source: branches/samba-3.5.x/lib/util/util_tdb.c

/* 
   Unix SMB/CIFS implementation.

   tdb utility functions

   Copyright (C) Andrew Tridgell 1992-2006
   
   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 "../lib/util/util_tdb.h"

/* these are little tdb utility functions that are meant to make
   dealing with a tdb database a little less cumbersome in Samba */

/***************************************************************
 Make a TDB_DATA and keep the const warning in one place
****************************************************************/

TDB_DATA make_tdb_data(const uint8_t *dptr, size_t dsize)
{
        TDB_DATA ret;
        ret.dptr = discard_const_p(uint8_t, dptr);
        ret.dsize = dsize;
        return ret;
}

bool tdb_data_equal(TDB_DATA t1, TDB_DATA t2)
{
        if (t1.dsize != t2.dsize) {
                return false;
        }
        return (memcmp(t1.dptr, t2.dptr, t1.dsize) == 0);
}

TDB_DATA string_tdb_data(const char *string)
{
        return make_tdb_data((const uint8_t *)string, string ? strlen(string) : 0 );
}

TDB_DATA string_term_tdb_data(const char *string)
{
        return make_tdb_data((const uint8_t *)string, string ? strlen(string) + 1 : 0);
}

/****************************************************************************
 Lock a chain by string. Return -1 if lock failed.
****************************************************************************/

int tdb_lock_bystring(struct tdb_context *tdb, const char *keyval)
{
        TDB_DATA key = string_term_tdb_data(keyval);
        
        return tdb_chainlock(tdb, key);
}

/****************************************************************************
 Unlock a chain by string.
****************************************************************************/

void tdb_unlock_bystring(struct tdb_context *tdb, const char *keyval)
{
        TDB_DATA key = string_term_tdb_data(keyval);

        tdb_chainunlock(tdb, key);
}

/****************************************************************************
 Read lock a chain by string. Return -1 if lock failed.
****************************************************************************/

int tdb_read_lock_bystring(struct tdb_context *tdb, const char *keyval)
{
        TDB_DATA key = string_term_tdb_data(keyval);
        
        return tdb_chainlock_read(tdb, key);
}

/****************************************************************************
 Read unlock a chain by string.
****************************************************************************/

void tdb_read_unlock_bystring(struct tdb_context *tdb, const char *keyval)
{
        TDB_DATA key = string_term_tdb_data(keyval);
        
        tdb_chainunlock_read(tdb, key);
}


/****************************************************************************
 Fetch a int32_t value by a arbitrary blob key, return -1 if not found.
 Output is int32_t in native byte order.
****************************************************************************/

int32_t tdb_fetch_int32_byblob(struct tdb_context *tdb, TDB_DATA key)
{
        TDB_DATA data;
        int32_t ret;

        data = tdb_fetch(tdb, key);
        if (!data.dptr || data.dsize != sizeof(int32_t)) {
                SAFE_FREE(data.dptr);
                return -1;
        }

        ret = IVAL(data.dptr,0);
        SAFE_FREE(data.dptr);
        return ret;
}

/****************************************************************************
 Fetch a int32_t value by string key, return -1 if not found.
 Output is int32_t in native byte order.
****************************************************************************/

int32_t tdb_fetch_int32(struct tdb_context *tdb, const char *keystr)
{
        return tdb_fetch_int32_byblob(tdb, string_term_tdb_data(keystr));
}

/****************************************************************************
 Store a int32_t value by an arbitary blob key, return 0 on success, -1 on failure.
 Input is int32_t in native byte order. Output in tdb is in little-endian.
****************************************************************************/

int tdb_store_int32_byblob(struct tdb_context *tdb, TDB_DATA key, int32_t v)
{
        TDB_DATA data;
        int32_t v_store;

        SIVAL(&v_store,0,v);
        data.dptr = (unsigned char *)&v_store;
        data.dsize = sizeof(int32_t);

        return tdb_store(tdb, key, data, TDB_REPLACE);
}

/****************************************************************************
 Store a int32_t value by string key, return 0 on success, -1 on failure.
 Input is int32_t in native byte order. Output in tdb is in little-endian.
****************************************************************************/

int tdb_store_int32(struct tdb_context *tdb, const char *keystr, int32_t v)
{
        return tdb_store_int32_byblob(tdb, string_term_tdb_data(keystr), v);
}

/****************************************************************************
 Fetch a uint32_t value by a arbitrary blob key, return false if not found.
 Output is uint32_t in native byte order.
****************************************************************************/

bool tdb_fetch_uint32_byblob(struct tdb_context *tdb, TDB_DATA key, uint32_t *value)
{
        TDB_DATA data;

        data = tdb_fetch(tdb, key);
        if (!data.dptr || data.dsize != sizeof(uint32_t)) {
                SAFE_FREE(data.dptr);
                return false;
        }

        *value = IVAL(data.dptr,0);
        SAFE_FREE(data.dptr);
        return true;
}

/****************************************************************************
 Fetch a uint32_t value by string key, return false if not found.
 Output is uint32_t in native byte order.
****************************************************************************/

bool tdb_fetch_uint32(struct tdb_context *tdb, const char *keystr, uint32_t *value)
{
        return tdb_fetch_uint32_byblob(tdb, string_term_tdb_data(keystr), value);
}

/****************************************************************************
 Store a uint32_t value by an arbitary blob key, return 0 on success, -1 on failure.
 Input is uint32_t in native byte order. Output in tdb is in little-endian.
****************************************************************************/

bool tdb_store_uint32_byblob(struct tdb_context *tdb, TDB_DATA key, uint32_t value)
{
        TDB_DATA data;
        uint32_t v_store;
        bool ret = true;

        SIVAL(&v_store, 0, value);
        data.dptr = (unsigned char *)&v_store;
        data.dsize = sizeof(uint32_t);

        if (tdb_store(tdb, key, data, TDB_REPLACE) == -1)
                ret = false;

        return ret;
}

/****************************************************************************
 Store a uint32_t value by string key, return 0 on success, -1 on failure.
 Input is uint32_t in native byte order. Output in tdb is in little-endian.
****************************************************************************/

bool tdb_store_uint32(struct tdb_context *tdb, const char *keystr, uint32_t value)
{
        return tdb_store_uint32_byblob(tdb, string_term_tdb_data(keystr), value);
}
/****************************************************************************
 Store a buffer by a null terminated string key.  Return 0 on success, -1
 on failure.
****************************************************************************/

int tdb_store_bystring(struct tdb_context *tdb, const char *keystr, TDB_DATA data, int flags)
{
        TDB_DATA key = string_term_tdb_data(keystr);
        
        return tdb_store(tdb, key, data, flags);
}

/****************************************************************************
 Fetch a buffer using a null terminated string key.  Don't forget to call
 free() on the result dptr.
****************************************************************************/

TDB_DATA tdb_fetch_bystring(struct tdb_context *tdb, const char *keystr)
{
        TDB_DATA key = string_term_tdb_data(keystr);

        return tdb_fetch(tdb, key);
}

/****************************************************************************
 Delete an entry using a null terminated string key. 
****************************************************************************/

int tdb_delete_bystring(struct tdb_context *tdb, const char *keystr)
{
        TDB_DATA key = string_term_tdb_data(keystr);

        return tdb_delete(tdb, key);
}

/****************************************************************************
 Atomic integer change. Returns old value. To create, set initial value in *oldval. 
****************************************************************************/

int32_t tdb_change_int32_atomic(struct tdb_context *tdb, const char *keystr, int32_t *oldval, int32_t change_val)
{
        int32_t val;
        int32_t ret = -1;

        if (tdb_lock_bystring(tdb, keystr) == -1)
                return -1;

        if ((val = tdb_fetch_int32(tdb, keystr)) == -1) {
                /* The lookup failed */
                if (tdb_error(tdb) != TDB_ERR_NOEXIST) {
                        /* but not because it didn't exist */
                        goto err_out;
                }
                
                /* Start with 'old' value */
                val = *oldval;

        } else {
                /* It worked, set return value (oldval) to tdb data */
                *oldval = val;
        }

        /* Increment value for storage and return next time */
        val += change_val;
                
        if (tdb_store_int32(tdb, keystr, val) == -1)
                goto err_out;

        ret = 0;

  err_out:

        tdb_unlock_bystring(tdb, keystr);
        return ret;
}

/****************************************************************************
 Atomic unsigned integer change. Returns old value. To create, set initial value in *oldval. 
****************************************************************************/

bool tdb_change_uint32_atomic(struct tdb_context *tdb, const char *keystr, uint32_t *oldval, uint32_t change_val)
{
        uint32_t val;
        bool ret = false;

        if (tdb_lock_bystring(tdb, keystr) == -1)
                return false;

        if (!tdb_fetch_uint32(tdb, keystr, &val)) {
                /* It failed */
                if (tdb_error(tdb) != TDB_ERR_NOEXIST) { 
                        /* and not because it didn't exist */
                        goto err_out;
                }

                /* Start with 'old' value */
                val = *oldval;

        } else {
                /* it worked, set return value (oldval) to tdb data */
                *oldval = val;

        }

        /* get a new value to store */
        val += change_val;
                
        if (!tdb_store_uint32(tdb, keystr, val))
                goto err_out;

        ret = true;

  err_out:

        tdb_unlock_bystring(tdb, keystr);
        return ret;
}

/****************************************************************************
 Allow tdb_delete to be used as a tdb_traversal_fn.
****************************************************************************/

int tdb_traverse_delete_fn(struct tdb_context *the_tdb, TDB_DATA key, TDB_DATA dbuf,
                     void *state)
{
    return tdb_delete(the_tdb, key);
}