1 /* $Id: capifs.c,v 1.1.2.3 2004/01/16 21:09:26 keil Exp $
3 * Copyright 2000 by Carsten Paeth <calle@calle.de>
5 * Heavily based on devpts filesystem from H. Peter Anvin
7 * This software may be used and distributed according to the terms
8 * of the GNU General Public License, incorporated herein by reference.
13 #include <linux/mount.h>
14 #include <linux/slab.h>
15 #include <linux/namei.h>
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/ctype.h>
19 #include <linux/sched.h> /* current */
23 MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem");
24 MODULE_AUTHOR("Carsten Paeth");
25 MODULE_LICENSE("GPL");
27 /* ------------------------------------------------------------------ */
29 #define CAPIFS_SUPER_MAGIC (('C'<<8)|'N')
31 static struct vfsmount *capifs_mnt;
32 static int capifs_mnt_count;
40 } config = {.mode = 0600};
42 /* ------------------------------------------------------------------ */
44 static int capifs_remount(struct super_block *s, int *flags, char *data)
52 char *new_opt = kstrdup(data, GFP_KERNEL);
55 while ((this_char = strsep(&data, ",")) != NULL) {
60 if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) {
63 } else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) {
66 } else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1)
70 printk("capifs: called with bogus options\n");
75 mutex_lock(&s->s_root->d_inode->i_mutex);
77 replace_mount_options(s, new_opt);
78 config.setuid = setuid;
79 config.setgid = setgid;
84 mutex_unlock(&s->s_root->d_inode->i_mutex);
89 static const struct super_operations capifs_sops =
91 .statfs = simple_statfs,
92 .remount_fs = capifs_remount,
93 .show_options = generic_show_options,
98 capifs_fill_super(struct super_block *s, void *data, int silent)
100 struct inode * inode;
102 s->s_blocksize = 1024;
103 s->s_blocksize_bits = 10;
104 s->s_magic = CAPIFS_SUPER_MAGIC;
105 s->s_op = &capifs_sops;
108 inode = new_inode(s);
112 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
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;
118 s->s_root = d_alloc_root(inode);
122 printk("capifs: get root dentry failed\n");
128 static int capifs_get_sb(struct file_system_type *fs_type,
129 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
131 return get_sb_single(fs_type, flags, data, capifs_fill_super, mnt);
134 static struct file_system_type capifs_fs_type = {
135 .owner = THIS_MODULE,
137 .get_sb = capifs_get_sb,
138 .kill_sb = kill_anon_super,
141 static struct dentry *new_ncci(unsigned int number, dev_t device)
143 struct super_block *s = capifs_mnt->mnt_sb;
144 struct dentry *root = s->s_root;
145 struct dentry *dentry;
150 mutex_lock(&root->d_inode->i_mutex);
152 namelen = sprintf(name, "%d", number);
153 dentry = lookup_one_len(name, root, namelen);
154 if (IS_ERR(dentry)) {
159 if (dentry->d_inode) {
165 inode = new_inode(s);
172 /* config contents is protected by root's i_mutex */
173 inode->i_uid = config.setuid ? config.uid : current_fsuid();
174 inode->i_gid = config.setgid ? config.gid : current_fsgid();
175 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
176 inode->i_ino = number + 2;
177 init_special_inode(inode, S_IFCHR|config.mode, device);
179 d_instantiate(dentry, inode);
183 mutex_unlock(&root->d_inode->i_mutex);
188 struct dentry *capifs_new_ncci(unsigned int number, dev_t device)
190 struct dentry *dentry;
192 if (simple_pin_fs(&capifs_fs_type, &capifs_mnt, &capifs_mnt_count) < 0)
195 dentry = new_ncci(number, device);
197 simple_release_fs(&capifs_mnt, &capifs_mnt_count);
202 void capifs_free_ncci(struct dentry *dentry)
204 struct dentry *root = capifs_mnt->mnt_sb->s_root;
210 mutex_lock(&root->d_inode->i_mutex);
212 inode = dentry->d_inode;
220 mutex_unlock(&root->d_inode->i_mutex);
222 simple_release_fs(&capifs_mnt, &capifs_mnt_count);
225 static int __init capifs_init(void)
227 return register_filesystem(&capifs_fs_type);
230 static void __exit capifs_exit(void)
232 unregister_filesystem(&capifs_fs_type);
235 EXPORT_SYMBOL(capifs_new_ncci);
236 EXPORT_SYMBOL(capifs_free_ncci);
238 module_init(capifs_init);
239 module_exit(capifs_exit);