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 <sys/cdefs.h>
37#include <dev/drm2/drmP.h>
38
39static struct mtx drm_magic_lock;
40
41/**
42 * Find the file with the given magic number.
43 *
44 * \param dev DRM device.
45 * \param magic magic number.
46 *
47 * Searches in drm_device::magiclist within all files with the same hash key
48 * the one with matching magic number, while holding the drm_device::struct_mutex
49 * lock.
50 */
51static struct drm_file *drm_find_file(struct drm_master *master, drm_magic_t magic)
52{
53	struct drm_file *retval = NULL;
54	struct drm_magic_entry *pt;
55	struct drm_hash_item *hash;
56	struct drm_device *dev = master->minor->dev;
57
58	DRM_LOCK(dev);
59	if (!drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) {
60		pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
61		retval = pt->priv;
62	}
63	DRM_UNLOCK(dev);
64	return retval;
65}
66
67/**
68 * Adds a magic number.
69 *
70 * \param dev DRM device.
71 * \param priv file private data.
72 * \param magic magic number.
73 *
74 * Creates a drm_magic_entry structure and appends to the linked list
75 * associated the magic number hash key in drm_device::magiclist, while holding
76 * the drm_device::struct_mutex lock.
77 */
78static int drm_add_magic(struct drm_master *master, struct drm_file *priv,
79			 drm_magic_t magic)
80{
81	struct drm_magic_entry *entry;
82	struct drm_device *dev = master->minor->dev;
83	DRM_DEBUG("%d\n", magic);
84
85	entry = malloc(sizeof(*entry), DRM_MEM_MAGIC, M_ZERO | M_NOWAIT);
86	if (!entry)
87		return -ENOMEM;
88	entry->priv = priv;
89	entry->hash_item.key = (unsigned long)magic;
90	DRM_LOCK(dev);
91	drm_ht_insert_item(&master->magiclist, &entry->hash_item);
92	list_add_tail(&entry->head, &master->magicfree);
93	DRM_UNLOCK(dev);
94
95	return 0;
96}
97
98/**
99 * Remove a magic number.
100 *
101 * \param dev DRM device.
102 * \param magic magic number.
103 *
104 * Searches and unlinks the entry in drm_device::magiclist with the magic
105 * number hash key, while holding the drm_device::struct_mutex lock.
106 */
107int drm_remove_magic(struct drm_master *master, drm_magic_t magic)
108{
109	struct drm_magic_entry *pt;
110	struct drm_hash_item *hash;
111	struct drm_device *dev = master->minor->dev;
112
113	DRM_DEBUG("%d\n", magic);
114
115	DRM_LOCK(dev);
116	if (drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) {
117		DRM_UNLOCK(dev);
118		return -EINVAL;
119	}
120	pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
121	drm_ht_remove_item(&master->magiclist, hash);
122	list_del(&pt->head);
123	DRM_UNLOCK(dev);
124
125	free(pt, DRM_MEM_MAGIC);
126
127	return 0;
128}
129
130/**
131 * Get a unique magic number (ioctl).
132 *
133 * \param inode device inode.
134 * \param file_priv DRM file private.
135 * \param cmd command.
136 * \param arg pointer to a resulting drm_auth structure.
137 * \return zero on success, or a negative number on failure.
138 *
139 * If there is a magic number in drm_file::magic then use it, otherwise
140 * searches an unique non-zero magic number and add it associating it with \p
141 * file_priv.
142 * This ioctl needs protection by the drm_global_mutex, which protects
143 * struct drm_file::magic and struct drm_magic_entry::priv.
144 */
145int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
146{
147	static drm_magic_t sequence = 0;
148	struct drm_auth *auth = data;
149
150	/* Find unique magic */
151	if (file_priv->magic) {
152		auth->magic = file_priv->magic;
153	} else {
154		do {
155			mtx_lock(&drm_magic_lock);
156			if (!sequence)
157				++sequence;	/* reserve 0 */
158			auth->magic = sequence++;
159			mtx_unlock(&drm_magic_lock);
160		} while (drm_find_file(file_priv->master, auth->magic));
161		file_priv->magic = auth->magic;
162		drm_add_magic(file_priv->master, file_priv, auth->magic);
163	}
164
165	DRM_DEBUG("%u\n", auth->magic);
166
167	return 0;
168}
169
170/**
171 * Authenticate with a magic.
172 *
173 * \param inode device inode.
174 * \param file_priv DRM file private.
175 * \param cmd command.
176 * \param arg pointer to a drm_auth structure.
177 * \return zero if authentication successed, or a negative number otherwise.
178 *
179 * Checks if \p file_priv is associated with the magic number passed in \arg.
180 * This ioctl needs protection by the drm_global_mutex, which protects
181 * struct drm_file::magic and struct drm_magic_entry::priv.
182 */
183int drm_authmagic(struct drm_device *dev, void *data,
184		  struct drm_file *file_priv)
185{
186	struct drm_auth *auth = data;
187	struct drm_file *file;
188
189	DRM_DEBUG("%u\n", auth->magic);
190	if ((file = drm_find_file(file_priv->master, auth->magic))) {
191		file->authenticated = 1;
192		drm_remove_magic(file_priv->master, auth->magic);
193		return 0;
194	}
195	return -EINVAL;
196}
197
198static int
199drm_magic_init(void *arg)
200{
201
202	mtx_init(&drm_magic_lock, "drm_getmagic__lock", NULL, MTX_DEF);
203	return (0);
204}
205
206static void
207drm_magic_fini(void *arg)
208{
209
210	mtx_destroy(&drm_magic_lock);
211}
212
213SYSINIT(drm_magic_init, SI_SUB_KLD, SI_ORDER_MIDDLE, drm_magic_init, NULL);
214SYSUNINIT(drm_magic_fini, SI_SUB_KLD, SI_ORDER_MIDDLE, drm_magic_fini, NULL);
215