From e427f53b8fa4ddb43d9f21828aa56680348d3dae Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Fri, 9 Jul 2021 08:18:57 +0200
Subject: [PATCH] glib-aux: add getrandom() syscall wrapper as fallback

We make an effort to get a better fallback case with
_bad_random_bytes().

Also make an effort to get good randomness in the first place. Even if
we compile against libc headers that don't provide getrandom(). Also,
this isn't really ugly, because for a long time glibc was reluctant to
add getrandom() wrapper and using syscall() was the way to go.

(cherry picked from commit 05a6936befed8806d42a988b777d3013f15f6683)
---
 src/libnm-glib-aux/nm-random-utils.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/src/libnm-glib-aux/nm-random-utils.c b/src/libnm-glib-aux/nm-random-utils.c
index aaeec62cc1..e8fc47e109 100644
--- a/src/libnm-glib-aux/nm-random-utils.c
+++ b/src/libnm-glib-aux/nm-random-utils.c
@@ -9,6 +9,7 @@
 
 #include <fcntl.h>
 #include <sys/auxv.h>
+#include <sys/syscall.h>
 
 #if USE_SYS_RANDOM_H
     #include <sys/random.h>
@@ -21,6 +22,26 @@
 
 /*****************************************************************************/
 
+#if !defined(SYS_getrandom) && defined(__NR_getrandom)
+    #define SYS_getrandom __NR_getrandom
+#endif
+
+#ifndef GRND_NONBLOCK
+    #define GRND_NONBLOCK 0x01
+#endif
+
+#if !HAVE_GETRANDOM && defined(SYS_getrandom)
+static int
+getrandom(void *buf, size_t buflen, unsigned flags)
+{
+    return syscall(SYS_getrandom, buf, buflen, flags);
+}
+    #undef HAVE_GETRANDOM
+    #define HAVE_GETRANDOM 1
+#endif
+
+/*****************************************************************************/
+
 #define STATIC_SALT "l6z5vMBldDlCD6na"
 
 typedef struct _nm_packed {