io/drm/drm_auth.c

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * drm_auth.h -- IOCTLs for authentication -*- linux-c -*-
 * 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.
 *
 * Authors:
 *    Rickard E. (Rik) Faith <faith@valinux.com>
 *    Gareth Hughes <gareth@valinux.com>
 *
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "drmP.h"

static int
drm_hash_magic(drm_magic_t magic)
{
    return (magic & (DRM_HASH_SIZE-1));
}

drm_file_t *
drm_find_file(drm_device_t *dev, drm_magic_t magic)
{
    drm_file_t    *retval = NULL;
    drm_magic_entry_t *pt;
    int       hash;

    hash = drm_hash_magic(magic);
    for (pt = dev->magiclist[hash].head; pt; pt = pt->next) {
        if (pt->magic == magic) {
            retval = pt->priv;
            break;
        }
    }

    return (retval);
}

static int
drm_add_magic(drm_device_t *dev, drm_file_t *priv, drm_magic_t magic)
{
    int       hash;
    drm_magic_entry_t *entry;

    hash = drm_hash_magic(magic);
    entry = drm_alloc(sizeof (*entry), DRM_MEM_MAGIC);
    if (!entry)
        return (ENOMEM);
    entry->magic = magic;
    entry->priv  = priv;
    entry->next  = NULL;

    DRM_LOCK();
    if (dev->magiclist[hash].tail) {
        dev->magiclist[hash].tail->next = entry;
        dev->magiclist[hash].tail   = entry;
    } else {
        dev->magiclist[hash].head   = entry;
        dev->magiclist[hash].tail   = entry;
    }
    DRM_UNLOCK();

    return (0);
}

int
drm_remove_magic(drm_device_t *dev, drm_magic_t magic)
{
    drm_magic_entry_t *prev = NULL;
    drm_magic_entry_t *pt;
    int       hash;

    DRM_DEBUG("drm_remove_magic : %d", magic);
    hash = drm_hash_magic(magic);

    DRM_LOCK();
    for (pt = dev->magiclist[hash].head; pt; prev = pt, pt = pt->next) {
        if (pt->magic == magic) {
            if (dev->magiclist[hash].head == pt) {
                dev->magiclist[hash].head = pt->next;
            }
            if (dev->magiclist[hash].tail == pt) {
                dev->magiclist[hash].tail = prev;
            }
            if (prev) {
                prev->next = pt->next;
            }
            DRM_UNLOCK();
            drm_free(pt, sizeof (*pt), DRM_MEM_MAGIC);
            return (0);
        }
    }
    DRM_UNLOCK();

    return (EINVAL);
}

/*ARGSUSED*/
int
drm_getmagic(DRM_IOCTL_ARGS)
{
    DRM_DEVICE;
    static drm_magic_t sequence = 0;
    drm_auth_t auth;

    /* Find unique magic */
    if (fpriv->magic) {
        auth.magic = fpriv->magic;
    } else {
        do {
            int old = sequence;
            auth.magic = old+1;
            if (!atomic_cmpset_int(&sequence, old, auth.magic))
                continue;
        } while (drm_find_file(dev, auth.magic));
        fpriv->magic = auth.magic;
        (void) drm_add_magic(dev, fpriv, auth.magic);
    }


    DRM_DEBUG("drm_getmagic: %u", auth.magic);

    DRM_COPYTO_WITH_RETURN((void *)data, &auth, sizeof (auth));

    return (0);
}

/*ARGSUSED*/
int
drm_authmagic(DRM_IOCTL_ARGS)
{
    drm_auth_t     auth;
    drm_file_t     *file;
    DRM_DEVICE;

    DRM_COPYFROM_WITH_RETURN(&auth, (void *)data, sizeof (auth));

    if ((file = drm_find_file(dev, auth.magic))) {
        file->authenticated = 1;
        (void) drm_remove_magic(dev, auth.magic);
        return (0);
    }
    return (EINVAL);
}