res_odbc.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2012, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * res_odbc.c <ODBC resource manager>
 * 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 resource manager
 *
 * \author Mark Spencer <markster@digium.com>
 * \author Anthony Minessale II <anthmct@yahoo.com>
 * \author Tilghman Lesher <tilghman@digium.com>
 *
 * \arg See also: \ref cdr_odbc.c
 */
 
/*! \li \ref res_odbc.c uses the configuration file \ref res_odbc.conf
 * \addtogroup configuration_file Configuration Files
 */
 
/*!
 * \page res_odbc.conf res_odbc.conf
 * \verbinclude res_odbc.conf.sample
 */
 
/*** MODULEINFO
    <depend>generic_odbc</depend>
    <depend>res_odbc_transaction</depend>
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/file.h"
#include "asterisk/channel.h"
#include "asterisk/config.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/cli.h"
#include "asterisk/lock.h"
#include "asterisk/res_odbc.h"
#include "asterisk/time.h"
#include "asterisk/astobj2.h"
#include "asterisk/app.h"
#include "asterisk/strings.h"
#include "asterisk/threadstorage.h"
 
struct odbc_class
{
    AST_LIST_ENTRY(odbc_class) list;
    char name[80];
    char dsn[80];
    char *username;
    char *password;
    char *sanitysql;
    SQLHENV env;
    unsigned int delme:1;                /*!< Purge the class */
    unsigned int backslash_is_escape:1;  /*!< On this database, the backslash is a native escape sequence */
    unsigned int forcecommit:1;          /*!< Should uncommitted transactions be auto-committed on handle release? */
    unsigned int cache_is_queue:1;       /*!< Connection cache should be a queue (round-robin use) rather than a stack (last release, first re-use) */
    unsigned int isolation;              /*!< Flags for how the DB should deal with data in other, uncommitted transactions */
    unsigned int conntimeout;            /*!< Maximum time the connection process should take */
    unsigned int maxconnections;         /*!< Maximum number of allowed connections */
    /*! When a connection fails, cache that failure for how long? */
    struct timeval negative_connection_cache;
    /*! When a connection fails, when did that last occur? */
    struct timeval last_negative_connect;
    /*! A pool of available connections */
    AST_LIST_HEAD_NOLOCK(, odbc_obj) connections;
    /*! Lock to protect the connections */
    ast_mutex_t lock;
    /*! Condition to notify any pending connection requesters */
    ast_cond_t cond;
    /*! The total number of current connections */
    size_t connection_cnt;
    /*! Whether logging is enabled on this class or not */
    unsigned int logging;
    /*! The number of prepares executed on this class (total from all connections */
    int prepares_executed;
    /*! The number of queries executed on this class (total from all connections) */
    int queries_executed;
    /*! The longest execution time for a query executed on this class */
    long longest_query_execution_time;
    /*! The SQL query that took the longest to execute */
    char *sql_text;
    /*! Slow query limit (in milliseconds) */
    unsigned int slowquerylimit;
    /*! Maximum number of cached connections, default is maxconnections */
    unsigned int max_cache_size;
    /*! Current cached connection count, when cache_size will exceed max_cache_size, longest-idle connection will be dropped from the cache */
    unsigned int cur_cache;
};
 
static struct ao2_container *class_container;
 
static AST_RWLIST_HEAD_STATIC(odbc_tables, odbc_cache_tables);
 
static odbc_status odbc_obj_connect(struct odbc_obj *obj);
static odbc_status odbc_obj_disconnect(struct odbc_obj *obj);
static void odbc_register_class(struct odbc_class *class, int connect);
 
AST_THREADSTORAGE(errors_buf);
 
struct odbc_txn_frame {
    AST_LIST_ENTRY(odbc_txn_frame) list;
    struct ast_channel *owner;
    struct odbc_obj *obj;        /*!< Database handle within which transacted statements are run */
    /*!\brief Is this record the current active transaction within the channel?
     * Note that the active flag is really only necessary for statements which
     * are triggered from the dialplan, as there isn't a direct correlation
     * between multiple statements.  Applications wishing to use transactions
     * may simply perform each statement on the same odbc_obj, which keeps the
     * transaction persistent.
     */
    unsigned int active:1;
    unsigned int forcecommit:1;     /*!< Should uncommitted transactions be auto-committed on handle release? */
    unsigned int isolation;         /*!< Flags for how the DB should deal with data in other, uncommitted transactions */
    char name[0];                   /*!< Name of this transaction ID */
};
 
const char *ast_odbc_isolation2text(int iso)
{
    if (iso == SQL_TXN_READ_COMMITTED) {
        return "read_committed";
    } else if (iso == SQL_TXN_READ_UNCOMMITTED) {
        return "read_uncommitted";
    } else if (iso == SQL_TXN_SERIALIZABLE) {
        return "serializable";
    } else if (iso == SQL_TXN_REPEATABLE_READ) {
        return "repeatable_read";
    } else {
        return "unknown";
    }
}
 
int ast_odbc_text2isolation(const char *txt)
{
    if (strncasecmp(txt, "read_", 5) == 0) {
        if (strncasecmp(txt + 5, "c", 1) == 0) {
            return SQL_TXN_READ_COMMITTED;
        } else if (strncasecmp(txt + 5, "u", 1) == 0) {
            return SQL_TXN_READ_UNCOMMITTED;
        } else {
            return 0;
        }
    } else if (strncasecmp(txt, "ser", 3) == 0) {
        return SQL_TXN_SERIALIZABLE;
    } else if (strncasecmp(txt, "rep", 3) == 0) {
        return SQL_TXN_REPEATABLE_READ;
    } else {
        return 0;
    }
}
 
static void odbc_class_destructor(void *data)
{
    struct odbc_class *class = data;
    struct odbc_obj *obj;
 
    /* Due to refcounts, we can safely assume that any objects with a reference
     * to us will prevent our destruction, so we don't need to worry about them.
     */
    if (class->username) {
        ast_free(class->username);
    }
    if (class->password) {
        ast_free(class->password);
    }
    if (class->sanitysql) {
        ast_free(class->sanitysql);
    }
 
    while ((obj = AST_LIST_REMOVE_HEAD(&class->connections, list))) {
        ao2_ref(obj, -1);
    }
 
    SQLFreeHandle(SQL_HANDLE_ENV, class->env);
    ast_mutex_destroy(&class->lock);
    ast_cond_destroy(&class->cond);
    ast_free(class->sql_text);
}
 
static void odbc_obj_destructor(void *data)
{
    struct odbc_obj *obj = data;
 
    odbc_obj_disconnect(obj);
}
 
static void destroy_table_cache(struct odbc_cache_tables *table)
{
    struct odbc_cache_columns *col;
 
    ast_debug(1, "Destroying table cache for %s\n", table->table);
 
    AST_RWLIST_WRLOCK(&table->columns);
    while ((col = AST_RWLIST_REMOVE_HEAD(&table->columns, list))) {
        ast_free(col);
    }
    AST_RWLIST_UNLOCK(&table->columns);
    AST_RWLIST_HEAD_DESTROY(&table->columns);
 
    ast_free(table);
}
 
/*!
 * XXX This creates a connection and disconnects it. In some situations, the caller of
 * this function has its own connection and could donate it to this function instead of
 * needing to create another one.
 *
 * XXX The automatic readlock of the columns is awkward. It's done because it's possible for
 * multiple threads to have references to the table, and the table is not refcounted. Possible
 * changes here would be
 * * Eliminate the table cache entirely. The use of ast_odbc_find_table() is generally
 *   questionable. The only real good use right now is from ast_realtime_require_field() in
 *   order to make sure the DB has the expected columns in it. Since that is only used sparingly,
 *   the need to cache tables is questionable. Instead, the table structure can be fetched from
 *   the DB directly each time, resulting in a single owner of the data.
 * * Make odbc_cache_tables a refcounted object.
 */
struct odbc_cache_tables *ast_odbc_find_table(const char *database, const char *tablename)
{
    struct odbc_cache_tables *tableptr;
    struct odbc_cache_columns *entry;
    char columnname[80];
    SQLLEN sqlptr;
    SQLHSTMT stmt = NULL;
    int res = 0, error = 0;
    struct odbc_obj *obj;
 
    AST_RWLIST_RDLOCK(&odbc_tables);
    AST_RWLIST_TRAVERSE(&odbc_tables, tableptr, list) {
        if (strcmp(tableptr->connection, database) == 0 && strcmp(tableptr->table, tablename) == 0) {
            break;
        }
    }
    if (tableptr) {
        AST_RWLIST_RDLOCK(&tableptr->columns);
        AST_RWLIST_UNLOCK(&odbc_tables);
        return tableptr;
    }
 
    if (!(obj = ast_odbc_request_obj(database, 0))) {
        ast_log(LOG_WARNING, "Unable to retrieve database handle for table description '%s@%s'\n", tablename, database);
        AST_RWLIST_UNLOCK(&odbc_tables);
        return NULL;
    }
 
    /* Table structure not already cached; build it now. */
    do {
        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 on connection '%s'!\n", database);
            break;
        }
 
        res = SQLColumns(stmt, NULL, 0, NULL, 0, (unsigned char *)tablename, SQL_NTS, (unsigned char *)"%", SQL_NTS);
        if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
            SQLFreeHandle(SQL_HANDLE_STMT, stmt);
            ast_log(LOG_ERROR, "Unable to query database columns on connection '%s'.\n", database);
            break;
        }
 
        if (!(tableptr = ast_calloc(sizeof(char), sizeof(*tableptr) + strlen(database) + 1 + strlen(tablename) + 1))) {
            ast_log(LOG_ERROR, "Out of memory creating entry for table '%s' on connection '%s'\n", tablename, database);
            break;
        }
 
        tableptr->connection = (char *)tableptr + sizeof(*tableptr);
        tableptr->table = (char *)tableptr + sizeof(*tableptr) + strlen(database) + 1;
        strcpy(tableptr->connection, database); /* SAFE */
        strcpy(tableptr->table, tablename); /* SAFE */
        AST_RWLIST_HEAD_INIT(&(tableptr->columns));
 
        while ((res = SQLFetch(stmt)) != SQL_NO_DATA && res != SQL_ERROR) {
            SQLGetData(stmt,  4, SQL_C_CHAR, columnname, sizeof(columnname), &sqlptr);
 
            if (!(entry = ast_calloc(sizeof(char), sizeof(*entry) + strlen(columnname) + 1))) {
                ast_log(LOG_ERROR, "Out of memory creating entry for column '%s' in table '%s' on connection '%s'\n", columnname, tablename, database);
                error = 1;
                break;
            }
            entry->name = (char *)entry + sizeof(*entry);
            strcpy(entry->name, columnname);
 
            SQLGetData(stmt,  5, SQL_C_SHORT, &entry->type, sizeof(entry->type), NULL);
            SQLGetData(stmt,  7, SQL_C_LONG, &entry->size, sizeof(entry->size), NULL);
            SQLGetData(stmt,  9, SQL_C_SHORT, &entry->decimals, sizeof(entry->decimals), NULL);
            SQLGetData(stmt, 10, SQL_C_SHORT, &entry->radix, sizeof(entry->radix), NULL);
            SQLGetData(stmt, 11, SQL_C_SHORT, &entry->nullable, sizeof(entry->nullable), NULL);
            SQLGetData(stmt, 16, SQL_C_LONG, &entry->octetlen, sizeof(entry->octetlen), NULL);
 
            /* Specification states that the octenlen should be the maximum number of bytes
             * returned in a char or binary column, but it seems that some drivers just set
             * it to NULL. (Bad Postgres! No biscuit!) */
            if (entry->octetlen == 0) {
                entry->octetlen = entry->size;
            }
 
            ast_debug(3, "Found %s column with type %hd with len %ld, octetlen %ld, and numlen (%hd,%hd)\n", entry->name, entry->type, (long) entry->size, (long) entry->octetlen, entry->decimals, entry->radix);
            /* Insert column info into column list */
            AST_LIST_INSERT_TAIL(&(tableptr->columns), entry, list);
        }
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
 
        AST_RWLIST_INSERT_TAIL(&odbc_tables, tableptr, list);
        AST_RWLIST_RDLOCK(&(tableptr->columns));
        break;
    } while (1);
 
    AST_RWLIST_UNLOCK(&odbc_tables);
 
    if (error) {
        destroy_table_cache(tableptr);
        tableptr = NULL;
    }
    ast_odbc_release_obj(obj);
    return tableptr;
}
 
struct odbc_cache_columns *ast_odbc_find_column(struct odbc_cache_tables *table, const char *colname)
{
    struct odbc_cache_columns *col;
    AST_RWLIST_TRAVERSE(&table->columns, col, list) {
        if (strcasecmp(col->name, colname) == 0) {
            return col;
        }
    }
    return NULL;
}
 
int ast_odbc_clear_cache(const char *database, const char *tablename)
{
    struct odbc_cache_tables *tableptr;
 
    AST_RWLIST_WRLOCK(&odbc_tables);
    AST_RWLIST_TRAVERSE_SAFE_BEGIN(&odbc_tables, tableptr, list) {
        if (strcmp(tableptr->connection, database) == 0 && strcmp(tableptr->table, tablename) == 0) {
            AST_LIST_REMOVE_CURRENT(list);
            destroy_table_cache(tableptr);
            break;
        }
    }
    AST_RWLIST_TRAVERSE_SAFE_END
    AST_RWLIST_UNLOCK(&odbc_tables);
    return tableptr ? 0 : -1;
}
 
SQLHSTMT ast_odbc_direct_execute(struct odbc_obj *obj, SQLHSTMT (*exec_cb)(struct odbc_obj *obj, void *data), void *data)
{
    struct timeval start;
    SQLHSTMT stmt;
 
    if (obj->parent->logging) {
        start = ast_tvnow();
    }
 
    stmt = exec_cb(obj, data);
 
    if (obj->parent->logging) {
        long execution_time = ast_tvdiff_ms(ast_tvnow(), start);
 
        if (obj->parent->slowquerylimit && execution_time > obj->parent->slowquerylimit) {
            ast_log(LOG_WARNING, "SQL query '%s' took %ld milliseconds to execute on class '%s', this may indicate a database problem\n",
                obj->sql_text, execution_time, obj->parent->name);
        }
 
        ast_mutex_lock(&obj->parent->lock);
        if (execution_time > obj->parent->longest_query_execution_time || !obj->parent->sql_text) {
            obj->parent->longest_query_execution_time = execution_time;
            /* Due to the callback nature of the res_odbc API it's not possible to ensure that
             * the SQL text is removed from the connection in all cases, so only if it becomes the
             * new longest executing query do we steal the SQL text. In other cases what will happen
             * is that the SQL text will be freed if the connection is released back to the class or
             * if a new query is done on the connection.
             */
            ast_free(obj->parent->sql_text);
            obj->parent->sql_text = obj->sql_text;
            obj->sql_text = NULL;
        }
        ast_mutex_unlock(&obj->parent->lock);
    }
 
    return stmt;
}
 
SQLHSTMT ast_odbc_prepare_and_execute(struct odbc_obj *obj, SQLHSTMT (*prepare_cb)(struct odbc_obj *obj, void *data), void *data)
{
    struct timeval start;
    int res = 0;
    SQLHSTMT stmt;
 
    if (obj->parent->logging) {
        start = ast_tvnow();
    }
 
    /* This prepare callback may do more than just prepare -- it may also
     * bind parameters, bind results, etc.  The real key, here, is that
     * when we disconnect, all handles become invalid for most databases.
     * We must therefore redo everything when we establish a new
     * connection. */
    stmt = prepare_cb(obj, data);
    if (!stmt) {
        return NULL;
    }
 
    res = SQLExecute(stmt);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
        if (res == SQL_ERROR) {
            ast_odbc_print_errors(SQL_HANDLE_STMT, stmt, "SQL Execute");
        }
 
        ast_log(LOG_WARNING, "SQL Execute error %d!\n", res);
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
        stmt = NULL;
    } else if (obj->parent->logging) {
        long execution_time = ast_tvdiff_ms(ast_tvnow(), start);
 
        if (obj->parent->slowquerylimit && execution_time > obj->parent->slowquerylimit) {
            ast_log(LOG_WARNING, "SQL query '%s' took %ld milliseconds to execute on class '%s', this may indicate a database problem\n",
                obj->sql_text, execution_time, obj->parent->name);
        }
 
        ast_mutex_lock(&obj->parent->lock);
 
        /* If this takes the record on longest query execution time, update the parent class
         * with the information.
         */
        if (execution_time > obj->parent->longest_query_execution_time || !obj->parent->sql_text) {
            obj->parent->longest_query_execution_time = execution_time;
            ast_free(obj->parent->sql_text);
            obj->parent->sql_text = obj->sql_text;
            obj->sql_text = NULL;
        }
        ast_mutex_unlock(&obj->parent->lock);
 
        ast_atomic_fetchadd_int(&obj->parent->queries_executed, +1);
    }
 
    return stmt;
}
 
int ast_odbc_prepare(struct odbc_obj *obj, SQLHSTMT *stmt, const char *sql)
{
    if (obj->parent->logging) {
        /* It is possible for this connection to be reused without being
         * released back to the class, so we free what may already exist
         * and place the new SQL in.
         */
        ast_free(obj->sql_text);
        obj->sql_text = ast_strdup(sql);
        ast_atomic_fetchadd_int(&obj->parent->prepares_executed, +1);
    }
 
    return SQLPrepare(stmt, (unsigned char *)sql, SQL_NTS);
}
 
SQLRETURN ast_odbc_execute_sql(struct odbc_obj *obj, SQLHSTMT *stmt, const char *sql)
{
    if (obj->parent->logging) {
        ast_free(obj->sql_text);
        obj->sql_text = ast_strdup(sql);
        ast_atomic_fetchadd_int(&obj->parent->queries_executed, +1);
    }
 
    return SQLExecDirect(stmt, (unsigned char *)sql, SQL_NTS);
}
 
int ast_odbc_smart_execute(struct odbc_obj *obj, SQLHSTMT stmt)
{
    int res = 0;
 
    res = SQLExecute(stmt);
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
        if (res == SQL_ERROR) {
            ast_odbc_print_errors(SQL_HANDLE_STMT, stmt, "SQL Execute");
        }
    }
 
    if (obj->parent->logging) {
        ast_atomic_fetchadd_int(&obj->parent->queries_executed, +1);
    }
 
    return res;
}
 
SQLRETURN ast_odbc_ast_str_SQLGetData(struct ast_str **buf, int pmaxlen, SQLHSTMT StatementHandle, SQLUSMALLINT ColumnNumber, SQLSMALLINT TargetType, SQLLEN *StrLen_or_Ind)
{
    SQLRETURN res;
 
    if (pmaxlen == 0) {
        if (SQLGetData(StatementHandle, ColumnNumber, TargetType, ast_str_buffer(*buf), 0, StrLen_or_Ind) == SQL_SUCCESS_WITH_INFO) {
            ast_str_make_space(buf, *StrLen_or_Ind + 1);
        }
    } else if (pmaxlen > 0) {
        ast_str_make_space(buf, pmaxlen);
    }
    res = SQLGetData(StatementHandle, ColumnNumber, TargetType, ast_str_buffer(*buf), ast_str_size(*buf), StrLen_or_Ind);
    ast_str_update(*buf);
 
    return res;
}
 
struct ast_str *ast_odbc_print_errors(SQLSMALLINT handle_type, SQLHANDLE handle, const char *operation)
{
    struct ast_str *errors = ast_str_thread_get(&errors_buf, 16);
    SQLINTEGER nativeerror = 0;
    SQLSMALLINT diagbytes = 0;
    SQLSMALLINT i;
    unsigned char state[10];
    unsigned char diagnostic[256];
 
    ast_str_reset(errors);
    i = 0;
    while (SQLGetDiagRec(handle_type, handle, ++i, state, &nativeerror,
        diagnostic, sizeof(diagnostic), &diagbytes) == SQL_SUCCESS) {
        ast_str_append(&errors, 0, "%s%s", ast_str_strlen(errors) ? "," : "", state);
        ast_log(LOG_WARNING, "%s returned an error: %s: %s\n", operation, state, diagnostic);
        /* XXX Why is this here? */
        if (i > 10) {
            ast_log(LOG_WARNING, "There are more than 10 diagnostic records! Ignore the rest.\n");
            break;
        }
    }
 
    return errors;
}
 
unsigned int ast_odbc_class_get_isolation(struct odbc_class *class)
{
    return class->isolation;
}
 
unsigned int ast_odbc_class_get_forcecommit(struct odbc_class *class)
{
    return class->forcecommit;
}
 
const char *ast_odbc_class_get_name(struct odbc_class *class)
{
    return class->name;
}
 
static int load_odbc_config(void)
{
    static char *cfg = "res_odbc.conf";
    struct ast_config *config;
    struct ast_variable *v;
    char *cat;
    const char *dsn, *username, *password, *sanitysql;
    int enabled, bse, conntimeout, forcecommit, isolation, maxconnections, logging, slowquerylimit;
    struct timeval ncache = { 0, 0 };
    int preconnect = 0, res = 0, cache_is_queue = 0;
    struct ast_flags config_flags = { 0 };
    unsigned int max_cache_size;
 
    struct odbc_class *new;
 
    config = ast_config_load(cfg, config_flags);
    if (config == CONFIG_STATUS_FILEMISSING || config == CONFIG_STATUS_FILEINVALID) {
        ast_log(LOG_WARNING, "Unable to load config file res_odbc.conf\n");
        return -1;
    }
    for (cat = ast_category_browse(config, NULL); cat; cat=ast_category_browse(config, cat)) {
        if (!strcasecmp(cat, "ENV")) {
            for (v = ast_variable_browse(config, cat); v; v = v->next) {
                setenv(v->name, v->value, 1);
                ast_log(LOG_NOTICE, "Adding ENV var: %s=%s\n", v->name, v->value);
            }
        } else {
            /* Reset all to defaults for each class of odbc connections */
            dsn = username = password = sanitysql = NULL;
            enabled = 1;
            preconnect = 0;
            bse = 1;
            conntimeout = 10;
            forcecommit = 0;
            isolation = SQL_TXN_READ_COMMITTED;
            maxconnections = 1;
            logging = 0;
            slowquerylimit = 5000;
            cache_is_queue = 0;
            max_cache_size = UINT_MAX;
            for (v = ast_variable_browse(config, cat); v; v = v->next) {
                if (!strcasecmp(v->name, "pooling") ||
                        !strncasecmp(v->name, "share", 5) ||
                        !strcasecmp(v->name, "limit") ||
                        !strcasecmp(v->name, "idlecheck")) {
                    ast_log(LOG_WARNING, "The 'pooling', 'shared_connections', 'limit', and 'idlecheck' options were replaced by 'max_connections'.  See res_odbc.conf.sample.\n");
                } else if (!strcasecmp(v->name, "enabled")) {
                    enabled = ast_true(v->value);
                } else if (!strcasecmp(v->name, "pre-connect")) {
                    preconnect = ast_true(v->value);
                } else if (!strcasecmp(v->name, "dsn")) {
                    dsn = v->value;
                } else if (!strcasecmp(v->name, "username")) {
                    username = v->value;
                } else if (!strcasecmp(v->name, "password")) {
                    password = v->value;
                } else if (!strcasecmp(v->name, "sanitysql")) {
                    sanitysql = v->value;
                } else if (!strcasecmp(v->name, "backslash_is_escape")) {
                    bse = ast_true(v->value);
                } else if (!strcasecmp(v->name, "connect_timeout")) {
                    if (sscanf(v->value, "%d", &conntimeout) != 1 || conntimeout < 1) {
                        ast_log(LOG_WARNING, "connect_timeout must be a positive integer\n");
                        conntimeout = 10;
                    }
                } else if (!strcasecmp(v->name, "negative_connection_cache")) {
                    double dncache;
                    if (sscanf(v->value, "%lf", &dncache) != 1 || dncache < 0) {
                        ast_log(LOG_WARNING, "negative_connection_cache must be a non-negative integer\n");
                        /* 5 minutes sounds like a reasonable default */
                        ncache.tv_sec = 300;
                        ncache.tv_usec = 0;
                    } else {
                        ncache.tv_sec = (int)dncache;
                        ncache.tv_usec = (dncache - ncache.tv_sec) * 1000000;
                    }
                } else if (!strcasecmp(v->name, "forcecommit")) {
                    forcecommit = ast_true(v->value);
                } else if (!strcasecmp(v->name, "isolation")) {
                    if ((isolation = ast_odbc_text2isolation(v->value)) == 0) {
                        ast_log(LOG_ERROR, "Unrecognized value for 'isolation': '%s' in section '%s'\n", v->value, cat);
                        isolation = SQL_TXN_READ_COMMITTED;
                    }
                } else if (!strcasecmp(v->name, "max_connections")) {
                    if (sscanf(v->value, "%30d", &maxconnections) != 1 || maxconnections < 1) {
                        ast_log(LOG_WARNING, "max_connections must be a positive integer\n");
                        maxconnections = 1;
                                        }
                } else if (!strcasecmp(v->name, "logging")) {
                    logging = ast_true(v->value);
                } else if (!strcasecmp(v->name, "slow_query_limit")) {
                    if (sscanf(v->value, "%30d", &slowquerylimit) != 1) {
                        ast_log(LOG_WARNING, "slow_query_limit must be a positive integer\n");
                        slowquerylimit = 5000;
                    }
                } else if (!strcasecmp(v->name, "cache_type")) {
                    cache_is_queue = !strcasecmp(v->value, "rr") ||
                        !strcasecmp(v->value, "roundrobin") ||
                        !strcasecmp(v->value, "queue");
                } else if (!strcasecmp(v->name, "cache_size")) {
                    if (!strcasecmp(v->value, "-1")) {
                        max_cache_size = UINT_MAX;
                    } else if (sscanf(v->value, "%u", &max_cache_size) != 1) {
                        ast_log(LOG_WARNING, "cache_size must be a non-negative integer or -1 (infinite)\n");
                    }
                }
            }
 
            if (enabled && !ast_strlen_zero(dsn)) {
                new = ao2_alloc(sizeof(*new), odbc_class_destructor);
 
                if (!new) {
                    res = -1;
                    break;
                }
 
                SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &new->env);
                res = SQLSetEnvAttr(new->env, SQL_ATTR_ODBC_VERSION, (void *) SQL_OV_ODBC3, 0);
 
                if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
                    ast_log(LOG_WARNING, "res_odbc: Error SetEnv\n");
                    ao2_ref(new, -1);
                    return res;
                }
 
                new->backslash_is_escape = bse ? 1 : 0;
                new->forcecommit = forcecommit ? 1 : 0;
                new->isolation = isolation;
                new->conntimeout = conntimeout;
                new->negative_connection_cache = ncache;
                new->maxconnections = maxconnections;
                new->logging = logging;
                new->slowquerylimit = slowquerylimit;
                new->cache_is_queue = cache_is_queue;
                new->max_cache_size = max_cache_size;
                new->cur_cache = 0;
 
                if (cat)
                    ast_copy_string(new->name, cat, sizeof(new->name));
                if (dsn)
                    ast_copy_string(new->dsn, dsn, sizeof(new->dsn));
                if (username && !(new->username = ast_strdup(username))) {
                    ao2_ref(new, -1);
                    break;
                }
                if (password && !(new->password = ast_strdup(password))) {
                    ao2_ref(new, -1);
                    break;
                }
                if (sanitysql && !(new->sanitysql = ast_strdup(sanitysql))) {
                    ao2_ref(new, -1);
                    break;
                }
 
                ast_mutex_init(&new->lock);
                ast_cond_init(&new->cond, NULL);
 
                odbc_register_class(new, preconnect);
                ast_log(LOG_NOTICE, "Registered ODBC class '%s' dsn->[%s]\n", cat, dsn);
                ao2_ref(new, -1);
                new = NULL;
            }
        }
    }
    ast_config_destroy(config);
    return res;
}
 
static char *handle_cli_odbc_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
    struct ao2_iterator aoi;
    struct odbc_class *class;
    int length = 0;
    int which = 0;
    char *ret = NULL;
 
    switch (cmd) {
    case CLI_INIT:
        e->command = "odbc show";
        e->usage =
                "Usage: odbc show [class]\n"
                "       List settings of a particular ODBC class or,\n"
                "       if not specified, all classes.\n";
        return NULL;
    case CLI_GENERATE:
        if (a->pos != 2)
            return NULL;
        length = strlen(a->word);
        aoi = ao2_iterator_init(class_container, 0);
        while ((class = ao2_iterator_next(&aoi))) {
            if (!strncasecmp(a->word, class->name, length) && ++which > a->n) {
                ret = ast_strdup(class->name);
            }
            ao2_ref(class, -1);
            if (ret) {
                break;
            }
        }
        ao2_iterator_destroy(&aoi);
        if (!ret && !strncasecmp(a->word, "all", length) && ++which > a->n) {
            ret = ast_strdup("all");
        }
        return ret;
    }
 
    ast_cli(a->fd, "\nODBC DSN Settings\n");
    ast_cli(a->fd,   "-----------------\n\n");
    aoi = ao2_iterator_init(class_container, 0);
    while ((class = ao2_iterator_next(&aoi))) {
        if ((a->argc == 2) || (a->argc == 3 && !strcmp(a->argv[2], "all")) || (!strcmp(a->argv[2], class->name))) {
            char timestr[80];
            struct ast_tm tm;
 
            ast_cli(a->fd, "  Name:   %s\n  DSN:    %s\n", class->name, class->dsn);
 
            if (class->last_negative_connect.tv_sec > 0) {
                ast_localtime(&class->last_negative_connect, &tm, NULL);
                ast_strftime(timestr, sizeof(timestr), "%Y-%m-%d %T", &tm);
                ast_cli(a->fd, "    Last fail connection attempt: %s\n", timestr);
            }
 
            ast_cli(a->fd, "    Number of active connections: %zd (out of %d)\n", class->connection_cnt, class->maxconnections);
            ast_cli(a->fd, "    Cache Type: %s\n", class->cache_is_queue ? "round-robin queue" : "stack (last release, first re-use)");
            ast_cli(a->fd, "    Cache Usage: %u cached out of %u\n", class->cur_cache,
                    class->max_cache_size < class->maxconnections ? class->max_cache_size : class->maxconnections);
            ast_cli(a->fd, "    Logging: %s\n", class->logging ? "Enabled" : "Disabled");
            if (class->logging) {
                ast_cli(a->fd, "    Number of prepares executed: %d\n", class->prepares_executed);
                ast_cli(a->fd, "    Number of queries executed: %d\n", class->queries_executed);
                ast_mutex_lock(&class->lock);
                if (class->sql_text) {
                    ast_cli(a->fd, "    Longest running SQL query: %s (%ld milliseconds)\n", class->sql_text, class->longest_query_execution_time);
                }
                ast_mutex_unlock(&class->lock);
            }
            ast_cli(a->fd, "\n");
        }
        ao2_ref(class, -1);
    }
    ao2_iterator_destroy(&aoi);
 
    return CLI_SUCCESS;
}
 
static struct ast_cli_entry cli_odbc[] = {
    AST_CLI_DEFINE(handle_cli_odbc_show, "List ODBC DSN(s)")
};
 
static void odbc_register_class(struct odbc_class *class, int preconnect)
{
    struct odbc_obj *obj;
 
    ao2_link(class_container, class);
    /* I still have a reference in the caller, so a deref is NOT missing here. */
 
    if (!preconnect) {
        return;
    }
 
    /* Request and release builds a connection */
    obj = ast_odbc_request_obj(class->name, 0);
    if (obj) {
        ast_odbc_release_obj(obj);
    }
 
    return;
}
 
void ast_odbc_release_obj(struct odbc_obj *obj)
{
    struct odbc_class *class = obj->parent;
 
    ast_debug(2, "Releasing ODBC handle %p into pool\n", obj);
 
    /* The odbc_obj only holds a reference to the class when it is
     * actively being used. This guarantees no circular reference
     * between odbc_class and odbc_obj. Since it is being released
     * we also release our class reference. If a reload occurred before
     * the class will go away automatically once all odbc_obj are
     * released back.
     */
    obj->parent = NULL;
 
    /* Free the SQL text so that the next user of this connection has
     * a fresh start.
     */
    ast_free(obj->sql_text);
    obj->sql_text = NULL;
 
    ast_mutex_lock(&class->lock);
    if (class->cache_is_queue) {
        AST_LIST_INSERT_TAIL(&class->connections, obj, list);
    } else {
        AST_LIST_INSERT_HEAD(&class->connections, obj, list);
    }
 
    if (class->cur_cache >= class->max_cache_size) {
        /* cache is full */
        if (class->cache_is_queue) {
            /* HEAD will be oldest */
            obj = AST_LIST_REMOVE_HEAD(&class->connections, list);
        } else {
            /* TAIL will be oldest */
            obj = AST_LIST_LAST(&class->connections);
            AST_LIST_REMOVE(&class->connections, obj, list);
        }
        --class->connection_cnt;
        ast_mutex_unlock(&class->lock);
 
        ast_debug(2, "ODBC Pool '%s' exceeded cache size, dropping '%p', connection count is %zd (%u cached)\n",
            class->name, obj, class->connection_cnt, class->cur_cache);
 
        ao2_ref(obj, -1);
 
        ast_mutex_lock(&class->lock);
    } else {
        ++class->cur_cache;
    }
    ast_cond_signal(&class->cond);
    ast_mutex_unlock(&class->lock);
 
    ao2_ref(class, -1);
}
 
int ast_odbc_backslash_is_escape(struct odbc_obj *obj)
{
    return obj->parent->backslash_is_escape;
}
 
static int aoro2_class_cb(void *obj, void *arg, int flags)
{
    struct odbc_class *class = obj;
    char *name = arg;
    if (!strcmp(class->name, name) && !class->delme) {
        return CMP_MATCH | CMP_STOP;
    }
    return 0;
}
 
unsigned int ast_odbc_get_max_connections(const char *name)
{
    struct odbc_class *class;
    unsigned int max_connections;
 
    class = ao2_callback(class_container, 0, aoro2_class_cb, (char *) name);
    if (!class) {
        return 0;
    }
 
    max_connections = class->maxconnections;
    ao2_ref(class, -1);
 
    return max_connections;
}
 
/*!
 * \brief Determine if the connection has died.
 *
 * \param connection The connection to check
 * \param class The ODBC class
 * \retval 1 Yep, it's dead
 * \retval 0 It's alive and well
 */
static int connection_dead(struct odbc_obj *connection, struct odbc_class *class)
{
    char *test_sql = "select 1";
    SQLINTEGER dead;
    SQLRETURN res;
    SQLHSTMT stmt;
 
    res = SQLGetConnectAttr(connection->con, SQL_ATTR_CONNECTION_DEAD, &dead, 0, 0);
    if (SQL_SUCCEEDED(res)) {
        return dead == SQL_CD_TRUE ? 1 : 0;
    }
 
    /* If the Driver doesn't support SQL_ATTR_CONNECTION_DEAD do a
     * probing query instead
     */
    res = SQLAllocHandle(SQL_HANDLE_STMT, connection->con, &stmt);
    if (!SQL_SUCCEEDED(res)) {
        return 1;
    }
 
    if (!ast_strlen_zero(class->sanitysql)) {
        test_sql = class->sanitysql;
    }
 
    res = SQLPrepare(stmt, (unsigned char *)test_sql, SQL_NTS);
    if (!SQL_SUCCEEDED(res)) {
        SQLFreeHandle(SQL_HANDLE_STMT, stmt);
        return 1;
    }
 
    res = SQLExecute(stmt);
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
 
    return SQL_SUCCEEDED(res) ? 0 : 1;
}
 
struct odbc_obj *_ast_odbc_request_obj2(const char *name, struct ast_flags flags, const char *file, const char *function, int lineno)
{
    struct odbc_obj *obj = NULL;
    struct odbc_class *class;
 
    if (!(class = ao2_callback(class_container, 0, aoro2_class_cb, (char *) name))) {
        ast_debug(1, "Class '%s' not found!\n", name);
        return NULL;
    }
 
    while (!obj) {
        ast_mutex_lock(&class->lock);
 
        obj = AST_LIST_REMOVE_HEAD(&class->connections, list);
        if (obj) {
            --class->cur_cache;
        }
 
        ast_mutex_unlock(&class->lock);
 
        if (!obj) {
            ast_mutex_lock(&class->lock);
 
            if (class->connection_cnt < class->maxconnections) {
                /* If no connection is immediately available establish a new
                 * one if allowed. If we try and fail we give up completely as
                 * we could go into an infinite loop otherwise.
                 */
                obj = ao2_alloc(sizeof(*obj), odbc_obj_destructor);
                if (!obj) {
                    ast_mutex_unlock(&class->lock);
                    break;
                }
 
                obj->parent = ao2_bump(class);
 
                class->connection_cnt++;
 
                ast_mutex_unlock(&class->lock);
 
                if (odbc_obj_connect(obj) == ODBC_FAIL) {
                    ast_mutex_lock(&class->lock);
                    class->connection_cnt--;
                    ast_cond_signal(&class->cond);
                    ast_mutex_unlock(&class->lock);
                    ao2_ref(obj->parent, -1);
                    ao2_ref(obj, -1);
                    obj = NULL;
                    break;
                }
 
                ast_mutex_lock(&class->lock);
 
                ast_debug(2, "Created ODBC handle %p on class '%s', new count is %zd\n", obj,
                    name, class->connection_cnt);
 
            } else {
                /* Otherwise if we're not allowed to create a new one we
                 * wait for another thread to give up the connection they
                 * own.
                 */
                ast_cond_wait(&class->cond, &class->lock);
            }
 
            ast_mutex_unlock(&class->lock);
 
        } else if (connection_dead(obj, class)) {
            /* If the connection is dead try to grab another functional one from the
             * pool instead of trying to resurrect this one.
             */
            ast_mutex_lock(&class->lock);
 
            class->connection_cnt--;
            /* this thread will re-acquire, and if that fails will signal,
             * thus no need to signal class->cond here */
            ast_debug(2, "ODBC handle %p dead - removing from class '%s', new count is %zd\n",
                obj, name, class->connection_cnt);
 
            ast_mutex_unlock(&class->lock);
 
            ao2_ref(obj, -1);
            obj = NULL;
        } else {
            /* We successfully grabbed a connection from the pool and all is well!
             */
            obj->parent = ao2_bump(class);
            ast_debug(2, "Reusing ODBC handle %p from class '%s'\n", obj, name);
        }
    }
 
    ao2_ref(class, -1);
 
    return obj;
}
 
struct odbc_obj *_ast_odbc_request_obj(const char *name, int check, const char *file, const char *function, int lineno)
{
    struct ast_flags flags = { check ? RES_ODBC_SANITY_CHECK : 0 };
    /* XXX New flow means that the "check" parameter doesn't do anything. We're requesting
     * a connection from ODBC. We'll either get a new one, which obviously is already connected, or
     * we'll get one from the ODBC connection pool. In that case, it will ensure to only give us a
     * live connection
     */
    return _ast_odbc_request_obj2(name, flags, file, function, lineno);
}
 
static odbc_status odbc_obj_disconnect(struct odbc_obj *obj)
{
    int res;
    SQLINTEGER err;
    short int mlen;
    unsigned char msg[200], state[10];
    SQLHDBC con;
 
    /* Nothing to disconnect */
    if (!obj->con) {
        return ODBC_SUCCESS;
    }
 
    con = obj->con;
    obj->con = NULL;
    res = SQLDisconnect(con);
 
    if ((res = SQLFreeHandle(SQL_HANDLE_DBC, con)) == SQL_SUCCESS) {
        ast_debug(3, "Database handle %p (connection %p) deallocated\n", obj, con);
    } else {
        SQLGetDiagRec(SQL_HANDLE_DBC, con, 1, state, &err, msg, 100, &mlen);
        ast_log(LOG_WARNING, "Unable to deallocate database handle %p? %d errno=%d %s\n", con, res, (int)err, msg);
    }
 
    return ODBC_SUCCESS;
}
 
static odbc_status odbc_obj_connect(struct odbc_obj *obj)
{
    int res;
    SQLINTEGER err;
    short int mlen;
    unsigned char msg[200], state[10];
#ifdef NEEDTRACE
    SQLINTEGER enable = 1;
    char *tracefile = "/tmp/odbc.trace";
#endif
    SQLHDBC con;
    long int negative_cache_expiration;
 
    ast_assert(obj->con == NULL);
    ast_debug(3, "Connecting %s(%p)\n", obj->parent->name, obj);
 
    /* Dont connect while server is marked as unreachable via negative_connection_cache */
    negative_cache_expiration = obj->parent->last_negative_connect.tv_sec + obj->parent->negative_connection_cache.tv_sec;
    if (time(NULL) < negative_cache_expiration) {
        char secs[AST_TIME_T_LEN];
        ast_time_t_to_string(negative_cache_expiration - time(NULL), secs, sizeof(secs));
        ast_log(LOG_WARNING, "Not connecting to %s. Negative connection cache for %s seconds\n", obj->parent->name, secs);
        return ODBC_FAIL;
    }
 
    res = SQLAllocHandle(SQL_HANDLE_DBC, obj->parent->env, &con);
 
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        ast_log(LOG_WARNING, "res_odbc: Error AllocHDB %d\n", res);
        obj->parent->last_negative_connect = ast_tvnow();
        return ODBC_FAIL;
    }
    SQLSetConnectAttr(con, SQL_LOGIN_TIMEOUT, (SQLPOINTER *)(long) obj->parent->conntimeout, 0);
    SQLSetConnectAttr(con, SQL_ATTR_CONNECTION_TIMEOUT, (SQLPOINTER *)(long) obj->parent->conntimeout, 0);
#ifdef NEEDTRACE
    SQLSetConnectAttr(con, SQL_ATTR_TRACE, &enable, SQL_IS_INTEGER);
    SQLSetConnectAttr(con, SQL_ATTR_TRACEFILE, tracefile, strlen(tracefile));
#endif
 
    res = SQLConnect(con,
           (SQLCHAR *) obj->parent->dsn, SQL_NTS,
           (SQLCHAR *) obj->parent->username, SQL_NTS,
           (SQLCHAR *) obj->parent->password, SQL_NTS);
 
    if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO)) {
        SQLGetDiagRec(SQL_HANDLE_DBC, con, 1, state, &err, msg, 100, &mlen);
        obj->parent->last_negative_connect = ast_tvnow();
        ast_log(LOG_WARNING, "res_odbc: Error SQLConnect=%d errno=%d %s\n", res, (int)err, msg);
        if ((res = SQLFreeHandle(SQL_HANDLE_DBC, con)) != SQL_SUCCESS) {
            SQLGetDiagRec(SQL_HANDLE_DBC, con, 1, state, &err, msg, 100, &mlen);
            ast_log(LOG_WARNING, "Unable to deallocate database handle %p? %d errno=%d %s\n", con, res, (int)err, msg);
        }
        return ODBC_FAIL;
    } else {
        ast_debug(3, "res_odbc: Connected to %s [%s (%p)]\n", obj->parent->name, obj->parent->dsn, obj);
    }
 
    obj->con = con;
    return ODBC_SUCCESS;
}
 
static int reload(void)
{
    struct odbc_cache_tables *table;
    struct odbc_class *class;
    struct ao2_iterator aoi = ao2_iterator_init(class_container, 0);
 
    /* First, mark all to be purged */
    while ((class = ao2_iterator_next(&aoi))) {
        class->delme = 1;
        ao2_ref(class, -1);
    }
    ao2_iterator_destroy(&aoi);
 
    load_odbc_config();
 
    aoi = ao2_iterator_init(class_container, 0);
    while ((class = ao2_iterator_next(&aoi))) {
        if (class->delme) {
            ao2_unlink(class_container, class);
        }
        ao2_ref(class, -1);
    }
    ao2_iterator_destroy(&aoi);
 
    /* Empty the cache; it will get rebuilt the next time the tables are needed. */
    AST_RWLIST_WRLOCK(&odbc_tables);
    while ((table = AST_RWLIST_REMOVE_HEAD(&odbc_tables, list))) {
        destroy_table_cache(table);
    }
    AST_RWLIST_UNLOCK(&odbc_tables);
 
    return 0;
}
 
static int unload_module(void)
{
    ao2_cleanup(class_container);
    ast_cli_unregister_multiple(cli_odbc, ARRAY_LEN(cli_odbc));
 
    return 0;
}
 
static int load_module(void)
{
    class_container = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_MUTEX, 0, NULL, ao2_match_by_addr);
    if (!class_container) {
        return AST_MODULE_LOAD_DECLINE;
    }
 
    if (load_odbc_config() == -1) {
        return AST_MODULE_LOAD_DECLINE;
    }
 
    ast_module_shutdown_ref(ast_module_info->self);
    ast_cli_register_multiple(cli_odbc, ARRAY_LEN(cli_odbc));
 
    return AST_MODULE_LOAD_SUCCESS;
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "ODBC resource",
    .support_level = AST_MODULE_SUPPORT_CORE,
    .load = load_module,
    .unload = unload_module,
    .reload = reload,
    .load_pri = AST_MODPRI_REALTIME_DEPEND,
    .requires = "res_odbc_transaction",
);