This adds a win32 channel implementation that makes qemu-ga functional
on Windows using virtio-serial (unix-listen/isa-serial not currently
implemented). Unlike with the posix implementation, we do not use
GIOChannel for the following reasons:
- glib calls stat() on an fd to check whether S_IFCHR is set, which is
the case for virtio-serial on win32. Because of that, a one-time
check to determine whether the channel is readable is done by making
a call to PeekConsoleInput(), which reports the underlying handle is
not a valid console handle, and thus we can never read from the
channel.
- if one goes as far as to "trick" glib into thinking it is a normal
file descripter, the buffering is done in such a way that data
written to the output stream will subsequently result in that same
data being read back as if it were input, causing an error loop.
furthermore, a forced flush of the channel only moves the data into a
secondary buffer managed by glib, so there's no way to prevent output
from getting read back as input.
The implementation here ties into the glib main loop by implementing a
custom GSource that continually submits asynchronous/overlapped I/O to
fill an GAChannel-managed read buffer, and tells glib to poll the
corresponding event handle for a completion whenever there is no
data/RPC in the read buffer to notify the main application about.
Various stubs and #ifdefs to compile for Windows using mingw
cross-build. Still has 1 linker error due to a dependency on the
forthcoming win32 versions of the GAChannel/transport class.
Many of the current RPC implementations are very much POSIX-specific
and require complete re-writes for Windows. There are however a small
set of core guest agent commands that are common to both, and other
commands such as guest-file-* which *may* be portable. So we introduce
commands.c for the latter, and will rename guest-agent-commands.c to
commands-posix.c in a future commit. Windows implementations will go in
commands-win32.c, eventually.
This is mostly in preparation for the win32 port, which won't use
GIO channels for reasons that will be made clearer later. Here the
GAChannel class is just a loose wrapper around GIOChannel
calls/callbacks, but we also roll in the logic/configuration for
various channel types and managing unix socket connections, which makes
the abstraction much more complete and further aids in the win32 port
since isa-serial/unix-listen will not be supported initially.
There's also a bit of refactoring in the main logic to consolidate the
exit paths so we can do common cleanup for things like pid files, which
weren't always cleaned up previously.
Not that there is blacklisting functionality we can no longer infer
the agent's capabilities via version. This patch extends the current
guest-info RPC to also return a list of dictionaries containing the name
of each supported RPC, along with a boolean indicating whether or not
the command has been disabled by a guest administrator/distro.
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This is the actual guest daemon, it listens for requests over a
virtio-serial/isa-serial/unix socket channel and routes them through
to dispatch routines, and writes the results back to the channel in
a manner similar to QMP.
A shorthand invocation:
qemu-ga -d
Is equivalent to:
qemu-ga -m virtio-serial -p /dev/virtio-ports/org.qemu.guest_agent.0 \
-f /var/run/qemu-ga.pid -d
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@gmail.com>
