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
load_em86(struct linux_binprm * bprm)25 static 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
99 static struct linux_binfmt em86_format = {
100 .module = THIS_MODULE,
101 .load_binary = load_em86,
102 };
103
init_em86_binfmt(void)104 static int __init init_em86_binfmt(void)
105 {
106 register_binfmt(&em86_format);
107 return 0;
108 }
109
exit_em86_binfmt(void)110 static void __exit exit_em86_binfmt(void)
111 {
112 unregister_binfmt(&em86_format);
113 }
114
115 core_initcall(init_em86_binfmt);
116 module_exit(exit_em86_binfmt);
117 MODULE_LICENSE("GPL");
118