/*	$NetBSD: linux_exec.c,v 1.2 1995/03/05 23:23:37 fvdl Exp $	*/

/*
 * Copyright (c) 1995 Frank van der Linden
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed for the NetBSD Project
 *      by Frank van der Linden
 * 4. 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.
 *
 * based on kern/exec_aout.c and compat/sunos/sunos_exec.c
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/resourcevar.h>
#include <sys/wait.h>

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

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

#include <compat/linux/linux_types.h>
#include <compat/linux/linux_syscallargs.h>
#include <compat/linux/linux_util.h>
#include <compat/linux/linux_exec.h>

int
exec_linux_aout_makecmds(p, epp)
	struct proc *p;
	struct exec_package *epp;
{
	struct exec *linux_ep = epp->ep_hdr;
	int machtype, magic;
	int error = 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(p, epp);
		break;
	case ZMAGIC:
		error = exec_linux_aout_prep_zmagic(p, epp);
		break;
	case NMAGIC:
		error = exec_linux_aout_prep_nmagic(p, epp);
		break;
	case OMAGIC:
		error = exec_linux_aout_prep_omagic(p, epp);
		break;
	}
	if (error == 0)
		epp->ep_emul = EMUL_LINUX;
	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
 */

int
exec_linux_aout_prep_zmagic(p, epp)
	struct proc *p;
	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 */
	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 exec_aout_setup_stack(p, epp);
}

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

int
exec_linux_aout_prep_nmagic(p, epp)
	struct proc *p;
	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, NBPG);
	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 exec_aout_setup_stack(p, epp);
}

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

int
exec_linux_aout_prep_omagic(p, epp)
	struct proc *p;
	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, NBPG);
	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, NBPG);
	epp->ep_dsize = (dsize > 0) ? dsize : 0;
	return exec_aout_setup_stack(p, epp);
}

int
exec_linux_aout_prep_qmagic(p, epp)
	struct proc *p;
	struct exec_package *epp;
{
	struct exec *execp = epp->ep_hdr;

	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;

	/*
	 * check if vnode is in open for writing, because we want to
	 * demand-page out of it.  if it is, don't do it, for various
	 * reasons
	 */
	if ((execp->a_text != 0 || execp->a_data != 0) &&
	    epp->ep_vp->v_writecount != 0) {
#ifdef DIAGNOSTIC
		if (epp->ep_vp->v_flag & VTEXT)
			panic("exec: a VTEXT vnode has writecount != 0\n");
#endif
		return ETXTBSY;
	}
	epp->ep_vp->v_flag |= VTEXT;

	/* 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 */
	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 exec_aout_setup_stack(p, epp);
}

/*
 * The Linux system call to load shared libraries. The current shared
 * libraries are just (QMAGIC) a.out files that are mapped onto a fixed
 * address * in the process' address space. The address is given in
 * a_entry. Read in the header, set up some VM commands and run them.
 *
 * Yes, both text and data are mapped at once, so we're left with
 * writeable text for the shared libs. The Linux crt0 seemed to break
 * sometimes when data was mapped seperately. It munmapped a uselib()
 * of ld.so by hand, which failed with shared text and data for ld.so
 * Yuck.
 *
 * Because of the problem with ZMAGIC executables (text starts
 * at 0x400 in the file, but needs t be mapped at 0), ZMAGIC
 * shared libs are not handled very efficiently :-(
 */

int
linux_uselib(p, uap, retval)
	struct proc *p;
	struct linux_uselib_args /* {
		syscallarg(char *) path;
	} */ *uap;
	register_t *retval;
{
	caddr_t sg;
	long bsize, dsize, tsize, taddr, baddr, daddr;
	struct nameidata ni;
	struct vnode *vp;
	struct exec hdr;
	struct exec_vmcmd_set vcset;
	int rem, i, magic, error;

	sg = stackgap_init();
	CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));

	NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);

	if ((error = namei(&ni)))
		return error;

	vp = ni.ni_vp;

	if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE,
			     0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred,
			     &rem, p))) {
		vrele(vp);
		return error;
	}

	if (rem != 0) {
		vrele(vp);
		return ENOEXEC;
	}

	magic = LINUX_N_MAGIC(&hdr);
	taddr = hdr.a_entry & (~(NBPG - 1));
	tsize = hdr.a_text;
	daddr = taddr + tsize;
	dsize = hdr.a_data + hdr.a_bss;

	if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) {
		vrele(vp);
                return ETXTBSY;
        }
	vp->v_flag |= VTEXT;

	vcset.evs_cnt = 0;
	vcset.evs_used = 0;

	NEW_VMCMD(&vcset,
		  magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn,
		  hdr.a_text + hdr.a_data, taddr,
		  vp, LINUX_N_TXTOFF(hdr, magic),
		  VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE);

	baddr = roundup(daddr + hdr.a_data, NBPG);
	bsize = daddr + dsize - baddr;
        if (bsize > 0) {
                NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr,
                    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
	}

	for (i = 0; i < vcset.evs_used && !error; i++) {
		struct exec_vmcmd *vcp;

		vcp = &vcset.evs_cmds[i];
		error = (*vcp->ev_proc)(p, vcp);
	}

	kill_vmcmds(&vcset);

	vrele(vp);

	return error;
}

/*
 * Execve(2). Just check the alternate emulation path, and pass it on
 * to the NetBSD execve().
 */
int
linux_execve(p, uap, retval)
	struct proc *p;
	struct linux_execve_args /* {
		syscallarg(char *) path;
		syscallarg(char **) argv;
		syscallarg(char **) envp;
	} */ *uap;
	register_t *retval;
{
	caddr_t sg;

	sg = stackgap_init();
	CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));

	return execve(p, uap, retval);
}