Fastbootd: flashing certification

Change-Id: I564086908942463eebee69449d484ba03effc50e
diff --git a/fastbootd/utils.c b/fastbootd/utils.c
index 16e1c09..8205af4 100644
--- a/fastbootd/utils.c
+++ b/fastbootd/utils.c
@@ -34,6 +34,7 @@
 #include <stdio.h>
 #include <sys/ioctl.h>
 #include <linux/fs.h>
+#include <stdlib.h>
 
 #include "utils.h"
 #include "debug.h"
@@ -145,3 +146,15 @@
     return 0;
 }
 
+int create_temp_file() {
+    char tempname[] = "/dev/fastboot_data_XXXXXX";
+    int fd;
+
+    fd = mkstemp(tempname);
+    if (fd < 0)
+        return -1;
+
+    unlink(tempname);
+
+    return fd;
+}