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