lock_driver_lockd.c

/*
 * lock_driver_lockd.c: A lock driver which locks nothing
 *
 * Copyright (C) 2010-2011 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 "lock_driver.h"
#include "virconf.h"
#include "viralloc.h"
#include "virlog.h"
#include "viruuid.h"
#include "virutil.h"
#include "virfile.h"
#include "virterror_internal.h"
#include "rpc/virnetclient.h"
#include "lock_protocol.h"
#include "configmake.h"
#include "sha256.h"

#define VIR_FROM_THIS VIR_FROM_LOCKING

#define virLockError(code, ...)                                     \
    virReportErrorHelper(VIR_FROM_THIS, code, __FILE__,             \
                         __FUNCTION__, __LINE__, __VA_ARGS__)

typedef struct _virLockManagerLockDaemonPrivate virLockManagerLockDaemonPrivate;
typedef virLockManagerLockDaemonPrivate *virLockManagerLockDaemonPrivatePtr;

typedef struct _virLockManagerLockDaemonResource virLockManagerLockDaemonResource;
typedef virLockManagerLockDaemonResource *virLockManagerLockDaemonResourcePtr;

typedef struct _virLockManagerLockDaemonDriver virLockManagerLockDaemonDriver;
typedef virLockManagerLockDaemonDriver *virLockManagerLockDaemonDriverPtr;

struct _virLockManagerLockDaemonResource {
    char *lockspace;
    char *name;
    unsigned int flags;
};

struct _virLockManagerLockDaemonPrivate {
    unsigned char uuid[VIR_UUID_BUFLEN];
    char *name;
    int id;
    pid_t pid;

    size_t nresources;
    virLockManagerLockDaemonResourcePtr resources;

    bool hasRWDisks;
};


struct _virLockManagerLockDaemonDriver {
    bool autoDiskLease;
    bool requireLeaseForDisks;

    char *fileLockSpaceDir;
    char *lvmLockSpaceDir;
    char *scsiLockSpaceDir;
};

static virLockManagerLockDaemonDriverPtr driver = NULL;

#define VIRTLOCKD_PATH SBINDIR "/virtlockd"

static const char *
virLockManagerLockDaemonFindDaemon(void)
{
    const char *customDaemon = getenv("VIRTLOCKD_PATH");

    if (customDaemon)
        return customDaemon;

    if (virFileIsExecutable(VIRTLOCKD_PATH))
        return VIRTLOCKD_PATH;

    return NULL;
}

static int virLockManagerLockDaemonLoadConfig(const char *configFile)
{
    virConfPtr conf;
    virConfValuePtr p;

    if (access(configFile, R_OK) == -1) {
        if (errno != ENOENT) {
            virReportSystemError(errno,
                                 _("Unable to access config file %s"),
                                 configFile);
            return -1;
        }
        return 0;
    }

    if (!(conf = virConfReadFile(configFile, 0)))
        return -1;

#define CHECK_TYPE(name,typ) if (p && p->type != (typ)) {               \
        virReportError(VIR_ERR_INTERNAL_ERROR,                          \
                       "%s: %s: expected type " #typ,                   \
                       configFile, (name));                             \
        virConfFree(conf);                                              \
        return -1;                                                      \
    }

    p = virConfGetValue(conf, "auto_disk_leases");
    CHECK_TYPE("auto_disk_leases", VIR_CONF_LONG);
    if (p) driver->autoDiskLease = p->l;

    p = virConfGetValue(conf, "file_lockspace_dir");
    CHECK_TYPE("file_lockspace_dir", VIR_CONF_STRING);
    if (p && p->str) {
        VIR_FREE(driver->fileLockSpaceDir);
        if (!(driver->fileLockSpaceDir = strdup(p->str))) {
            virReportOOMError();
            virConfFree(conf);
            return -1;
        }
    }

    p = virConfGetValue(conf, "lvm_lockspace_dir");
    CHECK_TYPE("lvm_lockspace_dir", VIR_CONF_STRING);
    if (p && p->str) {
        VIR_FREE(driver->lvmLockSpaceDir);
        if (!(driver->lvmLockSpaceDir = strdup(p->str))) {
            virReportOOMError();
            virConfFree(conf);
            return -1;
        }
    }

    p = virConfGetValue(conf, "scsi_lockspace_dir");
    CHECK_TYPE("scsi_lockspace_dir", VIR_CONF_STRING);
    if (p && p->str) {
        VIR_FREE(driver->scsiLockSpaceDir);
        if (!(driver->scsiLockSpaceDir = strdup(p->str))) {
            virReportOOMError();
            virConfFree(conf);
            return -1;
        }
    }

    p = virConfGetValue(conf, "require_lease_for_disks");
    CHECK_TYPE("require_lease_for_disks", VIR_CONF_LONG);
    if (p)
        driver->requireLeaseForDisks = p->l;
    else
        driver->requireLeaseForDisks = !driver->autoDiskLease;

    virConfFree(conf);
    return 0;
}


static char *virLockManagerLockDaemonPath(bool privileged)
{
    char *path;
    if (privileged) {
        if (!(path = strdup(LOCALSTATEDIR "/run/libvirt/virtlockd-sock"))) {
            virReportOOMError();
            return NULL;
        }
    } else {
        char *rundir = NULL;

        if (!(rundir = virGetUserRuntimeDirectory()))
            return NULL;

        if (virAsprintf(&path, "%s/virtlockd-sock", rundir) < 0) {
            VIR_FREE(rundir);
            virReportOOMError();
            return NULL;
        }

    }
    return path;
}


static int
virLockManagerLockDaemonConnectionRegister(virLockManagerPtr lock,
                                           virNetClientPtr client,
                                           virNetClientProgramPtr program,
                                           int *counter)
{
    virLockManagerLockDaemonPrivatePtr priv = lock->privateData;
    virLockSpaceProtocolRegisterArgs args;
    int rv = -1;

    memset(&args, 0, sizeof(args));

    args.flags = 0;
    memcpy(args.owner.uuid, priv->uuid, VIR_UUID_BUFLEN);
    args.owner.name = priv->name;
    args.owner.id = priv->id;
    args.owner.pid = priv->pid;

    if (virNetClientProgramCall(program,
                                client,
                                (*counter)++,
                                VIR_LOCK_SPACE_PROTOCOL_PROC_REGISTER,
                                0, NULL, NULL, NULL,
                                (xdrproc_t)xdr_virLockSpaceProtocolRegisterArgs, (char*)&args,
                                (xdrproc_t)xdr_void, NULL) < 0)
        goto cleanup;

    rv = 0;

cleanup:
    return rv;
}


static int
virLockManagerLockDaemonConnectionRestrict(virLockManagerPtr lock ATTRIBUTE_UNUSED,
                                           virNetClientPtr client,
                                           virNetClientProgramPtr program,
                                           int *counter)
{
    virLockSpaceProtocolRestrictArgs args;
    int rv = -1;

    memset(&args, 0, sizeof(args));

    args.flags = 0;

    if (virNetClientProgramCall(program,
                                client,
                                (*counter)++,
                                VIR_LOCK_SPACE_PROTOCOL_PROC_RESTRICT,
                                0, NULL, NULL, NULL,
                                (xdrproc_t)xdr_virLockSpaceProtocolRestrictArgs, (char*)&args,
                                (xdrproc_t)xdr_void, NULL) < 0)
        goto cleanup;

    rv = 0;

cleanup:
    return rv;
}


static virNetClientPtr virLockManagerLockDaemonConnectionNew(bool privileged,
                                                             virNetClientProgramPtr *prog)
{
    virNetClientPtr client = NULL;
    char *lockdpath;
    const char *daemonPath = NULL;

    *prog = NULL;

    if (!(lockdpath = virLockManagerLockDaemonPath(privileged)))
        goto error;

    if (!privileged)
        daemonPath = virLockManagerLockDaemonFindDaemon();

    if (!(client = virNetClientNewUNIX(lockdpath,
                                       daemonPath != NULL,
                                       daemonPath)))
        goto error;

    if (!(*prog = virNetClientProgramNew(VIR_LOCK_SPACE_PROTOCOL_PROGRAM,
                                         VIR_LOCK_SPACE_PROTOCOL_PROGRAM_VERSION,
                                         NULL,
                                         0,
                                         NULL)))
        goto error;

    if (virNetClientAddProgram(client, *prog) < 0)
        goto error;

    VIR_FREE(lockdpath);

    return client;

error:
    VIR_FREE(lockdpath);
    virNetClientClose(client);
    virObjectUnref(client);
    virObjectUnref(*prog);
    return NULL;
}


static virNetClientPtr
virLockManagerLockDaemonConnect(virLockManagerPtr lock,
                                virNetClientProgramPtr *program,
                                int *counter)
{
    virNetClientPtr client;

    if (!(client = virLockManagerLockDaemonConnectionNew(getuid() == 0, program)))
        return NULL;

    if (virLockManagerLockDaemonConnectionRegister(lock,
                                                   client,
                                                   *program,
                                                   counter) < 0)
        goto error;

    return client;

error:
    virNetClientClose(client);
    virObjectUnref(client);
    return NULL;
}


static int virLockManagerLockDaemonSetupLockspace(const char *path)
{
    virNetClientPtr client;
    virNetClientProgramPtr program = NULL;
    virLockSpaceProtocolCreateLockSpaceArgs args;
    int rv = -1;
    int counter = 0;

    memset(&args, 0, sizeof(args));
    args.path = (char*)path;

    if (!(client = virLockManagerLockDaemonConnectionNew(getuid() == 0, &program)))
        return -1;

    if (virNetClientProgramCall(program,
                                client,
                                counter++,
                                VIR_LOCK_SPACE_PROTOCOL_PROC_CREATE_LOCKSPACE,
                                0, NULL, NULL, NULL,
                                (xdrproc_t)xdr_virLockSpaceProtocolCreateLockSpaceArgs, (char*)&args,
                                (xdrproc_t)xdr_void, NULL) < 0) {
        virErrorPtr err = virGetLastError();
        if (err && err->code == VIR_ERR_OPERATION_INVALID) {
            /* The lockspace already exists */
            virResetLastError();
            rv = 0;
        } else {
            goto cleanup;
        }
    }

    rv = 0;

cleanup:
    virObjectUnref(program);
    virNetClientClose(client);
    virObjectUnref(client);
    return rv;
}


static int virLockManagerLockDaemonDeinit(void);

static int virLockManagerLockDaemonInit(unsigned int version,
                                        const char *configFile,
                                        unsigned int flags)
{
    VIR_DEBUG("version=%u configFile=%s flags=%x", version, NULLSTR(configFile), flags);

    virCheckFlags(0, -1);

    if (driver)
        return 0;

    if (VIR_ALLOC(driver) < 0) {
        virReportOOMError();
        return -1;
    }

    driver->requireLeaseForDisks = true;
    driver->autoDiskLease = true;

    if (virLockManagerLockDaemonLoadConfig(configFile) < 0)
        goto error;

    if (driver->autoDiskLease) {
        if (driver->fileLockSpaceDir &&
            virLockManagerLockDaemonSetupLockspace(driver->fileLockSpaceDir) < 0)
            goto error;

        if (driver->lvmLockSpaceDir &&
            virLockManagerLockDaemonSetupLockspace(driver->lvmLockSpaceDir) < 0)
            goto error;

        if (driver->scsiLockSpaceDir &&
            virLockManagerLockDaemonSetupLockspace(driver->scsiLockSpaceDir) < 0)
            goto error;
    }

    return 0;

error:
    virLockManagerLockDaemonDeinit();
    return -1;
}

static int virLockManagerLockDaemonDeinit(void)
{
    if (!driver)
        return 0;

    VIR_FREE(driver->fileLockSpaceDir);
    VIR_FREE(driver);

    return 0;
}

static void virLockManagerLockDaemonFree(virLockManagerPtr lock)
{
    virLockManagerLockDaemonPrivatePtr priv = lock->privateData;
    size_t i;

    if (!priv)
        return;

    lock->privateData = NULL;

    for (i = 0 ; i < priv->nresources ; i++) {
        VIR_FREE(priv->resources[i].lockspace);
        VIR_FREE(priv->resources[i].name);
    }
    VIR_FREE(priv->resources);

    VIR_FREE(priv->name);

    VIR_FREE(priv);
}


static int virLockManagerLockDaemonNew(virLockManagerPtr lock,
                                       unsigned int type,
                                       size_t nparams,
                                       virLockManagerParamPtr params,
                                       unsigned int flags)
{
    virLockManagerLockDaemonPrivatePtr priv;
    size_t i;

    virCheckFlags(VIR_LOCK_MANAGER_USES_STATE, -1);

    if (VIR_ALLOC(priv) < 0) {
        virReportOOMError();
        return -1;
    }
    lock->privateData = priv;

    switch (type) {
    case VIR_LOCK_MANAGER_OBJECT_TYPE_DOMAIN:
        for (i = 0 ; i < nparams ; i++) {
            if (STREQ(params[i].key, "uuid")) {
                memcpy(priv->uuid, params[i].value.uuid, VIR_UUID_BUFLEN);
            } else if (STREQ(params[i].key, "name")) {
                if (!(priv->name = strdup(params[i].value.str))) {
                    virReportOOMError();
                    return -1;
                }
            } else if (STREQ(params[i].key, "id")) {
                priv->id = params[i].value.i;
            } else if (STREQ(params[i].key, "pid")) {
                priv->pid = params[i].value.i;
            } else {
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Unexpected parameter %s for object"),
                               params[i].key);
            }
        }
        if (priv->id == 0) {
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("Missing ID parameter for domain object"));
            return -1;
        }
        if (priv->pid == 0) {
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("Missing PID parameter for domain object"));
            return -1;
        }
        if (!priv->name) {
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("Missing name parameter for domain object"));
            return -1;
        }
        if (!virUUIDIsValid(priv->uuid)) {
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("Missing UUID parameter for domain object"));
            return -1;
        }
        break;

    default:
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Unknown lock manager object type %d"),
                       type);
        return -1;
    }

    return 0;
}


static const char hex[] = { '0', '1', '2', '3', '4', '5', '6', '7',
                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

static char *virLockManagerLockDaemonDiskLeaseName(const char *path)
{
    unsigned char buf[SHA256_DIGEST_SIZE];
    char *ret;
    int i;

    if (!(sha256_buffer(path, strlen(path), buf))) {
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("Unable to compute sha256 checksum"));
        return NULL;
    }

    if (VIR_ALLOC_N(ret, (SHA256_DIGEST_SIZE * 2) + 1) < 0) {
        virReportOOMError();
        return NULL;
    }

    for (i = 0 ; i < SHA256_DIGEST_SIZE ; i++) {
        ret[i*2] = hex[(buf[i] >> 4) & 0xf];
        ret[(i*2)+1] = hex[buf[i] & 0xf];
    }
    ret[(SHA256_DIGEST_SIZE * 2) + 1] = '\0';

    return ret;
}


static int virLockManagerLockDaemonAddResource(virLockManagerPtr lock,
                                               unsigned int type,
                                               const char *name,
                                               size_t nparams,
                                               virLockManagerParamPtr params,
                                               unsigned int flags)
{
    virLockManagerLockDaemonPrivatePtr priv = lock->privateData;
    char *newName = NULL;
    char *newLockspace = NULL;
    bool autoCreate = false;

    virCheckFlags(VIR_LOCK_MANAGER_RESOURCE_READONLY |
                  VIR_LOCK_MANAGER_RESOURCE_SHARED, -1);

    if (flags & VIR_LOCK_MANAGER_RESOURCE_READONLY)
        return 0;

    switch (type) {
    case VIR_LOCK_MANAGER_RESOURCE_TYPE_DISK:
        if (params || nparams) {
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("Unexpected parameters for disk resource"));
            return -1;
        }
        if (!driver->autoDiskLease) {
            if (!(flags & (VIR_LOCK_MANAGER_RESOURCE_SHARED |
                           VIR_LOCK_MANAGER_RESOURCE_READONLY)))
                priv->hasRWDisks = true;
            return 0;
        }

        /* XXX we should somehow pass in TYPE=BLOCK info
         * from the domain_lock code, instead of assuming /dev
         */
        if (STRPREFIX(name, "/dev") &&
            driver->lvmLockSpaceDir) {
            VIR_DEBUG("Trying to find an LVM UUID for %s", name);
            if (virStorageFileGetLVMKey(name, &newName) < 0)
                goto error;

            if (newName) {
                VIR_DEBUG("Got an LVM UUID %s for %s", newName, name);
                if (!(newLockspace = strdup(driver->lvmLockSpaceDir)))
                    goto no_memory;
                autoCreate = true;
                break;
            }
            virResetLastError();
            /* Fallback to generic non-block code */
        }

        if (STRPREFIX(name, "/dev") &&
            driver->scsiLockSpaceDir) {
            VIR_DEBUG("Trying to find an SCSI ID for %s", name);
            if (virStorageFileGetSCSIKey(name, &newName) < 0)
                goto error;

            if (newName) {
                VIR_DEBUG("Got an SCSI ID %s for %s", newName, name);
                if (!(newLockspace = strdup(driver->scsiLockSpaceDir)))
                    goto no_memory;
                autoCreate = true;
                break;
            }
            virResetLastError();
            /* Fallback to generic non-block code */
        }

        if (driver->fileLockSpaceDir) {
            if (!(newLockspace = strdup(driver->fileLockSpaceDir)))
                goto no_memory;
            if (!(newName = virLockManagerLockDaemonDiskLeaseName(name)))
                goto no_memory;
            autoCreate = true;
            VIR_DEBUG("Using indirect lease %s for %s", newName, name);
        } else {
            if (!(newLockspace = strdup("")))
                goto no_memory;
            if (!(newName = strdup(name)))
                goto no_memory;
            VIR_DEBUG("Using direct lease for %s", name);
        }

        break;
    case VIR_LOCK_MANAGER_RESOURCE_TYPE_LEASE: {
        size_t i;
        char *path = NULL;
        char *lockspace = NULL;
        for (i = 0 ; i < nparams ; i++) {
            if (STREQ(params[i].key, "offset")) {
                if (params[i].value.ul != 0) {
                    virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                                   _("Offset must be zero for this lock manager"));
                    return -1;
                }
            } else if (STREQ(params[i].key, "lockspace")) {
                lockspace = params[i].value.str;
            } else if (STREQ(params[i].key, "path")) {
                path = params[i].value.str;
            } else {
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Unexpected parameter %s for lease resource"),
                               params[i].key);
                return -1;
            }
        }
        if (!path || !lockspace) {
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("Missing path or lockspace for lease resource"));
            return -1;
        }
        if (virAsprintf(&newLockspace, "%s/%s",
                        path, lockspace) < 0) {
            virReportOOMError();
            return -1;
        }
        if (!(newName = strdup(name)))
            goto no_memory;

    }   break;
    default:
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Unknown lock manager object type %d"),
                       type);
        return -1;
    }

    if (VIR_EXPAND_N(priv->resources, priv->nresources, 1) < 0)
        goto no_memory;

    priv->resources[priv->nresources-1].lockspace = newLockspace;
    priv->resources[priv->nresources-1].name = newName;

    if (flags & VIR_LOCK_MANAGER_RESOURCE_SHARED)
        priv->resources[priv->nresources-1].flags |=
            VIR_LOCK_SPACE_PROTOCOL_ACQUIRE_RESOURCE_SHARED;

    if (autoCreate)
        priv->resources[priv->nresources-1].flags |=
            VIR_LOCK_SPACE_PROTOCOL_ACQUIRE_RESOURCE_AUTOCREATE;

    return 0;

no_memory:
    virReportOOMError();
error:
    VIR_FREE(newLockspace);
    VIR_FREE(newName);
    return -1;
}


static int virLockManagerLockDaemonAcquire(virLockManagerPtr lock,
                                           const char *state ATTRIBUTE_UNUSED,
                                           unsigned int flags,
                                           virDomainLockFailureAction action ATTRIBUTE_UNUSED,
                                           int *fd)
{
    virNetClientPtr client = NULL;
    virNetClientProgramPtr program = NULL;
    int counter = 0;
    int rv = -1;
    virLockManagerLockDaemonPrivatePtr priv = lock->privateData;

    virCheckFlags(VIR_LOCK_MANAGER_ACQUIRE_REGISTER_ONLY |
                  VIR_LOCK_MANAGER_ACQUIRE_RESTRICT, -1);

    if (priv->nresources == 0 &&
        priv->hasRWDisks &&
        driver->requireLeaseForDisks) {
        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                       _("Read/write, exclusive access, disks were present, but no leases specified"));
        return -1;
    }

    if (!(client = virLockManagerLockDaemonConnect(lock, &program, &counter)))
        goto cleanup;

    if (fd &&
        (*fd = virNetClientDupFD(client, false)) < 0)
        goto cleanup;

    if (!(flags & VIR_LOCK_MANAGER_ACQUIRE_REGISTER_ONLY)) {
        size_t i;
        for (i = 0 ; i < priv->nresources ; i++) {
            virLockSpaceProtocolAcquireResourceArgs args;

            memset(&args, 0, sizeof(args));

            if (priv->resources[i].lockspace)
                args.path = priv->resources[i].lockspace;
            args.name = priv->resources[i].name;
            args.flags = priv->resources[i].flags;

            if (virNetClientProgramCall(program,
                                        client,
                                        counter++,
                                        VIR_LOCK_SPACE_PROTOCOL_PROC_ACQUIRE_RESOURCE,
                                        0, NULL, NULL, NULL,
                                        (xdrproc_t)xdr_virLockSpaceProtocolAcquireResourceArgs, &args,
                                        (xdrproc_t)xdr_void, NULL) < 0)
                goto cleanup;
        }
    }

    if ((flags & VIR_LOCK_MANAGER_ACQUIRE_RESTRICT) &&
        virLockManagerLockDaemonConnectionRestrict(lock, client, program, &counter) < 0)
        goto cleanup;

    rv = 0;

cleanup:
    if (rv != 0 && fd)
        VIR_FORCE_CLOSE(*fd);
    virNetClientClose(client);
    virObjectUnref(client);
    virObjectUnref(program);

    return rv;
}

static int virLockManagerLockDaemonRelease(virLockManagerPtr lock,
                                           char **state,
                                           unsigned int flags)
{
    virNetClientPtr client = NULL;
    virNetClientProgramPtr program = NULL;
    int counter = 0;
    virLockSpaceProtocolReleaseResourceArgs args;
    int rv = -1;

    memset(&args, 0, sizeof(args));

    if (state)
        *state = NULL;

    if (!(client = virLockManagerLockDaemonConnect(lock, &program, &counter)))
        goto cleanup;

    args.flags = flags;

    if (virNetClientProgramCall(program,
                                client,
                                counter++,
                                VIR_LOCK_SPACE_PROTOCOL_PROC_RELEASE_RESOURCE,
                                0, NULL, NULL, NULL,
                                (xdrproc_t)xdr_virLockSpaceProtocolReleaseResourceArgs, &args,
                                (xdrproc_t)xdr_void, NULL) < 0)
        goto cleanup;

    rv = 0;

cleanup:
    virNetClientClose(client);
    virObjectUnref(client);
    virObjectUnref(program);

    return rv;
}


static int virLockManagerLockDaemonInquire(virLockManagerPtr lock ATTRIBUTE_UNUSED,
                                           char **state,
                                           unsigned int flags)
{
    virCheckFlags(0, -1);

    if (state)
        *state = NULL;

    return 0;
}

virLockDriver virLockDriverImpl =
{
    .version = VIR_LOCK_MANAGER_VERSION,
    .flags = 0,

    .drvInit = virLockManagerLockDaemonInit,
    .drvDeinit = virLockManagerLockDaemonDeinit,

    .drvNew = virLockManagerLockDaemonNew,
    .drvFree = virLockManagerLockDaemonFree,

    .drvAddResource = virLockManagerLockDaemonAddResource,

    .drvAcquire = virLockManagerLockDaemonAcquire,
    .drvRelease = virLockManagerLockDaemonRelease,

    .drvInquire = virLockManagerLockDaemonInquire,
};