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UserspaceEmulator: Replace intersecting ranges if MAP_FIXED is specified

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This commit changes UserspaceEmulator to match the behavior that the
kernel has since ce1bf37.
This commit is contained in:
Daniel Bertalan 2021-12-22 11:27:57 +01:00 • committed by Andreas Kling
parent 9eb08bdb0f
commit 143dbba562
1 changed files with 4 additions and 2 deletions
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6
Userland/DevTools/UserspaceEmulator/Emulator_syscalls.cpp
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@ -874,9 +874,11 @@ u32 Emulator::virt$mmap(u32 params_addr)
if (params.flags & MAP_RANDOMIZED) {
result = m_range_allocator.allocate_randomized(requested_size, params.alignment);
} else if (params.flags & MAP_FIXED) {
if (params.addr)
if (params.addr) {
// If MAP_FIXED is specified, existing mappings that intersect the requested range are removed.
virt$munmap(params.addr, requested_size);
result = m_range_allocator.allocate_specific(VirtualAddress { params.addr }, requested_size);
else {
} else {
// mmap(nullptr, …, MAP_FIXED) is technically okay, but tends to be a bug.
// Therefore, refuse to be helpful.
reportln("\n=={}== \033[31;1mTried to mmap at nullptr with MAP_FIXED.\033[0m, {:#x} bytes.", getpid(), params.size);