Backport #2193: Update getUserName in impersonated security context in Azure SQL database

src/main/java/com/microsoft/sqlserver/jdbc/SQLServerDatabaseMetaData.java

@@ -1709,12 +1709,30 @@ public String getUserName() throws SQLServerException, SQLTimeoutException {
         }
         checkClosed();
         String result = "";
-        try (SQLServerStatement s = (SQLServerStatement) connection.createStatement();
-                SQLServerResultSet rs = s.executeQueryInternal("select system_user")) {
-            // Select system_user will always return a row.
-            boolean next = rs.next();
-            assert next;
-            result = rs.getString(1);
+        try (SQLServerStatement s = (SQLServerStatement) connection.createStatement()) {
+            try (SQLServerResultSet rs = s.executeQueryInternal("SELECT SYSTEM_USER")) {
+                // Select system_user will always return a row.
+                boolean next = rs.next();
+                assert next;
+                result = rs.getString(1);
+            } catch (SQLServerException e) {
+                // execution using impersonated security context is disallowed for Azure SQL Server so return CURRENT_USER instead
+                if (e.getErrorCode() == SQLServerException.IMPERSONATION_CONTEXT_NOT_SUPPORTED) {
+                    if (loggerExternal.isLoggable(Level.FINEST)) {
+                        loggerExternal.finest(toString()
+                                + " Impersonation context is not supported in this version of SQL Server. Re-try getting CURRENT_USER");
+                    }
+
+                    try (SQLServerResultSet rs = s.executeQueryInternal("SELECT CURRENT_USER")) {
+                        boolean next = rs.next();
+                        assert next;
+                        result = rs.getString(1);
+                    }
+                } else {
+                    // re-throw
+                    throw e;
+                }
+            }
         }
         return result;
     }

src/main/java/com/microsoft/sqlserver/jdbc/SQLServerException.java

@@ -66,8 +66,9 @@ public final class SQLServerException extends java.sql.SQLException {
     static final int LOGON_FAILED = 18456;
     static final int PASSWORD_EXPIRED = 18488;
     static final int USER_ACCOUNT_LOCKED = 18486;
-    static final java.util.logging.Logger exLogger = java.util.logging.Logger
-            .getLogger("com.microsoft.sqlserver.jdbc.internals.SQLServerException");
+
+    // Built-in function '%.*ls' in impersonation context is not supported in this version of SQL Server.
+    static final int IMPERSONATION_CONTEXT_NOT_SUPPORTED = 40529;
 
     // Facility for driver-specific error codes
     static final int DRIVER_ERROR_NONE = 0;
@@ -84,6 +85,9 @@ public final class SQLServerException extends java.sql.SQLException {
     static final int DATA_CLASSIFICATION_INVALID_LABEL_INDEX = 12;
     static final int DATA_CLASSIFICATION_INVALID_INFORMATION_TYPE_INDEX = 13;
 
+    static final java.util.logging.Logger exLogger = java.util.logging.Logger
+            .getLogger("com.microsoft.sqlserver.jdbc.internals.SQLServerException");
+
     /** driver error code */
     private int driverErrorCode = DRIVER_ERROR_NONE;
 

src/test/java/com/microsoft/sqlserver/jdbc/databasemetadata/DatabaseMetaDataTest.java

@@ -18,6 +18,7 @@
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.sql.CallableStatement;
 import java.sql.Connection;
 import java.sql.DatabaseMetaData;
 import java.sql.ResultSet;
@@ -43,6 +44,7 @@
 import com.microsoft.sqlserver.jdbc.RandomUtil;
 import com.microsoft.sqlserver.jdbc.SQLServerDataSource;
 import com.microsoft.sqlserver.jdbc.SQLServerDatabaseMetaData;
+import com.microsoft.sqlserver.jdbc.SQLServerException;
 import com.microsoft.sqlserver.jdbc.StringUtils;
 import com.microsoft.sqlserver.jdbc.TestResource;
 import com.microsoft.sqlserver.jdbc.TestUtils;
@@ -155,8 +157,6 @@ public void testGetURL() throws SQLException {
      * @throws SQLException
      */
     @Test
-    @Tag(Constants.xAzureSQLDW)
-    @Tag(Constants.xAzureSQLDB)
     public void testDBUserLogin() throws SQLException {
         try (Connection conn = getConnection()) {
             DatabaseMetaData databaseMetaData = conn.getMetaData();
@@ -187,6 +187,45 @@ public void testDBUserLogin() throws SQLException {
         }
     }
 
+    @Test
+    @Tag(Constants.xAzureSQLDW)
+    public void testImpersonateGetUserName() throws SQLException {
+        String newUser = "newUser" + UUID.randomUUID();
+
+        try (Connection conn = getConnection(); Statement stmt = conn.createStatement()) {
+            String escapedNewUser = AbstractSQLGenerator.escapeIdentifier(newUser);
+            String password = "password" + UUID.randomUUID();
+
+            stmt.execute("IF EXISTS (select * from sys.sysusers where name = '" + escapedNewUser + "') DROP USER"
+                    + escapedNewUser);
+
+            // create new user and login
+            try {
+                stmt.execute("CREATE USER " + escapedNewUser + " WITH password='" + password + "'");
+            } catch (SQLServerException e) {
+                // handle failed cases when database is master
+                if (e.getMessage().contains("contained database")) {
+                    stmt.execute("CREATE LOGIN " + escapedNewUser + " WITH password='" + password + "'");
+                    stmt.execute("CREATE USER " + escapedNewUser);
+                }
+            }
+
+            DatabaseMetaData databaseMetaData = conn.getMetaData();
+            try (CallableStatement asOtherUser = conn.prepareCall("EXECUTE AS USER = '" + newUser + "'")) {
+                asOtherUser.execute();
+                assertTrue(newUser.equalsIgnoreCase(databaseMetaData.getUserName()),
+                        TestResource.getResource("R_userNameNotMatch"));
+            } catch (Exception e) {
+                fail(TestResource.getResource("R_unexpectedErrorMessage") + e.getMessage());
+            } finally {
+                stmt.execute("IF EXISTS (select * from sys.sysusers where name = '" + escapedNewUser + "') DROP USER"
+                        + escapedNewUser);
+                stmt.execute("IF EXISTS (select * from sys.sysusers where name = '" + escapedNewUser + "') DROP LOGIN"
+                        + escapedNewUser);
+            }
+        }
+    }
+
     /**
      * Testing of {@link SQLServerDatabaseMetaData#getSchemas()}
      *