| /* |
| * Copyright (C) 2012 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "elf_writer_quick.h" |
| |
| #include "base/logging.h" |
| #include "base/unix_file/fd_file.h" |
| #include "buffered_output_stream.h" |
| #include "driver/compiler_driver.h" |
| #include "dwarf.h" |
| #include "elf_utils.h" |
| #include "file_output_stream.h" |
| #include "globals.h" |
| #include "oat.h" |
| #include "oat_writer.h" |
| #include "utils.h" |
| |
| namespace art { |
| |
| static constexpr Elf32_Word NextOffset(const Elf32_Shdr& cur, const Elf32_Shdr& prev) { |
| return RoundUp(prev.sh_size + prev.sh_offset, cur.sh_addralign); |
| } |
| |
| static uint8_t MakeStInfo(uint8_t binding, uint8_t type) { |
| return ((binding) << 4) + ((type) & 0xf); |
| } |
| |
| bool ElfWriterQuick::ElfBuilder::Write() { |
| // The basic layout of the elf file. Order may be different in final output. |
| // +-------------------------+ |
| // | Elf32_Ehdr | |
| // +-------------------------+ |
| // | Elf32_Phdr PHDR | |
| // | Elf32_Phdr LOAD R | .dynsym .dynstr .hash .rodata |
| // | Elf32_Phdr LOAD R X | .text |
| // | Elf32_Phdr LOAD RW | .dynamic |
| // | Elf32_Phdr DYNAMIC | .dynamic |
| // +-------------------------+ |
| // | .dynsym | |
| // | Elf32_Sym STN_UNDEF | |
| // | Elf32_Sym oatdata | |
| // | Elf32_Sym oatexec | |
| // | Elf32_Sym oatlastword | |
| // +-------------------------+ |
| // | .dynstr | |
| // | \0 | |
| // | oatdata\0 | |
| // | oatexec\0 | |
| // | oatlastword\0 | |
| // | boot.oat\0 | |
| // +-------------------------+ |
| // | .hash | |
| // | Elf32_Word nbucket = b | |
| // | Elf32_Word nchain = c | |
| // | Elf32_Word bucket[0] | |
| // | ... | |
| // | Elf32_Word bucket[b - 1]| |
| // | Elf32_Word chain[0] | |
| // | ... | |
| // | Elf32_Word chain[c - 1] | |
| // +-------------------------+ |
| // | .rodata | |
| // | oatdata..oatexec-4 | |
| // +-------------------------+ |
| // | .text | |
| // | oatexec..oatlastword | |
| // +-------------------------+ |
| // | .dynamic | |
| // | Elf32_Dyn DT_SONAME | |
| // | Elf32_Dyn DT_HASH | |
| // | Elf32_Dyn DT_SYMTAB | |
| // | Elf32_Dyn DT_SYMENT | |
| // | Elf32_Dyn DT_STRTAB | |
| // | Elf32_Dyn DT_STRSZ | |
| // | Elf32_Dyn DT_NULL | |
| // +-------------------------+ (Optional) |
| // | .strtab | (Optional) |
| // | program symbol names | (Optional) |
| // +-------------------------+ (Optional) |
| // | .symtab | (Optional) |
| // | program symbols | (Optional) |
| // +-------------------------+ |
| // | .shstrtab | |
| // | \0 | |
| // | .dynamic\0 | |
| // | .dynsym\0 | |
| // | .dynstr\0 | |
| // | .hash\0 | |
| // | .rodata\0 | |
| // | .text\0 | |
| // | .shstrtab\0 | |
| // | .symtab\0 | (Optional) |
| // | .strtab\0 | (Optional) |
| // | .debug_str\0 | (Optional) |
| // | .debug_info\0 | (Optional) |
| // | .eh_frame\0 | (Optional) |
| // | .debug_abbrev\0 | (Optional) |
| // +-------------------------+ (Optional) |
| // | .debug_str | (Optional) |
| // +-------------------------+ (Optional) |
| // | .debug_info | (Optional) |
| // +-------------------------+ (Optional) |
| // | .eh_frame | (Optional) |
| // +-------------------------+ (Optional) |
| // | .debug_abbrev | (Optional) |
| // +-------------------------+ |
| // | Elf32_Shdr NULL | |
| // | Elf32_Shdr .dynsym | |
| // | Elf32_Shdr .dynstr | |
| // | Elf32_Shdr .hash | |
| // | Elf32_Shdr .text | |
| // | Elf32_Shdr .rodata | |
| // | Elf32_Shdr .dynamic | |
| // | Elf32_Shdr .shstrtab | |
| // | Elf32_Shdr .debug_str | (Optional) |
| // | Elf32_Shdr .debug_info | (Optional) |
| // | Elf32_Shdr .eh_frame | (Optional) |
| // | Elf32_Shdr .debug_abbrev| (Optional) |
| // +-------------------------+ |
| |
| |
| if (fatal_error_) { |
| return false; |
| } |
| // Step 1. Figure out all the offsets. |
| |
| // What phdr is. |
| uint32_t phdr_offset = sizeof(Elf32_Ehdr); |
| const uint8_t PH_PHDR = 0; |
| const uint8_t PH_LOAD_R__ = 1; |
| const uint8_t PH_LOAD_R_X = 2; |
| const uint8_t PH_LOAD_RW_ = 3; |
| const uint8_t PH_DYNAMIC = 4; |
| const uint8_t PH_NUM = 5; |
| uint32_t phdr_size = sizeof(Elf32_Phdr) * PH_NUM; |
| if (debug_logging_) { |
| LOG(INFO) << "phdr_offset=" << phdr_offset << std::hex << " " << phdr_offset; |
| LOG(INFO) << "phdr_size=" << phdr_size << std::hex << " " << phdr_size; |
| } |
| Elf32_Phdr program_headers[PH_NUM]; |
| memset(&program_headers, 0, sizeof(program_headers)); |
| program_headers[PH_PHDR].p_type = PT_PHDR; |
| program_headers[PH_PHDR].p_offset = phdr_offset; |
| program_headers[PH_PHDR].p_vaddr = phdr_offset; |
| program_headers[PH_PHDR].p_paddr = phdr_offset; |
| program_headers[PH_PHDR].p_filesz = sizeof(program_headers); |
| program_headers[PH_PHDR].p_memsz = sizeof(program_headers); |
| program_headers[PH_PHDR].p_flags = PF_R; |
| program_headers[PH_PHDR].p_align = sizeof(Elf32_Word); |
| |
| program_headers[PH_LOAD_R__].p_type = PT_LOAD; |
| program_headers[PH_LOAD_R__].p_offset = 0; |
| program_headers[PH_LOAD_R__].p_vaddr = 0; |
| program_headers[PH_LOAD_R__].p_paddr = 0; |
| program_headers[PH_LOAD_R__].p_flags = PF_R; |
| |
| program_headers[PH_LOAD_R_X].p_type = PT_LOAD; |
| program_headers[PH_LOAD_R_X].p_flags = PF_R | PF_X; |
| |
| program_headers[PH_LOAD_RW_].p_type = PT_LOAD; |
| program_headers[PH_LOAD_RW_].p_flags = PF_R | PF_W; |
| |
| program_headers[PH_DYNAMIC].p_type = PT_DYNAMIC; |
| program_headers[PH_DYNAMIC].p_flags = PF_R | PF_W; |
| |
| // Get the dynstr string. |
| std::string dynstr(dynsym_builder_.GenerateStrtab()); |
| |
| // Add the SONAME to the dynstr. |
| uint32_t dynstr_soname_offset = dynstr.size(); |
| std::string file_name(elf_file_->GetPath()); |
| size_t directory_separator_pos = file_name.rfind('/'); |
| if (directory_separator_pos != std::string::npos) { |
| file_name = file_name.substr(directory_separator_pos + 1); |
| } |
| dynstr += file_name; |
| dynstr += '\0'; |
| if (debug_logging_) { |
| LOG(INFO) << "dynstr size (bytes) =" << dynstr.size() |
| << std::hex << " " << dynstr.size(); |
| LOG(INFO) << "dynsym size (elements)=" << dynsym_builder_.GetSize() |
| << std::hex << " " << dynsym_builder_.GetSize(); |
| } |
| |
| // get the strtab |
| std::string strtab; |
| if (IncludingDebugSymbols()) { |
| strtab = symtab_builder_.GenerateStrtab(); |
| if (debug_logging_) { |
| LOG(INFO) << "strtab size (bytes) =" << strtab.size() |
| << std::hex << " " << strtab.size(); |
| LOG(INFO) << "symtab size (elements) =" << symtab_builder_.GetSize() |
| << std::hex << " " << symtab_builder_.GetSize(); |
| } |
| } |
| |
| // Get the section header string table. |
| std::vector<Elf32_Shdr*> section_ptrs; |
| std::string shstrtab; |
| shstrtab += '\0'; |
| |
| // Setup sym_undef |
| Elf32_Shdr null_hdr; |
| memset(&null_hdr, 0, sizeof(null_hdr)); |
| null_hdr.sh_type = SHT_NULL; |
| null_hdr.sh_link = SHN_UNDEF; |
| section_ptrs.push_back(&null_hdr); |
| |
| uint32_t section_index = 1; |
| |
| // setup .dynsym |
| section_ptrs.push_back(&dynsym_builder_.section_); |
| AssignSectionStr(&dynsym_builder_, &shstrtab); |
| dynsym_builder_.section_index_ = section_index++; |
| |
| // Setup .dynstr |
| section_ptrs.push_back(&dynsym_builder_.strtab_.section_); |
| AssignSectionStr(&dynsym_builder_.strtab_, &shstrtab); |
| dynsym_builder_.strtab_.section_index_ = section_index++; |
| |
| // Setup .hash |
| section_ptrs.push_back(&hash_builder_.section_); |
| AssignSectionStr(&hash_builder_, &shstrtab); |
| hash_builder_.section_index_ = section_index++; |
| |
| // Setup .rodata |
| section_ptrs.push_back(&rodata_builder_.section_); |
| AssignSectionStr(&rodata_builder_, &shstrtab); |
| rodata_builder_.section_index_ = section_index++; |
| |
| // Setup .text |
| section_ptrs.push_back(&text_builder_.section_); |
| AssignSectionStr(&text_builder_, &shstrtab); |
| text_builder_.section_index_ = section_index++; |
| |
| // Setup .dynamic |
| section_ptrs.push_back(&dynamic_builder_.section_); |
| AssignSectionStr(&dynamic_builder_, &shstrtab); |
| dynamic_builder_.section_index_ = section_index++; |
| |
| if (IncludingDebugSymbols()) { |
| // Setup .symtab |
| section_ptrs.push_back(&symtab_builder_.section_); |
| AssignSectionStr(&symtab_builder_, &shstrtab); |
| symtab_builder_.section_index_ = section_index++; |
| |
| // Setup .strtab |
| section_ptrs.push_back(&symtab_builder_.strtab_.section_); |
| AssignSectionStr(&symtab_builder_.strtab_, &shstrtab); |
| symtab_builder_.strtab_.section_index_ = section_index++; |
| } |
| ElfRawSectionBuilder* it = other_builders_.data(); |
| for (uint32_t cnt = 0; cnt < other_builders_.size(); ++it, ++cnt) { |
| // Setup all the other sections. |
| section_ptrs.push_back(&it->section_); |
| AssignSectionStr(it, &shstrtab); |
| it->section_index_ = section_index++; |
| } |
| |
| // Setup shstrtab |
| section_ptrs.push_back(&shstrtab_builder_.section_); |
| AssignSectionStr(&shstrtab_builder_, &shstrtab); |
| shstrtab_builder_.section_index_ = section_index++; |
| |
| if (debug_logging_) { |
| LOG(INFO) << ".shstrtab size (bytes) =" << shstrtab.size() |
| << std::hex << " " << shstrtab.size(); |
| LOG(INFO) << "section list size (elements)=" << section_ptrs.size() |
| << std::hex << " " << section_ptrs.size(); |
| } |
| |
| // Fill in the hash section. |
| std::vector<Elf32_Word> hash = dynsym_builder_.GenerateHashContents(); |
| |
| if (debug_logging_) { |
| LOG(INFO) << ".hash size (bytes)=" << hash.size() * sizeof(Elf32_Word) |
| << std::hex << " " << hash.size() * sizeof(Elf32_Word); |
| } |
| |
| Elf32_Word base_offset = sizeof(Elf32_Ehdr) + sizeof(program_headers); |
| std::vector<ElfFilePiece> pieces; |
| |
| // Get the layout in the sections. |
| // |
| // Get the layout of the dynsym section. |
| dynsym_builder_.section_.sh_offset = RoundUp(base_offset, dynsym_builder_.section_.sh_addralign); |
| dynsym_builder_.section_.sh_addr = dynsym_builder_.section_.sh_offset; |
| dynsym_builder_.section_.sh_size = dynsym_builder_.GetSize() * sizeof(Elf32_Sym); |
| dynsym_builder_.section_.sh_link = dynsym_builder_.GetLink(); |
| |
| // Get the layout of the dynstr section. |
| dynsym_builder_.strtab_.section_.sh_offset = NextOffset(dynsym_builder_.strtab_.section_, |
| dynsym_builder_.section_); |
| dynsym_builder_.strtab_.section_.sh_addr = dynsym_builder_.strtab_.section_.sh_offset; |
| dynsym_builder_.strtab_.section_.sh_size = dynstr.size(); |
| dynsym_builder_.strtab_.section_.sh_link = dynsym_builder_.strtab_.GetLink(); |
| |
| // Get the layout of the hash section |
| hash_builder_.section_.sh_offset = NextOffset(hash_builder_.section_, |
| dynsym_builder_.strtab_.section_); |
| hash_builder_.section_.sh_addr = hash_builder_.section_.sh_offset; |
| hash_builder_.section_.sh_size = hash.size() * sizeof(Elf32_Word); |
| hash_builder_.section_.sh_link = hash_builder_.GetLink(); |
| |
| // Get the layout of the rodata section. |
| rodata_builder_.section_.sh_offset = NextOffset(rodata_builder_.section_, |
| hash_builder_.section_); |
| rodata_builder_.section_.sh_addr = rodata_builder_.section_.sh_offset; |
| rodata_builder_.section_.sh_size = rodata_builder_.size_; |
| rodata_builder_.section_.sh_link = rodata_builder_.GetLink(); |
| |
| // Get the layout of the text section. |
| text_builder_.section_.sh_offset = NextOffset(text_builder_.section_, rodata_builder_.section_); |
| text_builder_.section_.sh_addr = text_builder_.section_.sh_offset; |
| text_builder_.section_.sh_size = text_builder_.size_; |
| text_builder_.section_.sh_link = text_builder_.GetLink(); |
| CHECK_ALIGNED(rodata_builder_.section_.sh_offset + rodata_builder_.section_.sh_size, kPageSize); |
| |
| // Get the layout of the dynamic section. |
| dynamic_builder_.section_.sh_offset = NextOffset(dynamic_builder_.section_, |
| text_builder_.section_); |
| dynamic_builder_.section_.sh_addr = dynamic_builder_.section_.sh_offset; |
| dynamic_builder_.section_.sh_size = dynamic_builder_.GetSize() * sizeof(Elf32_Dyn); |
| dynamic_builder_.section_.sh_link = dynamic_builder_.GetLink(); |
| |
| Elf32_Shdr prev = dynamic_builder_.section_; |
| if (IncludingDebugSymbols()) { |
| // Get the layout of the symtab section. |
| symtab_builder_.section_.sh_offset = NextOffset(symtab_builder_.section_, |
| dynamic_builder_.section_); |
| symtab_builder_.section_.sh_addr = 0; |
| // Add to leave space for the null symbol. |
| symtab_builder_.section_.sh_size = symtab_builder_.GetSize() * sizeof(Elf32_Sym); |
| symtab_builder_.section_.sh_link = symtab_builder_.GetLink(); |
| |
| // Get the layout of the dynstr section. |
| symtab_builder_.strtab_.section_.sh_offset = NextOffset(symtab_builder_.strtab_.section_, |
| symtab_builder_.section_); |
| symtab_builder_.strtab_.section_.sh_addr = 0; |
| symtab_builder_.strtab_.section_.sh_size = strtab.size(); |
| symtab_builder_.strtab_.section_.sh_link = symtab_builder_.strtab_.GetLink(); |
| |
| prev = symtab_builder_.strtab_.section_; |
| } |
| if (debug_logging_) { |
| LOG(INFO) << "dynsym off=" << dynsym_builder_.section_.sh_offset |
| << " dynsym size=" << dynsym_builder_.section_.sh_size; |
| LOG(INFO) << "dynstr off=" << dynsym_builder_.strtab_.section_.sh_offset |
| << " dynstr size=" << dynsym_builder_.strtab_.section_.sh_size; |
| LOG(INFO) << "hash off=" << hash_builder_.section_.sh_offset |
| << " hash size=" << hash_builder_.section_.sh_size; |
| LOG(INFO) << "rodata off=" << rodata_builder_.section_.sh_offset |
| << " rodata size=" << rodata_builder_.section_.sh_size; |
| LOG(INFO) << "text off=" << text_builder_.section_.sh_offset |
| << " text size=" << text_builder_.section_.sh_size; |
| LOG(INFO) << "dynamic off=" << dynamic_builder_.section_.sh_offset |
| << " dynamic size=" << dynamic_builder_.section_.sh_size; |
| if (IncludingDebugSymbols()) { |
| LOG(INFO) << "symtab off=" << symtab_builder_.section_.sh_offset |
| << " symtab size=" << symtab_builder_.section_.sh_size; |
| LOG(INFO) << "strtab off=" << symtab_builder_.strtab_.section_.sh_offset |
| << " strtab size=" << symtab_builder_.strtab_.section_.sh_size; |
| } |
| } |
| // Get the layout of the extra sections. (This will deal with the debug |
| // sections if they are there) |
| for (auto it = other_builders_.begin(); it != other_builders_.end(); ++it) { |
| it->section_.sh_offset = NextOffset(it->section_, prev); |
| it->section_.sh_addr = 0; |
| it->section_.sh_size = it->GetBuffer()->size(); |
| it->section_.sh_link = it->GetLink(); |
| pieces.push_back(ElfFilePiece(it->name_, it->section_.sh_offset, |
| it->GetBuffer()->data(), it->GetBuffer()->size())); |
| prev = it->section_; |
| if (debug_logging_) { |
| LOG(INFO) << it->name_ << " off=" << it->section_.sh_offset |
| << " " << it->name_ << " size=" << it->section_.sh_size; |
| } |
| } |
| // Get the layout of the shstrtab section |
| shstrtab_builder_.section_.sh_offset = NextOffset(shstrtab_builder_.section_, prev); |
| shstrtab_builder_.section_.sh_addr = 0; |
| shstrtab_builder_.section_.sh_size = shstrtab.size(); |
| shstrtab_builder_.section_.sh_link = shstrtab_builder_.GetLink(); |
| if (debug_logging_) { |
| LOG(INFO) << "shstrtab off=" << shstrtab_builder_.section_.sh_offset |
| << " shstrtab size=" << shstrtab_builder_.section_.sh_size; |
| } |
| |
| // The section list comes after come after. |
| Elf32_Word sections_offset = RoundUp( |
| shstrtab_builder_.section_.sh_offset + shstrtab_builder_.section_.sh_size, |
| sizeof(Elf32_Word)); |
| |
| // Setup the actual symbol arrays. |
| std::vector<Elf32_Sym> dynsym = dynsym_builder_.GenerateSymtab(); |
| CHECK_EQ(dynsym.size() * sizeof(Elf32_Sym), dynsym_builder_.section_.sh_size); |
| std::vector<Elf32_Sym> symtab; |
| if (IncludingDebugSymbols()) { |
| symtab = symtab_builder_.GenerateSymtab(); |
| CHECK_EQ(symtab.size() * sizeof(Elf32_Sym), symtab_builder_.section_.sh_size); |
| } |
| |
| // Setup the dynamic section. |
| // This will add the 2 values we cannot know until now time, namely the size |
| // and the soname_offset. |
| std::vector<Elf32_Dyn> dynamic = dynamic_builder_.GetDynamics(dynstr.size(), |
| dynstr_soname_offset); |
| CHECK_EQ(dynamic.size() * sizeof(Elf32_Dyn), dynamic_builder_.section_.sh_size); |
| |
| // Finish setup of the program headers now that we know the layout of the |
| // whole file. |
| Elf32_Word load_r_size = rodata_builder_.section_.sh_offset + rodata_builder_.section_.sh_size; |
| program_headers[PH_LOAD_R__].p_filesz = load_r_size; |
| program_headers[PH_LOAD_R__].p_memsz = load_r_size; |
| program_headers[PH_LOAD_R__].p_align = rodata_builder_.section_.sh_addralign; |
| |
| Elf32_Word load_rx_size = text_builder_.section_.sh_size; |
| program_headers[PH_LOAD_R_X].p_offset = text_builder_.section_.sh_offset; |
| program_headers[PH_LOAD_R_X].p_vaddr = text_builder_.section_.sh_offset; |
| program_headers[PH_LOAD_R_X].p_paddr = text_builder_.section_.sh_offset; |
| program_headers[PH_LOAD_R_X].p_filesz = load_rx_size; |
| program_headers[PH_LOAD_R_X].p_memsz = load_rx_size; |
| program_headers[PH_LOAD_R_X].p_align = text_builder_.section_.sh_addralign; |
| |
| program_headers[PH_LOAD_RW_].p_offset = dynamic_builder_.section_.sh_offset; |
| program_headers[PH_LOAD_RW_].p_vaddr = dynamic_builder_.section_.sh_offset; |
| program_headers[PH_LOAD_RW_].p_paddr = dynamic_builder_.section_.sh_offset; |
| program_headers[PH_LOAD_RW_].p_filesz = dynamic_builder_.section_.sh_size; |
| program_headers[PH_LOAD_RW_].p_memsz = dynamic_builder_.section_.sh_size; |
| program_headers[PH_LOAD_RW_].p_align = dynamic_builder_.section_.sh_addralign; |
| |
| program_headers[PH_DYNAMIC].p_offset = dynamic_builder_.section_.sh_offset; |
| program_headers[PH_DYNAMIC].p_vaddr = dynamic_builder_.section_.sh_offset; |
| program_headers[PH_DYNAMIC].p_paddr = dynamic_builder_.section_.sh_offset; |
| program_headers[PH_DYNAMIC].p_filesz = dynamic_builder_.section_.sh_size; |
| program_headers[PH_DYNAMIC].p_memsz = dynamic_builder_.section_.sh_size; |
| program_headers[PH_DYNAMIC].p_align = dynamic_builder_.section_.sh_addralign; |
| |
| // Finish setup of the Ehdr values. |
| elf_header_.e_phoff = phdr_offset; |
| elf_header_.e_shoff = sections_offset; |
| elf_header_.e_phnum = PH_NUM; |
| elf_header_.e_shnum = section_ptrs.size(); |
| elf_header_.e_shstrndx = shstrtab_builder_.section_index_; |
| |
| // Add the rest of the pieces to the list. |
| pieces.push_back(ElfFilePiece("Elf Header", 0, &elf_header_, sizeof(elf_header_))); |
| pieces.push_back(ElfFilePiece("Program headers", phdr_offset, |
| &program_headers, sizeof(program_headers))); |
| pieces.push_back(ElfFilePiece(".dynamic", dynamic_builder_.section_.sh_offset, |
| dynamic.data(), dynamic_builder_.section_.sh_size)); |
| pieces.push_back(ElfFilePiece(".dynsym", dynsym_builder_.section_.sh_offset, |
| dynsym.data(), dynsym.size() * sizeof(Elf32_Sym))); |
| pieces.push_back(ElfFilePiece(".dynstr", dynsym_builder_.strtab_.section_.sh_offset, |
| dynstr.c_str(), dynstr.size())); |
| pieces.push_back(ElfFilePiece(".hash", hash_builder_.section_.sh_offset, |
| hash.data(), hash.size() * sizeof(Elf32_Word))); |
| pieces.push_back(ElfFilePiece(".rodata", rodata_builder_.section_.sh_offset, |
| nullptr, rodata_builder_.section_.sh_size)); |
| pieces.push_back(ElfFilePiece(".text", text_builder_.section_.sh_offset, |
| nullptr, text_builder_.section_.sh_size)); |
| if (IncludingDebugSymbols()) { |
| pieces.push_back(ElfFilePiece(".symtab", symtab_builder_.section_.sh_offset, |
| symtab.data(), symtab.size() * sizeof(Elf32_Sym))); |
| pieces.push_back(ElfFilePiece(".strtab", symtab_builder_.strtab_.section_.sh_offset, |
| strtab.c_str(), strtab.size())); |
| } |
| pieces.push_back(ElfFilePiece(".shstrtab", shstrtab_builder_.section_.sh_offset, |
| &shstrtab[0], shstrtab.size())); |
| for (uint32_t i = 0; i < section_ptrs.size(); ++i) { |
| // Just add all the sections in induvidually since they are all over the |
| // place on the heap/stack. |
| Elf32_Word cur_off = sections_offset + i * sizeof(Elf32_Shdr); |
| pieces.push_back(ElfFilePiece("section table piece", cur_off, |
| section_ptrs[i], sizeof(Elf32_Shdr))); |
| } |
| |
| if (!WriteOutFile(pieces)) { |
| LOG(ERROR) << "Unable to write to file " << elf_file_->GetPath(); |
| return false; |
| } |
| // write out the actual oat file data. |
| Elf32_Word oat_data_offset = rodata_builder_.section_.sh_offset; |
| if (static_cast<off_t>(oat_data_offset) != lseek(elf_file_->Fd(), oat_data_offset, SEEK_SET)) { |
| PLOG(ERROR) << "Failed to seek to .rodata offset " << oat_data_offset |
| << " for " << elf_file_->GetPath(); |
| return false; |
| } |
| std::unique_ptr<BufferedOutputStream> output_stream( |
| new BufferedOutputStream(new FileOutputStream(elf_file_))); |
| if (!oat_writer_->Write(output_stream.get())) { |
| PLOG(ERROR) << "Failed to write .rodata and .text for " << elf_file_->GetPath(); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool ElfWriterQuick::ElfBuilder::WriteOutFile(const std::vector<ElfFilePiece>& pieces) { |
| // TODO It would be nice if this checked for overlap. |
| for (auto it = pieces.begin(); it != pieces.end(); ++it) { |
| if (it->data_) { |
| if (static_cast<off_t>(it->offset_) != lseek(elf_file_->Fd(), it->offset_, SEEK_SET)) { |
| PLOG(ERROR) << "Failed to seek to " << it->dbg_name_ << " offset location " |
| << it->offset_ << " for " << elf_file_->GetPath(); |
| return false; |
| } |
| if (!elf_file_->WriteFully(it->data_, it->size_)) { |
| PLOG(ERROR) << "Failed to write " << it->dbg_name_ << " for " << elf_file_->GetPath(); |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| void ElfWriterQuick::ElfBuilder::SetupDynamic() { |
| dynamic_builder_.AddDynamicTag(DT_HASH, 0, &hash_builder_); |
| dynamic_builder_.AddDynamicTag(DT_STRTAB, 0, &dynsym_builder_.strtab_); |
| dynamic_builder_.AddDynamicTag(DT_SYMTAB, 0, &dynsym_builder_); |
| dynamic_builder_.AddDynamicTag(DT_SYMENT, sizeof(Elf32_Sym)); |
| } |
| |
| void ElfWriterQuick::ElfBuilder::SetupRequiredSymbols() { |
| dynsym_builder_.AddSymbol("oatdata", &rodata_builder_, 0, true, |
| rodata_builder_.size_, STB_GLOBAL, STT_OBJECT); |
| dynsym_builder_.AddSymbol("oatexec", &text_builder_, 0, true, |
| text_builder_.size_, STB_GLOBAL, STT_OBJECT); |
| dynsym_builder_.AddSymbol("oatlastword", &text_builder_, text_builder_.size_ - 4, |
| true, 4, STB_GLOBAL, STT_OBJECT); |
| } |
| |
| void ElfWriterQuick::ElfDynamicBuilder::AddDynamicTag(Elf32_Sword tag, Elf32_Word d_un) { |
| if (tag == DT_NULL) { |
| return; |
| } |
| dynamics_.push_back({nullptr, tag, d_un}); |
| } |
| |
| void ElfWriterQuick::ElfDynamicBuilder::AddDynamicTag(Elf32_Sword tag, Elf32_Word d_un, |
| ElfSectionBuilder* section) { |
| if (tag == DT_NULL) { |
| return; |
| } |
| dynamics_.push_back({section, tag, d_un}); |
| } |
| |
| std::vector<Elf32_Dyn> ElfWriterQuick::ElfDynamicBuilder::GetDynamics(Elf32_Word strsz, |
| Elf32_Word soname) { |
| std::vector<Elf32_Dyn> ret; |
| for (auto it = dynamics_.cbegin(); it != dynamics_.cend(); ++it) { |
| if (it->section_) { |
| // We are adding an address relative to a section. |
| ret.push_back( |
| {it->tag_, {it->off_ + it->section_->section_.sh_addr}}); |
| } else { |
| ret.push_back({it->tag_, {it->off_}}); |
| } |
| } |
| ret.push_back({DT_STRSZ, {strsz}}); |
| ret.push_back({DT_SONAME, {soname}}); |
| ret.push_back({DT_NULL, {0}}); |
| return ret; |
| } |
| |
| std::vector<Elf32_Sym> ElfWriterQuick::ElfSymtabBuilder::GenerateSymtab() { |
| std::vector<Elf32_Sym> ret; |
| Elf32_Sym undef_sym; |
| memset(&undef_sym, 0, sizeof(undef_sym)); |
| undef_sym.st_shndx = SHN_UNDEF; |
| ret.push_back(undef_sym); |
| |
| for (auto it = symbols_.cbegin(); it != symbols_.cend(); ++it) { |
| Elf32_Sym sym; |
| memset(&sym, 0, sizeof(sym)); |
| sym.st_name = it->name_idx_; |
| if (it->is_relative_) { |
| sym.st_value = it->addr_ + it->section_->section_.sh_offset; |
| } else { |
| sym.st_value = it->addr_; |
| } |
| sym.st_size = it->size_; |
| sym.st_other = it->other_; |
| sym.st_shndx = it->section_->section_index_; |
| sym.st_info = it->info_; |
| |
| ret.push_back(sym); |
| } |
| return ret; |
| } |
| |
| std::string ElfWriterQuick::ElfSymtabBuilder::GenerateStrtab() { |
| std::string tab; |
| tab += '\0'; |
| for (auto it = symbols_.begin(); it != symbols_.end(); ++it) { |
| it->name_idx_ = tab.size(); |
| tab += it->name_; |
| tab += '\0'; |
| } |
| strtab_.section_.sh_size = tab.size(); |
| return tab; |
| } |
| |
| void ElfWriterQuick::ElfBuilder::AssignSectionStr( |
| ElfSectionBuilder* builder, std::string* strtab) { |
| builder->section_.sh_name = strtab->size(); |
| *strtab += builder->name_; |
| *strtab += '\0'; |
| if (debug_logging_) { |
| LOG(INFO) << "adding section name \"" << builder->name_ << "\" " |
| << "to shstrtab at offset " << builder->section_.sh_name; |
| } |
| } |
| |
| // from bionic |
| static unsigned elfhash(const char *_name) { |
| const unsigned char *name = (const unsigned char *) _name; |
| unsigned h = 0, g; |
| |
| while (*name) { |
| h = (h << 4) + *name++; |
| g = h & 0xf0000000; |
| h ^= g; |
| h ^= g >> 24; |
| } |
| return h; |
| } |
| |
| |
| std::vector<Elf32_Word> ElfWriterQuick::ElfSymtabBuilder::GenerateHashContents() { |
| // Here is how The ELF hash table works. |
| // There are 3 arrays to worry about. |
| // * The symbol table where the symbol information is. |
| // * The bucket array which is an array of indexes into the symtab and chain. |
| // * The chain array which is also an array of indexes into the symtab and chain. |
| // |
| // Lets say the state is something like this. |
| // +--------+ +--------+ +-----------+ |
| // | symtab | | bucket | | chain | |
| // | nullptr | | 1 | | STN_UNDEF | |
| // | <sym1> | | 4 | | 2 | |
| // | <sym2> | | | | 5 | |
| // | <sym3> | | | | STN_UNDEF | |
| // | <sym4> | | | | 3 | |
| // | <sym5> | | | | STN_UNDEF | |
| // +--------+ +--------+ +-----------+ |
| // |
| // The lookup process (in python psudocode) is |
| // |
| // def GetSym(name): |
| // # NB STN_UNDEF == 0 |
| // indx = bucket[elfhash(name) % num_buckets] |
| // while indx != STN_UNDEF: |
| // if GetSymbolName(symtab[indx]) == name: |
| // return symtab[indx] |
| // indx = chain[indx] |
| // return SYMBOL_NOT_FOUND |
| // |
| // Between bucket and chain arrays every symtab index must be present exactly |
| // once (except for STN_UNDEF, which must be present 1 + num_bucket times). |
| |
| // Select number of buckets. |
| // This is essentially arbitrary. |
| Elf32_Word nbuckets; |
| Elf32_Word chain_size = GetSize(); |
| if (symbols_.size() < 8) { |
| nbuckets = 2; |
| } else if (symbols_.size() < 32) { |
| nbuckets = 4; |
| } else if (symbols_.size() < 256) { |
| nbuckets = 16; |
| } else { |
| // Have about 32 ids per bucket. |
| nbuckets = RoundUp(symbols_.size()/32, 2); |
| } |
| std::vector<Elf32_Word> hash; |
| hash.push_back(nbuckets); |
| hash.push_back(chain_size); |
| uint32_t bucket_offset = hash.size(); |
| uint32_t chain_offset = bucket_offset + nbuckets; |
| hash.resize(hash.size() + nbuckets + chain_size, 0); |
| |
| Elf32_Word* buckets = hash.data() + bucket_offset; |
| Elf32_Word* chain = hash.data() + chain_offset; |
| |
| // Set up the actual hash table. |
| for (Elf32_Word i = 0; i < symbols_.size(); i++) { |
| // Add 1 since we need to have the null symbol that is not in the symbols |
| // list. |
| Elf32_Word index = i + 1; |
| Elf32_Word hash_val = static_cast<Elf32_Word>(elfhash(symbols_[i].name_.c_str())) % nbuckets; |
| if (buckets[hash_val] == 0) { |
| buckets[hash_val] = index; |
| } else { |
| hash_val = buckets[hash_val]; |
| CHECK_LT(hash_val, chain_size); |
| while (chain[hash_val] != 0) { |
| hash_val = chain[hash_val]; |
| CHECK_LT(hash_val, chain_size); |
| } |
| chain[hash_val] = index; |
| // Check for loops. Works because if this is non-empty then there must be |
| // another cell which already contains the same symbol index as this one, |
| // which means some symbol has more then one name, which isn't allowed. |
| CHECK_EQ(chain[index], static_cast<Elf32_Word>(0)); |
| } |
| } |
| |
| return hash; |
| } |
| |
| void ElfWriterQuick::ElfBuilder::SetupEhdr() { |
| memset(&elf_header_, 0, sizeof(elf_header_)); |
| elf_header_.e_ident[EI_MAG0] = ELFMAG0; |
| elf_header_.e_ident[EI_MAG1] = ELFMAG1; |
| elf_header_.e_ident[EI_MAG2] = ELFMAG2; |
| elf_header_.e_ident[EI_MAG3] = ELFMAG3; |
| elf_header_.e_ident[EI_CLASS] = ELFCLASS32; |
| elf_header_.e_ident[EI_DATA] = ELFDATA2LSB; |
| elf_header_.e_ident[EI_VERSION] = EV_CURRENT; |
| elf_header_.e_ident[EI_OSABI] = ELFOSABI_LINUX; |
| elf_header_.e_ident[EI_ABIVERSION] = 0; |
| elf_header_.e_type = ET_DYN; |
| elf_header_.e_version = 1; |
| elf_header_.e_entry = 0; |
| elf_header_.e_ehsize = sizeof(Elf32_Ehdr); |
| elf_header_.e_phentsize = sizeof(Elf32_Phdr); |
| elf_header_.e_shentsize = sizeof(Elf32_Shdr); |
| elf_header_.e_phoff = sizeof(Elf32_Ehdr); |
| } |
| |
| void ElfWriterQuick::ElfBuilder::SetISA(InstructionSet isa) { |
| switch (isa) { |
| case kArm: |
| // Fall through. |
| case kThumb2: { |
| elf_header_.e_machine = EM_ARM; |
| elf_header_.e_flags = EF_ARM_EABI_VER5; |
| break; |
| } |
| case kArm64: { |
| elf_header_.e_machine = EM_AARCH64; |
| elf_header_.e_flags = 0; |
| break; |
| } |
| case kX86: { |
| elf_header_.e_machine = EM_386; |
| elf_header_.e_flags = 0; |
| break; |
| } |
| case kX86_64: { |
| elf_header_.e_machine = EM_X86_64; |
| elf_header_.e_flags = 0; |
| break; |
| } |
| case kMips: { |
| elf_header_.e_machine = EM_MIPS; |
| elf_header_.e_flags = (EF_MIPS_NOREORDER | |
| EF_MIPS_PIC | |
| EF_MIPS_CPIC | |
| EF_MIPS_ABI_O32 | |
| EF_MIPS_ARCH_32R2); |
| break; |
| } |
| default: { |
| fatal_error_ = true; |
| LOG(FATAL) << "Unknown instruction set: " << isa; |
| break; |
| } |
| } |
| } |
| |
| void ElfWriterQuick::ElfSymtabBuilder::AddSymbol( |
| const std::string& name, const ElfSectionBuilder* section, Elf32_Addr addr, |
| bool is_relative, Elf32_Word size, uint8_t binding, uint8_t type, uint8_t other) { |
| CHECK(section); |
| ElfSymtabBuilder::ElfSymbolState state {name, section, addr, size, is_relative, |
| MakeStInfo(binding, type), other, 0}; |
| symbols_.push_back(state); |
| } |
| |
| bool ElfWriterQuick::Create(File* elf_file, |
| OatWriter* oat_writer, |
| const std::vector<const DexFile*>& dex_files, |
| const std::string& android_root, |
| bool is_host, |
| const CompilerDriver& driver) { |
| ElfWriterQuick elf_writer(driver, elf_file); |
| return elf_writer.Write(oat_writer, dex_files, android_root, is_host); |
| } |
| |
| // Add patch information to this section. Each patch is a Elf32_Word that |
| // identifies an offset from the start of the text section |
| void ElfWriterQuick::ReservePatchSpace(std::vector<uint8_t>* buffer, bool debug) { |
| size_t size = |
| compiler_driver_->GetCodeToPatch().size() + |
| compiler_driver_->GetMethodsToPatch().size() + |
| compiler_driver_->GetClassesToPatch().size(); |
| if (size == 0) { |
| if (debug) { |
| LOG(INFO) << "No patches to record"; |
| } |
| return; |
| } |
| buffer->resize(size * sizeof(uintptr_t)); |
| if (debug) { |
| LOG(INFO) << "Patches reserved for " << size; |
| } |
| } |
| |
| bool ElfWriterQuick::Write(OatWriter* oat_writer, |
| const std::vector<const DexFile*>& dex_files_unused, |
| const std::string& android_root_unused, |
| bool is_host_unused) { |
| const bool debug = false; |
| const bool add_symbols = oat_writer->DidAddSymbols(); |
| const OatHeader& oat_header = oat_writer->GetOatHeader(); |
| Elf32_Word oat_data_size = oat_header.GetExecutableOffset(); |
| uint32_t oat_exec_size = oat_writer->GetSize() - oat_data_size; |
| |
| ElfBuilder builder(oat_writer, elf_file_, compiler_driver_->GetInstructionSet(), 0, |
| oat_data_size, oat_data_size, oat_exec_size, add_symbols, debug); |
| |
| if (add_symbols) { |
| AddDebugSymbols(builder, oat_writer, debug); |
| } |
| |
| bool generateDebugInformation = compiler_driver_->GetCallFrameInformation() != nullptr; |
| if (generateDebugInformation) { |
| ElfRawSectionBuilder debug_info(".debug_info", SHT_PROGBITS, 0, nullptr, 0, 1, 0); |
| ElfRawSectionBuilder debug_abbrev(".debug_abbrev", SHT_PROGBITS, 0, nullptr, 0, 1, 0); |
| ElfRawSectionBuilder debug_str(".debug_str", SHT_PROGBITS, 0, nullptr, 0, 1, 0); |
| ElfRawSectionBuilder eh_frame(".eh_frame", SHT_PROGBITS, SHF_ALLOC, nullptr, 0, 4, 0); |
| eh_frame.SetBuffer(*compiler_driver_->GetCallFrameInformation()); |
| |
| FillInCFIInformation(oat_writer, debug_info.GetBuffer(), |
| debug_abbrev.GetBuffer(), debug_str.GetBuffer()); |
| builder.RegisterRawSection(debug_info); |
| builder.RegisterRawSection(debug_abbrev); |
| builder.RegisterRawSection(eh_frame); |
| builder.RegisterRawSection(debug_str); |
| } |
| |
| if (compiler_driver_->GetCompilerOptions().GetIncludePatchInformation()) { |
| ElfRawSectionBuilder oat_patches(".oat_patches", SHT_OAT_PATCH, 0, NULL, 0, |
| sizeof(size_t), sizeof(size_t)); |
| ReservePatchSpace(oat_patches.GetBuffer(), debug); |
| builder.RegisterRawSection(oat_patches); |
| } |
| |
| return builder.Write(); |
| } |
| |
| void ElfWriterQuick::AddDebugSymbols(ElfBuilder& builder, OatWriter* oat_writer, bool debug) { |
| const std::vector<OatWriter::DebugInfo>& method_info = oat_writer->GetCFIMethodInfo(); |
| ElfSymtabBuilder* symtab = &builder.symtab_builder_; |
| for (auto it = method_info.begin(); it != method_info.end(); ++it) { |
| symtab->AddSymbol(it->method_name_, &builder.text_builder_, it->low_pc_, true, |
| it->high_pc_ - it->low_pc_, STB_GLOBAL, STT_FUNC); |
| } |
| } |
| |
| static void UpdateWord(std::vector<uint8_t>*buf, int offset, int data) { |
| (*buf)[offset+0] = data; |
| (*buf)[offset+1] = data >> 8; |
| (*buf)[offset+2] = data >> 16; |
| (*buf)[offset+3] = data >> 24; |
| } |
| |
| static void PushWord(std::vector<uint8_t>*buf, int data) { |
| buf->push_back(data & 0xff); |
| buf->push_back((data >> 8) & 0xff); |
| buf->push_back((data >> 16) & 0xff); |
| buf->push_back((data >> 24) & 0xff); |
| } |
| |
| static void PushHalf(std::vector<uint8_t>*buf, int data) { |
| buf->push_back(data & 0xff); |
| buf->push_back((data >> 8) & 0xff); |
| } |
| |
| void ElfWriterQuick::FillInCFIInformation(OatWriter* oat_writer, |
| std::vector<uint8_t>* dbg_info, |
| std::vector<uint8_t>* dbg_abbrev, |
| std::vector<uint8_t>* dbg_str) { |
| // Create the debug_abbrev section with boilerplate information. |
| // We only care about low_pc and high_pc right now for the compilation |
| // unit and methods. |
| |
| // Tag 1: Compilation unit: DW_TAG_compile_unit. |
| dbg_abbrev->push_back(1); |
| dbg_abbrev->push_back(DW_TAG_compile_unit); |
| |
| // There are children (the methods). |
| dbg_abbrev->push_back(DW_CHILDREN_yes); |
| |
| // DW_LANG_Java DW_FORM_data1. |
| dbg_abbrev->push_back(DW_AT_language); |
| dbg_abbrev->push_back(DW_FORM_data1); |
| |
| // DW_AT_low_pc DW_FORM_addr. |
| dbg_abbrev->push_back(DW_AT_low_pc); |
| dbg_abbrev->push_back(DW_FORM_addr); |
| |
| // DW_AT_high_pc DW_FORM_addr. |
| dbg_abbrev->push_back(DW_AT_high_pc); |
| dbg_abbrev->push_back(DW_FORM_addr); |
| |
| // End of DW_TAG_compile_unit. |
| PushHalf(dbg_abbrev, 0); |
| |
| // Tag 2: Compilation unit: DW_TAG_subprogram. |
| dbg_abbrev->push_back(2); |
| dbg_abbrev->push_back(DW_TAG_subprogram); |
| |
| // There are no children. |
| dbg_abbrev->push_back(DW_CHILDREN_no); |
| |
| // Name of the method. |
| dbg_abbrev->push_back(DW_AT_name); |
| dbg_abbrev->push_back(DW_FORM_strp); |
| |
| // DW_AT_low_pc DW_FORM_addr. |
| dbg_abbrev->push_back(DW_AT_low_pc); |
| dbg_abbrev->push_back(DW_FORM_addr); |
| |
| // DW_AT_high_pc DW_FORM_addr. |
| dbg_abbrev->push_back(DW_AT_high_pc); |
| dbg_abbrev->push_back(DW_FORM_addr); |
| |
| // End of DW_TAG_subprogram. |
| PushHalf(dbg_abbrev, 0); |
| |
| // Start the debug_info section with the header information |
| // 'unit_length' will be filled in later. |
| PushWord(dbg_info, 0); |
| |
| // 'version' - 3. |
| PushHalf(dbg_info, 3); |
| |
| // Offset into .debug_abbrev section (always 0). |
| PushWord(dbg_info, 0); |
| |
| // Address size: 4. |
| dbg_info->push_back(4); |
| |
| // Start the description for the compilation unit. |
| // This uses tag 1. |
| dbg_info->push_back(1); |
| |
| // The language is Java. |
| dbg_info->push_back(DW_LANG_Java); |
| |
| // Leave space for low_pc and high_pc. |
| int low_pc_offset = dbg_info->size(); |
| PushWord(dbg_info, 0); |
| PushWord(dbg_info, 0); |
| |
| // Walk through the information in the method table, and enter into dbg_info. |
| const std::vector<OatWriter::DebugInfo>& dbg = oat_writer->GetCFIMethodInfo(); |
| uint32_t low_pc = 0xFFFFFFFFU; |
| uint32_t high_pc = 0; |
| |
| for (uint32_t i = 0; i < dbg.size(); i++) { |
| const OatWriter::DebugInfo& info = dbg[i]; |
| if (info.low_pc_ < low_pc) { |
| low_pc = info.low_pc_; |
| } |
| if (info.high_pc_ > high_pc) { |
| high_pc = info.high_pc_; |
| } |
| |
| // Start a new TAG: subroutine (2). |
| dbg_info->push_back(2); |
| |
| // Enter the name into the string table (and NUL terminate). |
| uint32_t str_offset = dbg_str->size(); |
| dbg_str->insert(dbg_str->end(), info.method_name_.begin(), info.method_name_.end()); |
| dbg_str->push_back('\0'); |
| |
| // Enter name, low_pc, high_pc. |
| PushWord(dbg_info, str_offset); |
| PushWord(dbg_info, info.low_pc_); |
| PushWord(dbg_info, info.high_pc_); |
| } |
| |
| // One byte terminator |
| dbg_info->push_back(0); |
| |
| // We have now walked all the methods. Fill in lengths and low/high PCs. |
| UpdateWord(dbg_info, 0, dbg_info->size() - 4); |
| UpdateWord(dbg_info, low_pc_offset, low_pc); |
| UpdateWord(dbg_info, low_pc_offset + 4, high_pc); |
| } |
| |
| } // namespace art |
