php-src/Zend/zend_fibers.c

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/*
+----------------------------------------------------------------------+
| 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 |
| license@zend.com so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: Aaron Piotrowski <aaron@trowski.com> |
| Martin Schröder <m.schroeder2007@gmail.com> |
+----------------------------------------------------------------------+
*/
#include "zend.h"
#include "zend_API.h"
#include "zend_ini.h"
#include "zend_vm.h"
#include "zend_interfaces.h"
#include "zend_exceptions.h"
#include "zend_builtin_functions.h"
#include "zend_observer.h"
#include "zend_fibers.h"
#include "zend_fibers_arginfo.h"
#ifdef HAVE_VALGRIND
# include <valgrind/valgrind.h>
#endif
#ifndef ZEND_WIN32
# include <unistd.h>
# include <sys/mman.h>
# include <limits.h>
# if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
# define MAP_ANONYMOUS MAP_ANON
# endif
/* FreeBSD require a first (i.e. addr) argument of mmap(2) is not NULL
* if MAP_STACK is passed.
* http://www.FreeBSD.org/cgi/query-pr.cgi?pr=158755 */
# if !defined(MAP_STACK) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
# undef MAP_STACK
# define MAP_STACK 0
# endif
# ifndef MAP_FAILED
# define MAP_FAILED ((void * ) -1)
# endif
#endif
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#ifdef __SANITIZE_ADDRESS__
# include <sanitizer/common_interface_defs.h>
#endif
ZEND_API zend_class_entry *zend_ce_fiber;
static zend_class_entry *zend_ce_fiber_error;
static zend_object_handlers zend_fiber_handlers;
static zend_function zend_fiber_function = { ZEND_INTERNAL_FUNCTION };
typedef void *fcontext_t;
typedef struct _transfer_t {
fcontext_t context;
void *data;
} transfer_t;
extern fcontext_t make_fcontext(void *sp, size_t size, void (*fn)(transfer_t));
extern transfer_t jump_fcontext(fcontext_t to, void *vp);
#define ZEND_FIBER_DEFAULT_PAGE_SIZE 4096
static size_t zend_fiber_get_page_size(void)
{
static size_t page_size = 0;
if (!page_size) {
page_size = zend_get_page_size();
if (!page_size || (page_size & (page_size - 1))) {
/* anyway, we have to return a valid result */
page_size = ZEND_FIBER_DEFAULT_PAGE_SIZE;
}
}
return page_size;
}
static bool zend_fiber_stack_allocate(zend_fiber_stack *stack, size_t size)
{
void *pointer;
const size_t page_size = zend_fiber_get_page_size();
ZEND_ASSERT(size >= page_size + ZEND_FIBER_GUARD_PAGES * page_size);
stack->size = (size + page_size - 1) / page_size * page_size;
const size_t msize = stack->size + ZEND_FIBER_GUARD_PAGES * page_size;
#ifdef ZEND_WIN32
pointer = VirtualAlloc(0, msize, MEM_COMMIT, PAGE_READWRITE);
if (!pointer) {
DWORD err = GetLastError();
char *errmsg = php_win32_error_to_msg(err);
zend_throw_exception_ex(NULL, 0, "Fiber make context failed: VirtualAlloc failed: [0x%08lx] %s", err, errmsg[0] ? errmsg : "Unknown");
php_win32_error_msg_free(errmsg);
return false;
}
# if ZEND_FIBER_GUARD_PAGES
DWORD protect;
if (!VirtualProtect(pointer, ZEND_FIBER_GUARD_PAGES * page_size, PAGE_READWRITE | PAGE_GUARD, &protect)) {
DWORD err = GetLastError();
char *errmsg = php_win32_error_to_msg(err);
zend_throw_exception_ex(NULL, 0, "Fiber protect stack failed: VirtualProtect failed: [0x%08lx] %s", err, errmsg[0] ? errmsg : "Unknown");
php_win32_error_msg_free(errmsg);
VirtualFree(pointer, 0, MEM_RELEASE);
return false;
}
# endif
#else
pointer = mmap(NULL, msize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
if (pointer == MAP_FAILED) {
zend_throw_exception_ex(NULL, 0, "Fiber make context failed: mmap failed: %s (%d)", strerror(errno), errno);
return false;
}
# if ZEND_FIBER_GUARD_PAGES
if (mprotect(pointer, ZEND_FIBER_GUARD_PAGES * page_size, PROT_NONE) < 0) {
zend_throw_exception_ex(NULL, 0, "Fiber protect stack failed: mmap failed: %s (%d)", strerror(errno), errno);
munmap(pointer, msize);
return false;
}
# endif
#endif
stack->pointer = (void *) ((uintptr_t) pointer + ZEND_FIBER_GUARD_PAGES * page_size);
#ifdef VALGRIND_STACK_REGISTER
uintptr_t base = (uintptr_t) stack->pointer;
stack->valgrind = VALGRIND_STACK_REGISTER(base, base + stack->size);
#endif
#ifdef __SANITIZE_ADDRESS__
stack->prior_pointer = stack->pointer;
stack->prior_size = stack->size;
#endif
return true;
}
static void zend_fiber_stack_free(zend_fiber_stack *stack)
{
if (!stack->pointer) {
return;
}
#ifdef VALGRIND_STACK_DEREGISTER
VALGRIND_STACK_DEREGISTER(stack->valgrind);
#endif
const size_t page_size = zend_fiber_get_page_size();
void *pointer = (void *) ((uintptr_t) stack->pointer - ZEND_FIBER_GUARD_PAGES * page_size);
#ifdef ZEND_WIN32
VirtualFree(pointer, 0, MEM_RELEASE);
#else
munmap(pointer, stack->size + ZEND_FIBER_GUARD_PAGES * page_size);
#endif
stack->pointer = NULL;
}
static ZEND_NORETURN void zend_fiber_trampoline(transfer_t transfer)
{
zend_fiber_context *context = EG(current_fiber);
zend_fiber_context *from = transfer.data;
from->handle = transfer.context;
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#ifdef __SANITIZE_ADDRESS__
__sanitizer_finish_switch_fiber(NULL, &from->stack.prior_pointer, &from->stack.prior_size);
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#endif
/* Final context switch, the fiber must not be resumed afterwards! */
zend_fiber_switch_context(context->function(context));
/* Abort here because we are in an inconsistent program state. */
abort();
}
ZEND_API bool zend_fiber_init_context(zend_fiber_context *context, zend_fiber_coroutine coroutine, size_t stack_size)
{
if (UNEXPECTED(!zend_fiber_stack_allocate(&context->stack, stack_size))) {
return false;
}
// Stack grows down, calculate the top of the stack. make_fcontext then shifts pointer to lower 16-byte boundary.
void *stack = (void *) ((uintptr_t) context->stack.pointer + context->stack.size);
context->handle = make_fcontext(stack, context->stack.size, zend_fiber_trampoline);
ZEND_ASSERT(context->handle != NULL && "make_fcontext() never returns NULL");
context->function = coroutine;
return true;
}
ZEND_API void zend_fiber_destroy_context(zend_fiber_context *context)
{
zend_fiber_stack_free(&context->stack);
}
ZEND_API void zend_fiber_switch_context(zend_fiber_context *to)
{
zend_fiber_context *from = EG(current_fiber);
ZEND_ASSERT(to && to->handle && "Invalid fiber context");
ZEND_ASSERT(from && "From fiber context must be present");
ZEND_ASSERT(to != from && "Cannot switch into the running fiber context");
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#ifdef __SANITIZE_ADDRESS__
void *fake_stack = NULL;
__sanitizer_start_switch_fiber(
from->status != ZEND_FIBER_STATUS_DEAD ? &fake_stack : NULL,
to->stack.prior_pointer,
to->stack.prior_size);
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#endif
EG(current_fiber) = to;
transfer_t transfer = jump_fcontext(to->handle, from);
((zend_fiber_context *) transfer.data)->handle = transfer.context;
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EG(current_fiber) = from;
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#ifdef __SANITIZE_ADDRESS__
__sanitizer_finish_switch_fiber(fake_stack, &to->stack.prior_pointer, &to->stack.prior_size);
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#endif
}
static void zend_fiber_suspend_from(zend_fiber *fiber)
{
zend_fiber_vm_state state;
ZEND_ASSERT(fiber->caller && "Fiber has no caller");
zend_fiber_capture_vm_state(&state);
zend_fiber_switch_context(zend_fiber_get_context(fiber->caller));
zend_fiber_restore_vm_state(&state);
}
static void zend_fiber_switch_to(zend_fiber *fiber)
{
zend_fiber_context *context = zend_fiber_get_context(fiber);
zend_fiber_vm_state state;
zend_observer_fiber_switch_notify(EG(current_fiber), context);
fiber->caller = zend_fiber_from_context(EG(current_fiber));
zend_fiber_capture_vm_state(&state);
zend_fiber_switch_context(context);
zend_fiber_restore_vm_state(&state);
fiber->caller = NULL;
zend_observer_fiber_switch_notify(context, EG(current_fiber));
if (UNEXPECTED(fiber->flags & ZEND_FIBER_FLAG_BAILOUT)) {
// zend_bailout() was called in the fiber, so call it again in the previous fiber or {main}.
zend_bailout();
}
}
static zend_always_inline zend_vm_stack zend_fiber_vm_stack_alloc(size_t size)
{
zend_vm_stack page = emalloc(size);
page->top = ZEND_VM_STACK_ELEMENTS(page);
page->end = (zval *) ((uintptr_t) page + size);
page->prev = NULL;
return page;
}
static ZEND_STACK_ALIGNED zend_fiber_context *zend_fiber_execute(zend_fiber_context *context)
{
zend_fiber *fiber = zend_fiber_from_context(context);
zend_long error_reporting = INI_INT("error_reporting");
if (!error_reporting && !INI_STR("error_reporting")) {
error_reporting = E_ALL;
}
EG(vm_stack) = NULL;
zend_first_try {
zend_vm_stack stack = zend_fiber_vm_stack_alloc(ZEND_FIBER_VM_STACK_SIZE);
EG(vm_stack) = stack;
EG(vm_stack_top) = stack->top + ZEND_CALL_FRAME_SLOT;
EG(vm_stack_end) = stack->end;
EG(vm_stack_page_size) = ZEND_FIBER_VM_STACK_SIZE;
fiber->execute_data = (zend_execute_data *) stack->top;
fiber->stack_bottom = fiber->execute_data;
memset(fiber->execute_data, 0, sizeof(zend_execute_data));
fiber->execute_data->func = &zend_fiber_function;
fiber->stack_bottom->prev_execute_data = EG(current_execute_data);
EG(current_execute_data) = fiber->execute_data;
EG(jit_trace_num) = 0;
EG(error_reporting) = error_reporting;
fiber->fci.retval = &fiber->value;
fiber->status = ZEND_FIBER_STATUS_RUNNING;
zend_call_function(&fiber->fci, &fiber->fci_cache);
zval_ptr_dtor(&fiber->fci.function_name);
if (EG(exception)) {
if (fiber->flags & ZEND_FIBER_FLAG_DESTROYED) {
if (EXPECTED(zend_is_graceful_exit(EG(exception)) || zend_is_unwind_exit(EG(exception)))) {
zend_clear_exception();
}
} else {
fiber->flags = ZEND_FIBER_FLAG_THREW;
}
}
} zend_catch {
fiber->flags |= ZEND_FIBER_FLAG_BAILOUT;
} zend_end_try();
fiber->status = ZEND_FIBER_STATUS_DEAD;
zend_vm_stack_destroy();
fiber->execute_data = NULL;
fiber->stack_bottom = NULL;
return zend_fiber_get_context(fiber->caller);
}
static zend_object *zend_fiber_object_create(zend_class_entry *ce)
{
zend_fiber *fiber;
fiber = emalloc(sizeof(zend_fiber));
memset(fiber, 0, sizeof(zend_fiber));
zend_object_std_init(&fiber->std, ce);
fiber->std.handlers = &zend_fiber_handlers;
return &fiber->std;
}
static void zend_fiber_object_destroy(zend_object *object)
{
zend_fiber *fiber = (zend_fiber *) object;
if (fiber->status != ZEND_FIBER_STATUS_SUSPENDED) {
return;
}
zend_object *exception = EG(exception);
EG(exception) = NULL;
fiber->status = ZEND_FIBER_STATUS_RUNNING;
fiber->flags |= ZEND_FIBER_FLAG_DESTROYED;
zend_fiber_switch_to(fiber);
if (EG(exception)) {
if (!exception && EG(current_execute_data) && EG(current_execute_data)->func
&& ZEND_USER_CODE(EG(current_execute_data)->func->common.type)) {
zend_rethrow_exception(EG(current_execute_data));
}
zend_exception_set_previous(EG(exception), exception);
if (!EG(current_execute_data)) {
zend_exception_error(EG(exception), E_ERROR);
}
} else {
EG(exception) = exception;
}
}
static void zend_fiber_object_free(zend_object *object)
{
zend_fiber *fiber = (zend_fiber *) object;
if (fiber->status == ZEND_FIBER_STATUS_INIT) {
// Fiber was never started, so we need to release the reference to the callback.
zval_ptr_dtor(&fiber->fci.function_name);
}
zval_ptr_dtor(&fiber->value);
zend_fiber_destroy_context(zend_fiber_get_context(fiber));
zend_object_std_dtor(&fiber->std);
}
ZEND_API zend_fiber *zend_fiber_create(const zend_fcall_info *fci, const zend_fcall_info_cache *fci_cache)
{
zend_fiber *fiber = (zend_fiber *) zend_fiber_object_create(zend_ce_fiber);
fiber->fci = *fci;
fiber->fci_cache = *fci_cache;
Z_TRY_ADDREF(fiber->fci.function_name);
return fiber;
}
ZEND_METHOD(Fiber, __construct)
{
zend_fiber *fiber = (zend_fiber *) Z_OBJ_P(getThis());
ZEND_PARSE_PARAMETERS_START(1, 1)
Z_PARAM_FUNC(fiber->fci, fiber->fci_cache)
ZEND_PARSE_PARAMETERS_END();
// Keep a reference to closures or callable objects while the fiber is running.
Z_TRY_ADDREF(fiber->fci.function_name);
}
ZEND_API void zend_fiber_start(zend_fiber *fiber, zval *params, uint32_t param_count, zend_array *named_params, zval *return_value)
{
if (fiber->status != ZEND_FIBER_STATUS_INIT) {
zend_throw_error(zend_ce_fiber_error, "Cannot start a fiber that has already been started");
RETURN_THROWS();
}
fiber->fci.params = params;
fiber->fci.param_count = param_count;
fiber->fci.named_params = named_params;
if (!zend_fiber_init_context(zend_fiber_get_context(fiber), zend_fiber_execute, EG(fiber_stack_size))) {
RETURN_THROWS();
}
zend_fiber_switch_to(fiber);
if (fiber->status == ZEND_FIBER_STATUS_DEAD) {
RETURN_NULL();
}
RETVAL_COPY_VALUE(&fiber->value);
ZVAL_UNDEF(&fiber->value);
}
ZEND_METHOD(Fiber, start)
{
zend_fiber *fiber = (zend_fiber *) Z_OBJ_P(getThis());
zval *params;
uint32_t param_count;
zend_array *named_params;
ZEND_PARSE_PARAMETERS_START(0, -1)
Z_PARAM_VARIADIC_WITH_NAMED(params, param_count, named_params);
ZEND_PARSE_PARAMETERS_END();
zend_fiber_start(fiber, params, param_count, named_params, return_value);
}
ZEND_API void zend_fiber_suspend(zval *value, zval *return_value)
{
if (UNEXPECTED(EG(current_fiber) == EG(main_fiber))) {
zend_throw_error(zend_ce_fiber_error, "Cannot suspend outside of a fiber");
RETURN_THROWS();
}
zend_fiber *fiber = zend_fiber_from_context(EG(current_fiber));
if (UNEXPECTED(fiber->flags & ZEND_FIBER_FLAG_DESTROYED)) {
zend_throw_error(zend_ce_fiber_error, "Cannot suspend in a force-closed fiber");
RETURN_THROWS();
}
ZEND_ASSERT(fiber->status == ZEND_FIBER_STATUS_RUNNING);
if (value) {
ZVAL_COPY(&fiber->value, value);
} else {
ZVAL_NULL(&fiber->value);
}
fiber->execute_data = EG(current_execute_data);
fiber->status = ZEND_FIBER_STATUS_SUSPENDED;
fiber->stack_bottom->prev_execute_data = NULL;
zend_fiber_suspend_from(fiber);
if (fiber->flags & ZEND_FIBER_FLAG_DESTROYED) {
// This occurs when the fiber is GC'ed while suspended.
zend_throw_graceful_exit();
RETURN_THROWS();
}
fiber->status = ZEND_FIBER_STATUS_RUNNING;
if (fiber->exception) {
zval *exception = fiber->exception;
fiber->exception = NULL;
zend_throw_exception_object(exception);
RETURN_THROWS();
}
RETVAL_COPY_VALUE(&fiber->value);
ZVAL_UNDEF(&fiber->value);
}
ZEND_METHOD(Fiber, suspend)
{
zval *value = NULL;
ZEND_PARSE_PARAMETERS_START(0, 1)
Z_PARAM_OPTIONAL
Z_PARAM_ZVAL(value);
ZEND_PARSE_PARAMETERS_END();
zend_fiber_suspend(value, return_value);
}
ZEND_API void zend_fiber_resume(zend_fiber *fiber, zval *value, zval *return_value)
{
if (UNEXPECTED(fiber->status != ZEND_FIBER_STATUS_SUSPENDED)) {
zend_throw_error(zend_ce_fiber_error, "Cannot resume a fiber that is not suspended");
RETURN_THROWS();
}
if (value) {
ZVAL_COPY(&fiber->value, value);
} else {
ZVAL_NULL(&fiber->value);
}
fiber->status = ZEND_FIBER_STATUS_RUNNING;
fiber->stack_bottom->prev_execute_data = EG(current_execute_data);
zend_fiber_switch_to(fiber);
if (fiber->status == ZEND_FIBER_STATUS_DEAD) {
RETURN_NULL();
}
RETVAL_COPY_VALUE(&fiber->value);
ZVAL_UNDEF(&fiber->value);
}
ZEND_METHOD(Fiber, resume)
{
zend_fiber *fiber;
zval *value = NULL;
ZEND_PARSE_PARAMETERS_START(0, 1)
Z_PARAM_OPTIONAL
Z_PARAM_ZVAL(value);
ZEND_PARSE_PARAMETERS_END();
fiber = (zend_fiber *) Z_OBJ_P(getThis());
zend_fiber_resume(fiber, value, return_value);
}
ZEND_API void zend_fiber_throw(zend_fiber *fiber, zval *exception, zval *return_value)
{
if (UNEXPECTED(fiber->status != ZEND_FIBER_STATUS_SUSPENDED)) {
zend_throw_error(zend_ce_fiber_error, "Cannot resume a fiber that is not suspended");
RETURN_THROWS();
}
Z_ADDREF_P(exception);
fiber->exception = exception;
fiber->status = ZEND_FIBER_STATUS_RUNNING;
fiber->stack_bottom->prev_execute_data = EG(current_execute_data);
zend_fiber_switch_to(fiber);
if (fiber->status == ZEND_FIBER_STATUS_DEAD) {
RETURN_NULL();
}
RETVAL_COPY_VALUE(&fiber->value);
ZVAL_UNDEF(&fiber->value);
}
ZEND_METHOD(Fiber, throw)
{
zend_fiber *fiber;
zval *exception;
ZEND_PARSE_PARAMETERS_START(1, 1)
Z_PARAM_OBJECT_OF_CLASS(exception, zend_ce_throwable)
ZEND_PARSE_PARAMETERS_END();
fiber = (zend_fiber *) Z_OBJ_P(getThis());
zend_fiber_throw(fiber, exception, return_value);
}
ZEND_METHOD(Fiber, isStarted)
{
zend_fiber *fiber;
ZEND_PARSE_PARAMETERS_NONE();
fiber = (zend_fiber *) Z_OBJ_P(getThis());
RETURN_BOOL(fiber->status != ZEND_FIBER_STATUS_INIT);
}
ZEND_METHOD(Fiber, isSuspended)
{
zend_fiber *fiber;
ZEND_PARSE_PARAMETERS_NONE();
fiber = (zend_fiber *) Z_OBJ_P(getThis());
RETURN_BOOL(fiber->status == ZEND_FIBER_STATUS_SUSPENDED);
}
ZEND_METHOD(Fiber, isRunning)
{
zend_fiber *fiber;
ZEND_PARSE_PARAMETERS_NONE();
fiber = (zend_fiber *) Z_OBJ_P(getThis());
RETURN_BOOL(fiber->status == ZEND_FIBER_STATUS_RUNNING);
}
ZEND_METHOD(Fiber, isTerminated)
{
zend_fiber *fiber;
ZEND_PARSE_PARAMETERS_NONE();
fiber = (zend_fiber *) Z_OBJ_P(getThis());
RETURN_BOOL(fiber->status == ZEND_FIBER_STATUS_DEAD);
}
ZEND_METHOD(Fiber, getReturn)
{
zend_fiber *fiber;
const char *message;
ZEND_PARSE_PARAMETERS_NONE();
fiber = (zend_fiber *) Z_OBJ_P(getThis());
if (fiber->status == ZEND_FIBER_STATUS_DEAD) {
if (fiber->flags & ZEND_FIBER_FLAG_THREW) {
message = "The fiber threw an exception";
} else {
RETURN_COPY(&fiber->value);
}
} else if (fiber->status == ZEND_FIBER_STATUS_INIT) {
message = "The fiber has not been started";
} else {
message = "The fiber has not returned";
}
zend_throw_error(zend_ce_fiber_error, "Cannot get fiber return value: %s", message);
RETURN_THROWS();
}
ZEND_METHOD(Fiber, this)
{
ZEND_PARSE_PARAMETERS_NONE();
if (EG(current_fiber) == EG(main_fiber)) {
RETURN_NULL();
}
RETURN_OBJ_COPY(&zend_fiber_from_context(EG(current_fiber))->std);
}
ZEND_METHOD(FiberError, __construct)
{
zend_throw_error(
NULL,
"The \"%s\" class is reserved for internal use and cannot be manually instantiated",
ZSTR_VAL(Z_OBJCE_P(getThis())->name)
);
}
void zend_register_fiber_ce(void)
{
zend_ce_fiber = register_class_Fiber();
zend_ce_fiber->create_object = zend_fiber_object_create;
zend_ce_fiber->serialize = zend_class_serialize_deny;
zend_ce_fiber->unserialize = zend_class_unserialize_deny;
zend_fiber_handlers = std_object_handlers;
zend_fiber_handlers.dtor_obj = zend_fiber_object_destroy;
zend_fiber_handlers.free_obj = zend_fiber_object_free;
zend_fiber_handlers.clone_obj = NULL;
zend_ce_fiber_error = register_class_FiberError(zend_ce_error);
zend_ce_fiber_error->create_object = zend_ce_error->create_object;
}
void zend_fiber_init(void)
{
zend_fiber_context *context = ecalloc(1, sizeof(zend_fiber_context));
context->status = ZEND_FIBER_STATUS_RUNNING;
EG(main_fiber) = context;
EG(current_fiber) = context;
}
void zend_fiber_shutdown(void)
{
efree(EG(main_fiber));
}