63 lines
2.2 KiB
C++
63 lines
2.2 KiB
C++
//===-- sanitizer_tls_get_addr.h --------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Handle the __tls_get_addr call.
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//
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// All this magic is specific to glibc and is required to workaround
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// the lack of interface that would tell us about the Dynamic TLS (DTLS).
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// https://sourceware.org/bugzilla/show_bug.cgi?id=16291
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//
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// The matters get worse because the glibc implementation changed between
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// 2.18 and 2.19:
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// https://groups.google.com/forum/#!topic/address-sanitizer/BfwYD8HMxTM
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//
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// Before 2.19, every DTLS chunk is allocated with __libc_memalign,
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// which we intercept and thus know where is the DTLS.
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// Since 2.19, DTLS chunks are allocated with __signal_safe_memalign,
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// which is an internal function that wraps a mmap call, neither of which
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// we can intercept. Luckily, __signal_safe_memalign has a simple parseable
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// header which we can use.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SANITIZER_TLS_GET_ADDR_H
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#define SANITIZER_TLS_GET_ADDR_H
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#include "sanitizer_common.h"
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namespace __sanitizer {
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struct DTLS {
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// Array of DTLS chunks for the current Thread.
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// If beg == 0, the chunk is unused.
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struct DTV {
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uptr beg, size;
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};
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uptr dtv_size;
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DTV *dtv; // dtv_size elements, allocated by MmapOrDie.
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// Auxiliary fields, don't access them outside sanitizer_tls_get_addr.cpp
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uptr last_memalign_size;
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uptr last_memalign_ptr;
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};
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// Returns pointer and size of a linker-allocated TLS block.
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// Each block is returned exactly once.
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DTLS::DTV *DTLS_on_tls_get_addr(void *arg, void *res, uptr static_tls_begin,
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uptr static_tls_end);
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void DTLS_on_libc_memalign(void *ptr, uptr size);
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DTLS *DTLS_Get();
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void DTLS_Destroy(); // Make sure to call this before the thread is destroyed.
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// Returns true if DTLS of suspended thread is in destruction process.
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bool DTLSInDestruction(DTLS *dtls);
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} // namespace __sanitizer
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#endif // SANITIZER_TLS_GET_ADDR_H
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