Root/drivers/gpu/drm/drm_auth.c

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 */
48static struct drm_file *drm_find_file(struct drm_master *master, drm_magic_t magic)
49{
50    struct drm_file *retval = NULL;
51    struct drm_magic_entry *pt;
52    struct drm_hash_item *hash;
53    struct drm_device *dev = master->minor->dev;
54
55    mutex_lock(&dev->struct_mutex);
56    if (!drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) {
57        pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
58        retval = pt->priv;
59    }
60    mutex_unlock(&dev->struct_mutex);
61    return retval;
62}
63
64/**
65 * Adds a magic number.
66 *
67 * \param dev DRM device.
68 * \param priv file private data.
69 * \param magic magic number.
70 *
71 * Creates a drm_magic_entry structure and appends to the linked list
72 * associated the magic number hash key in drm_device::magiclist, while holding
73 * the drm_device::struct_mutex lock.
74 */
75static int drm_add_magic(struct drm_master *master, struct drm_file *priv,
76             drm_magic_t magic)
77{
78    struct drm_magic_entry *entry;
79    struct drm_device *dev = master->minor->dev;
80    DRM_DEBUG("%d\n", magic);
81
82    entry = kzalloc(sizeof(*entry), GFP_KERNEL);
83    if (!entry)
84        return -ENOMEM;
85    entry->priv = priv;
86    entry->hash_item.key = (unsigned long)magic;
87    mutex_lock(&dev->struct_mutex);
88    drm_ht_insert_item(&master->magiclist, &entry->hash_item);
89    list_add_tail(&entry->head, &master->magicfree);
90    mutex_unlock(&dev->struct_mutex);
91
92    return 0;
93}
94
95/**
96 * Remove a magic number.
97 *
98 * \param dev DRM device.
99 * \param magic magic number.
100 *
101 * Searches and unlinks the entry in drm_device::magiclist with the magic
102 * number hash key, while holding the drm_device::struct_mutex lock.
103 */
104int drm_remove_magic(struct drm_master *master, drm_magic_t magic)
105{
106    struct drm_magic_entry *pt;
107    struct drm_hash_item *hash;
108    struct drm_device *dev = master->minor->dev;
109
110    DRM_DEBUG("%d\n", magic);
111
112    mutex_lock(&dev->struct_mutex);
113    if (drm_ht_find_item(&master->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(&master->magiclist, hash);
119    list_del(&pt->head);
120    mutex_unlock(&dev->struct_mutex);
121
122    kfree(pt);
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 * This ioctl needs protection by the drm_global_mutex, which protects
140 * struct drm_file::magic and struct drm_magic_entry::priv.
141 */
142int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
143{
144    static drm_magic_t sequence = 0;
145    static DEFINE_SPINLOCK(lock);
146    struct drm_auth *auth = data;
147
148    /* Find unique magic */
149    if (file_priv->magic) {
150        auth->magic = file_priv->magic;
151    } else {
152        do {
153            spin_lock(&lock);
154            if (!sequence)
155                ++sequence; /* reserve 0 */
156            auth->magic = sequence++;
157            spin_unlock(&lock);
158        } while (drm_find_file(file_priv->master, auth->magic));
159        file_priv->magic = auth->magic;
160        drm_add_magic(file_priv->master, file_priv, auth->magic);
161    }
162
163    DRM_DEBUG("%u\n", auth->magic);
164
165    return 0;
166}
167
168/**
169 * Authenticate with a magic.
170 *
171 * \param inode device inode.
172 * \param file_priv DRM file private.
173 * \param cmd command.
174 * \param arg pointer to a drm_auth structure.
175 * \return zero if authentication successed, or a negative number otherwise.
176 *
177 * Checks if \p file_priv is associated with the magic number passed in \arg.
178 * This ioctl needs protection by the drm_global_mutex, which protects
179 * struct drm_file::magic and struct drm_magic_entry::priv.
180 */
181int drm_authmagic(struct drm_device *dev, void *data,
182          struct drm_file *file_priv)
183{
184    struct drm_auth *auth = data;
185    struct drm_file *file;
186
187    DRM_DEBUG("%u\n", auth->magic);
188    if ((file = drm_find_file(file_priv->master, auth->magic))) {
189        file->authenticated = 1;
190        drm_remove_magic(file_priv->master, auth->magic);
191        return 0;
192    }
193    return -EINVAL;
194}
195

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