tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 * 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 */
47static 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 */
62static 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 */
90static int drm_add_magic(drm_device_t * dev, drm_file_t * priv,
91 drm_magic_t magic)
92{
93 int hash;
94 drm_magic_entry_t *entry;
95
96 DRM_DEBUG("%d\n", magic);
97
98 hash = drm_hash_magic(magic);
99 entry = drm_alloc(sizeof(*entry), DRM_MEM_MAGIC);
100 if (!entry)
101 return -ENOMEM;
102 memset(entry, 0, sizeof(*entry));
103 entry->magic = magic;
104 entry->priv = priv;
105 entry->next = NULL;
106
107 down(&dev->struct_sem);
108 if (dev->magiclist[hash].tail) {
109 dev->magiclist[hash].tail->next = entry;
110 dev->magiclist[hash].tail = entry;
111 } else {
112 dev->magiclist[hash].head = entry;
113 dev->magiclist[hash].tail = entry;
114 }
115 up(&dev->struct_sem);
116
117 return 0;
118}
119
120/**
121 * Remove a magic number.
122 *
123 * \param dev DRM device.
124 * \param magic magic number.
125 *
126 * Searches and unlinks the entry in drm_device::magiclist with the magic
127 * number hash key, while holding the drm_device::struct_sem lock.
128 */
129static int drm_remove_magic(drm_device_t * dev, drm_magic_t magic)
130{
131 drm_magic_entry_t *prev = NULL;
132 drm_magic_entry_t *pt;
133 int hash;
134
135 DRM_DEBUG("%d\n", magic);
136 hash = drm_hash_magic(magic);
137
138 down(&dev->struct_sem);
139 for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) {
140 if (pt->magic == magic) {
141 if (dev->magiclist[hash].head == pt) {
142 dev->magiclist[hash].head = pt->next;
143 }
144 if (dev->magiclist[hash].tail == pt) {
145 dev->magiclist[hash].tail = prev;
146 }
147 if (prev) {
148 prev->next = pt->next;
149 }
150 up(&dev->struct_sem);
151 return 0;
152 }
153 }
154 up(&dev->struct_sem);
155
156 drm_free(pt, sizeof(*pt), DRM_MEM_MAGIC);
157
158 return -EINVAL;
159}
160
161/**
162 * Get a unique magic number (ioctl).
163 *
164 * \param inode device inode.
165 * \param filp file pointer.
166 * \param cmd command.
167 * \param arg pointer to a resulting drm_auth structure.
168 * \return zero on success, or a negative number on failure.
169 *
170 * If there is a magic number in drm_file::magic then use it, otherwise
171 * searches an unique non-zero magic number and add it associating it with \p
172 * filp.
173 */
174int drm_getmagic(struct inode *inode, struct file *filp,
175 unsigned int cmd, unsigned long arg)
176{
177 static drm_magic_t sequence = 0;
178 static DEFINE_SPINLOCK(lock);
179 drm_file_t *priv = filp->private_data;
180 drm_device_t *dev = priv->head->dev;
181 drm_auth_t auth;
182
183 /* Find unique magic */
184 if (priv->magic) {
185 auth.magic = priv->magic;
186 } else {
187 do {
188 spin_lock(&lock);
189 if (!sequence)
190 ++sequence; /* reserve 0 */
191 auth.magic = sequence++;
192 spin_unlock(&lock);
193 } while (drm_find_file(dev, auth.magic));
194 priv->magic = auth.magic;
195 drm_add_magic(dev, priv, auth.magic);
196 }
197
198 DRM_DEBUG("%u\n", auth.magic);
199 if (copy_to_user((drm_auth_t __user *) arg, &auth, sizeof(auth)))
200 return -EFAULT;
201 return 0;
202}
203
204/**
205 * Authenticate with a magic.
206 *
207 * \param inode device inode.
208 * \param filp file pointer.
209 * \param cmd command.
210 * \param arg pointer to a drm_auth structure.
211 * \return zero if authentication successed, or a negative number otherwise.
212 *
213 * Checks if \p filp is associated with the magic number passed in \arg.
214 */
215int drm_authmagic(struct inode *inode, struct file *filp,
216 unsigned int cmd, unsigned long arg)
217{
218 drm_file_t *priv = filp->private_data;
219 drm_device_t *dev = priv->head->dev;
220 drm_auth_t auth;
221 drm_file_t *file;
222
223 if (copy_from_user(&auth, (drm_auth_t __user *) arg, sizeof(auth)))
224 return -EFAULT;
225 DRM_DEBUG("%u\n", auth.magic);
226 if ((file = drm_find_file(dev, auth.magic))) {
227 file->authenticated = 1;
228 drm_remove_magic(dev, auth.magic);
229 return 0;
230 }
231 return -EINVAL;
232}