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UserspaceEmulator: Mark mmap regions as malloc blocks when mallocing

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We don't have to be clever at all to figure out which MmapRegions are
malloc blocks, we can just mark the containing region as such when
the emulated process performs a malloc! :^)
This commit is contained in:
Andreas Kling 2020-08-01 09:13:45 +02:00
parent 5de7bae383
commit 030edbd513
3 changed files with 7 additions and 8 deletions
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4
DevTools/UserspaceEmulator/MallocTracer.cpp
View file

@ -44,6 +44,10 @@ void MallocTracer::target_did_malloc(Badge<SoftCPU>, FlatPtr address, size_t siz
ASSERT(region);
ASSERT(region->is_mmap());
auto& mmap_region = static_cast<MmapRegion&>(*region);
// Mark the containing mmap region as a malloc block!
mmap_region.set_malloc(true);
auto* shadow_bits = mmap_region.shadow_data() + address - mmap_region.base();
memset(shadow_bits, 0, size);

7
DevTools/UserspaceEmulator/MmapRegion.cpp
View file

@ -65,13 +65,6 @@ MmapRegion::~MmapRegion()
free(m_data);
}
bool MmapRegion::is_malloc_block() const
{
// FIXME: This is obviously incomplete!
// We should somehow know which mmap regions are malloc blocks.
return !m_file_backed;
}
ValueWithShadow<u8> MmapRegion::read8(FlatPtr offset)
{
if (!is_readable()) {

4
DevTools/UserspaceEmulator/MmapRegion.h
View file

@ -52,7 +52,8 @@ public:
bool is_writable() const { return m_prot & PROT_WRITE; }
bool is_executable() const { return m_prot & PROT_EXEC; }
bool is_malloc_block() const;
bool is_malloc_block() const { return m_malloc; }
void set_malloc(bool b) { m_malloc = b; }
private:
MmapRegion(u32 base, u32 size, int prot);
@ -62,6 +63,7 @@ private:
u8* m_shadow_data { nullptr };
int m_prot { 0 };
bool m_file_backed { false };
bool m_malloc { false };
};
}