Opcache: Introduce ABI-based versioning for file cache portability

.gitignore

@@ -98,6 +98,7 @@ config.h.in
 /main/php_config.h.in
 /main/php_config.h
 /Zend/zend_config.h
+/Zend/zend_abi_signature.h
 
 # ------------------------------------------------------------------------------
 # Manual (man 1 and 8) pages generated from templates for *nix alike systems
@@ -125,6 +126,7 @@ config.h.in
 # ------------------------------------------------------------------------------
 # Executable binaries and scripts generated during the build process
 # ------------------------------------------------------------------------------
+/Zend/gen_abi_sig
 /ext/phar/phar.phar
 /ext/phar/phar.php
 /pear/install-pear-nozlib.phar

Zend/Makefile.frag

@@ -42,3 +42,28 @@ vm.gen.intermediate: $(srcdir)/zend_vm_def.h $(srcdir)/zend_vm_execute.skl $(src
 $(builddir)/zend_highlight.lo $(builddir)/zend_compile.lo: $(srcdir)/zend_language_parser.h
 
 Zend/zend_execute.lo: $(srcdir)/zend_vm_execute.h $(srcdir)/zend_vm_opcodes.h
+
+# Define the headers that constitute the ABI
+ABI_HEADERS = \
+	$(top_srcdir)/Zend/zend_types.h \
+	$(top_srcdir)/Zend/zend_API.h \
+	$(top_srcdir)/Zend/zend_compile.h \
+	$(top_srcdir)/ext/opcache/zend_persist.h \
+	$(top_srcdir)/Zend/zend_vm_opcodes.h
+
+# Rule to build our generator program.
+# This is a simple, self-contained C file with no special dependencies.
+Zend/gen_abi_sig: Zend/gen_abi_sig.c
+	$(CC) $(CFLAGS_CLEAN) $(EXTRA_CFLAGS) $< -o $@
+
+# Rule to generate the ABI signature string and embed it into a header file
+Zend/zend_abi_signature.h: Zend/gen_abi_sig $(ABI_HEADERS)
+	@echo "Generating Opcache ABI Signature..."
+	@echo "/* This file is automatically generated. DO NOT EDIT. */" > $@
+	@echo "#ifndef ZEND_ABI_SIGNATURE_H" >> $@
+	@echo "#define ZEND_ABI_SIGNATURE_H" >> $@
+	@echo "static const char *zend_opcache_abi_signature = \"" `$(CC) -E $(CPPFLAGS) $(INCLUDES) $(ABI_HEADERS) | $(top_builddir)/Zend/gen_abi_sig` "\";" >> $@
+	@echo "#endif" >> $@
+
+# Ensure the system_id object depends on the generated header
+Zend/zend_system_id.lo: Zend/zend_abi_signature.h

Zend/gen_abi_sig.c

@@ -0,0 +1,74 @@
+/*
+   +----------------------------------------------------------------------+
+   | Zend Engine                                                          |
+   +----------------------------------------------------------------------+
+   | Copyright (c) Zend Technologies Ltd. (http://www.zend.com)           |
+   +----------------------------------------------------------------------+
+   | This source file is subject to version 2.00 of the Zend license,     |
+   | that is bundled with this package in the file LICENSE, and is        |
+   | available through the world-wide-web at the following url:           |
+   | http://www.zend.com/license/2_00.txt.                                |
+   | If you did not receive a copy of the Zend license and are unable to  |
+   | obtain it through the world-wide-web, please send a note to          |
+   | [email protected] so we can mail you a copy immediately.              |
+   +----------------------------------------------------------------------+
+   | Authors: Samuel Melrose <[email protected]>                        |
+   +----------------------------------------------------------------------+
+*/
+
+/*
+ * Opcache ABI Signature Generator
+ *
+ * This program is compiled and run during the PHP build process.
+ * It reads pre-processed C header source from stdin, calculates a
+ * CRC32 checksum of it, and prints the hex digest to stdout.
+ *
+ * A simple CRC32 is used as a lightweight, dependency-free way to
+ * detect changes in the core data structures.
+ */
+
+ #include <stdio.h>
+ #include <stdint.h>
+
+ /* A self-contained CRC32 implementation */
+ static uint32_t crc32_table[256];
+
+ static void build_crc32_table(void) {
+     for (uint32_t i = 0; i < 256; i++) {
+         uint32_t ch = i;
+         uint32_t crc = 0;
+         for (size_t j = 0; j < 8; j++) {
+             uint32_t b = (ch ^ crc) & 1;
+             crc >>= 1;
+             if (b) {
+                 crc = crc ^ 0xEDB88320;
+             }
+             ch >>= 1;
+         }
+         crc32_table[i] = crc;
+     }
+ }
+
+ static uint32_t crc32_update(uint32_t crc, const unsigned char *buf, size_t len) {
+     crc = ~crc;
+     while (len--) {
+         crc = (crc >> 8) ^ crc32_table[(crc ^ *buf++) & 0xFF];
+     }
+     return ~crc;
+ }
+
+ int main(int argc, char *argv[]) {
+     uint32_t crc = 0;
+     unsigned char buf[4096];
+     size_t n;
+
+     build_crc32_table();
+
+     while ((n = fread(buf, 1, sizeof(buf), stdin)) > 0) {
+         crc = crc32_update(crc, buf, n);
+     }
+
+     printf("%08x", crc);
+
+     return 0;
+ }

Zend/zend.c

@@ -278,6 +278,7 @@ ZEND_INI_BEGIN()
 	/* Subtracted from the max allowed stack size, as a buffer, when checking for overflow. 0: auto detect. */
 	STD_ZEND_INI_ENTRY("zend.reserved_stack_size",	"0",	ZEND_INI_SYSTEM,	OnUpdateReservedStackSize,	reserved_stack_size,		zend_executor_globals,	executor_globals)
 #endif
+	STD_ZEND_INI_BOOLEAN("zend.portable_build",		"0",	ZEND_INI_SYSTEM,	OnUpdateBool, portable_build, zend_executor_globals, executor_globals)
 
 ZEND_INI_END()
 

Zend/zend_globals.h

@@ -249,6 +249,9 @@ struct _zend_executor_globals {
 	/* timeout support */
 	zend_long timeout_seconds;
 
+	/* portable system_id */
+	bool portable_build;
+
 	HashTable *ini_directives;
 	HashTable *modified_ini_directives;
 	zend_ini_entry *error_reporting_ini_entry;

Zend/zend_system_id.c

@@ -18,6 +18,7 @@
 #include "php.h"
 #include "zend_system_id.h"
 #include "zend_extensions.h"
+#include "zend_abi_signature.h"
 #include "ext/standard/md5.h"
 #include "ext/hash/php_hash.h"
 
@@ -44,14 +45,6 @@ ZEND_API zend_result zend_add_system_entropy(const char *module_name, const char
 void zend_startup_system_id(void)
 {
 	PHP_MD5Init(&context);
-	PHP_MD5Update(&context, PHP_VERSION, sizeof(PHP_VERSION)-1);
-	PHP_MD5Update(&context, ZEND_EXTENSION_BUILD_ID, sizeof(ZEND_EXTENSION_BUILD_ID)-1);
-	PHP_MD5Update(&context, ZEND_BIN_ID, sizeof(ZEND_BIN_ID)-1);
-	if (strstr(PHP_VERSION, "-dev") != 0) {
-		/* Development versions may be changed from build to build */
-		PHP_MD5Update(&context, __DATE__, sizeof(__DATE__)-1);
-		PHP_MD5Update(&context, __TIME__, sizeof(__TIME__)-1);
-	}
 	zend_system_id[0] = '\0';
 }
 
@@ -66,6 +59,27 @@ void zend_finalize_system_id(void)
 	unsigned char digest[16];
 	uint8_t hooks = 0;
 
+	if (EG(portable_build)) {
+		/* Portable build mode: Use the ABI signature and major/minor version */
+		int major_version = PHP_MAJOR_VERSION;
+		int minor_version = PHP_MINOR_VERSION;
+
+		PHP_MD5Update(&context, (const unsigned char *)&major_version, sizeof(int));
+		PHP_MD5Update(&context, (const unsigned char *)&minor_version, sizeof(int));
+		PHP_MD5Update(&context, (const unsigned char *)zend_opcache_abi_signature, strlen(zend_opcache_abi_signature));
+	} else {
+		/* Default strict mode: Use the original full-fat build ID */
+		PHP_MD5Update(&context, PHP_VERSION, sizeof(PHP_VERSION)-1);
+		PHP_MD5Update(&context, ZEND_EXTENSION_BUILD_ID, sizeof(ZEND_EXTENSION_BUILD_ID)-1);
+		if (strstr(PHP_VERSION, "-dev") != 0) {
+			PHP_MD5Update(&context, __DATE__, sizeof(__DATE__)-1);
+			PHP_MD5Update(&context, __TIME__, sizeof(__TIME__)-1);
+		}
+	}
+
+	/* These are always critical for compatibility */
+	PHP_MD5Update(&context, ZEND_BIN_ID, sizeof(ZEND_BIN_ID)-1);
+
 	if (zend_ast_process) {
 		hooks |= ZEND_HOOK_AST_PROCESS;
 	}

ext/opcache/tests/cleanup_helper.inc

@@ -0,0 +1,19 @@
+<?php
+
+function removeDirRecursive($dir) {
+    if (!is_dir($dir)) return;
+    try {
+        $iterator = new RecursiveIteratorIterator(
+            new RecursiveDirectoryIterator($dir, RecursiveDirectoryIterator::SKIP_DOTS),
+            RecursiveIteratorIterator::CHILD_FIRST
+        );
+        foreach ($iterator as $fileinfo) {
+            if ($fileinfo->isDir()) {
+                @rmdir($fileinfo->getRealPath());
+            } else {
+                @unlink($fileinfo->getRealPath());
+            }
+        }
+        @rmdir($dir);
+    } catch (UnexpectedValueException $e) { @rmdir($dir); } catch (Exception $e) { @rmdir($dir); }
+}

ext/opcache/tests/portable_build.phpt

@@ -0,0 +1,79 @@
+--TEST--
+Zend Opcache: Check zend.portable_build system_id for file cache
+--SKIPIF--
+<?php
+// Ensure the cache directory exists BEFORE OPcache needs it
+$cacheDir = __DIR__ . '/portable_build_cache';
+if (!is_dir($cacheDir)) {
+    @mkdir($cacheDir, 0777, true);
+}
+// Check if mkdir failed potentially due to permissions
+if (!is_dir($cacheDir) || !is_writable($cacheDir)) {
+    die('skip Could not create or write to cache directory: ' . $cacheDir);
+}
+?>
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.jit=disable
+opcache.file_cache="{PWD}/portable_build_cache"
+--EXTENSIONS--
+opcache
+--FILE--
+<?php
+$cache_dir = __DIR__ . '/portable_build_cache';
+$test_file = __FILE__;
+
+$ini_settings_portable = [
+    'zend_extension'                    => 'opcache',
+    'opcache.enable'                    => 1,
+    'opcache.enable_cli'                => 1,
+    'opcache.jit'                       => 'disable',
+    'opcache.file_cache'                => $cache_dir,
+    'opcache.file_update_protection'    => 0,
+    'zend.portable_build'               => 1,
+];
+
+$ini_str_portable = '';
+foreach ($ini_settings_portable as $key => $value) {
+    $ini_str_portable .= "-d " . escapeshellarg("$key=$value") . " ";
+}
+
+$php_executable = getenv('TEST_PHP_EXECUTABLE');
+$command_portable = "$php_executable $ini_str_portable -r 'opcache_compile_file(\"$test_file\"); echo opcache_get_status()[\"system_id\"];'";
+$portable_system_id = trim(shell_exec($command_portable));
+
+if (substr(PHP_OS, 0, 3) === 'WIN') {
+    $pattern = $cache_dir . DIRECTORY_SEPARATOR . $portable_system_id . DIRECTORY_SEPARATOR . '*' . DIRECTORY_SEPARATOR . str_replace(':', '', __FILE__) . '.bin';
+} else {
+    $pattern = $cache_dir . DIRECTORY_SEPARATOR . $portable_system_id . DIRECTORY_SEPARATOR . __FILE__ . '.bin';
+}
+$cache_files = glob($pattern);
+if (count($cache_files) !== 1) {
+    die('Failed to find the generated cache file in ' . $cache_dir);
+}
+$cache_file_path = $cache_files[0];
+$cache_file_handle = fopen($cache_file_path, 'rb');
+fread($cache_file_handle, 8); // skip the first 8 bytes
+$header = fread($cache_file_handle, 32); // Read the first 32 bytes (the system_id)
+fclose($cache_file_handle);
+$stored_system_id = trim($header);
+
+var_dump($portable_system_id === $stored_system_id);
+
+$default_system_id = opcache_get_status()['system_id'];
+
+var_dump($portable_system_id === $default_system_id);
+
+?>
+--CLEAN--
+<?php
+require __DIR__ . '/cleanup_helper.inc';
+
+$cacheDir = __DIR__ . '/portable_build_cache';
+
+removeDirRecursive($cacheDir);
+?>
+--EXPECT--
+bool(true)
+bool(false)

ext/opcache/zend_accelerator_module.c

@@ -23,6 +23,7 @@
 
 #include "php.h"
 #include "ZendAccelerator.h"
+#include "zend_system_id.h"
 #include "zend_API.h"
 #include "zend_closures.h"
 #include "zend_shared_alloc.h"
@@ -651,6 +652,7 @@ ZEND_FUNCTION(opcache_get_status)
 
 	if (ZCG(accel_directives).file_cache) {
 		add_assoc_string(return_value, "file_cache", ZCG(accel_directives).file_cache);
+		add_assoc_stringl(return_value, "system_id", zend_system_id, 32);
 	}
 	if (file_cache_only) {
 		add_assoc_bool(return_value, "file_cache_only", 1);