From c0c228b758150e017185dc280ef020ec3b7efdcf Mon Sep 17 00:00:00 2001
From: Euan Torano <euantorano@gmail.com>
Date: Fri, 2 Aug 2019 13:19:49 +0100
Subject: [PATCH] Check if /dev/urandom is a character device

---
 std/os.zig | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/std/os.zig b/std/os.zig
index 9ff2e8f87..da1d71d6f 100644
--- a/std/os.zig
+++ b/std/os.zig
@@ -133,6 +133,11 @@ fn getRandomBytesDevURandom(buf: []u8) !void {
     const fd = try openC(c"/dev/urandom", O_RDONLY | O_CLOEXEC, 0);
     defer close(fd);
 
+    const st = try fstat(fd);
+    if (!S_ISCHR(st.mode)) {
+        return OpenError.Unexpected;
+    }
+
     const stream = &std.fs.File.openHandle(fd).inStream().stream;
     stream.readNoEof(buf) catch return error.Unexpected;
 }