tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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#include <linux/sched.h> /* current */
19
20#include "capifs.h"
21
22MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem");
23MODULE_AUTHOR("Carsten Paeth");
24MODULE_LICENSE("GPL");
25
26/* ------------------------------------------------------------------ */
27
28static char *revision = "$Revision: 1.1.2.3 $";
29
30/* ------------------------------------------------------------------ */
31
32#define CAPIFS_SUPER_MAGIC (('C'<<8)|'N')
33
34static struct vfsmount *capifs_mnt;
35static struct dentry *capifs_root;
36
37static struct {
38 int setuid;
39 int setgid;
40 uid_t uid;
41 gid_t gid;
42 umode_t mode;
43} config = {.mode = 0600};
44
45/* ------------------------------------------------------------------ */
46
47static int capifs_remount(struct super_block *s, int *flags, char *data)
48{
49 int setuid = 0;
50 int setgid = 0;
51 uid_t uid = 0;
52 gid_t gid = 0;
53 umode_t mode = 0600;
54 char *this_char;
55
56 this_char = NULL;
57 while ((this_char = strsep(&data, ",")) != NULL) {
58 int n;
59 char dummy;
60 if (!*this_char)
61 continue;
62 if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) {
63 setuid = 1;
64 uid = n;
65 } else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) {
66 setgid = 1;
67 gid = n;
68 } else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1)
69 mode = n & ~S_IFMT;
70 else {
71 printk("capifs: called with bogus options\n");
72 return -EINVAL;
73 }
74 }
75 config.setuid = setuid;
76 config.setgid = setgid;
77 config.uid = uid;
78 config.gid = gid;
79 config.mode = mode;
80 return 0;
81}
82
83static struct super_operations capifs_sops =
84{
85 .statfs = simple_statfs,
86 .remount_fs = capifs_remount,
87};
88
89
90static int
91capifs_fill_super(struct super_block *s, void *data, int silent)
92{
93 struct inode * inode;
94
95 s->s_blocksize = 1024;
96 s->s_blocksize_bits = 10;
97 s->s_magic = CAPIFS_SUPER_MAGIC;
98 s->s_op = &capifs_sops;
99 s->s_time_gran = 1;
100
101 inode = new_inode(s);
102 if (!inode)
103 goto fail;
104 inode->i_ino = 1;
105 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
106 inode->i_blocks = 0;
107 inode->i_uid = inode->i_gid = 0;
108 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
109 inode->i_op = &simple_dir_inode_operations;
110 inode->i_fop = &simple_dir_operations;
111 inode->i_nlink = 2;
112
113 capifs_root = s->s_root = d_alloc_root(inode);
114 if (s->s_root)
115 return 0;
116
117 printk("capifs: get root dentry failed\n");
118 iput(inode);
119fail:
120 return -ENOMEM;
121}
122
123static int capifs_get_sb(struct file_system_type *fs_type,
124 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
125{
126 return get_sb_single(fs_type, flags, data, capifs_fill_super, mnt);
127}
128
129static struct file_system_type capifs_fs_type = {
130 .owner = THIS_MODULE,
131 .name = "capifs",
132 .get_sb = capifs_get_sb,
133 .kill_sb = kill_anon_super,
134};
135
136static struct dentry *get_node(int num)
137{
138 char s[10];
139 struct dentry *root = capifs_root;
140 mutex_lock(&root->d_inode->i_mutex);
141 return lookup_one_len(s, root, sprintf(s, "%d", num));
142}
143
144void capifs_new_ncci(unsigned int number, dev_t device)
145{
146 struct dentry *dentry;
147 struct inode *inode = new_inode(capifs_mnt->mnt_sb);
148 if (!inode)
149 return;
150 inode->i_ino = number+2;
151 inode->i_uid = config.setuid ? config.uid : current->fsuid;
152 inode->i_gid = config.setgid ? config.gid : current->fsgid;
153 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
154 init_special_inode(inode, S_IFCHR|config.mode, device);
155 //inode->i_op = &capifs_file_inode_operations;
156
157 dentry = get_node(number);
158 if (!IS_ERR(dentry) && !dentry->d_inode)
159 d_instantiate(dentry, inode);
160 mutex_unlock(&capifs_root->d_inode->i_mutex);
161}
162
163void capifs_free_ncci(unsigned int number)
164{
165 struct dentry *dentry = get_node(number);
166
167 if (!IS_ERR(dentry)) {
168 struct inode *inode = dentry->d_inode;
169 if (inode) {
170 inode->i_nlink--;
171 d_delete(dentry);
172 dput(dentry);
173 }
174 dput(dentry);
175 }
176 mutex_unlock(&capifs_root->d_inode->i_mutex);
177}
178
179static int __init capifs_init(void)
180{
181 char rev[32];
182 char *p;
183 int err;
184
185 if ((p = strchr(revision, ':')) != 0 && p[1]) {
186 strlcpy(rev, p + 2, sizeof(rev));
187 if ((p = strchr(rev, '$')) != 0 && p > rev)
188 *(p-1) = 0;
189 } else
190 strcpy(rev, "1.0");
191
192 err = register_filesystem(&capifs_fs_type);
193 if (!err) {
194 capifs_mnt = kern_mount(&capifs_fs_type);
195 if (IS_ERR(capifs_mnt)) {
196 err = PTR_ERR(capifs_mnt);
197 unregister_filesystem(&capifs_fs_type);
198 }
199 }
200 if (!err)
201 printk(KERN_NOTICE "capifs: Rev %s\n", rev);
202 return err;
203}
204
205static void __exit capifs_exit(void)
206{
207 unregister_filesystem(&capifs_fs_type);
208 mntput(capifs_mnt);
209}
210
211EXPORT_SYMBOL(capifs_new_ncci);
212EXPORT_SYMBOL(capifs_free_ncci);
213
214module_init(capifs_init);
215module_exit(capifs_exit);