0ct0pu5/ladybird
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 2

Kernel: Reject writable shared file mappings

Browse source 
We have no way of writing changes to memory-mapped files back to disk,
and software relying on this functionality for output would fail
miserably. Let's just return ENOTSUP instead to allow callers to fall
back to standard file IO instead of silently discarding writes.

This makes the LLD port work, which uses memory-mapped files to write
its output by default.
This commit is contained in:
Daniel Bertalan 2021-11-16 22:49:25 +01:00 • committed by Andreas Kling
parent a1d5849e67
commit 304c03f457
Notes: sideshowbarker 2024-07-18 01:03:55 +09:00
1 changed files with 5 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
Kernel/FileSystem/InodeFile.cpp
View file

@ -83,6 +83,11 @@ ErrorOr<void> InodeFile::ioctl(OpenFileDescription& description, unsigned reques
ErrorOr<Memory::Region*> InodeFile::mmap(Process& process, OpenFileDescription& description, Memory::VirtualRange const& range, u64 offset, int prot, bool shared)
{
// FIXME: Support writing changes made to shared file mappings back to disk.
// Some ports behave incorrectly if we silently discard writes to memory-mapped files, so let's not lie about what we can do.
if (shared && (prot & PROT_WRITE))
return ENOTSUP;
// FIXME: If PROT_EXEC, check that the underlying file system isn't mounted noexec.
RefPtr<Memory::InodeVMObject> vmobject;
if (shared)