// 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");