xref: /openbmc/qemu/util/drm.c (revision 53ba2eee)
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 }
76