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      1 /*
      2  * Copyright (c) 2012 Intel Corporation. All Rights Reserved.
      3  *
      4  * Permission is hereby granted, free of charge, to any person obtaining a
      5  * copy of this software and associated documentation files (the
      6  * "Software"), to deal in the Software without restriction, including
      7  * without limitation the rights to use, copy, modify, merge, publish,
      8  * distribute, sub license, and/or sell copies of the Software, and to
      9  * permit persons to whom the Software is furnished to do so, subject to
     10  * the following conditions:
     11  *
     12  * The above copyright notice and this permission notice (including the
     13  * next paragraph) shall be included in all copies or substantial portions
     14  * of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
     19  * IN NO EVENT SHALL PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR
     20  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     21  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     22  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 #include "sysdeps.h"
     26 #include <unistd.h>
     27 #include <xf86drm.h>
     28 #include "va_drm_auth.h"
     29 #include "va_drm_auth_x11.h"
     30 
     31 #if defined __linux__
     32 # include <sys/syscall.h>
     33 #endif
     34 
     35 /* Checks whether the thread id is the current thread */
     36 static bool
     37 is_local_tid(pid_t tid)
     38 {
     39 #if defined __linux__
     40     /* On Linux systems, drmGetClient() would return the thread ID
     41        instead of the actual process ID */
     42     return syscall(SYS_gettid) == tid;
     43 #else
     44     return false;
     45 #endif
     46 }
     47 
     48 /* Checks whether DRM connection is authenticated */
     49 bool
     50 va_drm_is_authenticated(int fd)
     51 {
     52     pid_t client_pid;
     53     int i, auth, pid, uid;
     54     unsigned long magic, iocs;
     55     bool is_authenticated = false;
     56 
     57     client_pid = getpid();
     58     for (i = 0; !is_authenticated; i++) {
     59         if (drmGetClient(fd, i, &auth, &pid, &uid, &magic, &iocs) != 0)
     60             break;
     61         is_authenticated = auth && (pid == client_pid || is_local_tid(pid));
     62     }
     63     return is_authenticated;
     64 }
     65 
     66 /* Try to authenticate the DRM connection with the supplied magic id */
     67 bool
     68 va_drm_authenticate(int fd, uint32_t magic)
     69 {
     70     /* XXX: try to authenticate through Wayland, etc. */
     71 #ifdef HAVE_VA_X11
     72     if (va_drm_authenticate_x11(fd, magic))
     73         return true;
     74 #endif
     75 
     76     /* Default: root + master privs are needed for the following call */
     77     return drmAuthMagic(fd, magic) == 0;
     78 }
     79