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/binfmts.h>
  15#include <linux/elf.h>
  16#include <linux/init.h>
  17#include <linux/fs.h>
  18#include <linux/file.h>
  19#include <linux/errno.h>
  20
  21
  22#define EM86_INTERP     "/usr/bin/em86"
  23#define EM86_I_NAME     "em86"
  24
  25static int load_em86(struct linux_binprm *bprm)
  26{
  27        const char *i_name, *i_arg;
  28        char *interp;
  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->mmap) {
  43                        return -ENOEXEC;
  44        }
  45
  46        /* Need to be able to load the file after exec */
  47        if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
  48                return -ENOENT;
  49
  50        allow_write_access(bprm->file);
  51        fput(bprm->file);
  52        bprm->file = NULL;
  53
  54        /* Unlike in the script case, we don't have to do any hairy
  55         * parsing to find our interpreter... it's hardcoded!
  56         */
  57        interp = EM86_INTERP;
  58        i_name = EM86_I_NAME;
  59        i_arg = NULL;           /* We reserve the right to add an arg later */
  60
  61        /*
  62         * Splice in (1) the interpreter's name for argv[0]
  63         *           (2) (optional) argument to interpreter
  64         *           (3) filename of emulated file (replace argv[0])
  65         *
  66         * This is done in reverse order, because of how the
  67         * user environment and arguments are stored.
  68         */
  69        remove_arg_zero(bprm);
  70        retval = copy_strings_kernel(1, &bprm->filename, bprm);
  71        if (retval < 0) return retval; 
  72        bprm->argc++;
  73        if (i_arg) {
  74                retval = copy_strings_kernel(1, &i_arg, bprm);
  75                if (retval < 0) return retval; 
  76                bprm->argc++;
  77        }
  78        retval = copy_strings_kernel(1, &i_name, bprm);
  79        if (retval < 0) return retval;
  80        bprm->argc++;
  81
  82        /*
  83         * OK, now restart the process with the interpreter's inode.
  84         * Note that we use open_exec() as the name is now in kernel
  85         * space, and we don't need to copy it.
  86         */
  87        file = open_exec(interp);
  88        if (IS_ERR(file))
  89                return PTR_ERR(file);
  90
  91        bprm->file = file;
  92
  93        retval = prepare_binprm(bprm);
  94        if (retval < 0)
  95                return retval;
  96
  97        return search_binary_handler(bprm);
  98}
  99
 100static struct linux_binfmt em86_format = {
 101        .module         = THIS_MODULE,
 102        .load_binary    = load_em86,
 103};
 104
 105static int __init init_em86_binfmt(void)
 106{
 107        register_binfmt(&em86_format);
 108        return 0;
 109}
 110
 111static void __exit exit_em86_binfmt(void)
 112{
 113        unregister_binfmt(&em86_format);
 114}
 115
 116core_initcall(init_em86_binfmt);
 117module_exit(exit_em86_binfmt);
 118MODULE_LICENSE("GPL");
 119