source: branches/samba-3.3.x/source/winbindd/idmap_tdb2.c

/* 
   Unix SMB/CIFS implementation.

   idmap TDB2 backend, used for clustered Samba setups.

   This uses dbwrap to access tdb files. The location can be set
   using tdb:idmap2.tdb =" in smb.conf

   Copyright (C) Andrew Tridgell 2007

   This is heavily based upon idmap_tdb.c, which is:

   Copyright (C) Tim Potter 2000
   Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2003
   Copyright (C) Jeremy Allison 2006
   Copyright (C) Simo Sorce 2003-2006
   
   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 2 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"
#include "winbindd.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_IDMAP

/* High water mark keys */
#define HWM_GROUP  "GROUP HWM"
#define HWM_USER   "USER HWM"

static struct idmap_tdb2_state {
        /* User and group id pool */
        uid_t low_uid, high_uid;               /* Range of uids to allocate */
        gid_t low_gid, high_gid;               /* Range of gids to allocate */
        const char *idmap_script;
} idmap_tdb2_state;



/* handle to the permanent tdb */
static struct db_context *idmap_tdb2;

static NTSTATUS idmap_tdb2_alloc_load(void);

/*
  open the permanent tdb
 */
static NTSTATUS idmap_tdb2_open_db(void)
{
        char *db_path;
        
        if (idmap_tdb2) {
                /* its already open */
                return NT_STATUS_OK;
        }

        db_path = lp_parm_talloc_string(-1, "tdb", "idmap2.tdb", NULL);
        if (db_path == NULL) {
                /* fall back to the private directory, which, despite
                   its name, is usually on shared storage */
                db_path = talloc_asprintf(NULL, "%s/idmap2.tdb", lp_private_dir());
        }
        NT_STATUS_HAVE_NO_MEMORY(db_path);

        /* Open idmap repository */
        idmap_tdb2 = db_open(NULL, db_path, 0, TDB_DEFAULT, O_RDWR|O_CREAT, 0644);
        TALLOC_FREE(db_path);

        if (idmap_tdb2 == NULL) {
                DEBUG(0, ("Unable to open idmap_tdb2 database '%s'\n",
                          db_path));
                return NT_STATUS_UNSUCCESSFUL;
        }

        /* load the ranges and high/low water marks */
        return idmap_tdb2_alloc_load();
}


/*
  load the idmap allocation ranges and high/low water marks
*/
static NTSTATUS idmap_tdb2_alloc_load(void)
{
        uid_t low_uid = 0;
        uid_t high_uid = 0;
        gid_t low_gid = 0;
        gid_t high_gid = 0;
        uint32 low_id;

        /* see if a idmap script is configured */
        idmap_tdb2_state.idmap_script = lp_parm_const_string(-1, "idmap",
                                                             "script", NULL);

        if (idmap_tdb2_state.idmap_script) {
                DEBUG(1, ("using idmap script '%s'\n",
                          idmap_tdb2_state.idmap_script));
        }

        /* load ranges */

        /* Create high water marks for group and user id */
        if (!lp_idmap_uid(&low_uid, &high_uid)
            || !lp_idmap_gid(&low_gid, &high_gid)) {
                DEBUG(1, ("idmap uid or idmap gid missing\n"));
                return NT_STATUS_UNSUCCESSFUL;
        }

        idmap_tdb2_state.low_uid = low_uid;
        idmap_tdb2_state.high_uid = high_uid;
        idmap_tdb2_state.low_gid = low_gid;
        idmap_tdb2_state.high_gid = high_gid;

        if (idmap_tdb2_state.high_uid <= idmap_tdb2_state.low_uid) {
                DEBUG(1, ("idmap uid range missing or invalid\n"));
                DEBUGADD(1, ("idmap will be unable to map foreign SIDs\n"));
                return NT_STATUS_UNSUCCESSFUL;
        }

        if (((low_id = dbwrap_fetch_int32(idmap_tdb2,
                                          HWM_USER)) == -1) ||
            (low_id < idmap_tdb2_state.low_uid)) {
                if (!NT_STATUS_IS_OK(dbwrap_trans_store_int32(
                                             idmap_tdb2, HWM_USER,
                                             idmap_tdb2_state.low_uid))) {
                        DEBUG(0, ("Unable to initialise user hwm in idmap "
                                  "database\n"));
                        return NT_STATUS_INTERNAL_DB_ERROR;
                }
        }

        if (idmap_tdb2_state.high_gid <= idmap_tdb2_state.low_gid) {
                DEBUG(1, ("idmap gid range missing or invalid\n"));
                DEBUGADD(1, ("idmap will be unable to map foreign SIDs\n"));
                return NT_STATUS_UNSUCCESSFUL;
        }

        if (((low_id = dbwrap_fetch_int32(idmap_tdb2,
                                          HWM_GROUP)) == -1) ||
            (low_id < idmap_tdb2_state.low_gid)) {
                if (!NT_STATUS_IS_OK(dbwrap_trans_store_int32(
                                             idmap_tdb2, HWM_GROUP,
                                             idmap_tdb2_state.low_gid))) {
                        DEBUG(0, ("Unable to initialise group hwm in idmap "
                                  "database\n"));
                        return NT_STATUS_INTERNAL_DB_ERROR;
                }
        }

        return NT_STATUS_OK;
}


/*
  Initialise idmap alloc database. 
*/
static NTSTATUS idmap_tdb2_alloc_init(const char *params)
{
        /* nothing to do - we want to avoid opening the permanent
           database if possible. Instead we load the params when we
           first need it. */
        return NT_STATUS_OK;
}


/*
  Allocate a new id. 
*/
static NTSTATUS idmap_tdb2_allocate_id(struct unixid *xid)
{
        bool ret;
        const char *hwmkey;
        const char *hwmtype;
        uint32_t high_hwm;
        uint32_t hwm;
        int res;
        NTSTATUS status;

        status = idmap_tdb2_open_db();
        NT_STATUS_NOT_OK_RETURN(status);

        /* Get current high water mark */
        switch (xid->type) {

        case ID_TYPE_UID:
                hwmkey = HWM_USER;
                hwmtype = "UID";
                high_hwm = idmap_tdb2_state.high_uid;
                break;

        case ID_TYPE_GID:
                hwmkey = HWM_GROUP;
                hwmtype = "GID";
                high_hwm = idmap_tdb2_state.high_gid;
                break;

        default:
                DEBUG(2, ("Invalid ID type (0x%x)\n", xid->type));
                return NT_STATUS_INVALID_PARAMETER;
        }

        res = idmap_tdb2->transaction_start(idmap_tdb2);
        if (res != 0) {
                DEBUG(1,(__location__ " Failed to start transaction\n"));
                return NT_STATUS_UNSUCCESSFUL;
        }

        if ((hwm = dbwrap_fetch_int32(idmap_tdb2, hwmkey)) == -1) {
                idmap_tdb2->transaction_cancel(idmap_tdb2);
                return NT_STATUS_INTERNAL_DB_ERROR;
        }

        /* check it is in the range */
        if (hwm > high_hwm) {
                DEBUG(1, ("Fatal Error: %s range full!! (max: %lu)\n", 
                          hwmtype, (unsigned long)high_hwm));
                idmap_tdb2->transaction_cancel(idmap_tdb2);
                return NT_STATUS_UNSUCCESSFUL;
        }

        /* fetch a new id and increment it */
        ret = dbwrap_change_uint32_atomic(idmap_tdb2, hwmkey, &hwm, 1);
        if (ret == -1) {
                DEBUG(1, ("Fatal error while fetching a new %s value\n!", hwmtype));
                idmap_tdb2->transaction_cancel(idmap_tdb2);
                return NT_STATUS_UNSUCCESSFUL;
        }

        /* recheck it is in the range */
        if (hwm > high_hwm) {
                DEBUG(1, ("Fatal Error: %s range full!! (max: %lu)\n", 
                          hwmtype, (unsigned long)high_hwm));
                idmap_tdb2->transaction_cancel(idmap_tdb2);
                return NT_STATUS_UNSUCCESSFUL;
        }

        res = idmap_tdb2->transaction_commit(idmap_tdb2);
        if (res != 0) {
                DEBUG(1,(__location__ " Failed to commit transaction\n"));
                return NT_STATUS_UNSUCCESSFUL;
        }
        
        xid->id = hwm;
        DEBUG(10,("New %s = %d\n", hwmtype, hwm));

        return NT_STATUS_OK;
}

/*
  Get current highest id. 
*/
static NTSTATUS idmap_tdb2_get_hwm(struct unixid *xid)
{
        const char *hwmkey;
        const char *hwmtype;
        uint32_t hwm;
        uint32_t high_hwm;
        NTSTATUS status;

        status = idmap_tdb2_open_db();
        NT_STATUS_NOT_OK_RETURN(status);

        /* Get current high water mark */
        switch (xid->type) {

        case ID_TYPE_UID:
                hwmkey = HWM_USER;
                hwmtype = "UID";
                high_hwm = idmap_tdb2_state.high_uid;
                break;

        case ID_TYPE_GID:
                hwmkey = HWM_GROUP;
                hwmtype = "GID";
                high_hwm = idmap_tdb2_state.high_gid;
                break;

        default:
                return NT_STATUS_INVALID_PARAMETER;
        }

        if ((hwm = dbwrap_fetch_int32(idmap_tdb2, hwmkey)) == -1) {
                return NT_STATUS_INTERNAL_DB_ERROR;
        }

        xid->id = hwm;

        /* Warn if it is out of range */
        if (hwm >= high_hwm) {
                DEBUG(0, ("Warning: %s range full!! (max: %lu)\n", 
                          hwmtype, (unsigned long)high_hwm));
        }

        return NT_STATUS_OK;
}

/*
  Set high id. 
*/
static NTSTATUS idmap_tdb2_set_hwm(struct unixid *xid)
{
        /* not supported, or we would invalidate the cache tdb on
           other nodes */
        DEBUG(0,("idmap_tdb2_set_hwm not supported\n"));
        return NT_STATUS_NOT_SUPPORTED;
}

/*
  Close the alloc tdb 
*/
static NTSTATUS idmap_tdb2_alloc_close(void)
{
        /* don't actually close it */
        return NT_STATUS_OK;
}

/*
  IDMAP MAPPING TDB BACKEND
*/
struct idmap_tdb2_context {
        uint32_t filter_low_id;
        uint32_t filter_high_id;
};

/*
  Initialise idmap database. 
*/
static NTSTATUS idmap_tdb2_db_init(struct idmap_domain *dom,
                                   const char *params)
{
        NTSTATUS ret;
        struct idmap_tdb2_context *ctx;
        NTSTATUS status;

        status = idmap_tdb2_open_db();
        NT_STATUS_NOT_OK_RETURN(status);

        ctx = talloc(dom, struct idmap_tdb2_context);
        if ( ! ctx) {
                DEBUG(0, ("Out of memory!\n"));
                return NT_STATUS_NO_MEMORY;
        }

        if (strequal(dom->name, "*")) {
                uid_t low_uid = 0;
                uid_t high_uid = 0;
                gid_t low_gid = 0;
                gid_t high_gid = 0;

                ctx->filter_low_id = 0;
                ctx->filter_high_id = 0;

                if (lp_idmap_uid(&low_uid, &high_uid)) {
                        ctx->filter_low_id = low_uid;
                        ctx->filter_high_id = high_uid;
                } else {
                        DEBUG(3, ("Warning: 'idmap uid' not set!\n"));
                }

                if (lp_idmap_gid(&low_gid, &high_gid)) {
                        if ((low_gid != low_uid) || (high_gid != high_uid)) {
                                DEBUG(1, ("Warning: 'idmap uid' and 'idmap gid'"
                                      " ranges do not agree -- building "
                                      "intersection\n"));
                                ctx->filter_low_id = MAX(ctx->filter_low_id,
                                                         low_gid);
                                ctx->filter_high_id = MIN(ctx->filter_high_id,
                                                          high_gid);
                        }
                } else {
                        DEBUG(3, ("Warning: 'idmap gid' not set!\n"));
                }
        } else {
                char *config_option = NULL;
                const char *range;
                config_option = talloc_asprintf(ctx, "idmap config %s", dom->name);
                if ( ! config_option) {
                        DEBUG(0, ("Out of memory!\n"));
                        ret = NT_STATUS_NO_MEMORY;
                        goto failed;
                }

                range = lp_parm_const_string(-1, config_option, "range", NULL);
                if (( ! range) ||
                    (sscanf(range, "%u - %u", &ctx->filter_low_id, &ctx->filter_high_id) != 2))
                {
                        ctx->filter_low_id = 0;
                        ctx->filter_high_id = 0;
                }

                talloc_free(config_option);
        }

        if (ctx->filter_low_id > ctx->filter_high_id) {
                ctx->filter_low_id = 0;
                ctx->filter_high_id = 0;
        }

        dom->private_data = ctx;

        return NT_STATUS_OK;

failed:
        talloc_free(ctx);
        return ret;
}


/*
  run a script to perform a mapping

  The script should the following command lines:

      SIDTOID S-1-xxxx
      IDTOSID UID xxxx
      IDTOSID GID xxxx

  and should return one of the following as a single line of text
     UID:xxxx
     GID:xxxx
     SID:xxxx
     ERR:xxxx
 */
static NTSTATUS idmap_tdb2_script(struct idmap_tdb2_context *ctx, struct id_map *map,
                                  const char *fmt, ...)
{
        va_list ap;
        char *cmd;
        FILE *p;
        char line[64];
        unsigned long v;

        cmd = talloc_asprintf(ctx, "%s ", idmap_tdb2_state.idmap_script);
        NT_STATUS_HAVE_NO_MEMORY(cmd);  

        va_start(ap, fmt);
        cmd = talloc_vasprintf_append(cmd, fmt, ap);
        va_end(ap);
        NT_STATUS_HAVE_NO_MEMORY(cmd);

        p = popen(cmd, "r");
        talloc_free(cmd);
        if (p == NULL) {
                return NT_STATUS_NONE_MAPPED;
        }

        if (fgets(line, sizeof(line)-1, p) == NULL) {
                pclose(p);
                return NT_STATUS_NONE_MAPPED;
        }
        pclose(p);

        DEBUG(10,("idmap script gave: %s\n", line));

        if (sscanf(line, "UID:%lu", &v) == 1) {
                map->xid.id   = v;
                map->xid.type = ID_TYPE_UID;
        } else if (sscanf(line, "GID:%lu", &v) == 1) {
                map->xid.id   = v;
                map->xid.type = ID_TYPE_GID;            
        } else if (strncmp(line, "SID:S-", 6) == 0) {
                if (!string_to_sid(map->sid, &line[4])) {
                        DEBUG(0,("Bad SID in '%s' from idmap script %s\n",
                                 line, idmap_tdb2_state.idmap_script));
                        return NT_STATUS_NONE_MAPPED;                   
                }
        } else {
                DEBUG(0,("Bad reply '%s' from idmap script %s\n",
                         line, idmap_tdb2_state.idmap_script));
                return NT_STATUS_NONE_MAPPED;
        }

        return NT_STATUS_OK;
}



/*
  Single id to sid lookup function. 
*/
static NTSTATUS idmap_tdb2_id_to_sid(struct idmap_tdb2_context *ctx, struct id_map *map)
{
        NTSTATUS ret;
        TDB_DATA data;
        char *keystr;
        NTSTATUS status;

        status = idmap_tdb2_open_db();
        NT_STATUS_NOT_OK_RETURN(status);

        if (!ctx || !map) {
                return NT_STATUS_INVALID_PARAMETER;
        }

        /* apply filters before checking */
        if ((ctx->filter_low_id && (map->xid.id < ctx->filter_low_id)) ||
            (ctx->filter_high_id && (map->xid.id > ctx->filter_high_id))) {
                DEBUG(5, ("Requested id (%u) out of range (%u - %u). Filtered!\n",
                                map->xid.id, ctx->filter_low_id, ctx->filter_high_id));
                return NT_STATUS_NONE_MAPPED;
        }

        switch (map->xid.type) {

        case ID_TYPE_UID:
                keystr = talloc_asprintf(ctx, "UID %lu", (unsigned long)map->xid.id);
                break;
                
        case ID_TYPE_GID:
                keystr = talloc_asprintf(ctx, "GID %lu", (unsigned long)map->xid.id);
                break;

        default:
                DEBUG(2, ("INVALID unix ID type: 0x02%x\n", map->xid.type));
                return NT_STATUS_INVALID_PARAMETER;
        }

        /* final SAFE_FREE safe */
        data.dptr = NULL;

        if (keystr == NULL) {
                DEBUG(0, ("Out of memory!\n"));
                ret = NT_STATUS_NO_MEMORY;
                goto done;
        }

        DEBUG(10,("Fetching record %s\n", keystr));

        /* Check if the mapping exists */
        data = dbwrap_fetch_bystring(idmap_tdb2, keystr, keystr);

        if (!data.dptr) {
                fstring sidstr;

                DEBUG(10,("Record %s not found\n", keystr));
                if (idmap_tdb2_state.idmap_script == NULL) {
                        ret = NT_STATUS_NONE_MAPPED;
                        goto done;
                }

                ret = idmap_tdb2_script(ctx, map, "IDTOSID %s", keystr);

                /* store it on shared storage */
                if (!NT_STATUS_IS_OK(ret)) {
                        goto done;
                }

                if (sid_to_fstring(sidstr, map->sid)) {
                        /* both forward and reverse mappings */
                        dbwrap_store_bystring(idmap_tdb2, keystr,
                                            string_term_tdb_data(sidstr), 
                                            TDB_REPLACE);
                        dbwrap_store_bystring(idmap_tdb2, sidstr,
                                            string_term_tdb_data(keystr), 
                                            TDB_REPLACE);
                }
                goto done;
        }
                
        if (!string_to_sid(map->sid, (const char *)data.dptr)) {
                DEBUG(10,("INVALID SID (%s) in record %s\n",
                        (const char *)data.dptr, keystr));
                ret = NT_STATUS_INTERNAL_DB_ERROR;
                goto done;
        }

        DEBUG(10,("Found record %s -> %s\n", keystr, (const char *)data.dptr));
        ret = NT_STATUS_OK;

done:
        talloc_free(keystr);
        return ret;
}


/*
 Single sid to id lookup function. 
*/
static NTSTATUS idmap_tdb2_sid_to_id(struct idmap_tdb2_context *ctx, struct id_map *map)
{
        NTSTATUS ret;
        TDB_DATA data;
        char *keystr;
        unsigned long rec_id = 0;
        NTSTATUS status;

        status = idmap_tdb2_open_db();
        NT_STATUS_NOT_OK_RETURN(status);

        if ((keystr = sid_string_talloc(ctx, map->sid)) == NULL) {
                DEBUG(0, ("Out of memory!\n"));
                ret = NT_STATUS_NO_MEMORY;
                goto done;
        }

        DEBUG(10,("Fetching record %s\n", keystr));

        /* Check if sid is present in database */
        data = dbwrap_fetch_bystring(idmap_tdb2, keystr, keystr);
        if (!data.dptr) {
                fstring idstr;

                DEBUG(10,(__location__ " Record %s not found\n", keystr));

                if (idmap_tdb2_state.idmap_script == NULL) {
                        ret = NT_STATUS_NONE_MAPPED;
                        goto done;
                }
                        
                ret = idmap_tdb2_script(ctx, map, "SIDTOID %s", keystr);
                /* store it on shared storage */
                if (!NT_STATUS_IS_OK(ret)) {
                        goto done;
                }

                snprintf(idstr, sizeof(idstr), "%cID %lu", 
                         map->xid.type == ID_TYPE_UID?'U':'G',
                         (unsigned long)map->xid.id);
                /* store both forward and reverse mappings */
                dbwrap_store_bystring(idmap_tdb2, keystr, string_term_tdb_data(idstr),
                                    TDB_REPLACE);
                dbwrap_store_bystring(idmap_tdb2, idstr, string_term_tdb_data(keystr),
                                    TDB_REPLACE);
                goto done;
        }

        /* What type of record is this ? */
        if (sscanf((const char *)data.dptr, "UID %lu", &rec_id) == 1) { /* Try a UID record. */
                map->xid.id = rec_id;
                map->xid.type = ID_TYPE_UID;
                DEBUG(10,("Found uid record %s -> %s \n", keystr, (const char *)data.dptr ));
                ret = NT_STATUS_OK;

        } else if (sscanf((const char *)data.dptr, "GID %lu", &rec_id) == 1) { /* Try a GID record. */
                map->xid.id = rec_id;
                map->xid.type = ID_TYPE_GID;
                DEBUG(10,("Found gid record %s -> %s \n", keystr, (const char *)data.dptr ));
                ret = NT_STATUS_OK;

        } else { /* Unknown record type ! */
                DEBUG(2, ("Found INVALID record %s -> %s\n", keystr, (const char *)data.dptr));
                ret = NT_STATUS_INTERNAL_DB_ERROR;
        }
        
        /* apply filters before returning result */
        if ((ctx->filter_low_id && (map->xid.id < ctx->filter_low_id)) ||
            (ctx->filter_high_id && (map->xid.id > ctx->filter_high_id))) {
                DEBUG(5, ("Requested id (%u) out of range (%u - %u). Filtered!\n",
                                map->xid.id, ctx->filter_low_id, ctx->filter_high_id));
                ret = NT_STATUS_NONE_MAPPED;
        }

done:
        talloc_free(keystr);
        return ret;
}

/*
  lookup a set of unix ids. 
*/
static NTSTATUS idmap_tdb2_unixids_to_sids(struct idmap_domain *dom, struct id_map **ids)
{
        struct idmap_tdb2_context *ctx;
        NTSTATUS ret;
        int i;

        /* initialize the status to avoid suprise */
        for (i = 0; ids[i]; i++) {
                ids[i]->status = ID_UNKNOWN;
        }
        
        ctx = talloc_get_type(dom->private_data, struct idmap_tdb2_context);

        for (i = 0; ids[i]; i++) {
                ret = idmap_tdb2_id_to_sid(ctx, ids[i]);
                if ( ! NT_STATUS_IS_OK(ret)) {

                        /* if it is just a failed mapping continue */
                        if (NT_STATUS_EQUAL(ret, NT_STATUS_NONE_MAPPED)) {

                                /* make sure it is marked as unmapped */
                                ids[i]->status = ID_UNMAPPED;
                                continue;
                        }
                        
                        /* some fatal error occurred, return immediately */
                        goto done;
                }

                /* all ok, id is mapped */
                ids[i]->status = ID_MAPPED;
        }

        ret = NT_STATUS_OK;

done:
        return ret;
}

/*
  lookup a set of sids. 
*/
static NTSTATUS idmap_tdb2_sids_to_unixids(struct idmap_domain *dom, struct id_map **ids)
{
        struct idmap_tdb2_context *ctx;
        NTSTATUS ret;
        int i;

        /* initialize the status to avoid suprise */
        for (i = 0; ids[i]; i++) {
                ids[i]->status = ID_UNKNOWN;
        }
        
        ctx = talloc_get_type(dom->private_data, struct idmap_tdb2_context);

        for (i = 0; ids[i]; i++) {
                ret = idmap_tdb2_sid_to_id(ctx, ids[i]);
                if ( ! NT_STATUS_IS_OK(ret)) {

                        /* if it is just a failed mapping continue */
                        if (NT_STATUS_EQUAL(ret, NT_STATUS_NONE_MAPPED)) {

                                /* make sure it is marked as unmapped */
                                ids[i]->status = ID_UNMAPPED;
                                continue;
                        }
                        
                        /* some fatal error occurred, return immediately */
                        goto done;
                }

                /* all ok, id is mapped */
                ids[i]->status = ID_MAPPED;
        }

        ret = NT_STATUS_OK;

done:
        return ret;
}


/*
  set a mapping. 
*/
static NTSTATUS idmap_tdb2_set_mapping(struct idmap_domain *dom, const struct id_map *map)
{
        struct idmap_tdb2_context *ctx;
        NTSTATUS ret;
        TDB_DATA data;
        char *ksidstr, *kidstr;
        int res;
        bool started_transaction = false;

        if (!map || !map->sid) {
                return NT_STATUS_INVALID_PARAMETER;
        }

        ksidstr = kidstr = NULL;

        /* TODO: should we filter a set_mapping using low/high filters ? */
        
        ctx = talloc_get_type(dom->private_data, struct idmap_tdb2_context);

        switch (map->xid.type) {

        case ID_TYPE_UID:
                kidstr = talloc_asprintf(ctx, "UID %lu", (unsigned long)map->xid.id);
                break;
                
        case ID_TYPE_GID:
                kidstr = talloc_asprintf(ctx, "GID %lu", (unsigned long)map->xid.id);
                break;

        default:
                DEBUG(2, ("INVALID unix ID type: 0x02%x\n", map->xid.type));
                return NT_STATUS_INVALID_PARAMETER;
        }

        if (kidstr == NULL) {
                DEBUG(0, ("ERROR: Out of memory!\n"));
                ret = NT_STATUS_NO_MEMORY;
                goto done;
        }

        if (!(ksidstr = sid_string_talloc(ctx, map->sid))) {
                DEBUG(0, ("Out of memory!\n"));
                ret = NT_STATUS_NO_MEMORY;
                goto done;
        }

        DEBUG(10, ("Storing %s <-> %s map\n", ksidstr, kidstr));

        res = idmap_tdb2->transaction_start(idmap_tdb2);
        if (res != 0) {
                DEBUG(1,(__location__ " Failed to start transaction\n"));
                ret = NT_STATUS_UNSUCCESSFUL;
                goto done;
        }

        started_transaction = true;
        
        /* check wheter sid mapping is already present in db */
        data = dbwrap_fetch_bystring(idmap_tdb2, ksidstr, ksidstr);
        if (data.dptr) {
                ret = NT_STATUS_OBJECT_NAME_COLLISION;
                goto done;
        }

        ret = dbwrap_store_bystring(idmap_tdb2, ksidstr, string_term_tdb_data(kidstr),
                                  TDB_INSERT);
        if (!NT_STATUS_IS_OK(ret)) {
                DEBUG(0, ("Error storing SID -> ID: %s\n", nt_errstr(ret)));
                goto done;
        }
        ret = dbwrap_store_bystring(idmap_tdb2, kidstr, string_term_tdb_data(ksidstr),
                                  TDB_INSERT);
        if (!NT_STATUS_IS_OK(ret)) {
                DEBUG(0, ("Error storing ID -> SID: %s\n", nt_errstr(ret)));
                /* try to remove the previous stored SID -> ID map */
                dbwrap_delete_bystring(idmap_tdb2, ksidstr);
                goto done;
        }

        started_transaction = false;

        res = idmap_tdb2->transaction_commit(idmap_tdb2);
        if (res != 0) {
                DEBUG(1,(__location__ " Failed to commit transaction\n"));
                ret = NT_STATUS_UNSUCCESSFUL;
                goto done;
        }

        DEBUG(10,("Stored %s <-> %s\n", ksidstr, kidstr));
        ret = NT_STATUS_OK;

done:
        if (started_transaction) {
                idmap_tdb2->transaction_cancel(idmap_tdb2);
        }
        talloc_free(ksidstr);
        talloc_free(kidstr);
        return ret;
}

/*
  remove a mapping. 
*/
static NTSTATUS idmap_tdb2_remove_mapping(struct idmap_domain *dom, const struct id_map *map)
{
        /* not supported as it would invalidate the cache tdb on other
           nodes */
        DEBUG(0,("idmap_tdb2_remove_mapping not supported\n"));
        return NT_STATUS_NOT_SUPPORTED;
}

/*
  Close the idmap tdb instance
*/
static NTSTATUS idmap_tdb2_close(struct idmap_domain *dom)
{
        /* don't do anything */
        return NT_STATUS_OK;
}


/*
  Dump all mappings out
*/
static NTSTATUS idmap_tdb2_dump_data(struct idmap_domain *dom, struct id_map **maps, int *num_maps)
{
        DEBUG(0,("idmap_tdb2_dump_data not supported\n"));
        return NT_STATUS_NOT_SUPPORTED;
}

static struct idmap_methods db_methods = {
        .init            = idmap_tdb2_db_init,
        .unixids_to_sids = idmap_tdb2_unixids_to_sids,
        .sids_to_unixids = idmap_tdb2_sids_to_unixids,
        .set_mapping     = idmap_tdb2_set_mapping,
        .remove_mapping  = idmap_tdb2_remove_mapping,
        .dump_data       = idmap_tdb2_dump_data,
        .close_fn        = idmap_tdb2_close
};

static struct idmap_alloc_methods db_alloc_methods = {
        .init        = idmap_tdb2_alloc_init,
        .allocate_id = idmap_tdb2_allocate_id,
        .get_id_hwm  = idmap_tdb2_get_hwm,
        .set_id_hwm  = idmap_tdb2_set_hwm,
        .close_fn    = idmap_tdb2_alloc_close
};

NTSTATUS idmap_tdb2_init(void)
{
        NTSTATUS ret;

        /* register both backends */
        ret = smb_register_idmap_alloc(SMB_IDMAP_INTERFACE_VERSION, "tdb2", &db_alloc_methods);
        if (! NT_STATUS_IS_OK(ret)) {
                DEBUG(0, ("Unable to register idmap alloc tdb2 module: %s\n", get_friendly_nt_error_msg(ret)));
                return ret;
        }

        return smb_register_idmap(SMB_IDMAP_INTERFACE_VERSION, "tdb2", &db_methods);
}