From b66396df80cda9f16db3ffe18bfd57d4f54de278 Mon Sep 17 00:00:00 2001
From: Steffen Maier <maier@linux.ibm.com>
Date: Fri, 12 May 2023 13:57:55 +0200
Subject: [PATCH] zdev: add helper to convert from zdev config to dasd_mod.dasd

Converts zdev configuration into the syntax of the kernel module parameter
dasd_mod.dasd. Only DASD options with non-default values are emitted. The
result string occurs on stdout. It represents one device-specification for
the given DASD device bus-ID.

Example:
/lib/s390-tools/zdev-to-dasd_mod.dasd persistent 0.0.da5d
0.0.da5d(erplog)

User:
https://github.com/storaged-project/blivet/pull/1162
to generate dracut cmdline entries such as rd.dasd=0.0.da5d(erplog)

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
---
 zdev/src/Makefile              |  3 ++-
 zdev/src/zdev-to-dasd_mod.dasd | 37 ++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100755 zdev/src/zdev-to-dasd_mod.dasd

diff --git a/zdev/src/Makefile b/zdev/src/Makefile
index 281201e6..c43b6547 100644
--- a/zdev/src/Makefile
+++ b/zdev/src/Makefile
@@ -106,11 +106,12 @@ libs =	$(rootdir)/libap/libap.a \
 chzdev: $(chzdev_objects) $(libs)
 lszdev: $(lszdev_objects) $(libs)
 
-install: chzdev zdev_id
+install: chzdev zdev_id zdev-to-dasd_mod.dasd
 	$(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)
 ifeq ($(HAVE_DRACUT),1)
 	$(INSTALL) -m 755 zdev-root-update.dracut \
 		$(DESTDIR)$(TOOLS_LIBDIR)/zdev-root-update
diff --git a/zdev/src/zdev-to-dasd_mod.dasd b/zdev/src/zdev-to-dasd_mod.dasd
new file mode 100755
index 00000000..f9f11026
--- /dev/null
+++ b/zdev/src/zdev-to-dasd_mod.dasd
@@ -0,0 +1,37 @@
+#!/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-dasd_mod.dasd
+#   Converts zdev configuration into the syntax of the kernel module parameter
+#   dasd_mod.dasd. Only DASD options with non-default values are emitted. The
+#   result string occurs on stdout. It represents one device-specification for
+#   the given DASD device bus-ID.
+#
+
+function usage() {
+    echo "usage: ${0##*/} active|persistent <DASD device bus-ID>" 1>&2
+    exit 1
+}
+
+[[ $# -eq 2 ]] || usage
+
+[[ "$1" == active ]] || [[ "$1" == persistent ]] || usage
+
+_selection="--${1}"
+_busid="$2"
+
+while read -r _line; do
+    case "$_line" in
+        "readonly=1") _attrs="${_attrs:+${_attrs}:}ro" ;;
+        "use_diag=1") _attrs="${_attrs:+${_attrs}:}diag" ;;
+        "raw_track_access=1") _attrs="${_attrs:+${_attrs}:}raw" ;;
+        "erplog=1") _attrs="${_attrs:+${_attrs}:}erplog" ;;
+        "failfast=1") _attrs="${_attrs:+${_attrs}:}failfast" ;;
+    esac
+done < <(chzdev dasd "$_busid" "$_selection" --export - --quiet)
+[[ -n "$_attrs" ]] && _attrs="($_attrs)"
+printf "%s%s\n" "$_busid" "$_attrs"