[PATCH/RFC 5/7] imap-send: provide fall-back random-source

[Erik Faye-Lund <kusmabite@googlemail.com>]

Since some systems (at least Windows) does not have
/dev/random nor friends, we need another random-source.

This patch uses the C-runtime's rand()-function as a
poor-mans random-source.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
---
 imap-send.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/imap-send.c b/imap-send.c
index 8338717..dda7b7f 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -511,14 +511,17 @@ static void arc4_init(void)
 	unsigned char j, si, dat[128];
 
 	if ((fd = open("/dev/urandom", O_RDONLY)) < 0 && (fd = open("/dev/random", O_RDONLY)) < 0) {
-		fprintf(stderr, "Fatal: no random number source available.\n");
-		exit(3);
-	}
-	if (read_in_full(fd, dat, 128) != 128) {
-		fprintf(stderr, "Fatal: cannot read random number source.\n");
-		exit(3);
+		/* poor-mans random-source */
+		srand(clock());
+		for (i = 0; i < 128; ++i)
+			dat[i] = rand() & 0xFF;
+	} else {
+		if (read_in_full(fd, dat, 128) != 128) {
+			fprintf(stderr, "Fatal: cannot read random number source.\n");
+			exit(3);
+		}
+		close(fd);
 	}
-	close(fd);
 
 	for (i = 0; i < 256; i++)
 		rs.s[i] = i;
-- 
1.6.5.rc2.7.g4f8d3