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ctdbd_conn.c

/* 
   Unix SMB/CIFS implementation.
   Samba internal messaging functions
   Copyright (C) 2007 by Volker Lendecke
   Copyright (C) 2007 by Andrew Tridgell
   
   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"

#ifdef CLUSTER_SUPPORT

#include "librpc/gen_ndr/messaging.h"
#include "librpc/gen_ndr/ndr_messaging.h"

/* paths to these include files come from --with-ctdb= in configure */
#include "ctdb.h"
#include "ctdb_private.h"

struct ctdbd_connection {
      struct messaging_context *msg_ctx;
      uint32 reqid;
      uint32 our_vnn;
      uint64 rand_srvid;
      struct packet_context *pkt;
      struct fd_event *fde;
      
      void (*release_ip_handler)(const char *ip_addr, void *private_data);
      void *release_ip_priv;
};

static NTSTATUS ctdbd_control(struct ctdbd_connection *conn,
                        uint32_t vnn, uint32 opcode, 
                        uint64_t srvid, TDB_DATA data, 
                        TALLOC_CTX *mem_ctx, TDB_DATA *outdata,
                        int *cstatus);

/*
 * exit on fatal communications errors with the ctdbd daemon
 */
static void cluster_fatal(const char *why)
{
      DEBUG(0,("cluster fatal event: %s - exiting immediately\n", why));
      /* we don't use smb_panic() as we don't want to delay to write
         a core file. We need to release this process id immediately
         so that someone else can take over without getting sharing
         violations */
      _exit(0);
}

/*
 *
 */
static void ctdb_packet_dump(struct ctdb_req_header *hdr)
{
      if (DEBUGLEVEL < 10) {
            return;
      }
      DEBUGADD(10, ("len=%d, magic=%x, vers=%d, gen=%d, op=%d, reqid=%d\n",
                  (int)hdr->length, (int)hdr->ctdb_magic,
                  (int)hdr->ctdb_version, (int)hdr->generation,
                  (int)hdr->operation, (int)hdr->reqid));
}

/*
 * Register a srvid with ctdbd
 */
static NTSTATUS register_with_ctdbd(struct ctdbd_connection *conn,
                            uint64_t srvid)
{

      int cstatus;
      return ctdbd_control(conn, CTDB_CURRENT_NODE,
                       CTDB_CONTROL_REGISTER_SRVID, srvid,
                       tdb_null, NULL, NULL, &cstatus);
}

/*
 * get our vnn from the cluster
 */
static NTSTATUS get_cluster_vnn(struct ctdbd_connection *conn, uint32 *vnn)
{
      int32_t cstatus=-1;
      NTSTATUS status;
      status = ctdbd_control(conn,
                         CTDB_CURRENT_NODE, CTDB_CONTROL_GET_PNN, 0,
                         tdb_null, NULL, NULL, &cstatus);
      if (!NT_STATUS_IS_OK(status)) {
            cluster_fatal("ctdbd_control failed\n");
      }
      *vnn = (uint32_t)cstatus;
      return status;
}

uint32 ctdbd_vnn(const struct ctdbd_connection *conn)
{
      return conn->our_vnn;
}

/*
 * Get us a ctdb connection
 */

static NTSTATUS ctdbd_connect(TALLOC_CTX *mem_ctx,
                        struct packet_context **presult)
{
      struct packet_context *result;
      const char *sockname = lp_ctdbd_socket();
      struct sockaddr_un addr;
      int fd;

      if (!sockname || !*sockname) {
            sockname = CTDB_PATH;
      }

      fd = socket(AF_UNIX, SOCK_STREAM, 0);
      if (fd == -1) {
            DEBUG(3, ("Could not create socket: %s\n", strerror(errno)));
            return map_nt_error_from_unix(errno);
      }

      ZERO_STRUCT(addr);
      addr.sun_family = AF_UNIX;
      strncpy(addr.sun_path, sockname, sizeof(addr.sun_path));

      if (sys_connect(fd, (struct sockaddr *)&addr) == -1) {
            DEBUG(0, ("connect(%s) failed: %s\n", sockname,
                    strerror(errno)));
            close(fd);
            return map_nt_error_from_unix(errno);
      }

      if (!(result = packet_init(mem_ctx, fd))) {
            close(fd);
            return NT_STATUS_NO_MEMORY;
      }

      *presult = result;
      return NT_STATUS_OK;
}

/*
 * Do we have a complete ctdb packet in the queue?
 */

static bool ctdb_req_complete(const struct data_blob *data,
                        size_t *length,
                        void *private_data)
{
      uint32 msglen;

      if (data->length < sizeof(msglen)) {
            return False;
      }

      msglen = *((uint32 *)data->data);

      DEBUG(10, ("msglen = %d\n", msglen));

      if (msglen < sizeof(struct ctdb_req_header)) {
            DEBUG(0, ("Got invalid msglen: %d, expected at least %d for "
                    "the req_header\n", (int)msglen,
                    (int)sizeof(struct ctdb_req_header)));
            cluster_fatal("ctdbd protocol error\n");
      }

      if (data->length >= msglen) {
            *length = msglen;
            return True;
      }

      return False;
}

/*
 * State necessary to defer an incoming message while we are waiting for a
 * ctdb reply.
 */

struct deferred_msg_state {
      struct messaging_context *msg_ctx;
      struct messaging_rec *rec;
};

/*
 * Timed event handler for the deferred message
 */

static void deferred_message_dispatch(struct event_context *event_ctx,
                              struct timed_event *te,
                              const struct timeval *now,
                              void *private_data)
{
      struct deferred_msg_state *state = talloc_get_type_abort(
            private_data, struct deferred_msg_state);

      messaging_dispatch_rec(state->msg_ctx, state->rec);
      TALLOC_FREE(state);
      TALLOC_FREE(te);
}

struct req_pull_state {
      TALLOC_CTX *mem_ctx;
      DATA_BLOB req;
};

/*
 * Pull a ctdb request out of the incoming packet queue
 */

static NTSTATUS ctdb_req_pull(const struct data_blob *data,
                        void *private_data)
{
      struct req_pull_state *state = (struct req_pull_state *)private_data;

      state->req = data_blob_talloc(state->mem_ctx, data->data,
                              data->length);
      if (state->req.data == NULL) {
            return NT_STATUS_NO_MEMORY;
      }
      return NT_STATUS_OK;
}

/*
 * Fetch a messaging_rec from an incoming ctdb style message
 */

static struct messaging_rec *ctdb_pull_messaging_rec(TALLOC_CTX *mem_ctx,
                                         size_t overall_length,
                                         struct ctdb_req_message *msg)
{
      struct messaging_rec *result;
      DATA_BLOB blob;
      enum ndr_err_code ndr_err;

      if ((overall_length < offsetof(struct ctdb_req_message, data))
          || (overall_length
            < offsetof(struct ctdb_req_message, data) + msg->datalen)) {

            cluster_fatal("got invalid msg length");
      }

      if (!(result = TALLOC_P(mem_ctx, struct messaging_rec))) {
            DEBUG(0, ("talloc failed\n"));
            return NULL;
      }

      blob = data_blob_const(msg->data, msg->datalen);

      ndr_err = ndr_pull_struct_blob(
            &blob, result, result,
            (ndr_pull_flags_fn_t)ndr_pull_messaging_rec);

      if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
            DEBUG(0, ("ndr_pull_struct_blob failed: %s\n",
                    ndr_errstr(ndr_err)));
            TALLOC_FREE(result);
            return NULL;
      }

      if (DEBUGLEVEL >= 10) {
            DEBUG(10, ("ctdb_pull_messaging_rec:\n"));
            NDR_PRINT_DEBUG(messaging_rec, result);
      }

      return result;
}

/*
 * Read a full ctdbd request. If we have a messaging context, defer incoming
 * messages that might come in between.
 */

static NTSTATUS ctdb_read_req(struct ctdbd_connection *conn, uint32 reqid,
                        TALLOC_CTX *mem_ctx, void *result)
{
      struct ctdb_req_header *hdr;
      struct req_pull_state state;
      NTSTATUS status;

 again:

      status = packet_fd_read_sync(conn->pkt);

      if (NT_STATUS_EQUAL(status, NT_STATUS_NETWORK_BUSY)) {
            /* EAGAIN */
            goto again;
      } else if (NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
            /* EAGAIN */
            goto again;
      }

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, ("packet_fd_read failed: %s\n", nt_errstr(status)));
            cluster_fatal("ctdbd died\n");
      }

 next_pkt:

      ZERO_STRUCT(state);
      state.mem_ctx = mem_ctx;

      if (!packet_handler(conn->pkt, ctdb_req_complete, ctdb_req_pull,
                      &state, &status)) {
            /*
             * Not enough data
             */
            DEBUG(10, ("not enough data from ctdb socket, retrying\n"));
            goto again;
      }

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, ("Could not read packet: %s\n", nt_errstr(status)));
            cluster_fatal("ctdbd died\n");
      }

      hdr = (struct ctdb_req_header *)state.req.data;

      DEBUG(10, ("Received ctdb packet\n"));
      ctdb_packet_dump(hdr);

      if (hdr->operation == CTDB_REQ_MESSAGE) {
            struct timed_event *evt;
            struct deferred_msg_state *msg_state;
            struct ctdb_req_message *msg = (struct ctdb_req_message *)hdr;

            if (conn->msg_ctx == NULL) {
                  DEBUG(1, ("Got a message without having a msg ctx, "
                          "dropping msg %llu\n",
                          (long long unsigned)msg->srvid));
                  goto next_pkt;
            }
            
            if ((conn->release_ip_handler != NULL)
                && (msg->srvid == CTDB_SRVID_RELEASE_IP)) {
                  /* must be dispatched immediately */
                  DEBUG(10, ("received CTDB_SRVID_RELEASE_IP\n"));
                  conn->release_ip_handler((const char *)msg->data,
                                     conn->release_ip_priv);
                  TALLOC_FREE(hdr);
                  goto next_pkt;
            }

            if (!(msg_state = TALLOC_P(NULL, struct deferred_msg_state))) {
                  DEBUG(0, ("talloc failed\n"));
                  TALLOC_FREE(hdr);
                  goto next_pkt;
            }

            if (!(msg_state->rec = ctdb_pull_messaging_rec(
                        msg_state, state.req.length, msg))) {
                  DEBUG(0, ("ctdbd_pull_messaging_rec failed\n"));
                  TALLOC_FREE(msg_state);
                  TALLOC_FREE(hdr);
                  goto next_pkt;
            }

            TALLOC_FREE(hdr);

            msg_state->msg_ctx = conn->msg_ctx;
            
            /*
             * We're waiting for a call reply, but an async message has
             * crossed. Defer dispatching to the toplevel event loop.
             */
            evt = event_add_timed(conn->msg_ctx->event_ctx,
                              conn->msg_ctx->event_ctx,
                              timeval_zero(),
                              "deferred_message_dispatch",
                              deferred_message_dispatch,
                              msg_state);
            if (evt == NULL) {
                  DEBUG(0, ("event_add_timed failed\n"));
                  TALLOC_FREE(msg_state);
                  TALLOC_FREE(hdr);
                  goto next_pkt;
            }
            
            goto next_pkt;
      }

      if (hdr->reqid != reqid) {
            /* we got the wrong reply */
            DEBUG(0,("Discarding mismatched ctdb reqid %u should have "
                   "been %u\n", hdr->reqid, reqid));
            TALLOC_FREE(hdr);
            goto again;
      }

      *((void **)result) = talloc_move(mem_ctx, &hdr);

      return NT_STATUS_OK;
}

/*
 * Get us a ctdbd connection
 */

NTSTATUS ctdbd_init_connection(TALLOC_CTX *mem_ctx,
                         struct ctdbd_connection **pconn)
{
      struct ctdbd_connection *conn;
      NTSTATUS status;

      if (!(conn = TALLOC_ZERO_P(mem_ctx, struct ctdbd_connection))) {
            DEBUG(0, ("talloc failed\n"));
            return NT_STATUS_NO_MEMORY;
      }

      status = ctdbd_connect(conn, &conn->pkt);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(10, ("ctdbd_connect failed: %s\n", nt_errstr(status)));
            goto fail;
      }

      status = get_cluster_vnn(conn, &conn->our_vnn);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(10, ("get_cluster_vnn failed: %s\n", nt_errstr(status)));
            goto fail;
      }

      generate_random_buffer((unsigned char *)&conn->rand_srvid,
                         sizeof(conn->rand_srvid));

      status = register_with_ctdbd(conn, conn->rand_srvid);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(5, ("Could not register random srvid: %s\n",
                    nt_errstr(status)));
            goto fail;
      }

      *pconn = conn;
      return NT_STATUS_OK;

 fail:
      TALLOC_FREE(conn);
      return status;
}

/*
 * Get us a ctdbd connection and register us as a process
 */

NTSTATUS ctdbd_messaging_connection(TALLOC_CTX *mem_ctx,
                            struct ctdbd_connection **pconn)
{
        struct ctdbd_connection *conn;
      NTSTATUS status;

      status = ctdbd_init_connection(mem_ctx, &conn);

      if (!NT_STATUS_IS_OK(status)) {
            return status;
      }

      status = register_with_ctdbd(conn, (uint64_t)sys_getpid());
      if (!NT_STATUS_IS_OK(status)) {
            goto fail;
      }

      status = register_with_ctdbd(conn, MSG_SRVID_SAMBA);
      if (!NT_STATUS_IS_OK(status)) {
            goto fail;
      }

      *pconn = conn;
      return NT_STATUS_OK;

 fail:
      TALLOC_FREE(conn);
      return status;
}

/*
 * Packet handler to receive and handle a ctdb message
 */
static NTSTATUS ctdb_handle_message(const struct data_blob *data,
                            void *private_data)
{
      struct ctdbd_connection *conn = talloc_get_type_abort(
            private_data, struct ctdbd_connection);
      struct ctdb_req_message *msg;
      struct messaging_rec *msg_rec;

      msg = (struct ctdb_req_message *)data->data;

      if (msg->hdr.operation != CTDB_REQ_MESSAGE) {
            DEBUG(0, ("Received async msg of type %u, discarding\n",
                    msg->hdr.operation));
            return NT_STATUS_INVALID_PARAMETER;
      }

      if ((conn->release_ip_handler != NULL)
          && (msg->srvid == CTDB_SRVID_RELEASE_IP)) {
            /* must be dispatched immediately */
            DEBUG(10, ("received CTDB_SRVID_RELEASE_IP\n"));
            conn->release_ip_handler((const char *)msg->data,
                               conn->release_ip_priv);
            return NT_STATUS_OK;
      }

      SMB_ASSERT(conn->msg_ctx != NULL);

      if (msg->srvid == CTDB_SRVID_RECONFIGURE) {
            DEBUG(0,("Got cluster reconfigure message\n"));
            /*
             * when the cluster is reconfigured, we need to clean the brl
             * database
             */
            messaging_send(conn->msg_ctx, procid_self(),
                         MSG_SMB_BRL_VALIDATE, &data_blob_null);

            /*
             * it's possible that we have just rejoined the cluster after
             * an outage. In that case our pending locks could have been
             * removed from the lockdb, so retry them once more
             */
            message_send_all(conn->msg_ctx, MSG_SMB_UNLOCK, NULL, 0, NULL);

            return NT_STATUS_OK;
            
      }

      /* only messages to our pid or the broadcast are valid here */
      if (msg->srvid != sys_getpid() && msg->srvid != MSG_SRVID_SAMBA) {
            DEBUG(0,("Got unexpected message with srvid=%llu\n", 
                   (unsigned long long)msg->srvid));
            return NT_STATUS_OK;
      }

      if (!(msg_rec = ctdb_pull_messaging_rec(NULL, data->length, msg))) {
            DEBUG(10, ("ctdb_pull_messaging_rec failed\n"));
            return NT_STATUS_NO_MEMORY;
      }

      messaging_dispatch_rec(conn->msg_ctx, msg_rec);

      TALLOC_FREE(msg_rec);
      return NT_STATUS_OK;
}

/*
 * The ctdbd socket is readable asynchronuously
 */

static void ctdbd_socket_handler(struct event_context *event_ctx,
                         struct fd_event *event,
                         uint16 flags,
                         void *private_data)
{
      struct ctdbd_connection *conn = talloc_get_type_abort(
            private_data, struct ctdbd_connection);

      NTSTATUS status;

      status = packet_fd_read(conn->pkt);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, ("packet_fd_read failed: %s\n", nt_errstr(status)));
            cluster_fatal("ctdbd died\n");
      }

      while (packet_handler(conn->pkt, ctdb_req_complete,
                        ctdb_handle_message, conn, &status)) {
            if (!NT_STATUS_IS_OK(status)) {
                  DEBUG(10, ("could not handle incoming message: %s\n",
                           nt_errstr(status)));
            }
      }
}

/*
 * Prepare a ctdbd connection to receive messages
 */

NTSTATUS ctdbd_register_msg_ctx(struct ctdbd_connection *conn,
                        struct messaging_context *msg_ctx)
{
      SMB_ASSERT(conn->msg_ctx == NULL);
      SMB_ASSERT(conn->fde == NULL);

      if (!(conn->fde = event_add_fd(msg_ctx->event_ctx, conn,
                               packet_get_fd(conn->pkt),
                               EVENT_FD_READ,
                               ctdbd_socket_handler,
                               conn))) {
            DEBUG(0, ("event_add_fd failed\n"));
            return NT_STATUS_NO_MEMORY;
      }

      conn->msg_ctx = msg_ctx;

      return NT_STATUS_OK;
}

/*
 * Send a messaging message across a ctdbd
 */

NTSTATUS ctdbd_messaging_send(struct ctdbd_connection *conn,
                        uint32 dst_vnn, uint64 dst_srvid,
                        struct messaging_rec *msg)
{
      struct ctdb_req_message r;
      TALLOC_CTX *mem_ctx;
      DATA_BLOB blob;
      NTSTATUS status;
      enum ndr_err_code ndr_err;

      if (!(mem_ctx = talloc_init("ctdbd_messaging_send"))) {
            DEBUG(0, ("talloc failed\n"));
            return NT_STATUS_NO_MEMORY;
      }

      ndr_err = ndr_push_struct_blob(
            &blob, mem_ctx, msg,
            (ndr_push_flags_fn_t)ndr_push_messaging_rec);

      if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
            DEBUG(0, ("ndr_push_struct_blob failed: %s\n",
                    ndr_errstr(ndr_err)));
            status = ndr_map_error2ntstatus(ndr_err);
            goto fail;
      }

      r.hdr.length = offsetof(struct ctdb_req_message, data) + blob.length;
      r.hdr.ctdb_magic = CTDB_MAGIC;
      r.hdr.ctdb_version = CTDB_VERSION;
      r.hdr.generation = 1;
      r.hdr.operation  = CTDB_REQ_MESSAGE;
      r.hdr.destnode   = dst_vnn;
      r.hdr.srcnode    = conn->our_vnn;
      r.hdr.reqid      = 0;
      r.srvid          = dst_srvid;
      r.datalen        = blob.length;

      DEBUG(10, ("ctdbd_messaging_send: Sending ctdb packet\n"));
      ctdb_packet_dump(&r.hdr);

      status = packet_send(
            conn->pkt, 2,
            data_blob_const(&r, offsetof(struct ctdb_req_message, data)),
            blob);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, ("packet_send failed: %s\n", nt_errstr(status)));
            goto fail;
      }

      status = packet_flush(conn->pkt);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(3, ("write to ctdbd failed: %s\n", nt_errstr(status)));
            cluster_fatal("cluster dispatch daemon msg write error\n");
      }

      status = NT_STATUS_OK;
 fail:
      TALLOC_FREE(mem_ctx);
      return status;
}

/*
 * send/recv a generic ctdb control message
 */
static NTSTATUS ctdbd_control(struct ctdbd_connection *conn,
                        uint32_t vnn, uint32 opcode, 
                        uint64_t srvid, TDB_DATA data, 
                        TALLOC_CTX *mem_ctx, TDB_DATA *outdata,
                        int *cstatus)
{
      struct ctdb_req_control req;
      struct ctdb_reply_control *reply = NULL;
      struct ctdbd_connection *new_conn = NULL;
      NTSTATUS status;

      if (conn == NULL) {
            status = ctdbd_init_connection(NULL, &new_conn);

            if (!NT_STATUS_IS_OK(status)) {
                  DEBUG(10, ("Could not init temp connection: %s\n",
                           nt_errstr(status)));
                  goto fail;
            }

            conn = new_conn;
      }

      ZERO_STRUCT(req);
      req.hdr.length = offsetof(struct ctdb_req_control, data) + data.dsize;
      req.hdr.ctdb_magic   = CTDB_MAGIC;
      req.hdr.ctdb_version = CTDB_VERSION;
      req.hdr.operation    = CTDB_REQ_CONTROL;
      req.hdr.reqid        = ++conn->reqid;
      req.hdr.destnode     = vnn;
      req.opcode           = opcode;
      req.srvid            = srvid;
      req.datalen          = data.dsize;

      DEBUG(10, ("ctdbd_control: Sending ctdb packet\n"));
      ctdb_packet_dump(&req.hdr);

      status = packet_send(
            conn->pkt, 2,
            data_blob_const(&req, offsetof(struct ctdb_req_control, data)),
            data_blob_const(data.dptr, data.dsize));

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(3, ("packet_send failed: %s\n", nt_errstr(status)));
            goto fail;
      }

      status = packet_flush(conn->pkt);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(3, ("write to ctdbd failed: %s\n", nt_errstr(status)));
            cluster_fatal("cluster dispatch daemon control write error\n");
      }

      status = ctdb_read_req(conn, req.hdr.reqid, NULL, (void *)&reply);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(10, ("ctdb_read_req failed: %s\n", nt_errstr(status)));
            goto fail;
      }

      if (reply->hdr.operation != CTDB_REPLY_CONTROL) {
            DEBUG(0, ("received invalid reply\n"));
            goto fail;
      }

      if (outdata) {
            if (!(outdata->dptr = (uint8 *)talloc_memdup(
                        mem_ctx, reply->data, reply->datalen))) {
                  TALLOC_FREE(reply);
                  return NT_STATUS_NO_MEMORY;
            }
            outdata->dsize = reply->datalen;
      }
      if (cstatus) {
            (*cstatus) = reply->status;
      }

      status = NT_STATUS_OK;

 fail:
      TALLOC_FREE(new_conn);
      TALLOC_FREE(reply);
      return status;
}

/*
 * see if a remote process exists
 */
bool ctdbd_process_exists(struct ctdbd_connection *conn, uint32 vnn, pid_t pid)
{
      NTSTATUS status;
      TDB_DATA data;
      int32_t cstatus;

      data.dptr = (uint8_t*)&pid;
      data.dsize = sizeof(pid);

      status = ctdbd_control(conn, vnn, CTDB_CONTROL_PROCESS_EXISTS, 0,
                         data, NULL, NULL, &cstatus);
      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, (__location__ " ctdb_control for process_exists "
                    "failed\n"));
            return False;
      }

      return cstatus == 0;
}

/*
 * Get a db path
 */
char *ctdbd_dbpath(struct ctdbd_connection *conn,
               TALLOC_CTX *mem_ctx, uint32_t db_id)
{
      NTSTATUS status;
      TDB_DATA data;
      int32_t cstatus;

      data.dptr = (uint8_t*)&db_id;
      data.dsize = sizeof(db_id);

      status = ctdbd_control(conn, CTDB_CURRENT_NODE,
                         CTDB_CONTROL_GETDBPATH, 0, data, 
                         mem_ctx, &data, &cstatus);
      if (!NT_STATUS_IS_OK(status) || cstatus != 0) {
            DEBUG(0,(__location__ " ctdb_control for getdbpath failed\n"));
            return NULL;
      }

      return (char *)data.dptr;
}

/*
 * attach to a ctdb database
 */
NTSTATUS ctdbd_db_attach(struct ctdbd_connection *conn,
                   const char *name, uint32_t *db_id, int tdb_flags)
{
      NTSTATUS status;
      TDB_DATA data;
      int32_t cstatus;

      data.dptr = (uint8_t*)name;
      data.dsize = strlen(name)+1;

      status = ctdbd_control(conn, CTDB_CURRENT_NODE,
                         CTDB_CONTROL_DB_ATTACH, 0, data, 
                         NULL, &data, &cstatus);
      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, (__location__ " ctdb_control for db_attach "
                    "failed: %s\n", nt_errstr(status)));
            return status;
      }

      if (cstatus != 0 || data.dsize != sizeof(uint32_t)) {
            DEBUG(0,(__location__ " ctdb_control for db_attach failed\n"));
            return NT_STATUS_INTERNAL_ERROR;
      }

      *db_id = *(uint32_t *)data.dptr;
      talloc_free(data.dptr);

      if (!(tdb_flags & TDB_SEQNUM)) {
            return NT_STATUS_OK;
      }

      data.dptr = (uint8_t *)db_id;
      data.dsize = sizeof(*db_id);

      status = ctdbd_control(conn, CTDB_CURRENT_NODE,
                         CTDB_CONTROL_ENABLE_SEQNUM, 0, data, 
                         NULL, NULL, &cstatus);
      if (!NT_STATUS_IS_OK(status) || cstatus != 0) {
            DEBUG(0,(__location__ " ctdb_control for enable seqnum "
                   "failed\n"));
            return NT_STATUS_IS_OK(status) ? NT_STATUS_INTERNAL_ERROR :
                  status;
      }

      return NT_STATUS_OK;
}

/*
 * force the migration of a record to this node
 */
NTSTATUS ctdbd_migrate(struct ctdbd_connection *conn, uint32 db_id,
                   TDB_DATA key)
{
      struct ctdb_req_call req;
      struct ctdb_reply_call *reply;
      NTSTATUS status;

      ZERO_STRUCT(req);
      
      req.hdr.length = offsetof(struct ctdb_req_call, data) + key.dsize;
      req.hdr.ctdb_magic   = CTDB_MAGIC;
      req.hdr.ctdb_version = CTDB_VERSION;
      req.hdr.operation    = CTDB_REQ_CALL;
      req.hdr.reqid        = ++conn->reqid;
      req.flags            = CTDB_IMMEDIATE_MIGRATION;
      req.callid           = CTDB_NULL_FUNC;
      req.db_id            = db_id;
      req.keylen           = key.dsize;

      DEBUG(10, ("ctdbd_migrate: Sending ctdb packet\n"));
      ctdb_packet_dump(&req.hdr);

      status = packet_send(
            conn->pkt, 2,
            data_blob_const(&req, offsetof(struct ctdb_req_call, data)),
            data_blob_const(key.dptr, key.dsize));

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(3, ("packet_send failed: %s\n", nt_errstr(status)));
            return status;
      }

      status = packet_flush(conn->pkt);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(3, ("write to ctdbd failed: %s\n", nt_errstr(status)));
            cluster_fatal("cluster dispatch daemon control write error\n");
      }

      status = ctdb_read_req(conn, req.hdr.reqid, NULL, (void *)&reply);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, ("ctdb_read_req failed: %s\n", nt_errstr(status)));
            goto fail;
      }

      if (reply->hdr.operation != CTDB_REPLY_CALL) {
            DEBUG(0, ("received invalid reply\n"));
            status = NT_STATUS_INTERNAL_ERROR;
            goto fail;
      }

      status = NT_STATUS_OK;
 fail:

      TALLOC_FREE(reply);
      return status;
}

/*
 * remotely fetch a record without locking it or forcing a migration
 */
NTSTATUS ctdbd_fetch(struct ctdbd_connection *conn, uint32 db_id,
                 TDB_DATA key, TALLOC_CTX *mem_ctx, TDB_DATA *data)
{
      struct ctdb_req_call req;
      struct ctdb_reply_call *reply;
      NTSTATUS status;

      ZERO_STRUCT(req);
      
      req.hdr.length = offsetof(struct ctdb_req_call, data) + key.dsize;
      req.hdr.ctdb_magic   = CTDB_MAGIC;
      req.hdr.ctdb_version = CTDB_VERSION;
      req.hdr.operation    = CTDB_REQ_CALL;
      req.hdr.reqid        = ++conn->reqid;
      req.flags            = 0;
      req.callid           = CTDB_FETCH_FUNC;
      req.db_id            = db_id;
      req.keylen           = key.dsize;

      status = packet_send(
            conn->pkt, 2,
            data_blob_const(&req, offsetof(struct ctdb_req_call, data)),
            data_blob_const(key.dptr, key.dsize));

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(3, ("packet_send failed: %s\n", nt_errstr(status)));
            return status;
      }

      status = packet_flush(conn->pkt);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(3, ("write to ctdbd failed: %s\n", nt_errstr(status)));
            cluster_fatal("cluster dispatch daemon control write error\n");
      }

      status = ctdb_read_req(conn, req.hdr.reqid, NULL, (void *)&reply);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, ("ctdb_read_req failed: %s\n", nt_errstr(status)));
            goto fail;
      }

      if (reply->hdr.operation != CTDB_REPLY_CALL) {
            DEBUG(0, ("received invalid reply\n"));
            status = NT_STATUS_INTERNAL_ERROR;
            goto fail;
      }

      data->dsize = reply->datalen;
      if (data->dsize == 0) {
            data->dptr = NULL;
            goto done;
      }

      data->dptr = (uint8 *)talloc_memdup(mem_ctx, &reply->data[0],
                                  reply->datalen);
      if (data->dptr == NULL) {
            DEBUG(0, ("talloc failed\n"));
            status = NT_STATUS_NO_MEMORY;
            goto fail;
      }

 done:
      status = NT_STATUS_OK;
 fail:
      TALLOC_FREE(reply);
      return status;
}

struct ctdbd_traverse_state {
      void (*fn)(TDB_DATA key, TDB_DATA data, void *private_data);
      void *private_data;
};

/*
 * Handle a traverse record coming in on the ctdbd connection
 */

static NTSTATUS ctdb_traverse_handler(const struct data_blob *blob,
                              void *private_data)
{
      struct ctdbd_traverse_state *state =
            (struct ctdbd_traverse_state *)private_data;

      struct ctdb_req_message *m;
      struct ctdb_rec_data *d;
      TDB_DATA key, data;

      m = (struct ctdb_req_message *)blob->data;

      if (blob->length < sizeof(*m) || m->hdr.length != blob->length) {
            DEBUG(0, ("Got invalid message of length %d\n",
                    (int)blob->length));
            return NT_STATUS_UNEXPECTED_IO_ERROR;
      }

      d = (struct ctdb_rec_data *)&m->data[0];
      if (m->datalen < sizeof(uint32_t) || m->datalen != d->length) {
            DEBUG(0, ("Got invalid traverse data of length %d\n",
                    (int)m->datalen));
            return NT_STATUS_UNEXPECTED_IO_ERROR;
      }

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

      if (key.dsize == 0 && data.dsize == 0) {
            /* end of traverse */
            return NT_STATUS_END_OF_FILE;
      }

      if (data.dsize < sizeof(struct ctdb_ltdb_header)) {
            DEBUG(0, ("Got invalid ltdb header length %d\n",
                    (int)data.dsize));
            return NT_STATUS_UNEXPECTED_IO_ERROR;
      }
      data.dsize -= sizeof(struct ctdb_ltdb_header);
      data.dptr += sizeof(struct ctdb_ltdb_header);

      if (state->fn) {
            state->fn(key, data, state->private_data);
      }

      return NT_STATUS_OK;
}

/*
  Traverse a ctdb database. This uses a kind-of hackish way to open a second
  connection to ctdbd to avoid the hairy recursive and async problems with
  everything in-line.
*/

NTSTATUS ctdbd_traverse(uint32 db_id,
                  void (*fn)(TDB_DATA key, TDB_DATA data,
                           void *private_data),
                  void *private_data)
{
      struct ctdbd_connection *conn;
      NTSTATUS status;

      TDB_DATA data;
      struct ctdb_traverse_start t;
      int cstatus;
      struct ctdbd_traverse_state state;

      status = ctdbd_init_connection(NULL, &conn);

      t.db_id = db_id;
      t.srvid = conn->rand_srvid;
      t.reqid = ++conn->reqid;

      data.dptr = (uint8_t *)&t;
      data.dsize = sizeof(t);

      status = ctdbd_control(conn, CTDB_CURRENT_NODE,
                         CTDB_CONTROL_TRAVERSE_START, conn->rand_srvid,
                         data, NULL, NULL, &cstatus);

      if (!NT_STATUS_IS_OK(status) || (cstatus != 0)) {

            DEBUG(0,("ctdbd_control failed: %s, %d\n", nt_errstr(status),
                   cstatus));

            if (NT_STATUS_IS_OK(status)) {
                  /*
                   * We need a mapping here
                   */
                  status = NT_STATUS_UNSUCCESSFUL;
            }
            goto done;
      }

      state.fn = fn;
      state.private_data = private_data;

      while (True) {

            status = NT_STATUS_OK;

            if (packet_handler(conn->pkt, ctdb_req_complete,
                           ctdb_traverse_handler, &state, &status)) {

                  if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
                        status = NT_STATUS_OK;
                        break;
                  }

                  /*
                   * There might be more in the queue
                   */
                  continue;
            }

            if (!NT_STATUS_IS_OK(status)) {
                  break;
            }

            status = packet_fd_read_sync(conn->pkt);

            if (NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) {
                  /*
                   * There might be more in the queue
                   */
                  continue;
            }

            if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
                  status = NT_STATUS_OK;
            }

            if (!NT_STATUS_IS_OK(status)) {
                  DEBUG(0, ("packet_fd_read_sync failed: %s\n", nt_errstr(status)));
                  cluster_fatal("ctdbd died\n");
            }
      }

 done:
      TALLOC_FREE(conn);
      return status;
}

/*
 * Register us as a server for a particular tcp connection
 */

NTSTATUS ctdbd_register_ips(struct ctdbd_connection *conn,
                      const struct sockaddr_in *server,
                      const struct sockaddr_in *client,
                      void (*release_ip_handler)(const char *ip_addr,
                                           void *private_data),
                      void *private_data)
{
      struct ctdb_control_tcp p;
      TDB_DATA data;
      NTSTATUS status;

      /*
       * Only one connection so far
       */
      SMB_ASSERT(conn->release_ip_handler == NULL);

      /*
       * We want to be told about IP releases
       */

      status = register_with_ctdbd(conn, CTDB_SRVID_RELEASE_IP);
      if (!NT_STATUS_IS_OK(status)) {
            return status;
      }

      p.dest = *server;
      p.src = *client;

      /*
       * inform ctdb of our tcp connection, so if IP takeover happens ctdb
       * can send an extra ack to trigger a reset for our client, so it
       * immediately reconnects
       */
      data.dptr = (uint8_t *)&p;
      data.dsize = sizeof(p);

      return ctdbd_control(conn, CTDB_CURRENT_NODE, 
                       CTDB_CONTROL_TCP_CLIENT, 
                       CTDB_CTRL_FLAG_NOREPLY, data, NULL, NULL, NULL);
}

/*
 * We want to handle reconfigure events
 */
NTSTATUS ctdbd_register_reconfigure(struct ctdbd_connection *conn)
{
      return register_with_ctdbd(conn, CTDB_SRVID_RECONFIGURE);
}

/*
  persstent store. Used when we update a record in a persistent database
 */
NTSTATUS ctdbd_persistent_store(struct ctdbd_connection *conn, uint32_t db_id, TDB_DATA key, TDB_DATA data)
{
       int cstatus=0;
       struct ctdb_rec_data *rec;
       TDB_DATA recdata;
       size_t length;
       NTSTATUS status;

       length = offsetof(struct ctdb_rec_data, data) + key.dsize + data.dsize;

       rec = (struct ctdb_rec_data *)talloc_size(conn, length);
       NT_STATUS_HAVE_NO_MEMORY(rec);

       rec->length = length;
       rec->reqid  = db_id;
       rec->keylen = key.dsize;
       rec->datalen= data.dsize;
       memcpy(&rec->data[0], key.dptr, key.dsize);
       memcpy(&rec->data[key.dsize], data.dptr, data.dsize);

       recdata.dptr  = (uint8_t *)rec;
       recdata.dsize = length;

       status = ctdbd_control(conn, CTDB_CURRENT_NODE, 
                              CTDB_CONTROL_PERSISTENT_STORE, 
                              0, recdata, NULL, NULL, &cstatus);
       if (cstatus != 0) {
               return NT_STATUS_INTERNAL_DB_CORRUPTION;
       }
       return status;
}


#else

NTSTATUS ctdbd_init_connection(TALLOC_CTX *mem_ctx,
                         struct ctdbd_connection **pconn)
{
      return NT_STATUS_NOT_IMPLEMENTED;
}

#endif

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