diff --git a/core/polyfills.php b/core/polyfills.php
index 1dfee641..437b25ed 100644
--- a/core/polyfills.php
+++ b/core/polyfills.php
@@ -173,7 +173,6 @@ function stream_file(string $file, int $start, int $end): void
 {
     $fp = fopen($file, 'r');
     try {
-        set_time_limit(0);
         fseek($fp, $start);
         $buffer = 1024 * 1024;
         while (!feof($fp) && ($p = ftell($fp)) <= $end) {
diff --git a/core/timeout.php b/core/timeout.php
new file mode 100644
index 00000000..ee868d9c
--- /dev/null
+++ b/core/timeout.php
@@ -0,0 +1,32 @@
+<?php
+
+class TimeoutException extends RuntimeException
+{
+}
+
+class Timeout
+{
+    private $active;
+
+    public function set($seconds)
+    {
+        $this->active = true;
+        // declare(ticks = 1);
+        pcntl_signal(SIGALRM, [$this, 'handle'], true);
+        pcntl_alarm($seconds);
+        set_time_limit($seconds + 5);
+    }
+
+    public function clear()
+    {
+        set_time_limit(0);
+        $this->active = false;
+    }
+
+    public function handle($signal)
+    {
+        if ($this->active) {
+            throw new TimeoutException();
+        }
+    }
+}
diff --git a/ext/admin/main.php b/ext/admin/main.php
index b06d0f7c..95648585 100644
--- a/ext/admin/main.php
+++ b/ext/admin/main.php
@@ -37,7 +37,7 @@ class AdminPage extends Extension
 
     public function onPageRequest(PageRequestEvent $event)
     {
-        global $database, $page, $user;
+        global $database, $page, $user, $_shm_timeout;
 
         if ($event->page_matches("admin")) {
             if (!$user->can(Permissions::MANAGE_ADMINTOOLS)) {
@@ -51,7 +51,7 @@ class AdminPage extends Extension
 
                     if ($user->check_auth_token()) {
                         log_info("admin", "Util: $action");
-                        set_time_limit(0);
+                        $_shm_timeout->clear();
                         $database->set_timeout(null);
                         send_event($aae);
                     }
diff --git a/ext/bulk_add/main.php b/ext/bulk_add/main.php
index 9aed87dd..325cca1b 100644
--- a/ext/bulk_add/main.php
+++ b/ext/bulk_add/main.php
@@ -24,10 +24,10 @@ class BulkAdd extends Extension
 
     public function onPageRequest(PageRequestEvent $event)
     {
-        global $page, $user;
+        global $page, $user, $_shm_timeout;
         if ($event->page_matches("bulk_add")) {
             if ($user->can(Permissions::BULK_ADD) && $user->check_auth_token() && isset($_POST['dir'])) {
-                set_time_limit(0);
+                $_shm_timeout->clear();
                 $bae = send_event(new BulkAddEvent($_POST['dir']));
                 foreach ($bae->results as $result) {
                     $this->theme->add_status("Adding files", $result);
diff --git a/ext/bulk_add_csv/main.php b/ext/bulk_add_csv/main.php
index 6dfcb488..4c00c251 100644
--- a/ext/bulk_add_csv/main.php
+++ b/ext/bulk_add_csv/main.php
@@ -11,10 +11,10 @@ class BulkAddCSV extends Extension
 
     public function onPageRequest(PageRequestEvent $event)
     {
-        global $page, $user;
+        global $page, $user, $_shm_timeout;
         if ($event->page_matches("bulk_add_csv")) {
             if ($user->can(Permissions::BULK_ADD) && $user->check_auth_token() && isset($_POST['csv'])) {
-                set_time_limit(0);
+                $_shm_timeout->clear();
                 $this->add_csv($_POST['csv']);
                 $this->theme->display_upload_results($page);
             }
diff --git a/ext/cron_uploader/main.php b/ext/cron_uploader/main.php
index 8da3c467..286d5e9a 100644
--- a/ext/cron_uploader/main.php
+++ b/ext/cron_uploader/main.php
@@ -350,7 +350,7 @@ class CronUploader extends Extension
 
         self::$IMPORT_RUNNING = true;
         try {
-            //set_time_limit(0);
+            //$_shm_timeout->clear();
 
             $output_subdir = date('Ymd-His', time());
             $image_queue = $this->generate_image_queue();
diff --git a/ext/rule34/main.php b/ext/rule34/main.php
index 22000a0a..f68f5582 100644
--- a/ext/rule34/main.php
+++ b/ext/rule34/main.php
@@ -114,7 +114,7 @@ class Rule34 extends Extension
         global $database, $page, $user;
 
         # Database might not be connected at this point...
-        #$database->set_timeout(DATABASE_TIMEOUT+15000); // deleting users can take a while
+        #$database->set_timeout(null); // deleting users can take a while
 
         if (function_exists("sd_notify_watchdog")) {
             \sd_notify_watchdog();
diff --git a/ext/source_history/main.php b/ext/source_history/main.php
index db98272e..0048d7fd 100644
--- a/ext/source_history/main.php
+++ b/ext/source_history/main.php
@@ -180,6 +180,7 @@ class SourceHistory extends Extension
 
     protected function process_bulk_revert_request()
     {
+        global $_shm_timeout;
         if (isset($_POST['revert_name']) && !empty($_POST['revert_name'])) {
             $revert_name = $_POST['revert_name'];
         } else {
@@ -209,7 +210,7 @@ class SourceHistory extends Extension
             $revert_date = null;
         }
 
-        set_time_limit(0); // reverting changes can take a long time, disable php's timelimit if possible.
+        $_shm_timeout->clear(); // reverting changes can take a long time, disable php's timelimit if possible.
 
         // Call the revert function.
         $this->process_revert_all_changes($revert_name, $revert_ip, $revert_date);
diff --git a/ext/tag_history/main.php b/ext/tag_history/main.php
index 8b9d2a79..07bc4bba 100644
--- a/ext/tag_history/main.php
+++ b/ext/tag_history/main.php
@@ -178,6 +178,8 @@ class TagHistory extends Extension
 
     protected function process_bulk_revert_request()
     {
+        global $_shm_timeout;
+
         if (isset($_POST['revert_name']) && !empty($_POST['revert_name'])) {
             $revert_name = $_POST['revert_name'];
         } else {
@@ -207,7 +209,7 @@ class TagHistory extends Extension
             $revert_date = null;
         }
 
-        set_time_limit(0); // reverting changes can take a long time, disable php's timelimit if possible.
+        $_shm_timeout->clear(); // reverting changes can take a long time, disable php's timelimit if possible.
 
         // Call the revert function.
         $this->process_revert_all_changes($revert_name, $revert_ip, $revert_date);
diff --git a/index.php b/index.php
index c80883b6..f0b559a3 100644
--- a/index.php
+++ b/index.php
@@ -46,6 +46,8 @@ _set_up_shimmie_environment();
 $_tracer = new \EventTracer();
 $_tracer->begin("Bootstrap");
 _load_core_files();
+$_shm_timeout = new \Timeout();
+$_shm_timeout->set(((int)ini_get('max_execution_time')) || 30);
 $cache = loadCache(CACHE_DSN);
 $database = new Database(DATABASE_DSN);
 $config = new DatabaseConfig($database);