================
@@ -983,6 +995,44 @@ llvm::Error
ProcessElfCore::ParseThreadContextsFromNoteSegment(
}
}
+bool ProcessElfCore::IsElf(const NT_FILE_Entry entry) {
+ const uint8_t elf_header[4] = {0x7f, 0x45, 0x4c,
+ 0x46}; // ELF file begin with this 4 bytes
+ uint8_t buf[4];
+ Status error;
+ size_t byte_read = ReadMemory(entry.start, buf, 4, error);
+ if (byte_read == 4) {
+ return memcmp(elf_header, buf, 4) == 0;
+ } else {
+ return false;
+ }
+}
+
+UUID ProcessElfCore::FindBuildId(const NT_FILE_Entry entry) {
+ if (!IsElf(entry)) {
+ return UUID();
+ }
+ // Build ID is stored in the ELF file as a section named ".note.gnu.build-id"
+ uint8_t gnu_build_id_bytes[8] = {0x03, 0x00, 0x00, 0x00,
+ 0x47, 0x4e, 0x55, 0x00};
+ lldb::addr_t gnu_build_id_addr =
+ FastSearch(entry.start, entry.end, gnu_build_id_bytes, 8);
+ if (gnu_build_id_addr == LLDB_INVALID_ADDRESS) {
+ return UUID();
+ }
+ uint8_t buf[36];
+ Status error;
+ size_t byte_read = ReadMemory(gnu_build_id_addr - 8, buf, 36, error);
+ // .note.gnu.build-id starts with 04 00 00 00 {id_byte_size} 00 00 00 03 00
00
+ // 00 47 4e 55 00
+ if (byte_read == 36) {
----------------
clayborg wrote:
We should not assume there are always 36 bytes here. We should read the first 8
bytes to get the `namesz` and `descsz` entries using a DataExtractor. Then do
the right thing when decoding the UUID bytes by using the `namesz` value + 12
bytes for the `namesz`, `descsz` and `type` uint32_t fields. We should also
make sure our length isn't out of control and too big:
```
DataExtractor data(buf, sizeof(buf), GetByteOrder(), GetAddressByteSize());
lldb::offset_t offset = 0;
const uint32_t namesz = data.GetU32(&offset); // Decode the length of the note
name
const uint32_t descsz = data.GetU32(&offset); // Decode the UUID length
if (0 < uuid_length && uuid_length <= 20)
offset = 16; // Set the position to point to the UUID bytes
return UUID(llvm::ArrayRef<uint8_t>(data.GetData(12 + namesz), descsz);
}
```
https://github.com/llvm/llvm-project/pull/92078
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