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https://github.com/ClickHouse/ClickHouse.git
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135 lines
3.5 KiB
C++
135 lines
3.5 KiB
C++
#ifdef __ELF__
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#include <Common/Elf.h>
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#include <Common/Exception.h>
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#include <string.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int CANNOT_PARSE_ELF;
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}
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Elf::Elf(const std::string & path)
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: in(path, 0)
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{
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/// Check if it's an elf.
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elf_size = in.buffer().size();
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if (elf_size < sizeof(ElfEhdr))
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throw Exception("The size of supposedly ELF file is too small", ErrorCodes::CANNOT_PARSE_ELF);
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mapped = in.buffer().begin();
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header = reinterpret_cast<const ElfEhdr *>(mapped);
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if (memcmp(header->e_ident, "\x7F""ELF", 4) != 0)
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throw Exception("The file is not ELF according to magic", ErrorCodes::CANNOT_PARSE_ELF);
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/// Get section header.
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ElfOff section_header_offset = header->e_shoff;
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uint16_t section_header_num_entries = header->e_shnum;
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if (!section_header_offset
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|| !section_header_num_entries
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|| section_header_offset + section_header_num_entries * sizeof(ElfShdr) > elf_size)
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throw Exception("The ELF is truncated (section header points after end of file)", ErrorCodes::CANNOT_PARSE_ELF);
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section_headers = reinterpret_cast<const ElfShdr *>(mapped + section_header_offset);
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/// The string table with section names.
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auto section_names_strtab = findSection([&](const Section & section, size_t idx)
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{
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return section.header.sh_type == SHT_STRTAB && header->e_shstrndx == idx;
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});
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if (!section_names_strtab)
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throw Exception("The ELF doesn't have string table with section names", ErrorCodes::CANNOT_PARSE_ELF);
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ElfOff section_names_offset = section_names_strtab->header.sh_offset;
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if (section_names_offset >= elf_size)
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throw Exception("The ELF is truncated (section names string table points after end of file)", ErrorCodes::CANNOT_PARSE_ELF);
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section_names = reinterpret_cast<const char *>(mapped + section_names_offset);
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}
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Elf::Section::Section(const ElfShdr & header_, const Elf & elf_)
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: header(header_), elf(elf_)
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{
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}
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bool Elf::iterateSections(std::function<bool(const Section & section, size_t idx)> && pred) const
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{
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for (size_t idx = 0; idx < header->e_shnum; ++idx)
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{
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Section section(section_headers[idx], *this);
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/// Sections spans after end of file.
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if (section.header.sh_offset + section.header.sh_size > elf_size)
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continue;
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if (pred(section, idx))
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return true;
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}
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return false;
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}
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std::optional<Elf::Section> Elf::findSection(std::function<bool(const Section & section, size_t idx)> && pred) const
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{
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std::optional<Elf::Section> result;
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iterateSections([&](const Section & section, size_t idx)
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{
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if (pred(section, idx))
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{
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result.emplace(section);
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return true;
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}
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return false;
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});
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return result;
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}
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std::optional<Elf::Section> Elf::findSectionByName(const char * name) const
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{
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return findSection([&](const Section & section, size_t) { return 0 == strcmp(name, section.name()); });
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}
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const char * Elf::Section::name() const
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{
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if (!elf.section_names)
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throw Exception("Section names are not initialized", ErrorCodes::CANNOT_PARSE_ELF);
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/// TODO buffer overflow is possible, we may need to check strlen.
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return elf.section_names + header.sh_name;
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}
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const char * Elf::Section::begin() const
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{
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return elf.mapped + header.sh_offset;
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}
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const char * Elf::Section::end() const
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{
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return begin() + size();
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}
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size_t Elf::Section::size() const
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{
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return header.sh_size;
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}
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}
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#endif
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