Refactor BasicElf synth_elf unitest

A=Mike Hommey <mh@glandium.org>
R=ted at https://breakpad.appspot.com/544002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1141 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/common/linux/synth_elf.cc

@@ -20,6 +20,7 @@ ELF::ELF(uint16_t machine,
   : Section(endianness),
     addr_size_(file_class == ELFCLASS64 ? 8 : 4),
     program_count_(0),
+    program_header_table_(endianness),
     section_count_(0),
     section_header_table_(endianness),
     section_header_strings_(endianness) {
@@ -115,7 +116,8 @@ int ELF::AddSection(const string& name, const Section& section,
     // sh_entsize
     .Append(endianness(), addr_size_, entsize);
 
-  sections_.push_back(ElfSection(section, type, offset, offset_label));
+  sections_.push_back(ElfSection(section, type, addr, offset, offset_label,
+                                 size));
   return index;
 }
 
@@ -133,6 +135,58 @@ void ELF::AppendSection(ElfSection &section) {
   }
 }
 
+void ELF::AddSegment(int start, int end, uint32_t type, uint32_t flags) {
+  assert(start > 0);
+  assert(size_t(start) < sections_.size());
+  assert(end > 0);
+  assert(size_t(end) < sections_.size());
+  ++program_count_;
+
+  // p_type
+  program_header_table_.D32(type);
+
+  if (addr_size_ == 8) {
+    // p_flags
+    program_header_table_.D32(flags);
+  }
+
+  size_t filesz = 0;
+  size_t memsz = 0;
+  bool prev_was_nobits = false;
+  for (int i = start; i <= end; ++i) {
+    size_t size = sections_[i].size_;
+    if (sections_[i].type_ != SHT_NOBITS) {
+      assert(!prev_was_nobits);
+      // non SHT_NOBITS sections are 4-byte aligned (see AddSection)
+      size = (size + 3) & ~3;
+      filesz += size;
+    } else {
+      prev_was_nobits = true;
+    }
+    memsz += size;
+  }
+
+  program_header_table_
+    // p_offset
+    .Append(endianness(), addr_size_, sections_[start].offset_label_)
+    // p_vaddr
+    .Append(endianness(), addr_size_, sections_[start].addr_)
+    // p_paddr
+    .Append(endianness(), addr_size_, sections_[start].addr_)
+    // p_filesz
+    .Append(endianness(), addr_size_, filesz)
+    // p_memsz
+    .Append(endianness(), addr_size_, memsz);
+
+  if (addr_size_ == 4) {
+    // p_flags
+    program_header_table_.D32(flags);
+  }
+
+  // p_align
+  program_header_table_.Append(endianness(), addr_size_, 0);
+}
+
 void ELF::Finish() {
   // Add the section header string table at the end.
   section_header_string_index_ = section_count_;
@@ -140,14 +194,19 @@ void ELF::Finish() {
   AddSection(".shstrtab", section_header_strings_, SHT_STRTAB);
   //printf("section_count_: %ld, sections_.size(): %ld\n",
   //     section_count_, sections_.size());
+  if (program_count_) {
+    Mark(&program_header_label_);
+    Append(program_header_table_);
+  } else {
+    program_header_label_ = 0;
+  }
+
   for (vector<ElfSection>::iterator it = sections_.begin();
        it < sections_.end(); ++it) {
     AppendSection(*it);
   }
   section_count_label_ = section_count_;
   program_count_label_ = program_count_;
-  // TODO:  allow adding entries to program header table
-  program_header_label_ = 0;
 
   // Section header table starts here.
   Mark(&section_header_label_);

src/common/linux/synth_elf.h

@@ -104,6 +104,10 @@ class ELF : public Section {
                  uint32_t type, uint32_t flags = 0, uint64_t addr = 0,
                  uint32_t link = 0, uint64_t entsize = 0, uint64_t offset = 0);
                   
+  // Add a segment containing from section index start to section index end.
+  // The indexes must have been gotten from AddSection.
+  void AddSegment(int start, int end, uint32_t type, uint32_t flags = 0);
+
   // Write out all data. GetContents may be used after this.
   void Finish();
 
@@ -116,6 +120,8 @@ class ELF : public Section {
   // Number of entries in the program header table.
   int program_count_;
   Label program_count_label_;
+  // The program header table itself.
+  Section program_header_table_;
 
   // Offset to the section header table.
   Label section_header_label_;
@@ -133,15 +139,17 @@ class ELF : public Section {
 
   // Record of an added section
   struct ElfSection : public Section {
-    ElfSection(const Section& section, uint32_t type, uint32_t offset,
+    ElfSection(const Section& section, uint32_t type, uint32_t addr,
-               Label offset_label)
+               uint32_t offset, Label offset_label, uint32_t size)
-    : Section(section), type_(type), offset_(offset)
+    : Section(section), type_(type), addr_(addr), offset_(offset)
-    , offset_label_(offset_label) {
+    , offset_label_(offset_label), size_(size) {
     }
 
     uint32_t type_;
+    uint32_t addr_;
     uint32_t offset_;
     Label offset_label_;
+    uint32_t size_;
   };
 
   vector<ElfSection> sections_;

src/common/linux/synth_elf_unittest.cc

@@ -42,6 +42,7 @@
 using google_breakpad::ElfClass32;
 using google_breakpad::ElfClass64;
 using google_breakpad::synth_elf::ELF;
+using google_breakpad::synth_elf::Section;
 using google_breakpad::synth_elf::StringTable;
 using google_breakpad::synth_elf::SymbolTable;
 using google_breakpad::test_assembler::Endianness;
@@ -260,4 +261,112 @@ TYPED_TEST(BasicElf, EmptyLE) {
   EXPECT_EQ(0U, shdr[1].sh_entsize);
 }
 
+TYPED_TEST(BasicElf, BasicLE) {
+  typedef typename TypeParam::Ehdr Ehdr;
+  typedef typename TypeParam::Phdr Phdr;
+  typedef typename TypeParam::Shdr Shdr;
+  const size_t kStringTableSize = sizeof("\0.text\0.bss\0.shstrtab");
+  const size_t kStringTableAlign = 4 - kStringTableSize % 4;
+  const size_t kExpectedSize = sizeof(Ehdr) +
+    // Four sections, SHT_NULL + the section header string table +
+    // 4096 bytes of the size-aligned .text section + one program header.
+    sizeof(Phdr) + 4 * sizeof(Shdr) + 4096 +
+    kStringTableSize + kStringTableAlign;
+
+  // It doesn't really matter that the machine type is right for the class.
+  ELF elf(EM_386, TypeParam::kClass, kLittleEndian);
+  Section text(kLittleEndian);
+  text.Append(4094, 0);
+  int text_idx = elf.AddSection(".text", text, SHT_PROGBITS);
+  Section bss(kLittleEndian);
+  bss.Append(16, 0);
+  int bss_idx = elf.AddSection(".bss", bss, SHT_NOBITS);
+  elf.AddSegment(text_idx, bss_idx, PT_LOAD);
+  elf.Finish();
+  EXPECT_EQ(kExpectedSize, elf.Size());
+
+  string contents;
+  ASSERT_TRUE(elf.GetContents(&contents));
+  ASSERT_EQ(kExpectedSize, contents.size());
+  const Ehdr* header =
+    reinterpret_cast<const Ehdr*>(contents.data());
+  const uint8_t kIdent[] = {
+    ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3,
+    TypeParam::kClass, ELFDATA2LSB, EV_CURRENT, ELFOSABI_SYSV,
+    0, 0, 0, 0, 0, 0, 0, 0
+  };
+  EXPECT_EQ(0, memcmp(kIdent, header->e_ident, sizeof(kIdent)));
+  EXPECT_EQ(ET_EXEC, header->e_type);
+  EXPECT_EQ(EM_386, header->e_machine);
+  EXPECT_EQ(static_cast<unsigned int>(EV_CURRENT), header->e_version);
+  EXPECT_EQ(0U, header->e_entry);
+  EXPECT_EQ(sizeof(Ehdr), header->e_phoff);
+  EXPECT_EQ(sizeof(Ehdr) + sizeof(Phdr) + 4096 + kStringTableSize +
+            kStringTableAlign, header->e_shoff);
+  EXPECT_EQ(0U, header->e_flags);
+  EXPECT_EQ(sizeof(Ehdr), header->e_ehsize);
+  EXPECT_EQ(sizeof(Phdr), header->e_phentsize);
+  EXPECT_EQ(1, header->e_phnum);
+  EXPECT_EQ(sizeof(Shdr), header->e_shentsize);
+  EXPECT_EQ(4, header->e_shnum);
+  EXPECT_EQ(3, header->e_shstrndx);
+
+  const Shdr* shdr =
+    reinterpret_cast<const Shdr*>(contents.data() + header->e_shoff);
+  EXPECT_EQ(0U, shdr[0].sh_name);
+  EXPECT_EQ(static_cast<unsigned int>(SHT_NULL), shdr[0].sh_type);
+  EXPECT_EQ(0U, shdr[0].sh_flags);
+  EXPECT_EQ(0U, shdr[0].sh_addr);
+  EXPECT_EQ(0U, shdr[0].sh_offset);
+  EXPECT_EQ(0U, shdr[0].sh_size);
+  EXPECT_EQ(0U, shdr[0].sh_link);
+  EXPECT_EQ(0U, shdr[0].sh_info);
+  EXPECT_EQ(0U, shdr[0].sh_addralign);
+  EXPECT_EQ(0U, shdr[0].sh_entsize);
+
+  EXPECT_EQ(1U, shdr[1].sh_name);
+  EXPECT_EQ(static_cast<unsigned int>(SHT_PROGBITS), shdr[1].sh_type);
+  EXPECT_EQ(0U, shdr[1].sh_flags);
+  EXPECT_EQ(0U, shdr[1].sh_addr);
+  EXPECT_EQ(sizeof(Ehdr) + sizeof(Phdr), shdr[1].sh_offset);
+  EXPECT_EQ(4094U, shdr[1].sh_size);
+  EXPECT_EQ(0U, shdr[1].sh_link);
+  EXPECT_EQ(0U, shdr[1].sh_info);
+  EXPECT_EQ(0U, shdr[1].sh_addralign);
+  EXPECT_EQ(0U, shdr[1].sh_entsize);
+
+  EXPECT_EQ(sizeof("\0.text"), shdr[2].sh_name);
+  EXPECT_EQ(static_cast<unsigned int>(SHT_NOBITS), shdr[2].sh_type);
+  EXPECT_EQ(0U, shdr[2].sh_flags);
+  EXPECT_EQ(0U, shdr[2].sh_addr);
+  EXPECT_EQ(0U, shdr[2].sh_offset);
+  EXPECT_EQ(16U, shdr[2].sh_size);
+  EXPECT_EQ(0U, shdr[2].sh_link);
+  EXPECT_EQ(0U, shdr[2].sh_info);
+  EXPECT_EQ(0U, shdr[2].sh_addralign);
+  EXPECT_EQ(0U, shdr[2].sh_entsize);
+
+  EXPECT_EQ(sizeof("\0.text\0.bss"), shdr[3].sh_name);
+  EXPECT_EQ(static_cast<unsigned int>(SHT_STRTAB), shdr[3].sh_type);
+  EXPECT_EQ(0U, shdr[3].sh_flags);
+  EXPECT_EQ(0U, shdr[3].sh_addr);
+  EXPECT_EQ(sizeof(Ehdr) + sizeof(Phdr) + 4096, shdr[3].sh_offset);
+  EXPECT_EQ(kStringTableSize, shdr[3].sh_size);
+  EXPECT_EQ(0U, shdr[3].sh_link);
+  EXPECT_EQ(0U, shdr[3].sh_info);
+  EXPECT_EQ(0U, shdr[3].sh_addralign);
+  EXPECT_EQ(0U, shdr[3].sh_entsize);
+
+  const Phdr* phdr =
+    reinterpret_cast<const Phdr*>(contents.data() + header->e_phoff);
+  EXPECT_EQ(static_cast<unsigned int>(PT_LOAD), phdr->p_type);
+  EXPECT_EQ(sizeof(Ehdr) + sizeof(Phdr), phdr->p_offset);
+  EXPECT_EQ(0U, phdr->p_vaddr);
+  EXPECT_EQ(0U, phdr->p_paddr);
+  EXPECT_EQ(4096U, phdr->p_filesz);
+  EXPECT_EQ(4096U + 16U, phdr->p_memsz);
+  EXPECT_EQ(0U, phdr->p_flags);
+  EXPECT_EQ(0U, phdr->p_align);
+}
+
 #endif  // defined(__i386__) || defined(__x86_64__)