svn commit: r355694 - head/sys/kern

[Conrad Meyer]

Author: cem
Date: Fri Dec 13 04:48:20 2019
New Revision: 355694
URL: https://svnweb.freebsd.org/changeset/base/355694

Log:
  kern/subr_unit: Rip srandomdev, random(3) out of dead code
  
  The simulation cannot be reproduced, so the value of using a deterministic PRNG
  like random(3) is dubious.  The number of repitions used in the sample isn't a
  problem for the Chacha implementation of arc4random we have today.  (Also, no
  one actually runs this code; it was provided as an example of the work the
  author did validating the implementation.  It's not even test code.)

Modified:
  head/sys/kern/subr_unit.c

Modified: head/sys/kern/subr_unit.c
==============================================================================
--- head/sys/kern/subr_unit.c	Fri Dec 13 04:37:39 2019	(r355693)
+++ head/sys/kern/subr_unit.c	Fri Dec 13 04:48:20 2019	(r355694)
@@ -1021,7 +1021,7 @@ main(int argc, char **argv)
 	long count = 10000;	/* Number of unrs to test */
 	long reps = 1, m;
 	int ch;
-	u_int i, j;
+	u_int i;
 
 	verbose = false;
 
@@ -1055,20 +1055,18 @@ main(int argc, char **argv)
 	a = calloc(count, sizeof(char));
 	if (a == NULL)
 		err(1, "calloc failed");
-	srandomdev();
 
 	printf("sizeof(struct unr) %zu\n", sizeof(struct unr));
 	printf("sizeof(struct unrb) %zu\n", sizeof(struct unrb));
 	printf("sizeof(struct unrhdr) %zu\n", sizeof(struct unrhdr));
 	printf("NBITS %lu\n", (unsigned long)NBITS);
 	for (m = 0; m < count * reps; m++) {
-		j = random();
-		i = (j >> 1) % count;
+		i = arc4random_uniform(count);
 #if 0
 		if (a[i] && (j & 1))
 			continue;
 #endif
-		if ((random() & 1) != 0)
+		if ((arc4random() & 1) != 0)
 			test_alloc_unr(uh, i, a);
 		else
 			test_alloc_unr_specific(uh, i, a);