readelf vs. objdump: why are both needed

linux elf objdump readelf
zr. picture zr. · Jan 23, 2012 · Viewed 13.2k times · Source

I need to learn about the ELF file layout for a project I am working on and I noticed the existence of these tools. Why do all Linux distributions include both readelf and objdump? Do these tools complement one another? When would i prefer to use one over another?

Answer

synthesizerpatel picture synthesizerpatel · Jan 23, 2012

from 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.  */

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