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UserspaceEmulator: Support munmap/mprotect with partial mappings

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Fixes #5663.
This commit is contained in:
Ben Wiederhake 2021-03-08 19:20:09 +01:00 • committed by Andreas Kling
parent 45443f24ec
commit 1e857de263
3 changed files with 70 additions and 17 deletions
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63
Userland/DevTools/UserspaceEmulator/Emulator.cpp
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@ -980,14 +980,35 @@ int Emulator::virt$pipe(FlatPtr vm_pipefd, int flags)
return rc;
}
u32 Emulator::virt$munmap(FlatPtr address, u32 size)
static void round_to_page_size(FlatPtr& address, size_t& size)
{
auto* region = mmu().find_region({ 0x23, address });
VERIFY(region);
if (region->size() != round_up_to_power_of_two(size, PAGE_SIZE))
TODO();
m_range_allocator.deallocate(region->range());
mmu().remove_region(*region);
auto new_end = round_up_to_power_of_two(address + size, PAGE_SIZE);
address &= ~(PAGE_SIZE - 1);
size = new_end - address;
}
u32 Emulator::virt$munmap(FlatPtr address, size_t size)
{
round_to_page_size(address, size);
Vector<Region*, 4> marked_for_deletion;
bool has_non_mmap_region = false;
mmu().for_regions_in({ 0x23, address }, size, [&](Region* region) {
if (region) {
if (!is<MmapRegion>(*region)) {
has_non_mmap_region = true;
return IterationDecision::Break;
}
marked_for_deletion.append(region);
}
return IterationDecision::Continue;
});
if (has_non_mmap_region)
return -EINVAL;
for (Region* region : marked_for_deletion) {
m_range_allocator.deallocate(region->range());
mmu().remove_region(*region);
}
return 0;
}
@ -1037,6 +1058,7 @@ FlatPtr Emulator::virt$mremap(FlatPtr params_addr)
Syscall::SC_mremap_params params;
mmu().copy_from_vm(&params, params_addr, sizeof(params));
// FIXME: Support regions that have been split in the past (e.g. due to mprotect or munmap).
if (auto* region = mmu().find_region({ m_cpu.ds(), params.old_address })) {
if (!is<MmapRegion>(*region))
return -EINVAL;
@ -1086,15 +1108,24 @@ u32 Emulator::virt$unveil(u32)
u32 Emulator::virt$mprotect(FlatPtr base, size_t size, int prot)
{
if (auto* region = mmu().find_region({ m_cpu.ds(), base })) {
if (!is<MmapRegion>(*region))
return -EINVAL;
VERIFY(region->size() == size);
auto& mmap_region = *(MmapRegion*)region;
mmap_region.set_prot(prot);
return 0;
}
return -EINVAL;
round_to_page_size(base, size);
bool has_non_mmaped_region = false;
mmu().for_regions_in({ 0x23, base }, size, [&](Region* region) {
if (region) {
if (!is<MmapRegion>(*region)) {
has_non_mmaped_region = true;
return IterationDecision::Break;
}
auto& mmap_region = *(MmapRegion*)region;
mmap_region.set_prot(prot);
}
return IterationDecision::Continue;
});
if (has_non_mmaped_region)
return -EINVAL;
return 0;
}
u32 Emulator::virt$madvise(FlatPtr, size_t, int)