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func_odbc: Check connection status before executing queries. 

A recent change to func_odbc made it so that a single connection was
maintained per DSN. The problem was that the code was optimistic about
the health of the connection after initially opening it and did nothing
to re-connect in case the connection had died.

This change adds a check before executing a query to ensure that the
connection to the database is still up and running.

ASTERISK-25963 #close
Reported by Ross Beer

Change-Id: Id33c86eb04ff48ca088bb2e3086c27b3b683491d
This commit is contained in:
Mark Michelson 2016-04-27 13:23:37 -05:00
parent d1b9b96456
commit 2b150f0b80
1 changed files with 81 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

86
funcs/func_odbc.c
View File

@ -243,6 +243,42 @@ static struct dsn *create_dsn(const char *name)
return dsn;
}
static SQLHSTMT silent_execute(struct odbc_obj *obj, void *data);
/*!
* \brief Determine if the connection has died.
*
* \param connection The connection to check
* \retval 1 Yep, it's dead
* \retval 0 It's alive and well
*/
static int connection_dead(struct odbc_obj *connection)
{
SQLINTEGER dead;
SQLRETURN res;
SQLHSTMT stmt;
if (!connection) {
return 1;
}
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 direct
* execute of a probing statement and see if that succeeds instead
*/
stmt = ast_odbc_direct_execute(connection, silent_execute, "SELECT 1");
if (!stmt) {
return 1;
}
SQLFreeHandle(SQL_HANDLE_STMT, stmt);
return 0;
}
/*!
* \brief Retrieve a DSN, or create it if it does not exist.
*
@ -271,7 +307,26 @@ static struct dsn *get_dsn(const char *name)
return NULL;
}
ao2_lock(dsn->connection);
ao2_lock(dsn);
if (!dsn->connection) {
dsn->connection = ast_odbc_request_obj(name, 0);
if (!dsn->connection) {
ao2_unlock(dsn);
ao2_ref(dsn, -1);
return NULL;
}
return dsn;
}
if (connection_dead(dsn->connection)) {
ast_odbc_release_obj(dsn->connection);
dsn->connection = ast_odbc_request_obj(name, 0);
if (!dsn->connection) {
ao2_unlock(dsn);
ao2_ref(dsn, -1);
return NULL;
}
}
return dsn;
}
@ -288,7 +343,7 @@ static void *release_dsn(struct dsn *dsn)
return NULL;
}
ao2_unlock(dsn->connection);
ao2_unlock(dsn);
ao2_ref(dsn, -1);
return NULL;
@ -323,7 +378,16 @@ static void odbc_datastore_free(void *data)
ast_free(result);
}
static SQLHSTMT generic_execute(struct odbc_obj *obj, void *data)
/*!
* \brief Common execution function for SQL queries.
*
* \param obj DB connection
* \param data The query to execute
* \param silent If true, do not print warnings on failure
* \retval NULL Failed to execute query
* \retval non-NULL The executed statement
*/
static SQLHSTMT execute(struct odbc_obj *obj, void *data, int silent)
{
int res;
char *sql = data;
@ -337,7 +401,7 @@ static SQLHSTMT generic_execute(struct odbc_obj *obj, void *data)
res = SQLExecDirect(stmt, (unsigned char *)sql, SQL_NTS);
if ((res != SQL_SUCCESS) && (res != SQL_SUCCESS_WITH_INFO) && (res != SQL_NO_DATA)) {
if (res == SQL_ERROR) {
if (res == SQL_ERROR && !silent) {
int i;
SQLINTEGER nativeerror=0, numfields=0;
SQLSMALLINT diagbytes=0;
@ -354,7 +418,9 @@ static SQLHSTMT generic_execute(struct odbc_obj *obj, void *data)
}
}
ast_log(LOG_WARNING, "SQL Exec Direct failed (%d)![%s]\n", res, sql);
if (!silent) {
ast_log(LOG_WARNING, "SQL Exec Direct failed (%d)![%s]\n", res, sql);
}
SQLCloseCursor(stmt);
SQLFreeHandle(SQL_HANDLE_STMT, stmt);
return NULL;
@ -363,6 +429,16 @@ static SQLHSTMT generic_execute(struct odbc_obj *obj, void *data)
return stmt;
}
static SQLHSTMT generic_execute(struct odbc_obj *obj, void *data)
{
return execute(obj, data, 0);
}
static SQLHSTMT silent_execute(struct odbc_obj *obj, void *data)
{
return execute(obj, data, 1);
}
/*
* Master control routine
*/