Instead of doing so in the constructor, let's do immediately after the
constructor, so we can safely pass a reference of a Device, so the
SysFSDeviceComponent constructor can use that object to identify whether
it's a block device or a character device.
This allows to us to not hold a device in SysFSDeviceComponent with a
RefPtr.
Also, we also call the before_removing method in both SlavePTY::unref
and File::unref, so because Device has that method being overrided, it
can ensure the device is removed always cleanly.
These files are not marked as block devices or character devices so they
are not meant to be used as device nodes. The filenames are formatted to
the pattern "major:minor", but a Userland program need to call the parse
these format and inspect the the major and minor numbers and create the
real device nodes in /dev.
Later on, it might be a good idea to ensure we don't create new
SysFSComponents on the heap for each Device, but rather generate
them only when required (and preferably to not create a SysFSComponent
at all if possible).
- Use KResultOr and TRY() to propagate errors
- Check for OOM errors
- Move allocation out of constructors
There's still a lot more to do here, as SysFS is still quite brittle
in the face of memory pressure.
Like with the ProcFS, description data can change at anytime, so it's
wise to ensure that when the userland reads from an Inode, data is
consistent unless the userland indicated it wants to refresh the data
(by seeking to offset 0, or re-attaching the Inode).
Otherwise, if the data changes in the middle of the reading, it can
cause silent corruption in output which can lead to random crashes.
Prior to this change, both uid_t and gid_t were typedef'ed to `u32`.
This made it easy to use them interchangeably. Let's not allow that.
This patch adds UserID and GroupID using the AK::DistinctNumeric
mechanism we've already been employing for pid_t/ProcessID.
The intention is to add dynamic mechanism for notifying the userspace
about hotplug events. Currently, the DMI (SMBIOS) blobs and ACPI tables
are exposed in the new filesystem.
