1. 根目录:
2. arch
3. um
4. sys-i386
5. syscalls.c

/* 
 * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
 * Licensed under the GPL
 */

#include "linux/sched.h"
#include "linux/shm.h"
#include "linux/ipc.h"
#include "linux/syscalls.h"
#include "asm/mman.h"
#include "asm/uaccess.h"
#include "asm/unistd.h"

/*
 * The prototype on i386 is:
 *
 *     int clone(int flags, void * child_stack, int * parent_tidptr, struct user_desc * newtls, int * child_tidptr)
 *
 * and the "newtls" arg. on i386 is read by copy_thread directly from the
 * register saved on the stack.
 */
long sys_clone(unsigned long clone_flags, unsigned long newsp,
	       int __user *parent_tid, void *newtls, int __user *child_tid)
{
	long ret;

	if (!newsp)
		newsp = UPT_SP(&current->thread.regs.regs);

	current->thread.forking = 1;
	ret = do_fork(clone_flags, newsp, &current->thread.regs, 0, parent_tid,
		      child_tid);
	current->thread.forking = 0;
	return ret;
}

long sys_sigaction(int sig, const struct old_sigaction __user *act,
			 struct old_sigaction __user *oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

	if (act) {
		old_sigset_t mask;
		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
			return -EFAULT;
		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
		__get_user(mask, &act->sa_mask);
		siginitset(&new_ka.sa.sa_mask, mask);
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

	if (!ret && oact) {
		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
			return -EFAULT;
		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
	}

	return ret;
}