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/dev/random: Add pool name to entropy store

PATCH In review Theodore Ts'o 2 participants 2 messages Aug 20, 2004 – Aug 24, 2004

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#0 lore raw

PATCH 2/4 /dev/random: Add pool name to entropy store

This adds a pool name to the entropy_store data structure, which simplifies the debugging code, and makes the code more generic for adding additional entropy pools.

patch-random-2-pool-name

random.c +15 -21
@@ -493,6 +493,7 @@
 	/* mostly-read data: */
 	struct poolinfo poolinfo;
 	__u32		*pool;
+	const char	*name;
 
 	/* read-write data: */
 	spinlock_t lock ____cacheline_aligned_in_smp;
@@ -507,7 +508,8 @@
  *
  * Returns an negative error if there is a problem.
  */
-static int create_entropy_store(int size, struct entropy_store **ret_bucket)
+static int create_entropy_store(int size, const char *name, 
+				struct entropy_store **ret_bucket)
 {
 	struct	entropy_store	*r;
 	struct	poolinfo	*p;
@@ -538,6 +540,7 @@
 	}
 	memset(r->pool, 0, POOLBYTES);
 	r->lock = SPIN_LOCK_UNLOCKED;
+	r->name = name;
 	*ret_bucket = r;
 	return 0;
 }
@@ -643,12 +646,8 @@
 	} else {
 		r->entropy_count += nbits;
 		if (nbits)
-			DEBUG_ENT("%04d %04d : added %d bits to %s\n",
-				  random_state->entropy_count,
-				  sec_random_state->entropy_count,
-				  nbits,
-				  r == sec_random_state ? "secondary" :
-				  r == random_state ? "primary" : "unknown");
+			DEBUG_ENT("Added %d entropy credits to %s, now %d\n",
+				  nbits, r->name, r->entropy_count);
 	}
 
 	spin_unlock_irqrestore(&r->lock, flags);
@@ -1328,8 +1327,7 @@
 			  "(%d of %d requested)\n",
 			  random_state->entropy_count,
 			  sec_random_state->entropy_count,
-			  r == sec_random_state ? "secondary" : "unknown",
-			  bytes * 8, nbytes * 8, r->entropy_count);
+			  r->name, bytes * 8, nbytes * 8, r->entropy_count);
 
 		bytes=extract_entropy(random_state, tmp, bytes,
 				      EXTRACT_ENTROPY_LIMIT);
@@ -1373,9 +1371,7 @@
 	DEBUG_ENT("%04d %04d : trying to extract %d bits from %s\n",
 		  random_state->entropy_count,
 		  sec_random_state->entropy_count,
-		  nbytes * 8,
-		  r == sec_random_state ? "secondary" :
-		  r == random_state ? "primary" : "unknown");
+		  nbytes * 8, r->name);
 
 	if (flags & EXTRACT_ENTROPY_LIMIT && nbytes >= r->entropy_count / 8)
 		nbytes = r->entropy_count / 8;
@@ -1388,12 +1384,8 @@
 	if (r->entropy_count < random_write_wakeup_thresh)
 		wake_up_interruptible(&random_write_wait);
 
-	DEBUG_ENT("%04d %04d : debiting %d bits from %s%s\n",
-		  random_state->entropy_count,
-		  sec_random_state->entropy_count,
-		  nbytes * 8,
-		  r == sec_random_state ? "secondary" :
-		  r == random_state ? "primary" : "unknown",
+	DEBUG_ENT("Debiting %d entropy credits from %s%s\n",
+		  nbytes * 8, r->name,
 		  flags & EXTRACT_ENTROPY_LIMIT ? "" : " (unlimited)");
 
 	spin_unlock_irqrestore(&r->lock, cpuflags);
@@ -1533,11 +1525,12 @@
 {
 	int i;
 
-	if (create_entropy_store(DEFAULT_POOL_SIZE, &random_state))
+	if (create_entropy_store(DEFAULT_POOL_SIZE, "primary", &random_state))
 		goto err;
 	if (batch_entropy_init(BATCH_ENTROPY_SIZE, random_state))
 		goto err;
-	if (create_entropy_store(SECONDARY_POOL_SIZE, &sec_random_state))
+	if (create_entropy_store(SECONDARY_POOL_SIZE, "secondary", 
+				 &sec_random_state))
 		goto err;
 	clear_entropy_store(random_state);
 	clear_entropy_store(sec_random_state);
@@ -1884,7 +1877,8 @@
 	struct entropy_store	*new_store, *old_store;
 	int			ret;
 	
-	if ((ret = create_entropy_store(poolsize, &new_store)))
+	if ((ret = create_entropy_store(poolsize, random_state->name, 
+					&new_store)))
 		return ret;
 
 	add_entropy_words(new_store, random_state->pool,
#1 lore raw
Quoted 4 lines · Theodore Ts'o

This adds a pool name to the entropy_store data structure, which simplifies the debugging code, and makes the code more generic for adding additional entropy pools.

My version from last year called these "input", "blocking", and "nonblocking", which I think added substantially to the readability here.

Signature · 1 line
Mathematics is the supreme nostalgia of our time.