Don't support elf file?

[fbs2016]

I try to parse an elf file but it return undefined and can't find elf file from "Supported file types".

[sindresorhus]

What is an elf file?

[fbs2016]

Like .out/.o file:
sh-5.0$ file hello.out
hello.out: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), with debug_info, not stripped

[SpraxDev]

According to Wikipedia

In computing, the Executable and Linkable Format (ELF, formerly named Extensible Linking Format), is a common standard file format for executable files, object code, shared libraries, and core dumps.

There's sadly no issue template where I can see what info is needed for a new type to be added but I'll try my best:

Magic numbers (hex): 7f 45 4c 46
Mime type: application/x-elf (Apperantly application/x-coredump, application/x-executable, application/x-object and application/x-sharedlib are valid too but less common as they require parsing the file header)
File extensions (hard to say as it is used with a lot of variety): .so, .o, .elf, .bin

You can find some additional information on https://manpages.debian.org/buster/manpages/elf.5.en.html

[somebody1234]

  if (check([0x7F, 0x45, 0x4c, 0x46])) {
    return ['', 'application/x-elf'];
  }

should work. not sure what to do about file extensions; generally when you're checking the filetype of a binary it probably won't have an extension

[Marinell0]

Was this fixed with #514 ?

[Borewit]

I think ELF has been implemented:

file-type/core.js

Lines 789 to 794 in 4110073

	if (this.check([0x7F, 0x45, 0x4C, 0x46])) {
	return {
	ext: 'elf',
	mime: 'application/x-elf',
	};
	}

[regamboa]

Hi, folks:

I had posted a comment to Sindre via Twitter, who suggested that I repeat it here. The ELF file format is the standard executable format for Linux/Unix, the same way that the Portable Executable format is for Windows. Typically in Unix land, one doesn't use file extensions for executables. Instead, you need to check headers and magic numbers as you have been doing. You managed to spot the magic number, but what you might not realize is that it spells out Unicode character 0x7f followed by 'ELF'.

There's a C library called BFD (binary file descriptors), which is part of the binutils project (https://www.gnu.org/software/binutils/) that makes file checking quite a bit easier.Binutils is also the home for the GNU assembler (gas) and is considered a core part of all Linux distributions. It's also available for Windows via Cygwin and Mac, as well as other OS platforms.

If you want more details on the ELF file format specifically, note that the specification doesn't exist on its own. It's part of the Unix ABI (Application Binary Interface) specification at http://www.sco.com/developers/devspecs/gabi41.pdf. Chapters 4 and 5 provide relevant details on the ELF format.

I've been programming on Linux for...eeek, a couple of decades now, so if you need more information, please feel free to contact me at robygamboa@gmail.com.