source: vendor/current/source3/lib/messages_ctdbd.c

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

   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 "messages.h"
#include "util_tdb.h"
#include "lib/util/iov_buf.h"
#include "lib/messages_util.h"
#include "ctdbd_conn.h"
#include "lib/cluster_support.h"


struct messaging_ctdbd_context {
        struct ctdbd_connection *conn;
};

/*
 * This is a Samba3 hack/optimization. Routines like process_exists need to
 * talk to ctdbd, and they don't get handed a messaging context.
 */
static struct ctdbd_connection *global_ctdbd_connection;
static int global_ctdb_connection_pid;

struct ctdbd_connection *messaging_ctdbd_connection(void)
{
        if (!lp_clustering()) {
                return NULL;
        }

        if (global_ctdb_connection_pid == 0 &&
            global_ctdbd_connection == NULL) {
                struct tevent_context *ev;
                struct messaging_context *msg;

                ev = samba_tevent_context_init(NULL);
                if (!ev) {
                        DEBUG(0,("samba_tevent_context_init failed\n"));
                        return NULL;
                }

                msg = messaging_init(NULL, ev);
                if (!msg) {
                        DEBUG(0,("messaging_init failed\n"));
                        return NULL;
                }
        }

        if (global_ctdb_connection_pid != getpid()) {
                DEBUG(0,("messaging_ctdbd_connection():"
                         "valid for pid[%jd] but it's [%jd]\n",
                         (intmax_t)global_ctdb_connection_pid,
                         (intmax_t)getpid()));
                smb_panic("messaging_ctdbd_connection() invalid process\n");
        }

        return global_ctdbd_connection;
}

static int messaging_ctdb_send(struct server_id src,
                               struct server_id pid, int msg_type,
                               const struct iovec *iov, int iovlen,
                               const int *fds, size_t num_fds,
                               struct messaging_backend *backend)
{
        struct messaging_ctdbd_context *ctx = talloc_get_type_abort(
                backend->private_data, struct messaging_ctdbd_context);
        uint8_t hdr[MESSAGE_HDR_LENGTH];
        struct iovec iov2[iovlen+1];

        if (num_fds > 0) {
                return ENOSYS;
        }

        message_hdr_put(hdr, msg_type, src, pid);
        iov2[0] = (struct iovec){ .iov_base = hdr, .iov_len = sizeof(hdr) };
        memcpy(&iov2[1], iov, iovlen * sizeof(*iov));

        return ctdbd_messaging_send_iov(ctx->conn, pid.vnn, pid.pid,
                                        iov2, iovlen+1);
}

static int messaging_ctdbd_destructor(struct messaging_ctdbd_context *ctx)
{
        /*
         * The global connection just went away
         */
        global_ctdb_connection_pid = 0;
        global_ctdbd_connection = NULL;
        return 0;
}

static int messaging_ctdb_recv(
        uint32_t src_vnn, uint32_t dst_vnn, uint64_t dst_srvid,
        const uint8_t *msg, size_t msg_len, void *private_data)
{
        struct messaging_context *msg_ctx = talloc_get_type_abort(
                private_data, struct messaging_context);
        struct server_id me = messaging_server_id(msg_ctx);
        int ret;
        struct iovec iov;
        struct server_id src, dst;
        enum messaging_type msg_type;
        struct server_id_buf idbuf;

        if (msg_len < MESSAGE_HDR_LENGTH) {
                DEBUG(1, ("%s: message too short: %u\n", __func__,
                          (unsigned)msg_len));
                return 0;
        }

        message_hdr_get(&msg_type, &src, &dst, msg);

        iov = (struct iovec) {
                .iov_base = discard_const_p(uint8_t, msg) + MESSAGE_HDR_LENGTH,
                .iov_len = msg_len - MESSAGE_HDR_LENGTH
        };

        DEBUG(10, ("%s: Received message 0x%x len %u from %s\n",
                   __func__, (unsigned)msg_type, (unsigned)msg_len,
                   server_id_str_buf(src, &idbuf)));

        if (!server_id_same_process(&me, &dst)) {
                struct server_id_buf id1, id2;

                DEBUG(10, ("%s: I'm %s, ignoring msg to %s\n", __func__,
                           server_id_str_buf(me, &id1),
                           server_id_str_buf(dst, &id2)));
                return 0;
        }

        /*
         * Go through the event loop
         */

        ret = messaging_send_iov_from(msg_ctx, src, dst, msg_type,
                                      &iov, 1, NULL, 0);

        if (ret != 0) {
                DEBUG(10, ("%s: messaging_send_iov_from failed: %s\n",
                           __func__, strerror(ret)));
        }

        return 0;
}

int messaging_ctdbd_init(struct messaging_context *msg_ctx,
                         TALLOC_CTX *mem_ctx,
                         struct messaging_backend **presult)
{
        struct messaging_backend *result;
        struct messaging_ctdbd_context *ctx;
        int ret;

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

        if (!(ctx = talloc(result, struct messaging_ctdbd_context))) {
                DEBUG(0, ("talloc failed\n"));
                TALLOC_FREE(result);
                return ENOMEM;
        }

        ret = ctdbd_messaging_connection(ctx, lp_ctdbd_socket(),
                                         lp_ctdb_timeout(), &ctx->conn);

        if (ret != 0) {
                DEBUG(10, ("ctdbd_messaging_connection failed: %s\n",
                           strerror(ret)));
                TALLOC_FREE(result);
                return ret;
        }

        ret = ctdbd_register_msg_ctx(ctx->conn, msg_ctx,
                                     messaging_tevent_context(msg_ctx));

        if (ret != 0) {
                DEBUG(10, ("ctdbd_register_msg_ctx failed: %s\n",
                           strerror(ret)));
                TALLOC_FREE(result);
                return ret;
        }

        ret = register_with_ctdbd(ctx->conn, getpid(),
                                  messaging_ctdb_recv, msg_ctx);
        if (ret != 0) {
                DEBUG(10, ("register_with_ctdbd failed: %s\n",
                           strerror(ret)));
                TALLOC_FREE(result);
                return ret;
        }

        global_ctdb_connection_pid = getpid();
        global_ctdbd_connection = ctx->conn;
        talloc_set_destructor(ctx, messaging_ctdbd_destructor);

        set_my_vnn(ctdbd_vnn(ctx->conn));

        result->send_fn = messaging_ctdb_send;
        result->private_data = (void *)ctx;

        *presult = result;
        return 0;
}