[Qemu-devel] [PATCH] chardev: Allow for pty path passing.

[Paulo Neves]

Hello all.
I am trying to get qemu to spawn a pty terminal in a location
which I control without needing to retrieve information of the PTY device
a-posteriori from qemu. To this end i inspired myself in the functionality
of socat, which allows PTY terminals to be spawned in a location
specified by a command line argument. The way socat does is a
bit cheating: It requests the PTY terminal the same way that qemu
does, through openpty, and creates a symlink between the path
specified by the user and the kernel given virtual terminal device.

In the following patch i was able to implement this functionality
successfully and it works as intended. The problem is that for some
reason when I send Ctrl-a-x through the pty the finalize method of
the pty char dev does not get called, thus not removing the symlink.
The finalize only is called when there is an error in the creation of
the symlink like for example when the symlink already exists.

This leads to a dangling symlink when qemu closes and the PTY is released.
Is there a better way to guarantee that my unlink of the symlink is
called when qemu closes? Am i not familiar with qemu code development
so if i am doing something terrible please let me know.