readwith objdump: perché sono entrambi necessari

Question

Ho bisogno di conoscere il layout del file ELF per un progetto su cui sto lavorando e ho notato l'esistenza di questi strumenti. Perché tutte le distribuzioni Linux includono sia readelf che objdump? Questi strumenti si completano a vicenda? Quando preferirei usarne uno rispetto all'altro?

Answer 1

da binutils/readelf.c:

/* The difference between readelf and objdump: 

    Both programs are capabale of displaying the contents of ELF format files, 
    so why does the binutils project have two file dumpers ? 

    The reason is that objdump sees an ELF file through a BFD filter of the 
    world; if BFD has a bug where, say, it disagrees about a machine constant 
    in e_flags, then the odds are good that it will remain internally 
    consistent. The linker sees it the BFD way, objdump sees it the BFD way, 
    GAS sees it the BFD way. There was need for a tool to go find out what 
    the file actually says. 

    This is why the readelf program does not link against the BFD library - it 
    exists as an independent program to help verify the correct working of BFD. 

    There is also the case that readelf can provide more information about an 
    ELF file than is provided by objdump. In particular it can display DWARF 
    debugging information which (at the moment) objdump cannot. */