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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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)
{
const char *i_name, *i_arg;
char *interp;
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->mmap) {
return -ENOEXEC;
}
/* Need to be able to load the file after exec */
if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
return -ENOENT;
/* 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_string_kernel(bprm->filename, bprm);
if (retval < 0) return retval;
bprm->argc++;
if (i_arg) {
retval = copy_string_kernel(i_arg, bprm);
if (retval < 0) return retval;
bprm->argc++;
}
retval = copy_string_kernel(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->interpreter = file;
return 0;
}
static struct linux_binfmt em86_format = {
.module = THIS_MODULE,
.load_binary = load_em86,
};
static int __init init_em86_binfmt(void)
{
register_binfmt(&em86_format);
return 0;
}
static void __exit exit_em86_binfmt(void)
{
unregister_binfmt(&em86_format);
}
core_initcall(init_em86_binfmt);
module_exit(exit_em86_binfmt);
MODULE_LICENSE("GPL");
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