[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(-) diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 109a947..c5b6dd5 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -55,7 +55,8 @@ VIR_ENUM_IMPL(virDomainTaint, VIR_DOMAIN_TAINT_LAST, "custom-monitor", "high-privileges", "shell-scripts", - "disk-probing"); + "disk-probing", + "external-launch"); VIR_ENUM_IMPL(virDomainVirt, VIR_DOMAIN_VIRT_LAST, "qemu", diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 258289a..071bf50 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -1249,6 +1249,7 @@ enum virDomainTaintFlags { VIR_DOMAIN_TAINT_HIGH_PRIVILEGES, /* Running with undesirably high privileges */ VIR_DOMAIN_TAINT_SHELL_SCRIPTS, /* Network configuration using opaque shell scripts */ VIR_DOMAIN_TAINT_DISK_PROBING, /* Relying on potentially unsafe disk format probing */ + VIR_DOMAIN_TAINT_EXTERNAL_LAUNCH, /* Externally launched guest domain */ VIR_DOMAIN_TAINT_LAST }; diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index dbc9e0c..aa66b55 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -6182,6 +6182,8 @@ virDomainDefPtr qemuParseCommandLine(virCapsPtr caps, if (!(def->name = strndup(val, process - val))) goto no_memory; } + if (STREQ(def->name, "")) + VIR_FREE(def->name); } else if (STREQ(arg, "-M")) { WANT_VALUE(); if (!(def->os.machine = strdup(val))) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 9486594..05643bc 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -4129,7 +4129,7 @@ qemudCanonicalizeMachineFromInfo(virDomainDefPtr def, if (!machine->canonical) continue; - if (STRNEQ(def->os.machine, machine->name)) + if (def->os.machine && STRNEQ(def->os.machine, machine->name)) continue; if (!(*canonical = strdup(machine->canonical))) { @@ -4156,7 +4156,7 @@ qemudCanonicalizeMachineDirect(virDomainDefPtr def, char **canonical) if (!machines[i]->canonical) continue; - if (STRNEQ(def->os.machine, machines[i]->name)) + if (def->os.machine && STRNEQ(def->os.machine, machines[i]->name)) continue; *canonical = machines[i]->canonical; @@ -8347,6 +8347,92 @@ cleanup: } +static virDomainPtr qemuDomainAttach(virConnectPtr conn, + unsigned long long pid, + unsigned int flags) +{ + struct qemud_driver *driver = conn->privateData; + virDomainObjPtr vm = NULL; + virDomainDefPtr def = NULL; + virDomainPtr dom = NULL; + virDomainChrSourceDefPtr monConfig = NULL; + bool monJSON = false; + char *pidfile; + + virCheckFlags(0, NULL); + + qemuDriverLock(driver); + + if (!(def = qemuParseCommandLinePid(driver->caps, pid, + &pidfile, &monConfig, &monJSON))) + goto cleanup; + + if (!monConfig) { + qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("No monitor connection for pid %llu"), + pid); + goto cleanup; + } + if (monConfig->type != VIR_DOMAIN_CHR_TYPE_UNIX) { + qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Cannot connect to monitor connection of type '%s' for pid %llu"), + virDomainChrTypeToString(monConfig->type), pid); + goto cleanup; + } + + if (!(def->name) && + virAsprintf(&def->name, "attach-pid-%llu", pid) < 0) { + virReportOOMError(); + goto cleanup; + } + + if (virDomainObjIsDuplicate(&driver->domains, def, 1) < 0) + goto cleanup; + + if (qemudCanonicalizeMachine(driver, def) < 0) + goto cleanup; + + if (qemuDomainAssignPCIAddresses(def) < 0) + goto cleanup; + + if (!(vm = virDomainAssignDef(driver->caps, + &driver->domains, + def, false))) + goto cleanup; + + def = NULL; + + if (qemuDomainObjBeginJobWithDriver(driver, vm) < 0) + goto cleanup; + + if (qemuProcessAttach(conn, driver, vm, pid, + pidfile, monConfig, monJSON) < 0) { + monConfig = NULL; + goto endjob; + } + + monConfig = NULL; + + dom = virGetDomain(conn, vm->def->name, vm->def->uuid); + if (dom) dom->id = vm->def->id; + +endjob: + if (qemuDomainObjEndJob(vm) == 0) { + vm = NULL; + goto cleanup; + } + +cleanup: + virDomainDefFree(def); + virDomainChrSourceDefFree(monConfig); + if (vm) + virDomainObjUnlock(vm); + qemuDriverUnlock(driver); + VIR_FREE(pidfile); + return dom; +} + + 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 */ .domainOpenConsole = qemuDomainOpenConsole, /* 0.8.6 */ .domainInjectNMI = qemuDomainInjectNMI, /* 0.9.2 */ .domainMigrateBegin3 = qemuDomainMigrateBegin3, /* 0.9.2 */ diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index bbbc36f..affdc20 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -61,6 +61,7 @@ #define VIR_FROM_THIS VIR_FROM_QEMU #define START_POSTFIX ": starting up\n" +#define ATTACH_POSTFIX ": attaching\n" #define SHUTDOWN_POSTFIX ": shutting down\n" /** @@ -1125,31 +1126,34 @@ qemuProcessReadLogFD(int logfd, char *buf, int maxlen, int off) tmpbuf[ret] = '\0'; } + static int qemuProcessWaitForMonitor(struct qemud_driver* driver, virDomainObjPtr vm, virBitmapPtr qemuCaps, off_t pos) { - char *buf; + char *buf = NULL; size_t buf_size = 4096; /* Plenty of space to get startup greeting */ - int logfd; + int logfd = -1; int ret = -1; virHashTablePtr paths = NULL; qemuDomainObjPrivatePtr priv; - if ((logfd = qemuDomainOpenLog(driver, vm, pos)) < 0) - return -1; + if (pos != -1) { + if ((logfd = qemuDomainOpenLog(driver, vm, pos)) < 0) + return -1; - if (VIR_ALLOC_N(buf, buf_size) < 0) { - virReportOOMError(); - return -1; - } + if (VIR_ALLOC_N(buf, buf_size) < 0) { + virReportOOMError(); + return -1; + } - if (qemuProcessReadLogOutput(vm, logfd, buf, buf_size, - qemuProcessFindCharDevicePTYs, - "console", 30) < 0) - goto closelog; + if (qemuProcessReadLogOutput(vm, logfd, buf, buf_size, + qemuProcessFindCharDevicePTYs, + "console", 30) < 0) + goto closelog; + } VIR_DEBUG("Connect monitor to %p '%s'", vm, vm->def->name); if (qemuConnectMonitor(driver, vm) < 0) { @@ -1195,6 +1199,8 @@ closelog: virStrerror(errno, ebuf, sizeof ebuf)); } + VIR_FREE(buf); + return ret; } @@ -2974,6 +2980,194 @@ retry: } +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; + monConfig = NULL; + priv->monJSON = monJSON; + + priv->gotShutdown = false; + + /* + * Normally PCI addresses are assigned in the virDomainCreate + * or virDomainDefine methods. We might still need to assign + * some here to cope with the question of upgrades. Regardless + * we also need to populate the PCi address set cache for later + * use in hotplug + */ + if (qemuCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) { + VIR_DEBUG("Assigning domain PCI addresses"); + /* Populate cache with current addresses */ + if (priv->pciaddrs) { + qemuDomainPCIAddressSetFree(priv->pciaddrs); + priv->pciaddrs = NULL; + } + if (!(priv->pciaddrs = qemuDomainPCIAddressSetCreate(vm->def))) + goto cleanup; + + /* Assign any remaining addresses */ + if (qemuAssignDevicePCISlots(vm->def, priv->pciaddrs) < 0) + goto cleanup; + + priv->persistentAddrs = 1; + } else { + priv->persistentAddrs = 0; + } + + if ((timestamp = virTimestamp()) == NULL) { + virReportOOMError(); + goto cleanup; + } else { + if (safewrite(logfile, timestamp, strlen(timestamp)) < 0 || + safewrite(logfile, ATTACH_POSTFIX, strlen(ATTACH_POSTFIX)) < 0) { + VIR_WARN("Unable to write timestamp to logfile: %s", + virStrerror(errno, ebuf, sizeof ebuf)); + } + + VIR_FREE(timestamp); + } + + qemuDomainObjTaint(driver, vm, VIR_DOMAIN_TAINT_EXTERNAL_LAUNCH, logfile); + + vm->pid = pid; + + VIR_DEBUG("Waiting for monitor to show up"); + if (qemuProcessWaitForMonitor(driver, vm, priv->qemuCaps, -1) < 0) + goto cleanup; + + VIR_DEBUG("Detecting VCPU PIDs"); + if (qemuProcessDetectVcpuPIDs(driver, vm) < 0) + goto cleanup; + + /* If we have -device, then addresses are assigned explicitly. + * If not, then we have to detect dynamic ones here */ + if (!qemuCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) { + VIR_DEBUG("Determining domain device PCI addresses"); + if (qemuProcessInitPCIAddresses(driver, vm) < 0) + goto cleanup; + } + + VIR_DEBUG("Getting initial memory amount"); + qemuDomainObjEnterMonitorWithDriver(driver, vm); + if (qemuMonitorGetBalloonInfo(priv->mon, &vm->def->mem.cur_balloon) < 0) { + qemuDomainObjExitMonitorWithDriver(driver, vm); + goto cleanup; + } + if (qemuMonitorGetStatus(priv->mon, &running) < 0) { + qemuDomainObjExitMonitorWithDriver(driver, vm); + goto cleanup; + } + if (qemuMonitorGetVirtType(priv->mon, &vm->def->virtType) < 0) { + qemuDomainObjExitMonitorWithDriver(driver, vm); + goto cleanup; + } + qemuDomainObjExitMonitorWithDriver(driver, vm); + + if (!virDomainObjIsActive(vm)) + goto cleanup; + + if (running) + virDomainObjSetState(vm, VIR_DOMAIN_RUNNING, + VIR_DOMAIN_RUNNING_UNPAUSED); + else + virDomainObjSetState(vm, VIR_DOMAIN_PAUSED, VIR_DOMAIN_PAUSED_UNKNOWN); + + VIR_DEBUG("Writing domain status to disk"); + if (virDomainSaveStatus(driver->caps, driver->stateDir, vm) < 0) + goto cleanup; + + VIR_FORCE_CLOSE(logfile); + VIR_FREE(seclabel); + + return 0; + +no_memory: + virReportOOMError(); +cleanup: + /* We jump here if we failed to start the VM for any reason, or + * if we failed to initialize the now running VM. kill it off and + * pretend we never started it */ + VIR_FORCE_CLOSE(logfile); + VIR_FREE(seclabel); + virDomainChrSourceDefFree(monConfig); + return -1; +} + + int qemuProcessAutoDestroyInit(struct qemud_driver *driver) { if (!(driver->autodestroy = virHashCreate(5, NULL))) diff --git a/src/qemu/qemu_process.h b/src/qemu/qemu_process.h index 0e74d2a..449d7f1 100644 --- a/src/qemu/qemu_process.h +++ b/src/qemu/qemu_process.h @@ -56,6 +56,14 @@ void qemuProcessStop(struct qemud_driver *driver, int migrated, virDomainShutoffReason reason); +int qemuProcessAttach(virConnectPtr conn, + struct qemud_driver *driver, + virDomainObjPtr vm, + int pid, + const char *pidfile, + virDomainChrSourceDefPtr monConfig, + bool monJSON); + void qemuProcessKill(virDomainObjPtr vm); int qemuProcessAutoDestroyInit(struct qemud_driver *driver); -- 1.7.4.4