From 43357218f024b251fc2b741dc3e8bdc4c001051f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Tue, 22 May 2018 18:07:08 +0200
Subject: [PATCH 3/3] gnu: e2fsprogs: Use libuuid with non-blocking random.

Partly fixes <https://bugs.gnu.org/31268>.

* gnu/packages/linux.scm (util-linux/libuuid-non-blocking-random): New
variable.
(e2fsprogs)[inputs]: Use it instead of UTIL-LINUX.
---
 gnu/packages/linux.scm                          | 17 ++++++++++++++++-
 ...util-linux-libuuid-non-blocking-random.patch | 15 +++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 gnu/packages/patches/util-linux-libuuid-non-blocking-random.patch

diff --git a/gnu/packages/linux.scm b/gnu/packages/linux.scm
index bb4e00394..c93947e68 100644
--- a/gnu/packages/linux.scm
+++ b/gnu/packages/linux.scm
@@ -671,6 +671,20 @@ block devices, UUIDs, TTYs, and many other tools.")
                 (append (origin-patches (package-source util-linux))
                         (search-patches "util-linux-CVE-2018-7738.patch")))))))
 
+(define-public util-linux/libuuid-non-blocking-random
+  ;; Package variant where libuuid uses non-blocking (weak) random.  See
+  ;; <https://bugs.gnu.org/31268>.
+  (package
+    (inherit util-linux)
+    (name "util-linux-weak-random")
+    (source (let ((source (package-source util-linux)))
+              (origin
+                (inherit source)
+                (patches (append (search-patches
+                                  "util-linux-libuuid-non-blocking-random.patch")
+                                 (origin-patches source))))))
+    (properties '((hidden? . #t)))))
+
 (define-public ddate
   (package
     (name "ddate")
@@ -779,7 +793,8 @@ slabtop, and skill.")
               (base32
                "00ilv65dzcgiap435j89xk86shf7rrav3wsik7cahy789qijdcn9"))))
     (build-system gnu-build-system)
-    (inputs `(("util-linux" ,util-linux)))
+    ;; Arrange so that 'mke2fs' doesn't wait: <https://bugs.gnu.org/31268>.
+    (inputs `(("util-linux" ,util-linux/libuuid-non-blocking-random)))
     (native-inputs `(("pkg-config" ,pkg-config)
                      ("texinfo" ,texinfo)       ;for the libext2fs Info manual
 
diff --git a/gnu/packages/patches/util-linux-libuuid-non-blocking-random.patch b/gnu/packages/patches/util-linux-libuuid-non-blocking-random.patch
new file mode 100644
index 000000000..c0b3ea24d
--- /dev/null
+++ b/gnu/packages/patches/util-linux-libuuid-non-blocking-random.patch
@@ -0,0 +1,15 @@
+Change libuuid so that 'uuid_generate' is non-blocking.  This is needed when
+'mke2fs' is used during early boot in VMs with little entropy available.
+See <https://bugs.gnu.org/31268>.
+
+--- a/lib/randutils.c
++++ b/lib/randutils.c
+@@ -104,7 +104,7 @@ void random_get_bytes(void *buf, size_t nbytes)
+ 		int x;
+ 
+ 		errno = 0;
+-		x = getrandom(cp, n, 0);
++		x = getrandom(cp, n, GRND_NONBLOCK);
+ 		if (x > 0) {			/* success */
+ 		       n -= x;
+ 		       cp += x;
-- 
2.17.0