LXR linux/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/binfmts.h>
  16#include <linux/elf.h>
  17#include <linux/init.h>
  18#include <linux/fs.h>
  19#include <linux/file.h>
  20#include <linux/errno.h>
  21
  22
  23#define EM86_INTERP     "/usr/bin/em86"
  24#define EM86_I_NAME     "em86"
  25
  26static int load_em86(struct linux_binprm *bprm,struct pt_regs *regs)
  27{
  28        char *interp, *i_name, *i_arg;
  29        struct file * file;
  30        int retval;
  31        struct elfhdr   elf_ex;
  32
  33        /* Make sure this is a Linux/Intel ELF executable... */
  34        elf_ex = *((struct elfhdr *)bprm->buf);
  35
  36        if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
  37                return  -ENOEXEC;
  38
  39        /* First of all, some simple consistency checks */
  40        if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
  41                (!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) ||
  42                (!bprm->file->f_op || !bprm->file->f_op->mmap)) {
  43                        return -ENOEXEC;
  44        }
  45
  46        bprm->sh_bang++;        /* Well, the bang-shell is implicit... */
  47        allow_write_access(bprm->file);
  48        fput(bprm->file);
  49        bprm->file = NULL;
  50
  51        /* Unlike in the script case, we don't have to do any hairy
  52         * parsing to find our interpreter... it's hardcoded!
  53         */
  54        interp = EM86_INTERP;
  55        i_name = EM86_I_NAME;
  56        i_arg = NULL;           /* We reserve the right to add an arg later */
  57
  58        /*
  59         * Splice in (1) the interpreter's name for argv[0]
  60         *           (2) (optional) argument to interpreter
  61         *           (3) filename of emulated file (replace argv[0])
  62         *
  63         * This is done in reverse order, because of how the
  64         * user environment and arguments are stored.
  65         */
  66        remove_arg_zero(bprm);
  67        retval = copy_strings_kernel(1, &bprm->filename, bprm);
  68        if (retval < 0) return retval; 
  69        bprm->argc++;
  70        if (i_arg) {
  71                retval = copy_strings_kernel(1, &i_arg, bprm);
  72                if (retval < 0) return retval; 
  73                bprm->argc++;
  74        }
  75        retval = copy_strings_kernel(1, &i_name, bprm);
  76        if (retval < 0) return retval;
  77        bprm->argc++;
  78
  79        /*
  80         * OK, now restart the process with the interpreter's inode.
  81         * Note that we use open_exec() as the name is now in kernel
  82         * space, and we don't need to copy it.
  83         */
  84        file = open_exec(interp);
  85        if (IS_ERR(file))
  86                return PTR_ERR(file);
  87
  88        bprm->file = file;
  89
  90        retval = prepare_binprm(bprm);
  91        if (retval < 0)
  92                return retval;
  93
  94        return search_binary_handler(bprm, regs);
  95}
  96
  97static struct linux_binfmt em86_format = {
  98        .module         = THIS_MODULE,
  99        .load_binary    = load_em86,
 100};
 101
 102static int __init init_em86_binfmt(void)
 103{
 104        return register_binfmt(&em86_format);
 105}
 106
 107static void __exit exit_em86_binfmt(void)
 108{
 109        unregister_binfmt(&em86_format);
 110}
 111
 112core_initcall(init_em86_binfmt);
 113module_exit(exit_em86_binfmt);
 114MODULE_LICENSE("GPL");
 115