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