Commit | Line | Data |
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1da177e4 LT |
1 | /* $Id: capifs.c,v 1.1.2.3 2004/01/16 21:09:26 keil Exp $ |
2 | * | |
3 | * Copyright 2000 by Carsten Paeth <calle@calle.de> | |
4 | * | |
5 | * Heavily based on devpts filesystem from H. Peter Anvin | |
6 | * | |
7 | * This software may be used and distributed according to the terms | |
8 | * of the GNU General Public License, incorporated herein by reference. | |
9 | * | |
10 | */ | |
11 | ||
12 | #include <linux/fs.h> | |
13 | #include <linux/mount.h> | |
5a0e3ad6 | 14 | #include <linux/slab.h> |
1da177e4 LT |
15 | #include <linux/namei.h> |
16 | #include <linux/module.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/ctype.h> | |
4e57b681 | 19 | #include <linux/sched.h> /* current */ |
1da177e4 | 20 | |
6e21bd9a AB |
21 | #include "capifs.h" |
22 | ||
1da177e4 LT |
23 | MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem"); |
24 | MODULE_AUTHOR("Carsten Paeth"); | |
25 | MODULE_LICENSE("GPL"); | |
26 | ||
27 | /* ------------------------------------------------------------------ */ | |
28 | ||
1da177e4 LT |
29 | #define CAPIFS_SUPER_MAGIC (('C'<<8)|'N') |
30 | ||
31 | static struct vfsmount *capifs_mnt; | |
e11e7ac1 | 32 | static int capifs_mnt_count; |
1da177e4 LT |
33 | |
34 | static struct { | |
35 | int setuid; | |
36 | int setgid; | |
37 | uid_t uid; | |
38 | gid_t gid; | |
39 | umode_t mode; | |
40 | } config = {.mode = 0600}; | |
41 | ||
42 | /* ------------------------------------------------------------------ */ | |
43 | ||
44 | static int capifs_remount(struct super_block *s, int *flags, char *data) | |
45 | { | |
46 | int setuid = 0; | |
47 | int setgid = 0; | |
48 | uid_t uid = 0; | |
49 | gid_t gid = 0; | |
50 | umode_t mode = 0600; | |
51 | char *this_char; | |
e55e212c | 52 | char *new_opt = kstrdup(data, GFP_KERNEL); |
1da177e4 LT |
53 | |
54 | this_char = NULL; | |
55 | while ((this_char = strsep(&data, ",")) != NULL) { | |
56 | int n; | |
57 | char dummy; | |
58 | if (!*this_char) | |
59 | continue; | |
60 | if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) { | |
61 | setuid = 1; | |
62 | uid = n; | |
63 | } else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) { | |
64 | setgid = 1; | |
65 | gid = n; | |
66 | } else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1) | |
67 | mode = n & ~S_IFMT; | |
68 | else { | |
c24e9b3f | 69 | kfree(new_opt); |
1da177e4 LT |
70 | printk("capifs: called with bogus options\n"); |
71 | return -EINVAL; | |
72 | } | |
73 | } | |
e55e212c | 74 | |
b0c4f322 | 75 | mutex_lock(&s->s_root->d_inode->i_mutex); |
e55e212c | 76 | |
b0c4f322 | 77 | replace_mount_options(s, new_opt); |
1da177e4 LT |
78 | config.setuid = setuid; |
79 | config.setgid = setgid; | |
80 | config.uid = uid; | |
81 | config.gid = gid; | |
82 | config.mode = mode; | |
e55e212c | 83 | |
b0c4f322 AV |
84 | mutex_unlock(&s->s_root->d_inode->i_mutex); |
85 | ||
1da177e4 LT |
86 | return 0; |
87 | } | |
88 | ||
b87221de | 89 | static const struct super_operations capifs_sops = |
1da177e4 LT |
90 | { |
91 | .statfs = simple_statfs, | |
92 | .remount_fs = capifs_remount, | |
e55e212c | 93 | .show_options = generic_show_options, |
1da177e4 LT |
94 | }; |
95 | ||
96 | ||
97 | static int | |
98 | capifs_fill_super(struct super_block *s, void *data, int silent) | |
99 | { | |
100 | struct inode * inode; | |
101 | ||
102 | s->s_blocksize = 1024; | |
103 | s->s_blocksize_bits = 10; | |
104 | s->s_magic = CAPIFS_SUPER_MAGIC; | |
105 | s->s_op = &capifs_sops; | |
106 | s->s_time_gran = 1; | |
107 | ||
108 | inode = new_inode(s); | |
109 | if (!inode) | |
110 | goto fail; | |
111 | inode->i_ino = 1; | |
112 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
1da177e4 LT |
113 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; |
114 | inode->i_op = &simple_dir_inode_operations; | |
115 | inode->i_fop = &simple_dir_operations; | |
116 | inode->i_nlink = 2; | |
117 | ||
07ad603a | 118 | s->s_root = d_alloc_root(inode); |
1da177e4 LT |
119 | if (s->s_root) |
120 | return 0; | |
121 | ||
122 | printk("capifs: get root dentry failed\n"); | |
123 | iput(inode); | |
124 | fail: | |
125 | return -ENOMEM; | |
126 | } | |
127 | ||
fc14f2fe AV |
128 | static struct dentry *capifs_mount(struct file_system_type *fs_type, |
129 | int flags, const char *dev_name, void *data) | |
1da177e4 | 130 | { |
fc14f2fe | 131 | return mount_single(fs_type, flags, data, capifs_fill_super); |
1da177e4 LT |
132 | } |
133 | ||
134 | static struct file_system_type capifs_fs_type = { | |
135 | .owner = THIS_MODULE, | |
136 | .name = "capifs", | |
fc14f2fe | 137 | .mount = capifs_mount, |
1da177e4 LT |
138 | .kill_sb = kill_anon_super, |
139 | }; | |
140 | ||
e11e7ac1 | 141 | static struct dentry *new_ncci(unsigned int number, dev_t device) |
1da177e4 | 142 | { |
07ad603a JK |
143 | struct super_block *s = capifs_mnt->mnt_sb; |
144 | struct dentry *root = s->s_root; | |
1da177e4 | 145 | struct dentry *dentry; |
c947862f | 146 | struct inode *inode; |
90926f0e JK |
147 | char name[10]; |
148 | int namelen; | |
b0c4f322 | 149 | |
07ad603a | 150 | mutex_lock(&root->d_inode->i_mutex); |
90926f0e JK |
151 | |
152 | namelen = sprintf(name, "%d", number); | |
07ad603a | 153 | dentry = lookup_one_len(name, root, namelen); |
90926f0e JK |
154 | if (IS_ERR(dentry)) { |
155 | dentry = NULL; | |
c947862f | 156 | goto unlock_out; |
90926f0e | 157 | } |
c947862f JK |
158 | |
159 | if (dentry->d_inode) { | |
160 | dput(dentry); | |
90926f0e | 161 | dentry = NULL; |
c947862f JK |
162 | goto unlock_out; |
163 | } | |
164 | ||
07ad603a | 165 | inode = new_inode(s); |
c947862f JK |
166 | if (!inode) { |
167 | dput(dentry); | |
90926f0e | 168 | dentry = NULL; |
c947862f JK |
169 | goto unlock_out; |
170 | } | |
b0c4f322 AV |
171 | |
172 | /* config contents is protected by root's i_mutex */ | |
0e164b68 DH |
173 | inode->i_uid = config.setuid ? config.uid : current_fsuid(); |
174 | inode->i_gid = config.setgid ? config.gid : current_fsgid(); | |
1da177e4 | 175 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
c947862f | 176 | inode->i_ino = number + 2; |
1da177e4 | 177 | init_special_inode(inode, S_IFCHR|config.mode, device); |
1da177e4 | 178 | |
c947862f | 179 | d_instantiate(dentry, inode); |
90926f0e | 180 | dget(dentry); |
c947862f JK |
181 | |
182 | unlock_out: | |
07ad603a | 183 | mutex_unlock(&root->d_inode->i_mutex); |
90926f0e JK |
184 | |
185 | return dentry; | |
1da177e4 LT |
186 | } |
187 | ||
e11e7ac1 JK |
188 | struct dentry *capifs_new_ncci(unsigned int number, dev_t device) |
189 | { | |
190 | struct dentry *dentry; | |
191 | ||
192 | if (simple_pin_fs(&capifs_fs_type, &capifs_mnt, &capifs_mnt_count) < 0) | |
193 | return NULL; | |
194 | ||
195 | dentry = new_ncci(number, device); | |
196 | if (!dentry) | |
197 | simple_release_fs(&capifs_mnt, &capifs_mnt_count); | |
198 | ||
199 | return dentry; | |
200 | } | |
201 | ||
90926f0e | 202 | void capifs_free_ncci(struct dentry *dentry) |
1da177e4 | 203 | { |
07ad603a | 204 | struct dentry *root = capifs_mnt->mnt_sb->s_root; |
90926f0e JK |
205 | struct inode *inode; |
206 | ||
207 | if (!dentry) | |
208 | return; | |
209 | ||
07ad603a | 210 | mutex_lock(&root->d_inode->i_mutex); |
90926f0e JK |
211 | |
212 | inode = dentry->d_inode; | |
213 | if (inode) { | |
214 | drop_nlink(inode); | |
215 | d_delete(dentry); | |
1da177e4 LT |
216 | dput(dentry); |
217 | } | |
90926f0e JK |
218 | dput(dentry); |
219 | ||
07ad603a | 220 | mutex_unlock(&root->d_inode->i_mutex); |
e11e7ac1 JK |
221 | |
222 | simple_release_fs(&capifs_mnt, &capifs_mnt_count); | |
1da177e4 LT |
223 | } |
224 | ||
225 | static int __init capifs_init(void) | |
226 | { | |
88549d6b | 227 | return register_filesystem(&capifs_fs_type); |
1da177e4 LT |
228 | } |
229 | ||
230 | static void __exit capifs_exit(void) | |
231 | { | |
232 | unregister_filesystem(&capifs_fs_type); | |
1da177e4 LT |
233 | } |
234 | ||
235 | EXPORT_SYMBOL(capifs_new_ncci); | |
236 | EXPORT_SYMBOL(capifs_free_ncci); | |
237 | ||
238 | module_init(capifs_init); | |
239 | module_exit(capifs_exit); |