From 2b150f0b8095f0297e3cf49e6428267e03299afb Mon Sep 17 00:00:00 2001
From: Mark Michelson <mmichelson@digium.com>
Date: Wed, 27 Apr 2016 13:23:37 -0500
Subject: [PATCH] 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
---
funcs/func_odbc.c | 86 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 81 insertions(+), 5 deletions(-)
diff --git a/funcs/func_odbc.c b/funcs/func_odbc.c
index ca15d703fc..d8ffd90bbd 100644
--- a/funcs/func_odbc.c
+++ b/funcs/func_odbc.c
@@ -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
*/
--
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