From 9ceb50ed0460a76b14c9f386fdf1d58dff3d5e6d Mon Sep 17 00:00:00 2001
From: Michael Graff <mgraff@isc.org>
Date: Sat, 17 Jun 2000 00:43:11 +0000
Subject: [PATCH] protect isc_entropy_stats() with a lock, and use a static
 dumpstats() internally when a lock is already held, for debugging.  Add
 isc_entropy_putdata() which can be used to prime the pool.

---
 lib/isc/include/isc/entropy.h | 14 ++++++++++++++
 lib/isc/unix/entropy.c        | 35 ++++++++++++++++++++++++++---------
 2 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/lib/isc/include/isc/entropy.h b/lib/isc/include/isc/entropy.h
index 447b3b99c0..ba24e2766a 100644
--- a/lib/isc/include/isc/entropy.h
+++ b/lib/isc/include/isc/entropy.h
@@ -206,8 +206,22 @@ isc_entropy_getdata(isc_entropy_t *ent, void *data, unsigned int length,
  * sources.
  */
 
+void
+isc_entropy_putdata(isc_entropy_t *ent, void *data, unsigned int length,
+		    isc_uint32_t entropy);
+/*
+ * Add "length" bytes in "data" to the entropy pool, incrementing the pool's
+ * entropy count by "entropy."
+ *
+ * These bytes will prime the pseudorandom portion even no entropy is actually
+ * added.
+ */
+
 void
 isc_entropy_stats(isc_entropy_t *ent, FILE *out);
+/*
+ * Dump some (trivial) stats to the stdio stream "out".
+ */
 
 ISC_LANG_ENDDECLS
 
diff --git a/lib/isc/unix/entropy.c b/lib/isc/unix/entropy.c
index 32aa11c106..23688a6cf1 100644
--- a/lib/isc/unix/entropy.c
+++ b/lib/isc/unix/entropy.c
@@ -278,6 +278,7 @@ entropypool_adddata(isc_entropy_t *ent, void *p, unsigned int len,
 	}
 
 	add_entropy(ent, entropy);
+	subtract_pseudo(ent, entropy);
 }
 
 static isc_uint32_t
@@ -436,11 +437,6 @@ fillpool(isc_entropy_t *ent, unsigned int needed, isc_boolean_t blocking) {
 			goto again;
 	}
 
-	/*
-	 * Adjust counts.
-	 */
-	subtract_pseudo(ent, added);
-
 	/*
 	 * Mark as initialized if we've added enough data.
 	 */
@@ -967,13 +963,22 @@ isc_entropy_addsample(isc_entropysource_t *source, isc_uint32_t sample,
 	UNLOCK(&ent->lock);
 }
 
-/*
- * This function ignores locking.  Use at your own risk.
- */
 void
-isc_entropy_stats(isc_entropy_t *ent, FILE *out) {
+isc_entropy_putdata(isc_entropy_t *ent, void *data, unsigned int length,
+		    isc_uint32_t entropy)
+{
 	REQUIRE(VALID_ENTROPY(ent));
 
+	LOCK(&ent->lock);
+	entropypool_adddata(ent, data, length, entropy);
+
+	if (ent->initialized < THRESHOLD_BITS)
+		ent->initialized = THRESHOLD_BITS;
+	UNLOCK(&ent->lock);
+}
+
+static void
+dumpstats(isc_entropy_t *ent, FILE *out) {
 	fprintf(out,
 		"Entropy pool %p:  refcnt %u"
 		" cursor %u, rotate %u entropy %u pseudo %u nsources %u"
@@ -984,6 +989,18 @@ isc_entropy_stats(isc_entropy_t *ent, FILE *out) {
 		ent->nsources, ent->nextsource, ent->initialized);
 }
 
+/*
+ * This function ignores locking.  Use at your own risk.
+ */
+void
+isc_entropy_stats(isc_entropy_t *ent, FILE *out) {
+	REQUIRE(VALID_ENTROPY(ent));
+
+	LOCK(&ent->lock);
+	dumpstats(ent, out);
+	UNLOCK(&ent->lock);
+}
+
 void
 isc_entropy_attach(isc_entropy_t *ent, isc_entropy_t **entp) {
 	REQUIRE(VALID_ENTROPY(ent));