Add a test-rng program so we can pipe to dieharder.

.gitignore

@@ -248,6 +248,7 @@ uptime-*.json
 /src/test/test-memwipe
 /src/test/test-ntor-cl
 /src/test/test-hs-ntor-cl
+/src/test/test-rng
 /src/test/test-switch-id
 /src/test/test-timers
 /src/test/test_workqueue
@@ -258,6 +259,7 @@ uptime-*.json
 /src/test/test-ntor-cl.exe
 /src/test/test-hs-ntor-cl.exe
 /src/test/test-memwipe.exe
+/src/test/test-rng.exe
 /src/test/test-switch-id.exe
 /src/test/test-timers.exe
 /src/test/test_workqueue.exe

src/test/include.am

@@ -68,7 +68,8 @@ noinst_PROGRAMS+= \
 	src/test/test-process \
 	src/test/test_workqueue \
 	src/test/test-switch-id \
-	src/test/test-timers
+	src/test/test-timers \
+	src/test/test-rng
 endif
 
 src_test_AM_CPPFLAGS = -DSHARE_DATADIR="\"$(datadir)\"" \
@@ -258,7 +259,13 @@ src_test_test_LDADD = \
 src_test_test_slow_CPPFLAGS = $(src_test_test_CPPFLAGS)
 src_test_test_slow_CFLAGS = $(src_test_test_CFLAGS)
 src_test_test_slow_LDADD = $(src_test_test_LDADD)
-src_test_test_slow_LDFLAGS = $(src_test_test_LDFLAGS)
+src_test_test_slow_LDFLAGS =@TOR_LDFLAGS_openssl@
+
+src_test_test_rng_CPPFLAGS = $(src_test_test_CPPFLAGS)
+src_test_test_rng_CFLAGS = $(src_test_test_CFLAGS)
+src_test_test_rng_SOURCES = src/test/test_rng.c
+src_test_test_rng_LDFLAGS =  $(src_test_test_LDFLAGS)
+src_test_test_rng_LDADD = $(src_test_test_LDADD)
 
 src_test_test_memwipe_CPPFLAGS = $(src_test_test_CPPFLAGS)
 # Don't use bugtrap cflags here: memwipe tests require memory violations.

src/test/test_rng.c

@@ -0,0 +1,59 @@
+/* Copyright (c) 2016-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/*
+ * Example usage:
+ *
+ * ./src/test/test-rng --emit | dieharder -g 200 -a
+ *
+ * Remember, dieharder can tell you that your RNG is completely broken, but if
+ * your RNG is not _completely_ broken, dieharder cannot tell you whether your
+ * RNG is actually secure.
+ */
+
+#include "orconfig.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include "lib/crypt_ops/crypto_rand.h"
+
+int
+main(int argc, char **argv)
+{
+  uint8_t buf[0x123];
+
+  if (argc != 2 || strcmp(argv[1], "--emit")) {
+    fprintf(stderr, "If you want me to fill stdout with a bunch of random "
+            "bytes, you need to say --emit.\n");
+    return 1;
+  }
+
+  if (crypto_seed_rng() < 0) {
+    fprintf(stderr, "Can't seed RNG.\n");
+    return 1;
+  }
+
+#if 0
+  while (1) {
+    crypto_rand(buf, sizeof(buf));
+    if (write(1 /*stdout*/, buf, sizeof(buf)) != sizeof(buf)) {
+      fprintf(stderr, "write() failed: %s\n", strerror(errno));
+      return 1;
+    }
+  }
+#endif
+
+  crypto_fast_rng_t *rng = crypto_fast_rng_new();
+  while (1) {
+    crypto_fast_rng_getbytes(rng, buf, sizeof(buf));
+    if (write(1 /*stdout*/, buf, sizeof(buf)) != sizeof(buf)) {
+      fprintf(stderr, "write() failed: %s\n", strerror(errno));
+      return 1;
+    }
+  }
+}