issue 243 - Linux dumper should use build id produced by ld --build-id if available

R=thestig at http://breakpad.appspot.com/185001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@830 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 31 insertions, 1 deletions

diff --git a/src/common/linux/synth_elf.cc b/src/common/linux/synth_elf.cc
index 8f8aad32..3e10b691 100644
--- a/src/common/linux/synth_elf.cc
+++ b/src/common/linux/synth_elf.cc
@@ -3,10 +3,15 @@
 #include <assert.h>
 #include <elf.h>
 #include <stdio.h>
+#include <string.h>
 
 namespace google_breakpad {
 namespace synth_elf {
 
+#ifndef NT_GNU_BUILD_ID
+#define NT_GNU_BUILD_ID 3
+#endif
+
 ELF::ELF(uint16_t machine,
          uint8_t file_class,
          Endianness endianness)
@@ -169,6 +174,31 @@ 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";
+  // 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;
+
+  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);
+}
+
 }  // namespace synth_elf
 }  // namespace google_breakpad
-