9 ms·

Any good resources to learn about that?

by 22SAS 3y ago

duped 3y ago
The book "Linkers an Loaders" by Levine is the Bible on the subject
- ndesaulniers 3y ago
  Yes; but there's also descriptions of legacy container formats no one cares about any more. I still recommend it and have my own copy, I just recall skipping over quite a bit of material.
- Findecanor 3y ago
  It used to be available online for free at <https://www.iecc.com/linker/ https://www.iecc.com/linker/>, but isn't any more. You could get it from archive.org though, and I think I've seen mirrors in other formats on Hacker News in previous discussions about the book.
bluetomcat 3y ago
"man 5 elf" should be the ultimate source of truth :-)
- convolvatron 3y ago
  the elf specification is: https://refspecs.linuxfoundation.org/elf/elf.pdf https://refspecs.linuxfoundation.org/elf/elf.pdf
yrro 3y ago
I've found that searching for stories with ELF in the title then trawling through the comments for the links is really informative.
- eddtests 3y ago
  I just hope they catch this Sauron before it’s too late…
mimimi31 3y ago
There's a great summary from LWN[1] with lots of references and links to other articles for further reading. [1] https://lwn.net/Articles/631631 https://lwn.net/Articles/631631
emidln 3y ago
The source code to the kernel's elf "binfmt"[0] is very readable. The elf binfmt is registered (along with a few others like `binfmt_misc`) and you get dispatched there via `exec_binprm`[1] which is invoked by the `execve` syscall[2]. When loading a shared library, you also dispatch to a binfmt via the `uselib`[3] syscall. [0] https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be514f4abbfc071004cbe7/fs/binfmt_elf.c#L823 https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be5... [1] https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be514f4abbfc071004cbe7/fs/exec.c#L1764 https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be5... [2] https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be514f4abbfc071004cbe7/fs/exec.c#L1812 https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be5... [3] https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be514f4abbfc071004cbe7/fs/exec.c#L158 https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be5...
proto_lambda 3y ago
If you're interested in or already comfortable with Rust, Amos (fasterthanlime) has a nice long-form series that goes into this, basically building a custom ELF loader in the end. The writing style isn't everyone's cup of tea, but maybe you like it: https://fasterthanli.me/series/making-our-own-executable-packer/ https://fasterthanli.me/series/making-our-own-executable-pac...
dharmab 3y ago
CPU Land is an accessible introduction. This chapter covers ELF https://cpu.land/becoming-an-elf-lord https://cpu.land/becoming-an-elf-lord

Any good resources to learn about that?

by 22SAS 3y ago

Any good resources to learn about that?

duped 3y ago

The book "Linkers an Loaders" by Levine is the Bible on the subject

ndesaulniers 3y ago
Yes; but there's also descriptions of legacy container formats no one cares about any more. I still recommend it and have my own copy, I just recall skipping over quite a bit of material.
Findecanor 3y ago
It used to be available online for free at <https://www.iecc.com/linker/ https://www.iecc.com/linker/>, but isn't any more. You could get it from archive.org though, and I think I've seen mirrors in other formats on Hacker News in previous discussions about the book.

bluetomcat 3y ago

"man 5 elf" should be the ultimate source of truth :-)

convolvatron 3y ago
the elf specification is: https://refspecs.linuxfoundation.org/elf/elf.pdf https://refspecs.linuxfoundation.org/elf/elf.pdf

yrro 3y ago

I've found that searching for stories with ELF in the title then trawling through the comments for the links is really informative.

eddtests 3y ago
I just hope they catch this Sauron before it’s too late…

mimimi31 3y ago

There's a great summary from LWN[1] with lots of references and links to other articles for further reading. [1] https://lwn.net/Articles/631631 https://lwn.net/Articles/631631

emidln 3y ago

The source code to the kernel's elf "binfmt"[0] is very readable. The elf binfmt is registered (along with a few others like `binfmt_misc`) and you get dispatched there via `exec_binprm`[1] which is invoked by the `execve` syscall[2]. When loading a shared library, you also dispatch to a binfmt via the `uselib`[3] syscall. [0] https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be514f4abbfc071004cbe7/fs/binfmt_elf.c#L823 https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be5... [1] https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be514f4abbfc071004cbe7/fs/exec.c#L1764 https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be5... [2] https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be514f4abbfc071004cbe7/fs/exec.c#L1812 https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be5... [3] https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be514f4abbfc071004cbe7/fs/exec.c#L158 https://github.com/torvalds/linux/blob/9fdfb15a3dbf818e06be5...

proto_lambda 3y ago

If you're interested in or already comfortable with Rust, Amos (fasterthanlime) has a nice long-form series that goes into this, basically building a custom ELF loader in the end. The writing style isn't everyone's cup of tea, but maybe you like it: https://fasterthanli.me/series/making-our-own-executable-packer/ https://fasterthanli.me/series/making-our-own-executable-pac...

dharmab 3y ago

CPU Land is an accessible introduction. This chapter covers ELF https://cpu.land/becoming-an-elf-lord https://cpu.land/becoming-an-elf-lord