Does anyone know where to find a summary table or cheatsheet for the Linux system call in Assembly? I am invoking Linux system calls through the int 0x80 instruction and I need a quick reference to determine which register contains which value from time to time.
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1You don't really need one, you just need to know the calling convention (e.g. ebx, ecx, edx, etc. for the 32-bit ABI) and the C argument order. [What are the calling conventions for UNIX & Linux system calls (and user-space functions) on i386 and x86-64](https://stackoverflow.com/q/2535989) (Plus the Notes section of the man page that comments on any differences between the C interface and the kernel, e.g. for brk/sbrk, or the way `getpriority(2)` encodes the return value to avoid negative values because those mean error.) – Peter Cordes Sep 16 '20 at 11:49
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Related: https://unix.stackexchange.com/questions/421750/where-do-you-find-the-syscall-table-for-linux – Ciro Santilli OurBigBook.com Nov 28 '20 at 13:08
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Here's an archive of a really good online reference with links to documentation and kernel source code.
Makyen
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Dean Harding
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The system calls can also be found in /usr/include/asm/unistd.h, which will point you to unistd32.h or unistd64.h
automaton
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And here's one more that's more easily navigable:
http://docs.cs.up.ac.za/programming/asm/derick_tut/syscalls.html
A scripting way to find out for your current machine:
ls /usr/share/man/man2 | sed -e s/.2.gz//g | xargs man -s 2 -k | sort | grep -v 'unimplemented system calls'
Credit - http://www.cs.fsu.edu/~langley/current-system-calls.html
