From 50a0efdda814efaaf0dfe7861fdc785429639a3b Mon Sep 17 00:00:00 2001
From: Mike Schroder <mikeschroder@git.wordpress.org>
Date: Thu, 25 Jun 2020 07:13:22 +0000
Subject: [PATCH] Upgrade/Install: Invalidate OPcache for PHP files during
 updates.

When files are copied into place, check whether opcode invalidation is available and attempt to invalidate to avoid unintended behavior or fatal errors from themes, plugins, or core.

Introduces `wp_opcache_invalidate()` to allow safe invalidation of PHP files from opcode cache, and a filter, `wp_opcache_invalidate_file` to override the behavior.

Replaces the existing calls to `opcache_invalidate()` in the plugin and theme editors to use the new function.

Thanks to jnylen0 for porting over a patch from ClassicPress that provided much of the approach for what is being committed.

Props nigro.simone, dd32, JasWSInc, szepe.viktor, swissspidy, JanR, asalce, Garavani, pavelevap, pputzer, GregLone, benoitchantre, jadonn, doc987, kraftbj, Krstarica, jnylen0, nextendweb, williampatton, ayeshrajans, joostdevalk, stevenkussmaul, boogah, jorbin, mikeschroder.
Fixes #36455, #50354.

git-svn-id: https://develop.svn.wordpress.org/trunk@48160 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-admin/includes/class-core-upgrader.php |  1 +
 src/wp-admin/includes/file.php                | 81 +++++++++++++++++--
 src/wp-admin/includes/update-core.php         | 13 ++-
 3 files changed, 87 insertions(+), 8 deletions(-)

diff --git a/src/wp-admin/includes/class-core-upgrader.php b/src/wp-admin/includes/class-core-upgrader.php
index 7ef49f1f1c..d7305589bf 100644
--- a/src/wp-admin/includes/class-core-upgrader.php
+++ b/src/wp-admin/includes/class-core-upgrader.php
@@ -161,6 +161,7 @@ class Core_Upgrader extends WP_Upgrader {
 		}
 		$wp_filesystem->chmod( $wp_dir . 'wp-admin/includes/update-core.php', FS_CHMOD_FILE );
 
+		wp_opcache_invalidate( ABSPATH . 'wp-admin/includes/update-core.php' );
 		require_once ABSPATH . 'wp-admin/includes/update-core.php';
 
 		if ( ! function_exists( 'update_core' ) ) {
diff --git a/src/wp-admin/includes/file.php b/src/wp-admin/includes/file.php
index 08215e5d2b..ec01eb799a 100644
--- a/src/wp-admin/includes/file.php
+++ b/src/wp-admin/includes/file.php
@@ -498,9 +498,7 @@ function wp_edit_theme_plugin_file( $args ) {
 	if ( false === $written ) {
 		return new WP_Error( 'unable_to_write', __( 'Unable to write to file.' ) );
 	}
-	if ( 'php' === $extension && function_exists( 'opcache_invalidate' ) ) {
-		opcache_invalidate( $real_file, true );
-	}
+	wp_opcache_invalidate( $real_file, true );
 
 	if ( $is_active && 'php' === $extension ) {
 
@@ -608,9 +606,7 @@ function wp_edit_theme_plugin_file( $args ) {
 
 			// Roll-back file change.
 			file_put_contents( $real_file, $previous_content );
-			if ( function_exists( 'opcache_invalidate' ) ) {
-				opcache_invalidate( $real_file, true );
-			}
+			wp_opcache_invalidate( $real_file, true );
 
 			if ( ! isset( $result['message'] ) ) {
 				$message = __( 'Something went wrong.' );
@@ -1743,6 +1739,7 @@ function copy_dir( $from, $to, $skip_list = array() ) {
 					return new WP_Error( 'copy_failed_copy_dir', __( 'Could not copy file.' ), $to . $filename );
 				}
 			}
+			wp_opcache_invalidate( $to . $filename );
 		} elseif ( 'd' === $fileinfo['type'] ) {
 			if ( ! $wp_filesystem->is_dir( $to . $filename ) ) {
 				if ( ! $wp_filesystem->mkdir( $to . $filename, FS_CHMOD_DIR ) ) {
@@ -2277,3 +2274,75 @@ function wp_print_request_filesystem_credentials_modal() {
 	</div>
 	<?php
 }
+
+/**
+ * Attempt to clear the opcode cache for an individual PHP file.
+ *
+ * This function can be called safely without having to check the file extension
+ * or availability of the OPcache extension.
+ *
+ * Whether or not invalidation is possible is cached to improve performance.
+ *
+ * @since 5.5
+ *
+ * @link https://www.php.net/manual/en/function.opcache-invalidate.php
+ *
+ * @param string $filepath Path to the file, including extension, for which the opcode cache is to be cleared.
+ * @param bool   $force    Invalidate even if the modification time is not newer than the file in cache. Default `false`.
+ *
+ * @return bool `true` if opcache was invalidated for `$filepath`, or there was nothing to invalidate.
+ *              `false` if opcache invalidation is not available, or is disabled via filter.
+ */
+function wp_opcache_invalidate( $filepath, $force = false ) {
+	static $can_invalidate = null;
+
+	/*
+	 * Check to see if WordPress is able to run `opcache_invalidate()` or not, and cache the value.
+	 *
+	 * First, check to see if the function is available to call, then if the host has restricted
+	 * the ability to run the function to avoid a PHP warning.
+	 *
+	 * `opcache.restrict_api` can specify the path for files allowed to call `opcache_invalidate()`.
+	 *
+	 * If the host has this set, check whether the path in `opcache.restrict_api` matches
+	 * the beginning of the path of the origin file.
+	 *
+	 * `$_SERVER['SCRIPT_FILENAME']` approximates the origin file's path, but
+	 * `realpath()` is necessary because `SCRIPT_FILENAME` can be a relative path
+	 * when run from CLI.
+	 *
+	 * For more details, see:
+	 * - https://www.php.net/manual/en/opcache.configuration.php
+	 * - https://www.php.net/manual/en/reserved.variables.server.php
+	 * - https://core.trac.wordpress.org/ticket/36455
+	 */
+	if ( $can_invalidate === null ) {
+		$can_invalidate = function_exists( 'opcache_invalidate' ) &&
+			( ! ini_get( 'opcache.restrict_api' ) ||
+				stripos( realpath( $_SERVER['SCRIPT_FILENAME'] ), ini_get( 'opcache.restrict_api' ) ) === 0 );
+	}
+
+	// If invalidation is not available, return early.
+	if ( ! $can_invalidate ) {
+		return false;
+	}
+
+	// Verify that file to be invalidated has a PHP extension.
+	if ( ! preg_match( '/\.(?:php)$/i', $filepath ) ) {
+		return false;
+	}
+
+	/**
+	 * Filters whether to invalidate a file from the opcode cache.
+	 *
+	 * @since 5.5
+	 *
+	 * @param bool   $will_invalidate Whether WordPress will invalidate `$filename`. Default `true`.
+	 * @param string $filename        The PHP filename to invalidate.
+	 */
+	if ( apply_filters( 'wp_opcache_invalidate_file', true, $filepath ) ) {
+		return opcache_invalidate( $filepath, $force );
+	}
+
+	return false;
+}
diff --git a/src/wp-admin/includes/update-core.php b/src/wp-admin/includes/update-core.php
index 935f1a7303..240d6be4ee 100644
--- a/src/wp-admin/includes/update-core.php
+++ b/src/wp-admin/includes/update-core.php
@@ -1318,14 +1318,18 @@ function update_core( $from, $to ) {
  *
  * Assumes that WP_Filesystem() has already been called and setup.
  *
- * This is a temporary function for the 3.1 -> 3.2 upgrade, as well as for those
- * upgrading to 3.7+.
+ * This is a standalone copy of the `copy_dir()` function that is used to
+ * upgrade the core files. It is placed here so that the version of this
+ * function from the *new* WordPress version will be called.
+ *
+ * It was initially added for the 3.1 -> 3.2 upgrade.
  *
  * @ignore
  * @since 3.2.0
  * @since 3.7.0 Updated not to use a regular expression for the skip list.
  *
  * @see copy_dir()
+ * @link https://core.trac.wordpress.org/ticket/17173
  *
  * @global WP_Filesystem_Base $wp_filesystem
  *
@@ -1355,6 +1359,11 @@ function _copy_dir( $from, $to, $skip_list = array() ) {
 					return new WP_Error( 'copy_failed__copy_dir', __( 'Could not copy file.' ), $to . $filename );
 				}
 			}
+
+			// `wp_opcache_invalidate()` only exists in WordPress 5.5, so don't run it when upgrading to 5.5.
+			if ( function_exists( 'wp_opcache_invalidate' ) ) {
+				wp_opcache_invalidate( $to . $filename );
+			}
 		} elseif ( 'd' === $fileinfo['type'] ) {
 			if ( ! $wp_filesystem->is_dir( $to . $filename ) ) {
 				if ( ! $wp_filesystem->mkdir( $to . $filename, FS_CHMOD_DIR ) ) {