Add proper support for embedded elf files.
- Add a method to get the max size of an elf file by reading the
section header offset + size. This will properly map an elf
file embedded into an apk, instead of just mapping in what is done
by the dynamic linker. It does assume that the section headers are
at the end of the elf file.
- Add new tests for the above functionality.
- Update the unwind_symbols tool to take an address for finding a
function instead of dumping the entire symbol table.
Bug: 23762183
Test: Unit tests pass, unwind through the camera process and verify
Test: the GoogleCamera.apk shows some function names.
Change-Id: I00c021680fe1d43b60d652bf91bbf6667d9617be
diff --git a/libunwindstack/ElfInterface.cpp b/libunwindstack/ElfInterface.cpp
index 75abc85..be4f88a 100644
--- a/libunwindstack/ElfInterface.cpp
+++ b/libunwindstack/ElfInterface.cpp
@@ -370,6 +370,22 @@
return false;
}
+// This is an estimation of the size of the elf file using the location
+// of the section headers and size. This assumes that the section headers
+// are at the end of the elf file. If the elf has a load bias, the size
+// will be too large, but this is acceptable.
+template <typename EhdrType>
+void ElfInterface::GetMaxSizeWithTemplate(Memory* memory, uint64_t* size) {
+ EhdrType ehdr;
+ if (!memory->Read(0, &ehdr, sizeof(ehdr))) {
+ return;
+ }
+ if (ehdr.e_shnum == 0) {
+ return;
+ }
+ *size = ehdr.e_shoff + ehdr.e_shentsize * ehdr.e_shnum;
+}
+
// Instantiate all of the needed template functions.
template void ElfInterface::InitHeadersWithTemplate<uint32_t>();
template void ElfInterface::InitHeadersWithTemplate<uint64_t>();
@@ -391,4 +407,7 @@
template bool ElfInterface::GetFunctionNameWithTemplate<Elf64_Sym>(uint64_t, std::string*,
uint64_t*);
+template void ElfInterface::GetMaxSizeWithTemplate<Elf32_Ehdr>(Memory*, uint64_t*);
+template void ElfInterface::GetMaxSizeWithTemplate<Elf64_Ehdr>(Memory*, uint64_t*);
+
} // namespace unwindstack