1/* 2 * linux/fs/binfmt_em86.c 3 * 4 * Based on linux/fs/binfmt_script.c 5 * Copyright (C) 1996 Martin von L�wis 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/slab.h> 15#include <linux/binfmts.h> 16#include <linux/elf.h> 17#include <linux/init.h> 18#include <linux/fs.h> 19#include <linux/file.h> 20#include <linux/errno.h> 21 22 23#define EM86_INTERP "/usr/bin/em86" 24#define EM86_I_NAME "em86" 25 26static int load_em86(struct linux_binprm *bprm,struct pt_regs *regs) 27{ 28 char *interp, *i_name, *i_arg; 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 || !bprm->file->f_op->mmap)) { 43 return -ENOEXEC; 44 } 45 46 bprm->sh_bang++; /* Well, the bang-shell is implicit... */ 47 allow_write_access(bprm->file); 48 fput(bprm->file); 49 bprm->file = NULL; 50 51 /* Unlike in the script case, we don't have to do any hairy 52 * parsing to find our interpreter... it's hardcoded! 53 */ 54 interp = EM86_INTERP; 55 i_name = EM86_I_NAME; 56 i_arg = NULL; /* We reserve the right to add an arg later */ 57 58 /* 59 * Splice in (1) the interpreter's name for argv[0] 60 * (2) (optional) argument to interpreter 61 * (3) filename of emulated file (replace argv[0]) 62 * 63 * This is done in reverse order, because of how the 64 * user environment and arguments are stored. 65 */ 66 remove_arg_zero(bprm); 67 retval = copy_strings_kernel(1, &bprm->filename, bprm); 68 if (retval < 0) return retval; 69 bprm->argc++; 70 if (i_arg) { 71 retval = copy_strings_kernel(1, &i_arg, bprm); 72 if (retval < 0) return retval; 73 bprm->argc++; 74 } 75 retval = copy_strings_kernel(1, &i_name, bprm); 76 if (retval < 0) return retval; 77 bprm->argc++; 78 79 /* 80 * OK, now restart the process with the interpreter's inode. 81 * Note that we use open_exec() as the name is now in kernel 82 * space, and we don't need to copy it. 83 */ 84 file = open_exec(interp); 85 if (IS_ERR(file)) 86 return PTR_ERR(file); 87 88 bprm->file = file; 89 90 retval = prepare_binprm(bprm); 91 if (retval < 0) 92 return retval; 93 94 return search_binary_handler(bprm, regs); 95} 96 97static struct linux_binfmt em86_format = { 98 .module = THIS_MODULE, 99 .load_binary = load_em86, 100}; 101 102static int __init init_em86_binfmt(void) 103{ 104 return register_binfmt(&em86_format); 105} 106 107static void __exit exit_em86_binfmt(void) 108{ 109 unregister_binfmt(&em86_format); 110} 111 112core_initcall(init_em86_binfmt); 113module_exit(exit_em86_binfmt); 114MODULE_LICENSE("GPL"); 115