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Commit | Line | Data |
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1107ba88 AZ |
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 | #include <linux/kernel.h> | |
11 | #include <linux/errno.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/fs.h> | |
14 | #include <linux/magic.h> | |
15 | ||
1ccbf534 JF |
16 | #include <xen/xen.h> |
17 | ||
1107ba88 AZ |
18 | #include "xenfs.h" |
19 | ||
20 | #include <asm/xen/hypervisor.h> | |
21 | ||
22 | MODULE_DESCRIPTION("Xen filesystem"); | |
23 | MODULE_LICENSE("GPL"); | |
24 | ||
655d406a IC |
25 | static struct inode *xenfs_make_inode(struct super_block *sb, int mode) |
26 | { | |
27 | struct inode *ret = new_inode(sb); | |
28 | ||
29 | if (ret) { | |
30 | ret->i_mode = mode; | |
31 | ret->i_uid = ret->i_gid = 0; | |
32 | ret->i_blocks = 0; | |
33 | ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; | |
34 | } | |
35 | return ret; | |
36 | } | |
37 | ||
38 | static struct dentry *xenfs_create_file(struct super_block *sb, | |
39 | struct dentry *parent, | |
40 | const char *name, | |
41 | const struct file_operations *fops, | |
42 | void *data, | |
43 | int mode) | |
44 | { | |
45 | struct dentry *dentry; | |
46 | struct inode *inode; | |
47 | ||
48 | dentry = d_alloc_name(parent, name); | |
49 | if (!dentry) | |
50 | return NULL; | |
51 | ||
52 | inode = xenfs_make_inode(sb, S_IFREG | mode); | |
53 | if (!inode) { | |
54 | dput(dentry); | |
55 | return NULL; | |
56 | } | |
57 | ||
58 | inode->i_fop = fops; | |
59 | inode->i_private = data; | |
60 | ||
61 | d_add(dentry, inode); | |
62 | return dentry; | |
63 | } | |
64 | ||
818fd206 JF |
65 | static ssize_t capabilities_read(struct file *file, char __user *buf, |
66 | size_t size, loff_t *off) | |
67 | { | |
68 | char *tmp = ""; | |
69 | ||
70 | if (xen_initial_domain()) | |
71 | tmp = "control_d\n"; | |
72 | ||
73 | return simple_read_from_buffer(buf, size, off, tmp, strlen(tmp)); | |
74 | } | |
75 | ||
76 | static const struct file_operations capabilities_file_ops = { | |
77 | .read = capabilities_read, | |
6038f373 | 78 | .llseek = default_llseek, |
818fd206 JF |
79 | }; |
80 | ||
1107ba88 AZ |
81 | static int xenfs_fill_super(struct super_block *sb, void *data, int silent) |
82 | { | |
83 | static struct tree_descr xenfs_files[] = { | |
818fd206 JF |
84 | [1] = {}, |
85 | { "xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR }, | |
86 | { "capabilities", &capabilities_file_ops, S_IRUGO }, | |
9387377e | 87 | { "privcmd", &privcmd_file_ops, S_IRUSR|S_IWUSR }, |
1107ba88 AZ |
88 | {""}, |
89 | }; | |
655d406a | 90 | int rc; |
1107ba88 | 91 | |
655d406a IC |
92 | rc = simple_fill_super(sb, XENFS_SUPER_MAGIC, xenfs_files); |
93 | if (rc < 0) | |
94 | return rc; | |
95 | ||
96 | if (xen_initial_domain()) { | |
97 | xenfs_create_file(sb, sb->s_root, "xsd_kva", | |
98 | &xsd_kva_file_ops, NULL, S_IRUSR|S_IWUSR); | |
99 | xenfs_create_file(sb, sb->s_root, "xsd_port", | |
100 | &xsd_port_file_ops, NULL, S_IRUSR|S_IWUSR); | |
101 | } | |
1107ba88 | 102 | |
655d406a | 103 | return rc; |
1107ba88 AZ |
104 | } |
105 | ||
fe61f1d7 JF |
106 | static struct dentry *xenfs_mount(struct file_system_type *fs_type, |
107 | int flags, const char *dev_name, | |
108 | void *data) | |
1107ba88 | 109 | { |
fc14f2fe | 110 | return mount_single(fs_type, flags, data, xenfs_fill_super); |
1107ba88 AZ |
111 | } |
112 | ||
113 | static struct file_system_type xenfs_type = { | |
114 | .owner = THIS_MODULE, | |
115 | .name = "xenfs", | |
fc14f2fe | 116 | .mount = xenfs_mount, |
1107ba88 AZ |
117 | .kill_sb = kill_litter_super, |
118 | }; | |
119 | ||
120 | static int __init xenfs_init(void) | |
121 | { | |
9045d47e JF |
122 | if (xen_domain()) |
123 | return register_filesystem(&xenfs_type); | |
1107ba88 | 124 | |
9045d47e JF |
125 | printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n"); |
126 | return 0; | |
1107ba88 AZ |
127 | } |
128 | ||
129 | static void __exit xenfs_exit(void) | |
130 | { | |
43df95c4 | 131 | if (xen_domain()) |
1107ba88 AZ |
132 | unregister_filesystem(&xenfs_type); |
133 | } | |
134 | ||
135 | module_init(xenfs_init); | |
136 | module_exit(xenfs_exit); | |
137 |