From 9a8bfee954f9acb2b27116abbc3b8f57c74a73b7 Mon Sep 17 00:00:00 2001
From: Darshaka Pathirana <dpat@syn-net.org>
Date: Sat, 2 Mar 2019 02:22:12 +0100
Subject: [PATCH] Add DHCP setting for Predictable Network Interface Names

Predictable Network Interface Names were missing the default
/etc/network/interfaces file when using the --defaultinterfaces option.

Added a Networking-Section in the man page to clarify how the network is
configured in the target system and fixed the documentation for the
options --vmfile and --vm. Both options automatically enable the
--defaultinterface option and not the --nointerfaces option.

Closes: grml/grml-debootstrap#126
---
 grml-debootstrap       | 10 ++++++++++
 grml-debootstrap.8.txt | 15 +++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/grml-debootstrap b/grml-debootstrap
index 18954a9..016daec 100755
--- a/grml-debootstrap
+++ b/grml-debootstrap
@@ -1723,6 +1723,16 @@ allow-hotplug eth0
 iface eth0 inet dhcp
 "
 
+  # add dhcp setting for Predictable Network Interface Names
+  if [ -x /bin/udevadm ]; then
+    for interface in $(udevadm info -e | sed -n -e 's/E: ID_NET_NAME_PATH=\([^$*]\)/\1/p'); do
+      DEFAULT_INTERFACES="${DEFAULT_INTERFACES}
+allow-hotplug ${interface}
+iface ${interface} inet dhcp
+"
+    done
+  fi
+
   if [ -n "$NOINTERFACES" ] ; then
     einfo "Not installing /etc/network/interfaces as requested via --nointerfaces option" ; eend 0
   elif [ -n "$USE_DEFAULT_INTERFACES" ] ; then
diff --git a/grml-debootstrap.8.txt b/grml-debootstrap.8.txt
index 276b968..9c6d2d6 100644
--- a/grml-debootstrap.8.txt
+++ b/grml-debootstrap.8.txt
@@ -85,8 +85,11 @@ Options and environment variables
 
 *--defaultinterfaces*::
 
-   Install a default /etc/network/interfaces file (enabling DHCP for eth0)
+   Install a default /etc/network/interfaces file (enabling DHCP for all local
+   Ethernet, WLAN and WWAN interfaces using predictable network interface names
+   and using eth0 as tradtition interface name for backward compatibility)
    instead of taking over config from host system.
+   This option is automatically enabled when using --vm or --vmfile.
 
 *--efi* _device_::
 
@@ -155,7 +158,6 @@ Options and environment variables
 *--nointerfaces*::
 
     Do not copy /etc/network/interfaces from host system to the target.
-    This option is automatically enabled when using --vm or --vmfile.
 
 *--nokernel*::
 
@@ -239,6 +241,7 @@ Options and environment variables
     partitioned.
     This allows deployment of a Virtual Machine. The options needs to be
     combined with the --target option.
+    This option automatically enables the --defaultinterfaces option.
     Usage example: --vm --target /dev/mapper/your-vm-disk
 
 *--vmfile*::
@@ -247,6 +250,7 @@ Options and environment variables
     partition/block device or directory. This allows deployment of a Virtual
     Machine. The options needs to be combined with the --target option
     ('qemu-img create -f raw ...' is executed on the specified target).
+    This option automatically enables the --defaultinterfaces option.
     Usage example: --vmfile --target /mnt/sda1/qemu.img
 
 *--vmsize* _size_::
@@ -264,6 +268,13 @@ WARNING: the command line parsing of grml-debootstrap usually does not validate
 the provided arguments for the command line options. Please be careful and check
 docs and /etc/debootstrap/config for further information.
 
+Networking
+----------
+
+By default (that is, if none of the options *--nointerfaces*,
+*--defaultinterfaces*, *--vmfile* or *--vm* are given) /etc/network/interfaces
+will be copied from the host to the target system.
+
 Usage examples
 ---------------
 
-- 
2.1.4