Support for multiple processes

[LHLaurini]

linux/tools/lkl/lib/posix-host.c

Lines 27 to 28 in 1844b34

	/* TODO(pscollins): We don't support fork() for now, but maybe one day
	* we will? */

linux/arch/lkl/include/asm/syscalls.h

Lines 11 to 12 in 1844b34

	#define sys_clone sys_ni_syscall
	#define sys_vfork sys_ni_syscall

Right now, the fork, vfork and clone syscalls are not implemented. Is it possible to add support for multiple processes?

[LHLaurini]

Answering my own question, I believe that could be possible. We'd need to actually fork the process, which means we'd lose direct access to lkl. So we'd have to use some form of IPC, possibly shared memory and semaphores.

[tavip]

Any use-case you have in mind? Fully implementing fork/clone would require MMU support, which we don't currently have.

[LHLaurini]

Many programs use fork, like sh, make, some compilers, etc... So not supporting it could limit possible applications.

More specifically, I had intended to use lkl for compiling stuff that needs chroot and mount (like Linux from Scratch) without requiring root or even being able to compile it on Windows.

[tavip]

This is not a use-case that we plan to suport with LKL. UML or VMs are better suited for these kind of uses-cases.

[LHLaurini]

Indeed, UML fits my use case better.