hwrand.pl,hwrand.py: forward randomness

Continuously fills the entropy pool from /dev/hwrng, crediting 4 bits of
entropy per byte. Hopefully speeds up the provisioning of a test VM that
invokes pacman-key --init...

Authored by me, posted on https://unix.stackexchange.com/a/302338/8250

2 files changed, 15 insertions, 0 deletions

diff --git a/hwrand.pl b/hwrand.pl
new file mode 100755
index 0000000..87fd667
--- /dev/null
+++ b/hwrand.pl
@@ -0,0 +1,8 @@
+#!/usr/bin/perl
+open my $hw, "</dev/hwrng" and open my $rnd, "</dev/random" or die;
+for (;;) {
+    my $l = read $hw, my $d, 512;
+    ioctl $rnd, 0x40085203, pack("ii", 4 * $l, $l) . $d or die;
+    vec(my $w, fileno $rnd, 1) = 1;
+    select undef, $w, undef, undef
+}
diff --git a/hwrand.py b/hwrand.py
new file mode 100755
index 0000000..92016a1
--- /dev/null
+++ b/hwrand.py
@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+import fcntl, select, struct
+with open('/dev/hwrng', 'rb') as hw, open('/dev/random') as rnd:
+    while True:
+        d = hw.read(512)
+        fcntl.ioctl(rnd, 0x40085203, struct.pack('ii', 4 * len(d), len(d)) + d)
+        select.select([], [rnd], [])