Re: [Qemu-devel] [QAPI+QGA 3/3] QEMU Guest Agent (virtagent) v7

[Zhi Yong Wu]

On Sat, Jul 16, 2011 at 12:27 AM, Luiz Capitulino
<address@hidden> wrote:
> On Fri, 15 Jul 2011 09:15:18 +0800
> Zhi Yong Wu <address@hidden> wrote:
>
>> On Fri, Jul 15, 2011 at 4:00 AM, Michael Roth <address@hidden> wrote:
>> > This is Set 3/3 of the QAPI+QGA patchsets.
>> >
>> > These patches apply on top of qapi-backport-set2-v6, and can also be 
>> > obtained from:
>> > git://repo.or.cz/qemu/mdroth.git qapi-backport-set3-v7
>> >
>> > (Set1+2 are a backport of some of the QAPI-related work from Anthony's
>> > glib tree. The main goal is to get the basic code generation 
>> > infrastructure in
>> > place so that it can be used by the guest agent to implement a QMP-like 
>> > guest
>> > interface, and so that future work regarding the QMP conversion to QAPI 
>> > can be
>> > decoupled from the infrastructure bits. Set3 is the Qemu Guest Agent
>> > (virtagent), rebased on the new code QAPI code generation infrastructure. 
>> > This
>> > is the first user of QAPI, QMP will follow.)
>> > ___
>> >
>> > CHANGES SINCE V6:
>> >  - Made "/dev/virtio-ports/org.qemu.guest_agent.0" default device path for 
>> > agent
>> >  - Consolidated uneeded fcntl() calls into qemu_open()
>> >  - JSON/QMP parse errors now propagated to client
>> >  - Replaced non-assertion uses of g_error() with exit()
>> >  - Added guest-file-flush
>> >  - Removed limit on max read size for guest-file-read
>> >  - 'count' parameters to guest-file-read/guest-file-write are now optional 
>> > (default to 4KB and size of provided buffer, base64-decoded, respectively)
>> >  - Removed redundant 'file_' and 'shutdown_' prefixes from 
>> > guest-file-*/guest-shutdown commands, switched to "-" in place of "_" in 
>> > parameter names, renamed guest-file-read's "buf" param to "buf-b64" and 
>> > guest-file-write's "data_b64" param to "buf-b64" for consistency.
>> >  - guest-fsfreeze-freeze now returns error objects on error rather as part 
>> > of it's integer return values, and on error will unfreeze previously 
>> > frozen filesystems.
>> >  - GUEST_FSFREEZE_STATUS_INPROGRESS removed, GUEST_FSFREEZE_STATUS_ERROR 
>> > now serves the explicit purpose of noting a failure to find a previously 
>> > mounted filesytem/directory after initial freeze, or failure to unfreeze 1 
>> > or more filesystems.
>> >  - -c/--channel option to qemu-ga is now -m/--method
>> >
>> > CHANGES SINCE V5:
>> >  - switched to using qemu malloc/list functions where possible
>> >  - removed unused proxy_path field in struct GAState
>> >  - pid file now opened write-only, removed lockf() in favor of O_EXCL, 
>> > added SIGINT/SIGTERM signal handlers to handle cleanup
>> >  - cleaned up error-handling, switched to asserts where appropriate, 
>> > removed unecessary gotos and NULL checks for qemu_free()/qobject_decref()
>> >  - refactored send_payload() using helper functions
>> >  - fixed improper handling of pidfile fd==0
>> >  - changed guest-shutdown's "shutdown_mode" param to "mode"
>> >  - switched to using kernel-generated FDs for guest-file-open rather than 
>> > an autoincrement value
>> >  - add maximum chunk size of guest-file-read/guest-file-write
>> >  - added checks to avoid guest-file-write from writing data beyond the 
>> > provided data buffer
>> >  - made logging best-effort, removed handling of failures to log as errors
>> >  - guest-shutdown exec errors now logged to guest syslog, clarified 
>> > shutdown's asynchronous, no gauruntee nature in schema.
>> >
>> > CHANGES SINCE V4:
>> >  - Removed timeout mechanism via worker thread/pthread_cancel due to 
>> > potential memory leak. Will re-introduce guest-side timeout support in 
>> > future version.
>> >  - Fixed up fsfreeze code to use enums specified within the guest agent's 
>> > qapi schema.
>> >  - Fixed memory leak due to a log statement, and added missing cleanup 
>> > functions for heap-allocated g_error objects.
>> >  - Made "mode" param to guest-file-open optional, defaults to "r" 
>> > (read-only)
>> >
>> > CHANGES SINCE V3:
>> >  - Fixed error-handling issues in fsfreeze commands leading to certain 
>> > mounted directories causing freeze/thaw operations to fail
>> >  - Added cleanup hook to thaw filesystems on graceful guest agent exit
>> >  - Removed unused enum values and added additional details to schema 
>> > documentation
>> >  - Fixed build issue that was missed due to deprecated files in source 
>> > tree, removed unused includes
>> >
>> > CHANGES SINCE V2:
>> >  - Rebased on new QAPI code generation framework
>> >  - Dropped ability for QMP to act as a proxy for the guest agent, will be 
>> > added when new QMP server is backported from Anthony's glib tree
>> >  - Replaced negotiation/control events with a simple 2-way handshake 
>> > implemented by a standard RPC (guest-sync)
>> >  - Removed enforcement of "pristine" sessions, state is now 
>> > global/persistant across multiple clients/connections
>> >  - Fixed segfault in logging code
>> >  - Added Jes' filesystem freeze patches
>> >  - General cleanups
>> >
>> > CHANGES SINCE V1:
>> >  - Added guest agent worker thread to execute RPCs in the guest. With this 
>> > in place we have a reliable timeout mechanism for hung commands, currently 
>> > set at 30 seconds.
>> >  - Add framework for registering init/cleanup routines for stateful RPCs 
>> > to clean up after themselves after a timeout.
>> >  - Added the following RPCs: guest-file-{open,close,read,write,seek}, 
>> > guest-shutdown, guest-info, and removed stubs for guest-view-file (now 
>> > deprecated)
>> >  - Added GUEST_AGENT_UP/GUEST_AGENT_DOWN QMP events
>> >  - Switched to a TCP-style host-initiated 3-way handshake for channel 
>> > negotiation, this simplifies client negotiation/interaction over the wire
>> >  - Added configurable log level/log file/pid file options for guest agent
>> >  - Various fixes for bugs/memory leaks and checkpatch.pl fixups
>> >
>> > ISSUES/TODOS:
>> >  - Add unit tests for guest agent wire protocol
>> >
>> > OVERVIEW
>> >
>> > For a better overview of what these patches are meant to accomplish, 
>> > please reference the RFC for virtagent:
>> >
>> > http://comments.gmane.org/gmane.comp.emulators.qemu/96096
>> >
>> > These patches integrate the previous virtagent guest agent work directly 
>> > in QAPI/QMP to leverage it's auto-generated marshalling code. This has 
>> > numerous benefits:
>> >
>> >  - addresses previous concerns over relying on external libraries to 
>> > handle data encapsulation
>> >  - reduces the need for manual unmarshalling of requests/responses, which 
>> > makes adding new RPCs much safer/less error-prone, as well as cutting down 
>> > on redundant code
>> >  - QAPI documentation aligns completely with guest-side RPC implementation
>> >  - is Just Better (TM)
>> >
>> > BUILD/USAGE
>> >
>> > build:
>> >  ./configure --target-list=x86_64-softmmu
>> >  make
>> >  make qemu-ga #should be built on|for target guest
>> HI, Macheal.
>> Is qemu-ga built in guest? if yes, it will require the guest to set up
>> a gcc environment. Can we make it built on the host?
>
> Yes, if the host OS matches the guest OS or if you can cross-compile.
>
> Otherwise I think we'll have to rely on distros making qemu-ga available,
> and/or use the guest tools iso Michael is planning. Another option would
> be to compile qemu-ga statically, but this is probably unfeasible.
>
>>
>> >
>> > start guest:
>> >  qemu \
>> >  -drive file=/home/mdroth/vm/rhel6_64_base.raw,snapshot=off,if=virtio \
>> >  -net nic,model=virtio,macaddr=52:54:00:12:34:00 \
>> >  -net tap,script=/etc/qemu-ifup \
>> >  -vnc :1 -m 1024 --enable-kvm \
>> >  -chardev socket,path=/tmp/qga.sock,server,nowait,id=qga0 \
>> >  -device virtio-serial \
>> >  -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0"
>> >
>> > use guest agent:
>> >  ./qemu-ga -h
>> >  ./qemu-ga -m virtio-serial -p /dev/virtio-ports/org.qemu.guest_agent.0
>> >
>> > start/use qmp:
>> > address@hidden:~$ sudo socat unix-connect:/tmp/qga.sock readline
>> >  {"execute":"guest-sync", "arguments":{"id":1234}}
>> >  {"return": 1234}
>> >
>> >  {"execute":"guest-ping"}
>> >  {"return": {}}
>> >
>> >  {"execute": "guest-info"}
>> >  {"return": {"version": "1.0"}}
>> >
>> >  // write "hello world!\n" to /tmp/testqga
>> >  {"execute":"guest-file-open", 
>> > "arguments":{"path":"/tmp/testqga","mode":"w+"}}
>> >  {"return": 0}
>> >  {"execute":"guest-file-write", 
>> > "arguments":{"handle":0,"buf-b64":"aGVsbG8gd29ybGQhCg=="}}
>> >  {"return": {"count": 13, "eof": false}}
>> >  {"execute":"guest-file-close", "arguments":{"handle":0}}
>> >  {"return": {}}
>> >
>> >  // read back the "hello world!\n" from /tmp/testqga
>> >  {"execute":"guest-file-open", 
>> > "arguments":{"path":"/tmp/testqga","mode":"r"}}
>> >  {"return": 1}
>> >  {"execute":"guest-file-read", "arguments":{"handle":1,"count":1024}}
>> >  {"return": {"buf-b64": "aGVsbG8gd29ybGQhCg==", "count": 13, "eof": true}}
>> >  {"execute":"guest-file-close","arguments":{"handle":1}}
>> >  {"return": {}}

Tested-by: Zhi Yong Wu <address@hidden>

>> >
>> >  Makefile                        |   25 ++-
>> >  configure                       |    1 +
>> >  qapi-schema-guest.json          |  217 +++++++++++++
>> >  qemu-ga.c                       |  671 
>> > +++++++++++++++++++++++++++++++++++++++
>> >  qerror.c                        |   13 +
>> >  qerror.h                        |    6 +
>> >  qga/guest-agent-command-state.c |   73 +++++
>> >  qga/guest-agent-commands.c      |  512 +++++++++++++++++++++++++++++
>> >  qga/guest-agent-core.h          |   31 ++
>> >  9 files changed, 1544 insertions(+), 5 deletions(-)
>> >
>> >
>> >
>>
>>
>>
>
>



-- 
Regards,

Zhi Yong Wu