ucontext implementation featuring glibc-compatible ABI

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A. Wilcox 6046eb47e4 Reorder registers in other x86_64 assembler files This fixes the previous commit which changed the register order in swapcontext only, which caused setcontext to subtly corrupt the stack.		2018-07-19 17:18:19 -05:00
arch	Reorder registers in other x86_64 assembler files	2018-07-19 17:18:19 -05:00
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LICENSE	don't bother with glibc stuff afterall, kernel defines ABI to use	2018-01-29 21:50:49 +00:00
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README.md	README: we support s390x now	2018-02-15 05:55:26 +00:00
test_libucontext.c	test_libucontext: explain the stack poisoning part	2018-01-31 23:23:45 +00:00

README.md

`libucontext`

libucontext is a library which provides the ucontext.h C API. Unlike other implementations, it faithfully follows the kernel process ABI when doing context swaps.

Notably, when combined with gcompat, it provides a fully compatible implementation of the ucontext functions that are ABI compatible with glibc.

supported architectures

Adding support for new architectures is easy, but you need to know assembly language to do it.

Right now these archs are supported and should work on bare metal:

x86
x86_64
armv6+ (arm)
aarch64
s390x

These archs require kernel assistance and use a syscall (the only assembly is the trampoline):

ppc
ppc64 (ELFv2 ABI spec only, ELFv1 not supported)

building

libucontext uses a simple makefile build system. You should define ARCH= at build time, otherwise the build system will attempt to guess using uname -m.

$ make ARCH=x86_64
$ make ARCH=x86_64 check
$ make ARCH=x86_64 DESTDIR=out install

support

libucontext is offered as part of the gcompat project. Accordingly, please address all questions and bug reports to gcompat@lists.adelielinux.org.