ELF_MEMORY(3)

🌸 ELF_MEMORY(3) 🌸

okay so bestie, welcome to the Libelf Programmer's Manual 💖 this is the page for elf_memory, and it's literally the glow-up your ELF data deserves when it's already chillin' in RAM instead of sitting in a file somewhere.

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✨ NAME ✨

elf_memory — create an ELF descriptor from a memory buffer 🧚

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🦋 SYNOPSIS 🦋

#include <libelf.h>

Elf * elf_memory(char *" image , size_t size );

(yes, that's exactly how it's written up there in the original, no cap, we do not touch the code 💅)

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💜 DESCRIPTION 💜

So elf_memory() makes you a brand new ELF descriptor, sourced straight from a memory region that's holding an ELF object. You reach for this one when the ELF data is already in memory and you're not about to go read it from a file descriptor like some kind of peasant. Iconic behavior honestly. 👑

The memory that image points at must contain a complete ELF file or archive. And — this is the important part, bestie, underline it twice — those contents have to stay valid and unmodified for the whole lifetime of the resulting ELF descriptor. No take-backs, no sneaky edits, periodt. 🚫

The descriptor you get back from elf_memory() is opened in read-only mode using ELF_C_READ_MMAP_PRIVATE (peep elf_begin for the lore on that). So like, the underlying memory image should not be directly modified by your application while its ELF descriptor is open. Mind the gap. 🫶

⚠️ okay so here's where it gets spicy: some libelf functions, elf_compress() and gelf_update_*() for example, may internally modify the underlying image, which means they need that image to be writable. If you hand them a read-only image (like, say, one memory mapped with PROT_READ only), you can get failures or crashes. Not the cute kind of crash. The bad kind. 😭

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🎀 PARAMETERS 🎀

• image — a pointer to a memory buffer holding the complete contents of an ELF file or archive. If it's NULL, this function fails and returns NULL. Rude but fair. 🙈
• size — how big, in bytes, the memory region pointed to by image is. It has to be at least as big as a full ELF header, and honestly it should cover the entire ELF object. Don't be stingy. ✨

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🌈 RETURN VALUE 🌈

On success, elf_memory() hands you a pointer to an Elf descriptor representing the archive or ELF file contained in image. Slay. 💅

On failure, it returns NULL and sets an error code you can retrieve with elf_errmsg(3). Go check it, bestie, it'll tell you what went wrong. 🔍

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👀 SEE ALSO 👀

• elf_begin(3)
• elf_errmsg(3)
• libelf(3)
• elf(5)

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⭐ ATTRIBUTES ⭐

ngl bestie, this section is just… empty in the original. Nothing listed. A little mysterious, a little main character energy, we move on. 💀

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🐛 REPORTING BUGS 🐛

Found a bug? Spill the tea, they want to hear it:

• report bugs to <elfutils-devel@sourceware.org>, or
• hit up https://sourceware.org/bugzilla/

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that's the whole page, bestie — go forth and descriptor-ify responsibly 🦋💖✨

Libelf · dated 2025-06-23 · ELF_MEMORY(3) — mwah, take care of her 🎀