Skip to content
This repository
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 114 lines (95 sloc) 2.824 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113
/*
* 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/binfmts.h>
#include <linux/elf.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/errno.h>


#define EM86_INTERP "/usr/bin/em86"
#define EM86_I_NAME "em86"

static int load_em86(struct linux_binprm *bprm,struct pt_regs *regs)
{
char *interp, *i_name, *i_arg;
struct file * file;
int retval;
struct elfhdr elf_ex;

/* Make sure this is a Linux/Intel ELF executable... */
elf_ex = *((struct elfhdr *)bprm->buf);

if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 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->file->f_op || !bprm->file->f_op->mmap)) {
return -ENOEXEC;
}

bprm->recursion_depth++; /* Well, the bang-shell is implicit... */
allow_write_access(bprm->file);
fput(bprm->file);
bprm->file = NULL;

/* 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);
retval = copy_strings_kernel(1, &bprm->filename, bprm);
if (retval < 0) return retval;
bprm->argc++;
if (i_arg) {
retval = copy_strings_kernel(1, &i_arg, bprm);
if (retval < 0) return retval;
bprm->argc++;
}
retval = copy_strings_kernel(1, &i_name, bprm);
if (retval < 0) return retval;
bprm->argc++;

/*
* OK, now restart the process with the interpreter's inode.
* Note that we use open_exec() as the name is now in kernel
* space, and we don't need to copy it.
*/
file = open_exec(interp);
if (IS_ERR(file))
return PTR_ERR(file);

bprm->file = file;

retval = prepare_binprm(bprm);
if (retval < 0)
return retval;

return search_binary_handler(bprm, regs);
}

static struct linux_binfmt em86_format = {
.module = THIS_MODULE,
.load_binary = load_em86,
};

static int __init init_em86_binfmt(void)
{
return register_binfmt(&em86_format);
}

static void __exit exit_em86_binfmt(void)
{
unregister_binfmt(&em86_format);
}

core_initcall(init_em86_binfmt);
module_exit(exit_em86_binfmt);
MODULE_LICENSE("GPL");
Something went wrong with that request. Please try again.