1/*-
2 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
3 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the next
14 * paragraph) shall be included in all copies or substantial portions of the
15 * Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 * OTHER DEALINGS IN THE SOFTWARE.
24 *
25 * Authors:
26 *    Rickard E. (Rik) Faith <faith@valinux.com>
27 *    Gareth Hughes <gareth@valinux.com>
28 *
29 */
30
31/** @file drm_auth.c
32 * Implementation of the get/authmagic ioctls implementing the authentication
33 * scheme between the master and clients.
34 */
35
36#include "drmP.h"
37
38static int drm_hash_magic(drm_magic_t magic)
39{
40	return magic & (DRM_HASH_SIZE-1);
41}
42
43/**
44 * Returns the file private associated with the given magic number.
45 */
46static struct drm_file *drm_find_file(struct drm_device *dev, drm_magic_t magic)
47{
48	drm_magic_entry_t *pt;
49	int hash = drm_hash_magic(magic);
50
51	DRM_SPINLOCK_ASSERT(&dev->dev_lock);
52
53	for (pt = dev->magiclist[hash].head; pt; pt = pt->next) {
54		if (pt->magic == magic) {
55			return pt->priv;
56		}
57	}
58
59	return NULL;
60}
61
62/**
63 * Inserts the given magic number into the hash table of used magic number
64 * lists.
65 */
66static int drm_add_magic(struct drm_device *dev, struct drm_file *priv,
67			 drm_magic_t magic)
68{
69	int		  hash;
70	drm_magic_entry_t *entry;
71
72	DRM_DEBUG("%d\n", magic);
73
74	DRM_SPINLOCK_ASSERT(&dev->dev_lock);
75
76	hash = drm_hash_magic(magic);
77	entry = malloc(sizeof(*entry), DRM_MEM_MAGIC, M_ZERO | M_NOWAIT);
78	if (!entry)
79		return ENOMEM;
80	entry->magic = magic;
81	entry->priv  = priv;
82	entry->next  = NULL;
83
84	if (dev->magiclist[hash].tail) {
85		dev->magiclist[hash].tail->next = entry;
86		dev->magiclist[hash].tail	= entry;
87	} else {
88		dev->magiclist[hash].head	= entry;
89		dev->magiclist[hash].tail	= entry;
90	}
91
92	return 0;
93}
94
95/**
96 * Removes the given magic number from the hash table of used magic number
97 * lists.
98 */
99static int drm_remove_magic(struct drm_device *dev, drm_magic_t magic)
100{
101	drm_magic_entry_t *prev = NULL;
102	drm_magic_entry_t *pt;
103	int		  hash;
104
105	DRM_SPINLOCK_ASSERT(&dev->dev_lock);
106
107	DRM_DEBUG("%d\n", magic);
108	hash = drm_hash_magic(magic);
109
110	for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) {
111		if (pt->magic == magic) {
112			if (dev->magiclist[hash].head == pt) {
113				dev->magiclist[hash].head = pt->next;
114			}
115			if (dev->magiclist[hash].tail == pt) {
116				dev->magiclist[hash].tail = prev;
117			}
118			if (prev) {
119				prev->next = pt->next;
120			}
121			free(pt, DRM_MEM_MAGIC);
122			return 0;
123		}
124	}
125
126	return EINVAL;
127}
128
129/**
130 * Called by the client, this returns a unique magic number to be authorized
131 * by the master.
132 *
133 * The master may use its own knowledge of the client (such as the X
134 * connection that the magic is passed over) to determine if the magic number
135 * should be authenticated.
136 */
137int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
138{
139	static drm_magic_t sequence = 0;
140	struct drm_auth *auth = data;
141
142	/* Find unique magic */
143	if (file_priv->magic) {
144		auth->magic = file_priv->magic;
145	} else {
146		DRM_LOCK();
147		do {
148			int old = sequence;
149
150			auth->magic = old+1;
151
152			if (!atomic_cmpset_int(&sequence, old, auth->magic))
153				continue;
154		} while (drm_find_file(dev, auth->magic));
155		file_priv->magic = auth->magic;
156		drm_add_magic(dev, file_priv, auth->magic);
157		DRM_UNLOCK();
158	}
159
160	DRM_DEBUG("%u\n", auth->magic);
161
162	return 0;
163}
164
165/**
166 * Marks the client associated with the given magic number as authenticated.
167 */
168int drm_authmagic(struct drm_device *dev, void *data,
169		  struct drm_file *file_priv)
170{
171	struct drm_auth *auth = data;
172	struct drm_file *priv;
173
174	DRM_DEBUG("%u\n", auth->magic);
175
176	DRM_LOCK();
177	priv = drm_find_file(dev, auth->magic);
178	if (priv != NULL) {
179		priv->authenticated = 1;
180		drm_remove_magic(dev, auth->magic);
181		DRM_UNLOCK();
182		return 0;
183	} else {
184		DRM_UNLOCK();
185		return EINVAL;
186	}
187}
188