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 25 static int load_em86(struct linux_binprm *bprm) 26 { 27 const char *i_name, *i_arg; 28 char *interp; 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->mmap) { 43 return -ENOEXEC; 44 } 45 46 /* Need to be able to load the file after exec */ 47 if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) 48 return -ENOENT; 49 50 allow_write_access(bprm->file); 51 fput(bprm->file); 52 bprm->file = NULL; 53 54 /* Unlike in the script case, we don't have to do any hairy 55 * parsing to find our interpreter... it's hardcoded! 56 */ 57 interp = EM86_INTERP; 58 i_name = EM86_I_NAME; 59 i_arg = NULL; /* We reserve the right to add an arg later */ 60 61 /* 62 * Splice in (1) the interpreter's name for argv[0] 63 * (2) (optional) argument to interpreter 64 * (3) filename of emulated file (replace argv[0]) 65 * 66 * This is done in reverse order, because of how the 67 * user environment and arguments are stored. 68 */ 69 remove_arg_zero(bprm); 70 retval = copy_strings_kernel(1, &bprm->filename, bprm); 71 if (retval < 0) return retval; 72 bprm->argc++; 73 if (i_arg) { 74 retval = copy_strings_kernel(1, &i_arg, bprm); 75 if (retval < 0) return retval; 76 bprm->argc++; 77 } 78 retval = copy_strings_kernel(1, &i_name, bprm); 79 if (retval < 0) return retval; 80 bprm->argc++; 81 82 /* 83 * OK, now restart the process with the interpreter's inode. 84 * Note that we use open_exec() as the name is now in kernel 85 * space, and we don't need to copy it. 86 */ 87 file = open_exec(interp); 88 if (IS_ERR(file)) 89 return PTR_ERR(file); 90 91 bprm->file = file; 92 93 retval = prepare_binprm(bprm); 94 if (retval < 0) 95 return retval; 96 97 return search_binary_handler(bprm); 98 } 99 100 static struct linux_binfmt em86_format = { 101 .module = THIS_MODULE, 102 .load_binary = load_em86, 103 }; 104 105 static int __init init_em86_binfmt(void) 106 { 107 register_binfmt(&em86_format); 108 return 0; 109 } 110 111 static void __exit exit_em86_binfmt(void) 112 { 113 unregister_binfmt(&em86_format); 114 } 115 116 core_initcall(init_em86_binfmt); 117 module_exit(exit_em86_binfmt); 118 MODULE_LICENSE("GPL"); 119
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