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/* $Id: capifs.c,v 1.1.2.3 2004/01/16 21:09:26 keil Exp $
*
* Copyright 2000 by Carsten Paeth <calle@calle.de>
*
* Heavily based on devpts filesystem from H. Peter Anvin
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*
*/
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/ctype.h>
#include <linux/sched.h> /* current */
#include "capifs.h"
MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem");
MODULE_AUTHOR("Carsten Paeth");
MODULE_LICENSE("GPL");
/* ------------------------------------------------------------------ */
#define CAPIFS_SUPER_MAGIC (('C'<<8)|'N')
static struct vfsmount *capifs_mnt;
static int capifs_mnt_count;
static struct {
int setuid;
int setgid;
uid_t uid;
gid_t gid;
umode_t mode;
} config = {.mode = 0600};
/* ------------------------------------------------------------------ */
static int capifs_remount(struct super_block *s, int *flags, char *data)
{
int setuid = 0;
int setgid = 0;
uid_t uid = 0;
gid_t gid = 0;
umode_t mode = 0600;
char *this_char;
char *new_opt = kstrdup(data, GFP_KERNEL);
this_char = NULL;
while ((this_char = strsep(&data, ",")) != NULL) {
int n;
char dummy;
if (!*this_char)
continue;
if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) {
setuid = 1;
uid = n;
} else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) {
setgid = 1;
gid = n;
} else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1)
mode = n & ~S_IFMT;
else {
kfree(new_opt);
printk("capifs: called with bogus options\n");
return -EINVAL;
}
}
mutex_lock(&s->s_root->d_inode->i_mutex);
replace_mount_options(s, new_opt);
config.setuid = setuid;
config.setgid = setgid;
config.uid = uid;
config.gid = gid;
config.mode = mode;
mutex_unlock(&s->s_root->d_inode->i_mutex);
return 0;
}
static const struct super_operations capifs_sops =
{
.statfs = simple_statfs,
.remount_fs = capifs_remount,
.show_options = generic_show_options,
};
static int
capifs_fill_super(struct super_block *s, void *data, int silent)
{
struct inode * inode;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = CAPIFS_SUPER_MAGIC;
s->s_op = &capifs_sops;
s->s_time_gran = 1;
inode = new_inode(s);
if (!inode)
goto fail;
inode->i_ino = 1;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
inode->i_nlink = 2;
s->s_root = d_alloc_root(inode);
if (s->s_root)
return 0;
printk("capifs: get root dentry failed\n");
iput(inode);
fail:
return -ENOMEM;
}
static int capifs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_single(fs_type, flags, data, capifs_fill_super, mnt);
}
static struct file_system_type capifs_fs_type = {
.owner = THIS_MODULE,
.name = "capifs",
.get_sb = capifs_get_sb,
.kill_sb = kill_anon_super,
};
static struct dentry *new_ncci(unsigned int number, dev_t device)
{
struct super_block *s = capifs_mnt->mnt_sb;
struct dentry *root = s->s_root;
struct dentry *dentry;
struct inode *inode;
char name[10];
int namelen;
mutex_lock(&root->d_inode->i_mutex);
namelen = sprintf(name, "%d", number);
dentry = lookup_one_len(name, root, namelen);
if (IS_ERR(dentry)) {
dentry = NULL;
goto unlock_out;
}
if (dentry->d_inode) {
dput(dentry);
dentry = NULL;
goto unlock_out;
}
inode = new_inode(s);
if (!inode) {
dput(dentry);
dentry = NULL;
goto unlock_out;
}
/* config contents is protected by root's i_mutex */
inode->i_uid = config.setuid ? config.uid : current_fsuid();
inode->i_gid = config.setgid ? config.gid : current_fsgid();
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->i_ino = number + 2;
init_special_inode(inode, S_IFCHR|config.mode, device);
d_instantiate(dentry, inode);
dget(dentry);
unlock_out:
mutex_unlock(&root->d_inode->i_mutex);
return dentry;
}
struct dentry *capifs_new_ncci(unsigned int number, dev_t device)
{
struct dentry *dentry;
if (simple_pin_fs(&capifs_fs_type, &capifs_mnt, &capifs_mnt_count) < 0)
return NULL;
dentry = new_ncci(number, device);
if (!dentry)
simple_release_fs(&capifs_mnt, &capifs_mnt_count);
return dentry;
}
void capifs_free_ncci(struct dentry *dentry)
{
struct dentry *root = capifs_mnt->mnt_sb->s_root;
struct inode *inode;
if (!dentry)
return;
mutex_lock(&root->d_inode->i_mutex);
inode = dentry->d_inode;
if (inode) {
drop_nlink(inode);
d_delete(dentry);
dput(dentry);
}
dput(dentry);
mutex_unlock(&root->d_inode->i_mutex);
simple_release_fs(&capifs_mnt, &capifs_mnt_count);
}
static int __init capifs_init(void)
{
return register_filesystem(&capifs_fs_type);
}
static void __exit capifs_exit(void)
{
unregister_filesystem(&capifs_fs_type);
}
EXPORT_SYMBOL(capifs_new_ncci);
EXPORT_SYMBOL(capifs_free_ncci);
module_init(capifs_init);
module_exit(capifs_exit);
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