NetBSD/sys/kern/exec_elf_common.c

/*	$NetBSD: exec_elf_common.c,v 1.2 1996/09/27 03:38:27 cgd Exp $	*/

/*
 * Copyright (c) 1994 Christos Zoulas
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/exec.h>
#include <sys/exec_elf.h>
#include <sys/fcntl.h>
#include <sys/resourcevar.h>

#include <sys/mman.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_map.h>

#include <machine/cpu.h>
#include <machine/reg.h>
#include <machine/exec.h>

#ifdef COMPAT_LINUX
#include <compat/linux/linux_exec.h>
#endif

#ifdef COMPAT_SVR4
#include <compat/svr4/svr4_exec.h>
#endif

/*
 * exec_elf_setup_stack(): Set up the stack segment for an a.out
 * executable.
 *
 * Note that the ep_ssize parameter must be set to be the current stack
 * limit; this is adjusted in the body of execve() to yield the
 * appropriate stack segment usage once the argument length is
 * calculated.
 *
 * This function returns an int for uniformity with other (future) formats'
 * stack setup functions.  They might have errors to return.
 */

int
exec_elf_setup_stack(p, epp)
	struct proc *p;
	struct exec_package *epp;
{

	epp->ep_maxsaddr = USRSTACK - MAXSSIZ;
	epp->ep_minsaddr = USRSTACK;
	epp->ep_ssize = p->p_rlimit[RLIMIT_STACK].rlim_cur;

	/*
	 * set up commands for stack.  note that this takes *two*, one to
	 * map the part of the stack which we can access, and one to map
	 * the part which we can't.
	 *
	 * arguably, it could be made into one, but that would require the
	 * addition of another mapping proc, which is unnecessary
	 *
	 * note that in memory, things assumed to be: 0 ... ep_maxsaddr
	 * <stack> ep_minsaddr
	 */
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero,
	    ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr),
	    epp->ep_maxsaddr, NULLVP, 0, VM_PROT_NONE);
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize,
	    (epp->ep_minsaddr - epp->ep_ssize), NULLVP, 0,
	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	return 0;
}