Commit | Line | Data |
---|---|---|
bafa9654 MS |
1 | /* |
2 | FUSE: Filesystem in Userspace | |
1729a16c | 3 | Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> |
bafa9654 MS |
4 | |
5 | This program can be distributed under the terms of the GNU GPL. | |
6 | See the file COPYING. | |
7 | */ | |
8 | ||
9 | #include "fuse_i.h" | |
10 | ||
11 | #include <linux/init.h> | |
12 | #include <linux/module.h> | |
13 | ||
14 | #define FUSE_CTL_SUPER_MAGIC 0x65735543 | |
15 | ||
16 | /* | |
17 | * This is non-NULL when the single instance of the control filesystem | |
18 | * exists. Protected by fuse_mutex | |
19 | */ | |
20 | static struct super_block *fuse_control_sb; | |
21 | ||
22 | static struct fuse_conn *fuse_ctl_file_conn_get(struct file *file) | |
23 | { | |
24 | struct fuse_conn *fc; | |
25 | mutex_lock(&fuse_mutex); | |
7706a9d6 | 26 | fc = file->f_path.dentry->d_inode->i_private; |
bafa9654 MS |
27 | if (fc) |
28 | fc = fuse_conn_get(fc); | |
29 | mutex_unlock(&fuse_mutex); | |
30 | return fc; | |
31 | } | |
32 | ||
33 | static ssize_t fuse_conn_abort_write(struct file *file, const char __user *buf, | |
34 | size_t count, loff_t *ppos) | |
35 | { | |
36 | struct fuse_conn *fc = fuse_ctl_file_conn_get(file); | |
37 | if (fc) { | |
38 | fuse_abort_conn(fc); | |
39 | fuse_conn_put(fc); | |
40 | } | |
41 | return count; | |
42 | } | |
43 | ||
44 | static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf, | |
45 | size_t len, loff_t *ppos) | |
46 | { | |
47 | char tmp[32]; | |
48 | size_t size; | |
49 | ||
50 | if (!*ppos) { | |
1729a16c | 51 | long value; |
bafa9654 MS |
52 | struct fuse_conn *fc = fuse_ctl_file_conn_get(file); |
53 | if (!fc) | |
54 | return 0; | |
55 | ||
1729a16c MS |
56 | value = atomic_read(&fc->num_waiting); |
57 | file->private_data = (void *)value; | |
bafa9654 MS |
58 | fuse_conn_put(fc); |
59 | } | |
60 | size = sprintf(tmp, "%ld\n", (long)file->private_data); | |
61 | return simple_read_from_buffer(buf, len, ppos, tmp, size); | |
62 | } | |
63 | ||
64 | static const struct file_operations fuse_ctl_abort_ops = { | |
65 | .open = nonseekable_open, | |
66 | .write = fuse_conn_abort_write, | |
67 | }; | |
68 | ||
69 | static const struct file_operations fuse_ctl_waiting_ops = { | |
70 | .open = nonseekable_open, | |
71 | .read = fuse_conn_waiting_read, | |
72 | }; | |
73 | ||
74 | static struct dentry *fuse_ctl_add_dentry(struct dentry *parent, | |
75 | struct fuse_conn *fc, | |
76 | const char *name, | |
77 | int mode, int nlink, | |
754661f1 | 78 | const struct inode_operations *iop, |
bafa9654 MS |
79 | const struct file_operations *fop) |
80 | { | |
81 | struct dentry *dentry; | |
82 | struct inode *inode; | |
83 | ||
84 | BUG_ON(fc->ctl_ndents >= FUSE_CTL_NUM_DENTRIES); | |
85 | dentry = d_alloc_name(parent, name); | |
86 | if (!dentry) | |
87 | return NULL; | |
88 | ||
89 | fc->ctl_dentry[fc->ctl_ndents++] = dentry; | |
90 | inode = new_inode(fuse_control_sb); | |
91 | if (!inode) | |
92 | return NULL; | |
93 | ||
94 | inode->i_mode = mode; | |
95 | inode->i_uid = fc->user_id; | |
96 | inode->i_gid = fc->group_id; | |
97 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
98 | /* setting ->i_op to NULL is not allowed */ | |
99 | if (iop) | |
100 | inode->i_op = iop; | |
101 | inode->i_fop = fop; | |
102 | inode->i_nlink = nlink; | |
8e18e294 | 103 | inode->i_private = fc; |
bafa9654 MS |
104 | d_add(dentry, inode); |
105 | return dentry; | |
106 | } | |
107 | ||
108 | /* | |
109 | * Add a connection to the control filesystem (if it exists). Caller | |
873302c7 | 110 | * must hold fuse_mutex |
bafa9654 MS |
111 | */ |
112 | int fuse_ctl_add_conn(struct fuse_conn *fc) | |
113 | { | |
114 | struct dentry *parent; | |
115 | char name[32]; | |
116 | ||
117 | if (!fuse_control_sb) | |
118 | return 0; | |
119 | ||
120 | parent = fuse_control_sb->s_root; | |
d8c76e6f | 121 | inc_nlink(parent->d_inode); |
b6f2fcbc | 122 | sprintf(name, "%u", fc->dev); |
bafa9654 MS |
123 | parent = fuse_ctl_add_dentry(parent, fc, name, S_IFDIR | 0500, 2, |
124 | &simple_dir_inode_operations, | |
125 | &simple_dir_operations); | |
126 | if (!parent) | |
127 | goto err; | |
128 | ||
129 | if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG | 0400, 1, | |
130 | NULL, &fuse_ctl_waiting_ops) || | |
131 | !fuse_ctl_add_dentry(parent, fc, "abort", S_IFREG | 0200, 1, | |
132 | NULL, &fuse_ctl_abort_ops)) | |
133 | goto err; | |
134 | ||
135 | return 0; | |
136 | ||
137 | err: | |
138 | fuse_ctl_remove_conn(fc); | |
139 | return -ENOMEM; | |
140 | } | |
141 | ||
142 | /* | |
143 | * Remove a connection from the control filesystem (if it exists). | |
873302c7 | 144 | * Caller must hold fuse_mutex |
bafa9654 MS |
145 | */ |
146 | void fuse_ctl_remove_conn(struct fuse_conn *fc) | |
147 | { | |
148 | int i; | |
149 | ||
150 | if (!fuse_control_sb) | |
151 | return; | |
152 | ||
153 | for (i = fc->ctl_ndents - 1; i >= 0; i--) { | |
154 | struct dentry *dentry = fc->ctl_dentry[i]; | |
8e18e294 | 155 | dentry->d_inode->i_private = NULL; |
bafa9654 MS |
156 | d_drop(dentry); |
157 | dput(dentry); | |
158 | } | |
159 | fuse_control_sb->s_root->d_inode->i_nlink--; | |
160 | } | |
161 | ||
162 | static int fuse_ctl_fill_super(struct super_block *sb, void *data, int silent) | |
163 | { | |
164 | struct tree_descr empty_descr = {""}; | |
165 | struct fuse_conn *fc; | |
166 | int err; | |
167 | ||
168 | err = simple_fill_super(sb, FUSE_CTL_SUPER_MAGIC, &empty_descr); | |
169 | if (err) | |
170 | return err; | |
171 | ||
172 | mutex_lock(&fuse_mutex); | |
173 | BUG_ON(fuse_control_sb); | |
174 | fuse_control_sb = sb; | |
175 | list_for_each_entry(fc, &fuse_conn_list, entry) { | |
176 | err = fuse_ctl_add_conn(fc); | |
177 | if (err) { | |
178 | fuse_control_sb = NULL; | |
179 | mutex_unlock(&fuse_mutex); | |
180 | return err; | |
181 | } | |
182 | } | |
183 | mutex_unlock(&fuse_mutex); | |
184 | ||
185 | return 0; | |
186 | } | |
187 | ||
188 | static int fuse_ctl_get_sb(struct file_system_type *fs_type, int flags, | |
189 | const char *dev_name, void *raw_data, | |
190 | struct vfsmount *mnt) | |
191 | { | |
192 | return get_sb_single(fs_type, flags, raw_data, | |
193 | fuse_ctl_fill_super, mnt); | |
194 | } | |
195 | ||
196 | static void fuse_ctl_kill_sb(struct super_block *sb) | |
197 | { | |
ff795447 MS |
198 | struct fuse_conn *fc; |
199 | ||
bafa9654 MS |
200 | mutex_lock(&fuse_mutex); |
201 | fuse_control_sb = NULL; | |
ff795447 MS |
202 | list_for_each_entry(fc, &fuse_conn_list, entry) |
203 | fc->ctl_ndents = 0; | |
bafa9654 MS |
204 | mutex_unlock(&fuse_mutex); |
205 | ||
206 | kill_litter_super(sb); | |
207 | } | |
208 | ||
209 | static struct file_system_type fuse_ctl_fs_type = { | |
210 | .owner = THIS_MODULE, | |
211 | .name = "fusectl", | |
212 | .get_sb = fuse_ctl_get_sb, | |
213 | .kill_sb = fuse_ctl_kill_sb, | |
214 | }; | |
215 | ||
216 | int __init fuse_ctl_init(void) | |
217 | { | |
218 | return register_filesystem(&fuse_ctl_fs_type); | |
219 | } | |
220 | ||
221 | void fuse_ctl_cleanup(void) | |
222 | { | |
223 | unregister_filesystem(&fuse_ctl_fs_type); | |
224 | } |