Get ELF dynamic symbol version information

[NobodyXu]

I want to get the dynamic symbol version information using object programmatically.

I can currently obtain it via object -T:

DYNAMIC SYMBOL TABLE:

0000000000000000      DF *UND*	0000000000000000 (GLIBC_2.17) error
0000000000000000      DF *UND*	0000000000000000 (GLIBC_2.17) fclose
0000000000000000      DF *UND*	0000000000000000 (GLIBC_2.17) fsync
0000000000000000      DF *UND*	0000000000000000 (GLIBC_2.17) nl_langinfo
0000000000000000      DF *UND*	0000000000000000 (GLIBC_2.17) malloc
0000000000000000      DO *UND*	0000000000000000 (GLIBC_2.17) optind
0000000000000000      DF *UND*	0000000000000000 (GLIBC_2.17) __fprintf_chk
0000000000000000      DF *UND*	0000000000000000 (GLIBC_2.17) sigismember

however object isn't always available and I want to do it in Rust.

I can't find a function/trait doing this and printing symbol_name alone doesn't provide me with the information required.

My goal is to find which glibc version is required for the binary.

[philipc]

Currently the only way is via gnu_verneed. Changing ElfFile::imports may be an option, but I think that will require API changes.

[NobodyXu]

Thanks that could work for me, but I don't know how to obtain a object::read::elf::SectionTable from read::ElfFile, there doesn't seem to be an API doing that.

[philipc]

Since what you are doing is simple and specific to ELF, I suggest using the low level API instead of ElfFile. Some untested code based on the readobj example:

let elf = object::elf::FileHeader64::<Endianness>::parse(data)?;
let endian = elf.endian()?;
if let Some(sections) = elf.sections(endian, data)? {
    if let Some((mut verneed, _)) = sections.gnu_verneed(endian, data)? {
        ...
    }
}

[NobodyXu]

Thank you!
BTW, is there anyway to check whether it's Elf32 or Elf64 so that?

Or simply fallback on error is enough?

[philipc]

Use FileKind::parse(data). The readobj example uses this too.