()));
status_t error = (diskBlock == location()) ? B_OK : B_NO_INIT;
DEBUG_INIT_ETC("descriptor_tag", ("location: %ld, calculateCrc: %s",
block, bool_to_string(calculateCrc)));
PRINT(("location (paramater) == %ld\n", block));
PRINT(("location (in structure) == %ld\n", location()));
if (calculateCrc) {
PRINT(("crc (calculated) == %d\n",
Udf::calculate_crc(reinterpret_cast<uint8*>(this)+sizeof(descriptor_tag),
crc_length())))
} else {
PRINT(("crc (calculated) == (not calculated)\n"));
}
PRINT(("crc (in structure) == %d\n", crc()));
PRINT(("crc_length (in structure) == %d\n", crc_length()));
status_t error = (block == location()) ? B_OK : B_NO_INIT;
// checksum
if (!error) {
uint32 sum = 0;
@@ -308,7 +335,12 @@ descriptor_tag ::init_check(uint32 diskBlock)
sum += ((uint8*)this)[i];
error = sum % 256 == checksum() ? B_OK : B_NO_INIT;
}
// crc
if (!error && calculateCrc) {
uint16 _crc = Udf::calculate_crc(reinterpret_cast<uint8*>(this)
+ sizeof(descriptor_tag), crc_length());
error = _crc == crc() ? B_OK : B_NO_INIT;
}
RETURN(error);
}
src/add-ons/kernel/file_systems/udf/UdfStructures.h
+1 -1
View File
@@ -428,7 +428,7 @@ struct descriptor_tag {
public:
void dump() const;
status_t init_check(uint32 diskBlock);
status_t init_check(uint32 block, bool calculateCrc = true);
uint16 id() const { return B_LENDIAN_TO_HOST_INT16(_id); }
uint16 version() const { return B_LENDIAN_TO_HOST_INT16(_version); }