ELF64_GETEHDR(3)

📦
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, in alpine 3.22, alpine 3.23, alpine 3.24, arch rolling, centos-stream 10, centos-stream 9, debian trixie, fedora 43, fedora 44, nixos 26.05, nixpkgs unstable, opensuse-leap 16.0, ubuntu questing, ubuntu resolute, ubuntu stonking

💖 ELF64_GETEHDR — bestie edition 💖

okay so. this is a page from the Libelf Programmer's Manual, and today's main character is elf64_getehdr — the girl who pulls the ELF header out of a 64-bit ELF descriptor. she's not complicated, she's just important, and we're gonna learn her whole deal rn 🫶

✨ NAME ✨

elf64_getehdr — retrieve the ELF header for a 64-bit ELF descriptor 💅

like. that's it. that's the job. but bestie the job is load-bearing.

🌸 SYNOPSIS 🌸

the way you summon her:

#include <libelf.h>

Elf64_Ehdr *elf64_getehdr(Elf *elf);

yeah. one header, one function, one pointer argument. minimal. clean. iconic. ✨

🦋 DESCRIPTION 🦋

so elf64_getehdr retrieves the ELF header for the given 64-bit ELF descriptor elf. simple as that, no cap. 🎀

and why do we care?? because the ELF header is where all the crucial metadata about the ELF file lives. the lore. the receipts. it's giving:

  • the type
  • the machine
  • the version
  • the entry point
  • the program header table offset
  • the section header table offset

and if you want the full tea on what all of that actually means, go read elf(5) — she has the whole ELF header breakdown and she ate. 📖🔥

🧚 PARAMETERS 🧚

  • elf — pointer to the ELF descriptor from which to retrieve the ELF header. that's your in. that's the whole vibe check you gotta pass. 🍓

👑 RETURN VALUE 👑

on success? elf64_getehdr returns a pointer to the Elf64_Ehdr structure. slay. ✨

but if the ELF descriptor is invalid, or if it's simply not a 64-bit ELF — she returns NULL and sets an error code that you can go grab with elf_errno(3).

💀 so like, do NOT just dereference that pointer without checking, bestie. NULL is real and she WILL humble you. check the return value, then call elf_errno(3) if things went sideways. periodt.

🌈 SEE ALSO 🌈

the friend group, if you wanna keep reading:

🙈 REPORTING BUGS 🙈

found a bug? don't suffer in silence, tell the devs!! report bugs to <elfutils-devel@sourceware.org> or hit up https://sourceware.org/bugzilla/ 🐛🫶

okay that's the page!! this one came from Libelf, dated 2024-06-26, and it lives at ELF64_GETEHDR(3) in the manual — so next time you need the header of a 64-bit ELF, you know exactly who to call 💖✨🎀

📦 where this page comes from