From 3ecc840572ac2a208859cd0d31f7125fc015b75f Mon Sep 17 00:00:00 2001
From: Stephen Shkardoon <ss23@ss23.geek.nz>
Date: Fri, 22 Mar 2013 03:04:51 +1300
Subject: [PATCH] Check for ALTER TABLE in installer (fixes #853)

---
 dev/install/DatabaseConfigurationHelper.php   | 10 +++++
 .../MySQLDatabaseConfigurationHelper.php      | 41 +++++++++++++++++++
 dev/install/install.php5                      | 27 +++++++++++-
 3 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/dev/install/DatabaseConfigurationHelper.php b/dev/install/DatabaseConfigurationHelper.php
index 2a194c6b5..fd086b26e 100644
--- a/dev/install/DatabaseConfigurationHelper.php
+++ b/dev/install/DatabaseConfigurationHelper.php
@@ -39,4 +39,14 @@ interface DatabaseConfigurationHelper {
 	 */
 	public function requireDatabaseOrCreatePermissions($databaseConfig);
 
+
+	/**
+	 * Ensure we have permissions to alter tables.
+	 *
+	 * @param array $databaseConfig Associative array of db configuration, e.g. "server", "username" etc
+	 * @return array Result - e.g. array('okay' => true, 'applies' => true), where applies is whether
+	 * the test is relevant for the database
+	 */
+	public function requireDatabaseAlterPermissions($databaseConfig);
+
 }
diff --git a/dev/install/MySQLDatabaseConfigurationHelper.php b/dev/install/MySQLDatabaseConfigurationHelper.php
index f86009610..dec1044e1 100644
--- a/dev/install/MySQLDatabaseConfigurationHelper.php
+++ b/dev/install/MySQLDatabaseConfigurationHelper.php
@@ -134,4 +134,45 @@ class MySQLDatabaseConfigurationHelper implements DatabaseConfigurationHelper {
 		);
 	}
 
+	/**
+	 * Ensure we have permissions to alter tables.
+	 * 
+	 * @param array $databaseConfig Associative array of db configuration, e.g. "server", "username" etc
+	 * @return array Result - e.g. array('okay' => true, 'applies' => true), where applies is whether
+	 * the test is relevant for the database
+	 */
+	public function requireDatabaseAlterPermissions($databaseConfig) {
+		$success = false;
+		$conn = new MySQLi($databaseConfig['server'], $databaseConfig['username'], $databaseConfig['password']);
+		if($conn) {
+			if ($res = $conn->query('SHOW GRANTS')) {
+				// Annoyingly, MySQL 'escapes' the database, so we need to do it too.
+				$db = str_replace(array('%', '_', '`'), array('\%', '\_', '``'), $databaseConfig['database']);
+				while ($row = $res->fetch_array()) {
+					if (preg_match('/^GRANT (.+) ON (.+) TO/', $row[0], $matches) && (count($matches) == 2)) {
+						// Need to change to an array of permissions, because ALTER is contained in ALTER ROUTINES.
+						$permission = array_map('trim', explode(',', $matches[1]));
+						$on_database = $matches[2];
+						// The use of both ` and " is because of ANSI mode.
+						if (in_array('ALL PRIVILEGES', $permission) and (
+								($on_database == '*.*') or ($on_database == '`' . $db . '`.*')
+								or ($on_database == '"' . $db . '".*'))) {
+							$success = true;
+							break;
+						}
+						if (in_array('ALTER', $permission) and (
+								($on_database == '*.*') or ($on_database == '`' . $db . '`.*')
+								or ($on_database == '"' . $db . '".*'))) {
+							$success = true;
+							break;
+						}
+					}
+				}
+			}
+		}
+		return array(
+			'success' => $success,
+			'applies' => true
+		);
+	}
 }
diff --git a/dev/install/install.php5 b/dev/install/install.php5
index 08aff9a80..2eaae5872 100644
--- a/dev/install/install.php5
+++ b/dev/install/install.php5
@@ -311,14 +311,23 @@ class InstallRequirements {
 							'Version ' . $this->getDatabaseConfigurationHelper($databaseConfig['type'])->getDatabaseVersion($databaseConfig)
 						)
 					)) {
-						$this->requireDatabaseOrCreatePermissions(
+						if($this->requireDatabaseOrCreatePermissions(
 							$databaseConfig,
 							array(
 								"Database Configuration",
 								"Can I access/create the database",
 								"I can't create new databases and the database '$databaseConfig[database]' doesn't exist"
 							)
-						);
+						)) {
+							$this->requireDatabaseAlterPermissions(
+								$databaseConfig,
+								array(
+									"Database Configuration",
+									"Can I ALTER tables",
+									"I don't have permission to ALTER tables"
+								)
+							);
+						}
 					}
 				}
 			}
@@ -913,6 +922,20 @@ class InstallRequirements {
 		}
 	}
 
+	function requireDatabaseAlterPermissions($databaseConfig, $testDetails) {
+		$this->testing($testDetails);
+		$helper = $this->getDatabaseConfigurationHelper($databaseConfig['type']);
+		$result = $helper->requireDatabaseAlterPermissions($databaseConfig);
+		if ($result['success']) {
+			return true;
+		} else {
+			$testDetails[2] = "Silverstripe cannot alter tables. This won't prevent installation, however it may "
+					. "cause issues if you try to run a /dev/build once installed.";
+			$this->warning($testDetails);
+			return;
+		}
+	}
+
 	function requireServerVariables($varNames, $errorMessage) {
 		//$this->testing($testDetails);
 		foreach($varNames as $varName) {