1 files changed, 108 insertions, 0 deletions
diff --git a/src/drmgamma.c b/src/drmgamma.c
new file mode 100644
index 0000000..0a8f72f
--- /dev/null
+++ b/src/drmgamma.c
@@ -0,0 +1,108 @@
+/**
+ * crt-calibrator – Calibration utility for CRT monitors
+ * Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "drmgamma.h"
+
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+
+
+/**
+ * Close on exec flag for `open`
+ */
+#ifndef O_CLOEXEC
+# define O_CLOEXEC  02000000
+#endif
+
+
+/**
+ * The number of elements to allocates to a buffer for a DRM device pathname
+ */
+#define DRM_DEV_NAME_MAX_LEN  \
+  ((sizeof(DRM_DEV_NAME) + sizeof(DRM_DIR_NAME)) / sizeof(char) + 3 * sizeof(int))
+
+
+
+/**
+ * Figure out how many graphics cards there are on the system
+ * 
+ * @return  The number of graphics cards on the system
+ */
+size_t drm_card_count(void)
+{
+  char buf[DRM_DEV_NAME_MAX_LEN];
+  size_t count = 0;
+  
+  for (;; count++)
+    {
+      sprintf(buf, DRM_DEV_NAME, DRM_DIR_NAME, (int)count);
+      if (access(buf, F_OK) < 0)
+	return count;
+    }
+
+}
+
+/**
+ * Acquire access to a graphics card
+ * 
+ * @param   index  The index of the graphics card
+ * @param   card   Graphics card information to fill in
+ * @return         Zero on success, -1 on error
+ */
+int drm_card_open(size_t index, drm_card_t* restrict card)
+{
+  char buf[DRM_DEV_NAME_MAX_LEN];
+  int old_errno;
+  
+  card->fd = -1;
+  card->res = NULL;
+  
+  sprintf(buf, DRM_DEV_NAME, DRM_DIR_NAME, (int)index);
+  card->fd = open(buf, O_RDWR | O_CLOEXEC);
+  if (card->fd == -1)
+    goto fail;
+  
+  card->res = drmModeGetResources(card->fd);
+  if (card->res == NULL)
+    goto fail;
+  
+  card->crtc_count = (size_t)(card->res->count_crtcs);
+  
+  return 0;
+ fail:
+  old_errno = errno;
+  drm_card_close(card);
+  errno = old_errno;
+  return -1;
+}
+
+
+/**
+ * Release access to a graphics card
+ * 
+ * @param  card  The graphics card information
+ */
+void drm_card_close(drm_card_t* restrict card)
+{
+  if (card->res != NULL)
+    drmModeFreeResources(card->res), card->res = NULL;
+  if (card->fd != -1)
+    close(card->fd), card->fd = -1;
+}