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linux/drivers/usb/core/inode.c

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/*****************************************************************************/
/*
* inode.c -- Inode/Dentry functions for the USB device file system.
*
* Copyright (C) 2000 Thomas Sailer (sailer@ife.ee.ethz.ch)
* Copyright (C) 2001,2002,2004 Greg Kroah-Hartman (greg@kroah.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* History:
* 0.1 04.01.2000 Created
* 0.2 10.12.2001 converted to use the vfs layer better
*/
/*****************************************************************************/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/usb.h>
#include <linux/namei.h>
#include <linux/usbdevice_fs.h>
#include <linux/parser.h>
#include <linux/notifier.h>
#include <linux/seq_file.h>
#include <linux/smp_lock.h>
#include <linux/usb/hcd.h>
#include <asm/byteorder.h>
#include "usb.h"
#define USBFS_DEFAULT_DEVMODE (S_IWUSR | S_IRUGO)
#define USBFS_DEFAULT_BUSMODE (S_IXUGO | S_IRUGO)
#define USBFS_DEFAULT_LISTMODE S_IRUGO
static const struct file_operations default_file_operations;
static struct vfsmount *usbfs_mount;
static int usbfs_mount_count; /* = 0 */
static int ignore_mount = 0;
static struct dentry *devices_usbfs_dentry;
static int num_buses; /* = 0 */
static uid_t devuid; /* = 0 */
static uid_t busuid; /* = 0 */
static uid_t listuid; /* = 0 */
static gid_t devgid; /* = 0 */
static gid_t busgid; /* = 0 */
static gid_t listgid; /* = 0 */
static umode_t devmode = USBFS_DEFAULT_DEVMODE;
static umode_t busmode = USBFS_DEFAULT_BUSMODE;
static umode_t listmode = USBFS_DEFAULT_LISTMODE;
static int usbfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
{
if (devuid != 0)
seq_printf(seq, ",devuid=%u", devuid);
if (devgid != 0)
seq_printf(seq, ",devgid=%u", devgid);
if (devmode != USBFS_DEFAULT_DEVMODE)
seq_printf(seq, ",devmode=%o", devmode);
if (busuid != 0)
seq_printf(seq, ",busuid=%u", busuid);
if (busgid != 0)
seq_printf(seq, ",busgid=%u", busgid);
if (busmode != USBFS_DEFAULT_BUSMODE)
seq_printf(seq, ",busmode=%o", busmode);
if (listuid != 0)
seq_printf(seq, ",listuid=%u", listuid);
if (listgid != 0)
seq_printf(seq, ",listgid=%u", listgid);
if (listmode != USBFS_DEFAULT_LISTMODE)
seq_printf(seq, ",listmode=%o", listmode);
return 0;
}
enum {
Opt_devuid, Opt_devgid, Opt_devmode,
Opt_busuid, Opt_busgid, Opt_busmode,
Opt_listuid, Opt_listgid, Opt_listmode,
Opt_err,
};
static const match_table_t tokens = {
{Opt_devuid, "devuid=%u"},
{Opt_devgid, "devgid=%u"},
{Opt_devmode, "devmode=%o"},
{Opt_busuid, "busuid=%u"},
{Opt_busgid, "busgid=%u"},
{Opt_busmode, "busmode=%o"},
{Opt_listuid, "listuid=%u"},
{Opt_listgid, "listgid=%u"},
{Opt_listmode, "listmode=%o"},
{Opt_err, NULL}
};
static int parse_options(struct super_block *s, char *data)
{
char *p;
int option;
/* (re)set to defaults. */
devuid = 0;
busuid = 0;
listuid = 0;
devgid = 0;
busgid = 0;
listgid = 0;
devmode = USBFS_DEFAULT_DEVMODE;
busmode = USBFS_DEFAULT_BUSMODE;
listmode = USBFS_DEFAULT_LISTMODE;
while ((p = strsep(&data, ",")) != NULL) {
substring_t args[MAX_OPT_ARGS];
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_devuid:
if (match_int(&args[0], &option))
return -EINVAL;
devuid = option;
break;
case Opt_devgid:
if (match_int(&args[0], &option))
return -EINVAL;
devgid = option;
break;
case Opt_devmode:
if (match_octal(&args[0], &option))
return -EINVAL;
devmode = option & S_IRWXUGO;
break;
case Opt_busuid:
if (match_int(&args[0], &option))
return -EINVAL;
busuid = option;
break;
case Opt_busgid:
if (match_int(&args[0], &option))
return -EINVAL;
busgid = option;
break;
case Opt_busmode:
if (match_octal(&args[0], &option))
return -EINVAL;
busmode = option & S_IRWXUGO;
break;
case Opt_listuid:
if (match_int(&args[0], &option))
return -EINVAL;
listuid = option;
break;
case Opt_listgid:
if (match_int(&args[0], &option))
return -EINVAL;
listgid = option;
break;
case Opt_listmode:
if (match_octal(&args[0], &option))
return -EINVAL;
listmode = option & S_IRWXUGO;
break;
default:
printk(KERN_ERR "usbfs: unrecognised mount option "
"\"%s\" or missing value\n", p);
return -EINVAL;
}
}
return 0;
}
static void update_special(struct dentry *special)
{
special->d_inode->i_uid = listuid;
special->d_inode->i_gid = listgid;
special->d_inode->i_mode = S_IFREG | listmode;
}
static void update_dev(struct dentry *dev)
{
dev->d_inode->i_uid = devuid;
dev->d_inode->i_gid = devgid;
dev->d_inode->i_mode = S_IFREG | devmode;
}
static void update_bus(struct dentry *bus)
{
struct dentry *dev = NULL;
bus->d_inode->i_uid = busuid;
bus->d_inode->i_gid = busgid;
bus->d_inode->i_mode = S_IFDIR | busmode;
mutex_lock(&bus->d_inode->i_mutex);
list_for_each_entry(dev, &bus->d_subdirs, d_u.d_child)
if (dev->d_inode)
update_dev(dev);
mutex_unlock(&bus->d_inode->i_mutex);
}
static void update_sb(struct super_block *sb)
{
struct dentry *root = sb->s_root;
struct dentry *bus = NULL;
if (!root)
return;
mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_PARENT);
list_for_each_entry(bus, &root->d_subdirs, d_u.d_child) {
if (bus->d_inode) {
switch (S_IFMT & bus->d_inode->i_mode) {
case S_IFDIR:
update_bus(bus);
break;
case S_IFREG:
update_special(bus);
break;
default:
printk(KERN_WARNING "usbfs: Unknown node %s "
"mode %x found on remount!\n",
bus->d_name.name, bus->d_inode->i_mode);
break;
}
}
}
mutex_unlock(&root->d_inode->i_mutex);
}
static int remount(struct super_block *sb, int *flags, char *data)
{
/* If this is not a real mount,
* i.e. it's a simple_pin_fs from create_special_files,
* then ignore it.
*/
if (ignore_mount)
return 0;
if (parse_options(sb, data)) {
printk(KERN_WARNING "usbfs: mount parameter error.\n");
return -EINVAL;
}
if (usbfs_mount && usbfs_mount->mnt_sb)
update_sb(usbfs_mount->mnt_sb);
return 0;
}
static struct inode *usbfs_get_inode (struct super_block *sb, int mode, dev_t dev)
{
struct inode *inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
switch (mode & S_IFMT) {
default:
init_special_inode(inode, mode, dev);
break;
case S_IFREG:
inode->i_fop = &default_file_operations;
break;
case S_IFDIR:
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);
break;
}
}
return inode;
}
/* SMP-safe */
static int usbfs_mknod (struct inode *dir, struct dentry *dentry, int mode,
dev_t dev)
{
struct inode *inode = usbfs_get_inode(dir->i_sb, mode, dev);
int error = -EPERM;
if (dentry->d_inode)
return -EEXIST;
if (inode) {
d_instantiate(dentry, inode);
dget(dentry);
error = 0;
}
return error;
}
static int usbfs_mkdir (struct inode *dir, struct dentry *dentry, int mode)
{
int res;
mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
res = usbfs_mknod (dir, dentry, mode, 0);
if (!res)
inc_nlink(dir);
return res;
}
static int usbfs_create (struct inode *dir, struct dentry *dentry, int mode)
{
mode = (mode & S_IALLUGO) | S_IFREG;
return usbfs_mknod (dir, dentry, mode, 0);
}
static inline int usbfs_positive (struct dentry *dentry)
{
return dentry->d_inode && !d_unhashed(dentry);
}
static int usbfs_empty (struct dentry *dentry)
{
struct list_head *list;
spin_lock(&dcache_lock);
list_for_each(list, &dentry->d_subdirs) {
struct dentry *de = list_entry(list, struct dentry, d_u.d_child);
if (usbfs_positive(de)) {
spin_unlock(&dcache_lock);
return 0;
}
}
spin_unlock(&dcache_lock);
return 1;
}
static int usbfs_unlink (struct inode *dir, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
mutex_lock(&inode->i_mutex);
drop_nlink(dentry->d_inode);
dput(dentry);
mutex_unlock(&inode->i_mutex);
d_delete(dentry);
return 0;
}
static int usbfs_rmdir(struct inode *dir, struct dentry *dentry)
{
int error = -ENOTEMPTY;
struct inode * inode = dentry->d_inode;
mutex_lock(&inode->i_mutex);
dentry_unhash(dentry);
if (usbfs_empty(dentry)) {
dont_mount(dentry);
drop_nlink(dentry->d_inode);
drop_nlink(dentry->d_inode);
dput(dentry);
inode->i_flags |= S_DEAD;
drop_nlink(dir);
error = 0;
}
mutex_unlock(&inode->i_mutex);
if (!error)
d_delete(dentry);
dput(dentry);
return error;
}
/* default file operations */
static ssize_t default_read_file (struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
return 0;
}
static ssize_t default_write_file (struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
return count;
}
static loff_t default_file_lseek (struct file *file, loff_t offset, int orig)
{
loff_t retval = -EINVAL;
mutex_lock(&file->f_path.dentry->d_inode->i_mutex);
switch(orig) {
case 0:
if (offset > 0) {
file->f_pos = offset;
retval = file->f_pos;
}
break;
case 1:
if ((offset + file->f_pos) > 0) {
file->f_pos += offset;
retval = file->f_pos;
}
break;
default:
break;
}
mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
return retval;
}
static int default_open (struct inode *inode, struct file *file)
{
if (inode->i_private)
file->private_data = inode->i_private;
return 0;
}
static const struct file_operations default_file_operations = {
.read = default_read_file,
.write = default_write_file,
.open = default_open,
.llseek = default_file_lseek,
};
static const struct super_operations usbfs_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
.remount_fs = remount,
.show_options = usbfs_show_options,
};
static int usbfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode;
struct dentry *root;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = USBDEVICE_SUPER_MAGIC;
sb->s_op = &usbfs_ops;
sb->s_time_gran = 1;
inode = usbfs_get_inode(sb, S_IFDIR | 0755, 0);
if (!inode) {
dbg("%s: could not get inode!",__func__);
return -ENOMEM;
}
root = d_alloc_root(inode);
if (!root) {
dbg("%s: could not get root dentry!",__func__);
iput(inode);
return -ENOMEM;
}
sb->s_root = root;
return 0;
}
/*
* fs_create_by_name - create a file, given a name
* @name: name of file
* @mode: type of file
* @parent: dentry of directory to create it in
* @dentry: resulting dentry of file
*
* This function handles both regular files and directories.
*/
static int fs_create_by_name (const char *name, mode_t mode,
struct dentry *parent, struct dentry **dentry)
{
int error = 0;
/* If the parent is not specified, we create it in the root.
* We need the root dentry to do this, which is in the super
* block. A pointer to that is in the struct vfsmount that we
* have around.
*/
if (!parent ) {
if (usbfs_mount && usbfs_mount->mnt_sb) {
parent = usbfs_mount->mnt_sb->s_root;
}
}
if (!parent) {
dbg("Ah! can not find a parent!");
return -EFAULT;
}
*dentry = NULL;
mutex_lock(&parent->d_inode->i_mutex);
*dentry = lookup_one_len(name, parent, strlen(name));
if (!IS_ERR(*dentry)) {
if ((mode & S_IFMT) == S_IFDIR)
error = usbfs_mkdir (parent->d_inode, *dentry, mode);
else
error = usbfs_create (parent->d_inode, *dentry, mode);
} else
error = PTR_ERR(*dentry);
mutex_unlock(&parent->d_inode->i_mutex);
return error;
}
static struct dentry *fs_create_file (const char *name, mode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops,
uid_t uid, gid_t gid)
{
struct dentry *dentry;
int error;
dbg("creating file '%s'",name);
error = fs_create_by_name (name, mode, parent, &dentry);
if (error) {
dentry = NULL;
} else {
if (dentry->d_inode) {
if (data)
dentry->d_inode->i_private = data;
if (fops)
dentry->d_inode->i_fop = fops;
dentry->d_inode->i_uid = uid;
dentry->d_inode->i_gid = gid;
}
}
return dentry;
}
static void fs_remove_file (struct dentry *dentry)
{
struct dentry *parent = dentry->d_parent;
if (!parent || !parent->d_inode)
return;
mutex_lock_nested(&parent->d_inode->i_mutex, I_MUTEX_PARENT);
if (usbfs_positive(dentry)) {
if (dentry->d_inode) {
if (S_ISDIR(dentry->d_inode->i_mode))
usbfs_rmdir(parent->d_inode, dentry);
else
usbfs_unlink(parent->d_inode, dentry);
dput(dentry);
}
}
mutex_unlock(&parent->d_inode->i_mutex);
}
/* --------------------------------------------------------------------- */
static int usb_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, usbfs_fill_super, mnt);
}
static struct file_system_type usb_fs_type = {
.owner = THIS_MODULE,
.name = "usbfs",
.get_sb = usb_get_sb,
.kill_sb = kill_litter_super,
};
/* --------------------------------------------------------------------- */
static int create_special_files (void)
{
struct dentry *parent;
int retval;
/* the simple_pin_fs calls will call remount with no options
* without this flag that would overwrite the real mount options (if any)
*/
ignore_mount = 1;
/* create the devices special file */
retval = simple_pin_fs(&usb_fs_type, &usbfs_mount, &usbfs_mount_count);
if (retval) {
printk(KERN_ERR "Unable to get usbfs mount\n");
goto exit;
}
ignore_mount = 0;
parent = usbfs_mount->mnt_sb->s_root;
devices_usbfs_dentry = fs_create_file ("devices",
listmode | S_IFREG, parent,
NULL, &usbfs_devices_fops,
listuid, listgid);
if (devices_usbfs_dentry == NULL) {
printk(KERN_ERR "Unable to create devices usbfs file\n");
retval = -ENODEV;
goto error_clean_mounts;
}
goto exit;
error_clean_mounts:
simple_release_fs(&usbfs_mount, &usbfs_mount_count);
exit:
return retval;
}
static void remove_special_files (void)
{
if (devices_usbfs_dentry)
fs_remove_file (devices_usbfs_dentry);
devices_usbfs_dentry = NULL;
simple_release_fs(&usbfs_mount, &usbfs_mount_count);
}
void usbfs_update_special (void)
{
struct inode *inode;
if (devices_usbfs_dentry) {
inode = devices_usbfs_dentry->d_inode;
if (inode)
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}
}
static void usbfs_add_bus(struct usb_bus *bus)
{
struct dentry *parent;
char name[8];
int retval;
/* create the special files if this is the first bus added */
if (num_buses == 0) {
retval = create_special_files();
if (retval)
return;
}
++num_buses;
sprintf (name, "%03d", bus->busnum);
parent = usbfs_mount->mnt_sb->s_root;
bus->usbfs_dentry = fs_create_file (name, busmode | S_IFDIR, parent,
bus, NULL, busuid, busgid);
if (bus->usbfs_dentry == NULL) {
printk(KERN_ERR "Error creating usbfs bus entry\n");
return;
}
}
static void usbfs_remove_bus(struct usb_bus *bus)
{
if (bus->usbfs_dentry) {
fs_remove_file (bus->usbfs_dentry);
bus->usbfs_dentry = NULL;
}
--num_buses;
if (num_buses <= 0) {
remove_special_files();
num_buses = 0;
}
}
static void usbfs_add_device(struct usb_device *dev)
{
char name[8];
int i;
int i_size;
sprintf (name, "%03d", dev->devnum);
dev->usbfs_dentry = fs_create_file (name, devmode | S_IFREG,
dev->bus->usbfs_dentry, dev,
&usbdev_file_operations,
devuid, devgid);
if (dev->usbfs_dentry == NULL) {
printk(KERN_ERR "Error creating usbfs device entry\n");
return;
}
/* Set the size of the device's file to be
* equal to the size of the device descriptors. */
i_size = sizeof (struct usb_device_descriptor);
for (i = 0; i < dev->descriptor.bNumConfigurations; ++i) {
struct usb_config_descriptor *config =
(struct usb_config_descriptor *)dev->rawdescriptors[i];
i_size += le16_to_cpu(config->wTotalLength);
}
if (dev->usbfs_dentry->d_inode)
dev->usbfs_dentry->d_inode->i_size = i_size;
}
static void usbfs_remove_device(struct usb_device *dev)
{
if (dev->usbfs_dentry) {
fs_remove_file (dev->usbfs_dentry);
dev->usbfs_dentry = NULL;
}
}
static int usbfs_notify(struct notifier_block *self, unsigned long action, void *dev)
{
switch (action) {
case USB_DEVICE_ADD:
usbfs_add_device(dev);
break;
case USB_DEVICE_REMOVE:
usbfs_remove_device(dev);
break;
case USB_BUS_ADD:
usbfs_add_bus(dev);
break;
case USB_BUS_REMOVE:
usbfs_remove_bus(dev);
}
usbfs_update_special();
usbfs_conn_disc_event();
return NOTIFY_OK;
}
static struct notifier_block usbfs_nb = {
.notifier_call = usbfs_notify,
};
/* --------------------------------------------------------------------- */
static struct proc_dir_entry *usbdir = NULL;
int __init usbfs_init(void)
{
int retval;
retval = register_filesystem(&usb_fs_type);
if (retval)
return retval;
usb_register_notify(&usbfs_nb);
/* create mount point for usbfs */
usbdir = proc_mkdir("bus/usb", NULL);
return 0;
}
void usbfs_cleanup(void)
{
usb_unregister_notify(&usbfs_nb);
unregister_filesystem(&usb_fs_type);
if (usbdir)
remove_proc_entry("bus/usb", NULL);
}
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