libvirt/src/locking/lock_driver_sanlock.c

/*
 * lock_driver_sanlock.c: A lock driver for Sanlock
 *
 * Copyright (C) 2010-2014 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 <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <sanlock.h>
#include <sanlock_resource.h>
#include <sanlock_admin.h>

#include "dirname.h"
#include "lock_driver.h"
#include "virlog.h"
#include "virerror.h"
#include "viralloc.h"
#include "vircrypto.h"
#include "virfile.h"
#include "virconf.h"
#include "virstring.h"

#include "configmake.h"

#define VIR_FROM_THIS VIR_FROM_LOCKING

VIR_LOG_INIT("locking.lock_driver_sanlock");

#define VIR_LOCK_MANAGER_SANLOCK_AUTO_DISK_LOCKSPACE "__LIBVIRT__DISKS__"
#define VIR_LOCK_MANAGER_SANLOCK_KILLPATH LIBEXECDIR "/libvirt_sanlock_helper"

/*
 * temporary fix for the case where the sanlock devel package is
 * too old to provide that define, and probably the functionality too
 */
#ifndef SANLK_RES_SHARED
# define SANLK_RES_SHARED    0x4
#endif

typedef struct _virLockManagerSanlockDriver virLockManagerSanlockDriver;
typedef virLockManagerSanlockDriver *virLockManagerSanlockDriverPtr;

typedef struct _virLockManagerSanlockPrivate virLockManagerSanlockPrivate;
typedef virLockManagerSanlockPrivate *virLockManagerSanlockPrivatePtr;

struct _virLockManagerSanlockDriver {
    bool requireLeaseForDisks;
    int hostID;
    bool autoDiskLease;
    char *autoDiskLeasePath;

    /* under which permissions does sanlock run */
    uid_t user;
    gid_t group;
};

static virLockManagerSanlockDriver *driver = NULL;

struct _virLockManagerSanlockPrivate {
    const char *vm_uri;
    char *vm_name;
    unsigned char vm_uuid[VIR_UUID_BUFLEN];
    unsigned int vm_id;
    unsigned int vm_pid;
    unsigned int flags;
    bool hasRWDisks;
    int res_count;
    struct sanlk_resource *res_args[SANLK_MAX_RESOURCES];
};

/*
 * sanlock plugin for the libvirt virLockManager API
 */
static int virLockManagerSanlockLoadConfig(const char *configFile)
{
    virConfPtr conf;
    virConfValuePtr p;
    char *tmp;

    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, "disk_lease_dir");
    CHECK_TYPE("disk_lease_dir", VIR_CONF_STRING);
    if (p && p->str) {
        VIR_FREE(driver->autoDiskLeasePath);
        if (VIR_STRDUP(driver->autoDiskLeasePath, p->str) < 0) {
            virConfFree(conf);
            return -1;
        }
    }

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

    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;

    p = virConfGetValue(conf, "user");
    CHECK_TYPE("user", VIR_CONF_STRING);
    if (p) {
        if (VIR_STRDUP(tmp, p->str) < 0) {
            virConfFree(conf);
            return -1;
        }

        if (virGetUserID(tmp, &driver->user) < 0) {
            VIR_FREE(tmp);
            virConfFree(conf);
            return -1;
        }
        VIR_FREE(tmp);
    }

    p = virConfGetValue(conf, "group");
    CHECK_TYPE("group", VIR_CONF_STRING);
    if (p) {
        if (VIR_STRDUP(tmp, p->str) < 0) {
            virConfFree(conf);
            return -1;
        }
        if (virGetGroupID(tmp, &driver->group) < 0) {
            VIR_FREE(tmp);
            virConfFree(conf);
            return -1;
        }
        VIR_FREE(tmp);
    }

    virConfFree(conf);
    return 0;
}

/* How much ms sleep before retrying to add a lockspace? */
#define LOCKSPACE_SLEEP 100
/* How many times try adding a lockspace? */
#define LOCKSPACE_RETRIES 10

static int virLockManagerSanlockSetupLockspace(void)
{
    int fd = -1;
    struct stat st;
    int rv;
    struct sanlk_lockspace ls;
    char *path = NULL;
    char *dir = NULL;
    int retries = LOCKSPACE_RETRIES;

    if (virAsprintf(&path, "%s/%s",
                    driver->autoDiskLeasePath,
                    VIR_LOCK_MANAGER_SANLOCK_AUTO_DISK_LOCKSPACE) < 0)
        goto error;

    if (!virStrcpyStatic(ls.name,
                         VIR_LOCK_MANAGER_SANLOCK_AUTO_DISK_LOCKSPACE)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Lockspace path '%s' exceeded %d characters"),
                       VIR_LOCK_MANAGER_SANLOCK_AUTO_DISK_LOCKSPACE,
                       SANLK_PATH_LEN);
        goto error;
    }
    ls.host_id = 0; /* Doesn't matter for initialization */
    ls.flags = 0;
    if (!virStrcpy(ls.host_id_disk.path, path, SANLK_PATH_LEN)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Lockspace path '%s' exceeded %d characters"),
                       path, SANLK_PATH_LEN);
        goto error;
    }
    ls.host_id_disk.offset = 0;

    /* Stage 1: Ensure the lockspace file exists on disk, has
     * space allocated for it and is initialized with lease
     */
    if (stat(path, &st) < 0) {
        int perms = 0600;
        VIR_DEBUG("Lockspace %s does not yet exist", path);

        if (!(dir = mdir_name(path))) {
            virReportOOMError();
            goto error;
        }
        if (stat(dir, &st) < 0 || !S_ISDIR(st.st_mode)) {
            virReportError(VIR_ERR_INTERNAL_ERROR,
                           _("Unable to create lockspace %s: parent directory"
                             " does not exist or is not a directory"),
                           path);
            goto error;
        }

        if (driver->group != (gid_t) -1)
            perms |= 0060;

        if ((fd = open(path, O_WRONLY|O_CREAT|O_EXCL, perms)) < 0) {
            if (errno != EEXIST) {
                virReportSystemError(errno,
                                     _("Unable to create lockspace %s"),
                                     path);
                goto error;
            }
            VIR_DEBUG("Someone else just created lockspace %s", path);
        } else {
            /* chown() the path to make sure sanlock can access it */
            if ((driver->user != (uid_t) -1 || driver->group != (gid_t) -1) &&
                (fchown(fd, driver->user, driver->group) < 0)) {
                virReportSystemError(errno,
                                     _("cannot chown '%s' to (%u, %u)"),
                                     path,
                                     (unsigned int) driver->user,
                                     (unsigned int) driver->group);
                goto error_unlink;
            }

            if ((rv = sanlock_align(&ls.host_id_disk)) < 0) {
                if (rv <= -200)
                    virReportError(VIR_ERR_INTERNAL_ERROR,
                                   _("Unable to query sector size %s: error %d"),
                                   path, rv);
                else
                    virReportSystemError(-rv,
                                         _("Unable to query sector size %s"),
                                         path);
                goto error_unlink;
            }

            /*
             * Pre allocate enough data for 1 block of leases at preferred alignment
             */
            if (safezero(fd, 0, rv) < 0) {
                virReportSystemError(errno,
                                     _("Unable to allocate lockspace %s"),
                                     path);
                goto error_unlink;
            }

            if (VIR_CLOSE(fd) < 0) {
                virReportSystemError(errno,
                                     _("Unable to save lockspace %s"),
                                     path);
                goto error_unlink;
            }

            if ((rv = sanlock_init(&ls, NULL, 0, 0)) < 0) {
                if (rv <= -200)
                    virReportError(VIR_ERR_INTERNAL_ERROR,
                                   _("Unable to initialize lockspace %s: error %d"),
                                   path, rv);
                else
                    virReportSystemError(-rv,
                                         _("Unable to initialize lockspace %s"),
                                         path);
                goto error_unlink;
            }
            VIR_DEBUG("Lockspace %s has been initialized", path);
        }
    } else if (S_ISREG(st.st_mode)) {
        /* okay, the lease file exists. Check the permissions */
        if (((driver->user != (uid_t) -1 && driver->user != st.st_uid) ||
             (driver->group != (gid_t) -1 && driver->group != st.st_gid)) &&
            (chown(path, driver->user, driver->group) < 0)) {
            virReportSystemError(errno,
                                 _("cannot chown '%s' to (%u, %u)"),
                                 path,
                                 (unsigned int) driver->user,
                                 (unsigned int) driver->group);
            goto error;
        }

        if ((driver->group != (gid_t) -1 && (st.st_mode & 0060) != 0060) &&
            chmod(path, 0660) < 0) {
            virReportSystemError(errno,
                                 _("cannot chmod '%s' to 0660"),
                                 path);
            goto error;
        }
    }

    ls.host_id = driver->hostID;
    /* Stage 2: Try to register the lockspace with the daemon.  If the lockspace
     * is already registered, we should get EEXIST back in which case we can
     * just carry on with life. If EINPROGRESS is returned, we have two options:
     * either call a sanlock API that blocks us until lockspace changes state,
     * or we can fallback to polling.
     */
retry:
    if ((rv = sanlock_add_lockspace(&ls, 0)) < 0) {
        if (-rv == EINPROGRESS && --retries) {
#ifdef HAVE_SANLOCK_INQ_LOCKSPACE
            /* we have this function which blocks until lockspace change the
             * state. It returns 0 if lockspace has been added, -ENOENT if it
             * hasn't. */
            VIR_DEBUG("Inquiring lockspace");
            if (sanlock_inq_lockspace(&ls, SANLK_INQ_WAIT) < 0)
                VIR_DEBUG("Unable to inquire lockspace");
#else
            /* fall back to polling */
            VIR_DEBUG("Sleeping for %dms", LOCKSPACE_SLEEP);
            usleep(LOCKSPACE_SLEEP * 1000);
#endif
            VIR_DEBUG("Retrying to add lockspace (left %d)", retries);
            goto retry;
        }
        if (-rv != EEXIST) {
            if (rv <= -200)
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Unable to add lockspace %s: error %d"),
                               path, rv);
            else
                virReportSystemError(-rv,
                                     _("Unable to add lockspace %s"),
                                     path);
            goto error;
        } else {
            VIR_DEBUG("Lockspace %s is already registered", path);
        }
    } else {
        VIR_DEBUG("Lockspace %s has been registered", path);
    }

    VIR_FREE(path);
    VIR_FREE(dir);
    return 0;

error_unlink:
    unlink(path);
error:
    VIR_FORCE_CLOSE(fd);
    VIR_FREE(path);
    VIR_FREE(dir);
    return -1;
}


static int virLockManagerSanlockDeinit(void);
static int virLockManagerSanlockInit(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)
        return -1;

    driver->requireLeaseForDisks = true;
    driver->hostID = 0;
    driver->autoDiskLease = false;
    driver->user = (uid_t) -1;
    driver->group = (gid_t) -1;
    if (VIR_STRDUP(driver->autoDiskLeasePath, LOCALSTATEDIR "/lib/libvirt/sanlock") < 0) {
        VIR_FREE(driver);
        goto error;
    }

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

    if (driver->autoDiskLease && !driver->hostID) {
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("Automatic disk lease mode enabled, but no host ID is set"));
        goto error;
    }

    if (driver->autoDiskLease) {
        if (virLockManagerSanlockSetupLockspace() < 0)
            goto error;
    }

    return 0;

error:
    virLockManagerSanlockDeinit();
    return -1;
}

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

    VIR_FREE(driver->autoDiskLeasePath);
    VIR_FREE(driver);

    return 0;
}


static int virLockManagerSanlockNew(virLockManagerPtr lock,
                                    unsigned int type,
                                    size_t nparams,
                                    virLockManagerParamPtr params,
                                    unsigned int flags)
{
    virLockManagerParamPtr param;
    virLockManagerSanlockPrivatePtr priv;
    size_t i;

    virCheckFlags(0, -1);

    if (!driver) {
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("Sanlock plugin is not initialized"));
        return -1;
    }

    if (type != VIR_LOCK_MANAGER_OBJECT_TYPE_DOMAIN) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Unsupported object type %d"), type);
        return -1;
    }

    if (VIR_ALLOC(priv) < 0)
        return -1;

    priv->flags = flags;

    for (i = 0; i < nparams; i++) {
        param = &params[i];

        if (STREQ(param->key, "uuid")) {
            memcpy(priv->vm_uuid, param->value.uuid, 16);
        } else if (STREQ(param->key, "name")) {
            if (VIR_STRDUP(priv->vm_name, param->value.str) < 0)
                goto error;
        } else if (STREQ(param->key, "pid")) {
            priv->vm_pid = param->value.ui;
        } else if (STREQ(param->key, "id")) {
            priv->vm_id = param->value.ui;
        } else if (STREQ(param->key, "uri")) {
            priv->vm_uri = param->value.cstr;
        }
    }

    lock->privateData = priv;
    return 0;

error:
    VIR_FREE(priv);
    return -1;
}

static void virLockManagerSanlockFree(virLockManagerPtr lock)
{
    virLockManagerSanlockPrivatePtr priv = lock->privateData;
    size_t i;

    if (!priv)
        return;

    VIR_FREE(priv->vm_name);
    for (i = 0; i < priv->res_count; i++)
        VIR_FREE(priv->res_args[i]);
    VIR_FREE(priv);
    lock->privateData = NULL;
}


static int virLockManagerSanlockAddLease(virLockManagerPtr lock,
                                         const char *name,
                                         size_t nparams,
                                         virLockManagerParamPtr params,
                                         bool shared)
{
    virLockManagerSanlockPrivatePtr priv = lock->privateData;
    int ret = -1;
    struct sanlk_resource *res = NULL;
    size_t i;

    if (VIR_ALLOC_VAR(res, struct sanlk_disk, 1) < 0)
        goto cleanup;

    res->flags = shared ? SANLK_RES_SHARED : 0;
    res->num_disks = 1;
    if (!virStrcpy(res->name, name, SANLK_NAME_LEN)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Resource name '%s' exceeds %d characters"),
                       name, SANLK_NAME_LEN);
        goto cleanup;
    }

    for (i = 0; i < nparams; i++) {
        if (STREQ(params[i].key, "path")) {
            if (!virStrcpy(res->disks[0].path, params[i].value.str, SANLK_PATH_LEN)) {
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Lease path '%s' exceeds %d characters"),
                               params[i].value.str, SANLK_PATH_LEN);
                goto cleanup;
            }
        } else if (STREQ(params[i].key, "offset")) {
            res->disks[0].offset = params[i].value.ul;
        } else if (STREQ(params[i].key, "lockspace")) {
            if (!virStrcpy(res->lockspace_name, params[i].value.str, SANLK_NAME_LEN)) {
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Resource lockspace '%s' exceeds %d characters"),
                               params[i].value.str, SANLK_NAME_LEN);
                goto cleanup;
            }
        }
    }

    priv->res_args[priv->res_count] = res;
    priv->res_count++;

    ret = 0;

cleanup:
    if (ret == -1)
        VIR_FREE(res);
    return ret;
}




static int virLockManagerSanlockAddDisk(virLockManagerPtr lock,
                                        const char *name,
                                        size_t nparams,
                                        virLockManagerParamPtr params ATTRIBUTE_UNUSED,
                                        bool shared)
{
    virLockManagerSanlockPrivatePtr priv = lock->privateData;
    int ret = -1;
    struct sanlk_resource *res = NULL;
    char *path = NULL;
    char *hash = NULL;

    if (nparams) {
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("Unexpected lock parameters for disk resource"));
        return -1;
    }

    if (VIR_ALLOC_VAR(res, struct sanlk_disk, 1) < 0)
        goto cleanup;

    res->flags = shared ? SANLK_RES_SHARED : 0;
    res->num_disks = 1;
    if (virCryptoHashString(VIR_CRYPTO_HASH_MD5, name, &hash) < 0)
        goto cleanup;
    if (!virStrcpy(res->name, hash, SANLK_NAME_LEN)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("MD5 hash '%s' unexpectedly larger than %d characters"),
                       hash, (SANLK_NAME_LEN - 1));
        goto cleanup;
    }

    if (virAsprintf(&path, "%s/%s",
                    driver->autoDiskLeasePath, res->name) < 0)
        goto cleanup;
    if (!virStrcpy(res->disks[0].path, path, SANLK_PATH_LEN)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Lease path '%s' exceeds %d characters"),
                       path, SANLK_PATH_LEN);
        goto cleanup;
    }

    if (!virStrcpy(res->lockspace_name,
                   VIR_LOCK_MANAGER_SANLOCK_AUTO_DISK_LOCKSPACE,
                   SANLK_NAME_LEN)) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Resource lockspace '%s' exceeds %d characters"),
                       VIR_LOCK_MANAGER_SANLOCK_AUTO_DISK_LOCKSPACE, SANLK_NAME_LEN);
        goto cleanup;
    }

    priv->res_args[priv->res_count] = res;
    priv->res_count++;

    ret = 0;

cleanup:
    if (ret == -1)
        VIR_FREE(res);
    VIR_FREE(path);
    VIR_FREE(hash);
    return ret;
}


static int virLockManagerSanlockCreateLease(struct sanlk_resource *res)
{
    int fd = -1;
    struct stat st;
    int rv;

    if (stat(res->disks[0].path, &st) < 0) {
        VIR_DEBUG("Lockspace %s does not yet exist", res->disks[0].path);
        if ((fd = open(res->disks[0].path, O_WRONLY|O_CREAT|O_EXCL, 0600)) < 0) {
            if (errno != EEXIST) {
                virReportSystemError(errno,
                                     _("Unable to create lockspace %s"),
                                     res->disks[0].path);
                return -1;
            }
            VIR_DEBUG("Someone else just created lockspace %s", res->disks[0].path);
        } else {
            /* chown() the path to make sure sanlock can access it */
            if ((driver->user != (uid_t) -1 || driver->group != (gid_t) -1) &&
                (fchown(fd, driver->user, driver->group) < 0)) {
                virReportSystemError(errno,
                                     _("cannot chown '%s' to (%u, %u)"),
                                     res->disks[0].path,
                                     (unsigned int) driver->user,
                                     (unsigned int) driver->group);
                goto error_unlink;
            }

            if ((rv = sanlock_align(&res->disks[0])) < 0) {
                if (rv <= -200)
                    virReportError(VIR_ERR_INTERNAL_ERROR,
                                   _("Unable to query sector size %s: error %d"),
                                   res->disks[0].path, rv);
                else
                    virReportSystemError(-rv,
                                         _("Unable to query sector size %s"),
                                         res->disks[0].path);
                goto error_unlink;
            }

            /*
             * Pre allocate enough data for 1 block of leases at preferred alignment
             */
            if (safezero(fd, 0, rv) < 0) {
                virReportSystemError(errno,
                                     _("Unable to allocate lease %s"),
                                     res->disks[0].path);
                goto error_unlink;
            }

            if (VIR_CLOSE(fd) < 0) {
                virReportSystemError(errno,
                                     _("Unable to save lease %s"),
                                     res->disks[0].path);
                goto error_unlink;
            }

            if ((rv = sanlock_init(NULL, res, 0, 0)) < 0) {
                if (rv <= -200)
                    virReportError(VIR_ERR_INTERNAL_ERROR,
                                   _("Unable to initialize lease %s: error %d"),
                                   res->disks[0].path, rv);
                else
                    virReportSystemError(-rv,
                                         _("Unable to initialize lease %s"),
                                         res->disks[0].path);
                goto error_unlink;
            }
            VIR_DEBUG("Lease %s has been initialized", res->disks[0].path);
        }
    }

    return 0;

error_unlink:
    unlink(res->disks[0].path);
    VIR_FORCE_CLOSE(fd);
    return -1;
}


static int virLockManagerSanlockAddResource(virLockManagerPtr lock,
                                            unsigned int type,
                                            const char *name,
                                            size_t nparams,
                                            virLockManagerParamPtr params,
                                            unsigned int flags)
{
    virLockManagerSanlockPrivatePtr priv = lock->privateData;

    virCheckFlags(VIR_LOCK_MANAGER_RESOURCE_READONLY |
                  VIR_LOCK_MANAGER_RESOURCE_SHARED, -1);

    if (priv->res_count == SANLK_MAX_RESOURCES) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Too many resources %d for object"),
                       SANLK_MAX_RESOURCES);
        return -1;
    }

    /* Treat R/O resources as a no-op lock request */
    if (flags & VIR_LOCK_MANAGER_RESOURCE_READONLY)
        return 0;

    switch (type) {
    case VIR_LOCK_MANAGER_RESOURCE_TYPE_DISK:
        if (driver->autoDiskLease) {
            if (virLockManagerSanlockAddDisk(lock, name, nparams, params,
                                             !!(flags & VIR_LOCK_MANAGER_RESOURCE_SHARED)) < 0)
                return -1;

            if (virLockManagerSanlockCreateLease(priv->res_args[priv->res_count-1]) < 0)
                return -1;
        } else {
            if (!(flags & (VIR_LOCK_MANAGER_RESOURCE_SHARED |
                           VIR_LOCK_MANAGER_RESOURCE_READONLY)))
                priv->hasRWDisks = true;
            /* Ignore disk resources without error */
        }
        break;

    case VIR_LOCK_MANAGER_RESOURCE_TYPE_LEASE:
        if (virLockManagerSanlockAddLease(lock, name, nparams, params,
                                          !!(flags & VIR_LOCK_MANAGER_RESOURCE_SHARED)) < 0)
            return -1;
        break;

    default:
        /* Ignore other resources, without error */
        break;
    }

    return 0;
}

#if HAVE_SANLOCK_KILLPATH
static int
virLockManagerSanlockRegisterKillscript(int sock,
                                        const char *vmuri,
                                        const char *uuidstr,
                                        virDomainLockFailureAction action)
{
    virBuffer buf = VIR_BUFFER_INITIALIZER;
    char *path;
    char *args = NULL;
    int ret = -1;
    int rv;

    switch (action) {
    case VIR_DOMAIN_LOCK_FAILURE_DEFAULT:
        return 0;

    case VIR_DOMAIN_LOCK_FAILURE_POWEROFF:
    case VIR_DOMAIN_LOCK_FAILURE_PAUSE:
        break;

    case VIR_DOMAIN_LOCK_FAILURE_RESTART:
    case VIR_DOMAIN_LOCK_FAILURE_IGNORE:
    case VIR_DOMAIN_LOCK_FAILURE_LAST:
        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                       _("Failure action %s is not supported by sanlock"),
                       virDomainLockFailureTypeToString(action));
        goto cleanup;
    }

    virBufferEscape(&buf, '\\', "\\ ", "%s", vmuri);
    virBufferAddLit(&buf, " ");
    virBufferEscape(&buf, '\\', "\\ ", "%s", uuidstr);
    virBufferAddLit(&buf, " ");
    virBufferEscape(&buf, '\\', "\\ ", "%s",
                    virDomainLockFailureTypeToString(action));

    if (virBufferError(&buf)) {
        virBufferFreeAndReset(&buf);
        virReportOOMError();
        goto cleanup;
    }

    /* Unfortunately, sanlock_killpath() does not use const for either
     * path or args even though it will just copy them into its own
     * buffers.
     */
    path = (char *) VIR_LOCK_MANAGER_SANLOCK_KILLPATH;
    args = virBufferContentAndReset(&buf);

    VIR_DEBUG("Register sanlock killpath: %s %s", path, args);

    /* sanlock_killpath() would just crop the strings */
    if (strlen(path) >= SANLK_HELPER_PATH_LEN) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Sanlock helper path is longer than %d: '%s'"),
                       SANLK_HELPER_PATH_LEN - 1, path);
        goto cleanup;
    }
    if (strlen(args) >= SANLK_HELPER_ARGS_LEN) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Sanlock helper arguments are longer than %d:"
                         " '%s'"),
                       SANLK_HELPER_ARGS_LEN - 1, args);
        goto cleanup;
    }

    if ((rv = sanlock_killpath(sock, 0, path, args)) < 0) {
        if (rv <= -200) {
            virReportError(VIR_ERR_INTERNAL_ERROR,
                           _("Failed to register lock failure action:"
                             " error %d"), rv);
        } else {
            virReportSystemError(-rv, "%s",
                                 _("Failed to register lock failure"
                                   " action"));
        }
        goto cleanup;
    }

    ret = 0;

cleanup:
    VIR_FREE(args);
    return ret;
}
#else
static int
virLockManagerSanlockRegisterKillscript(int sock ATTRIBUTE_UNUSED,
                                        const char *vmuri ATTRIBUTE_UNUSED,
                                        const char *uuidstr ATTRIBUTE_UNUSED,
                                        virDomainLockFailureAction action ATTRIBUTE_UNUSED)
{
    virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                   _("sanlock is too old to support lock failure action"));
    return -1;
}
#endif

static int virLockManagerSanlockAcquire(virLockManagerPtr lock,
                                        const char *state,
                                        unsigned int flags,
                                        virDomainLockFailureAction action,
                                        int *fd)
{
    virLockManagerSanlockPrivatePtr priv = lock->privateData;
    struct sanlk_options *opt;
    struct sanlk_resource **res_args;
    int res_count;
    bool res_free = false;
    int sock = -1;
    int rv;
    size_t i;

    virCheckFlags(VIR_LOCK_MANAGER_ACQUIRE_RESTRICT |
                  VIR_LOCK_MANAGER_ACQUIRE_REGISTER_ONLY, -1);

    if (priv->res_count == 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 (VIR_ALLOC(opt) < 0)
        return -1;

    /* sanlock doesn't use owner_name for anything, so it's safe to take just
     * the first SANLK_NAME_LEN - 1 characters from vm_name */
    ignore_value(virStrncpy(opt->owner_name, priv->vm_name,
                            SANLK_NAME_LEN - 1, SANLK_NAME_LEN));

    if (state && STRNEQ(state, "")) {
        if ((rv = sanlock_state_to_args((char *)state,
                                        &res_count,
                                        &res_args)) < 0) {
            if (rv <= -200)
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Unable to parse lock state %s: error %d"),
                               state, rv);
            else
                virReportSystemError(-rv,
                                     _("Unable to parse lock state %s"),
                                     state);
            goto error;
        }
        res_free = true;
    } else {
        res_args = priv->res_args;
        res_count = priv->res_count;
    }

    /* We only initialize 'sock' if we are in the real
     * child process and we need it to be inherited
     *
     * If sock == -1, then sanlock auto-open/closes a
     * temporary sock
     */
    if (priv->vm_pid == getpid()) {
        VIR_DEBUG("Register sanlock %d", flags);
        if ((sock = sanlock_register()) < 0) {
            if (sock <= -200)
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Failed to open socket to sanlock daemon: error %d"),
                               sock);
            else
                virReportSystemError(-sock, "%s",
                                     _("Failed to open socket to sanlock daemon"));
            goto error;
        }

        if (action != VIR_DOMAIN_LOCK_FAILURE_DEFAULT) {
            char uuidstr[VIR_UUID_STRING_BUFLEN];
            virUUIDFormat(priv->vm_uuid, uuidstr);
            if (virLockManagerSanlockRegisterKillscript(sock, priv->vm_uri,
                                                        uuidstr, action) < 0)
                goto error;
        }
    }

    if (!(flags & VIR_LOCK_MANAGER_ACQUIRE_REGISTER_ONLY)) {
        VIR_DEBUG("Acquiring object %u", priv->res_count);
        if ((rv = sanlock_acquire(sock, priv->vm_pid, 0,
                                  priv->res_count, priv->res_args,
                                  opt)) < 0) {
            if (rv <= -200)
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Failed to acquire lock: error %d"), rv);
            else
                virReportSystemError(-rv, "%s",
                                     _("Failed to acquire lock"));
            goto error;
        }
    }

    VIR_FREE(opt);

    /*
     * We are *intentionally* "leaking" sock file descriptor
     * because we want it to be inherited by QEMU. When the
     * sock FD finally closes upon QEMU exit (or crash) then
     * sanlock will notice EOF and release the lock
     */
    if (sock != -1 &&
        virSetInherit(sock, true) < 0)
        goto error;

    if (flags & VIR_LOCK_MANAGER_ACQUIRE_RESTRICT) {
        if ((rv = sanlock_restrict(sock, SANLK_RESTRICT_ALL)) < 0) {
            if (rv <= -200)
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Failed to restrict process: error %d"), rv);
            else
                virReportSystemError(-rv, "%s",
                                     _("Failed to restrict process"));
            goto error;
        }
    }

    VIR_DEBUG("Acquire completed fd=%d", sock);

    if (res_free) {
        for (i = 0; i < res_count; i++) {
            VIR_FREE(res_args[i]);
        }
        VIR_FREE(res_args);
    }

    if (fd)
        *fd = sock;

    return 0;

error:
    if (res_free) {
        for (i = 0; i < res_count; i++) {
            VIR_FREE(res_args[i]);
        }
        VIR_FREE(res_args);
    }
    VIR_FREE(opt);
    VIR_FORCE_CLOSE(sock);
    return -1;
}


static int virLockManagerSanlockRelease(virLockManagerPtr lock,
                                        char **state,
                                        unsigned int flags)
{
    virLockManagerSanlockPrivatePtr priv = lock->privateData;
    int res_count = priv->res_count;
    int rv;

    virCheckFlags(0, -1);

    if (state) {
        if ((rv = sanlock_inquire(-1, priv->vm_pid, 0, &res_count, state)) < 0) {
            if (rv <= -200)
                virReportError(VIR_ERR_INTERNAL_ERROR,
                               _("Failed to inquire lock: error %d"), rv);
            else
                virReportSystemError(-rv, "%s",
                                     _("Failed to inquire lock"));
            return -1;
        }

        if (STREQ_NULLABLE(*state, ""))
            VIR_FREE(*state);
    }

    if ((rv = sanlock_release(-1, priv->vm_pid, 0, res_count,
                              priv->res_args)) < 0) {
        if (rv <= -200)
            virReportError(VIR_ERR_INTERNAL_ERROR,
                           _("Failed to release lock: error %d"), rv);
        else
            virReportSystemError(-rv, "%s",
                                 _("Failed to release lock"));
        return -1;
    }

    return 0;
}

static int virLockManagerSanlockInquire(virLockManagerPtr lock,
                                        char **state,
                                        unsigned int flags)
{
    virLockManagerSanlockPrivatePtr priv = lock->privateData;
    int rv, res_count;

    virCheckFlags(0, -1);

    if (!state) {
        virReportError(VIR_ERR_INVALID_ARG, __FUNCTION__);
        return -1;
    }

    VIR_DEBUG("pid=%d", priv->vm_pid);

    if ((rv = sanlock_inquire(-1, priv->vm_pid, 0, &res_count, state)) < 0) {
        if (rv <= -200)
            virReportError(VIR_ERR_INTERNAL_ERROR,
                           _("Failed to inquire lock: error %d"), rv);
        else
            virReportSystemError(-rv, "%s",
                                 _("Failed to inquire lock"));
        return -1;
    }

    if (STREQ_NULLABLE(*state, ""))
        VIR_FREE(*state);

    return 0;
}

virLockDriver virLockDriverImpl =
{
    .version = VIR_LOCK_MANAGER_VERSION,

    .flags = VIR_LOCK_MANAGER_USES_STATE,

    .drvInit = virLockManagerSanlockInit,
    .drvDeinit = virLockManagerSanlockDeinit,

    .drvNew = virLockManagerSanlockNew,
    .drvFree = virLockManagerSanlockFree,

    .drvAddResource = virLockManagerSanlockAddResource,

    .drvAcquire = virLockManagerSanlockAcquire,
    .drvRelease = virLockManagerSanlockRelease,
    .drvInquire = virLockManagerSanlockInquire,
};