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40760d12ba
darling-objc4/runtime/objc-os.mm
Ariel Abreu 4d6225bbe3
objc4-781.2
2020-06-09 21:50:17 -04:00

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/*
* Copyright (c) 2007 Apple Inc. All Rights Reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/***********************************************************************
* objc-os.m
* OS portability layer.
**********************************************************************/
#include "objc-private.h"
#include "objc-loadmethod.h"
#include "objc-cache.h"
#if TARGET_OS_WIN32
#include "objc-runtime-old.h"
#include "objcrt.h"
const fork_unsafe_lock_t fork_unsafe_lock;
int monitor_init(monitor_t *c)
{
// fixme error checking
HANDLE mutex = CreateMutex(NULL, TRUE, NULL);
while (!c->mutex) {
// fixme memory barrier here?
if (0 == InterlockedCompareExchangePointer(&c->mutex, mutex, 0)) {
// we win - finish construction
c->waiters = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
c->waitersDone = CreateEvent(NULL, FALSE, FALSE, NULL);
InitializeCriticalSection(&c->waitCountLock);
c->waitCount = 0;
c->didBroadcast = 0;
ReleaseMutex(c->mutex);
return 0;
}
}
// someone else allocated the mutex and constructed the monitor
ReleaseMutex(mutex);
CloseHandle(mutex);
return 0;
}
void mutex_init(mutex_t *m)
{
while (!m->lock) {
CRITICAL_SECTION *newlock = malloc(sizeof(CRITICAL_SECTION));
InitializeCriticalSection(newlock);
// fixme memory barrier here?
if (0 == InterlockedCompareExchangePointer(&m->lock, newlock, 0)) {
return;
}
// someone else installed their lock first
DeleteCriticalSection(newlock);
free(newlock);
}
}
void recursive_mutex_init(recursive_mutex_t *m)
{
// fixme error checking
HANDLE newmutex = CreateMutex(NULL, FALSE, NULL);
while (!m->mutex) {
// fixme memory barrier here?
if (0 == InterlockedCompareExchangePointer(&m->mutex, newmutex, 0)) {
// we win
return;
}
}
// someone else installed their lock first
CloseHandle(newmutex);
}
WINBOOL APIENTRY DllMain( HMODULE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
switch (ul_reason_for_call) {
case DLL_PROCESS_ATTACH:
environ_init();
tls_init();
runtime_init();
sel_init(3500); // old selector heuristic
exception_init();
break;
case DLL_THREAD_ATTACH:
break;
case DLL_THREAD_DETACH:
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}
OBJC_EXPORT void *_objc_init_image(HMODULE image, const objc_sections *sects)
{
header_info *hi = malloc(sizeof(header_info));
size_t count, i;
hi->mhdr = (const headerType *)image;
hi->info = sects->iiStart;
hi->allClassesRealized = NO;
hi->modules = sects->modStart ? (Module *)((void **)sects->modStart+1) : 0;
hi->moduleCount = (Module *)sects->modEnd - hi->modules;
hi->protocols = sects->protoStart ? (struct old_protocol **)((void **)sects->protoStart+1) : 0;
hi->protocolCount = (struct old_protocol **)sects->protoEnd - hi->protocols;
hi->imageinfo = NULL;
hi->imageinfoBytes = 0;
// hi->imageinfo = sects->iiStart ? (uint8_t *)((void **)sects->iiStart+1) : 0;;
// hi->imageinfoBytes = (uint8_t *)sects->iiEnd - hi->imageinfo;
hi->selrefs = sects->selrefsStart ? (SEL *)((void **)sects->selrefsStart+1) : 0;
hi->selrefCount = (SEL *)sects->selrefsEnd - hi->selrefs;
hi->clsrefs = sects->clsrefsStart ? (Class *)((void **)sects->clsrefsStart+1) : 0;
hi->clsrefCount = (Class *)sects->clsrefsEnd - hi->clsrefs;
count = 0;
for (i = 0; i < hi->moduleCount; i++) {
if (hi->modules[i]) count++;
}
hi->mod_count = 0;
hi->mod_ptr = 0;
if (count > 0) {
hi->mod_ptr = malloc(count * sizeof(struct objc_module));
for (i = 0; i < hi->moduleCount; i++) {
if (hi->modules[i]) memcpy(&hi->mod_ptr[hi->mod_count++], hi->modules[i], sizeof(struct objc_module));
}
}
hi->moduleName = malloc(MAX_PATH * sizeof(TCHAR));
GetModuleFileName((HMODULE)(hi->mhdr), hi->moduleName, MAX_PATH * sizeof(TCHAR));
appendHeader(hi);
if (PrintImages) {
_objc_inform("IMAGES: loading image for %s%s%s%s\n",
hi->fname,
headerIsBundle(hi) ? " (bundle)" : "",
hi->info->isReplacement() ? " (replacement)":"",
hi->info->hasCategoryClassProperties() ? " (has class properties)":"");
}
// Count classes. Size various table based on the total.
int total = 0;
int unoptimizedTotal = 0;
{
if (_getObjc2ClassList(hi, &count)) {
total += (int)count;
if (!hi->getInSharedCache()) unoptimizedTotal += count;
}
}
_read_images(&hi, 1, total, unoptimizedTotal);
return hi;
}
OBJC_EXPORT void _objc_load_image(HMODULE image, header_info *hinfo)
{
prepare_load_methods(hinfo);
call_load_methods();
}
OBJC_EXPORT void _objc_unload_image(HMODULE image, header_info *hinfo)
{
_objc_fatal("image unload not supported");
}
// TARGET_OS_WIN32
#elif TARGET_OS_MAC
#include "objc-file-old.h"
#include "objc-file.h"
/***********************************************************************
* libobjc must never run static destructors.
* Cover libc's __cxa_atexit with our own definition that runs nothing.
* rdar://21734598 ER: Compiler option to suppress C++ static destructors
**********************************************************************/
extern "C" int __cxa_atexit();
extern "C" int __cxa_atexit() { return 0; }
/***********************************************************************
* bad_magic.
* Return YES if the header has invalid Mach-o magic.
**********************************************************************/
bool bad_magic(const headerType *mhdr)
{
return (mhdr->magic != MH_MAGIC && mhdr->magic != MH_MAGIC_64 &&
mhdr->magic != MH_CIGAM && mhdr->magic != MH_CIGAM_64);
}
static header_info * addHeader(const headerType *mhdr, const char *path, int &totalClasses, int &unoptimizedTotalClasses)
{
header_info *hi;
if (bad_magic(mhdr)) return NULL;
bool inSharedCache = false;
// Look for hinfo from the dyld shared cache.
hi = preoptimizedHinfoForHeader(mhdr);
if (hi) {
// Found an hinfo in the dyld shared cache.
// Weed out duplicates.
if (hi->isLoaded()) {
return NULL;
}
inSharedCache = true;
// Initialize fields not set by the shared cache
// hi->next is set by appendHeader
hi->setLoaded(true);
if (PrintPreopt) {
_objc_inform("PREOPTIMIZATION: honoring preoptimized header info at %p for %s", hi, hi->fname());
}
#if !__OBJC2__
_objc_fatal("shouldn't be here");
#endif
#if DEBUG
// Verify image_info
size_t info_size = 0;
const objc_image_info *image_info = _getObjcImageInfo(mhdr,&info_size);
ASSERT(image_info == hi->info());
#endif
}
else
{
// Didn't find an hinfo in the dyld shared cache.
// Locate the __OBJC segment
size_t info_size = 0;
unsigned long seg_size;
const objc_image_info *image_info = _getObjcImageInfo(mhdr,&info_size);
const uint8_t *objc_segment = getsegmentdata(mhdr,SEG_OBJC,&seg_size);
if (!objc_segment && !image_info) return NULL;
// Allocate a header_info entry.
// Note we also allocate space for a single header_info_rw in the
// rw_data[] inside header_info.
hi = (header_info *)calloc(sizeof(header_info) + sizeof(header_info_rw), 1);
// Set up the new header_info entry.
hi->setmhdr(mhdr);
#if !__OBJC2__
// mhdr must already be set
hi->mod_count = 0;
hi->mod_ptr = _getObjcModules(hi, &hi->mod_count);
#endif
// Install a placeholder image_info if absent to simplify code elsewhere
static const objc_image_info emptyInfo = {0, 0};
hi->setinfo(image_info ?: &emptyInfo);
hi->setLoaded(true);
hi->setAllClassesRealized(NO);
}
#if __OBJC2__
{
size_t count = 0;
if (_getObjc2ClassList(hi, &count)) {
totalClasses += (int)count;
if (!inSharedCache) unoptimizedTotalClasses += count;
}
}
#endif
appendHeader(hi);
return hi;
}
/***********************************************************************
* linksToLibrary
* Returns true if the image links directly to a dylib whose install name
* is exactly the given name.
**********************************************************************/
bool
linksToLibrary(const header_info *hi, const char *name)
{
const struct dylib_command *cmd;
unsigned long i;
cmd = (const struct dylib_command *) (hi->mhdr() + 1);
for (i = 0; i < hi->mhdr()->ncmds; i++) {
if (cmd->cmd == LC_LOAD_DYLIB || cmd->cmd == LC_LOAD_UPWARD_DYLIB ||
cmd->cmd == LC_LOAD_WEAK_DYLIB || cmd->cmd == LC_REEXPORT_DYLIB)
{
const char *dylib = cmd->dylib.name.offset + (const char *)cmd;
if (0 == strcmp(dylib, name)) return true;
}
cmd = (const struct dylib_command *)((char *)cmd + cmd->cmdsize);
}
return false;
}
#if SUPPORT_GC_COMPAT
/***********************************************************************
* shouldRejectGCApp
* Return YES if the executable requires GC.
**********************************************************************/
static bool shouldRejectGCApp(const header_info *hi)
{
ASSERT(hi->mhdr()->filetype == MH_EXECUTE);
if (!hi->info()->supportsGC()) {
// App does not use GC. Don't reject it.
return NO;
}
// Exception: Trivial AppleScriptObjC apps can run without GC.
// 1. executable defines no classes
// 2. executable references NSBundle only
// 3. executable links to AppleScriptObjC.framework
// Note that objc_appRequiresGC() also knows about this.
size_t classcount = 0;
size_t refcount = 0;
#if __OBJC2__
_getObjc2ClassList(hi, &classcount);
_getObjc2ClassRefs(hi, &refcount);
#else
if (hi->mod_count == 0 || (hi->mod_count == 1 && !hi->mod_ptr[0].symtab)) classcount = 0;
else classcount = 1;
_getObjcClassRefs(hi, &refcount);
#endif
if (classcount == 0 && refcount == 1 &&
linksToLibrary(hi, "/System/Library/Frameworks"
"/AppleScriptObjC.framework/Versions/A"
"/AppleScriptObjC"))
{
// It's AppleScriptObjC. Don't reject it.
return NO;
}
else {
// GC and not trivial AppleScriptObjC. Reject it.
return YES;
}
}
/***********************************************************************
* rejectGCImage
* Halt if an image requires GC.
* Testing of the main executable should use rejectGCApp() instead.
**********************************************************************/
static bool shouldRejectGCImage(const headerType *mhdr)
{
ASSERT(mhdr->filetype != MH_EXECUTE);
objc_image_info *image_info;
size_t size;
#if !__OBJC2__
unsigned long seg_size;
// 32-bit: __OBJC seg but no image_info means no GC support
if (!getsegmentdata(mhdr, "__OBJC", &seg_size)) {
// Not objc, therefore not GC. Don't reject it.
return NO;
}
image_info = _getObjcImageInfo(mhdr, &size);
if (!image_info) {
// No image_info, therefore not GC. Don't reject it.
return NO;
}
#else
// 64-bit: no image_info means no objc at all
image_info = _getObjcImageInfo(mhdr, &size);
if (!image_info) {
// Not objc, therefore not GC. Don't reject it.
return NO;
}
#endif
return image_info->requiresGC();
}
// SUPPORT_GC_COMPAT
#endif
// Swift currently adds 4 callbacks.
static GlobalSmallVector<objc_func_loadImage, 4> loadImageFuncs;
void objc_addLoadImageFunc(objc_func_loadImage _Nonnull func) {
// Not supported on the old runtime. Not that the old runtime is supported anyway.
#if __OBJC2__
mutex_locker_t lock(runtimeLock);
// Call it with all the existing images first.
for (auto header = FirstHeader; header; header = header->getNext()) {
func((struct mach_header *)header->mhdr());
}
// Add it to the vector for future loads.
loadImageFuncs.append(func);
#endif
}
/***********************************************************************
* map_images_nolock
* Process the given images which are being mapped in by dyld.
* All class registration and fixups are performed (or deferred pending
* discovery of missing superclasses etc), and +load methods are called.
*
* info[] is in bottom-up order i.e. libobjc will be earlier in the
* array than any library that links to libobjc.
*
* Locking: loadMethodLock(old) or runtimeLock(new) acquired by map_images.
**********************************************************************/
#if __OBJC2__
#include "objc-file.h"
#else
#include "objc-file-old.h"
#endif
void
map_images_nolock(unsigned mhCount, const char * const mhPaths[],
const struct mach_header * const mhdrs[])
{
static bool firstTime = YES;
header_info *hList[mhCount];
uint32_t hCount;
size_t selrefCount = 0;
// Perform first-time initialization if necessary.
// This function is called before ordinary library initializers.
// fixme defer initialization until an objc-using image is found?
if (firstTime) {
preopt_init();
}
if (PrintImages) {
_objc_inform("IMAGES: processing %u newly-mapped images...\n", mhCount);
}
// Find all images with Objective-C metadata.
hCount = 0;
// Count classes. Size various table based on the total.
int totalClasses = 0;
int unoptimizedTotalClasses = 0;
{
uint32_t i = mhCount;
while (i--) {
const headerType *mhdr = (const headerType *)mhdrs[i];
auto hi = addHeader(mhdr, mhPaths[i], totalClasses, unoptimizedTotalClasses);
if (!hi) {
// no objc data in this entry
continue;
}
if (mhdr->filetype == MH_EXECUTE) {
// Size some data structures based on main executable's size
#if __OBJC2__
size_t count;
_getObjc2SelectorRefs(hi, &count);
selrefCount += count;
_getObjc2MessageRefs(hi, &count);
selrefCount += count;
#else
_getObjcSelectorRefs(hi, &selrefCount);
#endif
#if SUPPORT_GC_COMPAT
// Halt if this is a GC app.
if (shouldRejectGCApp(hi)) {
_objc_fatal_with_reason
(OBJC_EXIT_REASON_GC_NOT_SUPPORTED,
OS_REASON_FLAG_CONSISTENT_FAILURE,
"Objective-C garbage collection "
"is no longer supported.");
}
#endif
}
hList[hCount++] = hi;
if (PrintImages) {
_objc_inform("IMAGES: loading image for %s%s%s%s%s\n",
hi->fname(),
mhdr->filetype == MH_BUNDLE ? " (bundle)" : "",
hi->info()->isReplacement() ? " (replacement)" : "",
hi->info()->hasCategoryClassProperties() ? " (has class properties)" : "",
hi->info()->optimizedByDyld()?" (preoptimized)":"");
}
}
}
// Perform one-time runtime initialization that must be deferred until
// the executable itself is found. This needs to be done before
// further initialization.
// (The executable may not be present in this infoList if the
// executable does not contain Objective-C code but Objective-C
// is dynamically loaded later.
if (firstTime) {
sel_init(selrefCount);
arr_init();
#if SUPPORT_GC_COMPAT
// Reject any GC images linked to the main executable.
// We already rejected the app itself above.
// Images loaded after launch will be rejected by dyld.
for (uint32_t i = 0; i < hCount; i++) {
auto hi = hList[i];
auto mh = hi->mhdr();
if (mh->filetype != MH_EXECUTE && shouldRejectGCImage(mh)) {
_objc_fatal_with_reason
(OBJC_EXIT_REASON_GC_NOT_SUPPORTED,
OS_REASON_FLAG_CONSISTENT_FAILURE,
"%s requires Objective-C garbage collection "
"which is no longer supported.", hi->fname());
}
}
#endif
#if TARGET_OS_OSX
// Disable +initialize fork safety if the app is too old (< 10.13).
// Disable +initialize fork safety if the app has a
// __DATA,__objc_fork_ok section.
if (dyld_get_program_sdk_version() < DYLD_MACOSX_VERSION_10_13) {
DisableInitializeForkSafety = true;
if (PrintInitializing) {
_objc_inform("INITIALIZE: disabling +initialize fork "
"safety enforcement because the app is "
"too old (SDK version " SDK_FORMAT ")",
FORMAT_SDK(dyld_get_program_sdk_version()));
}
}
for (uint32_t i = 0; i < hCount; i++) {
auto hi = hList[i];
auto mh = hi->mhdr();
if (mh->filetype != MH_EXECUTE) continue;
unsigned long size;
if (getsectiondata(hi->mhdr(), "__DATA", "__objc_fork_ok", &size)) {
DisableInitializeForkSafety = true;
if (PrintInitializing) {
_objc_inform("INITIALIZE: disabling +initialize fork "
"safety enforcement because the app has "
"a __DATA,__objc_fork_ok section");
}
}
break; // assume only one MH_EXECUTE image
}
#endif
}
if (hCount > 0) {
_read_images(hList, hCount, totalClasses, unoptimizedTotalClasses);
}
firstTime = NO;
// Call image load funcs after everything is set up.
for (auto func : loadImageFuncs) {
for (uint32_t i = 0; i < mhCount; i++) {
func(mhdrs[i]);
}
}
}
/***********************************************************************
* unmap_image_nolock
* Process the given image which is about to be unmapped by dyld.
* mh is mach_header instead of headerType because that's what
* dyld_priv.h says even for 64-bit.
*
* Locking: loadMethodLock(both) and runtimeLock(new) acquired by unmap_image.
**********************************************************************/
void
unmap_image_nolock(const struct mach_header *mh)
{
if (PrintImages) {
_objc_inform("IMAGES: processing 1 newly-unmapped image...\n");
}
header_info *hi;
// Find the runtime's header_info struct for the image
for (hi = FirstHeader; hi != NULL; hi = hi->getNext()) {
if (hi->mhdr() == (const headerType *)mh) {
break;
}
}
if (!hi) return;
if (PrintImages) {
_objc_inform("IMAGES: unloading image for %s%s%s\n",
hi->fname(),
hi->mhdr()->filetype == MH_BUNDLE ? " (bundle)" : "",
hi->info()->isReplacement() ? " (replacement)" : "");
}
_unload_image(hi);
// Remove header_info from header list
removeHeader(hi);
free(hi);
}
/***********************************************************************
* static_init
* Run C++ static constructor functions.
* libc calls _objc_init() before dyld would call our static constructors,
* so we have to do it ourselves.
**********************************************************************/
static void static_init()
{
size_t count;
auto inits = getLibobjcInitializers(&_mh_dylib_header, &count);
for (size_t i = 0; i < count; i++) {
inits[i]();
}
}
/***********************************************************************
* _objc_atfork_prepare
* _objc_atfork_parent
* _objc_atfork_child
* Allow ObjC to be used between fork() and exec().
* libc requires this because it has fork-safe functions that use os_objects.
*
* _objc_atfork_prepare() acquires all locks.
* _objc_atfork_parent() releases the locks again.
* _objc_atfork_child() forcibly resets the locks.
**********************************************************************/
// Declare lock ordering.
#if LOCKDEBUG
__attribute__((constructor))
static void defineLockOrder()
{
// Every lock precedes crashlog_lock
// on the assumption that fatal errors could be anywhere.
lockdebug_lock_precedes_lock(&loadMethodLock, &crashlog_lock);
lockdebug_lock_precedes_lock(&classInitLock, &crashlog_lock);
#if __OBJC2__
lockdebug_lock_precedes_lock(&runtimeLock, &crashlog_lock);
lockdebug_lock_precedes_lock(&DemangleCacheLock, &crashlog_lock);
#else
lockdebug_lock_precedes_lock(&classLock, &crashlog_lock);
lockdebug_lock_precedes_lock(&methodListLock, &crashlog_lock);
lockdebug_lock_precedes_lock(&NXUniqueStringLock, &crashlog_lock);
lockdebug_lock_precedes_lock(&impLock, &crashlog_lock);
#endif
lockdebug_lock_precedes_lock(&selLock, &crashlog_lock);
#if CONFIG_USE_CACHE_LOCK
lockdebug_lock_precedes_lock(&cacheUpdateLock, &crashlog_lock);
#endif
lockdebug_lock_precedes_lock(&objcMsgLogLock, &crashlog_lock);
lockdebug_lock_precedes_lock(&AltHandlerDebugLock, &crashlog_lock);
lockdebug_lock_precedes_lock(&AssociationsManagerLock, &crashlog_lock);
SideTableLocksPrecedeLock(&crashlog_lock);
PropertyLocks.precedeLock(&crashlog_lock);
StructLocks.precedeLock(&crashlog_lock);
CppObjectLocks.precedeLock(&crashlog_lock);
// loadMethodLock precedes everything
// because it is held while +load methods run
lockdebug_lock_precedes_lock(&loadMethodLock, &classInitLock);
#if __OBJC2__
lockdebug_lock_precedes_lock(&loadMethodLock, &runtimeLock);
lockdebug_lock_precedes_lock(&loadMethodLock, &DemangleCacheLock);
#else
lockdebug_lock_precedes_lock(&loadMethodLock, &methodListLock);
lockdebug_lock_precedes_lock(&loadMethodLock, &classLock);
lockdebug_lock_precedes_lock(&loadMethodLock, &NXUniqueStringLock);
lockdebug_lock_precedes_lock(&loadMethodLock, &impLock);
#endif
lockdebug_lock_precedes_lock(&loadMethodLock, &selLock);
#if CONFIG_USE_CACHE_LOCK
lockdebug_lock_precedes_lock(&loadMethodLock, &cacheUpdateLock);
#endif
lockdebug_lock_precedes_lock(&loadMethodLock, &objcMsgLogLock);
lockdebug_lock_precedes_lock(&loadMethodLock, &AltHandlerDebugLock);
lockdebug_lock_precedes_lock(&loadMethodLock, &AssociationsManagerLock);
SideTableLocksSucceedLock(&loadMethodLock);
PropertyLocks.succeedLock(&loadMethodLock);
StructLocks.succeedLock(&loadMethodLock);
CppObjectLocks.succeedLock(&loadMethodLock);
// PropertyLocks and CppObjectLocks and AssociationManagerLock
// precede everything because they are held while objc_retain()
// or C++ copy are called.
// (StructLocks do not precede everything because it calls memmove only.)
auto PropertyAndCppObjectAndAssocLocksPrecedeLock = [&](const void *lock) {
PropertyLocks.precedeLock(lock);
CppObjectLocks.precedeLock(lock);
lockdebug_lock_precedes_lock(&AssociationsManagerLock, lock);
};
#if __OBJC2__
PropertyAndCppObjectAndAssocLocksPrecedeLock(&runtimeLock);
PropertyAndCppObjectAndAssocLocksPrecedeLock(&DemangleCacheLock);
#else
PropertyAndCppObjectAndAssocLocksPrecedeLock(&methodListLock);
PropertyAndCppObjectAndAssocLocksPrecedeLock(&classLock);
PropertyAndCppObjectAndAssocLocksPrecedeLock(&NXUniqueStringLock);
PropertyAndCppObjectAndAssocLocksPrecedeLock(&impLock);
#endif
PropertyAndCppObjectAndAssocLocksPrecedeLock(&classInitLock);
PropertyAndCppObjectAndAssocLocksPrecedeLock(&selLock);
#if CONFIG_USE_CACHE_LOCK
PropertyAndCppObjectAndAssocLocksPrecedeLock(&cacheUpdateLock);
#endif
PropertyAndCppObjectAndAssocLocksPrecedeLock(&objcMsgLogLock);
PropertyAndCppObjectAndAssocLocksPrecedeLock(&AltHandlerDebugLock);
SideTableLocksSucceedLocks(PropertyLocks);
SideTableLocksSucceedLocks(CppObjectLocks);
SideTableLocksSucceedLock(&AssociationsManagerLock);
PropertyLocks.precedeLock(&AssociationsManagerLock);
CppObjectLocks.precedeLock(&AssociationsManagerLock);
#if __OBJC2__
lockdebug_lock_precedes_lock(&classInitLock, &runtimeLock);
#endif
#if __OBJC2__
// Runtime operations may occur inside SideTable locks
// (such as storeWeak calling getMethodImplementation)
SideTableLocksPrecedeLock(&runtimeLock);
SideTableLocksPrecedeLock(&classInitLock);
// Some operations may occur inside runtimeLock.
lockdebug_lock_precedes_lock(&runtimeLock, &selLock);
#if CONFIG_USE_CACHE_LOCK
lockdebug_lock_precedes_lock(&runtimeLock, &cacheUpdateLock);
#endif
lockdebug_lock_precedes_lock(&runtimeLock, &DemangleCacheLock);
#else
// Runtime operations may occur inside SideTable locks
// (such as storeWeak calling getMethodImplementation)
SideTableLocksPrecedeLock(&methodListLock);
SideTableLocksPrecedeLock(&classInitLock);
// Method lookup and fixup.
lockdebug_lock_precedes_lock(&methodListLock, &classLock);
lockdebug_lock_precedes_lock(&methodListLock, &selLock);
#if CONFIG_USE_CACHE_LOCK
lockdebug_lock_precedes_lock(&methodListLock, &cacheUpdateLock);
#endif
lockdebug_lock_precedes_lock(&methodListLock, &impLock);
lockdebug_lock_precedes_lock(&classLock, &selLock);
lockdebug_lock_precedes_lock(&classLock, &cacheUpdateLock);
#endif
// Striped locks use address order internally.
SideTableDefineLockOrder();
PropertyLocks.defineLockOrder();
StructLocks.defineLockOrder();
CppObjectLocks.defineLockOrder();
}
// LOCKDEBUG
#endif
static bool ForkIsMultithreaded;
void _objc_atfork_prepare()
{
// Save threaded-ness for the child's use.
ForkIsMultithreaded = pthread_is_threaded_np();
lockdebug_assert_no_locks_locked();
lockdebug_setInForkPrepare(true);
loadMethodLock.lock();
PropertyLocks.lockAll();
CppObjectLocks.lockAll();
AssociationsManagerLock.lock();
SideTableLockAll();
classInitLock.enter();
#if __OBJC2__
runtimeLock.lock();
DemangleCacheLock.lock();
#else
methodListLock.lock();
classLock.lock();
NXUniqueStringLock.lock();
impLock.lock();
#endif
selLock.lock();
#if CONFIG_USE_CACHE_LOCK
cacheUpdateLock.lock();
#endif
objcMsgLogLock.lock();
AltHandlerDebugLock.lock();
StructLocks.lockAll();
crashlog_lock.lock();
lockdebug_assert_all_locks_locked();
lockdebug_setInForkPrepare(false);
}
void _objc_atfork_parent()
{
lockdebug_assert_all_locks_locked();
CppObjectLocks.unlockAll();
StructLocks.unlockAll();
PropertyLocks.unlockAll();
AssociationsManagerLock.unlock();
AltHandlerDebugLock.unlock();
objcMsgLogLock.unlock();
crashlog_lock.unlock();
loadMethodLock.unlock();
#if CONFIG_USE_CACHE_LOCK
cacheUpdateLock.unlock();
#endif
selLock.unlock();
SideTableUnlockAll();
#if __OBJC2__
DemangleCacheLock.unlock();
runtimeLock.unlock();
#else
impLock.unlock();
NXUniqueStringLock.unlock();
methodListLock.unlock();
classLock.unlock();
#endif
classInitLock.leave();
lockdebug_assert_no_locks_locked();
}
void _objc_atfork_child()
{
// Turn on +initialize fork safety enforcement if applicable.
if (ForkIsMultithreaded && !DisableInitializeForkSafety) {
MultithreadedForkChild = true;
}
lockdebug_assert_all_locks_locked();
CppObjectLocks.forceResetAll();
StructLocks.forceResetAll();
PropertyLocks.forceResetAll();
AssociationsManagerLock.forceReset();
AltHandlerDebugLock.forceReset();
objcMsgLogLock.forceReset();
crashlog_lock.forceReset();
loadMethodLock.forceReset();
#if CONFIG_USE_CACHE_LOCK
cacheUpdateLock.forceReset();
#endif
selLock.forceReset();
SideTableForceResetAll();
#if __OBJC2__
DemangleCacheLock.forceReset();
runtimeLock.forceReset();
#else
impLock.forceReset();
NXUniqueStringLock.forceReset();
methodListLock.forceReset();
classLock.forceReset();
#endif
classInitLock.forceReset();
lockdebug_assert_no_locks_locked();
}
/***********************************************************************
* _objc_init
* Bootstrap initialization. Registers our image notifier with dyld.
* Called by libSystem BEFORE library initialization time
**********************************************************************/
void _objc_init(void)
{
static bool initialized = false;
if (initialized) return;
initialized = true;
// fixme defer initialization until an objc-using image is found?
environ_init();
tls_init();
static_init();
runtime_init();
exception_init();
cache_init();
_imp_implementationWithBlock_init();
_dyld_objc_notify_register(&map_images, load_images, unmap_image);
#if __OBJC2__
didCallDyldNotifyRegister = true;
#endif
}
/***********************************************************************
* _headerForAddress.
* addr can be a class or a category
**********************************************************************/
static const header_info *_headerForAddress(void *addr)
{
#if __OBJC2__
const char *segnames[] = { "__DATA", "__DATA_CONST", "__DATA_DIRTY" };
#else
const char *segnames[] = { "__OBJC" };
#endif
header_info *hi;
for (hi = FirstHeader; hi != NULL; hi = hi->getNext()) {
for (size_t i = 0; i < sizeof(segnames)/sizeof(segnames[0]); i++) {
unsigned long seg_size;
uint8_t *seg = getsegmentdata(hi->mhdr(), segnames[i], &seg_size);
if (!seg) continue;
// Is the class in this header?
if ((uint8_t *)addr >= seg && (uint8_t *)addr < seg + seg_size) {
return hi;
}
}
}
// Not found
return 0;
}
/***********************************************************************
* _headerForClass
* Return the image header containing this class, or NULL.
* Returns NULL on runtime-constructed classes, and the NSCF classes.
**********************************************************************/
const header_info *_headerForClass(Class cls)
{
return _headerForAddress(cls);
}
/**********************************************************************
* secure_open
* Securely open a file from a world-writable directory (like /tmp)
* If the file does not exist, it will be atomically created with mode 0600
* If the file exists, it must be, and remain after opening:
* 1. a regular file (in particular, not a symlink)
* 2. owned by euid
* 3. permissions 0600
* 4. link count == 1
* Returns a file descriptor or -1. Errno may or may not be set on error.
**********************************************************************/
int secure_open(const char *filename, int flags, uid_t euid)
{
struct stat fs, ls;
int fd = -1;
bool truncate = NO;
bool create = NO;
if (flags & O_TRUNC) {
// Don't truncate the file until after it is open and verified.
truncate = YES;
flags &= ~O_TRUNC;
}
if (flags & O_CREAT) {
// Don't create except when we're ready for it
create = YES;
flags &= ~O_CREAT;
flags &= ~O_EXCL;
}
if (lstat(filename, &ls) < 0) {
if (errno == ENOENT && create) {
// No such file - create it
fd = open(filename, flags | O_CREAT | O_EXCL, 0600);
if (fd >= 0) {
// File was created successfully.
// New file does not need to be truncated.
return fd;
} else {
// File creation failed.
return -1;
}
} else {
// lstat failed, or user doesn't want to create the file
return -1;
}
} else {
// lstat succeeded - verify attributes and open
if (S_ISREG(ls.st_mode) && // regular file?
ls.st_nlink == 1 && // link count == 1?
ls.st_uid == euid && // owned by euid?
(ls.st_mode & ALLPERMS) == (S_IRUSR | S_IWUSR)) // mode 0600?
{
// Attributes look ok - open it and check attributes again
fd = open(filename, flags, 0000);
if (fd >= 0) {
// File is open - double-check attributes
if (0 == fstat(fd, &fs) &&
fs.st_nlink == ls.st_nlink && // link count == 1?
fs.st_uid == ls.st_uid && // owned by euid?
fs.st_mode == ls.st_mode && // regular file, 0600?
fs.st_ino == ls.st_ino && // same inode as before?
fs.st_dev == ls.st_dev) // same device as before?
{
// File is open and OK
if (truncate) ftruncate(fd, 0);
return fd;
} else {
// Opened file looks funny - close it
close(fd);
return -1;
}
} else {
// File didn't open
return -1;
}
} else {
// Unopened file looks funny - don't open it
return -1;
}
}
}
#if TARGET_OS_IPHONE
const char *__crashreporter_info__ = NULL;
const char *CRSetCrashLogMessage(const char *msg)
{
__crashreporter_info__ = msg;
return msg;
}
const char *CRGetCrashLogMessage(void)
{
return __crashreporter_info__;
}
#endif
// TARGET_OS_MAC
#else
#error unknown OS
#endif
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