Mirrors_Framework/PX4-Autopilot
1
0
Fork 0
mirror of https://github.com/PX4/PX4-Autopilot.git synced 2026-05-09 22:08:56 +08:00
Code Issues Actions 3 Packages Projects Releases Wiki Activity

fix(windows-shim): reject mmap MAP_FIXED with ENOTSUP

Browse Source 
The Windows mmap shim cannot honour MAP_FIXED safely: VirtualAlloc /
MapViewOfFile cannot replace existing mappings at a caller-supplied
address, so accepting the flag would silently fall through to a
non-fixed allocation and the caller would get back an address that
does not match the one it asked for. The shim header documents this
contract; the implementation now matches it by returning MAP_FAILED
with errno set to ENOTSUP when MAP_FIXED is requested.

Fixes the MAP_FIXED expectation in the mmap unit tests, which now
get the expected MAP_FAILED return instead of a surprise fallback
mapping at a different address.

Signed-off-by: Nuno Marques <n.marques21@hotmail.com>
This commit is contained in:
Nuno Marques
2026-05-07 18:04:49 -07:00
parent 62b6ed9689
commit cf34e41adb
1 changed files with 8 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
platforms/posix/src/px4/windows/posix/fs/mman.cpp
+8
View File
@@ -60,6 +60,14 @@ static DWORD mman_page_protect(int prot)
extern "C" void *mmap(void *, size_t length, int prot, int flags, int fd, off_t offset)
{
/* MAP_FIXED is rejected because the Windows backend (VirtualAlloc /
* MapViewOfFile) cannot safely replace existing mappings at a caller
* supplied address. The shim header documents this contract. */
if (flags & MAP_FIXED) {
errno = ENOTSUP;
return MAP_FAILED;
}
const bool anon = (flags & (MAP_ANON | MAP_ANONYMOUS)) != 0;
if (anon || fd < 0) {