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Separate snapshot storage holder and snap data allocations

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Previously, only one buffer was allocated to store each snapshot holder structure, the snapshot data and alternative snapshot data. This prevents tools like ASAN from detecting some invalid accesses, e.g. to the snapshot holder structure by underflowing the snapshot data pointer. Now three separate allocations are used instead. This hopefully helps debugging #2677.
This commit is contained in:
Robert Müller 2023-11-12 23:45:19 +01:00
parent 0c33be1692
commit efc451324d
1 changed files with 13 additions and 18 deletions
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31
src/engine/shared/snapshot.cpp
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@ -464,17 +464,14 @@ void CSnapshotStorage::Init()
void CSnapshotStorage::PurgeAll() void CSnapshotStorage::PurgeAll()
{ {
CHolder *pHolder = m_pFirst; while(m_pFirst)
while(pHolder)
{ {
CHolder *pNext = pHolder->m_pNext; CHolder *pNext = m_pFirst->m_pNext;
free(pHolder); free(m_pFirst->m_pSnap);
pHolder = pNext; free(m_pFirst->m_pAltSnap);
free(m_pFirst);
m_pFirst = pNext;
} }
// no more snapshots in storage
m_pFirst = nullptr;
m_pLast = nullptr; m_pLast = nullptr;
} }
@ -487,6 +484,8 @@ void CSnapshotStorage::PurgeUntil(int Tick)
CHolder *pNext = pHolder->m_pNext; CHolder *pNext = pHolder->m_pNext;
if(pHolder->m_Tick >= Tick) if(pHolder->m_Tick >= Tick)
return; // no more to remove return; // no more to remove
free(pHolder->m_pSnap);
free(pHolder->m_pAltSnap);
free(pHolder); free(pHolder);
// did we come to the end of the list? // did we come to the end of the list?
@ -495,7 +494,6 @@ void CSnapshotStorage::PurgeUntil(int Tick)
m_pFirst = pNext; m_pFirst = pNext;
pNext->m_pPrev = nullptr; pNext->m_pPrev = nullptr;
pHolder = pNext; pHolder = pNext;
} }
@ -509,20 +507,17 @@ void CSnapshotStorage::Add(int Tick, int64_t Tagtime, size_t DataSize, const voi
dbg_assert(DataSize <= (size_t)CSnapshot::MAX_SIZE, "Snapshot data size invalid"); dbg_assert(DataSize <= (size_t)CSnapshot::MAX_SIZE, "Snapshot data size invalid");
dbg_assert(AltDataSize <= (size_t)CSnapshot::MAX_SIZE, "Alt snapshot data size invalid"); dbg_assert(AltDataSize <= (size_t)CSnapshot::MAX_SIZE, "Alt snapshot data size invalid");
// allocate memory for holder + snapshot data CHolder *pHolder = static_cast<CHolder *>(malloc(sizeof(CHolder)));
const size_t TotalSize = sizeof(CHolder) + DataSize + AltDataSize;
CHolder *pHolder = (CHolder *)malloc(TotalSize);
// set data
pHolder->m_Tick = Tick; pHolder->m_Tick = Tick;
pHolder->m_Tagtime = Tagtime; pHolder->m_Tagtime = Tagtime;
pHolder->m_SnapSize = DataSize;
pHolder->m_pSnap = (CSnapshot *)(pHolder + 1); pHolder->m_pSnap = static_cast<CSnapshot *>(malloc(DataSize));
mem_copy(pHolder->m_pSnap, pData, DataSize); mem_copy(pHolder->m_pSnap, pData, DataSize);
pHolder->m_SnapSize = DataSize;
if(AltDataSize) // create alternative if wanted if(AltDataSize) // create alternative if wanted
{ {
pHolder->m_pAltSnap = (CSnapshot *)(((char *)pHolder->m_pSnap) + DataSize); pHolder->m_pAltSnap = static_cast<CSnapshot *>(malloc(AltDataSize));
mem_copy(pHolder->m_pAltSnap, pAltData, AltDataSize); mem_copy(pHolder->m_pAltSnap, pAltData, AltDataSize);
pHolder->m_AltSnapSize = AltDataSize; pHolder->m_AltSnapSize = AltDataSize;
} }