[libvirt] [PATCH 21/23] Add support for hotplug/unplug of host misc devices in LXC

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; Wire up the attach/detach device drivers in LXC to support the hotplug/unplug of host misc devices. Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- src/lxc/lxc_driver.c | 194 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 194 insertions(+) diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c index 27ee3d7..17445a7 100644 --- a/src/lxc/lxc_driver.c +++ b/src/lxc/lxc_driver.c @@ -3474,6 +3474,123 @@ cleanup: static int +lxcDomainAttachDeviceHostdevMiscLive(virLXCDriverPtr driver, + virDomainObjPtr vm, + virDomainDeviceDefPtr dev) +{ + virLXCDomainObjPrivatePtr priv = vm->privateData; + virDomainHostdevDefPtr def = dev->data.hostdev; + virCgroupPtr group = NULL; + int ret = -1; + char *dst; + char *vroot; + struct stat sb; + bool created = false; + mode_t mode = 0; + + if (!priv->initpid) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("Cannot attach disk until init PID is known")); + goto cleanup; + } + + if (!def->source.caps.u.misc.chardev) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("Missing storage block path")); + goto cleanup; + } + + if (virDomainHostdevFind(vm->def, def, NULL) >= 0) { + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("host device already exists")); + return -1; + } + + if (stat(def->source.caps.u.misc.chardev, &sb) < 0) { + virReportSystemError(errno, + _("Unable to access %s"), + def->source.caps.u.misc.chardev); + goto cleanup; + } + + if (!S_ISCHR(sb.st_mode)) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Hostdev source %s must be a block device"), + def->source.caps.u.misc.chardev); + goto cleanup; + } + + if (virAsprintf(&vroot, "/proc/%llu/root", + (unsigned long long)priv->initpid) < 0) { + virReportOOMError(); + goto cleanup; + } + + if (virAsprintf(&dst, "%s/%s", + vroot, + def->source.caps.u.misc.chardev) < 0) { + virReportOOMError(); + goto cleanup; + } + + if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs+1) < 0) { + virReportOOMError(); + goto cleanup; + } + + mode = 0700 | S_IFCHR; + + VIR_DEBUG("Creating dev %s (%d,%d)", + def->source.caps.u.misc.chardev, + major(sb.st_rdev), minor(sb.st_rdev)); + if (mknod(dst, mode, sb.st_rdev) < 0) { + virReportSystemError(errno, + _("Unable to create device %s"), + dst); + goto cleanup; + } + created = true; + + if (virSecurityManagerSetHostdevLabel(driver->securityManager, + vm->def, def, vroot) < 0) + goto cleanup; + + if (!lxcCgroupControllerActive(driver, VIR_CGROUP_CONTROLLER_DEVICES)) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("devices cgroup isn't mounted")); + goto cleanup; + } + + if (virCgroupForDomain(driver->cgroup, vm->def->name, &group, 0) != 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("cannot find cgroup for domain %s"), vm->def->name); + goto cleanup; + } + + if (virCgroupAllowDevicePath(group, def->source.caps.u.misc.chardev, + VIR_CGROUP_DEVICE_RW | + VIR_CGROUP_DEVICE_MKNOD) != 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("cannot allow device %s for domain %s"), + def->source.caps.u.misc.chardev, vm->def->name); + goto cleanup; + } + + vm->def->hostdevs[vm->def->nhostdevs++] = def; + + ret = 0; + +cleanup: + virDomainAuditHostdev(vm, def, "attach", ret == 0); + if (group) + virCgroupFree(&group); + if (dst && created && ret < 0) + unlink(dst); + return ret; +} + + +static int lxcDomainAttachDeviceHostdevSubsysLive(virLXCDriverPtr driver, virDomainObjPtr vm, virDomainDeviceDefPtr dev) @@ -3500,6 +3617,9 @@ lxcDomainAttachDeviceHostdevCapsLive(virLXCDriverPtr driver, case VIR_DOMAIN_HOSTDEV_CAPS_TYPE_STORAGE: return lxcDomainAttachDeviceHostdevStorageLive(driver, vm, dev); + case VIR_DOMAIN_HOSTDEV_CAPS_TYPE_MISC: + return lxcDomainAttachDeviceHostdevMiscLive(driver, vm, dev); + default: virReportError(VIR_ERR_CONFIG_UNSUPPORTED, _("Unsupported host device type %s"), @@ -3875,6 +3995,77 @@ cleanup: static int +lxcDomainDetachDeviceHostdevMiscLive(virLXCDriverPtr driver, + virDomainObjPtr vm, + virDomainDeviceDefPtr dev) +{ + virLXCDomainObjPrivatePtr priv = vm->privateData; + virDomainHostdevDefPtr def = NULL; + virCgroupPtr group = NULL; + int i, ret = -1; + char *dst = NULL; + + if (!priv->initpid) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("Cannot attach disk until init PID is known")); + goto cleanup; + } + + if ((i = virDomainHostdevFind(vm->def, + dev->data.hostdev, + &def)) < 0) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("hostdev %s not found"), + dev->data.hostdev->source.caps.u.misc.chardev); + goto cleanup; + } + + if (virAsprintf(&dst, "/proc/%llu/root/%s", + (unsigned long long)priv->initpid, + def->source.caps.u.misc.chardev) < 0) { + virReportOOMError(); + goto cleanup; + } + + if (!lxcCgroupControllerActive(driver, VIR_CGROUP_CONTROLLER_DEVICES)) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("devices cgroup isn't mounted")); + goto cleanup; + } + + if (virCgroupForDomain(driver->cgroup, vm->def->name, &group, 0) != 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("cannot find cgroup for domain %s"), vm->def->name); + goto cleanup; + } + + VIR_DEBUG("Unlinking %s", dst); + if (unlink(dst) < 0 && errno != ENOENT) { + virDomainAuditHostdev(vm, def, "detach", false); + virReportSystemError(errno, + _("Unable to remove device %s"), dst); + goto cleanup; + } + virDomainAuditHostdev(vm, def, "detach", true); + + if (virCgroupDenyDevicePath(group, def->source.caps.u.misc.chardev, VIR_CGROUP_DEVICE_RWM) != 0) + VIR_WARN("cannot deny device %s for domain %s", + def->source.caps.u.misc.chardev, vm->def->name); + + virDomainHostdevRemove(vm->def, i); + virDomainHostdevDefFree(def); + + ret = 0; + +cleanup: + VIR_FREE(dst); + if (group) + virCgroupFree(&group); + return ret; +} + + +static int lxcDomainDetachDeviceHostdevSubsysLive(virLXCDriverPtr driver, virDomainObjPtr vm, virDomainDeviceDefPtr dev) @@ -3901,6 +4092,9 @@ lxcDomainDetachDeviceHostdevCapsLive(virLXCDriverPtr driver, case VIR_DOMAIN_HOSTDEV_CAPS_TYPE_STORAGE: return lxcDomainDetachDeviceHostdevStorageLive(driver, vm, dev); + case VIR_DOMAIN_HOSTDEV_CAPS_TYPE_MISC: + return lxcDomainDetachDeviceHostdevMiscLive(driver, vm, dev); + default: virReportError(VIR_ERR_CONFIG_UNSUPPORTED, _("Unsupported host device type %s"), -- 1.8.0.1