res_config_odbc.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2010, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * Copyright (C) 2004 - 2005 Anthony Minessale II <anthmct@yahoo.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*! \file
 *
 * \brief odbc+odbc plugin for portable configuration engine
 *
 * \author Mark Spencer <markster@digium.com>
 * \author Anthony Minessale II <anthmct@yahoo.com>
 *
 * \arg http://www.unixodbc.org
 */
 
/*** MODULEINFO
    <depend>res_odbc</depend>
    <depend>generic_odbc</depend>
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/file.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/lock.h"
#include "asterisk/res_odbc.h"
#include "asterisk/utils.h"
#include "asterisk/stringfields.h"
 
/*! Initial SQL query buffer size to allocate. */
#define SQL_BUF_SIZE    1024
 
static const char *res_config_odbc_conf = "res_config_odbc.conf";
static int order_multi_row_results_by_initial_column = 1;
 
AST_THREADSTORAGE(sql_buf);
AST_THREADSTORAGE(rowdata_buf);
 
struct custom_prepare_struct {
    const char *sql;
    const char *extra;
    AST_DECLARE_STRING_FIELDS(
        AST_STRING_FIELD(encoding)[256];
    );
    const struct ast_variable *fields;
    unsigned long long skip;
};
 
#define ENCODE_CHUNK(buffer, s) \
    do { \
        char *eptr = buffer; \
        const char *vptr = s; \
        for (; *vptr && eptr < buffer + sizeof(buffer); vptr++) { \
            if (strchr("^;", *vptr)) { \
                /* We use ^XX, instead of %XX because '%' is a special character in SQL */ \
                snprintf(eptr, buffer + sizeof(buffer) - eptr, "^%02hhX", *vptr); \
                eptr += 3; \
            } else { \
                *eptr++ = *vptr; \
            } \
        } \
        if (eptr < buffer + sizeof(buffer)) { \
            *eptr = '\0'; \
        } else { \
            buffer[sizeof(buffer) - 1] = '\0'; \
        } \
    } while(0)
 
static void decode_chunk(char *chunk)
{
    for (; *chunk; chunk++) {
        if (*chunk == '^' && strchr("0123456789ABCDEF", chunk[1]) && strchr("0123456789ABCDEF", chunk[2])) {
            sscanf(chunk + 1, "%02hhX", (unsigned char *)chunk);
            memmove(chunk + 1, chunk + 3, strlen(chunk + 3) + 1);
        }
    }
}
 
static inline int is_text(const struct odbc_cache_columns *column)
{
    return column->type == SQL_CHAR || column->type == SQL_VARCHAR || column->type == SQL_LONGVARCHAR
        || column->type == SQL_WCHAR || column->type == SQL_WVARCHAR || column->type == SQL_WLONGVARCHAR;
}
 
static SQLHSTMT custom_prepare(struct odbc_obj *obj, void *data)
{
    int res, x = 1, count = 0;
    struct custom_prepare_struct *cps = data;
    const struct ast_variable *field;
    char encodebuf[1024];
    SQLHSTMT stmt;
 
    res = SQLAllocHandle(SQL_HANDLE_STMT, obj->con, &stmt);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL Alloc Handle failed!\n");
        return NULL;
    }
 
    ast_debug(1, "Skip: %llu; SQL: %s\n", cps->skip, cps->sql);
 
    res = ast_odbc_prepare(obj, stmt, cps->sql);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        if (res == SQL_ERROR) {
            ast_odbc_print_errors(SQL_HANDLE_STMT, stmt, "SQL Prepare");
        }
        ast_log(LOG_WARNING, "SQL Prepare failed! [%s]\n", cps->sql);
        SQLFreeHandle (SQL_HANDLE_STMT, stmt);
        return NULL;
    }
 
    for (field = cps->fields; field; field = field->next) {
        const char *newval = field->value;
 
        if ((1LL << count++) & cps->skip) {
            ast_debug(1, "Skipping field '%s'='%s' (%llo/%llo)\n", field->name, newval, 1ULL << (count - 1), cps->skip);
            continue;
        }
        ast_debug(1, "Parameter %d ('%s') = '%s'\n", x, field->name, newval);
        if (strchr(newval, ';') || strchr(newval, '^')) {
            ENCODE_CHUNK(encodebuf, newval);
            ast_string_field_set(cps, encoding[x], encodebuf);
            newval = cps->encoding[x];
        }
        SQLBindParameter(stmt, x++, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_CHAR, strlen(newval), 0, (void *)newval, 0, NULL);
    }
 
    if (!ast_strlen_zero(cps->extra)) {
        const char *newval = cps->extra;
        ast_debug(1, "Parameter %d = '%s'\n", x, newval);
        if (strchr(newval, ';') || strchr(newval, '^')) {
            ENCODE_CHUNK(encodebuf, newval);
            ast_string_field_set(cps, encoding[x], encodebuf);
            newval = cps->encoding[x];
        }
        SQLBindParameter(stmt, x++, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_CHAR, strlen(newval), 0, (void *)newval, 0, NULL);
    }
 
    return stmt;
}
 
/*!
 * \brief Execute an SQL query and return ast_variable list
 * \param database
 * \param table
 * \param fields list containing one or more field/operator/value set.
 *
 * Select database and preform query on table, prepare the sql statement
 * Sub-in the values to the prepared statement and execute it. Return results
 * as a ast_variable list.
 *
 * \return var on success (data found)
 * \return CONFIG_RT_NOT_FOUND on success but no record
 * \retval NULL on failure
 */
static struct ast_variable *realtime_odbc(const char *database, const char *table, const struct ast_variable *fields)
{
    struct odbc_obj *obj;
    SQLHSTMT stmt;
    char coltitle[256];
    struct ast_str *sql = ast_str_thread_get(&sql_buf, SQL_BUF_SIZE);
    struct ast_str *rowdata = ast_str_thread_get(&rowdata_buf, 128);
    char *op;
    const struct ast_variable *field = fields;
    char *stringp;
    char *chunk;
    SQLSMALLINT collen;
    int res;
    int x;
    struct ast_variable *var=NULL, *prev=NULL;
    SQLULEN colsize;
    SQLSMALLINT colcount=0;
    SQLSMALLINT datatype;
    SQLSMALLINT decimaldigits;
    SQLSMALLINT nullable;
    SQLLEN indicator;
    struct custom_prepare_struct cps = { .fields = fields, };
    struct ast_flags connected_flag = { RES_ODBC_CONNECTED };
 
    if (!table || !field || !sql || !rowdata) {
        return NULL;
    }
 
    obj = ast_odbc_request_obj2(database, connected_flag);
    if (!obj) {
        ast_log(LOG_ERROR, "No database handle available with the name of '%s' (check res_odbc.conf)\n", database);
        return NULL;
    }
 
    op = !strchr(field->name, ' ') ? " =" : "";
    ast_str_set(&sql, 0, "SELECT * FROM %s WHERE %s%s ?%s", table, field->name, op,
        strcasestr(field->name, "LIKE") && !ast_odbc_backslash_is_escape(obj) ? " ESCAPE '\\\\'" : "");
    while ((field = field->next)) {
        op = !strchr(field->name, ' ') ? " =" : "";
        ast_str_append(&sql, 0, " AND %s%s ?%s", field->name, op,
            strcasestr(field->name, "LIKE") && !ast_odbc_backslash_is_escape(obj) ? " ESCAPE '\\\\'" : "");
    }
 
    cps.sql = ast_str_buffer(sql);
 
    if (ast_string_field_init(&cps, 256)) {
        ast_odbc_release_obj(obj);
        return NULL;
    }
    stmt = ast_odbc_prepare_and_execute(obj, custom_prepare, &cps);
    ast_string_field_free_memory(&cps);
 
    if (!stmt) {
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    res = SQLNumResultCols(stmt, &colcount);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL Column Count error! [%s]\n", ast_str_buffer(sql));
        SQLFreeHandle (SQL_HANDLE_STMT, stmt);
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    res = SQLFetch(stmt);
    if (res == SQL_NO_DATA) {
        /* SQL_NO_DATA indicates that the query was valid but no record was found.
         * Instead of returning NULL (which signals a backend error to the core),
         * return CONFIG_RT_NOT_FOUND to prevent incorrect failover.
         */
        SQLFreeHandle (SQL_HANDLE_STMT, stmt);
        ast_odbc_release_obj(obj);
        return CONFIG_RT_NOT_FOUND;
    }
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL Fetch error! [%s]\n", ast_str_buffer(sql));
        SQLFreeHandle (SQL_HANDLE_STMT, stmt);
        ast_odbc_release_obj(obj);
        return NULL;
    }
    for (x = 0; x < colcount; x++) {
        colsize = 0;
        collen = sizeof(coltitle);
        res = SQLDescribeCol(stmt, x + 1, (unsigned char *)coltitle, sizeof(coltitle), &collen,
                    &datatype, &colsize, &decimaldigits, &nullable);
        if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
            ast_log(LOG_WARNING, "SQL Describe Column error! [%s]\n", ast_str_buffer(sql));
            if (var)
                ast_variables_destroy(var);
            ast_odbc_release_obj(obj);
            return NULL;
        }
 
        ast_str_reset(rowdata);
        indicator = 0;
 
        res = SQLGetData(stmt, x + 1, SQL_CHAR, ast_str_buffer(rowdata), ast_str_size(rowdata), &indicator);
        ast_str_update(rowdata);
        if (indicator == SQL_NULL_DATA) {
            ast_str_reset(rowdata);
        } else if (!ast_str_strlen(rowdata)) {
            /* Because we encode the empty string for a NULL, we will encode
             * actual empty strings as a string containing a single whitespace. */
            ast_str_set(&rowdata, -1, "%s", " ");
        } else if ((res == SQL_SUCCESS) || (res == SQL_SUCCESS_WITH_INFO)) {
            if (indicator != ast_str_strlen(rowdata)) {
                /* If the available space was not enough to contain the row data enlarge and read in the rest */
                ast_str_make_space(&rowdata, indicator + 1);
                res = SQLGetData(stmt, x + 1, SQL_CHAR, ast_str_buffer(rowdata) + ast_str_strlen(rowdata),
                    ast_str_size(rowdata) - ast_str_strlen(rowdata), &indicator);
                ast_str_update(rowdata);
            }
        }
 
        if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
            ast_log(LOG_WARNING, "SQL Get Data error! [%s]\n", ast_str_buffer(sql));
            if (var)
                ast_variables_destroy(var);
            ast_odbc_release_obj(obj);
            return NULL;
        }
 
        stringp = ast_str_buffer(rowdata);
        if (!strncmp(coltitle, "@", 1)) {
            /* The '@' prefix indicates it's a sorcery extended field.
             * Because ast_load_realtime_fields eliminates empty entries and makes blank (single whitespace)
             * entries empty and keeps them, the empty or NULL values are encoded
             * as a string containing a single whitespace. */
            if (prev) {
                prev->next = ast_variable_new(coltitle, S_OR(stringp," "), "");
                if (prev->next) {
                    prev = prev->next;
                }
            } else {
                prev = var = ast_variable_new(coltitle, S_OR(stringp," "), "");
            }
        } else {
            while (stringp) {
                chunk = strsep(&stringp, ";");
                if (!ast_strlen_zero(ast_strip(chunk))) {
                    if (strchr(chunk, '^')) {
                        decode_chunk(chunk);
                    }
                    if (prev) {
                        prev->next = ast_variable_new(coltitle, chunk, "");
                        if (prev->next) {
                            prev = prev->next;
                        }
                    } else {
                        prev = var = ast_variable_new(coltitle, chunk, "");
                    }
                }
            }
        }
    }
 
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
    ast_odbc_release_obj(obj);
    return var;
}
 
/*!
 * \brief Execute an Select query and return ast_config list
 * \param database
 * \param table
 * \param fields list containing one or more field/operator/value set.
 *
 * Select database and preform query on table, prepare the sql statement
 * Sub-in the values to the prepared statement and execute it.
 * Execute this prepared query against several ODBC connected databases.
 * Return results as an ast_config variable.
 *
 * \return var on success
 * \retval NULL on failure
 */
static struct ast_config *realtime_multi_odbc(const char *database, const char *table, const struct ast_variable *fields)
{
    struct odbc_obj *obj;
    SQLHSTMT stmt;
    char coltitle[256];
    struct ast_str *sql = ast_str_thread_get(&sql_buf, SQL_BUF_SIZE);
    struct ast_str *rowdata = ast_str_thread_get(&rowdata_buf, 128);
    const char *initfield;
    char *op;
    const struct ast_variable *field = fields;
    char *stringp;
    char *chunk;
    SQLSMALLINT collen;
    int res;
    int x;
    struct ast_variable *var=NULL;
    struct ast_config *cfg=NULL;
    struct ast_category *cat=NULL;
    struct ast_flags connected_flag = { RES_ODBC_CONNECTED };
    SQLULEN colsize;
    SQLSMALLINT colcount=0;
    SQLSMALLINT datatype;
    SQLSMALLINT decimaldigits;
    SQLSMALLINT nullable;
    SQLLEN indicator;
    struct custom_prepare_struct cps = { .fields = fields, };
 
    if (!table || !field || !sql || !rowdata) {
        return NULL;
    }
 
    obj = ast_odbc_request_obj2(database, connected_flag);
    if (!obj) {
        return NULL;
    }
 
    initfield = ast_strdupa(field->name);
    if ((op = strchr(initfield, ' '))) {
        *op = '\0';
    }
 
    op = !strchr(field->name, ' ') ? " =" : "";
    ast_str_set(&sql, 0, "SELECT * FROM %s WHERE %s%s ?%s", table, field->name, op,
        strcasestr(field->name, "LIKE") && !ast_odbc_backslash_is_escape(obj) ? " ESCAPE '\\\\'" : "");
    while ((field = field->next)) {
        op = !strchr(field->name, ' ') ? " =" : "";
        ast_str_append(&sql, 0, " AND %s%s ?%s", field->name, op,
            strcasestr(field->name, "LIKE") && !ast_odbc_backslash_is_escape(obj) ? " ESCAPE '\\\\'" : "");
    }
 
    if (order_multi_row_results_by_initial_column) {
        ast_str_append(&sql, 0, " ORDER BY %s", initfield);
    }
 
    cps.sql = ast_str_buffer(sql);
 
    if (ast_string_field_init(&cps, 256)) {
        ast_odbc_release_obj(obj);
        return NULL;
    }
    stmt = ast_odbc_prepare_and_execute(obj, custom_prepare, &cps);
    ast_string_field_free_memory(&cps);
 
    if (!stmt) {
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    res = SQLNumResultCols(stmt, &colcount);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL Column Count error! [%s]\n", ast_str_buffer(sql));
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    cfg = ast_config_new();
    if (!cfg) {
        ast_log(LOG_WARNING, "Out of memory!\n");
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    while ((res=SQLFetch(stmt)) != SQL_NO_DATA) {
        var = NULL;
        if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
            ast_log(LOG_WARNING, "SQL Fetch error! [%s]\n", ast_str_buffer(sql));
            continue;
        }
        cat = ast_category_new_anonymous();
        if (!cat) {
            continue;
        }
        for (x=0;x<colcount;x++) {
            colsize = 0;
            collen = sizeof(coltitle);
            res = SQLDescribeCol(stmt, x + 1, (unsigned char *)coltitle, sizeof(coltitle), &collen,
                        &datatype, &colsize, &decimaldigits, &nullable);
            if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
                ast_log(LOG_WARNING, "SQL Describe Column error! [%s]\n", ast_str_buffer(sql));
                ast_category_destroy(cat);
                goto next_sql_fetch;
            }
 
            ast_str_reset(rowdata);
            indicator = 0;
 
            res = SQLGetData(stmt, x + 1, SQL_CHAR, ast_str_buffer(rowdata), ast_str_size(rowdata), &indicator);
            ast_str_update(rowdata);
            if (indicator == SQL_NULL_DATA) {
                continue;
            }
 
            if ((res == SQL_SUCCESS) || (res == SQL_SUCCESS_WITH_INFO)) {
                if (indicator != ast_str_strlen(rowdata)) {
                    /* If the available space was not enough to contain the row data enlarge and read in the rest */
                    ast_str_make_space(&rowdata, indicator + 1);
                    res = SQLGetData(stmt, x + 1, SQL_CHAR, ast_str_buffer(rowdata) + ast_str_strlen(rowdata),
                        ast_str_size(rowdata) - ast_str_strlen(rowdata), &indicator);
                    ast_str_update(rowdata);
                }
            }
 
            if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
                ast_log(LOG_WARNING, "SQL Get Data error! [%s]\n", ast_str_buffer(sql));
                ast_category_destroy(cat);
                goto next_sql_fetch;
            }
            stringp = ast_str_buffer(rowdata);
            if (!strncmp(coltitle, "@", 1)) {
                /* The '@' prefix indicates it's a sorcery extended field.
                 * Because ast_load_realtime_fields eliminates empty entries and makes blank (single whitespace)
                 * entries empty and keeps them, the empty or NULL values are encoded
                 * as a string containing a single whitespace. */
                var = ast_variable_new(coltitle, S_OR(stringp," "), "");
                ast_variable_append(cat, var);
            } else {
                while (stringp) {
                    chunk = strsep(&stringp, ";");
                    if (!ast_strlen_zero(ast_strip(chunk))) {
                        if (strchr(chunk, '^')) {
                            decode_chunk(chunk);
                        }
                        if (!strcmp(initfield, coltitle)) {
                            ast_category_rename(cat, chunk);
                        }
                        var = ast_variable_new(coltitle, chunk, "");
                        ast_variable_append(cat, var);
                    }
                }
            }
        }
        ast_category_append(cfg, cat);
next_sql_fetch:;
    }
 
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
    ast_odbc_release_obj(obj);
    return cfg;
}
 
/*!
 * \brief Execute an UPDATE query
 * \param database
 * \param table
 * \param keyfield where clause field
 * \param lookup value of field for where clause
 * \param fields list containing one or more field/value set(s).
 *
 * Update a database table, prepare the sql statement using keyfield and lookup
 * control the number of records to change. All values to be changed are stored in ap list.
 * Sub-in the values to the prepared statement and execute it.
 *
 * \return number of rows affected
 * \retval -1 on failure
 */
static int update_odbc(const char *database, const char *table, const char *keyfield, const char *lookup, const struct ast_variable *fields)
{
    struct odbc_obj *obj;
    SQLHSTMT stmt;
    SQLLEN rowcount=0;
    struct ast_str *sql = ast_str_thread_get(&sql_buf, SQL_BUF_SIZE);
    const struct ast_variable *field = fields;
    int res, count = 0, paramcount = 0;
    struct custom_prepare_struct cps = { .extra = lookup, .fields = fields, };
    struct odbc_cache_tables *tableptr;
    struct odbc_cache_columns *column = NULL;
    struct ast_flags connected_flag = { RES_ODBC_CONNECTED };
 
    if (!table || !field || !keyfield || !sql) {
        return -1;
    }
 
    tableptr = ast_odbc_find_table(database, table);
    if (!(obj = ast_odbc_request_obj2(database, connected_flag))) {
        ast_odbc_release_table(tableptr);
        return -1;
    }
 
    if (tableptr && !ast_odbc_find_column(tableptr, keyfield)) {
        ast_log(LOG_WARNING, "Key field '%s' does not exist in table '%s@%s'.  Update will fail\n", keyfield, table, database);
    }
 
    ast_str_set(&sql, 0, "UPDATE %s SET ", table);
    while (field) {
        if ((tableptr && (column = ast_odbc_find_column(tableptr, field->name))) || count >= 64) {
            if (paramcount++) {
                ast_str_append(&sql, 0, ", ");
            }
            /* NULL test for non-text columns */
            if (count < 64 && ast_strlen_zero(field->value) && column->nullable && !is_text(column)) {
                ast_str_append(&sql, 0, "%s=NULL", field->name);
                cps.skip |= (1LL << count);
            } else {
                /* Value is not an empty string, or column is of text type, or we couldn't fit any more into cps.skip (count >= 64 ?!). */
                ast_str_append(&sql, 0, "%s=?", field->name);
            }
        } else { /* the column does not exist in the table */
            cps.skip |= (1LL << count);
        }
        ++count;
        field = field->next;
    }
    ast_str_append(&sql, 0, " WHERE %s=?", keyfield);
    ast_odbc_release_table(tableptr);
 
    cps.sql = ast_str_buffer(sql);
 
    if (ast_string_field_init(&cps, 256)) {
        ast_odbc_release_obj(obj);
        return -1;
    }
    stmt = ast_odbc_prepare_and_execute(obj, custom_prepare, &cps);
    ast_string_field_free_memory(&cps);
 
    if (!stmt) {
        ast_odbc_release_obj(obj);
        return -1;
    }
 
    res = SQLRowCount(stmt, &rowcount);
    SQLFreeHandle (SQL_HANDLE_STMT, stmt);
    ast_odbc_release_obj(obj);
 
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL Row Count error! [%s]\n", ast_str_buffer(sql));
        return -1;
    }
 
    if (rowcount >= 0) {
        return (int) rowcount;
    }
 
    return -1;
}
 
struct update2_prepare_struct {
    const char *database;
    const char *table;
    const struct ast_variable *lookup_fields;
    const struct ast_variable *update_fields;
    struct odbc_cache_tables *tableptr;
};
 
static SQLHSTMT update2_prepare(struct odbc_obj *obj, void *data)
{
    int res, x = 1, first = 1;
    struct update2_prepare_struct *ups = data;
    const struct ast_variable *field;
    struct ast_str *sql = ast_str_thread_get(&sql_buf, SQL_BUF_SIZE);
    SQLHSTMT stmt;
 
    if (!sql) {
        return NULL;
    }
 
    res = SQLAllocHandle(SQL_HANDLE_STMT, obj->con, &stmt);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL Alloc Handle failed!\n");
        return NULL;
    }
 
    ast_str_set(&sql, 0, "UPDATE %s SET ", ups->table);
 
    for (field = ups->update_fields; field; field = field->next) {
        if (ast_odbc_find_column(ups->tableptr, field->name)) {
            ast_str_append(&sql, 0, "%s%s=? ", first ? "" : ", ", field->name);
            SQLBindParameter(stmt, x++, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_CHAR, strlen(field->name), 0, (void *)field->value, 0, NULL);
            first = 0;
        } else {
            ast_log(LOG_NOTICE, "Not updating column '%s' in '%s@%s' because that column does not exist!\n", field->name, ups->table, ups->database);
        }
    }
 
    ast_str_append(&sql, 0, "WHERE");
    first = 1;
 
    for (field = ups->lookup_fields; field; field = field->next) {
        if (!ast_odbc_find_column(ups->tableptr, field->name)) {
            ast_log(LOG_ERROR, "One or more of the criteria columns '%s' on '%s@%s' for this update does not exist!\n", field->name, ups->table, ups->database);
            SQLFreeHandle(SQL_HANDLE_STMT, stmt);
            return NULL;
        }
        ast_str_append(&sql, 0, "%s %s=?", first ? "" : " AND", field->name);
        SQLBindParameter(stmt, x++, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_CHAR, strlen(field->value), 0, (void *)field->value, 0, NULL);
        first = 0;
    }
 
    res = ast_odbc_prepare(obj, stmt, ast_str_buffer(sql));
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        if (res == SQL_ERROR) {
            ast_odbc_print_errors(SQL_HANDLE_STMT, stmt, "SQL Prepare");
        }
        ast_log(LOG_WARNING, "SQL Prepare failed! [%s]\n", ast_str_buffer(sql));
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
        return NULL;
    }
 
    return stmt;
}
 
/*!
 * \brief Execute an UPDATE query
 * \param database, table, lookup_fields
 * \param update_fields list containing one or more field/value set(s).
 *
 * Update a database table, preparing the sql statement from a list of
 * key/value pairs specified in ap.  The lookup pairs are specified first
 * and are separated from the update pairs by a sentinel value.
 * Sub-in the values to the prepared statement and execute it.
 *
 * \return number of rows affected
 * \retval -1 on failure
*/
static int update2_odbc(const char *database, const char *table, const struct ast_variable *lookup_fields, const struct ast_variable *update_fields)
{
    struct odbc_obj *obj;
    SQLHSTMT stmt;
    struct update2_prepare_struct ups = {
        .database = database,
        .table = table,
        .lookup_fields = lookup_fields,
        .update_fields = update_fields,
    };
    struct ast_str *sql;
    int res;
    SQLLEN rowcount = 0;
 
    ups.tableptr = ast_odbc_find_table(database, table);
    if (!ups.tableptr) {
        ast_log(LOG_ERROR, "Could not retrieve metadata for table '%s@%s'. Update will fail!\n", table, database);
        return -1;
    }
 
    if (!(obj = ast_odbc_request_obj(database, 0))) {
        ast_odbc_release_table(ups.tableptr);
        return -1;
    }
 
    if (!(stmt = ast_odbc_prepare_and_execute(obj, update2_prepare, &ups))) {
        ast_odbc_release_obj(obj);
        ast_odbc_release_table(ups.tableptr);
        return -1;
    }
 
    /* We don't need the table anymore */
    ast_odbc_release_table(ups.tableptr);
 
    res = SQLRowCount(stmt, &rowcount);
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
    ast_odbc_release_obj(obj);
 
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        /* Since only a single thread can access this memory, we can retrieve what would otherwise be lost. */
        sql = ast_str_thread_get(&sql_buf, SQL_BUF_SIZE);
        ast_assert(sql != NULL);
        ast_log(LOG_WARNING, "SQL Row Count error! [%s]\n", ast_str_buffer(sql));
        return -1;
    }
 
    if (rowcount >= 0) {
        return (int) rowcount;
    }
 
    return -1;
}
 
/*!
 * \brief Execute an INSERT query
 * \param database
 * \param table
 * \param fields list containing one or more field/value set(s)
 *
 * Insert a new record into database table, prepare the sql statement.
 * All values to be changed are stored in ap list.
 * Sub-in the values to the prepared statement and execute it.
 *
 * \return number of rows affected
 * \retval -1 on failure
 */
static int store_odbc(const char *database, const char *table, const struct ast_variable *fields)
{
    struct odbc_obj *obj;
    SQLHSTMT stmt;
    SQLLEN rowcount=0;
    const struct ast_variable *field = fields;
    struct ast_str *keys;
    struct ast_str *vals;
    struct ast_str *sql = ast_str_thread_get(&sql_buf, SQL_BUF_SIZE);
    int res;
    struct custom_prepare_struct cps = { .fields = fields, };
    struct ast_flags connected_flag = { RES_ODBC_CONNECTED };
 
    keys = ast_str_create(SQL_BUF_SIZE / 2);
    vals = ast_str_create(SQL_BUF_SIZE / 4);
    if (!table || !field || !keys || !vals || !sql) {
        ast_free(vals);
        ast_free(keys);
        return -1;
    }
 
    obj = ast_odbc_request_obj2(database, connected_flag);
    if (!obj) {
        ast_free(vals);
        ast_free(keys);
        return -1;
    }
 
    ast_str_set(&keys, 0, "%s", field->name);
    ast_str_set(&vals, 0, "?");
    while ((field = field->next)) {
        ast_str_append(&keys, 0, ", %s", field->name);
        ast_str_append(&vals, 0, ", ?");
    }
    ast_str_set(&sql, 0, "INSERT INTO %s (%s) VALUES (%s)",
        table, ast_str_buffer(keys), ast_str_buffer(vals));
 
    ast_free(vals);
    ast_free(keys);
    cps.sql = ast_str_buffer(sql);
 
    if (ast_string_field_init(&cps, 256)) {
        ast_odbc_release_obj(obj);
        return -1;
    }
    stmt = ast_odbc_prepare_and_execute(obj, custom_prepare, &cps);
    ast_string_field_free_memory(&cps);
 
    if (!stmt) {
        ast_odbc_release_obj(obj);
        return -1;
    }
 
    res = SQLRowCount(stmt, &rowcount);
    SQLFreeHandle (SQL_HANDLE_STMT, stmt);
    ast_odbc_release_obj(obj);
 
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL Row Count error! [%s]\n", ast_str_buffer(sql));
        return -1;
    }
 
    if (rowcount >= 0)
        return (int)rowcount;
 
    return -1;
}
 
/*!
 * \brief Execute an DELETE query
 * \param database
 * \param table
 * \param keyfield where clause field
 * \param lookup value of field for where clause
 * \param fields list containing one or more field/value set(s)
 *
 * Delete a row from a database table, prepare the sql statement using keyfield and lookup
 * control the number of records to change. Additional params to match rows are stored in ap list.
 * Sub-in the values to the prepared statement and execute it.
 *
 * \return number of rows affected
 * \retval -1 on failure
 */
static int destroy_odbc(const char *database, const char *table, const char *keyfield, const char *lookup, const struct ast_variable *fields)
{
    struct odbc_obj *obj;
    SQLHSTMT stmt;
    SQLLEN rowcount=0;
    struct ast_str *sql = ast_str_thread_get(&sql_buf, SQL_BUF_SIZE);
    const struct ast_variable *field;
    int res;
    struct custom_prepare_struct cps = { .extra = lookup, .fields = fields, };
    struct ast_flags connected_flag = { RES_ODBC_CONNECTED };
 
    if (!table || !sql) {
        return -1;
    }
 
    obj = ast_odbc_request_obj2(database, connected_flag);
    if (!obj) {
        return -1;
    }
 
    ast_str_set(&sql, 0, "DELETE FROM %s WHERE ", table);
    for (field = fields; field; field = field->next) {
        ast_str_append(&sql, 0, "%s=? AND ", field->name);
    }
    ast_str_append(&sql, 0, "%s=?", keyfield);
 
    cps.sql = ast_str_buffer(sql);
 
    if (ast_string_field_init(&cps, 256)) {
        ast_odbc_release_obj(obj);
        return -1;
    }
    stmt = ast_odbc_prepare_and_execute(obj, custom_prepare, &cps);
    ast_string_field_free_memory(&cps);
 
    if (!stmt) {
        ast_odbc_release_obj(obj);
        return -1;
    }
 
    res = SQLRowCount(stmt, &rowcount);
    SQLFreeHandle (SQL_HANDLE_STMT, stmt);
    ast_odbc_release_obj(obj);
 
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL Row Count error! [%s]\n", ast_str_buffer(sql));
        return -1;
    }
 
    if (rowcount >= 0)
        return (int)rowcount;
 
    return -1;
}
 
struct config_odbc_obj {
    char *sql;
    unsigned long cat_metric;
    char category[128];
    char var_name[128];
    char *var_val;
    unsigned long var_val_size;
    SQLLEN err;
};
 
 
static SQLHSTMT length_determination_odbc_prepare(struct odbc_obj *obj, void *data)
{
    struct config_odbc_obj *q = data;
    SQLHSTMT sth;
    int res;
 
    res = SQLAllocHandle(SQL_HANDLE_STMT, obj->con, &sth);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_verb(4, "Failure in AllocStatement %d\n", res);
        return NULL;
    }
 
    res = ast_odbc_prepare(obj, sth, q->sql);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_verb(4, "Error in PREPARE %d\n", res);
        SQLFreeHandle(SQL_HANDLE_STMT, sth);
        return NULL;
    }
 
    SQLBindCol(sth, 1, SQL_C_ULONG, &q->var_val_size, sizeof(q->var_val_size), &q->err);
 
    return sth;
}
 
static SQLHSTMT config_odbc_prepare(struct odbc_obj *obj, void *data)
{
    struct config_odbc_obj *q = data;
    SQLHSTMT sth;
    int res;
 
    res = SQLAllocHandle(SQL_HANDLE_STMT, obj->con, &sth);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_verb(4, "Failure in AllocStatement %d\n", res);
        return NULL;
    }
 
    res = ast_odbc_prepare(obj, sth, q->sql);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_verb(4, "Error in PREPARE %d\n", res);
        SQLFreeHandle(SQL_HANDLE_STMT, sth);
        return NULL;
    }
 
    SQLBindCol(sth, 1, SQL_C_ULONG, &q->cat_metric, sizeof(q->cat_metric), &q->err);
    SQLBindCol(sth, 2, SQL_C_CHAR, q->category, sizeof(q->category), &q->err);
    SQLBindCol(sth, 3, SQL_C_CHAR, q->var_name, sizeof(q->var_name), &q->err);
    SQLBindCol(sth, 4, SQL_C_CHAR, q->var_val, q->var_val_size, &q->err);
 
    return sth;
}
 
static struct ast_config *config_odbc(const char *database, const char *table, const char *file, struct ast_config *cfg, struct ast_flags flags, const char *sugg_incl, const char *who_asked)
{
    struct ast_variable *new_v;
    struct ast_category *cur_cat;
    int res = 0;
    struct odbc_obj *obj;
    struct ast_str *sql = ast_str_thread_get(&sql_buf, SQL_BUF_SIZE);
    unsigned int last_cat_metric = 0;
    SQLSMALLINT rowcount = 0;
    SQLHSTMT stmt;
    char last[128] = "";
    struct config_odbc_obj q;
    struct ast_flags loader_flags = { 0 };
    struct ast_flags connected_flag = { RES_ODBC_CONNECTED };
 
    memset(&q, 0, sizeof(q));
 
    if (!file || !strcmp (file, res_config_odbc_conf) || !sql) {
        return NULL;        /* cant configure myself with myself ! */
    }
 
    obj = ast_odbc_request_obj2(database, connected_flag);
    if (!obj)
        return NULL;
 
    ast_str_set(&sql, 0, "SELECT MAX(LENGTH(var_val)) FROM %s WHERE filename='%s'",
        table, file);
    q.sql = ast_str_buffer(sql);
 
    stmt = ast_odbc_prepare_and_execute(obj, length_determination_odbc_prepare, &q);
    if (!stmt) {
        ast_log(LOG_WARNING, "SQL select error! [%s]\n", ast_str_buffer(sql));
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    res = SQLNumResultCols(stmt, &rowcount);
 
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL NumResultCols error! [%s]\n", ast_str_buffer(sql));
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    if (!rowcount) {
        ast_log(LOG_NOTICE, "found nothing\n");
        ast_odbc_release_obj(obj);
        return cfg;
    }
 
    /* There will be only one result for this, the maximum length of a variable value */
    if (SQLFetch(stmt) == SQL_NO_DATA) {
        ast_log(LOG_NOTICE, "Failed to determine maximum length of a configuration value\n");
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    /* Reset stuff to a fresh state for the actual query which will retrieve all configuration */
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
 
    ast_str_set(&sql, 0, "SELECT cat_metric, category, var_name, var_val FROM %s ", table);
    ast_str_append(&sql, 0, "WHERE filename='%s' AND commented=0 ", file);
    ast_str_append(&sql, 0, "ORDER BY cat_metric DESC, var_metric ASC, category, var_name ");
    q.sql = ast_str_buffer(sql);
 
    q.var_val_size += 1;
    q.var_val = ast_malloc(q.var_val_size);
    if (!q.var_val) {
        ast_log(LOG_WARNING, "Could not create buffer for reading in configuration values for '%s'\n", file);
        ast_odbc_release_obj(obj);
        return NULL;
    }
 
    stmt = ast_odbc_prepare_and_execute(obj, config_odbc_prepare, &q);
    if (!stmt) {
        ast_log(LOG_WARNING, "SQL select error! [%s]\n", ast_str_buffer(sql));
        ast_odbc_release_obj(obj);
        ast_free(q.var_val);
        return NULL;
    }
 
    res = SQLNumResultCols(stmt, &rowcount);
 
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "SQL NumResultCols error! [%s]\n", ast_str_buffer(sql));
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
        ast_odbc_release_obj(obj);
        ast_free(q.var_val);
        return NULL;
    }
 
    if (!rowcount) {
        ast_log(LOG_NOTICE, "found nothing\n");
        ast_odbc_release_obj(obj);
        ast_free(q.var_val);
        return cfg;
    }
 
    cur_cat = ast_config_get_current_category(cfg);
 
    while ((res = SQLFetch(stmt)) != SQL_NO_DATA) {
        if (!strcmp (q.var_name, "#include")) {
            if (!ast_config_internal_load(q.var_val, cfg, loader_flags, "", who_asked)) {
                SQLFreeHandle(SQL_HANDLE_STMT, stmt);
                ast_odbc_release_obj(obj);
                ast_free(q.var_val);
                return NULL;
            }
            continue;
        }
        if (strcmp(last, q.category) || last_cat_metric != q.cat_metric) {
            cur_cat = ast_category_new_dynamic(q.category);
            if (!cur_cat) {
                break;
            }
            strcpy(last, q.category);
            last_cat_metric = q.cat_metric;
            ast_category_append(cfg, cur_cat);
        }
 
        new_v = ast_variable_new(q.var_name, q.var_val, "");
        ast_variable_append(cur_cat, new_v);
    }
 
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
    ast_odbc_release_obj(obj);
    ast_free(q.var_val);
    return cfg;
}
 
#define warn_length(col, size)  ast_log(LOG_WARNING, "Realtime table %s@%s: column '%s' is not long enough to contain realtime data (needs %d)\n", table, database, col->name, size)
#define warn_type(col, type)    ast_log(LOG_WARNING, "Realtime table %s@%s: column '%s' is of the incorrect type (%d) to contain the required realtime data\n", table, database, col->name, col->type)
 
static int require_odbc(const char *database, const char *table, va_list ap)
{
    struct odbc_cache_tables *tableptr = ast_odbc_find_table(database, table);
    struct odbc_cache_columns *col;
    char *elm;
    int type, size;
 
    if (!tableptr) {
        return -1;
    }
 
    while ((elm = va_arg(ap, char *))) {
        type = va_arg(ap, require_type);
        size = va_arg(ap, int);
        /* Check if the field matches the criteria */
        AST_RWLIST_TRAVERSE(&tableptr->columns, col, list) {
            if (strcmp(col->name, elm) == 0) {
                /* Type check, first.  Some fields are more particular than others */
                switch (col->type) {
                case SQL_CHAR:
                case SQL_VARCHAR:
                case SQL_LONGVARCHAR:
#ifdef HAVE_ODBC_WCHAR
                case SQL_WCHAR:
                case SQL_WVARCHAR:
                case SQL_WLONGVARCHAR:
#endif
                case SQL_BINARY:
                case SQL_VARBINARY:
                case SQL_LONGVARBINARY:
                case SQL_GUID:
#define CHECK_SIZE(n) \
                        if (col->size < n) {      \
                            warn_length(col, n);  \
                        }                         \
                        break;
                    switch (type) {
                    case RQ_UINTEGER1: CHECK_SIZE(3)  /*         255 */
                    case RQ_INTEGER1:  CHECK_SIZE(4)  /*        -128 */
                    case RQ_UINTEGER2: CHECK_SIZE(5)  /*       65535 */
                    case RQ_INTEGER2:  CHECK_SIZE(6)  /*      -32768 */
                    case RQ_UINTEGER3:                /*    16777215 */
                    case RQ_INTEGER3:  CHECK_SIZE(8)  /*    -8388608 */
                    case RQ_DATE:                     /*  2008-06-09 */
                    case RQ_UINTEGER4: CHECK_SIZE(10) /*  4200000000 */
                    case RQ_INTEGER4:  CHECK_SIZE(11) /* -2100000000 */
                    case RQ_DATETIME:                 /* 2008-06-09 16:03:47 */
                    case RQ_UINTEGER8: CHECK_SIZE(19) /* trust me    */
                    case RQ_INTEGER8:  CHECK_SIZE(20) /* ditto       */
                    case RQ_FLOAT:
                    case RQ_CHAR:      CHECK_SIZE(size)
                    }
#undef CHECK_SIZE
                    break;
                case SQL_TYPE_DATE:
                    if (type != RQ_DATE) {
                        warn_type(col, type);
                    }
                    break;
                case SQL_TYPE_TIMESTAMP:
                case SQL_TIMESTAMP:
                case SQL_DATETIME:
                    if (type != RQ_DATE && type != RQ_DATETIME) {
                        warn_type(col, type);
                    }
                    break;
                case SQL_BIT:
                    warn_length(col, size);
                    break;
#define WARN_TYPE_OR_LENGTH(n)  \
                        if (!ast_rq_is_int(type)) {  \
                            warn_type(col, type);    \
                        } else {                     \
                            warn_length(col, n);  \
                        }
                case SQL_TINYINT:
                    if (type != RQ_UINTEGER1) {
                        WARN_TYPE_OR_LENGTH(size)
                    }
                    break;
                case SQL_C_STINYINT:
                    if (type != RQ_INTEGER1) {
                        WARN_TYPE_OR_LENGTH(size)
                    }
                    break;
                case SQL_C_USHORT:
                    if (type != RQ_UINTEGER1 && type != RQ_INTEGER1 && type != RQ_UINTEGER2) {
                        WARN_TYPE_OR_LENGTH(size)
                    }
                    break;
                case SQL_SMALLINT:
                case SQL_C_SSHORT:
                    if (type != RQ_UINTEGER1 && type != RQ_INTEGER1 && type != RQ_INTEGER2) {
                        WARN_TYPE_OR_LENGTH(size)
                    }
                    break;
                case SQL_C_ULONG:
                    if (type != RQ_UINTEGER1 && type != RQ_INTEGER1 &&
                        type != RQ_UINTEGER2 && type != RQ_INTEGER2 &&
                        type != RQ_UINTEGER3 && type != RQ_INTEGER3 &&
                        type != RQ_INTEGER4) {
                        WARN_TYPE_OR_LENGTH(size)
                    }
                    break;
                case SQL_INTEGER:
                case SQL_C_SLONG:
                    if (type != RQ_UINTEGER1 && type != RQ_INTEGER1 &&
                        type != RQ_UINTEGER2 && type != RQ_INTEGER2 &&
                        type != RQ_UINTEGER3 && type != RQ_INTEGER3 &&
                        type != RQ_INTEGER4) {
                        WARN_TYPE_OR_LENGTH(size)
                    }
                    break;
                case SQL_C_UBIGINT:
                    if (type != RQ_UINTEGER1 && type != RQ_INTEGER1 &&
                        type != RQ_UINTEGER2 && type != RQ_INTEGER2 &&
                        type != RQ_UINTEGER3 && type != RQ_INTEGER3 &&
                        type != RQ_UINTEGER4 && type != RQ_INTEGER4 &&
                        type != RQ_INTEGER8) {
                        WARN_TYPE_OR_LENGTH(size)
                    }
                    break;
                case SQL_BIGINT:
                case SQL_C_SBIGINT:
                    if (type != RQ_UINTEGER1 && type != RQ_INTEGER1 &&
                        type != RQ_UINTEGER2 && type != RQ_INTEGER2 &&
                        type != RQ_UINTEGER3 && type != RQ_INTEGER3 &&
                        type != RQ_UINTEGER4 && type != RQ_INTEGER4 &&
                        type != RQ_INTEGER8) {
                        WARN_TYPE_OR_LENGTH(size)
                    }
                    break;
#undef WARN_TYPE_OR_LENGTH
                case SQL_NUMERIC:
                case SQL_DECIMAL:
                case SQL_FLOAT:
                case SQL_REAL:
                case SQL_DOUBLE:
                    if (!ast_rq_is_int(type) && type != RQ_FLOAT) {
                        warn_type(col, type);
                    }
                    break;
                default:
                    ast_log(LOG_WARNING, "Realtime table %s@%s: column type (%d) unrecognized for column '%s'\n", table, database, col->type, elm);
                }
                break;
            }
        }
        if (!col) {
            ast_log(LOG_WARNING, "Realtime table %s@%s requires column '%s', but that column does not exist!\n", table, database, elm);
        }
    }
    AST_RWLIST_UNLOCK(&tableptr->columns);
    return 0;
}
#undef warn_length
#undef warn_type
 
static int unload_odbc(const char *a, const char *b)
{
    return ast_odbc_clear_cache(a, b);
}
 
static struct ast_config_engine odbc_engine = {
    .name = "odbc",
    .load_func = config_odbc,
    .realtime_func = realtime_odbc,
    .realtime_multi_func = realtime_multi_odbc,
    .store_func = store_odbc,
    .destroy_func = destroy_odbc,
    .update_func = update_odbc,
    .update2_func = update2_odbc,
    .require_func = require_odbc,
    .unload_func = unload_odbc,
};
 
static void load_config(const char *filename)
{
    struct ast_config *config;
    struct ast_flags config_flags = { 0 };
    const char *s;
 
    config = ast_config_load(filename, config_flags);
    if (config == CONFIG_STATUS_FILEMISSING || config == CONFIG_STATUS_FILEINVALID) {
        if (config == CONFIG_STATUS_FILEINVALID) {
            ast_log(LOG_WARNING, "Unable to load config '%s'. Using defaults.\n", filename);
        }
        order_multi_row_results_by_initial_column = 1;
        return;
    }
 
    /* Result set ordering is enabled by default */
    s = ast_variable_retrieve(config, "general", "order_multi_row_results_by_initial_column");
    order_multi_row_results_by_initial_column = !s || ast_true(s);
 
    ast_config_destroy(config);
}
 
static int load_module(void)
{
    /* We'll either successfully load the configuration or fail with reasonable
     * defaults */
    load_config(res_config_odbc_conf);
    ast_config_engine_register(&odbc_engine);
    return 0;
}
 
static int reload_module(void)
{
    load_config(res_config_odbc_conf);
    return 0;
}
 
static int unload_module(void)
{
    ast_config_engine_deregister(&odbc_engine);
    return 0;
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Realtime ODBC configuration",
    .support_level = AST_MODULE_SUPPORT_CORE,
    .load = load_module,
    .unload = unload_module,
    .reload = reload_module,
    .load_pri = AST_MODPRI_REALTIME_DRIVER,
    .requires = "extconfig,res_odbc",
);