Re: [libvirt] [PATCH RFC 3/4] libxl: implement qemu-agent-command

Signed-off-by: Joao Martins <joao.m.martins(a)oracle.com&gt; --- src/libxl/libxl_domain.c | 239 ++++++++++++++++++++++++++++++++++++++++++++++- src/libxl/libxl_domain.h | 16 ++++ src/libxl/libxl_driver.c | 51 ++++++++++ 3 files changed, 305 insertions(+), 1 deletion(-) diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index ed73cd2..6bdd0ec 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -782,6 +782,12 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver, } } + if (priv->agent) { + qemuAgentClose(priv->agent); + priv->agent = NULL; + priv->agentError = false; + } + if ((vm->def->nnets)) { size_t i; @@ -940,6 +946,228 @@ libxlDomainFreeMem(libxl_ctx *ctx, libxl_domain_config *d_config) return -1; } +/* + * This is a callback registered with a qemuAgentPtr instance, + * and to be invoked when the agent console hits an end of file + * condition, or error, thus indicating VM shutdown should be + * performed + */ +static void +libxlHandleAgentEOF(qemuAgentPtr agent, + virDomainObjPtr vm)

+{ + libxlDomainObjPrivatePtr priv; + + VIR_DEBUG("Received EOF from agent on %p '%s'", vm, vm->def->name); + + virObjectLock(vm); + + priv = vm->privateData; + + if (!priv->agent) { + VIR_DEBUG("Agent freed already"); + goto unlock; + } + + qemuAgentClose(agent); + priv->agent = NULL;

+ + unlock: + virObjectUnlock(vm); + return; +} + + +/* + * This is invoked when there is some kind of error + * parsing data to/from the agent. The VM can continue + * to run, but no further agent commands will be + * allowed + */ +static void +libxlHandleAgentError(qemuAgentPtr agent ATTRIBUTE_UNUSED, + virDomainObjPtr vm)

+{ + libxlDomainObjPrivatePtr priv; + + VIR_DEBUG("Received error from agent on %p '%s'", vm, vm->def->name); + + virObjectLock(vm); + + priv = vm->privateData; + + priv->agentError = true; + + virObjectUnlock(vm); +} + +static void libxlHandleAgentDestroy(qemuAgentPtr agent, + virDomainObjPtr vm) +{ + VIR_DEBUG("Received destroy agent=%p vm=%p", agent, vm); + + virObjectUnref(vm); +} + +static qemuAgentCallbacks agentCallbacks = { + .destroy = libxlHandleAgentDestroy, + .eofNotify = libxlHandleAgentEOF, + .errorNotify = libxlHandleAgentError, +}; + +static virDomainChrDefPtr +libxlFindAgentConfig(virDomainDefPtr def) +{ + size_t i; + + for (i = 0; i < def->nchannels; i++) { + virDomainChrDefPtr channel = def->channels[i]; + + if (channel->targetType != VIR_DOMAIN_CHR_CHANNEL_TARGET_TYPE_XEN) + continue; + + if (STREQ_NULLABLE(channel->target.name, "org.qemu.guest_agent.0")) + return channel; + } + + return NULL; +} + +bool +libxlDomainAgentAvailable(virDomainObjPtr vm, bool reportError)

+{ + libxlDomainObjPrivatePtr priv = vm->privateData; + + if (virDomainObjGetState(vm, NULL) != VIR_DOMAIN_RUNNING) { + if (reportError) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("domain is not running")); + } + return false; + } + if (priv->agentError) { + if (reportError) { + virReportError(VIR_ERR_AGENT_UNRESPONSIVE, "%s", + _("QEMU guest agent is not " + "available due to an error")); + } + return false; + } + if (!priv->agent) { + if (libxlFindAgentConfig(vm->def)) { + if (reportError) { + virReportError(VIR_ERR_AGENT_UNRESPONSIVE, "%s", + _("QEMU guest agent is not connected")); + } + return false; + } else { + if (reportError) { + virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s", + _("QEMU guest agent is not configured")); + } + return false; + } + } + return true; +} + +static int +libxlConnectAgent(virDomainObjPtr vm) +{ + virDomainChrDefPtr config = libxlFindAgentConfig(vm->def); + libxlDomainObjPrivatePtr priv = vm->privateData; + qemuAgentPtr agent = NULL; + int ret = -1; + + if (!config) + return 0; + + if (priv->agent) + return 0; + + /* Hold an extra reference because we can't allow 'vm' to be + * deleted while the agent is active */ + virObjectRef(vm); + + ignore_value(virTimeMillisNow(&priv->agentStart)); + virObjectUnlock(vm); + + agent = qemuAgentOpen(vm, config->source, &agentCallbacks); + + virObjectLock(vm); + priv->agentStart = 0; + + if (agent == NULL) + virObjectUnref(vm); + + if (!virDomainObjIsActive(vm)) { + qemuAgentClose(agent); + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("guest crashed while connecting to the guest agent")); + ret = -2;

+ goto cleanup; + } + + priv->agent = agent; + + if (priv->agent == NULL) { + VIR_INFO("Failed to connect agent for %s", vm->def->name); + goto cleanup; + } + + ret = 0; + + cleanup: + return ret;

+} + +/* + * obj must be locked before calling + * + * To be called immediately before any QEMU agent API call. + * Must have already called libxlDomainObjBeginJob() and checked + * that the VM is still active. + * + * To be followed with libxlDomainObjExitAgent() once complete + */ +void +libxlDomainObjEnterAgent(virDomainObjPtr obj) +{ + libxlDomainObjPrivatePtr priv = obj->privateData; + + VIR_DEBUG("Entering agent (agent=%p vm=%p name=%s)", + priv->agent, obj, obj->def->name); + virObjectLock(priv->agent); + virObjectRef(priv->agent); + ignore_value(virTimeMillisNow(&priv->agentStart)); + virObjectUnlock(obj); +} + + +/* obj must NOT be locked before calling + * + * Should be paired with an earlier qemuDomainObjEnterAgent() call + */ +void +libxlDomainObjExitAgent(virDomainObjPtr obj) +{ + libxlDomainObjPrivatePtr priv = obj->privateData; + bool hasRefs; + + hasRefs = virObjectUnref(priv->agent); + + if (hasRefs) + virObjectUnlock(priv->agent); + + virObjectLock(obj); + VIR_DEBUG("Exited agent (agent=%p vm=%p name=%s)", + priv->agent, obj, obj->def->name); + + priv->agentStart = 0; + if (!hasRefs) + priv->agent = NULL; +} + static int libxlNetworkPrepareDevices(virDomainDefPtr def) { @@ -1312,8 +1540,17 @@ libxlDomainStart(libxlDriverPrivatePtr driver, libxlDomainCreateIfaceNames(vm->def, &d_config); #ifdef LIBXL_HAVE_DEVICE_CHANNEL - if (vm->def->nchannels > 0) + if (vm->def->nchannels > 0) { libxlDomainCreateChannelPTY(vm->def, cfg->ctx); + + /* Failure to connect to agent shouldn't be fatal */ + if (libxlConnectAgent(vm) < 0) { + VIR_WARN("Cannot connect to QEMU guest agent for %s", + vm->def->name); + virResetLastError(); + priv->agentError = true; + } + } #endif if ((dom_xml = virDomainDefFormat(vm->def, cfg->caps, 0)) == NULL) diff --git a/src/libxl/libxl_domain.h b/src/libxl/libxl_domain.h index 3a3890b..59f9f8d 100644 --- a/src/libxl/libxl_domain.h +++ b/src/libxl/libxl_domain.h @@ -29,6 +29,7 @@ # include "domain_conf.h" # include "libxl_conf.h" # include "virchrdev.h" +# include "virqemuagent.h" # define JOB_MASK(job) (1 << (job - 1)) # define DEFAULT_JOB_MASK \ @@ -62,6 +63,11 @@ typedef libxlDomainObjPrivate *libxlDomainObjPrivatePtr; struct _libxlDomainObjPrivate { virObjectLockable parent; + /* agent */ + qemuAgentPtr agent; + bool agentError; + unsigned long long agentStart; + /* console */ virChrdevsPtr devs; libxl_evgen_domain_death *deathW; @@ -91,6 +97,16 @@ void libxlDomainObjEndJob(libxlDriverPrivatePtr driver, virDomainObjPtr obj); +bool +libxlDomainAgentAvailable(virDomainObjPtr vm, + bool reportError); + +void +libxlDomainObjEnterAgent(virDomainObjPtr obj); + +void +libxlDomainObjExitAgent(virDomainObjPtr obj); + int libxlDomainJobUpdateTime(struct libxlDomainJobObj *job) ATTRIBUTE_RETURN_CHECK; diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 3a69720..cf5e702 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -57,6 +57,7 @@ #include "virstring.h" #include "virsysinfo.h" #include "viraccessapicheck.h" +#include "viraccessapicheckqemu.h" #include "viratomic.h" #include "virhostdev.h" #include "network/bridge_driver.h" @@ -6415,6 +6416,55 @@ libxlConnectBaselineCPU(virConnectPtr conn, return cpu; } +static char * +libxlDomainQemuAgentCommand(virDomainPtr domain, + const char *cmd, + int timeout, + unsigned int flags) +{ + libxlDriverPrivatePtr driver = domain->conn->privateData; + virDomainObjPtr vm; + int ret = -1; + char *result = NULL; + libxlDomainObjPrivatePtr priv; + + virCheckFlags(0, NULL); + + if (!(vm = libxlDomObjFromDomain(domain))) + goto cleanup; + + priv = vm->privateData; + + if (virDomainQemuAgentCommandEnsureACL(domain->conn, vm->def) < 0) + goto cleanup; + + if (libxlDomainObjBeginJob(driver, vm, LIBXL_JOB_MODIFY) < 0) + goto cleanup; + + if (!virDomainObjIsActive(vm)) { + virReportError(VIR_ERR_OPERATION_INVALID, + "%s", _("domain is not running")); + goto endjob; + } + + if (!libxlDomainAgentAvailable(vm, true)) + goto endjob; + + libxlDomainObjEnterAgent(vm); + ret = qemuAgentArbitraryCommand(priv->agent, cmd, &result, timeout); + libxlDomainObjExitAgent(vm); + if (ret < 0) + VIR_FREE(result); + + endjob: + libxlDomainObjEndJob(driver, vm); + + cleanup: + virDomainObjEndAPI(&vm); + return result; +} + + static virHypervisorDriver libxlHypervisorDriver = { .name = LIBXL_DRIVER_NAME, .connectOpen = libxlConnectOpen, /* 0.9.0 */ @@ -6522,6 +6572,7 @@ static virHypervisorDriver libxlHypervisorDriver = { .connectGetDomainCapabilities = libxlConnectGetDomainCapabilities, /* 2.0.0 */ .connectCompareCPU = libxlConnectCompareCPU, /* 2.3.0 */ .connectBaselineCPU = libxlConnectBaselineCPU, /* 2.3.0 */ + .domainQemuAgentCommand = libxlDomainQemuAgentCommand, /* 3.1.0 */