Cloudberry Kingdom (PPSA23827, #3177) registers its first kevent change
as a file watch: ident 3, EVFILT_VNODE, flags 0x25
(EV_ADD|EV_ENABLE|EV_CLEAR), fflags 0x37
(NOTE_DELETE|WRITE|EXTEND|LINK|RENAME). Palworld's Discord module
(PPSA23126, #2648) imports sceKernelAddFileEvent and
sceKernelDeleteFileEvent, which no library exported.
EVFILT_VNODE watches the host file or directory behind the descriptor
and turns host changes into FreeBSD 11 vnode hints, added whole when
they share a bit with the requested fflags as filt_vfsvnode does
(sys/kern/vfs_subr.c, release/11.0.1 34bd3475): a growing write is
NOTE_WRITE|NOTE_EXTEND, a shrinking truncate or an attribute change
NOTE_ATTRIB, a link count change NOTE_LINK or NOTE_DELETE, a pending
delete NOTE_DELETE, a new path NOTE_RENAME, and in a directory a new,
removed or renamed entry NOTE_WRITE (with NOTE_LINK for a subdirectory,
as vop_mkdir_post/vop_rmdir_post). Windows uses FindFirstChangeNotification
on the parent directory (and the watched directory) and compares handle
snapshots every 50 ms, since a write through an open handle is not
reported until it is flushed or closed (measured); Linux uses inotify.
Closing the descriptor, deleting the event or the queue stops the
watcher.
sceKernelAddFileEvent(eq, fd, watch, udata) and
sceKernelDeleteFileEvent(eq, fd) take the OpenOrbis 0a1aaf9d
(libkernel.h:35,109) and SharpProspero 5dfdb4b0 (KernelEqueue.cs:164,168)
signatures; NIDs cG3t15OK4Ow and UmXngHKB6is confirmed with
tools/nid_names.py. The watch bits are the fflags and the event is added
with EV_CLEAR, which is not confirmed on a title.
Throws: NOTE_REVOKE, NOTE_OPEN, NOTE_CLOSE, NOTE_CLOSE_WRITE, NOTE_READ
and unknown bits, NOTE_EXTEND on a directory on Windows (a move from
another directory cannot be told from a creation) and descriptors that
are not files, directories, pipes or sockets (pipes, sockets and kqueues
fail with EINVAL as in FreeBSD). Recorded in TechnicalDebt.
guest_kqueue adds a vnode watch that sees a write to a temporary file
with Cloudberry's flags, fflags filtering, a re-registration, the sce
pair on an equeue, EINVAL for sockets, pipes and the kqueue itself, the
close of a watched descriptor and a directory watch.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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