util/drm.c

   1 /*
   2  * Copyright (C) 2015-2016 Gerd Hoffmann <kraxel@redhat.com>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17 #include "qemu/osdep.h"
  18 #include "qemu/drm.h"
  19
  20 #include <glob.h>
  21 #include <dirent.h>
  22
  23 int qemu_drm_rendernode_open(const char *rendernode)
  24 {
  25     DIR *dir;
  26     struct dirent *e;
  27     struct stat st;
  28     int r, fd, ret;
  29     char *p;
  30
  31     if (rendernode) {
  32         return open(rendernode, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
  33     }
  34
  35     dir = opendir("/dev/dri");
  36     if (!dir) {
  37         return -1;
  38     }
  39
  40     fd = -1;
  41     while ((e = readdir(dir))) {
  42         if (strncmp(e->d_name, "renderD", 7)) {
  43             continue;
  44         }
  45
  46         p = g_strdup_printf("/dev/dri/%s", e->d_name);
  47
  48         r = open(p, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
  49         if (r < 0) {
  50             g_free(p);
  51             continue;
  52         }
  53
  54         /*
  55          * prefer fstat() over checking e->d_type == DT_CHR for
  56          * portability reasons
  57          */
  58         ret = fstat(r, &st);
  59         if (ret < 0 || (st.st_mode & S_IFMT) != S_IFCHR) {
  60             close(r);
  61             g_free(p);
  62             continue;
  63         }
  64
  65         fd = r;
  66         g_free(p);
  67         break;
  68     }
  69
  70     closedir(dir);
  71     if (fd < 0) {
  72         return -1;
  73     }
  74     return fd;
  75 }