inode.c

linux-2.6.15.6

/*****************************************************************************/

/*
 *	inode.c  --  Inode/Dentry functions for the USB device file system.
 *
 *	Copyright (C) 2000 Thomas Sailer ([e-mail])
 *	Copyright (C) 2001,2002,2004 Greg Kroah-Hartman ([e-mail])
 *
 *	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/config.h>
#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/smp_lock.h>
#include <linux/parser.h>
#include <linux/notifier.h>
#include <asm/byteorder.h>
#include "usb.h"
#include "hcd.h"

static struct super_operations usbfs_ops;
static 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 = S_IWUSR | S_IRUGO;
static umode_t busmode = S_IXUGO | S_IRUGO;
static umode_t listmode = S_IRUGO;

enum {
	Opt_devuid, Opt_devgid, Opt_devmode,
	Opt_busuid, Opt_busgid, Opt_busmode,
	Opt_listuid, Opt_listgid, Opt_listmode,
	Opt_err,
};

static 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 = S_IWUSR | S_IRUGO;
	busmode = S_IXUGO | S_IRUGO;
	listmode = S_IRUGO;

	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:
			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;

	down(&bus->d_inode->i_sem);

	list_for_each_entry(dev, &bus->d_subdirs, d_child)
		if (dev->d_inode)
			update_dev(dev);

	up(&bus->d_inode->i_sem);
}

static void update_sb(struct super_block *sb)
{
	struct dentry *root = sb->s_root;
	struct dentry *bus = NULL;

	if (!root)
		return;

	down(&root->d_inode->i_sem);

	list_for_each_entry(bus, &root->d_subdirs, 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:
				warn("Unknown node %s mode %x found on remount!\n",bus->d_name.name,bus->d_inode->i_mode);
				break;
			}
		}
	}

	up(&root->d_inode->i_sem);
}

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)) {
		warn("usbfs: mount parameter error:");
		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_mode = mode;
		inode->i_uid = current->fsuid;
		inode->i_gid = current->fsgid;
		inode->i_blksize = PAGE_CACHE_SIZE;
		inode->i_blocks = 0;
		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) */
			inode->i_nlink++;
			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)
		dir->i_nlink++;
	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_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;
	down(&inode->i_sem);
	dentry->d_inode->i_nlink--;
	dput(dentry);
	up(&inode->i_sem);
	d_delete(dentry);
	return 0;
}

static int usbfs_rmdir(struct inode *dir, struct dentry *dentry)
{
	int error = -ENOTEMPTY;
	struct inode * inode = dentry->d_inode;

	down(&inode->i_sem);
	dentry_unhash(dentry);
	if (usbfs_empty(dentry)) {
		dentry->d_inode->i_nlink -= 2;
		dput(dentry);
		inode->i_flags |= S_DEAD;
		dir->i_nlink--;
		error = 0;
	}
	up(&inode->i_sem);
	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;