/*      $NetBSD: m68k4k_exec.c,v 1.25 2019/11/20 19:37:53 pgoyette Exp $        */

/*
 * Copyright (c) 1993, 1994 Christopher G. Demetriou
 * 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 by Christopher G. Demetriou.
 * 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.
 */

/*
 * Exec glue to provide compatibility with older NetBSD m68k4k exectuables.
 *
 * Taken directly from kern/exec_aout.c and frobbed to map text and
 * data as m68k4k executables expect.
 *
 * This module only works on machines with PAGE_SIZE == 4096.  It's not clear
 * that making it work on other machines is worth the trouble.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: m68k4k_exec.c,v 1.25 2019/11/20 19:37:53 pgoyette Exp $");

#if !defined(__m68k__)
#error YOU GOTTA BE KIDDING!
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/vnode.h>
#include <sys/exec.h>
#include <sys/exec_aout.h>
#include <sys/resourcevar.h>

#include <compat/m68k4k/m68k4k_exec.h>

MODULE(MODULE_CLASS_EXEC, exec_m68k4k, NULL);

static struct execsw exec_m68k4k_execsw = {
        .es_hdrsz = sizeof(struct exec),
        .es_makecmds = exec_m68k4k_makecmds,
        .u = {
                .elf_probe_func = NULL,
        },
        .es_emul = &emul_netbsd,
        .es_prio = EXECSW_PRIO_ANY,
        .es_arglen = 0,
        .es_copyargs = copyargs,
        .es_setregs = NULL,
        .es_coredump = coredump_netbsd,
        .es_setup_stack = exec_setup_stack,
};

static int
exec_m68k4k_modcmd(modcmd_t cmd, void *arg)
{

        switch (cmd) {
        case MODULE_CMD_INIT:
                return exec_add(&exec_m68k4k_execsw, 1);

        case MODULE_CMD_FINI:
                return exec_remove(&exec_m68k4k_execsw, 1);

        default:
                return ENOTTY;
        }
}

int     exec_m68k4k_prep_zmagic(struct lwp *, struct exec_package *);
int     exec_m68k4k_prep_nmagic(struct lwp *, struct exec_package *);
int     exec_m68k4k_prep_omagic(struct lwp *, struct exec_package *);

/*
 * exec_m68k4k_makecmds(): Check if it's an a.out-format executable
 * with an m68k4k magic number.
 *
 * Given a proc pointer and an exec package pointer, see if the referent
 * of the epp is in a.out format.  Just check 'standard' magic numbers for
 * this architecture.
 *
 * This function, in the former case, or the hook, in the latter, is
 * responsible for creating a set of vmcmds which can be used to build
 * the process's vm space and inserting them into the exec package.
 */

int
exec_m68k4k_makecmds(struct lwp *l, struct exec_package *epp)
{
        u_long midmag, magic;
        u_short mid;
        int error;
        struct exec *execp = epp->ep_hdr;

        /* See note above... */
        if (M68K4K_LDPGSZ != PAGE_SIZE)
                return ENOEXEC;

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

        midmag = ntohl(execp->a_midmag);
        mid = (midmag >> 16) & 0x3ff;
        magic = midmag & 0xffff;

        midmag = mid << 16 | magic;

        switch (midmag) {
        case (MID_M68K4K << 16) | ZMAGIC:
                error = exec_m68k4k_prep_zmagic(l, epp);
                break;
        case (MID_M68K4K << 16) | NMAGIC:
                error = exec_m68k4k_prep_nmagic(l, epp);
                break;
        case (MID_M68K4K << 16) | OMAGIC:
                error = exec_m68k4k_prep_omagic(l, epp);
                break;
        default:
                error = ENOEXEC;
        }

        if (error)
                kill_vmcmds(&epp->ep_vmcmds);

        return error;
}

/*
 * exec_m68k4k_prep_zmagic(): Prepare an m68k4k ZMAGIC binary's exec package
 *
 * First, set of the various offsets/lengths in the exec package.
 *
 * Then, mark the text image busy (so it can be demand paged) or error
 * out if this is not possible.  Finally, set up vmcmds for the
 * text, data, bss, and stack segments.
 */

int
exec_m68k4k_prep_zmagic(struct lwp *l, struct exec_package *epp)
{
        struct exec *execp = epp->ep_hdr;
        int error;

        epp->ep_taddr = M68K4K_USRTEXT;
        epp->ep_tsize = execp->a_text;
        epp->ep_daddr = epp->ep_taddr + execp->a_text;
        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, 0, 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, execp->a_text,
            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_m68k4k_prep_nmagic(): Prepare a m68k4k NMAGIC binary's exec package
 */

int
exec_m68k4k_prep_nmagic(struct lwp *l, struct exec_package *epp)
{
        struct exec *execp = epp->ep_hdr;
        long bsize, baddr;

        epp->ep_taddr = M68K4K_USRTEXT;
        epp->ep_tsize = execp->a_text;
        epp->ep_daddr = roundup(epp->ep_taddr + execp->a_text,
            M68K4K_LDPGSZ);
        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, sizeof(struct exec),
            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, execp->a_text + sizeof(struct exec),
            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_m68k4k_prep_omagic(): Prepare a m68k4k OMAGIC binary's exec package
 */

int
exec_m68k4k_prep_omagic(struct lwp *l, struct exec_package *epp)
{
        struct exec *execp = epp->ep_hdr;
        long dsize, bsize, baddr;

        epp->ep_taddr = M68K4K_USRTEXT;
        epp->ep_tsize = execp->a_text;
        epp->ep_daddr = epp->ep_taddr + execp->a_text;
        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,
            sizeof(struct exec), 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);
}