gecko-dev/netwerk/cache2/CacheFileMetadata.cpp

683 строки
18 KiB
C++

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "CacheLog.h"
#include "CacheFileMetadata.h"
#include "CacheFileIOManager.h"
#include "CacheHashUtils.h"
#include "CacheFileChunk.h"
#include "../cache/nsCacheUtils.h"
#include "mozilla/Telemetry.h"
#include "prnetdb.h"
namespace mozilla {
namespace net {
#define kMinMetadataRead 1024 // TODO find optimal value from telemetry
#define kAlignSize 4096
#define NO_EXPIRATION_TIME 0xFFFFFFFF
NS_IMPL_ISUPPORTS1(CacheFileMetadata, CacheFileIOListener)
CacheFileMetadata::CacheFileMetadata(CacheFileHandle *aHandle, const nsACString &aKey, bool aKeyIsHash)
: mHandle(aHandle)
, mKeyIsHash(aKeyIsHash)
, mHashArray(nullptr)
, mHashArraySize(0)
, mHashCount(0)
, mOffset(-1)
, mBuf(nullptr)
, mBufSize(0)
, mWriteBuf(nullptr)
, mElementsSize(0)
, mIsDirty(false)
{
LOG(("CacheFileMetadata::CacheFileMetadata() [this=%p, handle=%p, key=%s]",
this, aHandle, PromiseFlatCString(aKey).get()));
MOZ_COUNT_CTOR(CacheFileMetadata);
memset(&mMetaHdr, 0, sizeof(CacheFileMetadataHeader));
mMetaHdr.mExpirationTime = NO_EXPIRATION_TIME;
mKey = aKey;
}
CacheFileMetadata::~CacheFileMetadata()
{
LOG(("CacheFileMetadata::~CacheFileMetadata() [this=%p]", this));
MOZ_COUNT_DTOR(CacheFileMetadata);
MOZ_ASSERT(!mListener);
if (mHashArray) {
free(mHashArray);
mHashArray = nullptr;
mHashArraySize = 0;
}
if (mBuf) {
free(mBuf);
mBuf = nullptr;
mBufSize = 0;
}
DoMemoryReport(MemoryUsage());
}
CacheFileMetadata::CacheFileMetadata(const nsACString &aKey)
: mHandle(nullptr)
, mKeyIsHash(false)
, mHashArray(nullptr)
, mHashArraySize(0)
, mHashCount(0)
, mOffset(0)
, mBuf(nullptr)
, mBufSize(0)
, mWriteBuf(nullptr)
, mElementsSize(0)
, mIsDirty(true)
{
LOG(("CacheFileMetadata::CacheFileMetadata() [this=%p, key=%s]",
this, PromiseFlatCString(aKey).get()));
MOZ_COUNT_CTOR(CacheFileMetadata);
memset(&mMetaHdr, 0, sizeof(CacheFileMetadataHeader));
mMetaHdr.mExpirationTime = NO_EXPIRATION_TIME;
mMetaHdr.mFetchCount++;
mKey = aKey;
mMetaHdr.mKeySize = mKey.Length();
}
void
CacheFileMetadata::SetHandle(CacheFileHandle *aHandle)
{
LOG(("CacheFileMetadata::SetHandle() [this=%p, handle=%p]", this, aHandle));
MOZ_ASSERT(!mHandle);
mHandle = aHandle;
}
nsresult
CacheFileMetadata::ReadMetadata(CacheFileMetadataListener *aListener)
{
LOG(("CacheFileMetadata::ReadMetadata() [this=%p, listener=%p]", this, aListener));
MOZ_ASSERT(!mListener);
MOZ_ASSERT(!mHashArray);
MOZ_ASSERT(!mBuf);
MOZ_ASSERT(!mWriteBuf);
nsresult rv;
int64_t size = mHandle->FileSize();
MOZ_ASSERT(size != -1);
if (size == 0) {
// this is a new entry
LOG(("CacheFileMetadata::ReadMetadata() - Filesize == 0, creating empty "
"metadata. [this=%p]", this));
InitEmptyMetadata();
aListener->OnMetadataRead(NS_OK);
return NS_OK;
}
if (size < int64_t(sizeof(CacheFileMetadataHeader) + 2*sizeof(uint32_t))) {
// there must be at least checksum, header and offset
LOG(("CacheFileMetadata::ReadMetadata() - File is corrupted, creating "
"empty metadata. [this=%p, filesize=%lld]", this, size));
InitEmptyMetadata();
aListener->OnMetadataRead(NS_OK);
return NS_OK;
}
// round offset to 4k blocks
int64_t offset = (size / kAlignSize) * kAlignSize;
if (size - offset < kMinMetadataRead && offset > kAlignSize)
offset -= kAlignSize;
mBufSize = size - offset;
mBuf = static_cast<char *>(moz_xmalloc(mBufSize));
DoMemoryReport(MemoryUsage());
LOG(("CacheFileMetadata::ReadMetadata() - Reading metadata from disk, trying "
"offset=%lld, filesize=%lld [this=%p]", offset, size, this));
mListener = aListener;
rv = CacheFileIOManager::Read(mHandle, offset, mBuf, mBufSize, this);
if (NS_FAILED(rv)) {
LOG(("CacheFileMetadata::ReadMetadata() - CacheFileIOManager::Read() failed"
" synchronously, creating empty metadata. [this=%p, rv=0x%08x]",
this, rv));
mListener = nullptr;
InitEmptyMetadata();
aListener->OnMetadataRead(NS_OK);
return NS_OK;
}
return NS_OK;
}
nsresult
CacheFileMetadata::WriteMetadata(uint32_t aOffset,
CacheFileMetadataListener *aListener)
{
LOG(("CacheFileMetadata::WriteMetadata() [this=%p, offset=%d, listener=%p]",
this, aOffset, aListener));
MOZ_ASSERT(!mListener);
MOZ_ASSERT(!mWriteBuf);
nsresult rv;
mIsDirty = false;
mWriteBuf = static_cast<char *>(moz_xmalloc(sizeof(uint32_t) +
mHashCount * sizeof(CacheHashUtils::Hash16_t) +
sizeof(CacheFileMetadataHeader) + mKey.Length() + 1 +
mElementsSize + sizeof(uint32_t)));
char *p = mWriteBuf + sizeof(uint32_t);
memcpy(p, mHashArray, mHashCount * sizeof(CacheHashUtils::Hash16_t));
p += mHashCount * sizeof(CacheHashUtils::Hash16_t);
memcpy(p, &mMetaHdr, sizeof(CacheFileMetadataHeader));
p += sizeof(CacheFileMetadataHeader);
memcpy(p, mKey.get(), mKey.Length());
p += mKey.Length();
*p = 0;
p++;
memcpy(p, mBuf, mElementsSize);
p += mElementsSize;
CacheHashUtils::Hash32_t hash;
hash = CacheHashUtils::Hash(mWriteBuf + sizeof(uint32_t),
p - mWriteBuf - sizeof(uint32_t));
*reinterpret_cast<uint32_t *>(mWriteBuf) = PR_htonl(hash);
*reinterpret_cast<uint32_t *>(p) = PR_htonl(aOffset);
p += sizeof(uint32_t);
mListener = aListener;
rv = CacheFileIOManager::Write(mHandle, aOffset, mWriteBuf, p - mWriteBuf,
true, this);
if (NS_FAILED(rv)) {
LOG(("CacheFileMetadata::WriteMetadata() - CacheFileIOManager::Write() "
"failed synchronously. [this=%p, rv=0x%08x]", this, rv));
mListener = nullptr;
free(mWriteBuf);
mWriteBuf = nullptr;
NS_ENSURE_SUCCESS(rv, rv);
}
DoMemoryReport(MemoryUsage());
return NS_OK;
}
const char *
CacheFileMetadata::GetElement(const char *aKey)
{
const char *data = mBuf;
const char *limit = mBuf + mElementsSize;
while (data < limit) {
// Point to the value part
const char *value = data + strlen(data) + 1;
MOZ_ASSERT(value < limit, "Metadata elements corrupted");
if (strcmp(data, aKey) == 0) {
LOG(("CacheFileMetadata::GetElement() - Key found [this=%p, key=%s]",
this, aKey));
return value;
}
// Skip value part
data = value + strlen(value) + 1;
}
MOZ_ASSERT(data == limit, "Metadata elements corrupted");
LOG(("CacheFileMetadata::GetElement() - Key not found [this=%p, key=%s]",
this, aKey));
return nullptr;
}
nsresult
CacheFileMetadata::SetElement(const char *aKey, const char *aValue)
{
LOG(("CacheFileMetadata::SetElement() [this=%p, key=%s, value=%p]",
this, aKey, aValue));
MarkDirty();
const uint32_t keySize = strlen(aKey) + 1;
char *pos = const_cast<char *>(GetElement(aKey));
if (!aValue) {
// No value means remove the key/value pair completely, if existing
if (pos) {
uint32_t oldValueSize = strlen(pos) + 1;
uint32_t offset = pos - mBuf;
uint32_t remainder = mElementsSize - (offset + oldValueSize);
memmove(pos - keySize, pos + oldValueSize, remainder);
mElementsSize -= keySize + oldValueSize;
}
return NS_OK;
}
const uint32_t valueSize = strlen(aValue) + 1;
uint32_t newSize = mElementsSize + valueSize;
if (pos) {
const uint32_t oldValueSize = strlen(pos) + 1;
const uint32_t offset = pos - mBuf;
const uint32_t remainder = mElementsSize - (offset + oldValueSize);
// Update the value in place
newSize -= oldValueSize;
EnsureBuffer(newSize);
// Move the remainder to the right place
pos = mBuf + offset;
memmove(pos + valueSize, pos + oldValueSize, remainder);
} else {
// allocate new meta data element
newSize += keySize;
EnsureBuffer(newSize);
// Add after last element
pos = mBuf + mElementsSize;
memcpy(pos, aKey, keySize);
pos += keySize;
}
// Update value
memcpy(pos, aValue, valueSize);
mElementsSize = newSize;
return NS_OK;
}
CacheHashUtils::Hash16_t
CacheFileMetadata::GetHash(uint32_t aIndex)
{
MOZ_ASSERT(aIndex < mHashCount);
return PR_ntohs(mHashArray[aIndex]);
}
nsresult
CacheFileMetadata::SetHash(uint32_t aIndex, CacheHashUtils::Hash16_t aHash)
{
LOG(("CacheFileMetadata::SetHash() [this=%p, idx=%d, hash=%x]",
this, aIndex, aHash));
MarkDirty();
MOZ_ASSERT(aIndex <= mHashCount);
if (aIndex > mHashCount) {
return NS_ERROR_INVALID_ARG;
} else if (aIndex == mHashCount) {
if ((aIndex + 1) * sizeof(CacheHashUtils::Hash16_t) > mHashArraySize) {
// reallocate hash array buffer
if (mHashArraySize == 0)
mHashArraySize = 32 * sizeof(CacheHashUtils::Hash16_t);
else
mHashArraySize *= 2;
mHashArray = static_cast<CacheHashUtils::Hash16_t *>(
moz_xrealloc(mHashArray, mHashArraySize));
}
mHashCount++;
}
mHashArray[aIndex] = PR_htons(aHash);
DoMemoryReport(MemoryUsage());
return NS_OK;
}
nsresult
CacheFileMetadata::SetExpirationTime(uint32_t aExpirationTime)
{
LOG(("CacheFileMetadata::SetExpirationTime() [this=%p, expirationTime=%d]",
this, aExpirationTime));
MarkDirty();
mMetaHdr.mExpirationTime = aExpirationTime;
return NS_OK;
}
nsresult
CacheFileMetadata::GetExpirationTime(uint32_t *_retval)
{
*_retval = mMetaHdr.mExpirationTime;
return NS_OK;
}
nsresult
CacheFileMetadata::SetLastModified(uint32_t aLastModified)
{
LOG(("CacheFileMetadata::SetLastModified() [this=%p, lastModified=%d]",
this, aLastModified));
MarkDirty();
mMetaHdr.mLastModified = aLastModified;
return NS_OK;
}
nsresult
CacheFileMetadata::GetLastModified(uint32_t *_retval)
{
*_retval = mMetaHdr.mLastModified;
return NS_OK;
}
nsresult
CacheFileMetadata::GetLastFetched(uint32_t *_retval)
{
*_retval = mMetaHdr.mLastFetched;
return NS_OK;
}
nsresult
CacheFileMetadata::GetFetchCount(uint32_t *_retval)
{
*_retval = mMetaHdr.mFetchCount;
return NS_OK;
}
nsresult
CacheFileMetadata::OnFileOpened(CacheFileHandle *aHandle, nsresult aResult)
{
MOZ_CRASH("CacheFileMetadata::OnFileOpened should not be called!");
return NS_ERROR_UNEXPECTED;
}
nsresult
CacheFileMetadata::OnDataWritten(CacheFileHandle *aHandle, const char *aBuf,
nsresult aResult)
{
LOG(("CacheFileMetadata::OnDataWritten() [this=%p, handle=%p, result=0x%08x]",
this, aHandle, aResult));
MOZ_ASSERT(mListener);
MOZ_ASSERT(mWriteBuf);
free(mWriteBuf);
mWriteBuf = nullptr;
nsCOMPtr<CacheFileMetadataListener> listener;
mListener.swap(listener);
listener->OnMetadataWritten(aResult);
DoMemoryReport(MemoryUsage());
return NS_OK;
}
nsresult
CacheFileMetadata::OnDataRead(CacheFileHandle *aHandle, char *aBuf,
nsresult aResult)
{
LOG(("CacheFileMetadata::OnDataRead() [this=%p, handle=%p, result=0x%08x]",
this, aHandle, aResult));
MOZ_ASSERT(mListener);
nsresult rv;
nsCOMPtr<CacheFileMetadataListener> listener;
if (NS_FAILED(aResult)) {
LOG(("CacheFileMetadata::OnDataRead() - CacheFileIOManager::Read() failed, "
"creating empty metadata. [this=%p, rv=0x%08x]", this, aResult));
InitEmptyMetadata();
mListener.swap(listener);
listener->OnMetadataRead(NS_OK);
return NS_OK;
}
// check whether we have read all necessary data
uint32_t realOffset = PR_ntohl(*(reinterpret_cast<uint32_t *>(
mBuf + mBufSize - sizeof(uint32_t))));
int64_t size = mHandle->FileSize();
MOZ_ASSERT(size != -1);
if (realOffset >= size) {
LOG(("CacheFileMetadata::OnDataRead() - Invalid realOffset, creating empty "
"metadata. [this=%p, realOffset=%d, size=%lld]", this, realOffset,
size));
InitEmptyMetadata();
mListener.swap(listener);
listener->OnMetadataRead(NS_OK);
return NS_OK;
}
uint32_t usedOffset = size - mBufSize;
if (realOffset < usedOffset) {
uint32_t missing = usedOffset - realOffset;
// we need to read more data
mBuf = static_cast<char *>(moz_xrealloc(mBuf, mBufSize + missing));
memmove(mBuf + missing, mBuf, mBufSize);
mBufSize += missing;
DoMemoryReport(MemoryUsage());
LOG(("CacheFileMetadata::OnDataRead() - We need to read %d more bytes to "
"have full metadata. [this=%p]", missing, this));
rv = CacheFileIOManager::Read(mHandle, realOffset, mBuf, missing, this);
if (NS_FAILED(rv)) {
LOG(("CacheFileMetadata::OnDataRead() - CacheFileIOManager::Read() failed"
" synchronously, creating empty metadata. [this=%p, rv=0x%08x]",
this, rv));
InitEmptyMetadata();
mListener.swap(listener);
listener->OnMetadataRead(rv);
return NS_OK;
}
return NS_OK;
}
// We have all data according to offset information at the end of the entry.
// Try to parse it.
rv = ParseMetadata(realOffset, realOffset - usedOffset);
if (NS_FAILED(rv)) {
LOG(("CacheFileMetadata::OnDataRead() - Error parsing metadata, creating "
"empty metadata. [this=%p]", this));
InitEmptyMetadata();
}
mListener.swap(listener);
listener->OnMetadataRead(NS_OK);
return NS_OK;
}
nsresult
CacheFileMetadata::OnFileDoomed(CacheFileHandle *aHandle, nsresult aResult)
{
MOZ_CRASH("CacheFileMetadata::OnFileDoomed should not be called!");
return NS_ERROR_UNEXPECTED;
}
nsresult
CacheFileMetadata::OnEOFSet(CacheFileHandle *aHandle, nsresult aResult)
{
MOZ_CRASH("CacheFileMetadata::OnEOFSet should not be called!");
return NS_ERROR_UNEXPECTED;
}
void
CacheFileMetadata::InitEmptyMetadata()
{
if (mBuf) {
free(mBuf);
mBuf = nullptr;
mBufSize = 0;
}
mOffset = 0;
mMetaHdr.mFetchCount = 1;
mMetaHdr.mExpirationTime = NO_EXPIRATION_TIME;
mMetaHdr.mKeySize = mKey.Length();
DoMemoryReport(MemoryUsage());
}
nsresult
CacheFileMetadata::ParseMetadata(uint32_t aMetaOffset, uint32_t aBufOffset)
{
LOG(("CacheFileMetadata::ParseMetadata() [this=%p, metaOffset=%d, "
"bufOffset=%d]", this, aMetaOffset, aBufOffset));
nsresult rv;
uint32_t metaposOffset = mBufSize - sizeof(uint32_t);
uint32_t hashesOffset = aBufOffset + sizeof(uint32_t);
uint32_t hashCount = aMetaOffset / kChunkSize;
if (aMetaOffset % kChunkSize)
hashCount++;
uint32_t hashesLen = hashCount * sizeof(CacheHashUtils::Hash16_t);
uint32_t hdrOffset = hashesOffset + hashesLen;
uint32_t keyOffset = hdrOffset + sizeof(CacheFileMetadataHeader);
LOG(("CacheFileMetadata::ParseMetadata() [this=%p]\n metaposOffset=%d\n "
"hashesOffset=%d\n hashCount=%d\n hashesLen=%d\n hdfOffset=%d\n "
"keyOffset=%d\n", this, metaposOffset, hashesOffset, hashCount,
hashesLen,hdrOffset, keyOffset));
if (keyOffset > metaposOffset) {
LOG(("CacheFileMetadata::ParseMetadata() - Wrong keyOffset! [this=%p]",
this));
return NS_ERROR_FILE_CORRUPTED;
}
uint32_t elementsOffset = reinterpret_cast<CacheFileMetadataHeader *>(
mBuf + hdrOffset)->mKeySize + keyOffset + 1;
if (elementsOffset > metaposOffset) {
LOG(("CacheFileMetadata::ParseMetadata() - Wrong elementsOffset %d "
"[this=%p]", elementsOffset, this));
return NS_ERROR_FILE_CORRUPTED;
}
// check that key ends with \0
if (mBuf[elementsOffset - 1] != 0) {
LOG(("CacheFileMetadata::ParseMetadata() - Elements not null terminated. "
"[this=%p]", this));
return NS_ERROR_FILE_CORRUPTED;
}
if (!mKeyIsHash) {
uint32_t keySize = reinterpret_cast<CacheFileMetadataHeader *>(
mBuf + hdrOffset)->mKeySize;
if (keySize != mKey.Length()) {
LOG(("CacheFileMetadata::ParseMetadata() - Key collision (1), key=%s [this=%p]",
nsCString(mBuf + keyOffset, keySize).get(), this));
return NS_ERROR_FILE_CORRUPTED;
}
if (memcmp(mKey.get(), mBuf + keyOffset, mKey.Length()) != 0) {
LOG(("CacheFileMetadata::ParseMetadata() - Key collision (2), key=%s [this=%p]",
nsCString(mBuf + keyOffset, keySize).get(), this));
return NS_ERROR_FILE_CORRUPTED;
}
}
// check metadata hash (data from hashesOffset to metaposOffset)
CacheHashUtils::Hash32_t hash;
hash = CacheHashUtils::Hash(mBuf + hashesOffset,
metaposOffset - hashesOffset);
if (hash != PR_ntohl(*(reinterpret_cast<uint32_t *>(mBuf + aBufOffset)))) {
LOG(("CacheFileMetadata::ParseMetadata() - Metadata hash mismatch! Hash of "
"the metadata is %x, hash in file is %x [this=%p]", hash,
PR_ntohl(*(reinterpret_cast<uint32_t *>(mBuf + aBufOffset))), this));
return NS_ERROR_FILE_CORRUPTED;
}
// check elements
rv = CheckElements(mBuf + elementsOffset, metaposOffset - elementsOffset);
if (NS_FAILED(rv))
return rv;
mHashArraySize = hashesLen;
mHashCount = hashCount;
if (mHashArraySize) {
mHashArray = static_cast<CacheHashUtils::Hash16_t *>(
moz_xmalloc(mHashArraySize));
memcpy(mHashArray, mBuf + hashesOffset, mHashArraySize);
}
memcpy(&mMetaHdr, mBuf + hdrOffset, sizeof(CacheFileMetadataHeader));
mMetaHdr.mFetchCount++;
MarkDirty();
mElementsSize = metaposOffset - elementsOffset;
memmove(mBuf, mBuf + elementsOffset, mElementsSize);
mOffset = aMetaOffset;
// TODO: shrink memory if buffer is too big
DoMemoryReport(MemoryUsage());
return NS_OK;
}
nsresult
CacheFileMetadata::CheckElements(const char *aBuf, uint32_t aSize)
{
if (aSize) {
// Check if the metadata ends with a zero byte.
if (aBuf[aSize - 1] != 0) {
NS_ERROR("Metadata elements are not null terminated");
LOG(("CacheFileMetadata::CheckElements() - Elements are not null "
"terminated. [this=%p]", this));
return NS_ERROR_FILE_CORRUPTED;
}
// Check that there are an even number of zero bytes
// to match the pattern { key \0 value \0 }
bool odd = false;
for (uint32_t i = 0; i < aSize; i++) {
if (aBuf[i] == 0)
odd = !odd;
}
if (odd) {
NS_ERROR("Metadata elements are malformed");
LOG(("CacheFileMetadata::CheckElements() - Elements are malformed. "
"[this=%p]", this));
return NS_ERROR_FILE_CORRUPTED;
}
}
return NS_OK;
}
void
CacheFileMetadata::EnsureBuffer(uint32_t aSize)
{
if (mBufSize < aSize) {
mBufSize = aSize;
mBuf = static_cast<char *>(moz_xrealloc(mBuf, mBufSize));
}
DoMemoryReport(MemoryUsage());
}
} // net
} // mozilla