Support generic Elf notes, with unit tests

A=Mike Hommey <mh@glandium.org>
R=ted at https://breakpad.appspot.com/546002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1142 4c0a9323-5329-0410-9bdc-e9ce6186880e

4 files changed, 63 insertions, 27 deletions

diff --git a/src/common/linux/file_id_unittest.cc b/src/common/linux/file_id_unittest.cc
index 7c6550b1..e2e13747 100644
--- a/src/common/linux/file_id_unittest.cc
+++ b/src/common/linux/file_id_unittest.cc
@@ -47,8 +47,8 @@ using namespace google_breakpad;
 using google_breakpad::ElfClass32;
 using google_breakpad::ElfClass64;
 using google_breakpad::SafeReadLink;
-using google_breakpad::synth_elf::BuildIDNote;
 using google_breakpad::synth_elf::ELF;
+using google_breakpad::synth_elf::Notes;
 using google_breakpad::test_assembler::kLittleEndian;
 using google_breakpad::test_assembler::Section;
 using ::testing::Types;
@@ -160,9 +160,10 @@ TYPED_TEST(FileIDTest, BuildID) {
   Section text(kLittleEndian);
   text.Append(4096, 0);
   elf.AddSection(".text", text, SHT_PROGBITS);
-  BuildIDNote::AppendSection(elf,
-                             kExpectedIdentifier,
-                             sizeof(kExpectedIdentifier));
+  Notes notes(kLittleEndian);
+  notes.AddNote(NT_GNU_BUILD_ID, "GNU", kExpectedIdentifier,
+                sizeof(kExpectedIdentifier));
+  elf.AddSection(".note.gnu.build-id", notes, SHT_NOTE);
   elf.Finish();
   this->GetElfContents(elf);
 
diff --git a/src/common/linux/synth_elf.cc b/src/common/linux/synth_elf.cc
index 1a741e55..9cd03ef8 100644
--- a/src/common/linux/synth_elf.cc
+++ b/src/common/linux/synth_elf.cc
@@ -243,30 +243,21 @@ void SymbolTable::AddSymbol(const string& name, uint64_t value,
   D64(size);
 }
 
-BuildIDNote::BuildIDNote(const uint8_t* id_bytes,
-                         size_t id_size,
-                         Endianness endianness) : Section(endianness) {
-  const char kNoteName[] = "GNU";
+void Notes::AddNote(int type, const string &name, const uint8_t* desc_bytes,
+                    size_t desc_size) {
   // Elf32_Nhdr and Elf64_Nhdr are exactly the same.
   Elf32_Nhdr note_header;
   memset(&note_header, 0, sizeof(note_header));
-  note_header.n_namesz = sizeof(kNoteName);
-  note_header.n_descsz = id_size;
-  note_header.n_type = NT_GNU_BUILD_ID;
+  note_header.n_namesz = name.length() + 1;
+  note_header.n_descsz = desc_size;
+  note_header.n_type = type;
 
   Append(reinterpret_cast<const uint8_t*>(&note_header),
          sizeof(note_header));
-  AppendCString(kNoteName);
-  Append(id_bytes, id_size);
-}
-
-// static
-void BuildIDNote::AppendSection(ELF& elf,
-                                const uint8_t* id_bytes,
-                                size_t id_size) {
-  const char kBuildIDSectionName[] = ".note.gnu.build-id";
-  BuildIDNote note(id_bytes, id_size, elf.endianness());
-  elf.AddSection(kBuildIDSectionName, note, SHT_NOTE);
+  AppendCString(name);
+  Align(4);
+  Append(desc_bytes, desc_size);
+  Align(4);
 }
 
 }  // namespace synth_elf
diff --git a/src/common/linux/synth_elf.h b/src/common/linux/synth_elf.h
index 9a6c0316..330ceae8 100644
--- a/src/common/linux/synth_elf.h
+++ b/src/common/linux/synth_elf.h
@@ -177,13 +177,16 @@ class SymbolTable : public Section {
   StringTable& table_;
 };
 
-// A class to build GNU Build ID note sections
-class BuildIDNote : public Section {
+// A class for note sections
+class Notes : public Section {
 public:
-  BuildIDNote(const uint8_t* id_bytes, size_t id_size, Endianness endianness);
+  Notes(Endianness endianness)
+  : Section(endianness) {
+  }
 
-  // Append a new Build ID note section to |elf|.
-  static void AppendSection(ELF& elf, const uint8_t* id_bytes, size_t id_size);
+  // Add a note.
+  void AddNote(int type, const string &name, const uint8_t* desc_bytes,
+               size_t desc_size);
 };
 
 }  // namespace synth_elf
diff --git a/src/common/linux/synth_elf_unittest.cc b/src/common/linux/synth_elf_unittest.cc
index 94ff5052..3715b6e6 100644
--- a/src/common/linux/synth_elf_unittest.cc
+++ b/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::Notes;
 using google_breakpad::synth_elf::Section;
 using google_breakpad::synth_elf::StringTable;
 using google_breakpad::synth_elf::SymbolTable;
@@ -369,4 +370,44 @@ TYPED_TEST(BasicElf, BasicLE) {
   EXPECT_EQ(0U, phdr->p_align);
 }
 
+class ElfNotesTest : public Test {};
+
+TEST_F(ElfNotesTest, Empty) {
+  Notes notes(kLittleEndian);
+  string contents;
+  ASSERT_TRUE(notes.GetContents(&contents));
+  EXPECT_EQ(0U, contents.size());
+}
+
+TEST_F(ElfNotesTest, Notes) {
+  Notes notes(kLittleEndian);
+  notes.AddNote(1, "Linux", reinterpret_cast<const uint8_t *>("\x42\x02\0\0"),
+                4);
+  notes.AddNote(2, "a", reinterpret_cast<const uint8_t *>("foobar"),
+                sizeof("foobar") - 1);
+
+  const uint8_t kExpectedNotesContents[] = {
+    // Note 1
+    0x06, 0x00, 0x00, 0x00, // name size, including terminating zero
+    0x04, 0x00, 0x00, 0x00, // desc size
+    0x01, 0x00, 0x00, 0x00, // type
+    'L', 'i', 'n', 'u', 'x', 0x00, 0x00, 0x00, // padded "Linux"
+    0x42, 0x02, 0x00, 0x00, // desc
+    // Note 2
+    0x02, 0x00, 0x00, 0x00, // name size
+    0x06, 0x00, 0x00, 0x00, // desc size
+    0x02, 0x00, 0x00, 0x00, // type
+    'a',  0x00, 0x00, 0x00, // padded "a"
+    'f', 'o', 'o', 'b', 'a', 'r', 0x00, 0x00, // padded "foobar"
+  };
+  const size_t kExpectedNotesSize = sizeof(kExpectedNotesContents);
+  EXPECT_EQ(kExpectedNotesSize, notes.Size());
+
+  string notes_contents;
+  ASSERT_TRUE(notes.GetContents(&notes_contents));
+  EXPECT_EQ(0, memcmp(kExpectedNotesContents,
+                      notes_contents.data(),
+                      notes_contents.size()));
+}
+
 #endif  // defined(__i386__) || defined(__x86_64__)