LXR linux-old/fs/binfmt

   1/*
   2 *  linux/fs/binfmt_em86.c
   3 *
   4 *  Based on linux/fs/binfmt_script.c
   5 *  Copyright (C) 1996  Martin von Löwis
   6 *  original #!-checking implemented by tytso.
   7 *
   8 *  em86 changes Copyright (C) 1997  Jim Paradis
   9 */
  10
  11#include <linux/module.h>
  12#include <linux/string.h>
  13#include <linux/stat.h>
  14#include <linux/malloc.h>
  15#include <linux/binfmts.h>
  16#include <linux/elf.h>
  17#include <linux/init.h>
  18
  19
  20#define EM86_INTERP     "/usr/bin/em86"
  21#define EM86_I_NAME     "em86"
  22
  23static int load_em86(struct linux_binprm *bprm,struct pt_regs *regs)
  24{
  25        char *interp, *i_name, *i_arg;
  26        struct dentry * dentry;
  27        int retval;
  28        struct elfhdr   elf_ex;
  29
  30        /* Make sure this is a Linux/Intel ELF executable... */
  31        elf_ex = *((struct elfhdr *)bprm->buf);
  32
  33        if (elf_ex.e_ident[0] != 0x7f ||
  34            strncmp(&elf_ex.e_ident[1], "ELF",3) != 0) {
  35                return  -ENOEXEC;
  36        }
  37
  38
  39        /* First of all, some simple consistency checks */
  40        if ((elf_ex.e_type != ET_EXEC &&
  41            elf_ex.e_type != ET_DYN) ||
  42           (!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) ||
  43           (!bprm->dentry->d_inode->i_op || !bprm->dentry->d_inode->i_op->default_file_ops ||
  44            !bprm->dentry->d_inode->i_op->default_file_ops->mmap)){
  45                return -ENOEXEC;
  46        }
  47
  48        bprm->sh_bang++;        /* Well, the bang-shell is implicit... */
  49        dput(bprm->dentry);
  50        bprm->dentry = NULL;
  51
  52        /* Unlike in the script case, we don't have to do any hairy
  53         * parsing to find our interpreter... it's hardcoded!
  54         */
  55        interp = EM86_INTERP;
  56        i_name = EM86_I_NAME;
  57        i_arg = NULL;           /* We reserve the right to add an arg later */
  58
  59        /*
  60         * Splice in (1) the interpreter's name for argv[0]
  61         *           (2) (optional) argument to interpreter
  62         *           (3) filename of emulated file (replace argv[0])
  63         *
  64         * This is done in reverse order, because of how the
  65         * user environment and arguments are stored.
  66         */
  67        remove_arg_zero(bprm);
  68        bprm->p = copy_strings(1, &bprm->filename, bprm->page, bprm->p, 2);
  69        bprm->argc++;
  70        if (i_arg) {
  71                bprm->p = copy_strings(1, &i_arg, bprm->page, bprm->p, 2);
  72                bprm->argc++;
  73        }
  74        bprm->p = copy_strings(1, &i_name, bprm->page, bprm->p, 2);
  75        bprm->argc++;
  76        if ((long)bprm->p < 0)
  77                return (long)bprm->p;
  78        /*
  79         * OK, now restart the process with the interpreter's inode.
  80         * Note that we use open_namei() as the name is now in kernel
  81         * space, and we don't need to copy it.
  82         */
  83        dentry = open_namei(interp, 0, 0);
  84        if (IS_ERR(dentry))
  85                return PTR_ERR(dentry);
  86
  87        bprm->dentry = dentry;
  88
  89        retval = prepare_binprm(bprm);
  90        if (retval < 0)
  91                return retval;
  92
  93        return search_binary_handler(bprm, regs);
  94}
  95
  96struct linux_binfmt em86_format = {
  97        module:         THIS_MODULE,
  98        load_binary:    load_em86,
  99};
 100
 101int __init init_em86_binfmt(void)
 102{
 103        return register_binfmt(&em86_format);
 104}
 105
 106#ifdef MODULE
 107int init_module(void)
 108{
 109        return init_em86_binfmt();
 110}
 111
 112void cleanup_module( void) {
 113        unregister_binfmt(&em86_format);
 114}
 115#endif
 116