scudo_tsd_exclusive.cpp
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//===-- scudo_tsd_exclusive.cpp ---------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// Scudo exclusive TSD implementation.
///
//===----------------------------------------------------------------------===//
#include "scudo_tsd.h"
#if SCUDO_TSD_EXCLUSIVE
namespace __scudo {
static pthread_once_t GlobalInitialized = PTHREAD_ONCE_INIT;
static pthread_key_t PThreadKey;
__attribute__((tls_model("initial-exec")))
THREADLOCAL ThreadState ScudoThreadState = ThreadNotInitialized;
__attribute__((tls_model("initial-exec")))
THREADLOCAL ScudoTSD TSD;
// Fallback TSD for when the thread isn't initialized yet or is torn down. It
// can be shared between multiple threads and as such must be locked.
ScudoTSD FallbackTSD;
static void teardownThread(void *Ptr) {
uptr I = reinterpret_cast<uptr>(Ptr);
// The glibc POSIX thread-local-storage deallocation routine calls user
// provided destructors in a loop of PTHREAD_DESTRUCTOR_ITERATIONS.
// We want to be called last since other destructors might call free and the
// like, so we wait until PTHREAD_DESTRUCTOR_ITERATIONS before draining the
// quarantine and swallowing the cache.
if (I > 1) {
// If pthread_setspecific fails, we will go ahead with the teardown.
if (LIKELY(pthread_setspecific(PThreadKey,
reinterpret_cast<void *>(I - 1)) == 0))
return;
}
TSD.commitBack();
ScudoThreadState = ThreadTornDown;
}
static void initOnce() {
CHECK_EQ(pthread_key_create(&PThreadKey, teardownThread), 0);
initScudo();
FallbackTSD.init();
}
void initThread(bool MinimalInit) {
CHECK_EQ(pthread_once(&GlobalInitialized, initOnce), 0);
if (UNLIKELY(MinimalInit))
return;
CHECK_EQ(pthread_setspecific(PThreadKey, reinterpret_cast<void *>(
GetPthreadDestructorIterations())), 0);
TSD.init();
ScudoThreadState = ThreadInitialized;
}
} // namespace __scudo
#endif // SCUDO_TSD_EXCLUSIVE