1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/toolkit/crashreporter/google-breakpad/src/common/linux/synth_elf.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,264 @@
1.4 +#include "common/linux/synth_elf.h"
1.5 +
1.6 +#include <assert.h>
1.7 +#include <elf.h>
1.8 +#include <stdio.h>
1.9 +#include <string.h>
1.10 +
1.11 +#include "common/using_std_string.h"
1.12 +
1.13 +namespace google_breakpad {
1.14 +namespace synth_elf {
1.15 +
1.16 +#ifndef NT_GNU_BUILD_ID
1.17 +#define NT_GNU_BUILD_ID 3
1.18 +#endif
1.19 +
1.20 +ELF::ELF(uint16_t machine,
1.21 + uint8_t file_class,
1.22 + Endianness endianness)
1.23 + : Section(endianness),
1.24 + addr_size_(file_class == ELFCLASS64 ? 8 : 4),
1.25 + program_count_(0),
1.26 + program_header_table_(endianness),
1.27 + section_count_(0),
1.28 + section_header_table_(endianness),
1.29 + section_header_strings_(endianness) {
1.30 + // Could add support for more machine types here if needed.
1.31 + assert(machine == EM_386 ||
1.32 + machine == EM_X86_64 ||
1.33 + machine == EM_ARM);
1.34 + assert(file_class == ELFCLASS32 || file_class == ELFCLASS64);
1.35 +
1.36 + start() = 0;
1.37 + // Add ELF header
1.38 + // e_ident
1.39 + // EI_MAG0...EI_MAG3
1.40 + D8(ELFMAG0);
1.41 + D8(ELFMAG1);
1.42 + D8(ELFMAG2);
1.43 + D8(ELFMAG3);
1.44 + // EI_CLASS
1.45 + D8(file_class);
1.46 + // EI_DATA
1.47 + D8(endianness == kLittleEndian ? ELFDATA2LSB : ELFDATA2MSB);
1.48 + // EI_VERSION
1.49 + D8(EV_CURRENT);
1.50 + // EI_OSABI
1.51 + D8(ELFOSABI_SYSV);
1.52 + // EI_ABIVERSION
1.53 + D8(0);
1.54 + // EI_PAD
1.55 + Append(7, 0);
1.56 + assert(Size() == EI_NIDENT);
1.57 +
1.58 + // e_type
1.59 + D16(ET_EXEC); //TODO: allow passing ET_DYN?
1.60 + // e_machine
1.61 + D16(machine);
1.62 + // e_version
1.63 + D32(EV_CURRENT);
1.64 + // e_entry
1.65 + Append(endianness, addr_size_, 0);
1.66 + // e_phoff
1.67 + Append(endianness, addr_size_, program_header_label_);
1.68 + // e_shoff
1.69 + Append(endianness, addr_size_, section_header_label_);
1.70 + // e_flags
1.71 + D32(0);
1.72 + // e_ehsize
1.73 + D16(addr_size_ == 8 ? sizeof(Elf64_Ehdr) : sizeof(Elf32_Ehdr));
1.74 + // e_phentsize
1.75 + D16(addr_size_ == 8 ? sizeof(Elf64_Phdr) : sizeof(Elf32_Phdr));
1.76 + // e_phnum
1.77 + D16(program_count_label_);
1.78 + // e_shentsize
1.79 + D16(addr_size_ == 8 ? sizeof(Elf64_Shdr) : sizeof(Elf32_Shdr));
1.80 + // e_shnum
1.81 + D16(section_count_label_);
1.82 + // e_shstrndx
1.83 + D16(section_header_string_index_);
1.84 +
1.85 + // Add an empty section for SHN_UNDEF.
1.86 + Section shn_undef;
1.87 + AddSection("", shn_undef, SHT_NULL);
1.88 +}
1.89 +
1.90 +int ELF::AddSection(const string& name, const Section& section,
1.91 + uint32_t type, uint32_t flags, uint64_t addr,
1.92 + uint32_t link, uint64_t entsize, uint64_t offset) {
1.93 + Label offset_label;
1.94 + Label string_label(section_header_strings_.Add(name));
1.95 + size_t size = section.Size();
1.96 +
1.97 + int index = section_count_;
1.98 + ++section_count_;
1.99 +
1.100 + section_header_table_
1.101 + // sh_name
1.102 + .D32(string_label)
1.103 + // sh_type
1.104 + .D32(type)
1.105 + // sh_flags
1.106 + .Append(endianness(), addr_size_, flags)
1.107 + // sh_addr
1.108 + .Append(endianness(), addr_size_, addr)
1.109 + // sh_offset
1.110 + .Append(endianness(), addr_size_, offset_label)
1.111 + // sh_size
1.112 + .Append(endianness(), addr_size_, size)
1.113 + // sh_link
1.114 + .D32(link)
1.115 + // sh_info
1.116 + .D32(0)
1.117 + // sh_addralign
1.118 + .Append(endianness(), addr_size_, 0)
1.119 + // sh_entsize
1.120 + .Append(endianness(), addr_size_, entsize);
1.121 +
1.122 + sections_.push_back(ElfSection(section, type, addr, offset, offset_label,
1.123 + size));
1.124 + return index;
1.125 +}
1.126 +
1.127 +void ELF::AppendSection(ElfSection §ion) {
1.128 + // NULL and NOBITS sections have no content, so they
1.129 + // don't need to be written to the file.
1.130 + if (section.type_ == SHT_NULL) {
1.131 + section.offset_label_ = 0;
1.132 + } else if (section.type_ == SHT_NOBITS) {
1.133 + section.offset_label_ = section.offset_;
1.134 + } else {
1.135 + Mark(§ion.offset_label_);
1.136 + Append(section);
1.137 + Align(4);
1.138 + }
1.139 +}
1.140 +
1.141 +void ELF::AddSegment(int start, int end, uint32_t type, uint32_t flags) {
1.142 + assert(start > 0);
1.143 + assert(size_t(start) < sections_.size());
1.144 + assert(end > 0);
1.145 + assert(size_t(end) < sections_.size());
1.146 + ++program_count_;
1.147 +
1.148 + // p_type
1.149 + program_header_table_.D32(type);
1.150 +
1.151 + if (addr_size_ == 8) {
1.152 + // p_flags
1.153 + program_header_table_.D32(flags);
1.154 + }
1.155 +
1.156 + size_t filesz = 0;
1.157 + size_t memsz = 0;
1.158 + bool prev_was_nobits = false;
1.159 + for (int i = start; i <= end; ++i) {
1.160 + size_t size = sections_[i].size_;
1.161 + if (sections_[i].type_ != SHT_NOBITS) {
1.162 + assert(!prev_was_nobits);
1.163 + // non SHT_NOBITS sections are 4-byte aligned (see AddSection)
1.164 + size = (size + 3) & ~3;
1.165 + filesz += size;
1.166 + } else {
1.167 + prev_was_nobits = true;
1.168 + }
1.169 + memsz += size;
1.170 + }
1.171 +
1.172 + program_header_table_
1.173 + // p_offset
1.174 + .Append(endianness(), addr_size_, sections_[start].offset_label_)
1.175 + // p_vaddr
1.176 + .Append(endianness(), addr_size_, sections_[start].addr_)
1.177 + // p_paddr
1.178 + .Append(endianness(), addr_size_, sections_[start].addr_)
1.179 + // p_filesz
1.180 + .Append(endianness(), addr_size_, filesz)
1.181 + // p_memsz
1.182 + .Append(endianness(), addr_size_, memsz);
1.183 +
1.184 + if (addr_size_ == 4) {
1.185 + // p_flags
1.186 + program_header_table_.D32(flags);
1.187 + }
1.188 +
1.189 + // p_align
1.190 + program_header_table_.Append(endianness(), addr_size_, 0);
1.191 +}
1.192 +
1.193 +void ELF::Finish() {
1.194 + // Add the section header string table at the end.
1.195 + section_header_string_index_ = section_count_;
1.196 + //printf(".shstrtab size: %ld\n", section_header_strings_.Size());
1.197 + AddSection(".shstrtab", section_header_strings_, SHT_STRTAB);
1.198 + //printf("section_count_: %ld, sections_.size(): %ld\n",
1.199 + // section_count_, sections_.size());
1.200 + if (program_count_) {
1.201 + Mark(&program_header_label_);
1.202 + Append(program_header_table_);
1.203 + } else {
1.204 + program_header_label_ = 0;
1.205 + }
1.206 +
1.207 + for (vector<ElfSection>::iterator it = sections_.begin();
1.208 + it < sections_.end(); ++it) {
1.209 + AppendSection(*it);
1.210 + }
1.211 + section_count_label_ = section_count_;
1.212 + program_count_label_ = program_count_;
1.213 +
1.214 + // Section header table starts here.
1.215 + Mark(§ion_header_label_);
1.216 + Append(section_header_table_);
1.217 +}
1.218 +
1.219 +SymbolTable::SymbolTable(Endianness endianness,
1.220 + size_t addr_size,
1.221 + StringTable& table) : Section(endianness),
1.222 + addr_size_(addr_size),
1.223 + table_(table) {
1.224 + assert(addr_size_ == 4 || addr_size_ == 8);
1.225 +}
1.226 +
1.227 +void SymbolTable::AddSymbol(const string& name, uint32_t value,
1.228 + uint32_t size, unsigned info, uint16_t shndx) {
1.229 + assert(addr_size_ == 4);
1.230 + D32(table_.Add(name));
1.231 + D32(value);
1.232 + D32(size);
1.233 + D8(info);
1.234 + D8(0); // other
1.235 + D16(shndx);
1.236 +}
1.237 +
1.238 +void SymbolTable::AddSymbol(const string& name, uint64_t value,
1.239 + uint64_t size, unsigned info, uint16_t shndx) {
1.240 + assert(addr_size_ == 8);
1.241 + D32(table_.Add(name));
1.242 + D8(info);
1.243 + D8(0); // other
1.244 + D16(shndx);
1.245 + D64(value);
1.246 + D64(size);
1.247 +}
1.248 +
1.249 +void Notes::AddNote(int type, const string &name, const uint8_t* desc_bytes,
1.250 + size_t desc_size) {
1.251 + // Elf32_Nhdr and Elf64_Nhdr are exactly the same.
1.252 + Elf32_Nhdr note_header;
1.253 + memset(¬e_header, 0, sizeof(note_header));
1.254 + note_header.n_namesz = name.length() + 1;
1.255 + note_header.n_descsz = desc_size;
1.256 + note_header.n_type = type;
1.257 +
1.258 + Append(reinterpret_cast<const uint8_t*>(¬e_header),
1.259 + sizeof(note_header));
1.260 + AppendCString(name);
1.261 + Align(4);
1.262 + Append(desc_bytes, desc_size);
1.263 + Align(4);
1.264 +}
1.265 +
1.266 +} // namespace synth_elf
1.267 +} // namespace google_breakpad
