client.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: client.c,v 12.2 2005/07/21 18:21:29 bostic Exp $
 */

#include "db_config.h"

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#ifdef HAVE_VXWORKS
#include <rpcLib.h>
#endif
#include <rpc/rpc.h>

#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#endif

#include "db_server.h"

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/db_am.h"
#include "dbinc/txn.h"
#include "dbinc_auto/rpc_client_ext.h"

static int __dbcl_c_destroy __P((DBC *));
static int __dbcl_txn_close __P((DB_ENV *));

/*
 * __dbcl_env_set_rpc_server --
 *      Initialize an environment's server.
 *
 * PUBLIC: int __dbcl_env_set_rpc_server
 * PUBLIC:     __P((DB_ENV *, void *, const char *, long, long, u_int32_t));
 */
int
__dbcl_env_set_rpc_server(dbenv, clnt, host, tsec, ssec, flags)
        DB_ENV *dbenv;
        void *clnt;
        const char *host;
        long tsec, ssec;
        u_int32_t flags;
{
        CLIENT *cl;
        struct timeval tp;

        COMPQUIET(flags, 0);

#ifdef HAVE_VXWORKS
        if (rpcTaskInit() != 0) {
                __db_err(dbenv, "Could not initialize VxWorks RPC");
                return (ERROR);
        }
#endif
        if (RPC_ON(dbenv)) {
                __db_err(dbenv, "Already set an RPC handle");
                return (EINVAL);
        }
        /*
         * Only create the client and set its timeout if the user
         * did not pass us a client structure to begin with.
         */
        if (clnt == NULL) {
                if ((cl = clnt_create((char *)host, DB_RPC_SERVERPROG,
                    DB_RPC_SERVERVERS, "tcp")) == NULL) {
                        __db_err(dbenv, clnt_spcreateerror((char *)host));
                        return (DB_NOSERVER);
                }
                if (tsec != 0) {
                        tp.tv_sec = tsec;
                        tp.tv_usec = 0;
                        (void)clnt_control(cl, CLSET_TIMEOUT, (char *)&tp);
                }
        } else {
                cl = (CLIENT *)clnt;
                F_SET(dbenv, DB_ENV_RPCCLIENT_GIVEN);
        }
        dbenv->cl_handle = cl;

        return (__dbcl_env_create(dbenv, ssec));
}

/*
 * __dbcl_env_close_wrap --
 *      Wrapper function for DB_ENV->close function for clients.
 *      We need a wrapper function to deal with the case where we
 *      either don't call dbenv->open or close gets an error.
 *      We need to release the handle no matter what.
 *
 * PUBLIC: int __dbcl_env_close_wrap __P((DB_ENV *, u_int32_t));
 */
int
__dbcl_env_close_wrap(dbenv, flags)
        DB_ENV * dbenv;
        u_int32_t flags;
{
        int ret, t_ret;

        ret = __dbcl_env_close(dbenv, flags);
        t_ret = __dbcl_refresh(dbenv);
        if (ret == 0 && t_ret != 0)
                ret = t_ret;
        return (ret);
}

/*
 * __dbcl_env_open_wrap --
 *      Wrapper function for DB_ENV->open function for clients.
 *      We need a wrapper function to deal with DB_USE_ENVIRON* flags
 *      and we don't want to complicate the generated code for env_open.
 *
 * PUBLIC: int __dbcl_env_open_wrap
 * PUBLIC:     __P((DB_ENV *, const char *, u_int32_t, int));
 */
int
__dbcl_env_open_wrap(dbenv, home, flags, mode)
        DB_ENV * dbenv;
        const char * home;
        u_int32_t flags;
        int mode;
{
        int ret;

        if (LF_ISSET(DB_THREAD)) {
                __db_err(dbenv, "DB_THREAD not allowed on RPC clients");
                return (EINVAL);
        }
        if ((ret = __db_home(dbenv, home, flags)) != 0)
                return (ret);
        return (__dbcl_env_open(dbenv, dbenv->db_home, flags, mode));
}

/*
 * __dbcl_db_open_wrap --
 *      Wrapper function for DB->open function for clients.
 *      We need a wrapper function to error on DB_THREAD flag.
 *      and we don't want to complicate the generated code.
 *
 * PUBLIC: int __dbcl_db_open_wrap
 * PUBLIC:     __P((DB *, DB_TXN *, const char *, const char *,
 * PUBLIC:     DBTYPE, u_int32_t, int));
 */
int
__dbcl_db_open_wrap(dbp, txnp, name, subdb, type, flags, mode)
        DB * dbp;
        DB_TXN * txnp;
        const char * name;
        const char * subdb;
        DBTYPE type;
        u_int32_t flags;
        int mode;
{
        return (__dbcl_db_open(dbp, txnp, name, subdb, type, flags, mode));
}

/*
 * __dbcl_refresh --
 *      Clean up an environment.
 *
 * PUBLIC: int __dbcl_refresh __P((DB_ENV *));
 */
int
__dbcl_refresh(dbenv)
        DB_ENV *dbenv;
{
        CLIENT *cl;
        int ret;

        cl = (CLIENT *)dbenv->cl_handle;

        ret = 0;
        if (dbenv->tx_handle != NULL) {
                /*
                 * We only need to free up our stuff, the caller
                 * of this function will call the server who will
                 * do all the real work.
                 */
                ret = __dbcl_txn_close(dbenv);
                dbenv->tx_handle = NULL;
        }
        if (!F_ISSET(dbenv, DB_ENV_RPCCLIENT_GIVEN) && cl != NULL)
                clnt_destroy(cl);
        dbenv->cl_handle = NULL;
        if (dbenv->db_home != NULL) {
                __os_free(dbenv, dbenv->db_home);
                dbenv->db_home = NULL;
        }
        return (ret);
}

/*
 * __dbcl_retcopy --
 *      Copy the returned data into the user's DBT, handling allocation flags,
 *      but not DB_DBT_PARTIAL.
 *
 * PUBLIC: int __dbcl_retcopy __P((DB_ENV *, DBT *,
 * PUBLIC:    void *, u_int32_t, void **, u_int32_t *));
 */
int
__dbcl_retcopy(dbenv, dbt, data, len, memp, memsize)
        DB_ENV *dbenv;
        DBT *dbt;
        void *data;
        u_int32_t len;
        void **memp;
        u_int32_t *memsize;
{
        int ret;
        u_int32_t orig_flags;

        /*
         * The RPC server handles DB_DBT_PARTIAL, so we mask it out here to
         * avoid the handling of partials in __db_retcopy.  Check first whether
         * the data has actually changed, so we don't try to copy over
         * read-only keys, which the RPC server always returns regardless.
         */
        orig_flags = dbt->flags;
        F_CLR(dbt, DB_DBT_PARTIAL);
        if (dbt->data != NULL && dbt->size == len &&
            memcmp(dbt->data, data, len) == 0)
                ret = 0;
        else
                ret = __db_retcopy(dbenv, dbt, data, len, memp, memsize);
        dbt->flags = orig_flags;
        return (ret);
}

/*
 * __dbcl_txn_close --
 *      Clean up an environment's transactions.
 */
static int
__dbcl_txn_close(dbenv)
        DB_ENV *dbenv;
{
        DB_TXN *txnp;
        DB_TXNMGR *tmgrp;
        int ret;

        ret = 0;
        tmgrp = dbenv->tx_handle;

        /*
         * This function can only be called once per process (i.e., not
         * once per thread), so no synchronization is required.
         * Also this function is called *after* the server has been called,
         * so the server has already closed/aborted any transactions that
         * were open on its side.  We only need to do local cleanup.
         */
        while ((txnp = TAILQ_FIRST(&tmgrp->txn_chain)) != NULL)
                __dbcl_txn_end(txnp);

        __os_free(dbenv, tmgrp);
        return (ret);

}

/*
 * __dbcl_txn_end --
 *      Clean up an transaction.
 * RECURSIVE FUNCTION:  Clean up nested transactions.
 *
 * PUBLIC: void __dbcl_txn_end __P((DB_TXN *));
 */
void
__dbcl_txn_end(txnp)
        DB_TXN *txnp;
{
        DB_ENV *dbenv;
        DB_TXN *kids;
        DB_TXNMGR *mgr;

        mgr = txnp->mgrp;
        dbenv = mgr->dbenv;

        /*
         * First take care of any kids we have
         */
        for (kids = TAILQ_FIRST(&txnp->kids);
            kids != NULL;
            kids = TAILQ_FIRST(&txnp->kids))
                __dbcl_txn_end(kids);

        /*
         * We are ending this transaction no matter what the parent
         * may eventually do, if we have a parent.  All those details
         * are taken care of by the server.  We only need to make sure
         * that we properly release resources.
         */
        if (txnp->parent != NULL)
                TAILQ_REMOVE(&txnp->parent->kids, txnp, klinks);
        TAILQ_REMOVE(&mgr->txn_chain, txnp, links);
        __os_free(dbenv, txnp);
}

/*
 * __dbcl_txn_setup --
 *      Setup a client transaction structure.
 *
 * PUBLIC: void __dbcl_txn_setup __P((DB_ENV *, DB_TXN *, DB_TXN *, u_int32_t));
 */
void
__dbcl_txn_setup(dbenv, txn, parent, id)
        DB_ENV *dbenv;
        DB_TXN *txn;
        DB_TXN *parent;
        u_int32_t id;
{
        txn->mgrp = dbenv->tx_handle;
        txn->parent = parent;
        txn->txnid = id;

        /*
         * XXX
         * In DB library the txn_chain is protected by the mgrp->mutexp.
         * However, that mutex is implemented in the environments shared
         * memory region.  The client library does not support all of the
         * region - that just get forwarded to the server.  Therefore,
         * the chain is unprotected here, but properly protected on the
         * server.
         */
        TAILQ_INSERT_TAIL(&txn->mgrp->txn_chain, txn, links);

        TAILQ_INIT(&txn->kids);

        if (parent != NULL)
                TAILQ_INSERT_HEAD(&parent->kids, txn, klinks);

        __dbcl_txn_init(txn);

        txn->flags = TXN_MALLOC;
}

/*
 * __dbcl_c_destroy --
 *      Destroy a cursor.
 */
static int
__dbcl_c_destroy(dbc)
        DBC *dbc;
{
        DB *dbp;

        dbp = dbc->dbp;

        TAILQ_REMOVE(&dbp->free_queue, dbc, links);
        /* Discard any memory used to store returned data. */
        if (dbc->my_rskey.data != NULL)
                __os_free(dbc->dbp->dbenv, dbc->my_rskey.data);
        if (dbc->my_rkey.data != NULL)
                __os_free(dbc->dbp->dbenv, dbc->my_rkey.data);
        if (dbc->my_rdata.data != NULL)
                __os_free(dbc->dbp->dbenv, dbc->my_rdata.data);
        __os_free(NULL, dbc);

        return (0);
}

/*
 * __dbcl_c_refresh --
 *      Refresh a cursor.  Move it from the active queue to the free queue.
 *
 * PUBLIC: void __dbcl_c_refresh __P((DBC *));
 */
void
__dbcl_c_refresh(dbc)
        DBC *dbc;
{
        DB *dbp;

        dbp = dbc->dbp;
        dbc->flags = 0;
        dbc->cl_id = 0;

        /*
         * If dbp->cursor fails locally, we use a local dbc so that
         * we can close it.  In that case, dbp will be NULL.
         */
        if (dbp != NULL) {
                TAILQ_REMOVE(&dbp->active_queue, dbc, links);
                TAILQ_INSERT_TAIL(&dbp->free_queue, dbc, links);
        }
}

/*
 * __dbcl_c_setup --
 *      Allocate a cursor.
 *
 * PUBLIC: int __dbcl_c_setup __P((u_int, DB *, DBC **));
 */
int
__dbcl_c_setup(cl_id, dbp, dbcp)
        u_int cl_id;
        DB *dbp;
        DBC **dbcp;
{
        DBC *dbc, tmpdbc;
        int ret;

        if ((dbc = TAILQ_FIRST(&dbp->free_queue)) != NULL)
                TAILQ_REMOVE(&dbp->free_queue, dbc, links);
        else {
                if ((ret =
                    __os_calloc(dbp->dbenv, 1, sizeof(DBC), &dbc)) != 0) {
                        /*
                         * If we die here, set up a tmp dbc to call the
                         * server to shut down that cursor.
                         */
                        tmpdbc.dbp = NULL;
                        tmpdbc.cl_id = cl_id;
                        (void)__dbcl_dbc_c_close(&tmpdbc);
                        return (ret);
                }

                __dbcl_dbc_init(dbc);

                /*
                 * !!!
                 * Set up the local destroy function -- we're not really
                 * an access method, but it does what we need.
                 */
                dbc->c_am_destroy = __dbcl_c_destroy;
        }
        dbc->cl_id = cl_id;
        dbc->dbp = dbp;
        TAILQ_INSERT_TAIL(&dbp->active_queue, dbc, links);
        *dbcp = dbc;
        return (0);
}

/*
 * __dbcl_dbclose_common --
 *      Common code for closing/cleaning a dbp.
 *
 * PUBLIC: int __dbcl_dbclose_common __P((DB *));
 */
int
__dbcl_dbclose_common(dbp)
        DB *dbp;
{
        int ret, t_ret;
        DBC *dbc;

        /*
         * Go through the active cursors and call the cursor recycle routine,
         * which resolves pending operations and moves the cursors onto the
         * free list.  Then, walk the free list and call the cursor destroy
         * routine.
         *
         * NOTE:  We do not need to use the join_queue for join cursors.
         * See comment in __dbcl_dbjoin_ret.
         */
        ret = 0;
        while ((dbc = TAILQ_FIRST(&dbp->active_queue)) != NULL)
                __dbcl_c_refresh(dbc);
        while ((dbc = TAILQ_FIRST(&dbp->free_queue)) != NULL)
                if ((t_ret = __dbcl_c_destroy(dbc)) != 0 && ret == 0)
                        ret = t_ret;

        TAILQ_INIT(&dbp->free_queue);
        TAILQ_INIT(&dbp->active_queue);
        /* Discard any memory used to store returned data. */
        if (dbp->my_rskey.data != NULL)
                __os_free(dbp->dbenv, dbp->my_rskey.data);
        if (dbp->my_rkey.data != NULL)
                __os_free(dbp->dbenv, dbp->my_rkey.data);
        if (dbp->my_rdata.data != NULL)
                __os_free(dbp->dbenv, dbp->my_rdata.data);

        memset(dbp, CLEAR_BYTE, sizeof(*dbp));
        __os_free(NULL, dbp);
        return (ret);
}

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