//===-- tsan_interceptors_mac.cpp -----------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer (TSan), a race detector.
//
// Mac-specific interceptors.
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#if SANITIZER_APPLE
#include "interception/interception.h"
#include "tsan_interceptors.h"
#include "tsan_interface.h"
#include "tsan_interface_ann.h"
#include "tsan_spinlock_defs_mac.h"
#include "sanitizer_common/sanitizer_addrhashmap.h"
#include <errno.h>
#include <libkern/OSAtomic.h>
#include <objc/objc-sync.h>
#include <os/lock.h>
#include <sys/ucontext.h>
#if defined(__has_include) && __has_include(<xpc/xpc.h>)
#include <xpc/xpc.h>
#endif // #if defined(__has_include) && __has_include(<xpc/xpc.h>)
typedef long long_t;
extern "C" {
int getcontext(ucontext_t *ucp) __attribute__((returns_twice));
int setcontext(const ucontext_t *ucp);
}
namespace __tsan {
// The non-barrier versions of OSAtomic* functions are semantically mo_relaxed,
// but the two variants (e.g. OSAtomicAdd32 and OSAtomicAdd32Barrier) are
// actually aliases of each other, and we cannot have different interceptors for
// them, because they're actually the same function. Thus, we have to stay
// conservative and treat the non-barrier versions as mo_acq_rel.
static constexpr morder kMacOrderBarrier = mo_acq_rel;
static constexpr morder kMacOrderNonBarrier = mo_acq_rel;
static constexpr morder kMacFailureOrder = mo_relaxed;
#define OSATOMIC_INTERCEPTOR(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
TSAN_INTERCEPTOR(return_t, f, t x, volatile t *ptr) { \
SCOPED_TSAN_INTERCEPTOR(f, x, ptr); \
return tsan_atomic_f((volatile tsan_t *)ptr, x, mo); \
}
#define OSATOMIC_INTERCEPTOR_PLUS_X(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
TSAN_INTERCEPTOR(return_t, f, t x, volatile t *ptr) { \
SCOPED_TSAN_INTERCEPTOR(f, x, ptr); \
return tsan_atomic_f((volatile tsan_t *)ptr, x, mo) + x; \
}
#define OSATOMIC_INTERCEPTOR_PLUS_1(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
TSAN_INTERCEPTOR(return_t, f, volatile t *ptr) { \
SCOPED_TSAN_INTERCEPTOR(f, ptr); \
return tsan_atomic_f((volatile tsan_t *)ptr, 1, mo) + 1; \
}
#define OSATOMIC_INTERCEPTOR_MINUS_1(return_t, t, tsan_t, f, tsan_atomic_f, \
mo) \
TSAN_INTERCEPTOR(return_t, f, volatile t *ptr) { \
SCOPED_TSAN_INTERCEPTOR(f, ptr); \
return tsan_atomic_f((volatile tsan_t *)ptr, 1, mo) - 1; \
}
#define OSATOMIC_INTERCEPTORS_ARITHMETIC(f, tsan_atomic_f, m) \
m(int32_t, int32_t, a32, f##32, __tsan_atomic32_##tsan_atomic_f, \
kMacOrderNonBarrier) \
m(int32_t, int32_t, a32, f##32##Barrier, __tsan_atomic32_##tsan_atomic_f, \
kMacOrderBarrier) \
m(int64_t, int64_t, a64, f##64, __tsan_atomic64_##tsan_atomic_f, \
kMacOrderNonBarrier) \
m(int64_t, int64_t, a64, f##64##Barrier, __tsan_atomic64_##tsan_atomic_f, \
kMacOrderBarrier)
#define OSATOMIC_INTERCEPTORS_BITWISE(f, tsan_atomic_f, m, m_orig) \
m(int32_t, uint32_t, a32, f##32, __tsan_atomic32_##tsan_atomic_f, \
kMacOrderNonBarrier) \
m(int32_t, uint32_t, a32, f##32##Barrier, __tsan_atomic32_##tsan_atomic_f, \
kMacOrderBarrier) \
m_orig(int32_t, uint32_t, a32, f##32##Orig, __tsan_atomic32_##tsan_atomic_f, \
kMacOrderNonBarrier) \
m_orig(int32_t, uint32_t, a32, f##32##OrigBarrier, \
__tsan_atomic32_##tsan_atomic_f, kMacOrderBarrier)
#pragma clang diagnostic push
// OSAtomic* functions are deprecated.
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicAdd, fetch_add,
OSATOMIC_INTERCEPTOR_PLUS_X)
OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicIncrement, fetch_add,
OSATOMIC_INTERCEPTOR_PLUS_1)
OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicDecrement, fetch_sub,
OSATOMIC_INTERCEPTOR_MINUS_1)
OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicOr, fetch_or, OSATOMIC_INTERCEPTOR_PLUS_X,
OSATOMIC_INTERCEPTOR)
OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicAnd, fetch_and,
OSATOMIC_INTERCEPTOR_PLUS_X, OSATOMIC_INTERCEPTOR)
OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicXor, fetch_xor,
OSATOMIC_INTERCEPTOR_PLUS_X, OSATOMIC_INTERCEPTOR)
#define OSATOMIC_INTERCEPTORS_CAS(f, tsan_atomic_f, tsan_t, t) \
TSAN_INTERCEPTOR(bool, f, t old_value, t new_value, t volatile *ptr) { \
SCOPED_TSAN_INTERCEPTOR(f, old_value, new_value, ptr); \
return tsan_atomic_f##_compare_exchange_strong( \
(volatile tsan_t *)ptr, (tsan_t *)&old_value, (tsan_t)new_value, \
kMacOrderNonBarrier, kMacFailureOrder); \
} \
\
TSAN_INTERCEPTOR(bool, f##Barrier, t old_value, t new_value, \
t volatile *ptr) { \
SCOPED_TSAN_INTERCEPTOR(f##Barrier, old_value, new_value, ptr); \
return tsan_atomic_f##_compare_exchange_strong( \
(volatile tsan_t *)ptr, (tsan_t *)&old_value, (tsan_t)new_value, \
kMacOrderBarrier, kMacFailureOrder); \
}
#pragma clang diagnostic push
// OSAtomicCompareAndSwap* functions are deprecated.
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapInt, __tsan_atomic32, a32, int)
OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapLong, __tsan_atomic64, a64,
long_t)
OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapPtr, __tsan_atomic64, a64,
void *)
OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwap32, __tsan_atomic32, a32,
int32_t)
OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwap64, __tsan_atomic64, a64,
int64_t)
#pragma clang diagnostic pop
#define OSATOMIC_INTERCEPTOR_BITOP(f, op, clear, mo) \
TSAN_INTERCEPTOR(bool, f, uint32_t n, volatile void *ptr) { \
SCOPED_TSAN_INTERCEPTOR(f, n, ptr); \
volatile char *byte_ptr = ((volatile char *)ptr) + (n >> 3); \
char bit = 0x80u >> (n & 7); \
char mask = clear ? ~bit : bit; \
char orig_byte = op((volatile a8 *)byte_ptr, mask, mo); \
return orig_byte & bit; \
}
#define OSATOMIC_INTERCEPTORS_BITOP(f, op, clear) \
OSATOMIC_INTERCEPTOR_BITOP(f, op, clear, kMacOrderNonBarrier) \
OSATOMIC_INTERCEPTOR_BITOP(f##Barrier, op, clear, kMacOrderBarrier)
OSATOMIC_INTERCEPTORS_BITOP(OSAtomicTestAndSet, __tsan_atomic8_fetch_or, false)
OSATOMIC_INTERCEPTORS_BITOP(OSAtomicTestAndClear, __tsan_atomic8_fetch_and,
true)
TSAN_INTERCEPTOR(void, OSAtomicEnqueue, OSQueueHead *list, void *item,
size_t offset) {
SCOPED_TSAN_INTERCEPTOR(OSAtomicEnqueue, list, item, offset);
__tsan_release(item);
REAL(OSAtomicEnqueue)(list, item, offset);
}
TSAN_INTERCEPTOR(void *, OSAtomicDequeue, OSQueueHead *list, size_t offset) {
SCOPED_TSAN_INTERCEPTOR(OSAtomicDequeue, list, offset);
void *item = REAL(OSAtomicDequeue)(list, offset);
if (item) __tsan_acquire(item);
return item;
}
// OSAtomicFifoEnqueue and OSAtomicFifoDequeue are only on OS X.
#if !SANITIZER_IOS
TSAN_INTERCEPTOR(void, OSAtomicFifoEnqueue, OSFifoQueueHead *list, void *item,
size_t offset) {
SCOPED_TSAN_INTERCEPTOR(OSAtomicFifoEnqueue, list, item, offset);
__tsan_release(item);
REAL(OSAtomicFifoEnqueue)(list, item, offset);
}
TSAN_INTERCEPTOR(void *, OSAtomicFifoDequeue, OSFifoQueueHead *list,
size_t offset) {
SCOPED_TSAN_INTERCEPTOR(OSAtomicFifoDequeue, list, offset);
void *item = REAL(OSAtomicFifoDequeue)(list, offset);
if (item) __tsan_acquire(item);
return item;
}
#endif
TSAN_INTERCEPTOR(void, OSSpinLockLock, volatile OSSpinLock *lock) {
CHECK(!cur_thread()->is_dead);
if (!cur_thread()->is_inited) {
return REAL(OSSpinLockLock)(lock);
}
SCOPED_TSAN_INTERCEPTOR(OSSpinLockLock, lock);
REAL(OSSpinLockLock)(lock);
Acquire(thr, pc, (uptr)lock);
}
TSAN_INTERCEPTOR(bool, OSSpinLockTry, volatile OSSpinLock *lock) {
CHECK(!cur_thread()->is_dead);
if (!cur_thread()->is_inited) {
return REAL(OSSpinLockTry)(lock);
}
SCOPED_TSAN_INTERCEPTOR(OSSpinLockTry, lock);
bool result = REAL(OSSpinLockTry)(lock);
if (result)
Acquire(thr, pc, (uptr)lock);
return result;
}
TSAN_INTERCEPTOR(void, OSSpinLockUnlock, volatile OSSpinLock *lock) {
CHECK(!cur_thread()->is_dead);
if (!cur_thread()->is_inited) {
return REAL(OSSpinLockUnlock)(lock);
}
SCOPED_TSAN_INTERCEPTOR(OSSpinLockUnlock, lock);
Release(thr, pc, (uptr)lock);
REAL(OSSpinLockUnlock)(lock);
}
TSAN_INTERCEPTOR(void, os_lock_lock, void *lock) {
CHECK(!cur_thread()->is_dead);
if (!cur_thread()->is_inited) {
return REAL(os_lock_lock)(lock);
}
SCOPED_TSAN_INTERCEPTOR(os_lock_lock, lock);
REAL(os_lock_lock)(lock);
Acquire(thr, pc, (uptr)lock);
}
TSAN_INTERCEPTOR(bool, os_lock_trylock, void *lock) {
CHECK(!cur_thread()->is_dead);
if (!cur_thread()->is_inited) {
return REAL(os_lock_trylock)(lock);
}
SCOPED_TSAN_INTERCEPTOR(os_lock_trylock, lock);
bool result = REAL(os_lock_trylock)(lock);
if (result)
Acquire(thr, pc, (uptr)lock);
return result;
}
TSAN_INTERCEPTOR(void, os_lock_unlock, void *lock) {
CHECK(!cur_thread()->is_dead);
if (!cur_thread()->is_inited) {
return REAL(os_lock_unlock)(lock);
}
SCOPED_TSAN_INTERCEPTOR(os_lock_unlock, lock);
Release(thr, pc, (uptr)lock);
REAL(os_lock_unlock)(lock);
}
TSAN_INTERCEPTOR(void, os_unfair_lock_lock, os_unfair_lock_t lock) {
if (!cur_thread()->is_inited || cur_thread()->is_dead) {
return REAL(os_unfair_lock_lock)(lock);
}
SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock, lock);
REAL(os_unfair_lock_lock)(lock);
Acquire(thr, pc, (uptr)lock);
}
TSAN_INTERCEPTOR(void, os_unfair_lock_lock_with_options, os_unfair_lock_t lock,
u32 options) {
if (!cur_thread()->is_inited || cur_thread()->is_dead) {
return REAL(os_unfair_lock_lock_with_options)(lock, options);
}
SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock_with_options, lock, options);
REAL(os_unfair_lock_lock_with_options)(lock, options);
Acquire(thr, pc, (uptr)lock);
}
TSAN_INTERCEPTOR(bool, os_unfair_lock_trylock, os_unfair_lock_t lock) {
if (!cur_thread()->is_inited || cur_thread()->is_dead) {
return REAL(os_unfair_lock_trylock)(lock);
}
SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_trylock, lock);
bool result = REAL(os_unfair_lock_trylock)(lock);
if (result)
Acquire(thr, pc, (uptr)lock);
return result;
}
TSAN_INTERCEPTOR(void, os_unfair_lock_unlock, os_unfair_lock_t lock) {
if (!cur_thread()->is_inited || cur_thread()->is_dead) {
return REAL(os_unfair_lock_unlock)(lock);
}
SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_unlock, lock);
Release(thr, pc, (uptr)lock);
REAL(os_unfair_lock_unlock)(lock);
}
#if defined(__has_include) && __has_include(<xpc/xpc.h>)
TSAN_INTERCEPTOR(void, xpc_connection_set_event_handler,
xpc_connection_t connection, xpc_handler_t handler) {
SCOPED_TSAN_INTERCEPTOR(xpc_connection_set_event_handler, connection,
handler);
Release(thr, pc, (uptr)connection);
xpc_handler_t new_handler = ^(xpc_object_t object) {
{
SCOPED_INTERCEPTOR_RAW(xpc_connection_set_event_handler);
Acquire(thr, pc, (uptr)connection);
}
handler(object);
};
REAL(xpc_connection_set_event_handler)(connection, new_handler);
}
TSAN_INTERCEPTOR(void, xpc_connection_send_barrier, xpc_connection_t connection,
dispatch_block_t barrier) {
SCOPED_TSAN_INTERCEPTOR(xpc_connection_send_barrier, connection, barrier);
Release(thr, pc, (uptr)connection);
dispatch_block_t new_barrier = ^() {
{
SCOPED_INTERCEPTOR_RAW(xpc_connection_send_barrier);
Acquire(thr, pc, (uptr)connection);
}
barrier();
};
REAL(xpc_connection_send_barrier)(connection, new_barrier);
}
TSAN_INTERCEPTOR(void, xpc_connection_send_message_with_reply,
xpc_connection_t connection, xpc_object_t message,
dispatch_queue_t replyq, xpc_handler_t handler) {
SCOPED_TSAN_INTERCEPTOR(xpc_connection_send_message_with_reply, connection,
message, replyq, handler);
Release(thr, pc, (uptr)connection);
xpc_handler_t new_handler = ^(xpc_object_t object) {
{
SCOPED_INTERCEPTOR_RAW(xpc_connection_send_message_with_reply);
Acquire(thr, pc, (uptr)connection);
}
handler(object);
};
REAL(xpc_connection_send_message_with_reply)
(connection, message, replyq, new_handler);
}
TSAN_INTERCEPTOR(void, xpc_connection_cancel, xpc_connection_t connection) {
SCOPED_TSAN_INTERCEPTOR(xpc_connection_cancel, connection);
Release(thr, pc, (uptr)connection);
REAL(xpc_connection_cancel)(connection);
}
#endif // #if defined(__has_include) && __has_include(<xpc/xpc.h>)
// Determines whether the Obj-C object pointer is a tagged pointer. Tagged
// pointers encode the object data directly in their pointer bits and do not
// have an associated memory allocation. The Obj-C runtime uses tagged pointers
// to transparently optimize small objects.
static bool IsTaggedObjCPointer(id obj) {
const uptr kPossibleTaggedBits = 0x8000000000000001ull;
return ((uptr)obj & kPossibleTaggedBits) != 0;
}
// Returns an address which can be used to inform TSan about synchronization
// points (MutexLock/Unlock). The TSan infrastructure expects this to be a valid
// address in the process space. We do a small allocation here to obtain a
// stable address (the array backing the hash map can change). The memory is
// never free'd (leaked) and allocation and locking are slow, but this code only
// runs for @synchronized with tagged pointers, which is very rare.
static uptr GetOrCreateSyncAddress(uptr addr, ThreadState *thr, uptr pc) {
typedef AddrHashMap<uptr, 5> Map;
static Map Addresses;
Map::Handle h(&Addresses, addr);
if (h.created()) {
ThreadIgnoreBegin(thr, pc);
*h = (uptr) user_alloc(thr, pc, /*size=*/1);
ThreadIgnoreEnd(thr);
}
return *h;
}
// Returns an address on which we can synchronize given an Obj-C object pointer.
// For normal object pointers, this is just the address of the object in memory.
// Tagged pointers are not backed by an actual memory allocation, so we need to
// synthesize a valid address.
static uptr SyncAddressForObjCObject(id obj, ThreadState *thr, uptr pc) {
if (IsTaggedObjCPointer(obj))
return GetOrCreateSyncAddress((uptr)obj, thr, pc);
return (uptr)obj;
}
TSAN_INTERCEPTOR(int, objc_sync_enter, id obj) {
SCOPED_TSAN_INTERCEPTOR(objc_sync_enter, obj);
if (!obj) return REAL(objc_sync_enter)(obj);
uptr addr = SyncAddressForObjCObject(obj, thr, pc);
MutexPreLock(thr, pc, addr, MutexFlagWriteReentrant);
int result = REAL(objc_sync_enter)(obj);
CHECK_EQ(result, OBJC_SYNC_SUCCESS);
MutexPostLock(thr, pc, addr, MutexFlagWriteReentrant);
return result;
}
TSAN_INTERCEPTOR(int, objc_sync_exit, id obj) {
SCOPED_TSAN_INTERCEPTOR(objc_sync_exit, obj);
if (!obj) return REAL(objc_sync_exit)(obj);
uptr addr = SyncAddressForObjCObject(obj, thr, pc);
MutexUnlock(thr, pc, addr);
int result = REAL(objc_sync_exit)(obj);
if (result != OBJC_SYNC_SUCCESS) MutexInvalidAccess(thr, pc, addr);
return result;
}
TSAN_INTERCEPTOR(int, swapcontext, ucontext_t *oucp, const ucontext_t *ucp) {
{
SCOPED_INTERCEPTOR_RAW(swapcontext, oucp, ucp);
}
// Because of swapcontext() semantics we have no option but to copy its
// implementation here
if (!oucp || !ucp) {
errno = EINVAL;
return -1;
}
ThreadState *thr = cur_thread();
const int UCF_SWAPPED = 0x80000000;
oucp->uc_onstack &= ~UCF_SWAPPED;
thr->ignore_interceptors++;
int ret = getcontext(oucp);
if (!(oucp->uc_onstack & UCF_SWAPPED)) {
thr->ignore_interceptors--;
if (!ret) {
oucp->uc_onstack |= UCF_SWAPPED;
ret = setcontext(ucp);
}
}
return ret;
}
// On macOS, libc++ is always linked dynamically, so intercepting works the
// usual way.
#define STDCXX_INTERCEPTOR TSAN_INTERCEPTOR
namespace {
struct fake_shared_weak_count {
volatile a64 shared_owners;
volatile a64 shared_weak_owners;
virtual void _unused_0x0() = 0;
virtual void _unused_0x8() = 0;
virtual void on_zero_shared() = 0;
virtual void _unused_0x18() = 0;
virtual void on_zero_shared_weak() = 0;
virtual ~fake_shared_weak_count() = 0; // suppress -Wnon-virtual-dtor
};
} // namespace
// The following code adds libc++ interceptors for:
// void __shared_weak_count::__release_shared() _NOEXCEPT;
// bool __shared_count::__release_shared() _NOEXCEPT;
// Shared and weak pointers in C++ maintain reference counts via atomics in
// libc++.dylib, which are TSan-invisible, and this leads to false positives in
// destructor code. These interceptors re-implements the whole functions so that
// the mo_acq_rel semantics of the atomic decrement are visible.
//
// Unfortunately, the interceptors cannot simply Acquire/Release some sync
// object and call the original function, because it would have a race between
// the sync and the destruction of the object. Calling both under a lock will
// not work because the destructor can invoke this interceptor again (and even
// in a different thread, so recursive locks don't help).
STDCXX_INTERCEPTOR(void, _ZNSt3__119__shared_weak_count16__release_sharedEv,
fake_shared_weak_count *o) {
if (!flags()->shared_ptr_interceptor)
return REAL(_ZNSt3__119__shared_weak_count16__release_sharedEv)(o);
SCOPED_TSAN_INTERCEPTOR(_ZNSt3__119__shared_weak_count16__release_sharedEv,
o);
if (__tsan_atomic64_fetch_add(&o->shared_owners, -1, mo_release) == 0) {
Acquire(thr, pc, (uptr)&o->shared_owners);
o->on_zero_shared();
if (__tsan_atomic64_fetch_add(&o->shared_weak_owners, -1, mo_release) ==
0) {
Acquire(thr, pc, (uptr)&o->shared_weak_owners);
o->on_zero_shared_weak();
}
}
}
STDCXX_INTERCEPTOR(bool, _ZNSt3__114__shared_count16__release_sharedEv,
fake_shared_weak_count *o) {
if (!flags()->shared_ptr_interceptor)
return REAL(_ZNSt3__114__shared_count16__release_sharedEv)(o);
SCOPED_TSAN_INTERCEPTOR(_ZNSt3__114__shared_count16__release_sharedEv, o);
if (__tsan_atomic64_fetch_add(&o->shared_owners, -1, mo_release) == 0) {
Acquire(thr, pc, (uptr)&o->shared_owners);
o->on_zero_shared();
return true;
}
return false;
}
namespace {
struct call_once_callback_args {
void (*orig_func)(void *arg);
void *orig_arg;
void *flag;
};
void call_once_callback_wrapper(void *arg) {
call_once_callback_args *new_args = (call_once_callback_args *)arg;
new_args->orig_func(new_args->orig_arg);
__tsan_release(new_args->flag);
}
} // namespace
// This adds a libc++ interceptor for:
// void __call_once(volatile unsigned long&, void*, void(*)(void*));
// C++11 call_once is implemented via an internal function __call_once which is
// inside libc++.dylib, and the atomic release store inside it is thus
// TSan-invisible. To avoid false positives, this interceptor wraps the callback
// function and performs an explicit Release after the user code has run.
STDCXX_INTERCEPTOR(void, _ZNSt3__111__call_onceERVmPvPFvS2_E, void *flag,
void *arg, void (*func)(void *arg)) {
call_once_callback_args new_args = {func, arg, flag};
REAL(_ZNSt3__111__call_onceERVmPvPFvS2_E)(flag, &new_args,
call_once_callback_wrapper);
}
} // namespace __tsan
#endif // SANITIZER_APPLE
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