Rm useless init.sh, init_hello and poweroff are not init specific, so rename them more generically

README.md

@@ -264,11 +264,16 @@ Is the default BusyBox `/init` too bloated for you, minimalism freak?
 
 No problem, just use the `init` kernel boot parameter:
 
-    ./runqemu -e 'init=/init_hello.out'
+    ./runqemu -e 'init=/sleep_forever.out'
 
 Remember that shell scripts can also be used for `init` <https://unix.stackexchange.com/questions/174062/init-as-a-shell-script/395375#395375>:
 
-    ./runqemu -e 'init=/init.sh'
+    ./runqemu -e 'init=/count.sh'
+
+Also remember that if your init returns, the kernel will panic, there are just two non-panic possibilities:
+
+- run forever in a loop or long sleep
+- `poweroff` the machine
 
 ## Debugging
 

kernel_module/user/README.md

@@ -14,8 +14,8 @@ These programs can also be compiled and used on host.
     1.  [usermem](usermem.c)
         1.  [pagemap_dump](pagemap_dump.c)
     1.  inits
-        1.  [init_hello](init_hello.c)
+        1.  [sleep_forever](sleep_forever.c)
-        1.  [init_poweroff](init_poweroff.c)
+        1.  [poweroff](poweroff.c)
     1.  [uio_read](uio_read.c)
 1.  Module tests
     1.  [anonymous_inode](anonymous_inode.c)

kernel_module/user/init_hello.c

@@ -1,11 +0,0 @@
-/* Replacement init example for when we feel like running
- * a single non-interactive single executable Linux distro. */
-
-#include <stdio.h>
-#include <unistd.h>
-
-int main(void) {
-	puts(__FILE__);
-	while (1)
-		sleep(0xFFFFFFFF);
-}

kernel_module/user/poweroff.c

@@ -1,5 +1,6 @@
 /* Userspace is for the weak. Die.
- * https://stackoverflow.com/questions/28812514/how-to-shutdown-linux-using-c-or-qt-without-call-to-system */
+ * https://stackoverflow.com/questions/28812514/how-to-shutdown-linux-using-c-or-qt-without-call-to-system
+ * BusyBox's /sbin/poweroff is under init/halt.c, but it does extra crap like killing init, so I don't trust it. */
 
 #include <stdio.h>
 #include <sys/reboot.h>

kernel_module/user/sleep_forever.c

@@ -0,0 +1,10 @@
+/* Sleeping beauty, your prince is called Ctrl + C. */
+
+#include <stdio.h>
+#include <unistd.h>
+
+int main(void) {
+	puts(__FILE__);
+	while (1)
+		sleep(0xFFFFFFFF);
+}

rootfs_overlay/init.sh

@@ -1,7 +0,0 @@
-#!/bin/sh
-# Can init be a sh script? Yes.
-# Sure, why not: https://unix.stackexchange.com/questions/174062/init-as-a-shell-script/395375#395375
-echo 'hello init.sh'
-while true; do
-  sleep 1
-done