llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_tls_get_addr.h

59 lines
1.9 KiB
C++

//===-- sanitizer_tls_get_addr.h --------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Handle the __tls_get_addr call.
//
// All this magic is specific to glibc and is required to workaround
// the lack of interface that would tell us about the Dynamic TLS (DTLS).
// https://sourceware.org/bugzilla/show_bug.cgi?id=16291
//
// The matters get worse because the glibc implementation changed between
// 2.18 and 2.19:
// https://groups.google.com/forum/#!topic/address-sanitizer/BfwYD8HMxTM
//
// Before 2.19, every DTLS chunk is allocated with __libc_memalign,
// which we intercept and thus know where is the DTLS.
// Since 2.19, DTLS chunks are allocated with __signal_safe_memalign,
// which is an internal function that wraps a mmap call, neither of which
// we can intercept. Luckily, __signal_safe_memalign has a simple parseable
// header which we can use.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_TLS_GET_ADDR_H
#define SANITIZER_TLS_GET_ADDR_H
#include "sanitizer_common.h"
namespace __sanitizer {
struct DTLS {
// Array of DTLS chunks for the current Thread.
// If beg == 0, the chunk is unused.
struct DTV {
uptr beg, size;
};
uptr dtv_size;
DTV *dtv; // dtv_size elements, allocated by MmapOrDie.
// Auxiliary fields, don't access them outside sanitizer_tls_get_addr.cc
uptr last_memalign_size;
uptr last_memalign_ptr;
};
void DTLS_on_tls_get_addr(void *arg, void *res);
void DTLS_on_libc_memalign(void *ptr, uptr size);
DTLS *DTLS_Get();
void DTLS_Destroy(); // Make sure to call this before the thread is destroyed.
} // namespace __sanitizer
#endif // SANITIZER_TLS_GET_ADDR_H