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/*
   Copyright (c) 2013-2014 Red Hat, Inc. <http://www.redhat.com>
   This file is part of GlusterFS.

   This file is licensed to you under your choice of the GNU Lesser
   General Public License, version 3 or any later version (LGPLv3 or
   later), or the GNU General Public License, version 2 (GPLv2), in all
   cases as published by the Free Software Foundation.
*/
#ifndef _CONFIG_H
#define _CONFIG_H
#include "config.h"
#endif

#include "common-utils.h"
#include "cli1-xdr.h"
#include "xdr-generic.h"
#include "glusterd.h"
#include "glusterd-op-sm.h"
#include "glusterd-store.h"
#include "glusterd-utils.h"
#include "glusterd-volgen.h"
#include "glusterd-locks.h"
#include "run.h"
#include "syscall.h"

#include <signal.h>

/* Valid entities that the mgt_v3 lock can hold locks upon */
char   *valid_types[] = { "vol", "snap", NULL };

static dict_t *mgmt_v3_lock;

/* Checks if the lock request is for a valid entity */
gf_boolean_t
glusterd_mgmt_v3_is_type_valid (char *type)
{
        int32_t         i   = 0;
        gf_boolean_t    ret = _gf_false;

        GF_ASSERT (type);

        for (i = 0; valid_types[i]; i++) {
                if (!strcmp (type, valid_types[i])) {
                        ret = _gf_true;
                        break;
                }
        }

        return ret;
}

/* Initialize the global mgmt_v3 lock list(dict) when
 * glusterd is spawned */
int32_t
glusterd_mgmt_v3_lock_init ()
{
        int32_t ret = -1;

        mgmt_v3_lock = dict_new ();
        if (!mgmt_v3_lock) {
                ret = -1;
                goto out;
        }

        ret = 0;
out:
        return ret;
}

/* Destroy the global mgmt_v3 lock list(dict) when
 * glusterd cleanup is performed */
void
glusterd_mgmt_v3_lock_fini ()
{
        if (mgmt_v3_lock)
                dict_destroy (mgmt_v3_lock);
}

int32_t
glusterd_get_mgmt_v3_lock_owner (char *key, uuid_t *uuid)
{
        int32_t             ret      = -1;
        mgmt_v3_lock_obj   *lock_obj = NULL;
        uuid_t              no_owner = {"\0"};

        if (!key || !uuid) {
                gf_log ("", GF_LOG_ERROR, "key or uuid is null.");
                ret = -1;
                goto out;
        }

        ret = dict_get_bin(mgmt_v3_lock, key, (void **) &lock_obj);
        if (!ret)
                uuid_copy (*uuid, lock_obj->lock_owner);
        else
                uuid_copy (*uuid, no_owner);

        ret = 0;
out:
        gf_log ("", GF_LOG_DEBUG, "Returning %d", ret);
        return ret;
}

int32_t
glusterd_multiple_mgmt_v3_unlock (dict_t *dict, uuid_t uuid)
{
        int32_t        ret                   = -1;
        int32_t        op_ret                =  0;
        int32_t        i                     = -1;
        int32_t        volcount              = -1;
        char           volname_buf[PATH_MAX] = "";
        char          *volname               = NULL;

        if (!dict) {
                gf_log ("", GF_LOG_ERROR, "dict is null.");
                ret = -1;
                goto out;
        }

        ret = dict_get_int32 (dict, "volcount", &volcount);
        if (ret) {
                gf_log ("", GF_LOG_DEBUG, "Failed to get volcount"
                        "name");
                goto out;
        }

        /* Unlocking one volume after other */
        for (i = 1; i <= volcount; i++) {
                ret = snprintf (volname_buf, sizeof(volname_buf) - 1,
                                "volname%d", i);
                volname_buf[ret] = '\0';

                ret = dict_get_str (dict, volname_buf, &volname);
                if (ret) {
                        gf_log ("", GF_LOG_ERROR, "Unable to get %s Volcount = %d",
                                volname_buf, volcount);
                        goto out;
                }

                ret = glusterd_mgmt_v3_unlock (volname, uuid, "vol");
                if (ret) {
                        gf_log ("", GF_LOG_ERROR,
                                "Failed to release lock for %s. ", volname);
                        op_ret = ret;
                }
        }

        ret = op_ret;
out:
        gf_log ("", GF_LOG_DEBUG, "Returning %d", ret);
        return ret;
}

int32_t
glusterd_multiple_mgmt_v3_lock (dict_t *dict, uuid_t uuid)
{
        int32_t        ret                   = -1;
        int32_t        i                     = -1;
        int32_t        volcount              = -1;
        char           volname_buf[PATH_MAX] = "";
        char          *volname               = NULL;
        int32_t        locked_volcount       = 0;

        if (!dict) {
                gf_log ("", GF_LOG_ERROR, "dict is null.");
                ret = -1;
                goto out;
        }

        ret = dict_get_int32 (dict, "volcount", &volcount);
        if (ret) {
                gf_log ("", GF_LOG_ERROR, "Failed to get volcount"
                        "name");
                goto out;
        }

        /* Locking one volume after other */
        for (i = 1; i <= volcount; i++) {
                ret = snprintf (volname_buf, sizeof(volname_buf) - 1,
                                "volname%d", i);
                volname_buf[ret] = '\0';

                ret = dict_get_str (dict, volname_buf, &volname);
                if (ret) {
                        gf_log ("", GF_LOG_ERROR, "Unable to get %s Volcount = %d",
                                volname_buf, volcount);
                        goto out;
                }

                ret = glusterd_mgmt_v3_lock (volname, uuid, "vol");
                if (ret) {
                        gf_log ("", GF_LOG_ERROR,
                                "Failed to acquire lock for %s "
                                "on behalf of %s. Reversing "
                                "this transaction", volname,
                                uuid_utoa(uuid));
                        break;
                }
                locked_volcount ++;
        }

        /* If we failed to lock one volume, unlock others and return failure */
        if (volcount != locked_volcount) {
                for (i = 1; i <= locked_volcount; i++) {
                        ret = snprintf (volname_buf, sizeof(volname_buf) - 1,
                                        "volname%d", i);
                        volname_buf[ret] = '\0';

                        ret = dict_get_str (dict, volname_buf, &volname);
                        if (ret) {
                                gf_log ("", GF_LOG_ERROR,
                                        "Unable to get %s lockd_volcount = %d",
                                        volname_buf, volcount);
                                goto out;
                        }

                        ret = glusterd_mgmt_v3_unlock (volname, uuid, "vol");
                        if (ret)
                                gf_log ("", GF_LOG_ERROR,
                                        "Failed to release lock for %s.",
                                        volname);
                }
                ret = -1;
        }

out:
        gf_log ("", GF_LOG_DEBUG, "Returning %d", ret);
        return ret;
}

int32_t
glusterd_mgmt_v3_lock (const char *name, uuid_t uuid, char *type)
{
        char                 key[PATH_MAX] = "";
        int32_t              ret           = -1;
        mgmt_v3_lock_obj    *lock_obj      = NULL;
        gf_boolean_t         is_valid      = _gf_true;
        uuid_t               owner         = {0};

        if (!name || !type) {
                gf_log (THIS->name, GF_LOG_ERROR, "name or type is null.");
                ret = -1;
                goto out;
        }

        is_valid = glusterd_mgmt_v3_is_type_valid (type);
        if (is_valid != _gf_true) {
                gf_log ("", GF_LOG_ERROR,
                        "Invalid entity. Cannot perform locking "
                        "operation on %s types", type);
                ret = -1;
                goto out;
        }

        ret = snprintf (key, sizeof(key), "%s_%s", name, type);
        if (ret != strlen(name) + 1 + strlen(type)) {
                ret = -1;
                gf_log (THIS->name, GF_LOG_ERROR, "Unable to create key");
                goto out;
        }

        gf_log (THIS->name, GF_LOG_DEBUG,
                "Trying to acquire lock of %s %s for %s as %s",
                type, name, uuid_utoa (uuid), key);

        ret = glusterd_get_mgmt_v3_lock_owner (key, &owner);
        if (ret) {
                gf_log (THIS->name, GF_LOG_DEBUG,
                        "Unable to get mgmt_v3 lock owner");
                goto out;
        }

        /* If the lock has already been held for the given volume
         * we fail */
        if (!uuid_is_null (owner)) {
                gf_log (THIS->name, GF_LOG_ERROR, "Lock for %s held by %s",
                        name, uuid_utoa (owner));
                ret = -1;
                goto out;
        }

        lock_obj = GF_CALLOC (1, sizeof(mgmt_v3_lock_obj),
                              gf_common_mt_mgmt_v3_lock_obj_t);
        if (!lock_obj) {
                ret = -1;
                goto out;
        }

        uuid_copy (lock_obj->lock_owner, uuid);

        ret = dict_set_bin (mgmt_v3_lock, key, lock_obj,
                            sizeof(*lock_obj));
        if (ret) {
                gf_log (THIS->name, GF_LOG_ERROR,
                        "Unable to set lock owner in mgmt_v3 lock");
                if (lock_obj)
                        GF_FREE (lock_obj);
                goto out;
        }

        gf_log (THIS->name, GF_LOG_DEBUG,
                "Lock for %s %s successfully held by %s",
                type, name, uuid_utoa (uuid));

        ret = 0;
out:
        gf_log (THIS->name, GF_LOG_TRACE, "Returning %d", ret);
        return ret;
}

int32_t
glusterd_mgmt_v3_unlock (const char *name, uuid_t uuid, char *type)
{
        char           key[PATH_MAX] = "";
        int32_t        ret           = -1;
        gf_boolean_t   is_valid      = _gf_true;
        uuid_t         owner         = {0};

        if (!name || !type) {
                gf_log (THIS->name, GF_LOG_ERROR, "name is null.");
                ret = -1;
                goto out;
        }

        is_valid = glusterd_mgmt_v3_is_type_valid (type);
        if (is_valid != _gf_true) {
                gf_log ("", GF_LOG_ERROR,
                        "Invalid entity. Cannot perform unlocking "
                        "operation on %s types", type);
                ret = -1;
                goto out;
        }

        ret = snprintf (key, sizeof(key), "%s_%s",
                        name, type);
        if (ret != strlen(name) + 1 + strlen(type)) {
                gf_log (THIS->name, GF_LOG_ERROR, "Unable to create key");
                ret = -1;
                goto out;
        }

        gf_log (THIS->name, GF_LOG_DEBUG,
                "Trying to release lock of %s %s for %s as %s",
                type, name, uuid_utoa (uuid), key);

        ret = glusterd_get_mgmt_v3_lock_owner (key, &owner);
        if (ret) {
                gf_log (THIS->name, GF_LOG_DEBUG,
                        "Unable to get mgmt_v3 lock owner");
                goto out;
        }

        if (uuid_is_null (owner)) {
                gf_log (THIS->name, GF_LOG_ERROR,
                        "Lock for %s %s not held", type, name);
                ret = -1;
                goto out;
        }

        ret = uuid_compare (uuid, owner);
        if (ret) {

                gf_log (THIS->name, GF_LOG_ERROR, "Lock owner mismatch. "
                        "Lock for %s %s held by %s",
                        type, name, uuid_utoa (owner));
                goto out;
        }

        /* Removing the mgmt_v3 lock from the global list */
        dict_del (mgmt_v3_lock, key);

        gf_log (THIS->name, GF_LOG_DEBUG,
                "Lock for %s %s successfully released",
                type, name);

        ret = 0;
out:
        gf_log (THIS->name, GF_LOG_TRACE, "Returning %d", ret);
        return ret;
}