Hello! As mentioned in [0], glib is in need of a native Hurd backend for GLocalFileMonitor. This is what this patch aims to implement. It is *nowhere* near complete yet, but there should hopefully be already enough things in place to start gathering feedback, both from the Hurd and glib sides.
[0]: https://lists.debian.org/debian-hurd/2022/03/msg00015.html A brief overview of the patch: * gio/hurd is a new directory containing the GHurdFileMonitor implementation, just like gio/inotify contains GInotifyFileMonitor and gio/kqueue contains GKqueueFileMonitor * Meson is hooked up to invoke MIG to generate fs_notifyServer.c and fs_notify_S.h; it would appear I've managed to do this without having to hardcode the full path to /usr/include/i386-gnu/hurd/fs_notify.defs * There's a separate, implicitly spawned thread (GThread) that waits on incoming messages (in mach_msg_server) * We're not supposed to use libports, so there's an explicit port set and a hashtable. Fortunately glib already has a hashtable implementation (so we don't need hurd/ihash) as well as refcounting for GObject-s. Is it fine that I only insert the port into the hashtable if mach_port_set_protected_payload () fails? In other words, is it legal for mach_msg not to pass the protected payload if one has been set for the port? * We receive {dir,file}_changed_type and attempt to map the it to GFileMonitorEvent. The mapping is kind of coarse for now, maybe things could be improved here. * There's something fishy that glibc expects wrt basename/dirname/filename, for instance if you watch a single file, it still expects you to pass the file basename into g_file_monitor_source_handle_event (), and will ignore any events with a non-matching basename, as if you were actually watching the parent directory and not that one file. This is probably related to inotify semantics or something, I have not looked into this yet. I'd have to look into what exactly glib expects and how to emulate that. * Error handling with abort () is all over the place. I don't know how it's supposed to work -- while g_file_monitor () accepts a GError **error argument, g_hurd_file_monitor_start () does not. It's unclear where it's supposed to propagate errors to. But despite all the incompleteness and deficiencies, the patch seems to work somewhat. glib recognizes GHurdFileMonitor as a legitimate type, it gets picked up as the preferred backend for GLocalFileMonitor, it actually receives a call to g_hurd_file_monitor_start (), the port manipulation stuff works, we do get the file_changed message from the translator, and the ::changed signal does get emitted indeed. Feedback is very welcome! Sergey Sergey Bugaev (1): Very WIP: Add GHurdFileMonitor gio/giomodule.c | 4 + gio/hurd/fs_notify.defs | 9 ++ gio/hurd/fs_notify.h | 10 ++ gio/hurd/ghurdfilemonitor.c | 269 ++++++++++++++++++++++++++++++++++++ gio/hurd/ghurdfilemonitor.h | 43 ++++++ gio/hurd/meson.build | 20 +++ gio/meson.build | 5 + 7 files changed, 360 insertions(+) create mode 100644 gio/hurd/fs_notify.defs create mode 100644 gio/hurd/fs_notify.h create mode 100644 gio/hurd/ghurdfilemonitor.c create mode 100644 gio/hurd/ghurdfilemonitor.h create mode 100644 gio/hurd/meson.build -- 2.38.1
