util: promote qemu_egl_rendernode_open() to libqemuutil

vhost-user-gpu will share the same code to open a DRM node.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180713130916.4153-20-marcandre.lureau@redhat.com>

[ kraxel: buildfix: util/drm.o must be CONFIG_OPENGL not CONFIG_LINUX ]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

2 files changed, 67 insertions, 0 deletions

diff --git a/util/Makefile.objs b/util/Makefile.objs
index e1c3fed4dc..4726d262d8 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -49,3 +49,4 @@ util-obj-y += stats64.o
 util-obj-y += systemd.o
 util-obj-y += iova-tree.o
 util-obj-$(CONFIG_LINUX) += vfio-helpers.o
+util-obj-$(CONFIG_OPENGL) += drm.o
diff --git a/util/drm.c b/util/drm.c
new file mode 100644
index 0000000000..a23ff24538
--- /dev/null
+++ b/util/drm.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2015-2016 Gerd Hoffmann <kraxel@redhat.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include "qemu/osdep.h"
+#include "qemu/drm.h"
+
+#include <glob.h>
+#include <dirent.h>
+
+int qemu_drm_rendernode_open(const char *rendernode)
+{
+    DIR *dir;
+    struct dirent *e;
+    int r, fd;
+    char *p;
+
+    if (rendernode) {
+        return open(rendernode, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
+    }
+
+    dir = opendir("/dev/dri");
+    if (!dir) {
+        return -1;
+    }
+
+    fd = -1;
+    while ((e = readdir(dir))) {
+        if (e->d_type != DT_CHR) {
+            continue;
+        }
+
+        if (strncmp(e->d_name, "renderD", 7)) {
+            continue;
+        }
+
+        p = g_strdup_printf("/dev/dri/%s", e->d_name);
+
+        r = open(p, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
+        if (r < 0) {
+            g_free(p);
+            continue;
+        }
+        fd = r;
+        g_free(p);
+        break;
+    }
+
+    closedir(dir);
+    if (fd < 0) {
+        return -1;
+    }
+    return fd;
+}