From 73f51e45a8c41df2db524a728fd865d555d02489 Mon Sep 17 00:00:00 2001
From: Steffen Maier <maier@linux.ibm.com>
Date: Wed, 6 Sep 2023 19:01:59 +0200
Subject: [PATCH] zdev: add helper to convert from zdev config to rd.znet
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Converts zdev configuration into the syntax of the dracut cmdline option
rd.znet. Only znet options with non-default values are emitted. The result
string occurs on stdout. It represents one device-specification for the
given network interface name.

Example:
/lib/s390-tools/zdev-to-rd.znet persistent encbdf0
qeth,0.0.bdf0,0.0.bdf1,0.0.bdf2,layer2=1

User:
https://github.com/rhinstaller/anaconda/pull/5250
to generate dracut cmdline entries such as
rd.znet=qeth,0.0.bdf0,0.0.bdf1,0.0.bdf2,layer2=1

Github-ID: https://github.com/ibm-s390-linux/s390-tools/pull/158
Acked-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
---
 zdev/src/Makefile        |  4 +++-
 zdev/src/zdev-to-rd.znet | 49 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100755 zdev/src/zdev-to-rd.znet

diff --git a/zdev/src/Makefile b/zdev/src/Makefile
index 54785378..f90f73e8 100644
--- a/zdev/src/Makefile
+++ b/zdev/src/Makefile
@@ -106,13 +106,15 @@ libs =	$(rootdir)/libap/libap.a \
 chzdev: $(chzdev_objects) $(libs)
 lszdev: $(lszdev_objects) $(libs)
 
-install: chzdev zdev_id zdev-to-dasd_mod.dasd zdev-from-dasd_mod.dasd
+install: chzdev zdev_id zdev-to-dasd_mod.dasd zdev-from-dasd_mod.dasd \
+	zdev-to-rd.znet
 	$(INSTALL) -d -m 755 $(DESTDIR)$(BINDIR)
 	$(INSTALL) -c chzdev $(DESTDIR)$(BINDIR)
 	$(INSTALL) -c lszdev $(DESTDIR)$(BINDIR)
 	$(INSTALL) -c zdev_id $(DESTDIR)$(TOOLS_LIBDIR)
 	$(INSTALL) -c zdev-to-dasd_mod.dasd $(DESTDIR)$(TOOLS_LIBDIR)
 	$(INSTALL) -c -m 644 zdev-from-dasd_mod.dasd $(DESTDIR)$(TOOLS_LIBDIR)
+	$(INSTALL) -c zdev-to-rd.znet $(DESTDIR)$(TOOLS_LIBDIR)
 ifeq ($(HAVE_DRACUT),1)
 	$(INSTALL) -m 755 zdev-root-update.dracut \
 		$(DESTDIR)$(TOOLS_LIBDIR)/zdev-root-update
diff --git a/zdev/src/zdev-to-rd.znet b/zdev/src/zdev-to-rd.znet
new file mode 100755
index 00000000..2dc71670
--- /dev/null
+++ b/zdev/src/zdev-to-rd.znet
@@ -0,0 +1,49 @@
+#!/bin/bash
+#
+# Copyright IBM Corp. 2023
+#
+# s390-tools is free software; you can redistribute it and/or modify
+# it under the terms of the MIT license. See LICENSE for details.
+#
+# zdev-to-rd.znet
+#   Converts zdev configuration into the syntax of the dracut cmdline option
+#   rd.znet. Only znet options with non-default values are emitted. The
+#   result string occurs on stdout. It represents one device-specification for
+#   the given network interface name.
+#
+
+function usage() {
+    echo "usage: ${0##*/} active|persistent <network interface name>" 1>&2
+    exit 1
+}
+
+[[ $# -eq 2 ]] || usage
+
+[[ "$1" == active ]] || [[ "$1" == persistent ]] || usage
+
+_selection="--${1}"
+_ifname="$2"
+
+while read -r _line; do
+    case "$_line" in
+        \#*) ;;
+        \[*)
+            SAVED_IFS="$IFS"
+            IFS="${IFS}:]"
+            # shellcheck disable=SC2086
+            set -- $_line
+            shift # skip "[..." prefix
+            _nettype="$1"
+            shift # skip nettype
+            IFS="," # comma-separated subchannel list
+            _subchannels="$*"
+            IFS="$SAVED_IFS"
+            ;;
+        "online=1") ;;
+        zdev:early=*) ;;
+        *)
+            _attrs="${_attrs},${_line}"
+            ;;
+    esac
+done < <(chzdev --by-interface "$_ifname" "$_selection" --export - --quiet)
+printf "%s,%s%s\n" "$_nettype" "$_subchannels" "$_attrs"