RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-18 09:05:07 +00:00
Code Issues Activity Actions

Kernel: Replace intersecting ranges in mmap when MAP_FIXED is specified

Browse source 
This behavior is mandated by POSIX and is used by software like Wine
after reserving large chunks of the address range.
This commit is contained in:
Daniel Bertalan 2021-12-19 01:01:11 +01:00 • committed by Brian Gianforcaro
parent fd3be7ffcc
commit ce1bf3724e
1 changed files with 5 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

5
Kernel/Syscalls/mmap.cpp
View file

@ -189,11 +189,16 @@ ErrorOr<FlatPtr> Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> use
if (map_randomized) { if (map_randomized) {
return address_space().page_directory().range_allocator().try_allocate_randomized(Memory::page_round_up(size), alignment); return address_space().page_directory().range_allocator().try_allocate_randomized(Memory::page_round_up(size), alignment);
} }
auto range = address_space().try_allocate_range(VirtualAddress(addr), size, alignment); auto range = address_space().try_allocate_range(VirtualAddress(addr), size, alignment);
if (range.is_error()) { if (range.is_error()) {
if (addr && !map_fixed) { if (addr && !map_fixed) {
// If there's an address but MAP_FIXED wasn't specified, the address is just a hint. // If there's an address but MAP_FIXED wasn't specified, the address is just a hint.
range = address_space().try_allocate_range({}, size, alignment); range = address_space().try_allocate_range({}, size, alignment);
} else if (map_fixed) {
// If MAP_FIXED is specified, existing mappings that intersect the requested range are removed.
TRY(address_space().unmap_mmap_range(VirtualAddress(addr), size));
range = address_space().try_allocate_range(VirtualAddress(addr), size, alignment);
} }
} }
return range; return range;