/*	$NetBSD: linux_exec_aout.c,v 1.68 2015/10/18 16:59:19 maxv Exp $	*/

/*-
 * Copyright (c) 1995, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christos Zoulas, Frank van der Linden and Eric Haszlakiewicz.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION OR CONTRIBUTORS
 * 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.
 */

/*
 * based on exec_aout.c, sunos_exec.c and svr4_exec.c
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: linux_exec_aout.c,v 1.68 2015/10/18 16:59:19 maxv Exp $");

#ifdef _KERNEL_OPT
#include "opt_execfmt.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/exec.h>

#include <sys/mman.h>
#include <sys/syscallargs.h>

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

#include <compat/linux/common/linux_types.h>
#include <compat/linux/common/linux_signal.h>
#include <compat/linux/common/linux_util.h>
#include <compat/linux/common/linux_exec.h>
#include <compat/linux/common/linux_machdep.h>

#include <compat/linux/linux_syscallargs.h>
#include <compat/linux/linux_syscall.h>

int linux_aout_copyargs(struct lwp *, struct exec_package *,
    struct ps_strings *, char **, void *);

static int exec_linux_aout_prep_zmagic(struct lwp *,
    struct exec_package *);
static int exec_linux_aout_prep_nmagic(struct lwp *,
    struct exec_package *);
static int exec_linux_aout_prep_omagic(struct lwp *,
    struct exec_package *);
static int exec_linux_aout_prep_qmagic(struct lwp *,
    struct exec_package *);

int
linux_aout_copyargs(struct lwp *l, struct exec_package *pack,
    struct ps_strings *arginfo, char **stackp, void *argp)
{
	char **cpp = (char **)*stackp;
	char **stk = (char **)*stackp;
	char *dp, *sp;
	size_t len;
	void *nullp = NULL;
	int argc = arginfo->ps_nargvstr;
	int envc = arginfo->ps_nenvstr;
	int error;

	if ((error = copyout(&argc, cpp++, sizeof(argc))) != 0)
		return error;

	/* leave room for envp and argv */
	cpp += 2;
	if ((error = copyout(&cpp, &stk[1], sizeof (cpp))) != 0)
		return error;

	dp = (char *) (cpp + argc + envc + 2);
	sp = argp;

	/* XXX don't copy them out, remap them! */
	arginfo->ps_argvstr = cpp; /* remember location of argv for later */

	for (; --argc >= 0; sp += len, dp += len)
		if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0 ||
		    (error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0)
			return error;

	if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0)
		return error;

	if ((error = copyout(&cpp, &stk[2], sizeof (cpp))) != 0)
		return error;

	arginfo->ps_envstr = cpp; /* remember location of envp for later */

	for (; --envc >= 0; sp += len, dp += len)
		if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0 ||
		    (error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0)
			return error;

	if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0)
		return error;

	*stackp = (char *)cpp;
	return 0;
}

int
exec_linux_aout_makecmds(struct lwp *l, struct exec_package *epp)
{
	struct exec *linux_ep = epp->ep_hdr;
	int machtype, magic;
	int error = ENOEXEC;

	if (epp->ep_hdrvalid < sizeof(struct exec))
		return ENOEXEC;

	magic = LINUX_N_MAGIC(linux_ep);
	machtype = LINUX_N_MACHTYPE(linux_ep);

	if (machtype != LINUX_MID_MACHINE)
		return (ENOEXEC);

	switch (magic) {
	case QMAGIC:
		error = exec_linux_aout_prep_qmagic(l, epp);
		break;
	case ZMAGIC:
		error = exec_linux_aout_prep_zmagic(l, epp);
		break;
	case NMAGIC:
		error = exec_linux_aout_prep_nmagic(l, epp);
		break;
	case OMAGIC:
		error = exec_linux_aout_prep_omagic(l, epp);
		break;
	}
	return error;
}

/*
 * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400
 * is very likely not page aligned on most architectures, it is treated
 * as an NMAGIC here. XXX
 */

static int
exec_linux_aout_prep_zmagic(struct lwp *l, struct exec_package *epp)
{
	struct exec *execp = epp->ep_hdr;

	epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC);
	epp->ep_tsize = execp->a_text;
	epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC);
	epp->ep_dsize = execp->a_data + execp->a_bss;
	epp->ep_entry = execp->a_entry;

	/* set up command for text segment */
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC),
	    VM_PROT_READ|VM_PROT_EXECUTE);

	/* set up command for data segment */
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC),
	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	/* set up command for bss segment */
	if (execp->a_bss)
		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
		    epp->ep_daddr + execp->a_data, NULLVP, 0,
		    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	return (*epp->ep_esch->es_setup_stack)(l, epp);
}

/*
 * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package.
 * Not different from the normal stuff.
 */

static int
exec_linux_aout_prep_nmagic(struct lwp *l, struct exec_package *epp)
{
	struct exec *execp = epp->ep_hdr;
	long bsize, baddr;

	epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC);
	epp->ep_tsize = execp->a_text;
	epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC);
	epp->ep_dsize = execp->a_data + execp->a_bss;
	epp->ep_entry = execp->a_entry;

	/* set up command for text segment */
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC),
	    VM_PROT_READ|VM_PROT_EXECUTE);

	/* set up command for data segment */
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC),
	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	/* set up command for bss segment */
	baddr = roundup(epp->ep_daddr + execp->a_data, PAGE_SIZE);
	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
	if (bsize > 0)
		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	return (*epp->ep_esch->es_setup_stack)(l, epp);
}

/*
 * exec_aout_prep_omagic(): Prepare Linux OMAGIC package.
 * Business as usual.
 */

static int
exec_linux_aout_prep_omagic(struct lwp *l, struct exec_package *epp)
{
	struct exec *execp = epp->ep_hdr;
	long dsize, bsize, baddr;

	epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC);
	epp->ep_tsize = execp->a_text;
	epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC);
	epp->ep_dsize = execp->a_data + execp->a_bss;
	epp->ep_entry = execp->a_entry;

	/* set up command for text and data segments */
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn,
	    execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp,
	    LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	/* set up command for bss segment */
	baddr = roundup(epp->ep_daddr + execp->a_data, PAGE_SIZE);
	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
	if (bsize > 0)
		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	/*
	 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize);
	 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are
	 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize'
	 * respectively to page boundaries.
	 * Compensate `ep_dsize' for the amount of data covered by the last
	 * text page.
	 */
	dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text,
							PAGE_SIZE);
	epp->ep_dsize = (dsize > 0) ? dsize : 0;
	return (*epp->ep_esch->es_setup_stack)(l, epp);
}

static int
exec_linux_aout_prep_qmagic(struct lwp *l, struct exec_package *epp)
{
	struct exec *execp = epp->ep_hdr;
	int error;

	epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC);
	epp->ep_tsize = execp->a_text;
	epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC);
	epp->ep_dsize = execp->a_data + execp->a_bss;
	epp->ep_entry = execp->a_entry;

	error = vn_marktext(epp->ep_vp);
	if (error)
		return (error);

	/* set up command for text segment */
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text,
	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC),
	    VM_PROT_READ|VM_PROT_EXECUTE);

	/* set up command for data segment */
	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data,
	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC),
	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	/* set up command for bss segment */
	if (execp->a_bss)
		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
		    epp->ep_daddr + execp->a_data, NULLVP, 0,
		    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);

	return (*epp->ep_esch->es_setup_stack)(l, epp);
}