From 0ffa041f367f5aca58a0cbb0f3f82cd88a436c14 Mon Sep 17 00:00:00 2001
From: Con Kolivas <kernel@kolivas.org>
Date: Tue, 15 Mar 2011 12:56:23 +1100
Subject: [PATCH] Add function to get a stream of random numbers into a buffer
 from /dev/urandom if possible, and falling back to random() if not.

---
 util.c | 20 ++++++++++++++++++++
 util.h |  1 +
 2 files changed, 21 insertions(+)

diff --git a/util.c b/util.c
index 50da3e1..6f207c4 100644
--- a/util.c
+++ b/util.c
@@ -45,7 +45,11 @@
 # define PAGE_SIZE (4096)
 #endif
 
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include "lrzip_private.h"
+#include "liblrzip.h"
 
 static const char *infile = NULL;
 static char delete_infile = 0;
@@ -122,3 +126,19 @@ void round_to_page(i64 *size)
 	if (unlikely(!*size))
 		*size = PAGE_SIZE;
 }
+
+void get_rand(uchar *buf, int len)
+{
+	int fd, i;
+
+	fd = open("/dev/urandom", O_RDONLY);
+	if (fd == -1) {
+		for (i = 0; i < len; i++)
+			buf[i] = (uchar)random();
+	} else {
+		if (unlikely(read(fd, buf, len) != len))
+			fatal("Failed to read fd in get_rand\n");
+		if (unlikely(close(fd)))
+			fatal("Failed to close fd in get_rand\n");
+	}
+}
diff --git a/util.h b/util.h
index 612517b..222d81d 100644
--- a/util.h
+++ b/util.h
@@ -28,5 +28,6 @@ void register_outputfile(FILE *f);
 void fatal(const char *format, ...);
 void failure(const char *format, ...);
 void round_to_page(i64 *size);
+void get_rand(uchar *buf, int len);
 
 #endif