fix issue chroot, rpm -qa error: Failed to initialize NSS library xca…

…t2#4959

xCAT-server/share/xcat/netboot/rh/genimage

@@ -520,7 +520,7 @@ unless ($onlyinitrd) {
         # Hack uname when deal otherpkgs
         use_hackuname($arch, $kernelver);
         use_devnull();
-
+        use_devurandom();
 
         foreach $pass (sort { $a <=> $b } (keys(%extra_hash))) {
             $yumcmd = $yumcmd_base;
@@ -2355,6 +2355,18 @@ sub use_devnull {
     }
 }
 
+#in rhels7.5, the /dev/urandom does not exist in rootimg directory
+#which cause any rpm command fail with `error: Failed to initialize NSS library`
+#create urandom in genimage to avoid the error
+sub use_devurandom {
+    if (-e "$rootimg_dir/dev/urandom" and !-c "$rootimg_dir/dev/urandom") {
+        system("rm -f $rootimg_dir/dev/urandom");
+    }
+    if (!-e "$rootimg_dir/dev/urandom") {
+        system("mknod -m444 $rootimg_dir/dev/urandom c 1 9");
+    }
+}
+
 # Hack uname functions to match what's installed in the rootimg
 # instead of what's running on the management node.
 # Needed for some RPMs, especially kernel modules via DKMS.