summaryrefslogtreecommitdiff
path: root/includes/ScopedPHPTimeout.php
diff options
context:
space:
mode:
Diffstat (limited to 'includes/ScopedPHPTimeout.php')
-rw-r--r--includes/ScopedPHPTimeout.php84
1 files changed, 84 insertions, 0 deletions
diff --git a/includes/ScopedPHPTimeout.php b/includes/ScopedPHPTimeout.php
new file mode 100644
index 00000000..d1493c30
--- /dev/null
+++ b/includes/ScopedPHPTimeout.php
@@ -0,0 +1,84 @@
+<?php
+/**
+ * Expansion of the PHP execution time limit feature for a function call.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Class to expand PHP execution time for a function call.
+ * Use this when performing changes that should not be interrupted.
+ *
+ * On construction, set_time_limit() is called and set to $seconds.
+ * If the client aborts the connection, PHP will continue to run.
+ * When the object goes out of scope, the timer is restarted, with
+ * the original time limit minus the time the object existed.
+ */
+class ScopedPHPTimeout {
+ protected $startTime; // float; seconds
+ protected $oldTimeout; // integer; seconds
+ protected $oldIgnoreAbort; // boolean
+
+ protected static $stackDepth = 0; // integer
+ protected static $totalCalls = 0; // integer
+ protected static $totalElapsed = 0; // float; seconds
+
+ /* Prevent callers in infinite loops from running forever */
+ const MAX_TOTAL_CALLS = 1000000;
+ const MAX_TOTAL_TIME = 300; // seconds
+
+ /**
+ * @param $seconds integer
+ */
+ public function __construct( $seconds ) {
+ if ( ini_get( 'max_execution_time' ) > 0 ) { // CLI uses 0
+ if ( self::$totalCalls >= self::MAX_TOTAL_CALLS ) {
+ trigger_error( "Maximum invocations of " . __CLASS__ . " exceeded." );
+ } elseif ( self::$totalElapsed >= self::MAX_TOTAL_TIME ) {
+ trigger_error( "Time limit within invocations of " . __CLASS__ . " exceeded." );
+ } elseif ( self::$stackDepth > 0 ) { // recursion guard
+ trigger_error( "Resursive invocation of " . __CLASS__ . " attempted." );
+ } else {
+ $this->oldIgnoreAbort = ignore_user_abort( true );
+ $this->oldTimeout = ini_set( 'max_execution_time', $seconds );
+ $this->startTime = microtime( true );
+ ++self::$stackDepth;
+ ++self::$totalCalls; // proof against < 1us scopes
+ }
+ }
+ }
+
+ /**
+ * Restore the original timeout.
+ * This does not account for the timer value on __construct().
+ */
+ public function __destruct() {
+ if ( $this->oldTimeout ) {
+ $elapsed = microtime( true ) - $this->startTime;
+ // Note: a limit of 0 is treated as "forever"
+ set_time_limit( max( 1, $this->oldTimeout - (int)$elapsed ) );
+ // If each scoped timeout is for less than one second, we end up
+ // restoring the original timeout without any decrease in value.
+ // Thus web scripts in an infinite loop can run forever unless we
+ // take some measures to prevent this. Track total time and calls.
+ self::$totalElapsed += $elapsed;
+ --self::$stackDepth;
+ ignore_user_abort( $this->oldIgnoreAbort );
+ }
+ }
+}