[Qemu-devel] [PATCH 0/6] qga: add support for re-opening channel on error

[Michael Roth]

The following patches are also available at:
  https://github.com/mdroth/qemu/commits/qga-retry-path

This series adds a --retry-path option to qemu-ga to allow the agent
to periodically re-attempt opening a channel if the channel is not
yet present (e.g. qemu-ga is installed before virtio-serial drivers)
or if the channel encounters an error that might be recoverable (e.g.
the channel is hot unplugged/plugged).

This functionality is already possible via init systems like systemd (and
is already set up that way on Fedora), but we implement this option
to handle other OSs like Windows (where this was originally reported as
a problem).

PATCH 1-3 implement various refactorings that more clearly encapsulate
the agent's lifecycle into:

 a) config parsing (via main())
 b) initializing the agent (via initialize_agent())
 c) starting the agent (via run_agent())
 d) stopping the agent (via stop_agent())
 e) cleaning up the agent (via cleanup_agent())
 f) cleaning up the config (via main())

PATCH 4 implements the actual --retry-path option, which simply wraps
run_agent() in a continuous loop until the agent is explicitly told
to exit.

 qga/channel-win32.c       |   3 +-
 qga/installer/qemu-ga.wxs |   2 +-
 qga/main.c                | 205 
++++++++++++++++++++++++++++++++++++++++++++++++------------------------
 3 files changed, 141 insertions(+), 69 deletions(-)