[Libvir] [QEMU 3/3] the qemu driver & daemon

Attached is the patch for the qemu driver & daemon process Since there is no scalable way to determine active standalone QEMU instances, or access their monitor connection, the backend implements a management daemon - called 'qemud' - which takes care of managing the complete lifecycle of QEMU virtual machines. The libvirt driver is a thin shim which talks to qemud via a UNIX domain socket - the wire protocol is modelled after the protocol used for libvirt_proxy, but obviously contains alot more functions since its full read/write, not just read-only. There is intended to be one qemud instance per UNIX user - the so called 'session' instance, and optionally one system global instance runing as root (or a system daemon account?) - the so called 'system' instance. When using libvirt, the URIs for each are 'qemu:///session' and 'qemu:///system' respectively. The UNIX socket for session instances is $HOME/.qemud and is chmod 0700 - no support is provided for users connecting to each other's instances. Although we could trivially extend to create a read-only socket $HOME/.qemud-ro if desired. The system instance is currently not finished but intended to run in /var/run/qemud or some such. The backend code is in src/qemu_internal.h, src/qemu_internal.c, the daemon code is in qemud/* with qemud/protocol.h defining the network wire protocol. This latter header file is also included by src/qemu_internal.c - qemud.c - the main daemon management code - handles all network I/O and forking / cleanup of QEMU processes. The implementation is poll() based & completely non-blocking. All requests/replies from a single client are, however, serialized. - dispatch.c - takes care of serializing/de-serializing requests/replies from/to libvirt - called from qemud.c when a complete message is available. - driver.c - the implementation of each request from libvirt - called from dispatch.c - config.c - manages reading & writing of XML files for inactive domains in the $HOME/.qemud.d/*.xml. Also takes care of generating a suitable command line for execing qemu. In terms of hardware, there is support for - harddisk - floppy, cdrom, harddisk - graphics - VNC - memory - virtual CPUs In particular no support for - networking - sound - non-native CPU types - boot order But its enough to demonstrate the practice. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|