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/*

 *  linux/fs/binfmt_em86.c

 *

 *  Based on linux/fs/binfmt_script.c

 *  Copyright (C) 1996  Martin von Löwis

 *  original #!-checking implemented by tytso.

 *

 *  em86 changes Copyright (C) 1997  Jim Paradis

 */

#include <linux/module.h>

#include <linux/string.h>

#include <linux/stat.h>

#include <linux/malloc.h>

#include <linux/binfmts.h>

#include <linux/elf.h>

#define EM86_INTERP     "/usr/bin/em86"

#define EM86_I_NAME     "em86"

static int do_load_em86(struct linux_binprm *bprm,struct pt_regs *regs)

{

        char *cp, *interp, *i_name, *i_arg;

        int retval;

        struct elfhdr   elf_ex;

        uid_t           x86_uid;

        gid_t           x86_gid;

        /* Make sure this is a Linux/Intel ELF executable... */

        elf_ex = *((struct elfhdr *)bprm->buf);

        if (elf_ex.e_ident[0] != 0x7f ||

            strncmp(&elf_ex.e_ident[1], "ELF",3) != 0) {

                return  -ENOEXEC;

        }

        /* First of all, some simple consistency checks */

        if ((elf_ex.e_type != ET_EXEC &&

            elf_ex.e_type != ET_DYN) ||

           (!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) ||

           (!bprm->inode->i_op || !bprm->inode->i_op->default_file_ops ||

            !bprm->inode->i_op->default_file_ops->mmap)){

                return -ENOEXEC;

        }

        bprm->sh_bang++;        /* Well, the bang-shell is implicit... */

        iput(bprm->inode);

        bprm->dont_iput = 1;

        /* Unlike in the script case, we don't have to do any hairy

         * parsing to find our interpreter... it's hardcoded!

         */

        interp = EM86_INTERP;

        i_name = EM86_I_NAME;

        i_arg = NULL;           /* We reserve the right to add an arg later */

        /*

         * Splice in (1) the interpreter's name for argv[0]

         *           (2) (optional) argument to interpreter

         *           (3) filename of emulated file (replace argv[0])

         *

         * This is done in reverse order, because of how the

         * user environment and arguments are stored.

         */

        remove_arg_zero(bprm);

        bprm->p = copy_strings(1, &bprm->filename, bprm->page, bprm->p, 2);

        bprm->argc++;

        if (i_arg) {

                bprm->p = copy_strings(1, &i_arg, bprm->page, bprm->p, 2);

                bprm->argc++;

        }

        bprm->p = copy_strings(1, &i_name, bprm->page, bprm->p, 2);

        bprm->argc++;

        if (!bprm->p)

                return -E2BIG;

        /*

         * OK, now restart the process with the interpreter's inode.

         * Note that we use open_namei() as the name is now in kernel

         * space, and we don't need to copy it.

         */

        retval = open_namei(interp, 0, 0, &bprm->inode, NULL);

        if (retval)

                return retval;

        bprm->dont_iput=0;

        /* Remember the uid/gid that was set by this executable */

        x86_uid = bprm->e_uid;

        x86_gid = bprm->e_gid;

        retval=prepare_binprm(bprm);

        if(retval<0)

                return retval;

        /* ...so that we may propagate them to em86 */

        bprm->e_uid = x86_uid;

        bprm->e_gid = x86_gid;

        current->personality = PER_LINUX_EM86;

        return search_binary_handler(bprm,regs);

}

static int load_em86(struct linux_binprm *bprm,struct pt_regs *regs)

{

        int retval;

        MOD_INC_USE_COUNT;

        retval = do_load_em86(bprm,regs);

        MOD_DEC_USE_COUNT;

        return retval;

}

struct linux_binfmt em86_format = {

#ifndef MODULE

        NULL, 0, load_em86, NULL, NULL

#else

        NULL, &mod_use_count_, load_em86, NULL, NULL

#endif

};

int init_em86_binfmt(void) {

        return register_binfmt(&em86_format);

}

#ifdef MODULE

int init_module(void)

{

        return init_em86_binfmt();

}

void cleanup_module( void) {

        unregister_binfmt(&em86_format);

}

#endif