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 char *interp, *i_name, *i_arg; 28 struct file * file; 29 int retval; 30 struct elfhdr elf_ex; 31 32 /* Make sure this is a Linux/Intel ELF executable... */ 33 elf_ex = *((struct elfhdr *)bprm->buf); 34 35 if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0) 36 return -ENOEXEC; 37 38 /* First of all, some simple consistency checks */ 39 if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) || 40 (!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) || 41 !bprm->file->f_op->mmap) { 42 return -ENOEXEC; 43 } 44 45 /* Need to be able to load the file after exec */ 46 if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) 47 return -ENOENT; 48 49 allow_write_access(bprm->file); 50 fput(bprm->file); 51 bprm->file = NULL; 52 53 /* Unlike in the script case, we don't have to do any hairy 54 * parsing to find our interpreter... it's hardcoded! 55 */ 56 interp = EM86_INTERP; 57 i_name = EM86_I_NAME; 58 i_arg = NULL; /* We reserve the right to add an arg later */ 59 60 /* 61 * Splice in (1) the interpreter's name for argv[0] 62 * (2) (optional) argument to interpreter 63 * (3) filename of emulated file (replace argv[0]) 64 * 65 * This is done in reverse order, because of how the 66 * user environment and arguments are stored. 67 */ 68 remove_arg_zero(bprm); 69 retval = copy_strings_kernel(1, &bprm->filename, bprm); 70 if (retval < 0) return retval; 71 bprm->argc++; 72 if (i_arg) { 73 retval = copy_strings_kernel(1, &i_arg, bprm); 74 if (retval < 0) return retval; 75 bprm->argc++; 76 } 77 retval = copy_strings_kernel(1, &i_name, bprm); 78 if (retval < 0) return retval; 79 bprm->argc++; 80 81 /* 82 * OK, now restart the process with the interpreter's inode. 83 * Note that we use open_exec() as the name is now in kernel 84 * space, and we don't need to copy it. 85 */ 86 file = open_exec(interp); 87 if (IS_ERR(file)) 88 return PTR_ERR(file); 89 90 bprm->file = file; 91 92 retval = prepare_binprm(bprm); 93 if (retval < 0) 94 return retval; 95 96 return search_binary_handler(bprm); 97} 98 99static struct linux_binfmt em86_format = { 100 .module = THIS_MODULE, 101 .load_binary = load_em86, 102}; 103 104static int __init init_em86_binfmt(void) 105{ 106 register_binfmt(&em86_format); 107 return 0; 108} 109 110static void __exit exit_em86_binfmt(void) 111{ 112 unregister_binfmt(&em86_format); 113} 114 115core_initcall(init_em86_binfmt); 116module_exit(exit_em86_binfmt); 117MODULE_LICENSE("GPL"); 118