/**
* \file drm_auth.c
* IOCTLs for authentication
*
* \author Rickard E. (Rik) Faith <faith@valinux.com>
* \author Gareth Hughes <gareth@valinux.com>
*/
/*
* Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
*
* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include "drmP.h"
/**
* Generate a hash key from a magic.
*
* \param magic magic.
* \return hash key.
*
* The key is the modulus of the hash table size, #DRM_HASH_SIZE, which must be
* a power of 2.
*/
static int drm_hash_magic(drm_magic_t magic)
{
return magic & (DRM_HASH_SIZE - 1);
}
/**
* Find the file with the given magic number.
*
* \param dev DRM device.
* \param magic magic number.
*
* Searches in drm_device::magiclist within all files with the same hash key
* the one with matching magic number, while holding the drm_device::struct_mutex
* lock.
*/
static drm_file_t *drm_find_file(drm_device_t * dev, drm_magic_t magic)
{
drm_file_t *retval = NULL;
drm_magic_entry_t *pt;
int hash = drm_hash_magic(magic);
mutex_lock(&dev->struct_mutex);
for (pt = dev->magiclist[hash].head; pt; pt = pt->next) {
if (pt->magic == magic) {
retval = pt->priv;
break;
}
}
mutex_unlock(&dev->struct_mutex);
return retval;
}
/**
* Adds a magic number.
*
* \param dev DRM device.
* \param priv file private data.
* \param magic magic number.
*
* Creates a drm_magic_entry structure and appends to the linked list
* associated the magic number hash key in drm_device::magiclist, while holding
* the drm_device::struct_mutex lock.
*/
static int drm_add_magic(drm_device_t * dev, drm_file_t * priv,
drm_magic_t magic)
{
int hash;
drm_magic_entry_t *entry;
DRM_DEBUG("%d\n", magic);
hash = drm_hash_magic(magic);
entry = drm_alloc(sizeof(*entry), DRM_MEM_MAGIC);
if (!entry)
return -ENOMEM;
memset(entry, 0, sizeof(*entry));
entry->magic = magic;
entry->priv = priv;
entry->next = NULL;
mutex_lock(&dev->struct_mutex);
if (dev->magiclist[hash].tail) {
dev->magiclist[hash].tail->next = entry;
dev->magiclist[hash].tail = entry;
} else {
dev->magiclist[hash].head = entry;
dev->magiclist[hash].tail = entry;
}
mutex_unlock(&dev->struct_mutex);
return 0;
}
/**
* Remove a magic number.
*
* \param dev DRM device.
* \param magic magic number.
*
* Searches and unlinks the entry in drm_device::magiclist with the magic
* number hash key, while holding the drm_device::struct_mutex lock.
*/
static int drm_remove_magic(drm_device_t * dev, drm_magic_t magic)
{
drm_magic_entry_t *prev = NULL;
drm_magic_entry_t *pt;
int hash;
DRM_DEBUG("%d\n", magic);
hash = drm_hash_magic(magic);
mutex_lock(&dev->struct_mutex);
for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) {
if (pt->magic == magic) {
if (dev->magiclist[hash].head == pt) {
dev->magiclist[hash].head = pt->next;
}
if (dev->magiclist[hash].tail == pt) {
dev->magiclist[hash].tail = prev;
}
if (prev) {
prev->next = pt->next;
}
mutex_unlock(&dev->struct_mutex);
return 0;
}
}
mutex_unlock(&dev->struct_mutex);
drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC);
return -EINVAL;
}
/**
* Get a unique magic number (ioctl).
*
* \param inode device inode.
* \param filp file pointer.
* \param cmd command.
* \param arg pointer to a resulting drm_auth structure.
* \return zero on success, or a negative number on failure.
*
* If there is a magic number in drm_file::magic then use it, otherwise
* searches an unique non-zero magic number and add it associating it with \p
* filp.
*/
int drm_getmagic(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
static drm_magic_t sequence = 0;
static DEFINE_SPINLOCK(lock);
drm_file_t *priv = filp->private_data;
drm_device_t *dev = priv->head->dev;
drm_auth_t auth;
/* Find unique magic */
if (priv->magic) {
auth.magic = priv->magic;
} else {
do {
spin_lock(&lock);
if (!sequence)
++sequence; /* reserve 0 */
auth.magic = sequence++;
spin_unlock(&lock);
} while (drm_find_file(dev, auth.magic));
priv->magic = auth.magic;
drm_add_magic(dev, priv, auth.magic);
}
DRM_DEBUG("%u\n", auth.magic);
if (copy_to_user((drm_auth_t __user *) arg, &auth, sizeof(auth)))
return -EFAULT;
return 0;
}
/**
* Authenticate with a magic.
*
* \param inode device inode.
* \param filp file pointer.
* \param cmd command.
* \param arg pointer to a drm_auth structure.
* \return zero if authentication successed, or a negative number otherwise.
*
* Checks if \p filp is associated with the magic number passed in \arg.
*/
int drm_authmagic(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
drm_file_t *priv = filp->private_data;
drm_device_t *dev = priv->head->dev;
drm_auth_t auth;
drm_file_t *file;
if (copy_from_user(&auth, (drm_auth_t __user *) arg, sizeof(auth)))
return -EFAULT;
DRM_DEBUG("%u\n", auth.magic);
if ((file = drm_find_file(dev, auth.magic))) {
file->authenticated = 1;
drm_remove_magic(dev, auth.magic);
return 0;
}
return -EINVAL;
}
