Zero out the out policy handler in lsa_Close

[Samba/gebeck_regimport.git] / source3 / lib / util_tdb.c

/* 
   Unix SMB/CIFS implementation.
   tdb utility functions
   Copyright (C) Andrew Tridgell   1992-1998
   Copyright (C) Rafal Szczesniak  2002
   
   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"
#undef malloc
#undef realloc
#undef calloc
#undef strdup

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

static SIG_ATOMIC_T gotalarm;

/***************************************************************
 Signal function to tell us we timed out.
****************************************************************/

static void gotalarm_sig(void)
{
        gotalarm = 1;
}

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

TDB_DATA make_tdb_data(const uint8 *dptr, size_t dsize)
{
        TDB_DATA ret;
        ret.dptr = CONST_DISCARD(uint8 *, dptr);
        ret.dsize = dsize;
        return ret;
}

TDB_DATA string_tdb_data(const char *string)
{
        return make_tdb_data((const uint8 *)string, string ? strlen(string) : 0 );
}

TDB_DATA string_term_tdb_data(const char *string)
{
        return make_tdb_data((const uint8 *)string, string ? strlen(string) + 1 : 0);
}

/****************************************************************************
 Lock a chain with timeout (in seconds).
****************************************************************************/

static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout, int rw_type)
{
        /* Allow tdb_chainlock to be interrupted by an alarm. */
        int ret;
        gotalarm = 0;

        if (timeout) {
                CatchSignal(SIGALRM, SIGNAL_CAST gotalarm_sig);
                tdb_setalarm_sigptr(tdb, &gotalarm);
                alarm(timeout);
        }

        if (rw_type == F_RDLCK)
                ret = tdb_chainlock_read(tdb, key);
        else
                ret = tdb_chainlock(tdb, key);

        if (timeout) {
                alarm(0);
                tdb_setalarm_sigptr(tdb, NULL);
                CatchSignal(SIGALRM, SIGNAL_CAST SIG_IGN);
                if (gotalarm) {
                        DEBUG(0,("tdb_chainlock_with_timeout_internal: alarm (%u) timed out for key %s in tdb %s\n",
                                timeout, key.dptr, tdb_name(tdb)));
                        /* TODO: If we time out waiting for a lock, it might
                         * be nice to use F_GETLK to get the pid of the
                         * process currently holding the lock and print that
                         * as part of the debugging message. -- mbp */
                        return -1;
                }
        }

        return ret;
}

/****************************************************************************
 Write lock a chain. Return -1 if timeout or lock failed.
****************************************************************************/

int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout)
{
        return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_WRLCK);
}

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

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

int tdb_lock_bystring_with_timeout(TDB_CONTEXT *tdb, const char *keyval,
                                   int timeout)
{
        TDB_DATA key = string_term_tdb_data(keyval);
        
        return tdb_chainlock_with_timeout(tdb, key, timeout);
}

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

void tdb_unlock_bystring(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 timeout or lock failed.
****************************************************************************/

int tdb_read_lock_bystring_with_timeout(TDB_CONTEXT *tdb, const char *keyval, unsigned int timeout)
{
        TDB_DATA key = string_term_tdb_data(keyval);
        
        return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_RDLCK);
}

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

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


/****************************************************************************
 Fetch a int32 value by a arbitrary blob key, return -1 if not found.
 Output is int32 in native byte order.
****************************************************************************/

int32 tdb_fetch_int32_byblob(TDB_CONTEXT *tdb, TDB_DATA key)
{
        TDB_DATA data;
        int32 ret;

        data = tdb_fetch(tdb, key);
        if (!data.dptr || data.dsize != sizeof(int32)) {
                SAFE_FREE(data.dptr);
                return -1;
        }

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

/****************************************************************************
 Fetch a int32 value by string key, return -1 if not found.
 Output is int32 in native byte order.
****************************************************************************/

int32 tdb_fetch_int32(TDB_CONTEXT *tdb, const char *keystr)
{
        TDB_DATA key = string_term_tdb_data(keystr);

        return tdb_fetch_int32_byblob(tdb, key);
}

/****************************************************************************
 Store a int32 value by an arbitary blob key, return 0 on success, -1 on failure.
 Input is int32 in native byte order. Output in tdb is in little-endian.
****************************************************************************/

int tdb_store_int32_byblob(TDB_CONTEXT *tdb, TDB_DATA key, int32 v)
{
        TDB_DATA data;
        int32 v_store;

        SIVAL(&v_store,0,v);
        data.dptr = (uint8 *)&v_store;
        data.dsize = sizeof(int32);

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

/****************************************************************************
 Store a int32 value by string key, return 0 on success, -1 on failure.
 Input is int32 in native byte order. Output in tdb is in little-endian.
****************************************************************************/

int tdb_store_int32(TDB_CONTEXT *tdb, const char *keystr, int32 v)
{
        TDB_DATA key = string_term_tdb_data(keystr);

        return tdb_store_int32_byblob(tdb, key, v);
}

/****************************************************************************
 Fetch a uint32 value by a arbitrary blob key, return -1 if not found.
 Output is uint32 in native byte order.
****************************************************************************/

bool tdb_fetch_uint32_byblob(TDB_CONTEXT *tdb, TDB_DATA key, uint32 *value)
{
        TDB_DATA data;

        data = tdb_fetch(tdb, key);
        if (!data.dptr || data.dsize != sizeof(uint32)) {
                SAFE_FREE(data.dptr);
                return False;
        }

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

/****************************************************************************
 Fetch a uint32 value by string key, return -1 if not found.
 Output is uint32 in native byte order.
****************************************************************************/

bool tdb_fetch_uint32(TDB_CONTEXT *tdb, const char *keystr, uint32 *value)
{
        TDB_DATA key = string_term_tdb_data(keystr);

        return tdb_fetch_uint32_byblob(tdb, key, value);
}

/****************************************************************************
 Store a uint32 value by an arbitary blob key, return 0 on success, -1 on failure.
 Input is uint32 in native byte order. Output in tdb is in little-endian.
****************************************************************************/

bool tdb_store_uint32_byblob(TDB_CONTEXT *tdb, TDB_DATA key, uint32 value)
{
        TDB_DATA data;
        uint32 v_store;
        bool ret = True;

        SIVAL(&v_store, 0, value);
        data.dptr = (uint8 *)&v_store;
        data.dsize = sizeof(uint32);

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

        return ret;
}

/****************************************************************************
 Store a uint32 value by string key, return 0 on success, -1 on failure.
 Input is uint32 in native byte order. Output in tdb is in little-endian.
****************************************************************************/

bool tdb_store_uint32(TDB_CONTEXT *tdb, const char *keystr, uint32 value)
{
        TDB_DATA key = string_term_tdb_data(keystr);

        return tdb_store_uint32_byblob(tdb, key, value);
}
/****************************************************************************
 Store a buffer by a null terminated string key.  Return 0 on success, -1
 on failure.
****************************************************************************/

int tdb_store_bystring(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);
}

int tdb_trans_store_bystring(TDB_CONTEXT *tdb, const char *keystr,
                             TDB_DATA data, int flags)
{
        TDB_DATA key = string_term_tdb_data(keystr);
        
        return tdb_trans_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(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(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 tdb_change_int32_atomic(TDB_CONTEXT *tdb, const char *keystr, int32 *oldval, int32 change_val)
{
        int32 val;
        int32 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(TDB_CONTEXT *tdb, const char *keystr, uint32 *oldval, uint32 change_val)
{
        uint32 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;
}

/****************************************************************************
 Useful pair of routines for packing/unpacking data consisting of
 integers and strings.
****************************************************************************/

size_t tdb_pack_va(uint8 *buf, int bufsize, const char *fmt, va_list ap)
{
        uint8 bt;
        uint16 w;
        uint32 d;
        int i;
        void *p;
        int len;
        char *s;
        char c;
        uint8 *buf0 = buf;
        const char *fmt0 = fmt;
        int bufsize0 = bufsize;

        while (*fmt) {
                switch ((c = *fmt++)) {
                case 'b': /* unsigned 8-bit integer */
                        len = 1;
                        bt = (uint8)va_arg(ap, int);
                        if (bufsize && bufsize >= len)
                                SSVAL(buf, 0, bt);
                        break;
                case 'w': /* unsigned 16-bit integer */
                        len = 2;
                        w = (uint16)va_arg(ap, int);
                        if (bufsize && bufsize >= len)
                                SSVAL(buf, 0, w);
                        break;
                case 'd': /* signed 32-bit integer (standard int in most systems) */
                        len = 4;
                        d = va_arg(ap, uint32);
                        if (bufsize && bufsize >= len)
                                SIVAL(buf, 0, d);
                        break;
                case 'p': /* pointer */
                        len = 4;
                        p = va_arg(ap, void *);
                        d = p?1:0;
                        if (bufsize && bufsize >= len)
                                SIVAL(buf, 0, d);
                        break;
                case 'P': /* null-terminated string */
                        s = va_arg(ap,char *);
                        w = strlen(s);
                        len = w + 1;
                        if (bufsize && bufsize >= len)
                                memcpy(buf, s, len);
                        break;
                case 'f': /* null-terminated string */
                        s = va_arg(ap,char *);
                        w = strlen(s);
                        len = w + 1;
                        if (bufsize && bufsize >= len)
                                memcpy(buf, s, len);
                        break;
                case 'B': /* fixed-length string */
                        i = va_arg(ap, int);
                        s = va_arg(ap, char *);
                        len = 4+i;
                        if (bufsize && bufsize >= len) {
                                SIVAL(buf, 0, i);
                                memcpy(buf+4, s, i);
                        }
                        break;
                default:
                        DEBUG(0,("Unknown tdb_pack format %c in %s\n", 
                                 c, fmt));
                        len = 0;
                        break;
                }

                buf += len;
                if (bufsize)
                        bufsize -= len;
                if (bufsize < 0)
                        bufsize = 0;
        }

        DEBUG(18,("tdb_pack_va(%s, %d) -> %d\n", 
                 fmt0, bufsize0, (int)PTR_DIFF(buf, buf0)));
        
        return PTR_DIFF(buf, buf0);
}

size_t tdb_pack(uint8 *buf, int bufsize, const char *fmt, ...)
{
        va_list ap;
        size_t result;

        va_start(ap, fmt);
        result = tdb_pack_va(buf, bufsize, fmt, ap);
        va_end(ap);
        return result;
}

bool tdb_pack_append(TALLOC_CTX *mem_ctx, uint8 **buf, size_t *len,
                     const char *fmt, ...)
{
        va_list ap;
        size_t len1, len2;

        va_start(ap, fmt);
        len1 = tdb_pack_va(NULL, 0, fmt, ap);
        va_end(ap);

        if (mem_ctx != NULL) {
                *buf = TALLOC_REALLOC_ARRAY(mem_ctx, *buf, uint8,
                                            (*len) + len1);
        } else {
                *buf = SMB_REALLOC_ARRAY(*buf, uint8, (*len) + len1);
        }

        if (*buf == NULL) {
                return False;
        }

        va_start(ap, fmt);
        len2 = tdb_pack_va((*buf)+(*len), len1, fmt, ap);
        va_end(ap);

        if (len1 != len2) {
                return False;
        }

        *len += len2;

        return True;
}

/****************************************************************************
 Useful pair of routines for packing/unpacking data consisting of
 integers and strings.
****************************************************************************/

int tdb_unpack(const uint8 *buf, int bufsize, const char *fmt, ...)
{
        va_list ap;
        uint8 *bt;
        uint16 *w;
        uint32 *d;
        int len;
        int *i;
        void **p;
        char *s, **b, **ps;
        char c;
        const uint8 *buf0 = buf;
        const char *fmt0 = fmt;
        int bufsize0 = bufsize;

        va_start(ap, fmt);

        while (*fmt) {
                switch ((c=*fmt++)) {
                case 'b':
                        len = 1;
                        bt = va_arg(ap, uint8 *);
                        if (bufsize < len)
                                goto no_space;
                        *bt = SVAL(buf, 0);
                        break;
                case 'w':
                        len = 2;
                        w = va_arg(ap, uint16 *);
                        if (bufsize < len)
                                goto no_space;
                        *w = SVAL(buf, 0);
                        break;
                case 'd':
                        len = 4;
                        d = va_arg(ap, uint32 *);
                        if (bufsize < len)
                                goto no_space;
                        *d = IVAL(buf, 0);
                        break;
                case 'p':
                        len = 4;
                        p = va_arg(ap, void **);
                        if (bufsize < len)
                                goto no_space;
                        /*
                         * This isn't a real pointer - only a token (1 or 0)
                         * to mark the fact a pointer is present.
                         */

                        *p = (void *)(IVAL(buf, 0) ? (void *)1 : NULL);
                        break;
                case 'P':
                        /* Return malloc'ed string. */
                        ps = va_arg(ap,char **);
                        len = strlen((const char *)buf) + 1;
                        *ps = SMB_STRDUP((const char *)buf);
                        break;
                case 'f':
                        s = va_arg(ap,char *);
                        len = strlen((const char *)buf) + 1;
                        if (bufsize < len || len > sizeof(fstring))
                                goto no_space;
                        memcpy(s, buf, len);
                        break;
                case 'B':
                        i = va_arg(ap, int *);
                        b = va_arg(ap, char **);
                        len = 4;
                        if (bufsize < len)
                                goto no_space;
                        *i = IVAL(buf, 0);
                        if (! *i) {
                                *b = NULL;
                                break;
                        }
                        len += *i;
                        if (bufsize < len)
                                goto no_space;
                        *b = (char *)SMB_MALLOC(*i);
                        if (! *b)
                                goto no_space;
                        memcpy(*b, buf+4, *i);
                        break;
                default:
                        DEBUG(0,("Unknown tdb_unpack format %c in %s\n",
                                 c, fmt));

                        len = 0;
                        break;
                }

                buf += len;
                bufsize -= len;
        }

        va_end(ap);

        DEBUG(18,("tdb_unpack(%s, %d) -> %d\n",
                 fmt0, bufsize0, (int)PTR_DIFF(buf, buf0)));

        return PTR_DIFF(buf, buf0);

 no_space:
        va_end(ap);
        return -1;
}


/****************************************************************************
 Log tdb messages via DEBUG().
****************************************************************************/

static void tdb_log(TDB_CONTEXT *tdb, enum tdb_debug_level level, const char *format, ...)
{
        va_list ap;
        char *ptr = NULL;
        int ret;

        va_start(ap, format);
        ret = vasprintf(&ptr, format, ap);
        va_end(ap);

        if ((ret == -1) || !*ptr)
                return;

        DEBUG((int)level, ("tdb(%s): %s", tdb_name(tdb) ? tdb_name(tdb) : "unnamed", ptr));
        SAFE_FREE(ptr);
}

/****************************************************************************
 Like tdb_open() but also setup a logging function that redirects to
 the samba DEBUG() system.
****************************************************************************/

TDB_CONTEXT *tdb_open_log(const char *name, int hash_size, int tdb_flags,
                          int open_flags, mode_t mode)
{
        TDB_CONTEXT *tdb;
        struct tdb_logging_context log_ctx;

        if (!lp_use_mmap())
                tdb_flags |= TDB_NOMMAP;

        log_ctx.log_fn = tdb_log;
        log_ctx.log_private = NULL;

        if ((hash_size == 0) && (name != NULL)) {
                const char *base = strrchr_m(name, '/');
                if (base != NULL) {
                        base += 1;
                }
                else {
                        base = name;
                }
                hash_size = lp_parm_int(-1, "tdb_hashsize", base, 0);
        }

        tdb = tdb_open_ex(name, hash_size, tdb_flags, 
                          open_flags, mode, &log_ctx, NULL);
        if (!tdb)
                return NULL;

        return tdb;
}

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

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



/**
 * Search across the whole tdb for keys that match the given pattern
 * return the result as a list of keys
 *
 * @param tdb pointer to opened tdb file context
 * @param pattern searching pattern used by fnmatch(3) functions
 *
 * @return list of keys found by looking up with given pattern
 **/
TDB_LIST_NODE *tdb_search_keys(TDB_CONTEXT *tdb, const char* pattern)
{
        TDB_DATA key, next;
        TDB_LIST_NODE *list = NULL;
        TDB_LIST_NODE *rec = NULL;
        
        for (key = tdb_firstkey(tdb); key.dptr; key = next) {
                /* duplicate key string to ensure null-termination */
                char *key_str = SMB_STRNDUP((const char *)key.dptr, key.dsize);
                if (!key_str) {
                        DEBUG(0, ("tdb_search_keys: strndup() failed!\n"));
                        smb_panic("strndup failed!\n");
                }
                
                DEBUG(18, ("checking %s for match to pattern %s\n", key_str, pattern));
                
                next = tdb_nextkey(tdb, key);

                /* do the pattern checking */
                if (fnmatch(pattern, key_str, 0) == 0) {
                        rec = SMB_MALLOC_P(TDB_LIST_NODE);
                        ZERO_STRUCTP(rec);

                        rec->node_key = key;
        
                        DLIST_ADD_END(list, rec, TDB_LIST_NODE *);
                
                        DEBUG(18, ("checking %s matched pattern %s\n", key_str, pattern));
                } else {
                        free(key.dptr);
                }
                
                /* free duplicated key string */
                free(key_str);
        }
        
        return list;

}


/**
 * Free the list returned by tdb_search_keys
 *
 * @param node list of results found by tdb_search_keys
 **/
void tdb_search_list_free(TDB_LIST_NODE* node)
{
        TDB_LIST_NODE *next_node;
        
        while (node) {
                next_node = node->next;
                SAFE_FREE(node->node_key.dptr);
                SAFE_FREE(node);
                node = next_node;
        };
}

/****************************************************************************
 tdb_store, wrapped in a transaction. This way we make sure that a process
 that dies within writing does not leave a corrupt tdb behind.
****************************************************************************/

int tdb_trans_store(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf,
                    int flag)
{
        int res;

        if ((res = tdb_transaction_start(tdb)) != 0) {
                DEBUG(5, ("tdb_transaction_start failed\n"));
                return res;
        }

        if ((res = tdb_store(tdb, key, dbuf, flag)) != 0) {
                DEBUG(10, ("tdb_store failed\n"));
                if (tdb_transaction_cancel(tdb) != 0) {
                        smb_panic("Cancelling transaction failed");
                }
                return res;
        }

        if ((res = tdb_transaction_commit(tdb)) != 0) {
                DEBUG(5, ("tdb_transaction_commit failed\n"));
        }

        return res;
}

/****************************************************************************
 tdb_delete, wrapped in a transaction. This way we make sure that a process
 that dies within deleting does not leave a corrupt tdb behind.
****************************************************************************/

int tdb_trans_delete(struct tdb_context *tdb, TDB_DATA key)
{
        int res;

        if ((res = tdb_transaction_start(tdb)) != 0) {
                DEBUG(5, ("tdb_transaction_start failed\n"));
                return res;
        }

        if ((res = tdb_delete(tdb, key)) != 0) {
                DEBUG(10, ("tdb_delete failed\n"));
                if (tdb_transaction_cancel(tdb) != 0) {
                        smb_panic("Cancelling transaction failed");
                }
                return res;
        }

        if ((res = tdb_transaction_commit(tdb)) != 0) {
                DEBUG(5, ("tdb_transaction_commit failed\n"));
        }

        return res;
}

/*
 Log tdb messages via DEBUG().
*/
static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level, 
                         const char *format, ...) PRINTF_ATTRIBUTE(3,4);

static void tdb_wrap_log(TDB_CONTEXT *tdb, enum tdb_debug_level level, 
                         const char *format, ...)
{
        va_list ap;
        char *ptr = NULL;
        int debuglevel = 0;
        int ret;

        switch (level) {
        case TDB_DEBUG_FATAL:
                debug_level = 0;
                break;
        case TDB_DEBUG_ERROR:
                debuglevel = 1;
                break;
        case TDB_DEBUG_WARNING:
                debuglevel = 2;
                break;
        case TDB_DEBUG_TRACE:
                debuglevel = 5;
                break;
        default:
                debuglevel = 0;
        }               

        va_start(ap, format);
        ret = vasprintf(&ptr, format, ap);
        va_end(ap);

        if (ret != -1) {
                const char *name = tdb_name(tdb);
                DEBUG(debuglevel, ("tdb(%s): %s", name ? name : "unnamed", ptr));
                free(ptr);
        }
}

static struct tdb_wrap *tdb_list;

/* destroy the last connection to a tdb */
static int tdb_wrap_destructor(struct tdb_wrap *w)
{
        tdb_close(w->tdb);
        DLIST_REMOVE(tdb_list, w);
        return 0;
}                                

/*
  wrapped connection to a tdb database
  to close just talloc_free() the tdb_wrap pointer
 */
struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
                               const char *name, int hash_size, int tdb_flags,
                               int open_flags, mode_t mode)
{
        struct tdb_wrap *w;
        struct tdb_logging_context log_ctx;
        log_ctx.log_fn = tdb_wrap_log;

        if (!lp_use_mmap())
                tdb_flags |= TDB_NOMMAP;

        for (w=tdb_list;w;w=w->next) {
                if (strcmp(name, w->name) == 0) {
                        /*
                         * Yes, talloc_reference is exactly what we want
                         * here. Otherwise we would have to implement our own
                         * reference counting.
                         */
                        return talloc_reference(mem_ctx, w);
                }
        }

        w = talloc(mem_ctx, struct tdb_wrap);
        if (w == NULL) {
                return NULL;
        }

        if (!(w->name = talloc_strdup(w, name))) {
                talloc_free(w);
                return NULL;
        }

        if ((hash_size == 0) && (name != NULL)) {
                const char *base = strrchr_m(name, '/');
                if (base != NULL) {
                        base += 1;
                }
                else {
                        base = name;
                }
                hash_size = lp_parm_int(-1, "tdb_hashsize", base, 0);
        }

        w->tdb = tdb_open_ex(name, hash_size, tdb_flags, 
                             open_flags, mode, &log_ctx, NULL);
        if (w->tdb == NULL) {
                talloc_free(w);
                return NULL;
        }

        talloc_set_destructor(w, tdb_wrap_destructor);

        DLIST_ADD(tdb_list, w);

        return w;
}

NTSTATUS map_nt_error_from_tdb(enum TDB_ERROR err)
{
        struct { enum TDB_ERROR err; NTSTATUS status; } map[] =
                { { TDB_SUCCESS,        NT_STATUS_OK },
                  { TDB_ERR_CORRUPT,    NT_STATUS_INTERNAL_DB_CORRUPTION },
                  { TDB_ERR_IO,         NT_STATUS_UNEXPECTED_IO_ERROR },
                  { TDB_ERR_OOM,        NT_STATUS_NO_MEMORY },
                  { TDB_ERR_EXISTS,     NT_STATUS_OBJECT_NAME_COLLISION },

                  /*
                   * TDB_ERR_LOCK is very broad, we could for example
                   * distinguish between fcntl locks and invalid lock
                   * sequences. So NT_STATUS_FILE_LOCK_CONFLICT is a
                   * compromise.
                   */
                  { TDB_ERR_LOCK,       NT_STATUS_FILE_LOCK_CONFLICT },
                  /*
                   * The next two ones in the enum are not actually used
                   */
                  { TDB_ERR_NOLOCK,     NT_STATUS_FILE_LOCK_CONFLICT },
                  { TDB_ERR_LOCK_TIMEOUT, NT_STATUS_FILE_LOCK_CONFLICT },
                  { TDB_ERR_NOEXIST,    NT_STATUS_NOT_FOUND },
                  { TDB_ERR_EINVAL,     NT_STATUS_INVALID_PARAMETER },
                  { TDB_ERR_RDONLY,     NT_STATUS_ACCESS_DENIED }
                };

        int i;

        for (i=0; i < sizeof(map) / sizeof(map[0]); i++) {
                if (err == map[i].err) {
                        return map[i].status;
                }
        }

        return NT_STATUS_INTERNAL_ERROR;
}


/*********************************************************************
 * the following is a generic validation mechanism for tdbs.
 *********************************************************************/

/* 
 * internal validation function, executed by the child.  
 */
static int tdb_validate_child(struct tdb_context *tdb,
                              tdb_validate_data_func validate_fn)
{
        int ret = 1;
        int num_entries = 0;
        struct tdb_validation_status v_status;

        v_status.tdb_error = False;
        v_status.bad_freelist = False;
        v_status.bad_entry = False;
        v_status.unknown_key = False;
        v_status.success = True;

        if (!tdb) {
                v_status.tdb_error = True;
                v_status.success = False;
                goto out;
        }

        /* Check if the tdb's freelist is good. */
        if (tdb_validate_freelist(tdb, &num_entries) == -1) {
                v_status.bad_freelist = True;
                v_status.success = False;
                goto out;
        }

        DEBUG(10,("tdb_validate_child: tdb %s freelist has %d entries\n",
                  tdb_name(tdb), num_entries));

        /* Now traverse the tdb to validate it. */
        num_entries = tdb_traverse(tdb, validate_fn, (void *)&v_status);
        if (!v_status.success) {
                goto out;
        } else if (num_entries == -1) {
                v_status.tdb_error = True;
                v_status.success = False;
                goto out;
        }

        DEBUG(10,("tdb_validate_child: tdb %s is good with %d entries\n",
                  tdb_name(tdb), num_entries));
        ret = 0; /* Cache is good. */

out:
        DEBUG(10,   ("tdb_validate_child: summary of validation status:\n"));
        DEBUGADD(10,(" * tdb error: %s\n", v_status.tdb_error ? "yes" : "no"));
        DEBUGADD(10,(" * bad freelist: %s\n",v_status.bad_freelist?"yes":"no"));
        DEBUGADD(10,(" * bad entry: %s\n", v_status.bad_entry ? "yes" : "no"));
        DEBUGADD(10,(" * unknown key: %s\n", v_status.unknown_key?"yes":"no"));
        DEBUGADD(10,(" => overall success: %s\n", v_status.success?"yes":"no"));

        return ret;
}

/*
 * tdb validation function.
 * returns 0 if tdb is ok, != 0 if it isn't.
 * this function expects an opened tdb.
 */
int tdb_validate(struct tdb_context *tdb, tdb_validate_data_func validate_fn)
{
        pid_t child_pid = -1;
        int child_status = 0;
        int wait_pid = 0;
        int ret = 1;

        if (tdb == NULL) {
                DEBUG(1, ("Error: tdb_validate called with tdb == NULL\n"));
                return ret;
        }

        DEBUG(5, ("tdb_validate called for tdb '%s'\n", tdb_name(tdb)));

        /* fork and let the child do the validation.
         * benefit: no need to twist signal handlers and panic functions.
         * just let the child panic. we catch the signal. */

        DEBUG(10, ("tdb_validate: forking to let child do validation.\n"));
        child_pid = sys_fork();
        if (child_pid == 0) {
                /* child code */
                DEBUG(10, ("tdb_validate (validation child): created\n"));
                DEBUG(10, ("tdb_validate (validation child): "
                           "calling tdb_validate_child\n"));
                exit(tdb_validate_child(tdb, validate_fn));
        }
        else if (child_pid < 0) {
                DEBUG(1, ("tdb_validate: fork for validation failed.\n"));
                goto done;
        }

        /* parent */

        DEBUG(10, ("tdb_validate: fork succeeded, child PID = %d\n",child_pid));

        DEBUG(10, ("tdb_validate: waiting for child to finish...\n"));
        while  ((wait_pid = sys_waitpid(child_pid, &child_status, 0)) < 0) {
                if (errno == EINTR) {
                        DEBUG(10, ("tdb_validate: got signal during waitpid, "
                                   "retrying\n"));
                        errno = 0;
                        continue;
                }
                DEBUG(1, ("tdb_validate: waitpid failed with error '%s'.\n",
                          strerror(errno)));
                goto done;
        }
        if (wait_pid != child_pid) {
                DEBUG(1, ("tdb_validate: waitpid returned pid %d, "
                          "but %d was expected\n", wait_pid, child_pid));
                goto done;
        }

        DEBUG(10, ("tdb_validate: validating child returned.\n"));
        if (WIFEXITED(child_status)) {
                DEBUG(10, ("tdb_validate: child exited, code %d.\n",
                           WEXITSTATUS(child_status)));
                ret = WEXITSTATUS(child_status);
        }
        if (WIFSIGNALED(child_status)) {
                DEBUG(10, ("tdb_validate: child terminated by signal %d\n",
                           WTERMSIG(child_status)));
#ifdef WCOREDUMP
                if (WCOREDUMP(child_status)) {
                        DEBUGADD(10, ("core dumped\n"));
                }
#endif
                ret = WTERMSIG(child_status);
        }
        if (WIFSTOPPED(child_status)) {
                DEBUG(10, ("tdb_validate: child was stopped by signal %d\n",
                           WSTOPSIG(child_status)));
                ret = WSTOPSIG(child_status);
        }

done:
        DEBUG(5, ("tdb_validate returning code '%d' for tdb '%s'\n", ret,
                  tdb_name(tdb)));

        return ret;
}

/*
 * tdb validation function.
 * returns 0 if tdb is ok, != 0 if it isn't.
 * this is a wrapper around the actual validation function that opens and closes
 * the tdb.
 */
int tdb_validate_open(const char *tdb_path, tdb_validate_data_func validate_fn)
{
        TDB_CONTEXT *tdb = NULL;
        int ret = 1;

        DEBUG(5, ("tdb_validate_open called for tdb '%s'\n", tdb_path));

        tdb = tdb_open_log(tdb_path, 0, TDB_DEFAULT, O_RDONLY, 0);
        if (!tdb) {
                DEBUG(1, ("Error opening tdb %s\n", tdb_path));
                return ret;
        }

        ret = tdb_validate(tdb, validate_fn);
        tdb_close(tdb);
        return ret;
}

/*
 * tdb backup function and helpers for tdb_validate wrapper with backup
 * handling.
 */

/* this structure eliminates the need for a global overall status for
 * the traverse-copy */
struct tdb_copy_data {
        struct tdb_context *dst;
        bool success;
};

static int traverse_copy_fn(struct tdb_context *tdb, TDB_DATA key,
                            TDB_DATA dbuf, void *private_data)
{
        struct tdb_copy_data *data = (struct tdb_copy_data *)private_data;

        if (tdb_store(data->dst, key, dbuf, TDB_INSERT) != 0) {
                DEBUG(4, ("Failed to insert into %s: %s\n", tdb_name(data->dst),
                          strerror(errno)));
                data->success = False;
                return 1;
        }
        return 0;
}

static int tdb_copy(struct tdb_context *src, struct tdb_context *dst)
{
        struct tdb_copy_data data;
        int count;

        data.dst = dst;
        data.success = True;

        count = tdb_traverse(src, traverse_copy_fn, (void *)(&data));
        if ((count < 0) || (data.success == False)) {
                return -1;
        }
        return count;
}

static int tdb_verify_basic(struct tdb_context *tdb)
{
        return tdb_traverse(tdb, NULL, NULL);
}

/* this backup function is essentially taken from lib/tdb/tools/tdbbackup.tdb
 */
static int tdb_backup(TALLOC_CTX *ctx, const char *src_path,
                      const char *dst_path, int hash_size)
{
        struct tdb_context *src_tdb = NULL;
        struct tdb_context *dst_tdb = NULL;
        char *tmp_path = NULL;
        struct stat st;
        int count1, count2;
        int saved_errno = 0;
        int ret = -1;

        if (stat(src_path, &st) != 0) {
                DEBUG(3, ("Could not stat '%s': %s\n", src_path,
                          strerror(errno)));
                goto done;
        }

        /* open old tdb RDWR - so we can lock it */
        src_tdb = tdb_open_log(src_path, 0, TDB_DEFAULT, O_RDWR, 0);
        if (src_tdb == NULL) {
                DEBUG(3, ("Failed to open tdb '%s'\n", src_path));
                goto done;
        }

        if (tdb_lockall(src_tdb) != 0) {
                DEBUG(3, ("Failed to lock tdb '%s'\n", src_path));
                goto done;
        }

        tmp_path = talloc_asprintf(ctx, "%s%s", dst_path, ".tmp");
        unlink(tmp_path);
        dst_tdb = tdb_open_log(tmp_path,
                               hash_size ? hash_size : tdb_hash_size(src_tdb),
                               TDB_DEFAULT, O_RDWR | O_CREAT | O_EXCL,
                               st.st_mode & 0777);
        if (dst_tdb == NULL) {
                DEBUG(3, ("Error creating tdb '%s': %s\n", tmp_path,
                          strerror(errno)));
                saved_errno = errno;
                unlink(tmp_path);
                goto done;
        }

        count1 = tdb_copy(src_tdb, dst_tdb);
        if (count1 < 0) {
                DEBUG(3, ("Failed to copy tdb '%s': %s\n", src_path,
                          strerror(errno)));
                tdb_close(dst_tdb);
                goto done;
        }

        /* reopen ro and do basic verification */
        tdb_close(dst_tdb);
        dst_tdb = tdb_open_log(tmp_path, 0, TDB_DEFAULT, O_RDONLY, 0);
        if (!dst_tdb) {
                DEBUG(3, ("Failed to reopen tdb '%s': %s\n", tmp_path,
                          strerror(errno)));
                goto done;
        }
        count2 = tdb_verify_basic(dst_tdb);
        if (count2 != count1) {
                DEBUG(3, ("Failed to verify result of copying tdb '%s'.\n",
                          src_path));
                tdb_close(dst_tdb);
                goto done;
        }

        DEBUG(10, ("tdb_backup: successfully copied %d entries\n", count1));

        /* make sure the new tdb has reached stable storage
         * then rename it to its destination */
        fsync(tdb_fd(dst_tdb));
        tdb_close(dst_tdb);
        unlink(dst_path);
        if (rename(tmp_path, dst_path) != 0) {
                DEBUG(3, ("Failed to rename '%s' to '%s': %s\n",
                          tmp_path, dst_path, strerror(errno)));
                goto done;
        }

        /* success */
        ret = 0;

done:
        if (src_tdb != NULL) {
                tdb_close(src_tdb);
        }
        if (tmp_path != NULL) {
                unlink(tmp_path);
                TALLOC_FREE(tmp_path);
        }
        if (saved_errno != 0) {
                errno = saved_errno;
        }
        return ret;
}

static int rename_file_with_suffix(TALLOC_CTX *ctx, const char *path,
                                   const char *suffix)
{
        int ret = -1;
        char *dst_path;

        dst_path = talloc_asprintf(ctx, "%s%s", path, suffix);

        ret = (rename(path, dst_path) != 0);

        if (ret == 0) {
                DEBUG(5, ("moved '%s' to '%s'\n", path, dst_path));
        } else if (errno == ENOENT) {
                DEBUG(3, ("file '%s' does not exist - so not moved\n", path));
                ret = 0;
        } else {
                DEBUG(3, ("error renaming %s to %s: %s\n", path, dst_path,
                          strerror(errno)));
        }

        TALLOC_FREE(dst_path);
        return ret;
}

/*
 * do a backup of a tdb, moving the destination out of the way first
 */
static int tdb_backup_with_rotate(TALLOC_CTX *ctx, const char *src_path,
                                  const char *dst_path, int hash_size,
                                  const char *rotate_suffix,
                                  bool retry_norotate_if_nospc,
                                  bool rename_as_last_resort_if_nospc)
{
        int ret;

        rename_file_with_suffix(ctx, dst_path, rotate_suffix);

        ret = tdb_backup(ctx, src_path, dst_path, hash_size);

        if (ret != 0) {
                DEBUG(10, ("backup of %s failed: %s\n", src_path, strerror(errno)));
        }
        if ((ret != 0) && (errno == ENOSPC) && retry_norotate_if_nospc)
        {
                char *rotate_path = talloc_asprintf(ctx, "%s%s", dst_path,
                                                    rotate_suffix);
                DEBUG(10, ("backup of %s failed due to lack of space\n",
                           src_path));
                DEBUGADD(10, ("trying to free some space by removing rotated "
                              "dst %s\n", rotate_path));
                if (unlink(rotate_path) == -1) {
                        DEBUG(10, ("unlink of %s failed: %s\n", rotate_path,
                                   strerror(errno)));
                } else {
                        ret = tdb_backup(ctx, src_path, dst_path, hash_size);
                }
                TALLOC_FREE(rotate_path);
        }

        if ((ret != 0) && (errno == ENOSPC) && rename_as_last_resort_if_nospc)
        {
                DEBUG(10, ("backup of %s failed due to lack of space\n", 
                           src_path));
                DEBUGADD(10, ("using 'rename' as a last resort\n"));
                ret = rename(src_path, dst_path);
        }

        return ret;
}

/*
 * validation function with backup handling:
 *
 *  - calls tdb_validate
 *  - if the tdb is ok, create a backup "name.bak", possibly moving
 *    existing backup to name.bak.old,
 *    return 0 (success) even if the backup fails
 *  - if the tdb is corrupt:
 *    - move the tdb to "name.corrupt"
 *    - check if there is valid backup.
 *      if so, restore the backup.
 *      if restore is successful, return 0 (success),
 *    - otherwise return -1 (failure)
 */
int tdb_validate_and_backup(const char *tdb_path,
                            tdb_validate_data_func validate_fn)
{
        int ret = -1;
        const char *backup_suffix = ".bak";
        const char *corrupt_suffix = ".corrupt";
        const char *rotate_suffix = ".old";
        char *tdb_path_backup;
        struct stat st;
        TALLOC_CTX *ctx = NULL;

        ctx = talloc_new(NULL);
        if (ctx == NULL) {
                DEBUG(0, ("tdb_validate_and_backup: out of memory\n"));
                goto done;
        }

        tdb_path_backup = talloc_asprintf(ctx, "%s%s", tdb_path, backup_suffix);

        ret = tdb_validate_open(tdb_path, validate_fn);

        if (ret == 0) {
                DEBUG(1, ("tdb '%s' is valid\n", tdb_path));
                ret = tdb_backup_with_rotate(ctx, tdb_path, tdb_path_backup, 0,
                                             rotate_suffix, True, False);
                if (ret != 0) {
                        DEBUG(1, ("Error creating backup of tdb '%s'\n",
                                  tdb_path));
                        /* the actual validation was successful: */
                        ret = 0;
                } else {
                        DEBUG(1, ("Created backup '%s' of tdb '%s'\n",
                                  tdb_path_backup, tdb_path));
                }
        } else {
                DEBUG(1, ("tdb '%s' is invalid\n", tdb_path));

                ret =stat(tdb_path_backup, &st);
                if (ret != 0) {
                        DEBUG(5, ("Could not stat '%s': %s\n", tdb_path_backup,
                                  strerror(errno)));
                        DEBUG(1, ("No backup found.\n"));
                } else {
                        DEBUG(1, ("backup '%s' found.\n", tdb_path_backup));
                        ret = tdb_validate_open(tdb_path_backup, validate_fn);
                        if (ret != 0) {
                                DEBUG(1, ("Backup '%s' is invalid.\n",
                                          tdb_path_backup));
                        }
                }

                if (ret != 0) {
                        int renamed = rename_file_with_suffix(ctx, tdb_path,
                                                              corrupt_suffix);
                        if (renamed != 0) {
                                DEBUG(1, ("Error moving tdb to '%s%s'\n",
                                          tdb_path, corrupt_suffix));
                        } else {
                                DEBUG(1, ("Corrupt tdb stored as '%s%s'\n",
                                          tdb_path, corrupt_suffix));
                        }
                        goto done;
                }

                DEBUG(1, ("valid backup '%s' found\n", tdb_path_backup));
                ret = tdb_backup_with_rotate(ctx, tdb_path_backup, tdb_path, 0,
                                             corrupt_suffix, True, True);
                if (ret != 0) {
                        DEBUG(1, ("Error restoring backup from '%s'\n",
                                  tdb_path_backup));
                } else {
                        DEBUG(1, ("Restored tdb backup from '%s'\n",
                                  tdb_path_backup));
                }
        }

done:
        TALLOC_FREE(ctx);
        return ret;
}