Add IPv6 support to ADS client side LDAP connects. Corrected format for IPv6 LDAP...

[Samba.git] / ctdb / server / ctdb_recover.c

/* 
   ctdb recovery code

   Copyright (C) Andrew Tridgell  2007
   Copyright (C) Ronnie Sahlberg  2007

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "tdb.h"
#include "system/time.h"
#include "system/network.h"
#include "system/filesys.h"
#include "system/wait.h"
#include "../include/ctdb_private.h"
#include "lib/util/dlinklist.h"
#include "lib/tdb_wrap/tdb_wrap.h"


int 
ctdb_control_getvnnmap(struct ctdb_context *ctdb, uint32_t opcode, TDB_DATA indata, TDB_DATA *outdata)
{
        struct ctdb_vnn_map_wire *map;
        size_t len;

        CHECK_CONTROL_DATA_SIZE(0);

        len = offsetof(struct ctdb_vnn_map_wire, map) + sizeof(uint32_t)*ctdb->vnn_map->size;
        map = talloc_size(outdata, len);
        CTDB_NO_MEMORY(ctdb, map);

        map->generation = ctdb->vnn_map->generation;
        map->size = ctdb->vnn_map->size;
        memcpy(map->map, ctdb->vnn_map->map, sizeof(uint32_t)*map->size);

        outdata->dsize = len;
        outdata->dptr  = (uint8_t *)map;

        return 0;
}

int 
ctdb_control_setvnnmap(struct ctdb_context *ctdb, uint32_t opcode, TDB_DATA indata, TDB_DATA *outdata)
{
        struct ctdb_vnn_map_wire *map = (struct ctdb_vnn_map_wire *)indata.dptr;
        int i;

        for(i=1; i<=NUM_DB_PRIORITIES; i++) {
                if (ctdb->freeze_mode[i] != CTDB_FREEZE_FROZEN) {
                        DEBUG(DEBUG_ERR,("Attempt to set vnnmap when not frozen\n"));
                        return -1;
                }
        }

        talloc_free(ctdb->vnn_map);

        ctdb->vnn_map = talloc(ctdb, struct ctdb_vnn_map);
        CTDB_NO_MEMORY(ctdb, ctdb->vnn_map);

        ctdb->vnn_map->generation = map->generation;
        ctdb->vnn_map->size       = map->size;
        ctdb->vnn_map->map = talloc_array(ctdb->vnn_map, uint32_t, map->size);
        CTDB_NO_MEMORY(ctdb, ctdb->vnn_map->map);

        memcpy(ctdb->vnn_map->map, map->map, sizeof(uint32_t)*map->size);

        return 0;
}

int 
ctdb_control_getdbmap(struct ctdb_context *ctdb, uint32_t opcode, TDB_DATA indata, TDB_DATA *outdata)
{
        uint32_t i, len;
        struct ctdb_db_context *ctdb_db;
        struct ctdb_dbid_map *dbid_map;

        CHECK_CONTROL_DATA_SIZE(0);

        len = 0;
        for(ctdb_db=ctdb->db_list;ctdb_db;ctdb_db=ctdb_db->next){
                len++;
        }


        outdata->dsize = offsetof(struct ctdb_dbid_map, dbs) + sizeof(dbid_map->dbs[0])*len;
        outdata->dptr  = (unsigned char *)talloc_zero_size(outdata, outdata->dsize);
        if (!outdata->dptr) {
                DEBUG(DEBUG_ALERT, (__location__ " Failed to allocate dbmap array\n"));
                exit(1);
        }

        dbid_map = (struct ctdb_dbid_map *)outdata->dptr;
        dbid_map->num = len;
        for (i=0,ctdb_db=ctdb->db_list;ctdb_db;i++,ctdb_db=ctdb_db->next){
                dbid_map->dbs[i].dbid       = ctdb_db->db_id;
                if (ctdb_db->persistent != 0) {
                        dbid_map->dbs[i].flags |= CTDB_DB_FLAGS_PERSISTENT;
                }
                if (ctdb_db->readonly != 0) {
                        dbid_map->dbs[i].flags |= CTDB_DB_FLAGS_READONLY;
                }
                if (ctdb_db->sticky != 0) {
                        dbid_map->dbs[i].flags |= CTDB_DB_FLAGS_STICKY;
                }
        }

        return 0;
}

int
ctdb_control_getnodemap(struct ctdb_context *ctdb, uint32_t opcode, TDB_DATA indata, TDB_DATA *outdata)
{
        CHECK_CONTROL_DATA_SIZE(0);

        outdata->dptr  = (unsigned char *)ctdb_node_list_to_map(ctdb->nodes,
                                                                ctdb->num_nodes,
                                                                outdata);
        if (outdata->dptr == NULL) {
                return -1;
        }

        outdata->dsize = talloc_get_size(outdata->dptr);

        return 0;
}

/*
  reload the nodes file
*/
int
ctdb_control_reload_nodes_file(struct ctdb_context *ctdb, uint32_t opcode)
{
        int i, num_nodes;
        TALLOC_CTX *tmp_ctx;
        struct ctdb_node **nodes;

        tmp_ctx = talloc_new(ctdb);

        /* steal the old nodes file for a while */
        talloc_steal(tmp_ctx, ctdb->nodes);
        nodes = ctdb->nodes;
        ctdb->nodes = NULL;
        num_nodes = ctdb->num_nodes;
        ctdb->num_nodes = 0;

        /* load the new nodes file */
        ctdb_load_nodes_file(ctdb);

        for (i=0; i<ctdb->num_nodes; i++) {
                /* keep any identical pre-existing nodes and connections */
                if ((i < num_nodes) && ctdb_same_address(&ctdb->nodes[i]->address, &nodes[i]->address)) {
                        talloc_free(ctdb->nodes[i]);
                        ctdb->nodes[i] = talloc_steal(ctdb->nodes, nodes[i]);
                        continue;
                }

                if (ctdb->nodes[i]->flags & NODE_FLAGS_DELETED) {
                        continue;
                }

                /* any new or different nodes must be added */
                if (ctdb->methods->add_node(ctdb->nodes[i]) != 0) {
                        DEBUG(DEBUG_CRIT, (__location__ " methods->add_node failed at %d\n", i));
                        ctdb_fatal(ctdb, "failed to add node. shutting down\n");
                }
                if (ctdb->methods->connect_node(ctdb->nodes[i]) != 0) {
                        DEBUG(DEBUG_CRIT, (__location__ " methods->add_connect failed at %d\n", i));
                        ctdb_fatal(ctdb, "failed to connect to node. shutting down\n");
                }
        }

        /* tell the recovery daemon to reaload the nodes file too */
        ctdb_daemon_send_message(ctdb, ctdb->pnn, CTDB_SRVID_RELOAD_NODES, tdb_null);

        talloc_free(tmp_ctx);

        return 0;
}

/* 
   a traverse function for pulling all relevent records from pulldb
 */
struct pulldb_data {
        struct ctdb_context *ctdb;
        struct ctdb_db_context *ctdb_db;
        struct ctdb_marshall_buffer *pulldata;
        uint32_t len;
        uint32_t allocated_len;
        bool failed;
};

static int traverse_pulldb(struct tdb_context *tdb, TDB_DATA key, TDB_DATA data, void *p)
{
        struct pulldb_data *params = (struct pulldb_data *)p;
        struct ctdb_rec_data *rec;
        struct ctdb_context *ctdb = params->ctdb;
        struct ctdb_db_context *ctdb_db = params->ctdb_db;

        /* add the record to the blob */
        rec = ctdb_marshall_record(params->pulldata, 0, key, NULL, data);
        if (rec == NULL) {
                params->failed = true;
                return -1;
        }
        if (params->len + rec->length >= params->allocated_len) {
                params->allocated_len = rec->length + params->len + ctdb->tunable.pulldb_preallocation_size;
                params->pulldata = talloc_realloc_size(NULL, params->pulldata, params->allocated_len);
        }
        if (params->pulldata == NULL) {
                DEBUG(DEBUG_CRIT,(__location__ " Failed to expand pulldb_data to %u\n", rec->length + params->len));
                ctdb_fatal(params->ctdb, "failed to allocate memory for recovery. shutting down\n");
        }
        params->pulldata->count++;
        memcpy(params->len+(uint8_t *)params->pulldata, rec, rec->length);
        params->len += rec->length;

        if (ctdb->tunable.db_record_size_warn != 0 && rec->length > ctdb->tunable.db_record_size_warn) {
                DEBUG(DEBUG_ERR,("Data record in %s is big. Record size is %d bytes\n", ctdb_db->db_name, (int)rec->length));
        }

        talloc_free(rec);

        return 0;
}

/*
  pull a bunch of records from a ltdb, filtering by lmaster
 */
int32_t ctdb_control_pull_db(struct ctdb_context *ctdb, TDB_DATA indata, TDB_DATA *outdata)
{
        struct ctdb_control_pulldb *pull;
        struct ctdb_db_context *ctdb_db;
        struct pulldb_data params;
        struct ctdb_marshall_buffer *reply;

        pull = (struct ctdb_control_pulldb *)indata.dptr;
        
        ctdb_db = find_ctdb_db(ctdb, pull->db_id);
        if (!ctdb_db) {
                DEBUG(DEBUG_ERR,(__location__ " Unknown db 0x%08x\n", pull->db_id));
                return -1;
        }

        if (ctdb->freeze_mode[ctdb_db->priority] != CTDB_FREEZE_FROZEN) {
                DEBUG(DEBUG_DEBUG,("rejecting ctdb_control_pull_db when not frozen\n"));
                return -1;
        }

        reply = talloc_zero(outdata, struct ctdb_marshall_buffer);
        CTDB_NO_MEMORY(ctdb, reply);

        reply->db_id = pull->db_id;

        params.ctdb = ctdb;
        params.ctdb_db = ctdb_db;
        params.pulldata = reply;
        params.len = offsetof(struct ctdb_marshall_buffer, data);
        params.allocated_len = params.len;
        params.failed = false;

        if (ctdb_db->unhealthy_reason) {
                /* this is just a warning, as the tdb should be empty anyway */
                DEBUG(DEBUG_WARNING,("db(%s) unhealty in ctdb_control_pull_db: %s\n",
                                     ctdb_db->db_name, ctdb_db->unhealthy_reason));
        }

        if (ctdb_lockall_mark_prio(ctdb, ctdb_db->priority) != 0) {
                DEBUG(DEBUG_ERR,(__location__ " Failed to get lock on entired db - failing\n"));
                return -1;
        }

        if (tdb_traverse_read(ctdb_db->ltdb->tdb, traverse_pulldb, &params) == -1) {
                DEBUG(DEBUG_ERR,(__location__ " Failed to get traverse db '%s'\n", ctdb_db->db_name));
                ctdb_lockall_unmark_prio(ctdb, ctdb_db->priority);
                talloc_free(params.pulldata);
                return -1;
        }

        ctdb_lockall_unmark_prio(ctdb, ctdb_db->priority);

        outdata->dptr = (uint8_t *)params.pulldata;
        outdata->dsize = params.len;

        if (ctdb->tunable.db_record_count_warn != 0 && params.pulldata->count > ctdb->tunable.db_record_count_warn) {
                DEBUG(DEBUG_ERR,("Database %s is big. Contains %d records\n", ctdb_db->db_name, params.pulldata->count));
        }
        if (ctdb->tunable.db_size_warn != 0 && outdata->dsize > ctdb->tunable.db_size_warn) {
                DEBUG(DEBUG_ERR,("Database %s is big. Contains %d bytes\n", ctdb_db->db_name, (int)outdata->dsize));
        }


        return 0;
}

/*
  push a bunch of records into a ltdb, filtering by rsn
 */
int32_t ctdb_control_push_db(struct ctdb_context *ctdb, TDB_DATA indata)
{
        struct ctdb_marshall_buffer *reply = (struct ctdb_marshall_buffer *)indata.dptr;
        struct ctdb_db_context *ctdb_db;
        int i, ret;
        struct ctdb_rec_data *rec;

        if (indata.dsize < offsetof(struct ctdb_marshall_buffer, data)) {
                DEBUG(DEBUG_ERR,(__location__ " invalid data in pulldb reply\n"));
                return -1;
        }

        ctdb_db = find_ctdb_db(ctdb, reply->db_id);
        if (!ctdb_db) {
                DEBUG(DEBUG_ERR,(__location__ " Unknown db 0x%08x\n", reply->db_id));
                return -1;
        }

        if (ctdb->freeze_mode[ctdb_db->priority] != CTDB_FREEZE_FROZEN) {
                DEBUG(DEBUG_DEBUG,("rejecting ctdb_control_push_db when not frozen\n"));
                return -1;
        }

        if (ctdb_lockall_mark_prio(ctdb, ctdb_db->priority) != 0) {
                DEBUG(DEBUG_ERR,(__location__ " Failed to get lock on entired db - failing\n"));
                return -1;
        }

        rec = (struct ctdb_rec_data *)&reply->data[0];

        DEBUG(DEBUG_INFO,("starting push of %u records for dbid 0x%x\n",
                 reply->count, reply->db_id));

        for (i=0;i<reply->count;i++) {
                TDB_DATA key, data;
                struct ctdb_ltdb_header *hdr;

                key.dptr = &rec->data[0];
                key.dsize = rec->keylen;
                data.dptr = &rec->data[key.dsize];
                data.dsize = rec->datalen;

                if (data.dsize < sizeof(struct ctdb_ltdb_header)) {
                        DEBUG(DEBUG_CRIT,(__location__ " bad ltdb record\n"));
                        goto failed;
                }
                hdr = (struct ctdb_ltdb_header *)data.dptr;
                /* strip off any read only record flags. All readonly records
                   are revoked implicitely by a recovery
                */
                hdr->flags &= ~CTDB_REC_RO_FLAGS;

                data.dptr += sizeof(*hdr);
                data.dsize -= sizeof(*hdr);

                ret = ctdb_ltdb_store(ctdb_db, key, hdr, data);
                if (ret != 0) {
                        DEBUG(DEBUG_CRIT, (__location__ " Unable to store record\n"));
                        goto failed;
                }

                rec = (struct ctdb_rec_data *)(rec->length + (uint8_t *)rec);
        }           

        DEBUG(DEBUG_DEBUG,("finished push of %u records for dbid 0x%x\n",
                 reply->count, reply->db_id));

        if (ctdb_db->readonly) {
                DEBUG(DEBUG_CRIT,("Clearing the tracking database for dbid 0x%x\n",
                                  ctdb_db->db_id));
                if (tdb_wipe_all(ctdb_db->rottdb) != 0) {
                        DEBUG(DEBUG_ERR,("Failed to wipe tracking database for 0x%x. Dropping read-only delegation support\n", ctdb_db->db_id));
                        ctdb_db->readonly = false;
                        tdb_close(ctdb_db->rottdb);
                        ctdb_db->rottdb = NULL;
                        ctdb_db->readonly = false;
                }
                while (ctdb_db->revokechild_active != NULL) {
                        talloc_free(ctdb_db->revokechild_active);
                }
        }

        ctdb_lockall_unmark_prio(ctdb, ctdb_db->priority);
        return 0;

failed:
        ctdb_lockall_unmark_prio(ctdb, ctdb_db->priority);
        return -1;
}

struct ctdb_set_recmode_state {
        struct ctdb_context *ctdb;
        struct ctdb_req_control *c;
        uint32_t recmode;
        int fd[2];
        struct timed_event *te;
        struct fd_event *fde;
        pid_t child;
        struct timeval start_time;
};

/*
  called if our set_recmode child times out. this would happen if
  ctdb_recovery_lock() would block.
 */
static void ctdb_set_recmode_timeout(struct event_context *ev, struct timed_event *te, 
                                         struct timeval t, void *private_data)
{
        struct ctdb_set_recmode_state *state = talloc_get_type(private_data, 
                                           struct ctdb_set_recmode_state);

        /* we consider this a success, not a failure, as we failed to
           set the recovery lock which is what we wanted.  This can be
           caused by the cluster filesystem being very slow to
           arbitrate locks immediately after a node failure.       
         */
        DEBUG(DEBUG_ERR,(__location__ " set_recmode child process hung/timedout CFS slow to grant locks? (allowing recmode set anyway)\n"));
        state->ctdb->recovery_mode = state->recmode;
        ctdb_request_control_reply(state->ctdb, state->c, NULL, 0, NULL);
        talloc_free(state);
}


/* when we free the recmode state we must kill any child process.
*/
static int set_recmode_destructor(struct ctdb_set_recmode_state *state)
{
        double l = timeval_elapsed(&state->start_time);

        CTDB_UPDATE_RECLOCK_LATENCY(state->ctdb, "daemon reclock", reclock.ctdbd, l);

        if (state->fd[0] != -1) {
                state->fd[0] = -1;
        }
        if (state->fd[1] != -1) {
                state->fd[1] = -1;
        }
        ctdb_kill(state->ctdb, state->child, SIGKILL);
        return 0;
}

/* this is called when the client process has completed ctdb_recovery_lock()
   and has written data back to us through the pipe.
*/
static void set_recmode_handler(struct event_context *ev, struct fd_event *fde, 
                             uint16_t flags, void *private_data)
{
        struct ctdb_set_recmode_state *state= talloc_get_type(private_data, 
                                             struct ctdb_set_recmode_state);
        char c = 0;
        int ret;

        /* we got a response from our child process so we can abort the
           timeout.
        */
        talloc_free(state->te);
        state->te = NULL;


        /* If, as expected, the child was unable to take the recovery
         * lock then it will have written 0 into the pipe, so
         * continue.  However, any other value (e.g. 1) indicates that
         * it was able to take the recovery lock when it should have
         * been held by the recovery daemon on the recovery master.
        */
        ret = sys_read(state->fd[0], &c, 1);
        if (ret != 1 || c != 0) {
                ctdb_request_control_reply(
                        state->ctdb, state->c, NULL, -1,
                        "Took recovery lock from daemon during recovery - probably a cluster filesystem lock coherence problem");
                talloc_free(state);
                return;
        }

        state->ctdb->recovery_mode = state->recmode;

        /* release any deferred attach calls from clients */
        if (state->recmode == CTDB_RECOVERY_NORMAL) {
                ctdb_process_deferred_attach(state->ctdb);
        }

        ctdb_request_control_reply(state->ctdb, state->c, NULL, 0, NULL);
        talloc_free(state);
        return;
}

static void
ctdb_drop_all_ips_event(struct event_context *ev, struct timed_event *te, 
                               struct timeval t, void *private_data)
{
        struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);

        DEBUG(DEBUG_ERR,(__location__ " Been in recovery mode for too long. Dropping all IPS\n"));
        talloc_free(ctdb->release_ips_ctx);
        ctdb->release_ips_ctx = NULL;

        ctdb_release_all_ips(ctdb);
}

/*
 * Set up an event to drop all public ips if we remain in recovery for too
 * long
 */
int ctdb_deferred_drop_all_ips(struct ctdb_context *ctdb)
{
        if (ctdb->release_ips_ctx != NULL) {
                talloc_free(ctdb->release_ips_ctx);
        }
        ctdb->release_ips_ctx = talloc_new(ctdb);
        CTDB_NO_MEMORY(ctdb, ctdb->release_ips_ctx);

        event_add_timed(ctdb->ev, ctdb->release_ips_ctx, timeval_current_ofs(ctdb->tunable.recovery_drop_all_ips, 0), ctdb_drop_all_ips_event, ctdb);
        return 0;
}

/*
  set the recovery mode
 */
int32_t ctdb_control_set_recmode(struct ctdb_context *ctdb, 
                                 struct ctdb_req_control *c,
                                 TDB_DATA indata, bool *async_reply,
                                 const char **errormsg)
{
        uint32_t recmode = *(uint32_t *)indata.dptr;
        int i, ret;
        struct ctdb_set_recmode_state *state;
        pid_t parent = getpid();

        /* if we enter recovery but stay in recovery for too long
           we will eventually drop all our ip addresses
        */
        if (recmode == CTDB_RECOVERY_NORMAL) {
                talloc_free(ctdb->release_ips_ctx);
                ctdb->release_ips_ctx = NULL;
        } else {
                if (ctdb_deferred_drop_all_ips(ctdb) != 0) {
                        DEBUG(DEBUG_ERR,("Failed to set up deferred drop all ips\n"));
                }
        }

        if (recmode != ctdb->recovery_mode) {
                DEBUG(DEBUG_NOTICE,(__location__ " Recovery mode set to %s\n", 
                         recmode==CTDB_RECOVERY_NORMAL?"NORMAL":"ACTIVE"));
        }

        if (recmode != CTDB_RECOVERY_NORMAL ||
            ctdb->recovery_mode != CTDB_RECOVERY_ACTIVE) {
                ctdb->recovery_mode = recmode;
                return 0;
        }

        /* some special handling when ending recovery mode */

        /* force the databases to thaw */
        for (i=1; i<=NUM_DB_PRIORITIES; i++) {
                if (ctdb->freeze_handles[i] != NULL) {
                        ctdb_control_thaw(ctdb, i, false);
                }
        }

        state = talloc(ctdb, struct ctdb_set_recmode_state);
        CTDB_NO_MEMORY(ctdb, state);

        state->start_time = timeval_current();
        state->fd[0] = -1;
        state->fd[1] = -1;

        /* release any deferred attach calls from clients */
        if (recmode == CTDB_RECOVERY_NORMAL) {
                ctdb_process_deferred_attach(ctdb);
        }

        if (ctdb->recovery_lock_file == NULL) {
                /* Not using recovery lock file */
                ctdb->recovery_mode = recmode;
                return 0;
        }

        /* For the rest of what needs to be done, we need to do this in
           a child process since 
           1, the call to ctdb_recovery_lock() can block if the cluster
              filesystem is in the process of recovery.
        */
        ret = pipe(state->fd);
        if (ret != 0) {
                talloc_free(state);
                DEBUG(DEBUG_CRIT,(__location__ " Failed to open pipe for set_recmode child\n"));
                return -1;
        }

        state->child = ctdb_fork(ctdb);
        if (state->child == (pid_t)-1) {
                close(state->fd[0]);
                close(state->fd[1]);
                talloc_free(state);
                return -1;
        }

        if (state->child == 0) {
                char cc = 0;
                close(state->fd[0]);

                ctdb_set_process_name("ctdb_recmode");
                debug_extra = talloc_asprintf(NULL, "set_recmode:");
                /* Daemon should not be able to get the recover lock,
                 * as it should be held by the recovery master */
                if (ctdb_recovery_lock(ctdb)) {
                        DEBUG(DEBUG_ERR,
                              ("ERROR: Daemon able to take recovery lock on \"%s\" during recovery\n",
                               ctdb->recovery_lock_file));
                        ctdb_recovery_unlock(ctdb);
                        cc = 1;
                }

                sys_write(state->fd[1], &cc, 1);
                /* make sure we die when our parent dies */
                while (ctdb_kill(ctdb, parent, 0) == 0 || errno != ESRCH) {
                        sleep(5);
                        sys_write(state->fd[1], &cc, 1);
                }
                _exit(0);
        }
        close(state->fd[1]);
        set_close_on_exec(state->fd[0]);

        state->fd[1] = -1;

        talloc_set_destructor(state, set_recmode_destructor);

        DEBUG(DEBUG_DEBUG, (__location__ " Created PIPE FD:%d for setrecmode\n", state->fd[0]));

        state->te = event_add_timed(ctdb->ev, state, timeval_current_ofs(5, 0),
                                    ctdb_set_recmode_timeout, state);

        state->fde = event_add_fd(ctdb->ev, state, state->fd[0],
                                EVENT_FD_READ,
                                set_recmode_handler,
                                (void *)state);

        if (state->fde == NULL) {
                talloc_free(state);
                return -1;
        }
        tevent_fd_set_auto_close(state->fde);

        state->ctdb    = ctdb;
        state->recmode = recmode;
        state->c       = talloc_steal(state, c);

        *async_reply = true;

        return 0;
}


bool ctdb_recovery_have_lock(struct ctdb_context *ctdb)
{
        return ctdb->recovery_lock_fd != -1;
}

/*
  try and get the recovery lock in shared storage - should only work
  on the recovery master recovery daemon. Anywhere else is a bug
 */
bool ctdb_recovery_lock(struct ctdb_context *ctdb)
{
        struct flock lock;

        ctdb->recovery_lock_fd = open(ctdb->recovery_lock_file,
                                      O_RDWR|O_CREAT, 0600);
        if (ctdb->recovery_lock_fd == -1) {
                DEBUG(DEBUG_ERR,
                      ("ctdb_recovery_lock: Unable to open %s - (%s)\n",
                       ctdb->recovery_lock_file, strerror(errno)));
                return false;
        }

        set_close_on_exec(ctdb->recovery_lock_fd);

        lock.l_type = F_WRLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = 0;
        lock.l_len = 1;
        lock.l_pid = 0;

        if (fcntl(ctdb->recovery_lock_fd, F_SETLK, &lock) != 0) {
                int saved_errno = errno;
                close(ctdb->recovery_lock_fd);
                ctdb->recovery_lock_fd = -1;
                /* Fail silently on these errors, since they indicate
                 * lock contention, but log an error for any other
                 * failure. */
                if (saved_errno != EACCES &&
                    saved_errno != EAGAIN) {
                        DEBUG(DEBUG_ERR,("ctdb_recovery_lock: Failed to get "
                                         "recovery lock on '%s' - (%s)\n",
                                         ctdb->recovery_lock_file,
                                         strerror(saved_errno)));
                }
                return false;
        }

        return true;
}

void ctdb_recovery_unlock(struct ctdb_context *ctdb)
{
        if (ctdb->recovery_lock_fd != -1) {
                DEBUG(DEBUG_NOTICE, ("Releasing recovery lock\n"));
                close(ctdb->recovery_lock_fd);
                ctdb->recovery_lock_fd = -1;
        }
}

/*
  delete a record as part of the vacuum process
  only delete if we are not lmaster or dmaster, and our rsn is <= the provided rsn
  use non-blocking locks

  return 0 if the record was successfully deleted (i.e. it does not exist
  when the function returns)
  or !0 is the record still exists in the tdb after returning.
 */
static int delete_tdb_record(struct ctdb_context *ctdb, struct ctdb_db_context *ctdb_db, struct ctdb_rec_data *rec)
{
        TDB_DATA key, data, data2;
        struct ctdb_ltdb_header *hdr, *hdr2;
        
        /* these are really internal tdb functions - but we need them here for
           non-blocking lock of the freelist */
        int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype);
        int tdb_unlock(struct tdb_context *tdb, int list, int ltype);


        key.dsize = rec->keylen;
        key.dptr  = &rec->data[0];
        data.dsize = rec->datalen;
        data.dptr = &rec->data[rec->keylen];

        if (ctdb_lmaster(ctdb, &key) == ctdb->pnn) {
                DEBUG(DEBUG_INFO,(__location__ " Called delete on record where we are lmaster\n"));
                return -1;
        }

        if (data.dsize != sizeof(struct ctdb_ltdb_header)) {
                DEBUG(DEBUG_ERR,(__location__ " Bad record size\n"));
                return -1;
        }

        hdr = (struct ctdb_ltdb_header *)data.dptr;

        /* use a non-blocking lock */
        if (tdb_chainlock_nonblock(ctdb_db->ltdb->tdb, key) != 0) {
                return -1;
        }

        data2 = tdb_fetch(ctdb_db->ltdb->tdb, key);
        if (data2.dptr == NULL) {
                tdb_chainunlock(ctdb_db->ltdb->tdb, key);
                return 0;
        }

        if (data2.dsize < sizeof(struct ctdb_ltdb_header)) {
                if (tdb_lock_nonblock(ctdb_db->ltdb->tdb, -1, F_WRLCK) == 0) {
                        if (tdb_delete(ctdb_db->ltdb->tdb, key) != 0) {
                                DEBUG(DEBUG_CRIT,(__location__ " Failed to delete corrupt record\n"));
                        }
                        tdb_unlock(ctdb_db->ltdb->tdb, -1, F_WRLCK);
                        DEBUG(DEBUG_CRIT,(__location__ " Deleted corrupt record\n"));
                }
                tdb_chainunlock(ctdb_db->ltdb->tdb, key);
                free(data2.dptr);
                return 0;
        }
        
        hdr2 = (struct ctdb_ltdb_header *)data2.dptr;

        if (hdr2->rsn > hdr->rsn) {
                tdb_chainunlock(ctdb_db->ltdb->tdb, key);
                DEBUG(DEBUG_INFO,(__location__ " Skipping record with rsn=%llu - called with rsn=%llu\n",
                         (unsigned long long)hdr2->rsn, (unsigned long long)hdr->rsn));
                free(data2.dptr);
                return -1;
        }

        /* do not allow deleting record that have readonly flags set. */
        if (hdr->flags & CTDB_REC_RO_FLAGS) {
                tdb_chainunlock(ctdb_db->ltdb->tdb, key);
                DEBUG(DEBUG_INFO,(__location__ " Skipping record with readonly flags set\n"));
                free(data2.dptr);
                return -1;
        }
        if (hdr2->flags & CTDB_REC_RO_FLAGS) {
                tdb_chainunlock(ctdb_db->ltdb->tdb, key);
                DEBUG(DEBUG_INFO,(__location__ " Skipping record with readonly flags set\n"));
                free(data2.dptr);
                return -1;
        }

        if (hdr2->dmaster == ctdb->pnn) {
                tdb_chainunlock(ctdb_db->ltdb->tdb, key);
                DEBUG(DEBUG_INFO,(__location__ " Attempted delete record where we are the dmaster\n"));
                free(data2.dptr);
                return -1;
        }

        if (tdb_lock_nonblock(ctdb_db->ltdb->tdb, -1, F_WRLCK) != 0) {
                tdb_chainunlock(ctdb_db->ltdb->tdb, key);
                free(data2.dptr);
                return -1;
        }

        if (tdb_delete(ctdb_db->ltdb->tdb, key) != 0) {
                tdb_unlock(ctdb_db->ltdb->tdb, -1, F_WRLCK);
                tdb_chainunlock(ctdb_db->ltdb->tdb, key);
                DEBUG(DEBUG_INFO,(__location__ " Failed to delete record\n"));
                free(data2.dptr);
                return -1;
        }

        tdb_unlock(ctdb_db->ltdb->tdb, -1, F_WRLCK);
        tdb_chainunlock(ctdb_db->ltdb->tdb, key);
        free(data2.dptr);
        return 0;
}



struct recovery_callback_state {
        struct ctdb_req_control *c;
};


/*
  called when the 'recovered' event script has finished
 */
static void ctdb_end_recovery_callback(struct ctdb_context *ctdb, int status, void *p)
{
        struct recovery_callback_state *state = talloc_get_type(p, struct recovery_callback_state);

        ctdb_enable_monitoring(ctdb);
        CTDB_INCREMENT_STAT(ctdb, num_recoveries);

        if (status != 0) {
                DEBUG(DEBUG_ERR,(__location__ " recovered event script failed (status %d)\n", status));
                if (status == -ETIME) {
                        ctdb_ban_self(ctdb);
                }
        }

        ctdb_request_control_reply(ctdb, state->c, NULL, status, NULL);
        talloc_free(state);

        gettimeofday(&ctdb->last_recovery_finished, NULL);

        if (ctdb->runstate == CTDB_RUNSTATE_FIRST_RECOVERY) {
                ctdb_set_runstate(ctdb, CTDB_RUNSTATE_STARTUP);
        }
}

/*
  recovery has finished
 */
int32_t ctdb_control_end_recovery(struct ctdb_context *ctdb, 
                                struct ctdb_req_control *c,
                                bool *async_reply)
{
        int ret;
        struct recovery_callback_state *state;

        DEBUG(DEBUG_NOTICE,("Recovery has finished\n"));

        ctdb_persistent_finish_trans3_commits(ctdb);

        state = talloc(ctdb, struct recovery_callback_state);
        CTDB_NO_MEMORY(ctdb, state);

        state->c    = c;

        ctdb_disable_monitoring(ctdb);

        ret = ctdb_event_script_callback(ctdb, state,
                                         ctdb_end_recovery_callback, 
                                         state, 
                                         CTDB_EVENT_RECOVERED, "%s", "");

        if (ret != 0) {
                ctdb_enable_monitoring(ctdb);

                DEBUG(DEBUG_ERR,(__location__ " Failed to end recovery\n"));
                talloc_free(state);
                return -1;
        }

        /* tell the control that we will be reply asynchronously */
        state->c    = talloc_steal(state, c);
        *async_reply = true;
        return 0;
}

/*
  called when the 'startrecovery' event script has finished
 */
static void ctdb_start_recovery_callback(struct ctdb_context *ctdb, int status, void *p)
{
        struct recovery_callback_state *state = talloc_get_type(p, struct recovery_callback_state);

        if (status != 0) {
                DEBUG(DEBUG_ERR,(__location__ " startrecovery event script failed (status %d)\n", status));
        }

        ctdb_request_control_reply(ctdb, state->c, NULL, status, NULL);
        talloc_free(state);
}

/*
  run the startrecovery eventscript
 */
int32_t ctdb_control_start_recovery(struct ctdb_context *ctdb, 
                                struct ctdb_req_control *c,
                                bool *async_reply)
{
        int ret;
        struct recovery_callback_state *state;

        DEBUG(DEBUG_NOTICE,(__location__ " startrecovery eventscript has been invoked\n"));
        gettimeofday(&ctdb->last_recovery_started, NULL);

        state = talloc(ctdb, struct recovery_callback_state);
        CTDB_NO_MEMORY(ctdb, state);

        state->c    = talloc_steal(state, c);

        ctdb_disable_monitoring(ctdb);

        ret = ctdb_event_script_callback(ctdb, state,
                                         ctdb_start_recovery_callback, 
                                         state,
                                         CTDB_EVENT_START_RECOVERY,
                                         "%s", "");

        if (ret != 0) {
                DEBUG(DEBUG_ERR,(__location__ " Failed to start recovery\n"));
                talloc_free(state);
                return -1;
        }

        /* tell the control that we will be reply asynchronously */
        *async_reply = true;
        return 0;
}

/*
 try to delete all these records as part of the vacuuming process
 and return the records we failed to delete
*/
int32_t ctdb_control_try_delete_records(struct ctdb_context *ctdb, TDB_DATA indata, TDB_DATA *outdata)
{
        struct ctdb_marshall_buffer *reply = (struct ctdb_marshall_buffer *)indata.dptr;
        struct ctdb_db_context *ctdb_db;
        int i;
        struct ctdb_rec_data *rec;
        struct ctdb_marshall_buffer *records;

        if (indata.dsize < offsetof(struct ctdb_marshall_buffer, data)) {
                DEBUG(DEBUG_ERR,(__location__ " invalid data in try_delete_records\n"));
                return -1;
        }

        ctdb_db = find_ctdb_db(ctdb, reply->db_id);
        if (!ctdb_db) {
                DEBUG(DEBUG_ERR,(__location__ " Unknown db 0x%08x\n", reply->db_id));
                return -1;
        }


        DEBUG(DEBUG_DEBUG,("starting try_delete_records of %u records for dbid 0x%x\n",
                 reply->count, reply->db_id));


        /* create a blob to send back the records we couldnt delete */  
        records = (struct ctdb_marshall_buffer *)
                        talloc_zero_size(outdata, 
                                    offsetof(struct ctdb_marshall_buffer, data));
        if (records == NULL) {
                DEBUG(DEBUG_ERR,(__location__ " Out of memory\n"));
                return -1;
        }
        records->db_id = ctdb_db->db_id;


        rec = (struct ctdb_rec_data *)&reply->data[0];
        for (i=0;i<reply->count;i++) {
                TDB_DATA key, data;

                key.dptr = &rec->data[0];
                key.dsize = rec->keylen;
                data.dptr = &rec->data[key.dsize];
                data.dsize = rec->datalen;

                if (data.dsize < sizeof(struct ctdb_ltdb_header)) {
                        DEBUG(DEBUG_CRIT,(__location__ " bad ltdb record in indata\n"));
                        return -1;
                }

                /* If we cant delete the record we must add it to the reply
                   so the lmaster knows it may not purge this record
                */
                if (delete_tdb_record(ctdb, ctdb_db, rec) != 0) {
                        size_t old_size;
                        struct ctdb_ltdb_header *hdr;

                        hdr = (struct ctdb_ltdb_header *)data.dptr;
                        data.dptr += sizeof(*hdr);
                        data.dsize -= sizeof(*hdr);

                        DEBUG(DEBUG_INFO, (__location__ " Failed to vacuum delete record with hash 0x%08x\n", ctdb_hash(&key)));

                        old_size = talloc_get_size(records);
                        records = talloc_realloc_size(outdata, records, old_size + rec->length);
                        if (records == NULL) {
                                DEBUG(DEBUG_ERR,(__location__ " Failed to expand\n"));
                                return -1;
                        }
                        records->count++;
                        memcpy(old_size+(uint8_t *)records, rec, rec->length);
                } 

                rec = (struct ctdb_rec_data *)(rec->length + (uint8_t *)rec);
        }           


        *outdata = ctdb_marshall_finish(records);

        return 0;
}

/**
 * Store a record as part of the vacuum process:
 * This is called from the RECEIVE_RECORD control which
 * the lmaster uses to send the current empty copy
 * to all nodes for storing, before it lets the other
 * nodes delete the records in the second phase with
 * the TRY_DELETE_RECORDS control.
 *
 * Only store if we are not lmaster or dmaster, and our
 * rsn is <= the provided rsn. Use non-blocking locks.
 *
 * return 0 if the record was successfully stored.
 * return !0 if the record still exists in the tdb after returning.
 */
static int store_tdb_record(struct ctdb_context *ctdb,
                            struct ctdb_db_context *ctdb_db,
                            struct ctdb_rec_data *rec)
{
        TDB_DATA key, data, data2;
        struct ctdb_ltdb_header *hdr, *hdr2;
        int ret;

        key.dsize = rec->keylen;
        key.dptr = &rec->data[0];
        data.dsize = rec->datalen;
        data.dptr = &rec->data[rec->keylen];

        if (ctdb_lmaster(ctdb, &key) == ctdb->pnn) {
                DEBUG(DEBUG_INFO, (__location__ " Called store_tdb_record "
                                   "where we are lmaster\n"));
                return -1;
        }

        if (data.dsize != sizeof(struct ctdb_ltdb_header)) {
                DEBUG(DEBUG_ERR, (__location__ " Bad record size\n"));
                return -1;
        }

        hdr = (struct ctdb_ltdb_header *)data.dptr;

        /* use a non-blocking lock */
        if (tdb_chainlock_nonblock(ctdb_db->ltdb->tdb, key) != 0) {
                DEBUG(DEBUG_INFO, (__location__ " Failed to lock chain in non-blocking mode\n"));
                return -1;
        }

        data2 = tdb_fetch(ctdb_db->ltdb->tdb, key);
        if (data2.dptr == NULL || data2.dsize < sizeof(struct ctdb_ltdb_header)) {
                if (tdb_store(ctdb_db->ltdb->tdb, key, data, 0) == -1) {
                        DEBUG(DEBUG_ERR, (__location__ "Failed to store record\n"));
                        ret = -1;
                        goto done;
                }
                DEBUG(DEBUG_INFO, (__location__ " Stored record\n"));
                ret = 0;
                goto done;
        }

        hdr2 = (struct ctdb_ltdb_header *)data2.dptr;

        if (hdr2->rsn > hdr->rsn) {
                DEBUG(DEBUG_INFO, (__location__ " Skipping record with "
                                   "rsn=%llu - called with rsn=%llu\n",
                                   (unsigned long long)hdr2->rsn,
                                   (unsigned long long)hdr->rsn));
                ret = -1;
                goto done;
        }

        /* do not allow vacuuming of records that have readonly flags set. */
        if (hdr->flags & CTDB_REC_RO_FLAGS) {
                DEBUG(DEBUG_INFO,(__location__ " Skipping record with readonly "
                                  "flags set\n"));
                ret = -1;
                goto done;
        }
        if (hdr2->flags & CTDB_REC_RO_FLAGS) {
                DEBUG(DEBUG_INFO,(__location__ " Skipping record with readonly "
                                  "flags set\n"));
                ret = -1;
                goto done;
        }

        if (hdr2->dmaster == ctdb->pnn) {
                DEBUG(DEBUG_INFO, (__location__ " Attempted to store record "
                                   "where we are the dmaster\n"));
                ret = -1;
                goto done;
        }

        if (tdb_store(ctdb_db->ltdb->tdb, key, data, 0) != 0) {
                DEBUG(DEBUG_INFO,(__location__ " Failed to store record\n"));
                ret = -1;
                goto done;
        }

        ret = 0;

done:
        tdb_chainunlock(ctdb_db->ltdb->tdb, key);
        free(data2.dptr);
        return  ret;
}



/**
 * Try to store all these records as part of the vacuuming process
 * and return the records we failed to store.
 */
int32_t ctdb_control_receive_records(struct ctdb_context *ctdb,
                                     TDB_DATA indata, TDB_DATA *outdata)
{
        struct ctdb_marshall_buffer *reply = (struct ctdb_marshall_buffer *)indata.dptr;
        struct ctdb_db_context *ctdb_db;
        int i;
        struct ctdb_rec_data *rec;
        struct ctdb_marshall_buffer *records;

        if (indata.dsize < offsetof(struct ctdb_marshall_buffer, data)) {
                DEBUG(DEBUG_ERR,
                      (__location__ " invalid data in receive_records\n"));
                return -1;
        }

        ctdb_db = find_ctdb_db(ctdb, reply->db_id);
        if (!ctdb_db) {
                DEBUG(DEBUG_ERR, (__location__ " Unknown db 0x%08x\n",
                                  reply->db_id));
                return -1;
        }

        DEBUG(DEBUG_DEBUG, ("starting receive_records of %u records for "
                            "dbid 0x%x\n", reply->count, reply->db_id));

        /* create a blob to send back the records we could not store */
        records = (struct ctdb_marshall_buffer *)
                        talloc_zero_size(outdata,
                                offsetof(struct ctdb_marshall_buffer, data));
        if (records == NULL) {
                DEBUG(DEBUG_ERR, (__location__ " Out of memory\n"));
                return -1;
        }
        records->db_id = ctdb_db->db_id;

        rec = (struct ctdb_rec_data *)&reply->data[0];
        for (i=0; i<reply->count; i++) {
                TDB_DATA key, data;

                key.dptr = &rec->data[0];
                key.dsize = rec->keylen;
                data.dptr = &rec->data[key.dsize];
                data.dsize = rec->datalen;

                if (data.dsize < sizeof(struct ctdb_ltdb_header)) {
                        DEBUG(DEBUG_CRIT, (__location__ " bad ltdb record "
                                           "in indata\n"));
                        return -1;
                }

                /*
                 * If we can not store the record we must add it to the reply
                 * so the lmaster knows it may not purge this record.
                 */
                if (store_tdb_record(ctdb, ctdb_db, rec) != 0) {
                        size_t old_size;
                        struct ctdb_ltdb_header *hdr;

                        hdr = (struct ctdb_ltdb_header *)data.dptr;
                        data.dptr += sizeof(*hdr);
                        data.dsize -= sizeof(*hdr);

                        DEBUG(DEBUG_INFO, (__location__ " Failed to store "
                                           "record with hash 0x%08x in vacuum "
                                           "via RECEIVE_RECORDS\n",
                                           ctdb_hash(&key)));

                        old_size = talloc_get_size(records);
                        records = talloc_realloc_size(outdata, records,
                                                      old_size + rec->length);
                        if (records == NULL) {
                                DEBUG(DEBUG_ERR, (__location__ " Failed to "
                                                  "expand\n"));
                                return -1;
                        }
                        records->count++;
                        memcpy(old_size+(uint8_t *)records, rec, rec->length);
                }

                rec = (struct ctdb_rec_data *)(rec->length + (uint8_t *)rec);
        }

        *outdata = ctdb_marshall_finish(records);

        return 0;
}


/*
  report capabilities
 */
int32_t ctdb_control_get_capabilities(struct ctdb_context *ctdb, TDB_DATA *outdata)
{
        uint32_t *capabilities = NULL;

        capabilities = talloc(outdata, uint32_t);
        CTDB_NO_MEMORY(ctdb, capabilities);
        *capabilities = ctdb->capabilities;

        outdata->dsize = sizeof(uint32_t);
        outdata->dptr = (uint8_t *)capabilities;

        return 0;       
}

/* The recovery daemon will ping us at regular intervals.
   If we havent been pinged for a while we assume the recovery
   daemon is inoperable and we restart.
*/
static void ctdb_recd_ping_timeout(struct event_context *ev, struct timed_event *te, struct timeval t, void *p)
{
        struct ctdb_context *ctdb = talloc_get_type(p, struct ctdb_context);
        uint32_t *count = talloc_get_type(ctdb->recd_ping_count, uint32_t);

        DEBUG(DEBUG_ERR, ("Recovery daemon ping timeout. Count : %u\n", *count));

        if (*count < ctdb->tunable.recd_ping_failcount) {
                (*count)++;
                event_add_timed(ctdb->ev, ctdb->recd_ping_count, 
                        timeval_current_ofs(ctdb->tunable.recd_ping_timeout, 0),
                        ctdb_recd_ping_timeout, ctdb);
                return;
        }

        DEBUG(DEBUG_ERR, ("Final timeout for recovery daemon ping. Restarting recovery daemon. (This can be caused if the cluster filesystem has hung)\n"));

        ctdb_stop_recoverd(ctdb);
        ctdb_start_recoverd(ctdb);
}

int32_t ctdb_control_recd_ping(struct ctdb_context *ctdb)
{
        talloc_free(ctdb->recd_ping_count);

        ctdb->recd_ping_count = talloc_zero(ctdb, uint32_t);
        CTDB_NO_MEMORY(ctdb, ctdb->recd_ping_count);

        if (ctdb->tunable.recd_ping_timeout != 0) {
                event_add_timed(ctdb->ev, ctdb->recd_ping_count, 
                        timeval_current_ofs(ctdb->tunable.recd_ping_timeout, 0),
                        ctdb_recd_ping_timeout, ctdb);
        }

        return 0;
}



int32_t ctdb_control_set_recmaster(struct ctdb_context *ctdb, uint32_t opcode, TDB_DATA indata)
{
        uint32_t new_recmaster;

        CHECK_CONTROL_DATA_SIZE(sizeof(uint32_t));
        new_recmaster = ((uint32_t *)(&indata.dptr[0]))[0];

        if (ctdb->pnn != new_recmaster && ctdb->recovery_master == ctdb->pnn) {
                DEBUG(DEBUG_NOTICE,
                      ("This node (%u) is no longer the recovery master\n", ctdb->pnn));
        }

        if (ctdb->pnn == new_recmaster && ctdb->recovery_master != new_recmaster) {
                DEBUG(DEBUG_NOTICE,
                      ("This node (%u) is now the recovery master\n", ctdb->pnn));
        }

        ctdb->recovery_master = new_recmaster;
        return 0;
}


int32_t ctdb_control_stop_node(struct ctdb_context *ctdb)
{
        DEBUG(DEBUG_NOTICE, ("Stopping node\n"));
        ctdb_disable_monitoring(ctdb);
        ctdb->nodes[ctdb->pnn]->flags |= NODE_FLAGS_STOPPED;

        return 0;
}

int32_t ctdb_control_continue_node(struct ctdb_context *ctdb)
{
        DEBUG(DEBUG_NOTICE, ("Continue node\n"));
        ctdb->nodes[ctdb->pnn]->flags &= ~NODE_FLAGS_STOPPED;

        return 0;
}