Remove undefined behavior from sranddev() and

srandomdev(). This doesn't actually work
with any modern C compiler:

In particular, both clang and modern gcc
verisons silently elide any xor operation
with 'junk'.

Approved by:	secteam
MFC after:	3 days

2 files changed, 2 insertions, 4 deletions

diff --git a/lib/libc/stdlib/rand.c b/lib/libc/stdlib/rand.c
index 3835976..7041818 100644
--- a/lib/libc/stdlib/rand.c
+++ b/lib/libc/stdlib/rand.c
@@ -130,10 +130,9 @@ sranddev()
 
 	if (!done) {
 		struct timeval tv;
-		unsigned long junk;
 
 		gettimeofday(&tv, NULL);
-		srand((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec ^ junk);
+		srand((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec);
 	}
 }
 
diff --git a/lib/libc/stdlib/random.c b/lib/libc/stdlib/random.c
index 4a1af54..a3c054e 100644
--- a/lib/libc/stdlib/random.c
+++ b/lib/libc/stdlib/random.c
@@ -312,10 +312,9 @@ srandomdev(void)
 
 	if (!done) {
 		struct timeval tv;
-		volatile unsigned long junk;
 
 		gettimeofday(&tv, NULL);
-		srandom((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec ^ junk);
+		srandom((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec);
 		return;
 	}