From 62976c688b92151191a4b3d80d514ad09f75d349 Mon Sep 17 00:00:00 2001
From: Ciro Santilli <ciro.santilli@gmail.com>
Date: Sat, 7 Oct 2017 04:11:08 +0100
Subject: [PATCH] update to qemu v2.9.0! rand_check.c, init_forward.sh

---
 README.md                       |  2 ++
 kernel_module/user/README.md    |  1 +
 kernel_module/user/rand_check.c | 41 +++++++++++++++++++++++++++++++++
 qemu                            |  2 +-
 rootfs_overlay/README.md        |  4 ----
 rootfs_overlay/init_forward.sh  |  6 +++++
 6 files changed, 51 insertions(+), 5 deletions(-)
 create mode 100644 kernel_module/user/rand_check.c
 create mode 100755 rootfs_overlay/init_forward.sh

diff --git a/README.md b/README.md
index e1eb805..fc9dbbe 100644
--- a/README.md
+++ b/README.md
@@ -262,6 +262,8 @@ and they will be run automatically before the login prompt.
 
 For convenience, we also setup a symlink from `S99` to `rootfs_overlay/etc/init.d/S99`.
 
+Scripts under `/etc/init.d` are run by `/etc/init.d/rcS`, which gets called by the line `::sysinit:/etc/init.d/rcS` in `/etc/inittab`.
+
 ### Custom init
 
 Is the default BusyBox `/init` too bloated for you, minimalism freak?
diff --git a/kernel_module/user/README.md b/kernel_module/user/README.md
index 14df18a..8e04599 100644
--- a/kernel_module/user/README.md
+++ b/kernel_module/user/README.md
@@ -18,6 +18,7 @@ These programs can also be compiled and used on host.
         1.  [poweroff](poweroff.c)
         1.  [init_dev_kmsg](init_dev_kmsg.c)
     1.  [uio_read](uio_read.c)
+    1.  [rand_check](rand_check.c)
 1.  Module tests
     1.  [anonymous_inode](anonymous_inode.c)
     1.  [poll](poll.c)
diff --git a/kernel_module/user/rand_check.c b/kernel_module/user/rand_check.c
new file mode 100644
index 0000000..4b8309c
--- /dev/null
+++ b/kernel_module/user/rand_check.c
@@ -0,0 +1,41 @@
+/* Check if we were able to remove certain sources of randomness
+ * across boots using different techniques:
+ *
+ * - QEMU icount record replay
+ * - norandmaps boot parameter
+ *
+ * You might want to run this as the init process to further remove undeterminism. */
+
+#include <inttypes.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+int bss = 0;
+int data = 1;
+
+int main(__attribute__((unused)) int argc, char **argv) {
+	int i, *ip;
+	uint64_t uint64;
+	FILE *fp;
+
+	printf("time(NULL) = %ju\n", (uintmax_t)time(NULL));
+	printf("&i         = %p\n", (void *)&i);
+	printf("&argv[0]   = %p\n", (void *)&argv[0]);
+	printf("&main      = %p\n", (void *)(intptr_t)main);
+	printf("&bss       = %p\n", (void *)&bss);
+	printf("&data      = %p\n", (void *)&data);
+
+	/* malloc */
+	ip = malloc(sizeof(*ip));
+	printf("&malloc    = %p\n", (void *)ip);
+	free(ip);
+
+	/* /dev/urandom */
+	fp = fopen("/dev/urandom", "rb");
+	fread(&uint64, sizeof(uint64), 1, fp);
+	printf("/dev/urandom = %" PRIx64 "\n", uint64);
+	fclose(fp);
+}
diff --git a/qemu b/qemu
index 93203c1..e583d17 160000
--- a/qemu
+++ b/qemu
@@ -1 +1 @@
-Subproject commit 93203c1d8b7bd5c12896157802c89447d7d6a499
+Subproject commit e583d175e4cdfb12b4812a259e45c679743b32ad
diff --git a/rootfs_overlay/README.md b/rootfs_overlay/README.md
index b021b44..1bdc972 100644
--- a/rootfs_overlay/README.md
+++ b/rootfs_overlay/README.md
@@ -6,7 +6,3 @@ We use it to for things like:
 
 - customized configuration files
 - userland module test scripts
-
-Most tests correspond clearly to a given kernel module, but the following ones don't:
-
-- [gpio](gpio.sh)
diff --git a/rootfs_overlay/init_forward.sh b/rootfs_overlay/init_forward.sh
new file mode 100755
index 0000000..7f683a0
--- /dev/null
+++ b/rootfs_overlay/init_forward.sh
@@ -0,0 +1,6 @@
+#!/bin/sh
+# Failed attempt at debugging /init, because:
+#     init must be run as pid 1
+# Is this just a random BusyBox sanity check?
+# - https://stackoverflow.com/questions/35019995/strace-init-process-pid-1-in-linux
+/sbin/init "$@"