sys/dev/drm/drm_auth.c

   1 /*-
   2  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
   3  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the next
  14  * paragraph) shall be included in all copies or substantial portions of the
  15  * Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  *
  25  * Authors:
  26  *    Rickard E. (Rik) Faith <faith@valinux.com>
  27  *    Gareth Hughes <gareth@valinux.com>
  28  *
  29  * $DragonFly: src/sys/dev/drm/drm_auth.c,v 1.2 2008/06/10 06:35:59 hasso Exp $
  30  */
  31
  32 /** @file drm_auth.c
  33  * Implementation of the get/authmagic ioctls implementing the authentication
  34  * scheme between the master and clients.
  35  */
  36
  37 #include "drmP.h"
  38
  39 static int drm_hash_magic(drm_magic_t magic)
  40 {
  41         return magic & (DRM_HASH_SIZE-1);
  42 }
  43
  44 /**
  45  * Returns the file private associated with the given magic number.
  46  */
  47 static drm_file_t *drm_find_file(drm_device_t *dev, drm_magic_t magic)
  48 {
  49         drm_magic_entry_t *pt;
  50         int hash = drm_hash_magic(magic);
  51
  52         DRM_SPINLOCK_ASSERT(&dev->dev_lock);
  53
  54         for (pt = dev->magiclist[hash].head; pt; pt = pt->next) {
  55                 if (pt->magic == magic) {
  56                         return pt->priv;
  57                 }
  58         }
  59
  60         return NULL;
  61 }
  62
  63 /**
  64  * Inserts the given magic number into the hash table of used magic number
  65  * lists.
  66  */
  67 static int drm_add_magic(drm_device_t *dev, drm_file_t *priv, drm_magic_t magic)
  68 {
  69         int               hash;
  70         drm_magic_entry_t *entry;
  71
  72         DRM_DEBUG("%d\n", magic);
  73
  74         DRM_SPINLOCK_ASSERT(&dev->dev_lock);
  75
  76         hash = drm_hash_magic(magic);
  77         entry = malloc(sizeof(*entry), M_DRM, M_ZERO | M_NOWAIT);
  78         if (!entry) return ENOMEM;
  79         entry->magic = magic;
  80         entry->priv  = priv;
  81         entry->next  = NULL;
  82
  83         if (dev->magiclist[hash].tail) {
  84                 dev->magiclist[hash].tail->next = entry;
  85                 dev->magiclist[hash].tail       = entry;
  86         } else {
  87                 dev->magiclist[hash].head       = entry;
  88                 dev->magiclist[hash].tail       = entry;
  89         }
  90
  91         return 0;
  92 }
  93
  94 /**
  95  * Removes the given magic number from the hash table of used magic number
  96  * lists.
  97  */
  98 static int drm_remove_magic(drm_device_t *dev, drm_magic_t magic)
  99 {
 100         drm_magic_entry_t *prev = NULL;
 101         drm_magic_entry_t *pt;
 102         int               hash;
 103
 104         DRM_SPINLOCK_ASSERT(&dev->dev_lock);
 105
 106         DRM_DEBUG("%d\n", magic);
 107         hash = drm_hash_magic(magic);
 108
 109         for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) {
 110                 if (pt->magic == magic) {
 111                         if (dev->magiclist[hash].head == pt) {
 112                                 dev->magiclist[hash].head = pt->next;
 113                         }
 114                         if (dev->magiclist[hash].tail == pt) {
 115                                 dev->magiclist[hash].tail = prev;
 116                         }
 117                         if (prev) {
 118                                 prev->next = pt->next;
 119                         }
 120                         return 0;
 121                 }
 122         }
 123
 124         free(pt, M_DRM);
 125         return EINVAL;
 126 }
 127
 128 /**
 129  * Called by the client, this returns a unique magic number to be authorized
 130  * by the master.
 131  *
 132  * The master may use its own knowledge of the client (such as the X
 133  * connection that the magic is passed over) to determine if the magic number
 134  * should be authenticated.
 135  */
 136 int drm_getmagic(drm_device_t *dev, void *data, struct drm_file *file_priv)
 137 {
 138         static drm_magic_t sequence = 0;
 139         drm_auth_t *auth = data;
 140
 141                                 /* Find unique magic */
 142         if (file_priv->magic) {
 143                 auth->magic = file_priv->magic;
 144         } else {
 145                 DRM_LOCK();
 146                 do {
 147                         int old = sequence;
 148
 149                         auth->magic = old+1;
 150
 151                         if (!atomic_cmpset_int(&sequence, old, auth->magic))
 152                                 continue;
 153                 } while (drm_find_file(dev, auth->magic));
 154                 file_priv->magic = auth->magic;
 155                 drm_add_magic(dev, file_priv, auth->magic);
 156                 DRM_UNLOCK();
 157         }
 158
 159         DRM_DEBUG("%u\n", auth->magic);
 160
 161         return 0;
 162 }
 163
 164 /**
 165  * Marks the client associated with the given magic number as authenticated.
 166  */
 167 int drm_authmagic(drm_device_t *dev, void *data, struct drm_file *file_priv)
 168 {
 169         drm_auth_t *auth = data;
 170         drm_file_t *priv;
 171
 172         DRM_DEBUG("%u\n", auth->magic);
 173
 174         DRM_LOCK();
 175         priv = drm_find_file(dev, auth->magic);
 176         if (priv != NULL) {
 177                 priv->authenticated = 1;
 178                 drm_remove_magic(dev, auth->magic);
 179                 DRM_UNLOCK();
 180                 return 0;
 181         } else {
 182                 DRM_UNLOCK();
 183                 return EINVAL;
 184         }
 185 }