FreeBSD/Linux Kernel Cross Reference
sys/dev/drm2/drm_auth.c

     /**
      * \file drm_auth.c
      * IOCTLs for authentication
      *
      * \author Rickard E. (Rik) Faith <faith@valinux.com>
      * \author Gareth Hughes <gareth@valinux.com>
      */
     
     /*
     * Created: Tue Feb  2 08:37:54 1999 by faith@valinux.com
     *
     * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
     * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
     * All Rights Reserved.
     *
     * Permission is hereby granted, free of charge, to any person obtaining a
     * copy of this software and associated documentation files (the "Software"),
     * to deal in the Software without restriction, including without limitation
     * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     * and/or sell copies of the Software, and to permit persons to whom the
     * Software is furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice (including the next
     * paragraph) shall be included in all copies or substantial portions of the
     * Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
     * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     * OTHER DEALINGS IN THE SOFTWARE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <dev/drm2/drmP.h>
    
    static struct mtx drm_magic_lock;
    
    /**
     * Find the file with the given magic number.
     *
     * \param dev DRM device.
     * \param magic magic number.
     *
     * Searches in drm_device::magiclist within all files with the same hash key
     * the one with matching magic number, while holding the drm_device::struct_mutex
     * lock.
     */
    static struct drm_file *drm_find_file(struct drm_master *master, drm_magic_t magic)
    {
            struct drm_file *retval = NULL;
            struct drm_magic_entry *pt;
            struct drm_hash_item *hash;
            struct drm_device *dev = master->minor->dev;
    
            DRM_LOCK(dev);
            if (!drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) {
                    pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
                    retval = pt->priv;
            }
            DRM_UNLOCK(dev);
            return retval;
    }
    
    /**
     * Adds a magic number.
     *
     * \param dev DRM device.
     * \param priv file private data.
     * \param magic magic number.
     *
     * Creates a drm_magic_entry structure and appends to the linked list
     * associated the magic number hash key in drm_device::magiclist, while holding
     * the drm_device::struct_mutex lock.
     */
    static int drm_add_magic(struct drm_master *master, struct drm_file *priv,
                             drm_magic_t magic)
    {
            struct drm_magic_entry *entry;
            struct drm_device *dev = master->minor->dev;
            DRM_DEBUG("%d\n", magic);
    
            entry = malloc(sizeof(*entry), DRM_MEM_MAGIC, M_ZERO | M_NOWAIT);
            if (!entry)
                    return -ENOMEM;
            entry->priv = priv;
            entry->hash_item.key = (unsigned long)magic;
            DRM_LOCK(dev);
            drm_ht_insert_item(&master->magiclist, &entry->hash_item);
            list_add_tail(&entry->head, &master->magicfree);
            DRM_UNLOCK(dev);
    
            return 0;
    }
    
   /**
    * Remove a magic number.
    *
    * \param dev DRM device.
    * \param magic magic number.
    *
    * Searches and unlinks the entry in drm_device::magiclist with the magic
    * number hash key, while holding the drm_device::struct_mutex lock.
    */
   int drm_remove_magic(struct drm_master *master, drm_magic_t magic)
   {
           struct drm_magic_entry *pt;
           struct drm_hash_item *hash;
           struct drm_device *dev = master->minor->dev;
   
           DRM_DEBUG("%d\n", magic);
   
           DRM_LOCK(dev);
           if (drm_ht_find_item(&master->magiclist, (unsigned long)magic, &hash)) {
                   DRM_UNLOCK(dev);
                   return -EINVAL;
           }
           pt = drm_hash_entry(hash, struct drm_magic_entry, hash_item);
           drm_ht_remove_item(&master->magiclist, hash);
           list_del(&pt->head);
           DRM_UNLOCK(dev);
   
           free(pt, DRM_MEM_MAGIC);
   
           return 0;
   }
   
   /**
    * Get a unique magic number (ioctl).
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg pointer to a resulting drm_auth structure.
    * \return zero on success, or a negative number on failure.
    *
    * If there is a magic number in drm_file::magic then use it, otherwise
    * searches an unique non-zero magic number and add it associating it with \p
    * file_priv.
    * This ioctl needs protection by the drm_global_mutex, which protects
    * struct drm_file::magic and struct drm_magic_entry::priv.
    */
   int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
   {
           static drm_magic_t sequence = 0;
           struct drm_auth *auth = data;
   
           /* Find unique magic */
           if (file_priv->magic) {
                   auth->magic = file_priv->magic;
           } else {
                   do {
                           mtx_lock(&drm_magic_lock);
                           if (!sequence)
                                   ++sequence;     /* reserve 0 */
                           auth->magic = sequence++;
                           mtx_unlock(&drm_magic_lock);
                   } while (drm_find_file(file_priv->master, auth->magic));
                   file_priv->magic = auth->magic;
                   drm_add_magic(file_priv->master, file_priv, auth->magic);
           }
   
           DRM_DEBUG("%u\n", auth->magic);
   
           return 0;
   }
   
   /**
    * Authenticate with a magic.
    *
    * \param inode device inode.
    * \param file_priv DRM file private.
    * \param cmd command.
    * \param arg pointer to a drm_auth structure.
    * \return zero if authentication successed, or a negative number otherwise.
    *
    * Checks if \p file_priv is associated with the magic number passed in \arg.
    * This ioctl needs protection by the drm_global_mutex, which protects
    * struct drm_file::magic and struct drm_magic_entry::priv.
    */
   int drm_authmagic(struct drm_device *dev, void *data,
                     struct drm_file *file_priv)
   {
           struct drm_auth *auth = data;
           struct drm_file *file;
   
           DRM_DEBUG("%u\n", auth->magic);
           if ((file = drm_find_file(file_priv->master, auth->magic))) {
                   file->authenticated = 1;
                   drm_remove_magic(file_priv->master, auth->magic);
                   return 0;
           }
           return -EINVAL;
   }
   
   static int
   drm_magic_init(void *arg)
   {
   
           mtx_init(&drm_magic_lock, "drm_getmagic__lock", NULL, MTX_DEF);
           return (0);
   }
   
   static void
   drm_magic_fini(void *arg)
   {
   
           mtx_destroy(&drm_magic_lock);
   }
   
   SYSINIT(drm_magic_init, SI_SUB_KLD, SI_ORDER_MIDDLE, drm_magic_init, NULL);
   SYSUNINIT(drm_magic_fini, SI_SUB_KLD, SI_ORDER_MIDDLE, drm_magic_fini, NULL);

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