1/*
2 *  xenfs.c - a filesystem for passing info between the a domain and
3 *  the hypervisor.
4 *
5 * 2008-10-07  Alex Zeffertt    Replaced /proc/xen/xenbus with xenfs filesystem
6 *                              and /proc/xen compatibility mount point.
7 *                              Turned xenfs into a loadable module.
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/kernel.h>
13#include <linux/errno.h>
14#include <linux/module.h>
15#include <linux/fs.h>
16#include <linux/magic.h>
17
18#include <xen/xen.h>
19
20#include "xenfs.h"
21#include "../privcmd.h"
22#include "../xenbus/xenbus_comms.h"
23
24#include <asm/xen/hypervisor.h>
25
26MODULE_DESCRIPTION("Xen filesystem");
27MODULE_LICENSE("GPL");
28
29static ssize_t capabilities_read(struct file *file, char __user *buf,
30				 size_t size, loff_t *off)
31{
32	char *tmp = "";
33
34	if (xen_initial_domain())
35		tmp = "control_d\n";
36
37	return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp));
38}
39
40static const struct file_operations capabilities_file_ops = {
41	.read = capabilities_read,
42	.llseek = default_llseek,
43};
44
45static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
46{
47	static struct tree_descr xenfs_files[] = {
48		[2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
49		{ "capabilities", &capabilities_file_ops, S_IRUGO },
50		{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
51		{""},
52	};
53
54	static struct tree_descr xenfs_init_files[] = {
55		[2] = { "xenbus", &xen_xenbus_fops, S_IRUSR|S_IWUSR },
56		{ "capabilities", &capabilities_file_ops, S_IRUGO },
57		{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
58		{ "xsd_kva", &xsd_kva_file_ops, S_IRUSR|S_IWUSR},
59		{ "xsd_port", &xsd_port_file_ops, S_IRUSR|S_IWUSR},
60		{""},
61	};
62
63	return simple_fill_super(sb, XENFS_SUPER_MAGIC,
64			xen_initial_domain() ? xenfs_init_files : xenfs_files);
65}
66
67static struct dentry *xenfs_mount(struct file_system_type *fs_type,
68				  int flags, const char *dev_name,
69				  void *data)
70{
71	return mount_single(fs_type, flags, data, xenfs_fill_super);
72}
73
74static struct file_system_type xenfs_type = {
75	.owner =	THIS_MODULE,
76	.name =		"xenfs",
77	.mount =	xenfs_mount,
78	.kill_sb =	kill_litter_super,
79};
80MODULE_ALIAS_FS("xenfs");
81
82static int __init xenfs_init(void)
83{
84	if (xen_domain())
85		return register_filesystem(&xenfs_type);
86
87	pr_info("not registering filesystem on non-xen platform\n");
88	return 0;
89}
90
91static void __exit xenfs_exit(void)
92{
93	if (xen_domain())
94		unregister_filesystem(&xenfs_type);
95}
96
97module_init(xenfs_init);
98module_exit(xenfs_exit);
99
100