GlobalIdGenerator: include user id in file prefix

thomas-daniels · thomas-daniels · commit a132c8030011 · 2022-06-27T02:15:22.000+02:00
On systems where multiple users run MediaWiki installations (such as
shared hosting), it's needed to make the file prefix for the
GlobalIdGenerator unique per user, to prevent potential permission
errors due to colliding temporary files. This commit includes the
value of `getmyuid()` in the file prefix, as proposed in the comments of
task T268420.

Bug: T268420
Change-Id: I1abbce3e2394d3aa54cb058b96d9bf85aeec6b44
diff --git a/includes/libs/uuid/GlobalIdGenerator.php b/includes/libs/uuid/GlobalIdGenerator.php
@@ -37,6 +37,11 @@ class GlobalIdGenerator {
 
 	/** @var string Temporary directory */
 	protected $tmpDir;
+	/** @var string
+	 * File prefix containing user ID to prevent collisions
+	 * if multiple users run MediaWiki (T268420)
+	 */
+	protected $uniqueFilePrefix;
 	/** @var string Local file path */
 	protected $nodeIdFile;
 	/** @var string Node ID in binary (32 bits) */
@@ -92,12 +97,13 @@ public function __construct( $tempDirectory, $shellCallback ) {
 			throw new InvalidArgumentException( "No temp directory provided" );
 		}
 		$this->tmpDir = $tempDirectory;
-		$this->nodeIdFile = $tempDirectory . '/' . self::FILE_PREFIX . '-UID-nodeid';
+		$this->uniqueFilePrefix = self::FILE_PREFIX . getmyuid();
+		$this->nodeIdFile = $tempDirectory . '/' . $this->uniqueFilePrefix . '-UID-nodeid';
 		// If different processes run as different users, they may have different temp dirs.
 		// This is dealt with by initializing the clock sequence number and counters randomly.
-		$this->lockFile88 = $tempDirectory . '/' . self::FILE_PREFIX . '-UID-88';
-		$this->lockFile128 = $tempDirectory . '/' . self::FILE_PREFIX . '-UID-128';
-		$this->lockFileUUID = $tempDirectory . '/' . self::FILE_PREFIX . '-UUID-128';
+		$this->lockFile88 = $tempDirectory . '/' . $this->uniqueFilePrefix . '-UID-88';
+		$this->lockFile128 = $tempDirectory . '/' . $this->uniqueFilePrefix . '-UID-128';
+		$this->lockFileUUID = $tempDirectory . '/' . $this->uniqueFilePrefix . '-UUID-128';
 
 		$this->shellCallback = $shellCallback;
 	}
@@ -373,7 +379,7 @@ protected function getSequentialPerNodeIDs( $bucket, $bits, $count, $flags ) {
 			throw new RuntimeException( "Requested bit size ($bits) is out of range." );
 		}
 
-		$path = $this->tmpDir . '/' . self::FILE_PREFIX . '-' . rawurlencode( $bucket ) . '-48';
+		$path = $this->tmpDir . '/' . $this->uniqueFilePrefix . '-' . rawurlencode( $bucket ) . '-48';
 		// Get the UID lock file handle
 		if ( isset( $this->fileHandles[$path] ) ) {
 			$handle = $this->fileHandles[$path];
