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1da177e4 LT |
1 | /** |
2 | * \file drm_auth.h | |
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 | * Generate a hash key from a magic. | |
40 | * | |
41 | * \param magic magic. | |
42 | * \return hash key. | |
43 | * | |
44 | * The key is the modulus of the hash table size, #DRM_HASH_SIZE, which must be | |
45 | * a power of 2. | |
46 | */ | |
47 | static int drm_hash_magic(drm_magic_t magic) | |
48 | { | |
49 | return magic & (DRM_HASH_SIZE-1); | |
50 | } | |
51 | ||
52 | /** | |
53 | * Find the file with the given magic number. | |
54 | * | |
55 | * \param dev DRM device. | |
56 | * \param magic magic number. | |
57 | * | |
58 | * Searches in drm_device::magiclist within all files with the same hash key | |
59 | * the one with matching magic number, while holding the drm_device::struct_sem | |
60 | * lock. | |
61 | */ | |
62 | static drm_file_t *drm_find_file(drm_device_t *dev, drm_magic_t magic) | |
63 | { | |
64 | drm_file_t *retval = NULL; | |
65 | drm_magic_entry_t *pt; | |
66 | int hash = drm_hash_magic(magic); | |
67 | ||
68 | down(&dev->struct_sem); | |
69 | for (pt = dev->magiclist[hash].head; pt; pt = pt->next) { | |
70 | if (pt->magic == magic) { | |
71 | retval = pt->priv; | |
72 | break; | |
73 | } | |
74 | } | |
75 | up(&dev->struct_sem); | |
76 | return retval; | |
77 | } | |
78 | ||
79 | /** | |
80 | * Adds a magic number. | |
81 | * | |
82 | * \param dev DRM device. | |
83 | * \param priv file private data. | |
84 | * \param magic magic number. | |
85 | * | |
86 | * Creates a drm_magic_entry structure and appends to the linked list | |
87 | * associated the magic number hash key in drm_device::magiclist, while holding | |
88 | * the drm_device::struct_sem lock. | |
89 | */ | |
90 | int drm_add_magic(drm_device_t *dev, drm_file_t *priv, drm_magic_t magic) | |
91 | { | |
92 | int hash; | |
93 | drm_magic_entry_t *entry; | |
94 | ||
95 | DRM_DEBUG("%d\n", magic); | |
96 | ||
97 | hash = drm_hash_magic(magic); | |
98 | entry = drm_alloc(sizeof(*entry), DRM_MEM_MAGIC); | |
99 | if (!entry) return -ENOMEM; | |
100 | memset(entry, 0, sizeof(*entry)); | |
101 | entry->magic = magic; | |
102 | entry->priv = priv; | |
103 | entry->next = NULL; | |
104 | ||
105 | down(&dev->struct_sem); | |
106 | if (dev->magiclist[hash].tail) { | |
107 | dev->magiclist[hash].tail->next = entry; | |
108 | dev->magiclist[hash].tail = entry; | |
109 | } else { | |
110 | dev->magiclist[hash].head = entry; | |
111 | dev->magiclist[hash].tail = entry; | |
112 | } | |
113 | up(&dev->struct_sem); | |
114 | ||
115 | return 0; | |
116 | } | |
117 | ||
118 | /** | |
119 | * Remove a magic number. | |
120 | * | |
121 | * \param dev DRM device. | |
122 | * \param magic magic number. | |
123 | * | |
124 | * Searches and unlinks the entry in drm_device::magiclist with the magic | |
125 | * number hash key, while holding the drm_device::struct_sem lock. | |
126 | */ | |
127 | int drm_remove_magic(drm_device_t *dev, drm_magic_t magic) | |
128 | { | |
129 | drm_magic_entry_t *prev = NULL; | |
130 | drm_magic_entry_t *pt; | |
131 | int hash; | |
132 | ||
133 | ||
134 | DRM_DEBUG("%d\n", magic); | |
135 | hash = drm_hash_magic(magic); | |
136 | ||
137 | down(&dev->struct_sem); | |
138 | for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) { | |
139 | if (pt->magic == magic) { | |
140 | if (dev->magiclist[hash].head == pt) { | |
141 | dev->magiclist[hash].head = pt->next; | |
142 | } | |
143 | if (dev->magiclist[hash].tail == pt) { | |
144 | dev->magiclist[hash].tail = prev; | |
145 | } | |
146 | if (prev) { | |
147 | prev->next = pt->next; | |
148 | } | |
149 | up(&dev->struct_sem); | |
150 | return 0; | |
151 | } | |
152 | } | |
153 | up(&dev->struct_sem); | |
154 | ||
155 | drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC); | |
156 | ||
157 | return -EINVAL; | |
158 | } | |
159 | ||
160 | /** | |
161 | * Get a unique magic number (ioctl). | |
162 | * | |
163 | * \param inode device inode. | |
164 | * \param filp file pointer. | |
165 | * \param cmd command. | |
166 | * \param arg pointer to a resulting drm_auth structure. | |
167 | * \return zero on success, or a negative number on failure. | |
168 | * | |
169 | * If there is a magic number in drm_file::magic then use it, otherwise | |
170 | * searches an unique non-zero magic number and add it associating it with \p | |
171 | * filp. | |
172 | */ | |
173 | int drm_getmagic(struct inode *inode, struct file *filp, | |
174 | unsigned int cmd, unsigned long arg) | |
175 | { | |
176 | static drm_magic_t sequence = 0; | |
177 | static DEFINE_SPINLOCK(lock); | |
178 | drm_file_t *priv = filp->private_data; | |
179 | drm_device_t *dev = priv->head->dev; | |
180 | drm_auth_t auth; | |
181 | ||
182 | /* Find unique magic */ | |
183 | if (priv->magic) { | |
184 | auth.magic = priv->magic; | |
185 | } else { | |
186 | do { | |
187 | spin_lock(&lock); | |
188 | if (!sequence) ++sequence; /* reserve 0 */ | |
189 | auth.magic = sequence++; | |
190 | spin_unlock(&lock); | |
191 | } while (drm_find_file(dev, auth.magic)); | |
192 | priv->magic = auth.magic; | |
193 | drm_add_magic(dev, priv, auth.magic); | |
194 | } | |
195 | ||
196 | DRM_DEBUG("%u\n", auth.magic); | |
197 | if (copy_to_user((drm_auth_t __user *)arg, &auth, sizeof(auth))) | |
198 | return -EFAULT; | |
199 | return 0; | |
200 | } | |
201 | ||
202 | /** | |
203 | * Authenticate with a magic. | |
204 | * | |
205 | * \param inode device inode. | |
206 | * \param filp file pointer. | |
207 | * \param cmd command. | |
208 | * \param arg pointer to a drm_auth structure. | |
209 | * \return zero if authentication successed, or a negative number otherwise. | |
210 | * | |
211 | * Checks if \p filp is associated with the magic number passed in \arg. | |
212 | */ | |
213 | int drm_authmagic(struct inode *inode, struct file *filp, | |
214 | unsigned int cmd, unsigned long arg) | |
215 | { | |
216 | drm_file_t *priv = filp->private_data; | |
217 | drm_device_t *dev = priv->head->dev; | |
218 | drm_auth_t auth; | |
219 | drm_file_t *file; | |
220 | ||
221 | if (copy_from_user(&auth, (drm_auth_t __user *)arg, sizeof(auth))) | |
222 | return -EFAULT; | |
223 | DRM_DEBUG("%u\n", auth.magic); | |
224 | if ((file = drm_find_file(dev, auth.magic))) { | |
225 | file->authenticated = 1; | |
226 | drm_remove_magic(dev, auth.magic); | |
227 | return 0; | |
228 | } | |
229 | return -EINVAL; | |
230 | } |