alistair23-linux/drivers/gpu/drm/drm_auth.c
David Herrmann 32e7b94a3f drm: simplify authentication management
The magic auth tokens we have are a simple map from cyclic IDs to drm_file
objects. Remove all the old bulk of code and replace it with a simple,
direct IDR.

The previous behavior is kept. Especially calling authmagic multiple times
on the same magic results in EINVAL except on the first call. The only
difference in behavior is that we never allocate IDs multiple times as
long as a client has its FD open.

v2:
 - Fix return code of GetMagic()
 - Use non-cyclic IDR allocator
 - fix off-by-one in "magic > INT_MAX" sanity check

v3:
 - drop redundant "magic > INT_MAX" check

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-05-05 09:45:57 +02:00

94 lines
3.1 KiB
C

/*
* 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.
*
* Author Rickard E. (Rik) Faith <faith@valinux.com>
* Author Gareth Hughes <gareth@valinux.com>
*
* 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 <drm/drmP.h>
#include "drm_internal.h"
/**
* drm_getmagic - Get unique magic of a client
* @dev: DRM device to operate on
* @data: ioctl data containing the drm_auth object
* @file_priv: DRM file that performs the operation
*
* This looks up the unique magic of the passed client and returns it. If the
* client did not have a magic assigned, yet, a new one is registered. The magic
* is stored in the passed drm_auth object.
*
* Returns: 0 on success, negative error code on failure.
*/
int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
struct drm_auth *auth = data;
int ret = 0;
mutex_lock(&dev->struct_mutex);
if (!file_priv->magic) {
ret = idr_alloc(&file_priv->master->magic_map, file_priv,
1, 0, GFP_KERNEL);
if (ret >= 0)
file_priv->magic = ret;
}
auth->magic = file_priv->magic;
mutex_unlock(&dev->struct_mutex);
DRM_DEBUG("%u\n", auth->magic);
return ret < 0 ? ret : 0;
}
/**
* drm_authmagic - Authenticate client with a magic
* @dev: DRM device to operate on
* @data: ioctl data containing the drm_auth object
* @file_priv: DRM file that performs the operation
*
* This looks up a DRM client by the passed magic and authenticates it.
*
* Returns: 0 on success, negative error code on failure.
*/
int drm_authmagic(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_auth *auth = data;
struct drm_file *file;
DRM_DEBUG("%u\n", auth->magic);
mutex_lock(&dev->struct_mutex);
file = idr_find(&file_priv->master->magic_map, auth->magic);
if (file) {
file->authenticated = 1;
idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
}
mutex_unlock(&dev->struct_mutex);
return file ? 0 : -EINVAL;
}