Re: [libvirt] [PATCH 3/4] Add support for detecting capablities using QMP commands

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; Start a QEMU process using $QEMU -S -no-user-config -nodefaults \ -nographic -M none -qmp unix:/some/path,server,nowait and talk QMP over stdio to discover what capabilities the binary supports. This works for QEMU 1.2.0 or later and for older QEMU automatically fallback to the old approach of parsing -help and related command line args. Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- src/qemu/qemu_capabilities.c | 394 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 358 insertions(+), 36 deletions(-)

+ +/* Capabilities that we assume are always enabled + * for QEMU >= 1.2.0 + */ +static void +qemuCapsInitQMPBasic(qemuCapsPtr caps) +{ + qemuCapsSet(caps, QEMU_CAPS_VNC_COLON); + qemuCapsSet(caps, QEMU_CAPS_NO_REBOOT);

+ +static int +qemuCapsInitQMP(qemuCapsPtr caps) +{ + int ret = -1; + virCommandPtr cmd = NULL; + qemuMonitorPtr mon = NULL; + int major, minor, micro; + char *package; + int status = 0; + virDomainChrSourceDef config; + + memset(&config, 0, sizeof(config)); + config.type = VIR_DOMAIN_CHR_TYPE_UNIX; + config.data.nix.path = (char*)"/tmp/qemu.sock";

+ config.data.nix.listen = false; + + VIR_DEBUG("Try to get caps via QMP caps=%p", caps); + + cmd = virCommandNewArgList(caps->binary, + "-S", + "-no-user-config", + "-nodefaults", + "-nographic", + "-M", "none", + "-qmp", "unix:/tmp/qemu.sock,server,nowait",