misc

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 42 insertions, 0 deletions

diff --git a/libgamma_linux_drm_site_initialise.c b/libgamma_linux_drm_site_initialise.c
new file mode 100644
index 0000000..81f6e12
--- /dev/null
+++ b/libgamma_linux_drm_site_initialise.c
@@ -0,0 +1,42 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Initialise an allocated site state
+ * 
+ * @param   this    The site state to initialise
+ * @param   site    The site identifier, unless it is `NULL` it must a
+ *                  `free`:able. Once the state is destroyed the library
+ *                  will attempt to free it. There you should not free
+ *                  it yourself, and it must not be a string constant
+ *                  or allocate on the stack. Note however that it will
+ *                  not be free:d if this function fails.
+ * @return          Zero on success, otherwise (negative) the value of an
+ *                  error identifier provided by this library
+ */
+int
+libgamma_linux_drm_site_initialise(libgamma_site_state_t *restrict this, char *restrict site)
+{
+	char pathname[PATH_MAX];
+	struct stat _attr;
+  
+	if (site)
+		return LIBGAMMA_NO_SUCH_SITE;
+
+	/* Count the number of available graphics cards by
+	   `stat`:ing their existence in an API filesystem */
+	this->partitions_available = 0;
+	for (;;) {
+		/* Construct pathname of graphics card device */
+		snprintf(pathname, sizeof(pathname) / sizeof(char),
+		          DRM_DEV_NAME, DRM_DIR_NAME, (int)(this->partitions_available));
+		/* `stat` the graphics card's existence */
+		if (stat(pathname, &_attr))
+			break;
+		/* Move on to next graphics card */
+		if (this->partitions_available++ > INT_MAX)
+			return LIBGAMMA_IMPOSSIBLE_AMOUNT;
+	}
+	return 0;
+}