/**************************************************************************/

/*  mmglue: midipix architecture- and target-specific bits for musl libc  */

/*  Copyright (C) 2013--2023  SysDeer Technologies, LLC                   */

/*  Released under the Standard MIT License; see COPYING.MMGLUE.          */

/**************************************************************************/

#define  _GNU_SOURCE

#include <syscall.h>

#include <sched.h>

/* take advantage of i686 vararg abi */

#define  __clone ____clone

#include "pthread_impl.h"

#undef   __clone

struct pt_regs {

	unsigned long	ebx;

	unsigned long	ecx;

	unsigned long	edx;

	unsigned long	esi;

	unsigned long	edi;

	unsigned long	ebp;

	unsigned long	eax;

	unsigned long	xds;

	unsigned long	xes;

	unsigned long	xfs;

	unsigned long	xgs;

	unsigned long	orig_eax;

	unsigned long	eip;

	unsigned long	xcs;

	unsigned long	eflags;

	unsigned long	esp;

	unsigned long	xss;

	unsigned long	sbase;

	unsigned long	slimit;

	unsigned long	sbottom;

};

typedef long __sys_clone(

	unsigned long	flags,

	void *		child_stack,

	void *		ptid,

	void *		ctid,

	struct pt_regs *regs);

extern unsigned long ** __syscall_vtbl;

int __clone(

	__entry_point *	fn,

	void *		child_stack,

	int		flags,

	void *		arg,

	int *		ptid,

	void *		pthread_self_addr,

	int *		ctid)

{

	uintptr_t       sbase;

	uintptr_t       slimit;

	uintptr_t       sbottom;

	void *          stack;

	struct pt_regs	regs;

	__sys_clone *	pfn_clone;

	pthread_t	pthread;

	regs.eip = (unsigned long)fn;

	regs.ecx = (unsigned long)arg;

	regs.edx = (unsigned long)pthread_self_addr;

	pfn_clone = (__sys_clone *)(__syscall_vtbl[SYS_clone]);

	sbase  = (uintptr_t)child_stack;

	sbase &= ~(uintptr_t)(0xf);

	stack  = (void *)sbase;

	if (flags == (CLONE_VM|CLONE_VFORK|SIGCHLD)) {

		regs.sbase   = 0;

		regs.slimit  = 0;

		regs.sbottom = 0;

		return (int)pfn_clone(

			flags,

			stack,

			0,0,®s;;

	}

	pthread = (pthread_t)pthread_self_addr;

	sbase   = (uintptr_t)pthread->stack;

	slimit  = sbase - pthread->stack_size;

	sbottom = slimit - pthread->guard_size;

	sbase  &= ~(uintptr_t)(0xf);

	slimit += 0xf;

	slimit |= 0xf;

	slimit ^= 0xf;

	regs.sbase   = sbase;

	regs.slimit  = slimit;

	regs.sbottom = sbottom;

	return (int)pfn_clone(

		flags,

		stack,

		ptid,

		ctid,

		®s;;

}