LXR linux-bk/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/slab.h>
  15#include <linux/smp_lock.h>
  16#include <linux/binfmts.h>
  17#include <linux/elf.h>
  18#include <linux/init.h>
  19#include <linux/fs.h>
  20#include <linux/file.h>
  21#include <linux/errno.h>
  22
  23
  24#define EM86_INTERP     "/usr/bin/em86"
  25#define EM86_I_NAME     "em86"
  26
  27static int load_em86(struct linux_binprm *bprm,struct pt_regs *regs)
  28{
  29        char *interp, *i_name, *i_arg;
  30        struct file * file;
  31        int retval;
  32        struct elfhdr   elf_ex;
  33
  34        /* Make sure this is a Linux/Intel ELF executable... */
  35        elf_ex = *((struct elfhdr *)bprm->buf);
  36
  37        if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
  38                return  -ENOEXEC;
  39
  40        /* First of all, some simple consistency checks */
  41        if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
  42                (!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) ||
  43                (!bprm->file->f_op || !bprm->file->f_op->mmap)) {
  44                        return -ENOEXEC;
  45        }
  46
  47        bprm->sh_bang++;        /* Well, the bang-shell is implicit... */
  48        allow_write_access(bprm->file);
  49        fput(bprm->file);
  50        bprm->file = 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        retval = copy_strings_kernel(1, &bprm->filename, bprm);
  69        if (retval < 0) return retval; 
  70        bprm->argc++;
  71        if (i_arg) {
  72                retval = copy_strings_kernel(1, &i_arg, bprm);
  73                if (retval < 0) return retval; 
  74                bprm->argc++;
  75        }
  76        retval = copy_strings_kernel(1, &i_name, bprm);
  77        if (retval < 0) return retval;
  78        bprm->argc++;
  79
  80        /*
  81         * OK, now restart the process with the interpreter's inode.
  82         * Note that we use open_exec() as the name is now in kernel
  83         * space, and we don't need to copy it.
  84         */
  85        file = open_exec(interp);
  86        if (IS_ERR(file))
  87                return PTR_ERR(file);
  88
  89        bprm->file = file;
  90
  91        retval = prepare_binprm(bprm);
  92        if (retval < 0)
  93                return retval;
  94
  95        return search_binary_handler(bprm, regs);
  96}
  97
  98struct linux_binfmt em86_format = {
  99        .module         = THIS_MODULE,
 100        .load_binary    = load_em86,
 101};
 102
 103static int __init init_em86_binfmt(void)
 104{
 105        return register_binfmt(&em86_format);
 106}
 107
 108static void __exit exit_em86_binfmt(void)
 109{
 110        unregister_binfmt(&em86_format);
 111}
 112
 113module_init(init_em86_binfmt)
 114module_exit(exit_em86_binfmt)
 115MODULE_LICENSE("GPL");
 116