On Fri, 31 May 2024 at 22:21, Octavian Purdila <ta...@google.com> wrote:
>
> Add path option to the pty char backend which will create a symbolic
> link to the given path that points to the allocated PTY.
>
> Based on patch from Paulo Neves:
>
> https://patchew.org/QEMU/1548509635-15776-1-git-send-email-ptsne...@gmail.com/
>
> Tested with the following invocations that the link is created and
> removed when qemu stops:
>
> qemu-system-x86_64 -nodefaults -mon chardev=compat_monitor \
> -chardev pty,path=test,id=compat_monitor0
>
> qemu-system-x86_64 -nodefaults -monitor pty:test
>
> Also tested that when a link path is not passed invocations still work, e.g.:
>
> qemu-system-x86_64 -monitor pty
Could we have some justification here for why the new
functionality is useful, please? (e.g. what new use cases
it permits).
> --- a/qapi/char.json
> +++ b/qapi/char.json
> @@ -509,7 +509,7 @@
> ##
> # @ChardevHostdevWrapper:
> #
> -# @data: Configuration info for device and pipe chardevs
> +# @data: Configuration info for device, pty and pipe chardevs
> #
> # Since: 1.4
> ##
> @@ -650,7 +650,7 @@
> 'pipe': 'ChardevHostdevWrapper',
> 'socket': 'ChardevSocketWrapper',
> 'udp': 'ChardevUdpWrapper',
> - 'pty': 'ChardevCommonWrapper',
> + 'pty': 'ChardevHostdevWrapper',
> 'null': 'ChardevCommonWrapper',
> 'mux': 'ChardevMuxWrapper',
> 'msmouse': 'ChardevCommonWrapper',
Does this break QAPI compatibility?
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 8ca7f34ef0..5eec194242 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -3569,7 +3569,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
> "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
> "-chardev
> serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
> #else
> - "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
> + "-chardev
> pty,id=id[,path=path][,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
> "-chardev
> stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
> #endif
> #ifdef CONFIG_BRLAPI
> @@ -3808,12 +3808,16 @@ The available backends are:
>
> ``path`` specifies the name of the serial device to open.
>
> -``-chardev pty,id=id``
> +``-chardev pty,id=id[,path=path]``
> Create a new pseudo-terminal on the host and connect to it. ``pty``
> does not take any options.
We just added an option, so we should delete the line saying
that it doesn't take any options :-)
>
> ``pty`` is not available on Windows hosts.
>
> + ``path`` specifies the symbolic link path to be created that
> + points to the pty device.
I think we could usefully make this a little less terse. Perhaps
If ``path`` is specified, QEMU will create a symbolic link at
that location which points to the new PTY device.
?
thanks
-- PMM
