[winstrex]

What

On Windows, sceKernelOpen with O_DIRECTORY fails with 0x80020002 (ENOENT) on an existing directory when the resolved host path ends in a separator. That covers the guest root /, ., <dir>/ and <dir>/... Only <dir> without a trailing separator opens.

Found with The Pathless (PPSA01825). At boot, Unreal calls sceKernelOpen("/app0/..", O_DIRECTORY) to list the parent of the content root. On Windows the call returned ENOENT and getdents was never reached:

[src/Open.cpp sceKernelOpen] path=/app0/.. flags=0x20000 nativeFlags=0x8000 mode=0555
-> 0x80020002

Cause: in OpenNative (core/libs/prx/libkernel/File/src/Open.cpp), the CRT _wopen fails on a path ending in \ with ENOENT, and the fallback to File::OpenDirectoryDescriptor only runs when errno != ENOENT. A directory whose host path ends in a separator never reaches it.

Fix: when the host path has no filename, the fallback runs regardless of the errno. Trailing separators are stripped with the same loop sceKernelMkdir uses since #2819 (while (!path.has_filename() && path.has_relative_path()) path = path.parent_path()), so a host drive root such as C:\ is kept as is. The directory descriptor is then opened on the stripped path. A missing path without a trailing separator still returns ENOENT without an extra stat, and the EEXIST/EISDIR checks are unchanged. Linux is unaffected because open(2) accepts a trailing slash on a directory.

This follows the earlier trailing-separator fixes in libkernel: #2743/#2819 (sceKernelMkdir) and #2300 (sceKernelStat).

Tested

Windows 11, WinLibs GCC 15.2.

• guest_filesystem now opens /, ., <dir>/ and <dir>/.. with O_DIRECTORY and calls sceKernelGetdents until it returns 0. Without the change in Open.cpp the test fails at the first open (guest errno 2); with it, it passes.
• ctest -R "guest_|file|kernel": 346 tests passed.
• Linux and Windows: full CI on my fork, green: https://github.com/winstrex/AnyPS5/actions/runs/38255891314
• The Pathless (PPSA01825, own dump), Windows: open("/app0/..", O_DIRECTORY) now returns a descriptor and the listing completes (getdents returns 88 bytes, then 0). The title still stops right after it, in the same place as before: Project file not found: ../../../Pathless/Pathless.uproject, then PS5 Out of Memory / LowLevelFatalError ... Ran out of memory allocating 5565054976 bytes. That stop has a different cause and is not addressed here: it is the PlayGo chunk enumeration described for Sifu on Sifu (PPSA03001): RenderThread faults popping a free list whose head reads 0xFFFFFFFFFFFFFFFF #3209 and fix(libScePlayGo): accept chunk ids when the dump has no chunk definitions #3238 (the dump has no chunk table, the title queries ever-increasing chunk ids, and the request size is the same).

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed in TechnicalDebt
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• Unblocks: none (PPSA01825 gets past this open but stops right after it, see Tested)
• AI-assisted: yes

[xXPBSXx]

Windows test: head a47178b86 merged onto current main d592d54e1 (clean merge, no conflicts). Windows 10, MinGW GCC (WinLibs), Ninja Release, -j2: full build 0 errors; ctest with the filter guest_filesystem: guest_filesystem passed (1 test(s), 0 failed); python tools/check_conventions.py --base upstream/main passed. I did not run the new tests against main without the change.

AI-assisted (Claude Code).