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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> | |
14 | #include <linux/namei.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/ctype.h> | |
18 | ||
19 | MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem"); | |
20 | MODULE_AUTHOR("Carsten Paeth"); | |
21 | MODULE_LICENSE("GPL"); | |
22 | ||
23 | /* ------------------------------------------------------------------ */ | |
24 | ||
25 | static char *revision = "$Revision: 1.1.2.3 $"; | |
26 | ||
27 | /* ------------------------------------------------------------------ */ | |
28 | ||
29 | #define CAPIFS_SUPER_MAGIC (('C'<<8)|'N') | |
30 | ||
31 | static struct vfsmount *capifs_mnt; | |
32 | static struct dentry *capifs_root; | |
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; | |
52 | ||
53 | this_char = NULL; | |
54 | while ((this_char = strsep(&data, ",")) != NULL) { | |
55 | int n; | |
56 | char dummy; | |
57 | if (!*this_char) | |
58 | continue; | |
59 | if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) { | |
60 | setuid = 1; | |
61 | uid = n; | |
62 | } else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) { | |
63 | setgid = 1; | |
64 | gid = n; | |
65 | } else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1) | |
66 | mode = n & ~S_IFMT; | |
67 | else { | |
68 | printk("capifs: called with bogus options\n"); | |
69 | return -EINVAL; | |
70 | } | |
71 | } | |
72 | config.setuid = setuid; | |
73 | config.setgid = setgid; | |
74 | config.uid = uid; | |
75 | config.gid = gid; | |
76 | config.mode = mode; | |
77 | return 0; | |
78 | } | |
79 | ||
80 | static struct super_operations capifs_sops = | |
81 | { | |
82 | .statfs = simple_statfs, | |
83 | .remount_fs = capifs_remount, | |
84 | }; | |
85 | ||
86 | ||
87 | static int | |
88 | capifs_fill_super(struct super_block *s, void *data, int silent) | |
89 | { | |
90 | struct inode * inode; | |
91 | ||
92 | s->s_blocksize = 1024; | |
93 | s->s_blocksize_bits = 10; | |
94 | s->s_magic = CAPIFS_SUPER_MAGIC; | |
95 | s->s_op = &capifs_sops; | |
96 | s->s_time_gran = 1; | |
97 | ||
98 | inode = new_inode(s); | |
99 | if (!inode) | |
100 | goto fail; | |
101 | inode->i_ino = 1; | |
102 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
103 | inode->i_blocks = 0; | |
104 | inode->i_blksize = 1024; | |
105 | inode->i_uid = inode->i_gid = 0; | |
106 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR; | |
107 | inode->i_op = &simple_dir_inode_operations; | |
108 | inode->i_fop = &simple_dir_operations; | |
109 | inode->i_nlink = 2; | |
110 | ||
111 | capifs_root = s->s_root = d_alloc_root(inode); | |
112 | if (s->s_root) | |
113 | return 0; | |
114 | ||
115 | printk("capifs: get root dentry failed\n"); | |
116 | iput(inode); | |
117 | fail: | |
118 | return -ENOMEM; | |
119 | } | |
120 | ||
121 | static struct super_block *capifs_get_sb(struct file_system_type *fs_type, | |
122 | int flags, const char *dev_name, void *data) | |
123 | { | |
124 | return get_sb_single(fs_type, flags, data, capifs_fill_super); | |
125 | } | |
126 | ||
127 | static struct file_system_type capifs_fs_type = { | |
128 | .owner = THIS_MODULE, | |
129 | .name = "capifs", | |
130 | .get_sb = capifs_get_sb, | |
131 | .kill_sb = kill_anon_super, | |
132 | }; | |
133 | ||
134 | static struct dentry *get_node(int num) | |
135 | { | |
136 | char s[10]; | |
137 | struct dentry *root = capifs_root; | |
138 | down(&root->d_inode->i_sem); | |
139 | return lookup_one_len(s, root, sprintf(s, "%d", num)); | |
140 | } | |
141 | ||
142 | void capifs_new_ncci(unsigned int number, dev_t device) | |
143 | { | |
144 | struct dentry *dentry; | |
145 | struct inode *inode = new_inode(capifs_mnt->mnt_sb); | |
146 | if (!inode) | |
147 | return; | |
148 | inode->i_ino = number+2; | |
149 | inode->i_blksize = 1024; | |
150 | inode->i_uid = config.setuid ? config.uid : current->fsuid; | |
151 | inode->i_gid = config.setgid ? config.gid : current->fsgid; | |
152 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
153 | init_special_inode(inode, S_IFCHR|config.mode, device); | |
154 | //inode->i_op = &capifs_file_inode_operations; | |
155 | ||
156 | dentry = get_node(number); | |
157 | if (!IS_ERR(dentry) && !dentry->d_inode) | |
158 | d_instantiate(dentry, inode); | |
159 | up(&capifs_root->d_inode->i_sem); | |
160 | } | |
161 | ||
162 | void capifs_free_ncci(unsigned int number) | |
163 | { | |
164 | struct dentry *dentry = get_node(number); | |
165 | ||
166 | if (!IS_ERR(dentry)) { | |
167 | struct inode *inode = dentry->d_inode; | |
168 | if (inode) { | |
169 | inode->i_nlink--; | |
170 | d_delete(dentry); | |
171 | dput(dentry); | |
172 | } | |
173 | dput(dentry); | |
174 | } | |
175 | up(&capifs_root->d_inode->i_sem); | |
176 | } | |
177 | ||
178 | static int __init capifs_init(void) | |
179 | { | |
180 | char rev[32]; | |
181 | char *p; | |
182 | int err; | |
183 | ||
184 | if ((p = strchr(revision, ':')) != 0 && p[1]) { | |
185 | strlcpy(rev, p + 2, sizeof(rev)); | |
186 | if ((p = strchr(rev, '$')) != 0 && p > rev) | |
187 | *(p-1) = 0; | |
188 | } else | |
189 | strcpy(rev, "1.0"); | |
190 | ||
191 | err = register_filesystem(&capifs_fs_type); | |
192 | if (!err) { | |
193 | capifs_mnt = kern_mount(&capifs_fs_type); | |
194 | if (IS_ERR(capifs_mnt)) | |
195 | err = PTR_ERR(capifs_mnt); | |
196 | } | |
197 | if (!err) | |
198 | printk(KERN_NOTICE "capifs: Rev %s\n", rev); | |
199 | return err; | |
200 | } | |
201 | ||
202 | static void __exit capifs_exit(void) | |
203 | { | |
204 | unregister_filesystem(&capifs_fs_type); | |
205 | mntput(capifs_mnt); | |
206 | } | |
207 | ||
208 | EXPORT_SYMBOL(capifs_new_ncci); | |
209 | EXPORT_SYMBOL(capifs_free_ncci); | |
210 | ||
211 | module_init(capifs_init); | |
212 | module_exit(capifs_exit); |