Fix GH-9812: memory leak on repeated include with file_cache_only=1

With opcache.file_cache_only=1 every include allocates a fresh
arena in zend_file_cache_script_load() and it leaks. Looks like
zend_arena_release() only runs when cache_it is set, which is the SHM
path. CG(arena) only resets at request shutdown, so I think memory just
keeps growing.

My attempt: per-request hashtable in ZCG, resolved path ->
zend_persistent_script. First include fills it, next ones should reuse
the arena allocation. Freeing it in
accel_post_deactivate seems to work since it runs before
zend_arena_destroy and shutdown_memory_manager, so entries and buckets
should still be alive.

Fixed GH-9812
Closes GH-9812

Author: pronskiy

ext/opcache/ZendAccelerator.c

@@ -1900,7 +1900,7 @@ static zend_persistent_script *opcache_compile_file(zend_file_handle *file_handl
 
 static zend_op_array *file_cache_compile_file(zend_file_handle *file_handle, int type)
 {
-	zend_persistent_script *persistent_script;
+	zend_persistent_script *persistent_script = NULL;
 	zend_op_array *op_array = NULL;
 	bool from_memory; /* if the script we've got is stored in SHM */
 
@@ -1923,11 +1923,35 @@ static zend_op_array *file_cache_compile_file(zend_file_handle *file_handle, int
 	    }
 	}
 
-	HANDLE_BLOCK_INTERRUPTIONS();
-	SHM_UNPROTECT();
-	persistent_script = zend_file_cache_script_load(file_handle);
-	SHM_PROTECT();
-	HANDLE_UNBLOCK_INTERRUPTIONS();
+	/* In file_cache_only mode each call to zend_file_cache_script_load()
+	 * allocates a fresh per-request arena buffer that is never released
+	 * (see GH-9812). Reuse a previously loaded script for the same
+	 * resolved path so subsequent includes do not grow CG(arena). */
+	if (file_cache_only && file_handle->opened_path) {
+		if (UNEXPECTED(!ZCG(file_cache_only_scripts).nTableSize)) {
+			zend_hash_init(&ZCG(file_cache_only_scripts), 8, NULL, NULL, 0);
+		}
+		persistent_script = zend_hash_find_ptr(
+			&ZCG(file_cache_only_scripts), file_handle->opened_path);
+		if (persistent_script && ZCG(accel_directives).validate_timestamps
+		 && zend_get_file_handle_timestamp(file_handle, NULL) != persistent_script->timestamp) {
+			zend_hash_del(&ZCG(file_cache_only_scripts), file_handle->opened_path);
+			persistent_script = NULL;
+		}
+	}
+
+	if (!persistent_script) {
+		HANDLE_BLOCK_INTERRUPTIONS();
+		SHM_UNPROTECT();
+		persistent_script = zend_file_cache_script_load(file_handle);
+		SHM_PROTECT();
+		HANDLE_UNBLOCK_INTERRUPTIONS();
+
+		if (persistent_script && file_cache_only && file_handle->opened_path) {
+			zend_hash_add_new_ptr(&ZCG(file_cache_only_scripts),
+				file_handle->opened_path, persistent_script);
+		}
+	}
 	if (persistent_script) {
 		/* see bug #15471 (old BTS) */
 		if (persistent_script->script.filename) {
@@ -2820,6 +2844,12 @@ zend_result accel_post_deactivate(void)
 		ZCG(cwd) = NULL;
 	}
 
+	if (ZCG(file_cache_only_scripts).nTableSize) {
+		/* See GH-9812 */
+		zend_hash_destroy(&ZCG(file_cache_only_scripts));
+		memset(&ZCG(file_cache_only_scripts), 0, sizeof(HashTable));
+	}
+
 	if (!ZCG(enabled) || !accel_startup_ok) {
 		return SUCCESS;
 	}

ext/opcache/ZendAccelerator.h

@@ -227,6 +227,8 @@ typedef struct _zend_accel_globals {
 	zend_persistent_script *cache_persistent_script;
 	/* preallocated buffer for keys */
 	zend_string            *key;
+	/* per-process cache to avoid leaks on repeated includes when opcache.file_cache_only=1. */
+	HashTable               file_cache_only_scripts;
 } zend_accel_globals;
 
 typedef struct _zend_string_table {

ext/opcache/tests/gh9812.inc

@@ -0,0 +1,2 @@
+<?php
+return;

ext/opcache/tests/gh9812.phpt

@@ -0,0 +1,55 @@
+--TEST--
+GH-9812: memory usage grows on repeated include with opcache.file_cache_only=1
+--SKIPIF--
+<?php
+@mkdir(__DIR__ . '/gh9812_cache', 0777, true);
+?>
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.jit=disable
+opcache.file_cache="{PWD}/gh9812_cache"
+opcache.file_cache_only=1
+opcache.file_update_protection=0
+--EXTENSIONS--
+opcache
+--FILE--
+<?php
+
+$file = __DIR__ . '/gh9812.inc';
+
+// Warm-up: write the script into the file cache
+require $file;
+require $file;
+
+$baseline = memory_get_usage();
+for ($i = 0; $i < 200; $i++) {
+    require $file;
+}
+$delta = memory_get_usage() - $baseline;
+
+// Allow a small headroom for VM/JIT.
+echo $delta < 4096 ? "stable\n" : "leaking: $delta bytes\n";
+
+?>
+--CLEAN--
+<?php
+function removeDirRecursive($dir) {
+    if (!is_dir($dir)) return;
+    $iterator = new RecursiveIteratorIterator(
+        new RecursiveDirectoryIterator($dir, RecursiveDirectoryIterator::SKIP_DOTS),
+        RecursiveIteratorIterator::CHILD_FIRST
+    );
+    foreach ($iterator as $fileinfo) {
+        if ($fileinfo->isDir()) {
+            @rmdir($fileinfo->getRealPath());
+        } else {
+            @unlink($fileinfo->getRealPath());
+        }
+    }
+    @rmdir($dir);
+}
+removeDirRecursive(__DIR__ . '/gh9812_cache');
+?>
+--EXPECT--
+stable