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