win32: allow use of shell's PRNG for /dev/urandom

Allow either ISAAC or the shell's built-in pseudo-random number
generator to be used for /dev/urandom.  The latter is smaller so
it's the default.

3 files changed, 15 insertions, 0 deletions

diff --git a/shell/Kbuild.src b/shell/Kbuild.src
index 6bba4989f..a287fce4e 100644
--- a/shell/Kbuild.src
+++ b/shell/Kbuild.src
@@ -9,3 +9,4 @@ lib-y:=
 INSERT
 
 lib-$(CONFIG_FEATURE_SH_MATH) += math.o
+lib-$(CONFIG_FEATURE_PRNG_SHELL) += random.o
diff --git a/shell/random.c b/shell/random.c
index 5d3620516..614172279 100644
--- a/shell/random.c
+++ b/shell/random.c
@@ -19,6 +19,17 @@
 # include "random.h"
 # define RAND_BASH_MASK 0x7fff
 
+# if ENABLE_FEATURE_PRNG_SHELL
+uint32_t FAST_FUNC
+next_random(random_t *rnd)
+{
+        return full_random(rnd) & RAND_BASH_MASK;
+}
+#  undef RAND_BASH_MASK
+#  define RAND_BASH_MASK 0xffffffff
+#  define next_random full_random
+# endif
+
 #else
 # include <stdint.h>
 # include <unistd.h>
diff --git a/shell/random.h b/shell/random.h
index c4eb44c13..75fe0f69f 100644
--- a/shell/random.h
+++ b/shell/random.h
@@ -35,6 +35,9 @@ typedef struct random_t {
         ((rnd)->galois_LFSR = 0)
 
 uint32_t next_random(random_t *rnd) FAST_FUNC;
+#if ENABLE_FEATURE_PRNG_SHELL
+uint32_t full_random(random_t *rnd) FAST_FUNC;
+#endif
 
 POP_SAVED_FUNCTION_VISIBILITY