init_dev_kmsg

kernel_module/user/README.md

@@ -16,6 +16,7 @@ These programs can also be compiled and used on host.
     1.  inits
         1.  [sleep_forever](sleep_forever.c)
         1.  [poweroff](poweroff.c)
+        1.  [init_dev_kmsg](init_dev_kmsg.c)
     1.  [uio_read](uio_read.c)
 1.  Module tests
     1.  [anonymous_inode](anonymous_inode.c)

kernel_module/user/init_dev_kmsg.c

@@ -0,0 +1,13 @@
+/* https://stackoverflow.com/questions/12683169/measure-time-taken-for-linux-kernel-from-bootup-to-userpace/46517014#46517014 */
+
+#include <stdio.h>
+#include <unistd.h>
+
+int main(void) {
+    FILE *fp;
+    fp = fopen("/dev/kmsg", "w");
+	fputs(__FILE__ "\n", fp);
+	fclose(fp);
+	while (1)
+		sleep(0xFFFFFFFF);
+}