Add new drmGetNodeTypeFromFd function

Add a helper function that returns the type of device node from an fd.

Signed-off-by: Frank Binns <frank.binns@imgtec.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

2 files changed, 40 insertions, 0 deletions

diff --git a/xf86drm.c b/xf86drm.c
index d85115ca..e117bc63 100644
--- a/xf86drm.c
+++ b/xf86drm.c
@@ -505,6 +505,23 @@ static int drmGetMinorBase(int type)
     };
 }
 
+static int drmGetMinorType(int minor)
+{
+    int type = minor >> 6;
+
+    if (minor < 0)
+        return -1;
+
+    switch (type) {
+    case DRM_NODE_PRIMARY:
+    case DRM_NODE_CONTROL:
+    case DRM_NODE_RENDER:
+        return type;
+    default:
+        return -1;
+    }
+}
+
 /**
  * Open the device by bus ID.
  *
@@ -2667,6 +2684,28 @@ char *drmGetDeviceNameFromFd(int fd)
 	return strdup(name);
 }
 
+int drmGetNodeTypeFromFd(int fd)
+{
+	struct stat sbuf;
+	int maj, min, type;
+
+	if (fstat(fd, &sbuf))
+		return -1;
+
+	maj = major(sbuf.st_rdev);
+	min = minor(sbuf.st_rdev);
+
+	if (maj != DRM_MAJOR || !S_ISCHR(sbuf.st_mode)) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	type = drmGetMinorType(min);
+	if (type == -1)
+		errno = ENODEV;
+	return type;
+}
+
 int drmPrimeHandleToFD(int fd, uint32_t handle, uint32_t flags, int *prime_fd)
 {
 	struct drm_prime_handle args;
diff --git a/xf86drm.h b/xf86drm.h
index 77937eb9..afd38a10 100644
--- a/xf86drm.h
+++ b/xf86drm.h
@@ -744,6 +744,7 @@ typedef struct _drmEventContext {
 extern int drmHandleEvent(int fd, drmEventContextPtr evctx);
 
 extern char *drmGetDeviceNameFromFd(int fd);
+extern int drmGetNodeTypeFromFd(int fd);
 
 extern int drmPrimeHandleToFD(int fd, uint32_t handle, uint32_t flags, int *prime_fd);
 extern int drmPrimeFDToHandle(int fd, int prime_fd, uint32_t *handle);