Abseil Common Libraries (C++) (grcp 依赖)
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134 lines
4.6 KiB
134 lines
4.6 KiB
/* |
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* Copyright 2017 The Abseil Authors. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* https://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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// Allow dynamic symbol lookup for in-memory Elf images. |
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#ifndef ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_ |
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#define ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_ |
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// Including this will define the __GLIBC__ macro if glibc is being |
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// used. |
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#include <climits> |
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#include "absl/base/config.h" |
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// Maybe one day we can rewrite this file not to require the elf |
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// symbol extensions in glibc, but for right now we need them. |
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#ifdef ABSL_HAVE_ELF_MEM_IMAGE |
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#error ABSL_HAVE_ELF_MEM_IMAGE cannot be directly set |
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#endif |
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#if defined(__ELF__) && defined(__GLIBC__) && !defined(__native_client__) && \ |
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!defined(__asmjs__) && !defined(__wasm__) |
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#define ABSL_HAVE_ELF_MEM_IMAGE 1 |
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#endif |
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#ifdef ABSL_HAVE_ELF_MEM_IMAGE |
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#include <link.h> // for ElfW |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace debugging_internal { |
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// An in-memory ELF image (may not exist on disk). |
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class ElfMemImage { |
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private: |
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// Sentinel: there could never be an elf image at &kInvalidBaseSentinel. |
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static const int kInvalidBaseSentinel; |
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public: |
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// Sentinel: there could never be an elf image at this address. |
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static constexpr const void *const kInvalidBase = |
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static_cast<const void*>(&kInvalidBaseSentinel); |
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// Information about a single vdso symbol. |
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// All pointers are into .dynsym, .dynstr, or .text of the VDSO. |
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// Do not free() them or modify through them. |
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struct SymbolInfo { |
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const char *name; // E.g. "__vdso_getcpu" |
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const char *version; // E.g. "LINUX_2.6", could be "" |
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// for unversioned symbol. |
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const void *address; // Relocated symbol address. |
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const ElfW(Sym) *symbol; // Symbol in the dynamic symbol table. |
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}; |
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// Supports iteration over all dynamic symbols. |
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class SymbolIterator { |
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public: |
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friend class ElfMemImage; |
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const SymbolInfo *operator->() const; |
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const SymbolInfo &operator*() const; |
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SymbolIterator& operator++(); |
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bool operator!=(const SymbolIterator &rhs) const; |
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bool operator==(const SymbolIterator &rhs) const; |
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private: |
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SymbolIterator(const void *const image, int index); |
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void Update(int incr); |
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SymbolInfo info_; |
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int index_; |
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const void *const image_; |
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}; |
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explicit ElfMemImage(const void *base); |
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void Init(const void *base); |
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bool IsPresent() const { return ehdr_ != nullptr; } |
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const ElfW(Phdr)* GetPhdr(int index) const; |
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const ElfW(Sym)* GetDynsym(int index) const; |
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const ElfW(Versym)* GetVersym(int index) const; |
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const ElfW(Verdef)* GetVerdef(int index) const; |
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const ElfW(Verdaux)* GetVerdefAux(const ElfW(Verdef) *verdef) const; |
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const char* GetDynstr(ElfW(Word) offset) const; |
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const void* GetSymAddr(const ElfW(Sym) *sym) const; |
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const char* GetVerstr(ElfW(Word) offset) const; |
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int GetNumSymbols() const; |
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SymbolIterator begin() const; |
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SymbolIterator end() const; |
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// Look up versioned dynamic symbol in the image. |
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// Returns false if image is not present, or doesn't contain given |
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// symbol/version/type combination. |
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// If info_out is non-null, additional details are filled in. |
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bool LookupSymbol(const char *name, const char *version, |
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int symbol_type, SymbolInfo *info_out) const; |
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// Find info about symbol (if any) which overlaps given address. |
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// Returns true if symbol was found; false if image isn't present |
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// or doesn't have a symbol overlapping given address. |
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// If info_out is non-null, additional details are filled in. |
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bool LookupSymbolByAddress(const void *address, SymbolInfo *info_out) const; |
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private: |
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const ElfW(Ehdr) *ehdr_; |
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const ElfW(Sym) *dynsym_; |
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const ElfW(Versym) *versym_; |
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const ElfW(Verdef) *verdef_; |
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const ElfW(Word) *hash_; |
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const char *dynstr_; |
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size_t strsize_; |
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size_t verdefnum_; |
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ElfW(Addr) link_base_; // Link-time base (p_vaddr of first PT_LOAD). |
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}; |
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} // namespace debugging_internal |
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ABSL_NAMESPACE_END |
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} // namespace absl |
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#endif // ABSL_HAVE_ELF_MEM_IMAGE |
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#endif // ABSL_DEBUGGING_INTERNAL_ELF_MEM_IMAGE_H_
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