1 /**
2 * \file drm_auth.c
3 * IOCTLs for authentication
4 *
5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
7 */
8
9 /*
10 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
11 *
12 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a
17 * copy of this software and associated documentation files (the "Software"),
18 * to deal in the Software without restriction, including without limitation
19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20 * and/or sell copies of the Software, and to permit persons to whom the
21 * Software is furnished to do so, subject to the following conditions:
22 *
23 * The above copyright notice and this permission notice (including the next
24 * paragraph) shall be included in all copies or substantial portions of the
25 * Software.
26 *
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33 * OTHER DEALINGS IN THE SOFTWARE.
34 */
35
36 #include "drmP.h"
37
38 /**
39 * Find the file with the given magic number.
40 *
41 * \param dev DRM device.
42 * \param magic magic number.
43 *
44 * Searches in drm_device::magiclist within all files with the same hash key
45 * the one with matching magic number, while holding the drm_device::struct_mutex
46 * lock.
47 */
48 static struct drm_file *drm_find_file(struct drm_device * dev, drm_magic_t magic)
49 {
50 struct drm_file *retval = NULL;
51 struct drm_magic_entry *pt;
52 struct drm_hash_item *hash;
53
54 mutex_lock(&dev->struct_mutex);
55 if (!drm_ht_find_item(&dev->magiclist, (unsigned long)magic, &hash)) {
56 pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
57 retval = pt->priv;
58 }
59 mutex_unlock(&dev->struct_mutex);
60 return retval;
61 }
62
63 /**
64 * Adds a magic number.
65 *
66 * \param dev DRM device.
67 * \param priv file private data.
68 * \param magic magic number.
69 *
70 * Creates a drm_magic_entry structure and appends to the linked list
71 * associated the magic number hash key in drm_device::magiclist, while holding
72 * the drm_device::struct_mutex lock.
73 */
74 static int drm_add_magic(struct drm_device * dev, struct drm_file * priv,
75 drm_magic_t magic)
76 {
77 struct drm_magic_entry *entry;
78
79 DRM_DEBUG("%d\n", magic);
80
81 entry = drm_alloc(sizeof(*entry), DRM_MEM_MAGIC);
82 if (!entry)
83 return -ENOMEM;
84 memset(entry, 0, sizeof(*entry));
85 entry->priv = priv;
86
87 entry->hash_item.key = (unsigned long)magic;
88 mutex_lock(&dev->struct_mutex);
89 drm_ht_insert_item(&dev->magiclist, &entry->hash_item);
90 list_add_tail(&entry->head, &dev->magicfree);
91 mutex_unlock(&dev->struct_mutex);
92
93 return 0;
94 }
95
96 /**
97 * Remove a magic number.
98 *
99 * \param dev DRM device.
100 * \param magic magic number.
101 *
102 * Searches and unlinks the entry in drm_device::magiclist with the magic
103 * number hash key, while holding the drm_device::struct_mutex lock.
104 */
105 static int drm_remove_magic(struct drm_device * dev, drm_magic_t magic)
106 {
107 struct drm_magic_entry *pt;
108 struct drm_hash_item *hash;
109
110 DRM_DEBUG("%d\n", magic);
111
112 mutex_lock(&dev->struct_mutex);
113 if (drm_ht_find_item(&dev->magiclist, (unsigned long)magic, &hash)) {
114 mutex_unlock(&dev->struct_mutex);
115 return -EINVAL;
116 }
117 pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
118 drm_ht_remove_item(&dev->magiclist, hash);
119 list_del(&pt->head);
120 mutex_unlock(&dev->struct_mutex);
121
122 drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC);
123
124 return 0;
125 }
126
127 /**
128 * Get a unique magic number (ioctl).
129 *
130 * \param inode device inode.
131 * \param file_priv DRM file private.
132 * \param cmd command.
133 * \param arg pointer to a resulting drm_auth structure.
134 * \return zero on success, or a negative number on failure.
135 *
136 * If there is a magic number in drm_file::magic then use it, otherwise
137 * searches an unique non-zero magic number and add it associating it with \p
138 * file_priv.
139 */
140 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
141 {
142 static drm_magic_t sequence = 0;
143 static DEFINE_SPINLOCK(lock);
144 struct drm_auth *auth = data;
145
146 /* Find unique magic */
147 if (file_priv->magic) {
148 auth->magic = file_priv->magic;
149 } else {
150 do {
151 spin_lock(&lock);
152 if (!sequence)
153 ++sequence; /* reserve 0 */
154 auth->magic = sequence++;
155 spin_unlock(&lock);
156 } while (drm_find_file(dev, auth->magic));
157 file_priv->magic = auth->magic;
158 drm_add_magic(dev, file_priv, auth->magic);
159 }
160
161 DRM_DEBUG("%u\n", auth->magic);
162
163 return 0;
164 }
165
166 /**
167 * Authenticate with a magic.
168 *
169 * \param inode device inode.
170 * \param file_priv DRM file private.
171 * \param cmd command.
172 * \param arg pointer to a drm_auth structure.
173 * \return zero if authentication successed, or a negative number otherwise.
174 *
175 * Checks if \p file_priv is associated with the magic number passed in \arg.
176 */
177 int drm_authmagic(struct drm_device *dev, void *data,
178 struct drm_file *file_priv)
179 {
180 struct drm_auth *auth = data;
181 struct drm_file *file;
182
183 DRM_DEBUG("%u\n", auth->magic);
184 if ((file = drm_find_file(dev, auth->magic))) {
185 file->authenticated = 1;
186 drm_remove_magic(dev, auth->magic);
187 return 0;
188 }
189 return -EINVAL;
190 }
191
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