On 12/2/19 10:03 AM, Daniel P. Berrangé wrote: I would expect to see a newline here Reviewed-by: Cole Robinson <crobinso(a)redhat.com&gt; - Cole

On 12/2/19 10:03 AM, Daniel P. Berrangé wrote: Other files I looked at, this comes before VIR_LOG_INIT, but I don't think that has any effect Spacing is inconsistent here, there's two lines before the function and one after Reviewed-by: Cole Robinson <crobinso(a)redhat.com&gt; - Cole

The driver URI scheme: "$drivername:///embed?root=/some/path" enables a new way to use the drivers by embedding them directly in the calling process. To use this the process must have a thread running the libvirt event loop. This URI will then cause libvirt to dynamically load the driver module and call its global initialization function. This syntax is applicable to any driver, but only those will have been modified to support a custom root directory and embed URI path will successfully open. The application can now make normal libvirt API calls which are all serviced in-process with no RPC layer involved. It is required to specify an explicit root directory, and locks will be acquired on this directory to avoid conflicting with another app that might accidentally pick the same directory. Use of '/' is not explicitly forbidden, but note that the file layout used underneath the embedded driver root does not match the file layout used by system/session mode drivers. So this cannot be used as a backdoor to interact with, or fake, the system/session mode drivers. Libvirt will create arbitrary files underneath this root directory. The root directory can be kept untouched across connection open attempts if the application needs persistence. The application is responsible for purging everything underneath this root directory when finally no longer required. Even when a virt driver is used in embedded mode, it is still possible for it to in turn use functionality that calls out to other secondary drivers in libvirtd. For example an embedded instance of QEMU can open the network, secret or storage drivers in the system libvirtd. That said, the application would typically want to at least open an embedded secret driver ("secret:///embed?root=/some/path"). Note that multiple different embedded drivers can use the same root prefix and co-operate just as they would inside a normal libvirtd daemon. A key thing to note is that for this to work, the application that links to libvirt *MUST* be built with -Wl,--export-dynamic to ensure that symbols from libvirt.so are exported & thus available to the dynamically loaded driver module. If libvirt.so itself was dynamically loaded then RTLD_GLOBAL must be passed to dlopen(). Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- src/driver-state.h | 1 + src/driver.h | 2 ++ src/libvirt.c | 72 ++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 73 insertions(+), 2 deletions(-) diff --git a/src/driver-state.h b/src/driver-state.h index 1e2f6ed247..6b3f501e05 100644 --- a/src/driver-state.h +++ b/src/driver-state.h @@ -50,6 +50,7 @@ typedef virStateDriver *virStateDriverPtr; struct _virStateDriver { const char *name; + bool initialized; virDrvStateInitialize stateInitialize; virDrvStateCleanup stateCleanup; virDrvStateReload stateReload; diff --git a/src/driver.h b/src/driver.h index ca82ac974b..6278aa05b3 100644 --- a/src/driver.h +++ b/src/driver.h @@ -82,6 +82,8 @@ struct _virConnectDriver { bool localOnly; /* Whether driver needs a server in the URI */ bool remoteOnly; + /* Whether driver can be used in embedded mode */ + bool embeddable; /* * NULL terminated list of supported URI schemes. * - Single element { NULL } list indicates no supported schemes diff --git a/src/libvirt.c b/src/libvirt.c index bd2952d036..17b6506faa 100644 --- a/src/libvirt.c +++ b/src/libvirt.c @@ -52,6 +52,7 @@ # include "rpc/virnettlscontext.h" #endif #include "vircommand.h" +#include "virevent.h" #include "virfile.h" #include "virrandom.h" #include "viruri.h" @@ -84,6 +85,7 @@ #ifdef WITH_BHYVE # include "bhyve/bhyve_driver.h" #endif +#include "access/viraccessmanager.h" #define VIR_FROM_THIS VIR_FROM_NONE @@ -676,10 +678,12 @@ virStateInitialize(bool privileged, return -1; for (i = 0; i < virStateDriverTabCount; i++) { - if (virStateDriverTab[i]->stateInitialize) { + if (virStateDriverTab[i]->stateInitialize && + !virStateDriverTab[i]->initialized) { virDrvStateInitResult ret; VIR_DEBUG("Running global init for %s state driver", virStateDriverTab[i]->name); + virStateDriverTab[i]->initialized = true; ret = virStateDriverTab[i]->stateInitialize(privileged, root, callback, @@ -872,6 +876,7 @@ virConnectOpenInternal(const char *name, virConnectPtr ret; g_autoptr(virConf) conf = NULL; char *uristr = NULL; + bool embed = false; ret = virGetConnect(); if (ret == NULL) @@ -962,6 +967,52 @@ virConnectOpenInternal(const char *name, ret->uri) < 0) { goto failed; } + + if (STREQ(ret->uri->path, "/embed")) { + const char *root = NULL; + g_autofree char *regMethod = NULL; + VIR_DEBUG("URI path requests %s driver embedded mode", + ret->uri->scheme); + if (strspn(ret->uri->scheme, "abcdefghijklmnopqrstuvwxyz") != + strlen(ret->uri->scheme)) { + virReportError(VIR_ERR_NO_CONNECT, + _("URI scheme '%s' for embedded driver is not valid"), + ret->uri->scheme); + goto failed; + } + + for (i = 0; i < ret->uri->paramsCount; i++) { + virURIParamPtr var = &ret->uri->params[i]; + if (STREQ(var->name, "root")) + root = var->value; + } + + if (!root) { + virReportError(VIR_ERR_INVALID_ARG, "%s", + _("root parameter required for embedded driver")); + goto failed; + } + + if (virEventRequireImpl() < 0) + goto failed; + + regMethod = g_strdup_printf("%sRegister", ret->uri->scheme); + + if (virDriverLoadModule(ret->uri->scheme, regMethod, false) < 0) + goto failed; + + if (virAccessManagerGetDefault() == NULL) { + virAccessManagerPtr acl = virAccessManagerNew("none"); + if (!acl) + goto failed; + virAccessManagerSetDefault(acl); + } + + if (virStateInitialize(geteuid() == 0, true, root, NULL, NULL) < 0) + goto failed; + + embed = true; + } } else { VIR_DEBUG("no name, allowing driver auto-select"); } @@ -1018,6 +1069,12 @@ virConnectOpenInternal(const char *name, VIR_DEBUG("No URI, skipping driver with URI whitelist"); continue; } + if (embed && !virConnectDriverTab[i]->embeddable) { + VIR_DEBUG("Ignoring non-embeddable driver %s", + virConnectDriverTab[i]->hypervisorDriver->name); + continue; + } + VIR_DEBUG("Checking for supported URI schemes"); for (s = 0; virConnectDriverTab[i]->uriSchemes[s] != NULL; s++) { if (STREQ(ret->uri->scheme, virConnectDriverTab[i]->uriSchemes[s])) { @@ -1031,9 +1088,20 @@ virConnectOpenInternal(const char *name, continue; } } else { - VIR_DEBUG("Matching any URI scheme for '%s'", ret->uri ? ret->uri->scheme : ""); + if (embed) { + VIR_DEBUG("Skipping wildcard for embedded URI"); + continue; + } else { + VIR_DEBUG("Matching any URI scheme for '%s'", ret->uri ? ret->uri->scheme : ""); + } } + if (embed && !virConnectDriverTab[i]->embeddable) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Driver %s cannot be used in embedded mode"), + virConnectDriverTab[i]->hypervisorDriver->name); + goto failed; + } /* before starting the new connection, check if the driver only works * with a server, and so return an error if the server is missing */ if (virConnectDriverTab[i]->remoteOnly && ret->uri && !ret->uri->server) { -- 2.23.0

On 12/17/19 6:41 PM, Cole Robinson wrote: I didn't get this far, when I wanted to run virt-install all I can see is the following error: [Tue, 17 Dec 2019 20:22:39 virt-install 129850] ERROR (cli:259) this function is not supported by the connection driver: An event loop implementation must be registered which I tracked to here: <no frame> <no attribute num on current thread> $ r /home/zippy/work/virt-manager.git/virt-install --connect "qemu:///embed?root=/tmp/a" --name f31-uefi --ram 2048 --disk none --boot uefi --import --debug Starting program: /usr/bin/python /home/zippy/work/virt-manager.git/virt-install --connect "qemu:///embed?root=/tmp/a" --name f31-uefi --ram 2048 --disk none --boot uefi --import --debug process 129850 is executing new program: /usr/bin/python3.6m [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". [Tue, 17 Dec 2019 20:21:34 virt-install 129850] DEBUG (cli:203) Launched with command line: /home/zippy/work/virt-manager.git/virt-install --connect qemu:///embed?root=/tmp/a --name f31-uefi --ram 2048 --disk none --boot uefi --import --debug [Tue, 17 Dec 2019 20:21:34 virt-install 129850] DEBUG (virt-install:208) Distilled --network options: ['default'] [Tue, 17 Dec 2019 20:21:34 virt-install 129850] DEBUG (virt-install:140) Distilled --disk options: ['none'] [Tue, 17 Dec 2019 20:21:34 virt-install 129850] DEBUG (cli:219) Requesting libvirt URI qemu:///embed?root=/tmp/a Breakpoint 1, virEventRequireImpl () at ../../src/util/virevent.c:268 268 if (!addHandleImpl || !addTimeoutImpl) { virEventRequireImpl 1 $ bt #0 0x00007ffff693ca53 in virEventRequireImpl () at ../../src/util/virevent.c:268 #1 0x00007ffff6bd2c33 in virConnectOpenInternal (name=0x7ffff710bdd0 "qemu:///embed?root=/tmp/a", auth=0x7fffffffc8a0, flags=0) at ../../src/libvirt.c:996 #2 0x00007ffff6bd38ab in virConnectOpenAuth (name=0x7ffff710bdd0 "qemu:///embed?root=/tmp/a", auth=0x7fffffffc8a0, flags=0) at ../../src/libvirt.c:1272 #3 0x00007ffff6e17b55 in libvirt_virConnectOpenAuth () at /usr/lib64/python3.6/site-packages/libvirtmod.cpython-36m-x86_64-linux-gnu.so But this looks weird, isn't virt-install registerin an event loop? How else does it get events? Michal

On Tue, Dec 17, 2019 at 12:41:27PM -0500, Cole Robinson wrote: Right, so because of our design with the single global driver struct, we can only have 1 instance of the driver active per process. So yeah, we need to enforce this in some place or other. It should be valid to open multiple connections to the same embedded driver instance directory though. Hard to tell but my guess is that there's probably some event loop interaction causing us problems. Obviously this stack trace is waiting for the job lock. I'm guessing that the job lock is held by another API call made from the event loop thread. Will investigate it some more. In libvirtd no libvirt APIs calls are ever made from the event loop thread, they can only be made from worker threads. We'll need to make it clear that apps using the embedded driver must likewise ensure that libvirt APIs calls are *NEVER* made from the event loop thread. This is good practice even when using traditional libvirt connections, because the RPC calls to libvirtd can take an arbitrary amount of time to complete & so make the event loop response very poor. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|

This enables support for running QEMU embedded to the calling application process using a URI: qemu:///embed?root=/some/path Note that it is important to keep the path reasonably short to avoid risk of hitting the limit on UNIX socket path names which is 108 characters. When using the embedded mode with a root=/var/tmp/embed, the driver will use the following paths: logDir: /var/tmp/embed/log/qemu swtpmLogDir: /var/tmp/embed/log/swtpm configBaseDir: /var/tmp/embed/etc/qemu stateDir: /var/tmp/embed/run/qemu swtpmStateDir: /var/tmp/embed/run/swtpm cacheDir: /var/tmp/embed/cache/qemu libDir: /var/tmp/embed/lib/qemu swtpmStorageDir: /var/tmp/embed/lib/swtpm defaultTLSx509certdir: /var/tmp/embed/etc/pki/qemu These are identical whether the embedded driver is privileged or unprivileged. This compares with the system instance which uses logDir: /var/log/libvirt/qemu swtpmLogDir: /var/log/swtpm/libvirt/qemu configBaseDir: /etc/libvirt/qemu stateDir: /run/libvirt/qemu swtpmStateDir: /run/libvirt/qemu/swtpm cacheDir: /var/cache/libvirt/qemu libDir: /var/lib/libvirt/qemu swtpmStorageDir: /var/lib/libvirt/swtpm defaultTLSx509certdir: /etc/pki/qemu At this time all features present in the QEMU driver are available when running in embedded mode, availability matching whether the embedded driver is privileged or unprivileged. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- docs/drvqemu.html.in | 84 +++++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_conf.c | 38 +++++++++++++++++-- src/qemu/qemu_conf.h | 6 ++- src/qemu/qemu_driver.c | 26 +++++++------ src/qemu/qemu_process.c | 15 ++++++-- tests/domaincapstest.c | 2 +- tests/testutilsqemu.c | 2 +- 7 files changed, 151 insertions(+), 22 deletions(-) diff --git a/docs/drvqemu.html.in b/docs/drvqemu.html.in index 294117ee1f..4bcf5ac002 100644 --- a/docs/drvqemu.html.in +++ b/docs/drvqemu.html.in @@ -63,6 +63,90 @@ qemu+tcp://example.com/system (remote access, SASl/Kerberos) qemu+ssh://root@example.com/system (remote access, SSH tunnelled) </pre> + <h3><a id="uriembedded">Embedded driver</a></h3> + + <p> + Since 6.0.0 the QEMU driver has experimental support for operating + in an embedded mode. In this scenario, rather than connecting to + the libvirtd daemon, the QEMU driver runs in the client application + process directly. To use this the client application must have + registered &amp; be running an instance of the event loop. To open + the driver in embedded mode the app use the new URI path and specify + a virtual root directory under which the driver will create content. + </p> + + <pre> + qemu:///embed?root=/some/dir + </pre> + + <p> + Under the specified root directory the following locations will + be used + </p> + + <pre> +/some/dir + | + +- log + | | + | +- qemu + | +- swtpm + | + +- etc + | | + | +- qemu + | +- pki + | | + | +- qemu + | + +- run + | | + | +- qemu + | +- swtpm + | + +- cache + | | + | +- qemu + | + +- lib + | + +- qemu + +- swtpm + </pre> + + <p> + Note that UNIX domain sockets used for QEMU virtual machines had + a maximum filename length of 108 characters. Bear this in mind + when picking a root directory to avoid risk of exhausting the + filename space. The application is responsible for recursively + purging the contents of this directory tree once they no longer + require a connection, though it can also be left intact for reuse + when opening a future connection. + </p> + + <p> + Broadly speaking the range of functionality is intended to be + on a par with that seen when using the traditional system or + session libvirt connections to QEMU. The features will of course + differ depending on whether the application using the embedded + driver is running privileged or unprivileged. For example PCI + device assignment or TAP based networking are only available + when running privileged. While the embedded mode is still classed + as experimental some features may change their default settings + between releases. + </p> + + <p> + By default if the application uses any APIs associated with + secondary drivers, these will result in a connection being + opened to the corresponding driver in libvirtd. For example, + this allows a virtual machine from the embedded QEMU to connect + its NIC to a virtual network or connect its disk to a storage + volume. Some of the secondary drivers will also be able to support + running in embedded mode. Currently this is supported by the + secrets driver, to allow for use of VMs with encrypted disks + </p> + <h2><a id="security">Driver security architecture</a></h2> <p> diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index 30637b21ac..e2b4c26b9b 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -104,7 +104,8 @@ qemuDriverUnlock(virQEMUDriverPtr driver) #endif -virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged) +virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged, + const char *root) { g_autoptr(virQEMUDriverConfig) cfg = NULL; @@ -130,7 +131,24 @@ virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged) cfg->cgroupControllers = -1; /* -1 == auto-detect */ - if (privileged) { + if (root != NULL) { + cfg->logDir = g_strdup_printf("%s/log/qemu", root); + cfg->swtpmLogDir = g_strdup_printf("%s/log/swtpm", root); + cfg->configBaseDir = g_strdup_printf("%s/etc", root); + cfg->stateDir = g_strdup_printf("%s/run/qemu", root); + cfg->swtpmStateDir = g_strdup_printf("%s/run/swtpm", root); + cfg->cacheDir = g_strdup_printf("%s/cache/qemu", root); + cfg->libDir = g_strdup_printf("%s/lib/qemu", root); + cfg->swtpmStorageDir = g_strdup_printf("%s/lib/swtpm", root); + + cfg->saveDir = g_strdup_printf("%s/save", cfg->libDir); + cfg->snapshotDir = g_strdup_printf("%s/snapshot", cfg->libDir); + cfg->checkpointDir = g_strdup_printf("%s/checkpoint", cfg->libDir); + cfg->autoDumpPath = g_strdup_printf("%s/dump", cfg->libDir); + cfg->channelTargetDir = g_strdup_printf("%s/channel/target", cfg->libDir); + cfg->nvramDir = g_strdup_printf("%s/nvram", cfg->libDir); + cfg->memoryBackingDir = g_strdup_printf("%s/ram", cfg->libDir); + } else if (privileged) { cfg->logDir = g_strdup_printf("%s/log/libvirt/qemu", LOCALSTATEDIR); cfg->swtpmLogDir = g_strdup_printf("%s/log/swtpm/libvirt/qemu", @@ -194,6 +212,16 @@ virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged) cfg->memoryBackingDir = g_strdup_printf("%s/qemu/ram", cfg->configBaseDir); cfg->swtpmStorageDir = g_strdup_printf("%s/qemu/swtpm", cfg->configBaseDir); + } + + if (privileged) { + if (!virDoesUserExist("tss") || + virGetUserID("tss", &cfg->swtpm_user) < 0) + cfg->swtpm_user = 0; /* fall back to root */ + if (!virDoesGroupExist("tss") || + virGetGroupID("tss", &cfg->swtpm_group) < 0) + cfg->swtpm_group = 0; /* fall back to root */ + } else { cfg->swtpm_user = (uid_t)-1; cfg->swtpm_group = (gid_t)-1; } @@ -206,7 +234,11 @@ virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged) * This will then be used as a fallback if the service specific * directory doesn't exist (although we don't check if this exists). */ - cfg->defaultTLSx509certdir = g_strdup(SYSCONFDIR "/pki/qemu"); + if (root == NULL) { + cfg->defaultTLSx509certdir = g_strdup(SYSCONFDIR "pki/qemu"); + } else { + cfg->defaultTLSx509certdir = g_strdup_printf("%s/etc/pki/qemu", root); + } cfg->vncListen = g_strdup(VIR_LOOPBACK_IPV4_ADDR); cfg->spiceListen = g_strdup(VIR_LOOPBACK_IPV4_ADDR); diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h index 95b33a1093..5de9d2f913 100644 --- a/src/qemu/qemu_conf.h +++ b/src/qemu/qemu_conf.h @@ -241,8 +241,9 @@ struct _virQEMUDriver { /* Atomic inc/dec only */ unsigned int nactive; - /* Immutable value */ + /* Immutable values */ bool privileged; + bool embedded; /* Immutable pointers. Caller must provide locking */ virStateInhibitCallback inhibitCallback; @@ -301,7 +302,8 @@ struct _virQEMUDriver { virHashAtomicPtr migrationErrors; }; -virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged); +virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged, + const char *root); int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg, const char *filename, diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 31fe921ee3..e51086ea5e 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -658,12 +658,6 @@ qemuStateInitialize(bool privileged, bool autostart = true; size_t i; - if (root != NULL) { - virReportError(VIR_ERR_INVALID_ARG, "%s", - _("Driver does not support embedded mode")); - return -1; - } - if (VIR_ALLOC(qemu_driver) < 0) return VIR_DRV_STATE_INIT_ERROR; @@ -680,6 +674,7 @@ qemuStateInitialize(bool privileged, qemu_driver->inhibitOpaque = opaque; qemu_driver->privileged = privileged; + qemu_driver->embedded = root != NULL; if (!(qemu_driver->domains = virDomainObjListNew())) goto error; @@ -693,7 +688,7 @@ qemuStateInitialize(bool privileged, if (privileged) qemu_driver->hostsysinfo = virSysinfoRead(); - if (!(qemu_driver->config = cfg = virQEMUDriverConfigNew(privileged))) + if (!(qemu_driver->config = cfg = virQEMUDriverConfigNew(privileged, root))) goto error; if (!(driverConf = g_strdup_printf("%s/qemu.conf", cfg->configBaseDir))) @@ -1208,10 +1203,18 @@ static virDrvOpenStatus qemuConnectOpen(virConnectPtr conn, return VIR_DRV_OPEN_ERROR; } - if (!virConnectValidateURIPath(conn->uri->path, - "qemu", - virQEMUDriverIsPrivileged(qemu_driver))) - return VIR_DRV_OPEN_ERROR; + if (qemu_driver->embedded) { + if (STRNEQ(conn->uri->path, "/embed")) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("URI must be qemu:///embed")); + return VIR_DRV_OPEN_ERROR; + } + } else { + if (!virConnectValidateURIPath(conn->uri->path, + "qemu", + virQEMUDriverIsPrivileged(qemu_driver))) + return VIR_DRV_OPEN_ERROR; + } if (virConnectOpenEnsureACL(conn) < 0) return VIR_DRV_OPEN_ERROR; @@ -22950,6 +22953,7 @@ static virHypervisorDriver qemuHypervisorDriver = { static virConnectDriver qemuConnectDriver = { .localOnly = true, .uriSchemes = (const char *[]){ "qemu", NULL }, + .embeddable = true, .hypervisorDriver = &qemuHypervisorDriver, }; diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index a588ee25f8..c812fa680c 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -6717,10 +6717,17 @@ qemuProcessLaunch(virConnectPtr conn, cfg = virQEMUDriverGetConfig(driver); - if ((flags & VIR_QEMU_PROCESS_START_AUTODESTROY) && !conn) { - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("Domain autodestroy requires a connection handle")); - return -1; + if (flags & VIR_QEMU_PROCESS_START_AUTODESTROY) { + if (!conn) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("Domain autodestroy requires a connection handle")); + return -1; + } + if (driver->embedded) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("Domain autodestroy not supported for embedded drivers yet")); + return -1; + } } hookData.vm = vm; diff --git a/tests/domaincapstest.c b/tests/domaincapstest.c index c6700f7e78..16a37b37fe 100644 --- a/tests/domaincapstest.c +++ b/tests/domaincapstest.c @@ -373,7 +373,7 @@ mymain(void) #endif #if WITH_QEMU - virQEMUDriverConfigPtr cfg = virQEMUDriverConfigNew(false); + virQEMUDriverConfigPtr cfg = virQEMUDriverConfigNew(false, ""); if (!cfg) return EXIT_FAILURE; diff --git a/tests/testutilsqemu.c b/tests/testutilsqemu.c index 7b9e427463..3a21dfac71 100644 --- a/tests/testutilsqemu.c +++ b/tests/testutilsqemu.c @@ -694,7 +694,7 @@ int qemuTestDriverInit(virQEMUDriver *driver) if (virMutexInit(&driver->lock) < 0) return -1; - driver->config = virQEMUDriverConfigNew(false); + driver->config = virQEMUDriverConfigNew(false, ""); if (!driver->config) goto error; -- 2.23.0

The previous "QEMU shim" proof of concept was taking an approach of only caring about initial spawning of the QEMU process. It was then registered with the libvirtd daemon who took over management of it. The intent was that later libvirtd would be refactored so that the shim retained control over the QEMU monitor and libvirt just forwarded APIs to each shim as needed. This forwarding of APIs would require quite alot of significant refactoring of libvirtd to achieve. This impl thus takes a quite different approach, explicitly deciding to keep the VMs completely separate from those seen & managed by libvirtd. Instead it uses the new "qemu:///embed" URI scheme to embed the entire QEMU driver in the shim, running with a custom root directory. Once the driver is initialization, the shim starts a VM and then waits to shutdown automatically when QEMU shuts down, or should kill QEMU if it is terminated itself. This ought to use the AUTO_DESTROY feature but that is not yet available in embedded mode, so we rely on installing a few signal handlers to gracefully kill QEMU. This isn't reliable if we crash of course, but you can restart with the same root dir. Note this program does not expose any way to manage the QEMU process, since there's no RPC interface enabled. It merely starts the VM and cleans up when the guest shuts down at the end. This program is installed to /usr/bin/virt-qemu-run enabling direct use by end users. Most use cases will probably want to integrate the concept directly into their respective application codebases. This standalone binary serves as a nice demo though, and also provides a way to measure performance of the startup process quite simply. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- build-aux/syntax-check.mk | 2 +- libvirt.spec.in | 2 + src/Makefile.am | 9 ++ src/qemu/Makefile.inc.am | 26 ++++ src/qemu/qemu_shim.c | 313 ++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_shim.pod | 94 ++++++++++++ 6 files changed, 445 insertions(+), 1 deletion(-) create mode 100644 src/qemu/qemu_shim.c create mode 100644 src/qemu/qemu_shim.pod diff --git a/build-aux/syntax-check.mk b/build-aux/syntax-check.mk index 94e4945323..627734fc55 100644 --- a/build-aux/syntax-check.mk +++ b/build-aux/syntax-check.mk @@ -2340,7 +2340,7 @@ exclude_file_name_regexp--sc_prohibit_devname = \ ^(tools/virsh.pod|build-aux/syntax-check\.mk|docs/.*)$$ exclude_file_name_regexp--sc_prohibit_virXXXFree = \ - ^(docs/|tests/|examples/|tools/|build-aux/syntax-check\.mk|src/test/test_driver.c|src/libvirt_public.syms|include/libvirt/libvirt-(domain|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).h|src/libvirt-(domain|qemu|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).c$$) + ^(docs/|tests/|examples/|tools/|build-aux/syntax-check\.mk|src/test/test_driver.c|src/libvirt_public.syms|include/libvirt/libvirt-(domain|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).h|src/libvirt-(domain|qemu|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).c|src/qemu/qemu_shim.c$$) exclude_file_name_regexp--sc_prohibit_sysconf_pagesize = \ ^(build-aux/syntax-check\.mk|src/util/virutil\.c)$$ diff --git a/libvirt.spec.in b/libvirt.spec.in index c7fac104d9..886c7b73d5 100644 --- a/libvirt.spec.in +++ b/libvirt.spec.in @@ -1757,6 +1757,8 @@ exit 0 %{_libdir}/%{name}/connection-driver/libvirt_driver_qemu.so %dir %attr(0711, root, root) %{_localstatedir}/lib/libvirt/swtpm/ %dir %attr(0711, root, root) %{_localstatedir}/log/swtpm/libvirt/qemu/ +%{_bindir}/virt-qemu-run +%{_mandir}/man1/virt-qemu-run.1* %endif %if %{with_lxc} diff --git a/src/Makefile.am b/src/Makefile.am index 696e64c52e..f86ba3fe3d 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -90,6 +90,8 @@ SYSTEMD_UNIT_FILES = SYSTEMD_UNIT_FILES_IN = SYSCONF_FILES = sbin_PROGRAMS = +bin_PROGRAMS = +man1_MANS = man8_MANS = DRIVER_SOURCES = man7_MANS = @@ -659,6 +661,13 @@ endif WITH_LIBVIRTD < $< > $@-t && \ mv $@-t $@ +%.1: %.1.in $(top_srcdir)/configure.ac + $(AM_V_GEN)sed \ + -e 's|[@]sysconfdir[@]|$(sysconfdir)|g' \ + -e 's|[@]runstatedir[@]|$(runstatedir)|g' \ + < $< > $@-t && \ + mv $@-t $@ + CLEANFILES += \ $(man8_MANS) \ $(MANINFILES) diff --git a/src/qemu/Makefile.inc.am b/src/qemu/Makefile.inc.am index bf30f8a3c5..d41853ac9e 100644 --- a/src/qemu/Makefile.inc.am +++ b/src/qemu/Makefile.inc.am @@ -231,3 +231,29 @@ EXTRA_DIST += \ qemu/THREADS.txt \ libvirt_qemu_probes.d \ $(NULL) + +QEMU_SHIM_SOURCES = qemu/qemu_shim.c +QEMU_SHIM_POD = qemu/qemu_shim.pod + +EXTRA_DIST += $(QEMU_SHIM_SOURCES) $(QEMU_SHIM_POD) + +if WITH_QEMU +bin_PROGRAMS += virt-qemu-run + +man1_MANS += virt-qemu-run.1 + +virt_qemu_run_SOURCES = $(QEMU_SHIM_SOURCES) + +virt_qemu_run_LDADD = libvirt.la +virt_qemu_run_LDFLAGS = -Wl,--export-dynamic +endif WITH_QEMU + +virt-qemu-run.1.in: qemu/qemu_shim.pod + $(AM_V_GEN)$(POD2MAN) $< $@-t1 && \ + if grep 'POD ERROR' $@-t1; then rm $@-t1; exit 1; fi && \ + sed \ + -e 's|SYSCONFDIR|\@sysconfdir\@|g' \ + -e 's|LOCALSTATEDIR|\@localstatedir\@|g' \ + < $@-t1 > $@-t2 && \ + rm -f $@-t1 && \ + mv $@-t2 $@ diff --git a/src/qemu/qemu_shim.c b/src/qemu/qemu_shim.c new file mode 100644 index 0000000000..10f9682143 --- /dev/null +++ b/src/qemu/qemu_shim.c @@ -0,0 +1,313 @@ +/* + * qemu_shim.c: standalone binary for running QEMU instances + * + * Copyright (C) 2019 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see + * <http://www.gnu.org/licenses/>;. + */ + +#include <config.h> + +#include <stdio.h> +#include <stdbool.h> + +#include "virfile.h" +#include "virstring.h" +#include "virgettext.h" + +#define VIR_FROM_THIS VIR_FROM_QEMU + +static bool eventQuitFlag; +static int eventQuitFD = -1; +static virDomainPtr dom; + +static void * +qemuShimEventLoop(void *opaque G_GNUC_UNUSED) +{ + while (!eventQuitFlag) + virEventRunDefaultImpl(); + + return NULL; +} + +/* Runs in event loop thread context */ +static void +qemuShimEventLoopStop(int watch G_GNUC_UNUSED, + int fd G_GNUC_UNUSED, + int event G_GNUC_UNUSED, + void *opaque G_GNUC_UNUSED) +{ + char c; + ignore_value(read(fd, &c, 1)); + eventQuitFlag = true; +} + +/* Runs in event loop thread context */ +static int +qemuShimDomShutdown(virConnectPtr econn G_GNUC_UNUSED, + virDomainPtr edom G_GNUC_UNUSED, + int event, + int detail G_GNUC_UNUSED, + void *opaque G_GNUC_UNUSED) +{ + if (event == VIR_DOMAIN_EVENT_STOPPED) + eventQuitFlag = true; + + return 0; +} + +/* Runs in unknown thread context */ +static void +qemuShimSigShutdown(int sig G_GNUC_UNUSED) +{ + if (dom) + virDomainDestroy(dom); + ignore_value(safewrite(eventQuitFD, "c", 1)); +} + +static void +qemuShimQuench(void *userData G_GNUC_UNUSED, + virErrorPtr error G_GNUC_UNUSED) +{ +} + +int main(int argc, char **argv) +{ + GThread *eventLoopThread = NULL; + virConnectPtr conn = NULL; + virConnectPtr sconn = NULL; + g_autofree char *xml = NULL; + g_autofree char *uri = NULL; + g_autofree char *suri = NULL; + char *root = NULL; + bool tmproot = false; + int ret = 1; + g_autoptr(GError) error = NULL; + g_auto(GStrv) secrets = NULL; + bool verbose = false; + GStrv tmpsecrets; + GOptionContext *ctx; + GOptionEntry entries[] = { + { "secret", 's', 0, G_OPTION_ARG_STRING_ARRAY, &secrets, "Load secret file", "SECRET-XML-FILE,SECRET-VALUE-FILE" }, + { "root", 'r', 0, G_OPTION_ARG_STRING, &root, "Root directory", "DIR"}, + { "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose, "Verbose output", NULL }, + { NULL } + }; + int quitfd[2] = {-1, -1}; + long long start = g_get_monotonic_time(); + +#define deltams() ((long long)g_get_monotonic_time() - start) + + ctx = g_option_context_new("- run a standalone QEMU process"); + g_option_context_add_main_entries(ctx, entries, PACKAGE); + if (!g_option_context_parse(ctx, &argc, &argv, &error)) { + g_printerr("%s: option parsing failed: %s\n", + argv[0], error->message); + return 1; + } + if (argc != 2) { + g_autofree char *help = g_option_context_get_help(ctx, TRUE, NULL); + g_printerr("%s", help); + return 1; + } + + if (verbose) + g_printerr("%s: %lld: initializing libvirt\n", + argv[0], deltams()); + + if (virInitialize() < 0) { + g_printerr("%s: cannot initialize libvirt\n", argv[0]); + return 1; + } + if (virGettextInitialize() < 0) { + g_printerr("%s: cannot initialize libvirt translations\n", argv[0]); + return 1; + } + + virSetErrorFunc(NULL, qemuShimQuench); + + if (verbose) + g_printerr("%s: %lld: initializing signal handlers\n", + argv[0], deltams()); + + signal(SIGTERM, qemuShimSigShutdown); + signal(SIGINT, qemuShimSigShutdown); + signal(SIGQUIT, qemuShimSigShutdown); + signal(SIGHUP, qemuShimSigShutdown); + + if (root == NULL) { + if (!(root = g_dir_make_tmp("libvirt-qemu-shim-XXXXXX", &error))) { + g_printerr("%s: cannot create temporary dir: %s\n", + argv[0], error->message); + return 1; + } + tmproot = true; + } + + virFileActivateDirOverrideForProg(argv[0]); + + if (verbose) + g_printerr("%s: %lld: preparing event loop thread\n", + argv[0], deltams()); + virEventRegisterDefaultImpl(); + + if (pipe(quitfd) < 0) { + g_printerr("%s: cannot create event loop pipe: %s", + argv[0], g_strerror(errno)); + goto cleanup; + } + + if (virEventAddHandle(quitfd[0], VIR_EVENT_HANDLE_READABLE, qemuShimEventLoopStop, NULL, NULL) < 0) { + VIR_FORCE_CLOSE(quitfd[0]); + VIR_FORCE_CLOSE(quitfd[1]); + quitfd[0] = quitfd[1] = -1; + g_printerr("%s: cannot register event loop handle: %s", + argv[0], virGetLastErrorMessage()); + goto cleanup; + } + eventQuitFD = quitfd[1]; + + eventLoopThread = g_thread_new("event-loop", qemuShimEventLoop, NULL); + + if (secrets && *secrets) { + suri = g_strdup_printf("secret:///embed?root=%s", root); + + if (verbose) + g_printerr("%s: %lld: opening %s\n", + argv[0], deltams(), suri); + + sconn = virConnectOpen(suri); + if (!sconn) { + g_printerr("%s: cannot open %s: %s\n", + argv[0], suri, virGetLastErrorMessage()); + goto cleanup; + } + + tmpsecrets = secrets; + while (tmpsecrets && *tmpsecrets) { + g_auto(GStrv) bits = g_strsplit(*tmpsecrets, ",", 2); + g_autofree char *sxml = NULL; + g_autofree char *value = NULL; + virSecretPtr sec; + size_t nvalue; + + if (!bits || bits[0] == NULL || bits[1] == NULL) { + g_printerr("%s: expected a pair of filenames for --secret argument\n", + argv[0]); + goto cleanup; + } + + if (verbose) + g_printerr("%s: %lld: loading secret %s and %s\n", + argv[0], deltams(), bits[0], bits[1]); + + if (!g_file_get_contents(bits[0], &sxml, NULL, &error)) { + g_printerr("%s: cannot read secret XML %s: %s\n", + argv[0], bits[0], error->message); + goto cleanup; + } + + if (!g_file_get_contents(bits[1], &value, &nvalue, &error)) { + g_printerr("%s: cannot read secret value %s: %s\n", + argv[0], bits[1], error->message); + goto cleanup; + } + + if (!(sec = virSecretDefineXML(sconn, sxml, 0))) { + g_printerr("%s: cannot define secret %s: %s\n", + argv[0], bits[0], virGetLastErrorMessage()); + goto cleanup; + } + + if (virSecretSetValue(sec, (unsigned char *)value, nvalue, 0) < 0) { + virSecretFree(sec); + g_printerr("%s: cannot set value for secret %s: %s\n", + argv[0], bits[0], virGetLastErrorMessage()); + goto cleanup; + } + virSecretFree(sec); + + tmpsecrets++; + } + } + + uri = g_strdup_printf("qemu:///embed?root=%s", root); + + if (verbose) + g_printerr("%s: %lld: opening %s\n", + argv[0], deltams(), uri); + + conn = virConnectOpen(uri); + if (!conn) { + g_printerr("%s: cannot open %s: %s\n", + argv[0], uri, virGetLastErrorMessage()); + goto cleanup; + } + + if (virConnectDomainEventRegisterAny( + conn, dom, VIR_DOMAIN_EVENT_ID_LIFECYCLE, + VIR_DOMAIN_EVENT_CALLBACK(qemuShimDomShutdown), + NULL, NULL) < 0) { + g_printerr("%s: cannot regiser for lifecycle events: %s\n", + argv[0], virGetLastErrorMessage()); + goto cleanup; + } + + if (verbose) + g_printerr("%s: %lld: starting guest %s\n", + argv[0], deltams(), argv[1]); + + if (!g_file_get_contents(argv[1], &xml, NULL, &error)) { + g_printerr("%s: cannot read %s: %s\n", + argv[0], argv[1], error->message); + goto cleanup; + } + + dom = virDomainCreateXML(conn, xml, 0); + if (!dom) { + g_printerr("%s: cannot start VM: %s\n", + argv[0], virGetLastErrorMessage()); + goto cleanup; + } + if (verbose) + g_printerr("%s: %lld: guest running, Ctrl-C to stop\n", + argv[0], deltams()); + + ret = 0; + + cleanup: + if (ret != 0 && eventQuitFD != -1) + ignore_value(safewrite(eventQuitFD, "c", 1)); + + if (eventLoopThread != NULL && (ret == 0 || eventQuitFD != -1)) + g_thread_join(eventLoopThread); + + VIR_FORCE_CLOSE(quitfd[0]); + VIR_FORCE_CLOSE(quitfd[1]); + + if (dom != NULL) + virDomainFree(dom); + if (sconn != NULL) + virConnectClose(sconn); + if (conn != NULL) + virConnectClose(conn); + if (tmproot) + virFileDeleteTree(root); + + if (verbose) + g_printerr("%s: %lld: cleaned up, exiting\n", + argv[0], deltams()); + return ret; +} diff --git a/src/qemu/qemu_shim.pod b/src/qemu/qemu_shim.pod new file mode 100644 index 0000000000..eb17fa0ac7 --- /dev/null +++ b/src/qemu/qemu_shim.pod @@ -0,0 +1,94 @@ +=encoding utf8 + +=head1 NAME + +virt-qemu-run - run a standalone QEMU guest + +=head1 SYNOPSIS + +B<virt-qemu-run> [I<OPTIONS>...] [I<GUEST-XML>] + +=head1 DESCRIPTION + +This tool provides a way to run a standalone QEMU guest such that it +is completely independant of libvirtd. It makes use of the embedded +QEMU driver support to run the VM placing files under an isolated +directory tree. When the guest is run with this tool it is invisible +to libvirtd and thus also invisible to other libvirt tools such as +virsh. + +The virt-qemu-run program will run the QEMU virtual machine, and then +block until the guest OS shuts down, at which point it will exit. + +If the virt-qemu-run program is interrupted (eg Ctrl-C) it will +immediately terminate the virtual machine without giving the guest +OS any opportunity to gracefully shutdown. + +=head1 OPTIONS + +=over 4 + +=item C<GUEST-XML> + +The full path to the XML file describing the guest virtual machine +to be booted. + +=item C<-h>, C<--help> + +Display the command line help + +=item C<-v>, C<--verbose> + +Display verbose information about startup + +=item C<-r DIR>, C<--root=DIR> + +Specify the root directory to use for storing state associated with +the virtual machine. The caller is responsible for deleting this +directory when it is no longer required. + +If this parameter is omitted, then a random temporary directory +will be created, and its contents be automaticlaly deleted at +VM shutdown. + +=item C<-s XML-FILE,VALUE-FILE> C<--secret=XML-FILE,VALUE-FILE> + +Specify a secret to be loaded into the secret driver. The C<XML-FILE> +is a path to the XML description of the secret, whose UUID should +match a secret referenced in the guest domain XML. The C<VALUE-FILE> +is a path containing the raw value of the secret. + +=back + +=head1 EXIT STATUS + +Upon successful shutdown, an exit status of 0 will be set. Upon +failure a non-zero status will be set. + +=head1 AUTHOR + +Daniel P. Berrangé + +=head1 BUGS + +Report any bugs discovered to the libvirt community via the +mailing list L<https://libvirt.org/contact.html> or bug tracker +L<https://libvirt.org/bugs.html>. +Alternatively report bugs to your software distributor / vendor. + +=head1 COPYRIGHT + +Copyright (C) 2019 by Red Hat, Inc. + +=head1 LICENSE + +virt-run-qemu is distributed under the terms of the GNU LGPL v2+. +This is free software; see the source for copying conditions. There +is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR +PURPOSE + +=head1 SEE ALSO + +L<virsh(1)> + +=cut -- 2.23.0