| /* |
| * Copyright (C) 2019 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #pragma once |
| |
| #include <link.h> |
| #include <pthread.h> |
| #include <stdatomic.h> |
| #include <stdint.h> |
| #include <sys/cdefs.h> |
| |
| struct TlsSegment { |
| size_t size = 0; |
| size_t alignment = 1; |
| const void* init_ptr = ""; // Field is non-null even when init_size is 0. |
| size_t init_size = 0; |
| }; |
| |
| __LIBC_HIDDEN__ bool __bionic_get_tls_segment(const ElfW(Phdr)* phdr_table, size_t phdr_count, |
| ElfW(Addr) load_bias, TlsSegment* out); |
| |
| __LIBC_HIDDEN__ bool __bionic_check_tls_alignment(size_t* alignment); |
| |
| struct StaticTlsLayout { |
| constexpr StaticTlsLayout() {} |
| |
| private: |
| size_t offset_ = 0; |
| size_t alignment_ = 1; |
| bool overflowed_ = false; |
| |
| // Offsets to various Bionic TLS structs from the beginning of static TLS. |
| size_t offset_bionic_tcb_ = SIZE_MAX; |
| size_t offset_bionic_tls_ = SIZE_MAX; |
| |
| public: |
| size_t offset_bionic_tcb() const { return offset_bionic_tcb_; } |
| size_t offset_bionic_tls() const { return offset_bionic_tls_; } |
| size_t offset_thread_pointer() const; |
| |
| size_t size() const { return offset_; } |
| size_t alignment() const { return alignment_; } |
| bool overflowed() const { return overflowed_; } |
| |
| size_t reserve_exe_segment_and_tcb(const TlsSegment* exe_segment, const char* progname); |
| void reserve_bionic_tls(); |
| size_t reserve_solib_segment(const TlsSegment& segment) { |
| return reserve(segment.size, segment.alignment); |
| } |
| void finish_layout(); |
| |
| private: |
| size_t reserve(size_t size, size_t alignment); |
| |
| template <typename T> size_t reserve_type() { |
| return reserve(sizeof(T), alignof(T)); |
| } |
| |
| size_t round_up_with_overflow_check(size_t value, size_t alignment); |
| }; |
| |
| // A descriptor for a single ELF TLS module. |
| struct TlsModule { |
| TlsSegment segment; |
| |
| // Offset into the static TLS block or SIZE_MAX for a dynamic module. |
| size_t static_offset = SIZE_MAX; |
| |
| // The generation in which this module was loaded. Dynamic TLS lookups use |
| // this field to detect when a module has been unloaded. |
| size_t first_generation = 0; |
| |
| // Used by the dynamic linker to track the associated soinfo* object. |
| void* soinfo_ptr = nullptr; |
| }; |
| |
| // Table of the ELF TLS modules. Either the dynamic linker or the static |
| // initialization code prepares this table, and it's then used during thread |
| // creation and for dynamic TLS lookups. |
| struct TlsModules { |
| constexpr TlsModules() {} |
| |
| // A generation counter. The value is incremented each time an solib is loaded |
| // or unloaded. |
| _Atomic(size_t) generation = 0; |
| |
| // Access to the TlsModule[] table requires taking this lock. |
| pthread_rwlock_t rwlock = PTHREAD_RWLOCK_INITIALIZER; |
| |
| // Pointer to a block of TlsModule objects. The first module has ID 1 and |
| // is stored at index 0 in this table. |
| size_t module_count = 0; |
| TlsModule* module_table = nullptr; |
| }; |
| |
| void __init_static_tls(void* static_tls); |