Re: [libvirt] [PATCH 8/8] Implement code to attach to external QEMU instances.

Given a PID, the QEMU driver reads /proc/$PID/cmdline and /proc/$PID/environ to get the configuration. This is fed into the ARGV->XML convertor to build an XML configuration for the process. /proc/$PID/exe is resolved to identify the full command binary path After checking for name/uuid uniqueness, an attempt is made to connect to the monitor socket. If successful then 'info status' and 'info kvm' are issued to determine whether the CPUs are running and if KVM is enabled. * src/qemu/qemu_driver.c: Implement virDomainQemuAttach * src/qemu/qemu_process.h, src/qemu/qemu_process.c: Add  qemuProcessAttach to connect to the monitor of an  existing QEMU process ---  src/conf/domain_conf.c  |    3 +-  src/conf/domain_conf.h  |    1 +  src/qemu/qemu_command.c |    2 +  src/qemu/qemu_driver.c  |   91 +++++++++++++++++++-  src/qemu/qemu_process.c |  218 ++++++++++++++++++++++++++++++++++++++++++++---  src/qemu/qemu_process.h |    8 ++  6 files changed, 308 insertions(+), 15 deletions(-)

 static int  qemuDomainOpenConsole(virDomainPtr dom,                       const char *devname, @@ -8539,6 +8625,7 @@ static virDriver qemuDriver = {     .domainRevertToSnapshot = qemuDomainRevertToSnapshot, /* 0.8.0 */     .domainSnapshotDelete = qemuDomainSnapshotDelete, /* 0.8.0 */     .qemuDomainMonitorCommand = qemuDomainMonitorCommand, /* 0.8.3 */ +    .qemuDomainAttach = qemuDomainAttach, /* 0.9.3 */

+int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED, +                      struct qemud_driver *driver, +                      virDomainObjPtr vm, +                      int pid, +                      const char *pidfile, +                      virDomainChrSourceDefPtr monConfig, +                      bool monJSON) +{ +    char ebuf[1024]; +    int logfile = -1; +    char *timestamp; +    qemuDomainObjPrivatePtr priv = vm->privateData; +    bool running = true; +    virSecurityLabelPtr seclabel = NULL; + +    VIR_DEBUG("Beginning VM attach process"); + +    if (virDomainObjIsActive(vm)) { +        qemuReportError(VIR_ERR_OPERATION_INVALID, +                        "%s", _("VM is already active")); +        return -1; +    } + +    /* Do this upfront, so any part of the startup process can add +     * runtime state to vm->def that won't be persisted. This let's us +     * report implicit runtime defaults in the XML, like vnc listen/socket +     */ +    VIR_DEBUG("Setting current domain def as transient"); +    if (virDomainObjSetDefTransient(driver->caps, vm, true) < 0) +        goto cleanup; + +    vm->def->id = driver->nextvmid++; + +    if (virFileMakePath(driver->logDir) != 0) { +        virReportSystemError(errno, +                             _("cannot create log directory %s"), +                             driver->logDir); +        goto cleanup; +    }

+    VIR_FREE(priv->pidfile); +    if (pidfile && +        !(priv->pidfile = strdup(pidfile))) +        goto no_memory; + +    VIR_DEBUG("Detect security driver config"); +    vm->def->seclabel.type = VIR_DOMAIN_SECLABEL_STATIC; +    if (VIR_ALLOC(seclabel) < 0) +        goto no_memory; +    if (virSecurityManagerGetProcessLabel(driver->securityManager, +                                          vm, seclabel) < 0) +        goto cleanup; +    if (!(vm->def->seclabel.model = strdup(driver->caps->host.secModel.model))) +        goto no_memory; +    if (!(vm->def->seclabel.label = strdup(seclabel->label))) +        goto no_memory; + +    VIR_DEBUG("Creating domain log file"); +    if ((logfile = qemuDomainCreateLog(driver, vm, false)) < 0) +        goto cleanup; + +    VIR_DEBUG("Determining emulator version"); +    qemuCapsFree(priv->qemuCaps); +    priv->qemuCaps = NULL; +    if (qemuCapsExtractVersionInfo(vm->def->emulator, +                                   vm->def->os.arch, +                                   NULL, +                                   &priv->qemuCaps) < 0) +        goto cleanup; + +    if (VIR_ALLOC(priv->monConfig) < 0) { +        virReportOOMError(); +        goto cleanup; +    } + +    VIR_DEBUG("Preparing monitor state"); +    priv->monConfig = monConfig;