r8224: - add objectGUID ldif_handler

[Samba/aatanasov.git] / source4 / dsdb / samdb / samdb.c

/* 
   Unix SMB/CIFS implementation.

   interface functions for the sam database

   Copyright (C) Andrew Tridgell 2004
   
   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 "librpc/gen_ndr/ndr_netlogon.h"
#include "lib/ldb/include/ldb.h"
#include "system/time.h"
#include "system/filesys.h"
#include "db_wrap.h"

/*
  connect to the SAM database
  return an opaque context pointer on success, or NULL on failure
 */
struct ldb_context *samdb_connect(TALLOC_CTX *mem_ctx)
{
        return ldb_wrap_connect(mem_ctx, lp_sam_url(), 0, NULL);
}

/*
  search the sam for the specified attributes in a specific domain, filter on
  objectSid being in domain_sid.
*/
int samdb_search_domain(struct ldb_context *sam_ldb,
                        TALLOC_CTX *mem_ctx, 
                        const char *basedn,
                        struct ldb_message ***res,
                        const char * const *attrs,
                        const struct dom_sid *domain_sid,
                        const char *format, ...)  _PRINTF_ATTRIBUTE(7,8)
{
        va_list ap;
        int i, count;

        va_start(ap, format);
        count = gendb_search_v(sam_ldb, mem_ctx, basedn,
                               res, attrs, format, ap);
        va_end(ap);

        i=0;

        while (i<count) {
                struct dom_sid *entry_sid;

                entry_sid = samdb_result_dom_sid(mem_ctx, (*res)[i], "objectSid");

                if ((entry_sid == NULL) ||
                    (!dom_sid_in_domain(domain_sid, entry_sid))) {
                        /* Delete that entry from the result set */
                        (*res)[i] = (*res)[count-1];
                        count -= 1;
                        talloc_free(entry_sid);
                        continue;
                }
                talloc_free(entry_sid);
                i += 1;
        }

        return count;
}

/*
  search the sam for a single string attribute in exactly 1 record
*/
const char *samdb_search_string_v(struct ldb_context *sam_ldb,
                                  TALLOC_CTX *mem_ctx,
                                  const char *basedn,
                                  const char *attr_name,
                                  const char *format, va_list ap) _PRINTF_ATTRIBUTE(5,0)
{
        int count;
        const char * const attrs[2] = { attr_name, NULL };
        struct ldb_message **res = NULL;

        count = gendb_search_v(sam_ldb, mem_ctx, basedn, &res, attrs, format, ap);
        if (count > 1) {                
                DEBUG(1,("samdb: search for %s %s not single valued (count=%d)\n", 
                         attr_name, format, count));
        }
        if (count != 1) {
                talloc_free(res);
                return NULL;
        }

        return samdb_result_string(res[0], attr_name, NULL);
}
                                 

/*
  search the sam for a single string attribute in exactly 1 record
*/
const char *samdb_search_string(struct ldb_context *sam_ldb,
                                TALLOC_CTX *mem_ctx,
                                const char *basedn,
                                const char *attr_name,
                                const char *format, ...) _PRINTF_ATTRIBUTE(5,6)
{
        va_list ap;
        const char *str;

        va_start(ap, format);
        str = samdb_search_string_v(sam_ldb, mem_ctx, basedn, attr_name, format, ap);
        va_end(ap);

        return str;
}

/*
  search the sam for a dom_sid attribute in exactly 1 record
*/
struct dom_sid *samdb_search_dom_sid(struct ldb_context *sam_ldb,
                                     TALLOC_CTX *mem_ctx,
                                     const char *basedn,
                                     const char *attr_name,
                                     const char *format, ...) _PRINTF_ATTRIBUTE(5,6)
{
        va_list ap;
        int count;
        struct ldb_message **res;
        const char * const attrs[2] = { attr_name, NULL };
        struct dom_sid *sid;

        va_start(ap, format);
        count = gendb_search_v(sam_ldb, mem_ctx, basedn, &res, attrs, format, ap);
        va_end(ap);
        if (count > 1) {                
                DEBUG(1,("samdb: search for %s %s not single valued (count=%d)\n", 
                         attr_name, format, count));
        }
        if (count != 1) {
                talloc_free(res);
                return NULL;
        }
        sid = samdb_result_dom_sid(mem_ctx, res[0], attr_name);
        talloc_free(res);
        return sid;     
}

/*
  return the count of the number of records in the sam matching the query
*/
int samdb_search_count(struct ldb_context *sam_ldb,
                       TALLOC_CTX *mem_ctx,
                       const char *basedn,
                       const char *format, ...) _PRINTF_ATTRIBUTE(4,5)
{
        va_list ap;
        struct ldb_message **res;
        const char * const attrs[] = { NULL };
        int ret;

        va_start(ap, format);
        ret = gendb_search_v(sam_ldb, mem_ctx, basedn, &res, attrs, format, ap);
        va_end(ap);

        return ret;
}


/*
  search the sam for a single integer attribute in exactly 1 record
*/
uint_t samdb_search_uint(struct ldb_context *sam_ldb,
                         TALLOC_CTX *mem_ctx,
                         uint_t default_value,
                         const char *basedn,
                         const char *attr_name,
                         const char *format, ...) _PRINTF_ATTRIBUTE(6,7)
{
        va_list ap;
        int count;
        struct ldb_message **res;
        const char * const attrs[2] = { attr_name, NULL };

        va_start(ap, format);
        count = gendb_search_v(sam_ldb, mem_ctx, basedn, &res, attrs, format, ap);
        va_end(ap);

        if (count != 1) {
                return default_value;
        }

        return samdb_result_uint(res[0], attr_name, default_value);
}

/*
  search the sam for a single signed 64 bit integer attribute in exactly 1 record
*/
int64_t samdb_search_int64(struct ldb_context *sam_ldb,
                           TALLOC_CTX *mem_ctx,
                           int64_t default_value,
                           const char *basedn,
                           const char *attr_name,
                           const char *format, ...) _PRINTF_ATTRIBUTE(6,7)
{
        va_list ap;
        int count;
        struct ldb_message **res;
        const char * const attrs[2] = { attr_name, NULL };

        va_start(ap, format);
        count = gendb_search_v(sam_ldb, mem_ctx, basedn, &res, attrs, format, ap);
        va_end(ap);

        if (count != 1) {
                return default_value;
        }

        return samdb_result_int64(res[0], attr_name, default_value);
}

/*
  search the sam for multipe records each giving a single string attribute
  return the number of matches, or -1 on error
*/
int samdb_search_string_multiple(struct ldb_context *sam_ldb,
                                 TALLOC_CTX *mem_ctx,
                                 const char *basedn,
                                 const char ***strs,
                                 const char *attr_name,
                                 const char *format, ...) _PRINTF_ATTRIBUTE(6,7)
{
        va_list ap;
        int count, i;
        const char * const attrs[2] = { attr_name, NULL };
        struct ldb_message **res = NULL;

        va_start(ap, format);
        count = gendb_search_v(sam_ldb, mem_ctx, basedn, &res, attrs, format, ap);
        va_end(ap);

        if (count <= 0) {
                return count;
        }

        /* make sure its single valued */
        for (i=0;i<count;i++) {
                if (res[i]->num_elements != 1) {
                        DEBUG(1,("samdb: search for %s %s not single valued\n", 
                                 attr_name, format));
                        talloc_free(res);
                        return -1;
                }
        }

        *strs = talloc_array(mem_ctx, const char *, count+1);
        if (! *strs) {
                talloc_free(res);
                return -1;
        }

        for (i=0;i<count;i++) {
                (*strs)[i] = samdb_result_string(res[i], attr_name, NULL);
        }
        (*strs)[count] = NULL;

        return count;
}

/*
  pull a uint from a result set. 
*/
uint_t samdb_result_uint(struct ldb_message *msg, const char *attr, uint_t default_value)
{
        return ldb_msg_find_uint(msg, attr, default_value);
}

/*
  pull a (signed) int64 from a result set. 
*/
int64_t samdb_result_int64(struct ldb_message *msg, const char *attr, int64_t default_value)
{
        return ldb_msg_find_int64(msg, attr, default_value);
}

/*
  pull a string from a result set. 
*/
const char *samdb_result_string(struct ldb_message *msg, const char *attr, 
                                const char *default_value)
{
        return ldb_msg_find_string(msg, attr, default_value);
}

/*
  pull a rid from a objectSid in a result set. 
*/
uint32_t samdb_result_rid_from_sid(TALLOC_CTX *mem_ctx, struct ldb_message *msg, 
                                   const char *attr, uint32_t default_value)
{
        struct dom_sid *sid;
        uint32_t rid;

        sid = samdb_result_dom_sid(mem_ctx, msg, attr);
        if (sid == NULL) {
                return default_value;
        }
        rid = sid->sub_auths[sid->num_auths-1];
        talloc_free(sid);
        return rid;
}

/*
  pull a dom_sid structure from a objectSid in a result set. 
*/
struct dom_sid *samdb_result_dom_sid(TALLOC_CTX *mem_ctx, struct ldb_message *msg, 
                                     const char *attr)
{
        const struct ldb_val *v;
        struct dom_sid *sid;
        NTSTATUS status;
        v = ldb_msg_find_ldb_val(msg, attr);
        if (v == NULL) {
                return NULL;
        }
        sid = talloc(mem_ctx, struct dom_sid);
        if (sid == NULL) {
                return NULL;
        }
        status = ndr_pull_struct_blob(v, sid, sid, 
                                      (ndr_pull_flags_fn_t)ndr_pull_dom_sid);
        if (!NT_STATUS_IS_OK(status)) {
                talloc_free(sid);
                return NULL;
        }
        return sid;
}

/*
  pull a guid structure from a objectGUID in a result set. 
*/
struct GUID samdb_result_guid(struct ldb_message *msg, const char *attr)
{
        const struct ldb_val *v;
        NTSTATUS status;
        struct GUID guid;
        TALLOC_CTX *mem_ctx;

        ZERO_STRUCT(guid);

        v = ldb_msg_find_ldb_val(msg, attr);
        if (!v) return guid;

        mem_ctx = talloc_named_const(NULL, 0, "samdb_result_guid");
        if (!mem_ctx) return guid;
        status = ndr_pull_struct_blob(v, mem_ctx, &guid, 
                                      (ndr_pull_flags_fn_t)ndr_pull_GUID);
        talloc_free(mem_ctx);
        if (!NT_STATUS_IS_OK(status)) {
                return guid;
        }

        return guid;
}

/*
  pull a sid prefix from a objectSid in a result set. 
  this is used to find the domain sid for a user
*/
struct dom_sid *samdb_result_sid_prefix(TALLOC_CTX *mem_ctx, struct ldb_message *msg, 
                                        const char *attr)
{
        struct dom_sid *sid = samdb_result_dom_sid(mem_ctx, msg, attr);
        if (!sid || sid->num_auths < 1) return NULL;
        sid->num_auths--;
        return sid;
}

/*
  pull a NTTIME in a result set. 
*/
NTTIME samdb_result_nttime(struct ldb_message *msg, const char *attr, const char *default_value)
{
        const char *str = ldb_msg_find_string(msg, attr, default_value);
        return nttime_from_string(str);
}

/*
  pull a uint64_t from a result set. 
*/
uint64_t samdb_result_uint64(struct ldb_message *msg, const char *attr, uint64_t default_value)
{
        return ldb_msg_find_uint64(msg, attr, default_value);
}


/*
  construct the allow_password_change field from the PwdLastSet attribute and the 
  domain password settings
*/
NTTIME samdb_result_allow_password_change(struct ldb_context *sam_ldb, 
                                          TALLOC_CTX *mem_ctx, 
                                          const char *domain_dn, 
                                          struct ldb_message *msg, 
                                          const char *attr)
{
        uint64_t attr_time = samdb_result_uint64(msg, attr, 0);
        int64_t minPwdAge;

        if (attr_time == 0) {
                return 0;
        }

        minPwdAge = samdb_search_int64(sam_ldb, mem_ctx, 0,
                                       domain_dn, "minPwdAge", NULL);

        /* yes, this is a -= not a += as minPwdAge is stored as the negative
           of the number of 100-nano-seconds */
        attr_time -= minPwdAge;

        return attr_time;
}

/*
  construct the force_password_change field from the PwdLastSet attribute and the 
  domain password settings
*/
NTTIME samdb_result_force_password_change(struct ldb_context *sam_ldb, 
                                          TALLOC_CTX *mem_ctx, 
                                          const char *domain_dn, 
                                          struct ldb_message *msg, 
                                          const char *attr)
{
        uint64_t attr_time = samdb_result_uint64(msg, attr, 0);
        int64_t maxPwdAge;

        if (attr_time == 0) {
                return 0;
        }

        maxPwdAge = samdb_search_int64(sam_ldb, mem_ctx, 0, domain_dn, "maxPwdAge", NULL);
        if (maxPwdAge == 0) {
                return 0;
        } else {
                attr_time -= maxPwdAge;
        }

        return attr_time;
}

/*
  pull a samr_Password structutre from a result set. 
*/
struct samr_Password samdb_result_hash(struct ldb_message *msg, const char *attr)
{
        struct samr_Password hash;
        const struct ldb_val *val = ldb_msg_find_ldb_val(msg, attr);
        ZERO_STRUCT(hash);
        if (val) {
                memcpy(hash.hash, val->data, MIN(val->length, sizeof(hash.hash)));
        }
        return hash;
}

/*
  pull an array of samr_Password structutres from a result set. 
*/
uint_t samdb_result_hashes(TALLOC_CTX *mem_ctx, struct ldb_message *msg, 
                           const char *attr, struct samr_Password **hashes)
{
        uint_t count = 0;
        const struct ldb_val *val = ldb_msg_find_ldb_val(msg, attr);
        int i;

        *hashes = NULL;
        if (!val) {
                return 0;
        }
        count = val->length / 16;
        if (count == 0) {
                return 0;
        }

        *hashes = talloc_array(mem_ctx, struct samr_Password, count);
        if (! *hashes) {
                return 0;
        }

        for (i=0;i<count;i++) {
                memcpy((*hashes)[i].hash, (i*16)+(char *)val->data, 16);
        }

        return count;
}

NTSTATUS samdb_result_passwords(TALLOC_CTX *mem_ctx, struct ldb_message *msg, 
                                struct samr_Password **lm_pwd, struct samr_Password **nt_pwd) 
{

        const char *unicodePwd = samdb_result_string(msg, "unicodePwd", NULL);
        
        struct samr_Password *lmPwdHash, *ntPwdHash;
        if (unicodePwd) {
                if (nt_pwd) {
                        ntPwdHash = talloc(mem_ctx, struct samr_Password);
                        if (!ntPwdHash) {
                                return NT_STATUS_NO_MEMORY;
                        }
                        
                        E_md4hash(unicodePwd, ntPwdHash->hash);
                        *nt_pwd = ntPwdHash;
                }

                if (lm_pwd) {
                        BOOL lm_hash_ok;
                
                        lmPwdHash = talloc(mem_ctx, struct samr_Password);
                        if (!lmPwdHash) {
                                return NT_STATUS_NO_MEMORY;
                        }
                        
                        /* compute the new nt and lm hashes */
                        lm_hash_ok = E_deshash(unicodePwd, lmPwdHash->hash);
                        
                        if (lm_hash_ok) {
                                *lm_pwd = lmPwdHash;
                        } else {
                                *lm_pwd = NULL;
                        }
                }
        } else {
                if (nt_pwd) {
                        int num_nt;
                        num_nt = samdb_result_hashes(mem_ctx, msg, "ntPwdHash", &ntPwdHash);
                        if (num_nt == 0) {
                                *nt_pwd = NULL;
                        } else if (num_nt > 1) {
                                return NT_STATUS_INTERNAL_DB_CORRUPTION;
                        } else {
                                *nt_pwd = &ntPwdHash[0];
                        }
                }
                if (lm_pwd) {
                        int num_lm;
                        num_lm = samdb_result_hashes(mem_ctx, msg, "lmPwdHash", &lmPwdHash);
                        if (num_lm == 0) {
                                *lm_pwd = NULL;
                        } else if (num_lm > 1) {
                                return NT_STATUS_INTERNAL_DB_CORRUPTION;
                        } else {
                                *lm_pwd = &lmPwdHash[0];
                        }
                }
                
        }
        return NT_STATUS_OK;
}

/*
  pull a samr_LogonHours structutre from a result set. 
*/
struct samr_LogonHours samdb_result_logon_hours(TALLOC_CTX *mem_ctx, struct ldb_message *msg, const char *attr)
{
        struct samr_LogonHours hours;
        const int units_per_week = 168;
        const struct ldb_val *val = ldb_msg_find_ldb_val(msg, attr);
        ZERO_STRUCT(hours);
        hours.bits = talloc_array(mem_ctx, uint8_t, units_per_week);
        if (!hours.bits) {
                return hours;
        }
        hours.units_per_week = units_per_week;
        memset(hours.bits, 0xFF, units_per_week);
        if (val) {
                memcpy(hours.bits, val->data, MIN(val->length, units_per_week));
        }
        return hours;
}

/*
  pull a set of account_flags from a result set. 
*/
uint16_t samdb_result_acct_flags(struct ldb_message *msg, const char *attr)
{
        uint_t userAccountControl = ldb_msg_find_uint(msg, attr, 0);
        return samdb_uf2acb(userAccountControl);
}

/*
  copy from a template record to a message
*/
int samdb_copy_template(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, 
                        struct ldb_message *msg, const char *expression)
{
        struct ldb_message **res, *t;
        int ret, i, j;
        

        /* pull the template record */
        ret = gendb_search(sam_ldb, mem_ctx, NULL, &res, NULL, "%s", expression);
        if (ret != 1) {
                DEBUG(1,("samdb: ERROR: template '%s' matched %d records\n", 
                         expression, ret));
                return -1;
        }
        t = res[0];

        for (i=0;i<t->num_elements;i++) {
                struct ldb_message_element *el = &t->elements[i];
                /* some elements should not be copied from the template */
                if (strcasecmp(el->name, "cn") == 0 ||
                    strcasecmp(el->name, "name") == 0 ||
                    strcasecmp(el->name, "sAMAccountName") == 0) {
                        continue;
                }
                for (j=0;j<el->num_values;j++) {
                        if (strcasecmp(el->name, "objectClass") == 0 &&
                            (strcasecmp((char *)el->values[j].data, "Template") == 0 ||
                             strcasecmp((char *)el->values[j].data, "userTemplate") == 0 ||
                             strcasecmp((char *)el->values[j].data, "groupTemplate") == 0 ||
                             strcasecmp((char *)el->values[j].data, "foreignSecurityTemplate") == 0 ||
                             strcasecmp((char *)el->values[j].data, "aliasTemplate") == 0 || 
                             strcasecmp((char *)el->values[j].data, "trustedDomainTemplate") == 0 || 
                             strcasecmp((char *)el->values[j].data, "secretTemplate") == 0)) {
                                continue;
                        }
                        samdb_msg_add_string(sam_ldb, mem_ctx, msg, el->name, 
                                             (char *)el->values[j].data);
                }
        }

        return 0;
}


/*
  allocate a new id, attempting to do it atomically
  return 0 on failure, the id on success
*/
static NTSTATUS _samdb_allocate_next_id(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, const char *dn, 
                                        const char *attr, uint32_t *id)
{
        struct ldb_message msg;
        int ret;
        const char *str;
        struct ldb_val vals[2];
        struct ldb_message_element els[2];

        str = samdb_search_string(sam_ldb, mem_ctx, dn, attr, NULL);
        if (!str) {
                DEBUG(1,("id not found at %s %s\n", dn, attr));
                return NT_STATUS_OBJECT_NAME_INVALID;
        }

        *id = strtol(str, NULL, 0);
        if ((*id)+1 == 0) {
                /* out of IDs ! */
                return NT_STATUS_INSUFFICIENT_RESOURCES;
        }

        /* we do a delete and add as a single operation. That prevents
           a race */
        ZERO_STRUCT(msg);
        msg.dn = talloc_strdup(mem_ctx, dn);
        if (!msg.dn) {
                return NT_STATUS_NO_MEMORY;
        }
        msg.num_elements = 2;
        msg.elements = els;

        els[0].num_values = 1;
        els[0].values = &vals[0];
        els[0].flags = LDB_FLAG_MOD_DELETE;
        els[0].name = talloc_strdup(mem_ctx, attr);
        if (!els[0].name) {
                return NT_STATUS_NO_MEMORY;
        }

        els[1].num_values = 1;
        els[1].values = &vals[1];
        els[1].flags = LDB_FLAG_MOD_ADD;
        els[1].name = els[0].name;

        vals[0].data = (uint8_t *)talloc_asprintf(mem_ctx, "%u", *id);
        if (!vals[0].data) {
                return NT_STATUS_NO_MEMORY;
        }
        vals[0].length = strlen((const char *)vals[0].data);

        vals[1].data =  (uint8_t *)talloc_asprintf(mem_ctx, "%u", (*id)+1);
        if (!vals[1].data) {
                return NT_STATUS_NO_MEMORY;
        }
        vals[1].length = strlen((const char *)vals[1].data);

        ret = ldb_modify(sam_ldb, &msg);
        if (ret != 0) {
                return NT_STATUS_UNEXPECTED_IO_ERROR;
        }

        (*id)++;

        return NT_STATUS_OK;
}

/*
  allocate a new id, attempting to do it atomically
  return 0 on failure, the id on success
*/
NTSTATUS samdb_allocate_next_id(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, const char *dn, const char *attr,
                                uint32_t *id)
{
        int tries = 10;
        NTSTATUS status;

        /* we need to try multiple times to cope with two account
           creations at the same time */
        while (tries--) {
                status = _samdb_allocate_next_id(sam_ldb, mem_ctx, dn, attr, id);
                if (!NT_STATUS_EQUAL(NT_STATUS_UNEXPECTED_IO_ERROR, status)) {
                        break;
                }
        }

        if (NT_STATUS_EQUAL(NT_STATUS_UNEXPECTED_IO_ERROR, status)) {
                DEBUG(1,("Failed to increment id %s at %s\n", attr, dn));
        }

        return status;
}


/*
  add a string element to a message
*/
int samdb_msg_add_string(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                         const char *attr_name, const char *str)
{
        char *s = talloc_strdup(mem_ctx, str);
        char *a = talloc_strdup(mem_ctx, attr_name);
        if (s == NULL || a == NULL) {
                return -1;
        }
        return ldb_msg_add_string(sam_ldb, msg, a, s);
}

/*
  add a dom_sid element to a message
*/
int samdb_msg_add_dom_sid(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                         const char *attr_name, struct dom_sid *sid)
{
        struct ldb_val v;
        NTSTATUS status;
        status = ndr_push_struct_blob(&v, mem_ctx, sid, 
                                      (ndr_push_flags_fn_t)ndr_push_dom_sid);
        if (!NT_STATUS_IS_OK(status)) {
                return -1;
        }
        return ldb_msg_add_value(sam_ldb, msg, attr_name, &v);
}


/*
  add a delete element operation to a message
*/
int samdb_msg_add_delete(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                         const char *attr_name)
{
        char *a = talloc_strdup(mem_ctx, attr_name);
        if (a == NULL) {
                return -1;
        }
        /* we use an empty replace rather than a delete, as it allows for 
           samdb_replace() to be used everywhere */
        return ldb_msg_add_empty(sam_ldb, msg, a, LDB_FLAG_MOD_REPLACE);
}

/*
  add a add attribute value to a message
*/
int samdb_msg_add_addval(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                         const char *attr_name, const char *value)
{
        struct ldb_message_element *el;
        char *a, *v;
        int ret;
        a = talloc_strdup(mem_ctx, attr_name);
        if (a == NULL)
                return -1;
        v = talloc_strdup(mem_ctx, value);
        if (v == NULL)
                return -1;
        ret = ldb_msg_add_string(sam_ldb, msg, a, v);
        if (ret != 0)
                return ret;
        el = ldb_msg_find_element(msg, a);
        if (el == NULL)
                return -1;
        el->flags = LDB_FLAG_MOD_ADD;
        return 0;
}

/*
  add a delete attribute value to a message
*/
int samdb_msg_add_delval(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                         const char *attr_name, const char *value)
{
        struct ldb_message_element *el;
        char *a, *v;
        int ret;
        a = talloc_strdup(mem_ctx, attr_name);
        if (a == NULL)
                return -1;
        v = talloc_strdup(mem_ctx, value);
        if (v == NULL)
                return -1;
        ret = ldb_msg_add_string(sam_ldb, msg, a, v);
        if (ret != 0)
                return ret;
        el = ldb_msg_find_element(msg, a);
        if (el == NULL)
                return -1;
        el->flags = LDB_FLAG_MOD_DELETE;
        return 0;
}

/*
  add a uint_t element to a message
*/
int samdb_msg_add_uint(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                       const char *attr_name, uint_t v)
{
        const char *s = talloc_asprintf(mem_ctx, "%u", v);
        return samdb_msg_add_string(sam_ldb, mem_ctx, msg, attr_name, s);
}

/*
  add a (signed) int64_t element to a message
*/
int samdb_msg_add_int64(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                        const char *attr_name, int64_t v)
{
        const char *s = talloc_asprintf(mem_ctx, "%lld", v);
        return samdb_msg_add_string(sam_ldb, mem_ctx, msg, attr_name, s);
}

/*
  add a uint64_t element to a message
*/
int samdb_msg_add_uint64(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                        const char *attr_name, uint64_t v)
{
        const char *s = talloc_asprintf(mem_ctx, "%llu", v);
        return samdb_msg_add_string(sam_ldb, mem_ctx, msg, attr_name, s);
}

/*
  add a samr_Password element to a message
*/
int samdb_msg_add_hash(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                       const char *attr_name, struct samr_Password *hash)
{
        struct ldb_val val;
        val.data = talloc_memdup(mem_ctx, hash->hash, 16);
        if (!val.data) {
                return -1;
        }
        val.length = 16;
        return ldb_msg_add_value(sam_ldb, msg, attr_name, &val);
}

/*
  add a samr_Password array to a message
*/
int samdb_msg_add_hashes(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                         const char *attr_name, struct samr_Password *hashes, uint_t count)
{
        struct ldb_val val;
        int i;
        val.data = talloc_array_size(mem_ctx, 16, count);
        val.length = count*16;
        if (!val.data) {
                return -1;
        }
        for (i=0;i<count;i++) {
                memcpy(i*16 + (char *)val.data, hashes[i].hash, 16);
        }
        return ldb_msg_add_value(sam_ldb, msg, attr_name, &val);
}

/*
  add a acct_flags element to a message
*/
int samdb_msg_add_acct_flags(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                             const char *attr_name, uint32_t v)
{
        return samdb_msg_add_uint(sam_ldb, mem_ctx, msg, attr_name, samdb_acb2uf(v));
}

/*
  add a logon_hours element to a message
*/
int samdb_msg_add_logon_hours(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                              const char *attr_name, struct samr_LogonHours *hours)
{
        struct ldb_val val;
        val.length = hours->units_per_week / 8;
        val.data = hours->bits;
        return ldb_msg_add_value(sam_ldb, msg, attr_name, &val);
}

/*
  add a general value element to a message
*/
int samdb_msg_add_value(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                              const char *attr_name, const struct ldb_val *val)
{
        return ldb_msg_add_value(sam_ldb, msg, attr_name, val);
}

/*
  sets a general value element to a message
*/
int samdb_msg_set_value(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                        const char *attr_name, const struct ldb_val *val)
{
        struct ldb_message_element *el;

        el = ldb_msg_find_element(msg, attr_name);
        if (el) {
                el->num_values = 0;
        }
        return ldb_msg_add_value(sam_ldb, msg, attr_name, val);
}

/*
  set a string element in a message
*/
int samdb_msg_set_string(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                         const char *attr_name, const char *str)
{
        struct ldb_message_element *el;

        el = ldb_msg_find_element(msg, attr_name);
        if (el) {
                el->num_values = 0;
        }
        return samdb_msg_add_string(sam_ldb, mem_ctx, msg, attr_name, str);
}

/*
  set a ldaptime element in a message
*/
int samdb_msg_set_ldaptime(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg,
                           const char *attr_name, time_t t)
{
        char *str = ldap_timestring(mem_ctx, t);
        if (!str) {
                return -1;
        }
        return samdb_msg_set_string(sam_ldb, mem_ctx, msg, attr_name, str);
}

/*
  add a record
*/
int samdb_add(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg)
{
        int ret;
        struct ldb_val v;
        NTSTATUS status;
        struct GUID guid = GUID_random();

        status = ndr_push_struct_blob(&v, mem_ctx, &guid, 
                                      (ndr_push_flags_fn_t)ndr_push_GUID);
        if (!NT_STATUS_IS_OK(status)) {
                return -1;
        }

        ret = ldb_msg_add_value(sam_ldb, msg, "objectGUID", &v);
        if (ret != 0) return ret;

        return ldb_add(sam_ldb, msg);
}

/*
  delete a record
*/
int samdb_delete(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, const char *dn)
{
        return ldb_delete(sam_ldb, dn);
}

/*
  modify a record
*/
int samdb_modify(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg)
{
        return ldb_modify(sam_ldb, msg);
}

/*
  replace elements in a record
*/
int samdb_replace(struct ldb_context *sam_ldb, TALLOC_CTX *mem_ctx, struct ldb_message *msg)
{
        int i;

        /* mark all the message elements as LDB_FLAG_MOD_REPLACE */
        for (i=0;i<msg->num_elements;i++) {
                msg->elements[i].flags = LDB_FLAG_MOD_REPLACE;
        }

        /* modify the samdb record */
        return samdb_modify(sam_ldb, mem_ctx, msg);
}

/*
  return a default security descriptor
*/
struct security_descriptor *samdb_default_security_descriptor(TALLOC_CTX *mem_ctx)
{
        struct security_descriptor *sd;

        sd = security_descriptor_initialise(mem_ctx);

        return sd;
}