From 3a6c348fba8ca00ff22315a0e270eca5bc55e84d Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Mon, 19 Sep 2005 16:40:56 +0000
Subject: OpenBSD lets you open /dev/random but not read it!

---
 src/lib9/truerand.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

(limited to 'src')

diff --git a/src/lib9/truerand.c b/src/lib9/truerand.c
index 04462e27..b3c343ef 100644
--- a/src/lib9/truerand.c
+++ b/src/lib9/truerand.c
@@ -7,17 +7,19 @@ truerand(void)
 	int i, n;
 	uchar buf[sizeof(ulong)];
 	static int randfd = -1;
+	static char *randfile;
 
 	if(randfd < 0){
-		randfd = open("/dev/random", OREAD);
-		if(randfd < 0)
-			randfd = open("/dev/srandom", OREAD);	/* OpenBSD */
+		randfd = open(randfile="/dev/random", OREAD);
+		/* OpenBSD lets you open /dev/random but not read it! */
+		if(randfd < 0 || read(randfd, buf, 1) != 1)
+			randfd = open(randfile="/dev/srandom", OREAD);	/* OpenBSD */
 		if(randfd < 0)
 			sysfatal("can't open /dev/random: %r");
 		fcntl(randfd, F_SETFD, FD_CLOEXEC);
 	}
 	for(i=0; i<sizeof(buf); i += n)
 		if((n = readn(randfd, buf+i, sizeof(buf)-i)) < 0)
-			sysfatal("can't read /dev/random: %r");
+			sysfatal("can't read %s: %r", randfile);
 	return *((ulong*)buf);
 }
-- 
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