/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright © Zend Technologies Ltd., a subsidiary company of          |
   |     Perforce Software, Inc., and Contributors.                       |
   +----------------------------------------------------------------------+
   | This source file is subject to the Modified BSD License that is      |
   | bundled with this package in the file LICENSE, and is available      |
   | through the World Wide Web at <https://www.php.net/license/>.        |
   |                                                                      |
   | SPDX-License-Identifier: BSD-3-Clause                                |
   +----------------------------------------------------------------------+
   | Authors: Andi Gutmans <andi@php.net>                                 |
   |          Zeev Suraski <zeev@php.net>                                 |
   +----------------------------------------------------------------------+
*/

#include "zend_extensions.h"
#include "zend_system_id.h"

ZEND_API zend_llist zend_extensions;
ZEND_API uint32_t zend_extension_flags = 0;
ZEND_API int zend_op_array_extension_handles = 0;
ZEND_API int zend_internal_function_extension_handles = 0;
static int last_resource_number;

zend_result zend_load_extension(const char *path)
{
#if ZEND_EXTENSIONS_SUPPORT
	DL_HANDLE handle;

	handle = DL_LOAD(path);
	if (!handle) {
#ifndef ZEND_WIN32
		fprintf(stderr, "Failed loading %s:  %s\n", path, DL_ERROR());
#else
		fprintf(stderr, "Failed loading %s\n", path);
		/* See http://support.microsoft.com/kb/190351 */
		fflush(stderr);
#endif
		return FAILURE;
	}
#ifdef ZEND_WIN32
	char *err;
	if (!php_win32_image_compatible(handle, &err)) {
		zend_error(E_CORE_WARNING, "%s", err);
		return FAILURE;
	}
#endif
	return zend_load_extension_handle(handle, path);
#else
	fprintf(stderr, "Extensions are not supported on this platform.\n");
/* See http://support.microsoft.com/kb/190351 */
#ifdef ZEND_WIN32
	fflush(stderr);
#endif
	return FAILURE;
#endif
}

zend_result zend_load_extension_handle(DL_HANDLE handle, const char *path)
{
#if ZEND_EXTENSIONS_SUPPORT
	zend_extension *new_extension;

	const zend_extension_version_info *extension_version_info = (const zend_extension_version_info *) DL_FETCH_SYMBOL(handle, "extension_version_info");
	if (!extension_version_info) {
		extension_version_info = (const zend_extension_version_info *) DL_FETCH_SYMBOL(handle, "_extension_version_info");
	}
	new_extension = (zend_extension *) DL_FETCH_SYMBOL(handle, "zend_extension_entry");
	if (!new_extension) {
		new_extension = (zend_extension *) DL_FETCH_SYMBOL(handle, "_zend_extension_entry");
	}
	if (!extension_version_info || !new_extension) {
		fprintf(stderr, "%s doesn't appear to be a valid Zend extension\n", path);
/* See http://support.microsoft.com/kb/190351 */
#ifdef ZEND_WIN32
		fflush(stderr);
#endif
		DL_UNLOAD(handle);
		return FAILURE;
	}

	/* allow extension to proclaim compatibility with any Zend version */
	if (extension_version_info->zend_extension_api_no != ZEND_EXTENSION_API_NO &&(!new_extension->api_no_check || new_extension->api_no_check(ZEND_EXTENSION_API_NO) != SUCCESS)) {
		if (extension_version_info->zend_extension_api_no > ZEND_EXTENSION_API_NO) {
			fprintf(stderr, "%s requires Zend Engine API version %d.\n"
					"The Zend Engine API version %d which is installed, is outdated.\n\n",
					new_extension->name,
					extension_version_info->zend_extension_api_no,
					ZEND_EXTENSION_API_NO);
/* See http://support.microsoft.com/kb/190351 */
#ifdef ZEND_WIN32
			fflush(stderr);
#endif
			DL_UNLOAD(handle);
			return FAILURE;
		} else if (extension_version_info->zend_extension_api_no < ZEND_EXTENSION_API_NO) {
			fprintf(stderr, "%s requires Zend Engine API version %d.\n"
					"The Zend Engine API version %d which is installed, is newer.\n"
					"Contact %s at %s for a later version of %s.\n\n",
					new_extension->name,
					extension_version_info->zend_extension_api_no,
					ZEND_EXTENSION_API_NO,
					new_extension->author,
					new_extension->URL,
					new_extension->name);
/* See http://support.microsoft.com/kb/190351 */
#ifdef ZEND_WIN32
			fflush(stderr);
#endif
			DL_UNLOAD(handle);
			return FAILURE;
		}
	} else if (strcmp(ZEND_EXTENSION_BUILD_ID, extension_version_info->build_id) &&
	           (!new_extension->build_id_check || new_extension->build_id_check(ZEND_EXTENSION_BUILD_ID) != SUCCESS)) {
		fprintf(stderr, "Cannot load %s - it was built with configuration %s, whereas running engine is %s\n",
					new_extension->name, extension_version_info->build_id, ZEND_EXTENSION_BUILD_ID);
/* See http://support.microsoft.com/kb/190351 */
#ifdef ZEND_WIN32
		fflush(stderr);
#endif
		DL_UNLOAD(handle);
		return FAILURE;
	} else if (zend_get_extension(new_extension->name)) {
		fprintf(stderr, "Cannot load %s - it was already loaded\n", new_extension->name);
/* See http://support.microsoft.com/kb/190351 */
#ifdef ZEND_WIN32
		fflush(stderr);
#endif
		DL_UNLOAD(handle);
		return FAILURE;
	}

	zend_register_extension(new_extension, handle);
	return SUCCESS;
#else
	fprintf(stderr, "Extensions are not supported on this platform.\n");
/* See http://support.microsoft.com/kb/190351 */
#ifdef ZEND_WIN32
	fflush(stderr);
#endif
	return FAILURE;
#endif
}


void zend_register_extension(zend_extension *new_extension, DL_HANDLE handle)
{
#if ZEND_EXTENSIONS_SUPPORT
	zend_extension extension;

	extension = *new_extension;
	extension.handle = handle;

	zend_extension_dispatch_message(ZEND_EXTMSG_NEW_EXTENSION, &extension);

	zend_llist_add_element(&zend_extensions, &extension);

	if (extension.op_array_ctor) {
		zend_extension_flags |= ZEND_EXTENSIONS_HAVE_OP_ARRAY_CTOR;
	}
	if (extension.op_array_dtor) {
		zend_extension_flags |= ZEND_EXTENSIONS_HAVE_OP_ARRAY_DTOR;
	}
	if (extension.op_array_handler) {
		zend_extension_flags |= ZEND_EXTENSIONS_HAVE_OP_ARRAY_HANDLER;
	}
	if (extension.op_array_persist_calc) {
		zend_extension_flags |= ZEND_EXTENSIONS_HAVE_OP_ARRAY_PERSIST_CALC;
	}
	if (extension.op_array_persist) {
		zend_extension_flags |= ZEND_EXTENSIONS_HAVE_OP_ARRAY_PERSIST;
	}
	/*fprintf(stderr, "Loaded %s, version %s\n", extension.name, extension.version);*/
#endif
}


static void zend_extension_shutdown(zend_extension *extension)
{
#if ZEND_EXTENSIONS_SUPPORT
	if (extension->shutdown) {
		extension->shutdown(extension);
	}
#endif
}

/* int return due to zend linked list API */
static int zend_extension_startup(zend_extension *extension)
{
#if ZEND_EXTENSIONS_SUPPORT
	if (extension->startup) {
		if (extension->startup(extension)!=SUCCESS) {
			return 1;
		}
		zend_append_version_info(extension);
	}
#endif
	return 0;
}


void zend_startup_extensions_mechanism(void)
{
	/* Startup extensions mechanism */
	zend_llist_init(&zend_extensions, sizeof(zend_extension), (void (*)(void *)) zend_extension_dtor, 1);
	zend_op_array_extension_handles = 0;
	zend_internal_function_extension_handles = 0;
	last_resource_number = 0;
}


void zend_startup_extensions(void)
{
	zend_llist_apply_with_del(&zend_extensions, (int (*)(void *)) zend_extension_startup);
}


void zend_shutdown_extensions(void)
{
	zend_llist_apply(&zend_extensions, (llist_apply_func_t) zend_extension_shutdown);
	zend_llist_destroy(&zend_extensions);
}


void zend_extension_dtor(zend_extension *extension)
{
#if ZEND_EXTENSIONS_SUPPORT && !ZEND_DEBUG
	if (extension->handle && !getenv("ZEND_DONT_UNLOAD_MODULES")) {
		DL_UNLOAD(extension->handle);
	}
#endif
}


static void zend_extension_message_dispatcher(const zend_extension *extension, int num_args, va_list args)
{
	int message;
	void *arg;

	if (!extension->message_handler || num_args!=2) {
		return;
	}
	message = va_arg(args, int);
	arg = va_arg(args, void *);
	extension->message_handler(message, arg);
}


ZEND_API void zend_extension_dispatch_message(int message, void *arg)
{
	zend_llist_apply_with_arguments(&zend_extensions, (llist_apply_with_args_func_t) zend_extension_message_dispatcher, 2, message, arg);
}


ZEND_API int zend_get_resource_handle(const char *module_name)
{
	if (last_resource_number<ZEND_MAX_RESERVED_RESOURCES) {
		zend_add_system_entropy(module_name, "zend_get_resource_handle", &last_resource_number, sizeof(int));
		return last_resource_number++;
	} else {
		return -1;
	}
}

/**
 * The handle returned by this function can be used with
 * `ZEND_OP_ARRAY_EXTENSION(op_array, handle)`.
 *
 * The extension slot has been available since PHP 7.4 on user functions and
 * has been available since PHP 8.2 on internal functions.
 *
 * # Safety
 * The extension slot made available by calling this function is initialized on
 * the first call made to the function in that request. If you need to
 * initialize it before this point, call `zend_init_func_run_time_cache`.
 *
 * The function cache slots are not available if the function is a trampoline,
 * which can be checked with something like:
 *
 *     if (fbc->type == ZEND_USER_FUNCTION
 *         && !(fbc->op_array.fn_flags & ZEND_ACC_CALL_VIA_TRAMPOLINE)
 *     ) {
 *         // Use ZEND_OP_ARRAY_EXTENSION somehow
 *     }
 */
ZEND_API int zend_get_op_array_extension_handle(const char *module_name)
{
	int handle = zend_op_array_extension_handles++;
	zend_add_system_entropy(module_name, "zend_get_op_array_extension_handle", &zend_op_array_extension_handles, sizeof(int));
	return handle;
}

/** See zend_get_op_array_extension_handle for important usage information. */
ZEND_API int zend_get_op_array_extension_handles(const char *module_name, int handles)
{
	int handle = zend_op_array_extension_handles;
	zend_op_array_extension_handles += handles;
	zend_add_system_entropy(module_name, "zend_get_op_array_extension_handle", &zend_op_array_extension_handles, sizeof(int));
	return handle;
}

ZEND_API int zend_get_internal_function_extension_handle(const char *module_name)
{
	int handle = zend_internal_function_extension_handles++;
	zend_add_system_entropy(module_name, "zend_get_internal_function_extension_handle", &zend_internal_function_extension_handles, sizeof(int));
	return handle;
}

ZEND_API int zend_get_internal_function_extension_handles(const char *module_name, int handles)
{
	int handle = zend_internal_function_extension_handles;
	zend_internal_function_extension_handles += handles;
	zend_add_system_entropy(module_name, "zend_get_internal_function_extension_handle", &zend_internal_function_extension_handles, sizeof(int));
	return handle;
}

ZEND_API size_t zend_internal_run_time_cache_reserved_size(void) {
	return zend_internal_function_extension_handles * sizeof(void *);
}

ZEND_API void zend_init_internal_run_time_cache(void) {
	size_t rt_size = zend_internal_run_time_cache_reserved_size();
	if (rt_size) {
		size_t functions = zend_hash_num_elements(CG(function_table));
		zend_class_entry *ce;
		ZEND_HASH_MAP_FOREACH_PTR(CG(class_table), ce) {
			functions += zend_hash_num_elements(&ce->function_table);
		} ZEND_HASH_FOREACH_END();

		size_t alloc_size = functions * rt_size;
		char *ptr = pemalloc(alloc_size, 1);

		CG(internal_run_time_cache) = ptr;
		CG(internal_run_time_cache_size) = alloc_size;

		zend_internal_function *zif;
		ZEND_HASH_MAP_FOREACH_PTR(CG(function_table), zif) {
			if (!ZEND_USER_CODE(zif->type) && ZEND_MAP_PTR_GET(zif->run_time_cache) == NULL) {
				ZEND_MAP_PTR_SET(zif->run_time_cache, (void *)ptr);
				ptr += rt_size;
			}
		} ZEND_HASH_FOREACH_END();
		ZEND_HASH_MAP_FOREACH_PTR(CG(class_table), ce) {
			ZEND_HASH_MAP_FOREACH_PTR(&ce->function_table, zif) {
				if (!ZEND_USER_CODE(zif->type) && ZEND_MAP_PTR_GET(zif->run_time_cache) == NULL) {
					ZEND_MAP_PTR_SET(zif->run_time_cache, (void *)ptr);
					ptr += rt_size;
				}
			} ZEND_HASH_FOREACH_END();
		} ZEND_HASH_FOREACH_END();
	}
}

ZEND_API void zend_reset_internal_run_time_cache(void) {
	if (CG(internal_run_time_cache)) {
		memset(CG(internal_run_time_cache), 0, CG(internal_run_time_cache_size));
	}
}

ZEND_API zend_extension *zend_get_extension(const char *extension_name)
{
	zend_llist_element *element;

	for (element = zend_extensions.head; element; element = element->next) {
		zend_extension *extension = (zend_extension *) element->data;

		if (!strcmp(extension->name, extension_name)) {
			return extension;
		}
	}
	return NULL;
}

typedef struct _zend_extension_persist_data {
	zend_op_array *op_array;
	size_t         size;
	char          *mem;
} zend_extension_persist_data;

static void zend_extension_op_array_persist_calc_handler(zend_extension *extension, zend_extension_persist_data *data)
{
	if (extension->op_array_persist_calc) {
		data->size += extension->op_array_persist_calc(data->op_array);
	}
}

static void zend_extension_op_array_persist_handler(zend_extension *extension, zend_extension_persist_data *data)
{
	if (extension->op_array_persist) {
		size_t size = extension->op_array_persist(data->op_array, data->mem);
		if (size) {
			data->mem = (void*)((char*)data->mem + size);
			data->size += size;
		}
	}
}

ZEND_API size_t zend_extensions_op_array_persist_calc(zend_op_array *op_array)
{
	if (zend_extension_flags & ZEND_EXTENSIONS_HAVE_OP_ARRAY_PERSIST_CALC) {
		zend_extension_persist_data data;

		data.op_array = op_array;
		data.size = 0;
		data.mem  = NULL;
		zend_llist_apply_with_argument(&zend_extensions, (llist_apply_with_arg_func_t) zend_extension_op_array_persist_calc_handler, &data);
		return data.size;
	}
	return 0;
}

ZEND_API size_t zend_extensions_op_array_persist(zend_op_array *op_array, void *mem)
{
	if (zend_extension_flags & ZEND_EXTENSIONS_HAVE_OP_ARRAY_PERSIST) {
		zend_extension_persist_data data;

		data.op_array = op_array;
		data.size = 0;
		data.mem  = mem;
		zend_llist_apply_with_argument(&zend_extensions, (llist_apply_with_arg_func_t) zend_extension_op_array_persist_handler, &data);
		return data.size;
	}
	return 0;
}
