If /dev/random is available, use it to seed the PRNG.

diff --git a/v7/src/runtime/random.scm b/v7/src/runtime/random.scm
index 0cd61df3a70b32da2bc1e605e58308d0b0163557..2a19e7317f964bc19f6fda30fa2caa701b4650c1 100644 (file)
--- a/v7/src/runtime/random.scm
+++ b/v7/src/runtime/random.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Id: random.scm,v 14.18 1999/01/02 06:11:34 cph Exp $
+$Id: random.scm,v 14.19 1999/08/09 19:08:50 cph Exp $
 
 Copyright (c) 1993-1999 Massachusetts Institute of Technology
 
@@ -91,7 +91,20 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   (let ((state (if (default-object? state) #f state)))
     (if (or (eq? #t state) (int:integer? state))
        (initial-random-state
-        (congruential-rng (+ (real-time-clock) 123456789)))
+        (congruential-rng
+         ;; Use good random source if available
+         (if (file-exists? "/dev/urandom")
+             (call-with-input-file "/dev/urandom"
+               (lambda (port)
+                 (let* ((b1 (char->integer (read-char port)))
+                        (b2 (char->integer (read-char port)))
+                        (b3 (char->integer (read-char port)))
+                        (b4 (char->integer (read-char port))))
+                   (+ (* b1 #x1000000)
+                      (* b2 #x10000)
+                      (* b3 #x100)
+                      b4))))
+             (+ (real-time-clock) 123456789))))
        (copy-random-state
         (guarantee-random-state state 'MAKE-RANDOM-STATE)))))