List global variables in executable

Question

How can I dump all the global variables and the address offsets in my executable?

This is on os x, app developed with xcode compiled with gcc.

Thank you

Answer 1

If Compiled to Mach-O

Either use otool or the cctools.

If Compiled to ELF

You should be able to do this with objdump and/or readelf.

I don't have a *nix system at hand here, but objdump -s -j .data should be getting you rather close enough.

Answer 2

An easy way to get a list of global variables and their offsets from an executable on macOS (original question) is to use the nm tool. Without any additional keys, it gives the variables and their offsets.

Example:

$ nm <some binary>
...
                 U __ZTVN10__cxxabiv117__class_type_infoE
                 U __ZTVN10__cxxabiv120__si_class_type_infoE
000000010006e248 s __ZTVN7testing17TestEventListenerE
000000010006e1c0 s __ZTVN7testing22EmptyTestEventListenerE
000000010006dfa8 s __ZTVN7testing31TestPartResultReporterInterfaceE
000000010006d860 S __ZTVN7testing32ScopedFakeTestPartResultReporterE
000000010006d8d8 S __ZTVN7testing4TestE
...

Check man nm for the explanation of the codes like U, s, S, etc.

---

In case you also want to look for string constants, there is another tool strings:

$ strings <some binary> -o -t x

will give you a list of string literals and their offsets.

See man strings for more details.