1 files changed, 10 insertions, 0 deletions
diff --git a/src/main.c b/src/main.c
index 0e67623..3bce0f0 100644
--- a/src/main.c
+++ b/src/main.c
@@ -19,6 +19,7 @@
 #include <string.h>
 #include <time.h>
 #include <errno.h>
+#include <sys/file.h>
 
 #include "config.h"
 
@@ -131,6 +132,14 @@ int fade(struct props* props) {
     return -1;
   }
 
+  // Lock the file descriptor so we can't have conflicting brightness change
+  // operations
+  if(flock(fileno(fd), LOCK_EX | LOCK_NB) != 0) {
+    fprintf(stderr, "Could not obtain brightness file lock\n");
+    fclose(fd);
+    return -1;
+  }
+
   while(opcount > 0) {
     nanosleep(&tim, &tim2);
 
@@ -144,6 +153,7 @@ int fade(struct props* props) {
     opcount--;
   }
 
+  // Do not need to explicitly release the file lock
   fclose(fd);
   return 0;
 }