From 6045b1b8a0d8ed6a94d06cdfc994bf1a5fa9dbb5 Mon Sep 17 00:00:00 2001
From: Jim Gauld <james.gauld@windriver.com>
Date: Thu, 6 May 2021 11:58:34 -0400
Subject: [PATCH] Provide utility script is-rootdisk-device.sh

This provides a utility script to determine which disk contains the root
filesystem. This can also be used as a helper function for io-scheduler
udev rules that require specific configuration for root disk.

Example usage:
/usr/local/bin/is-rootdisk-device.sh
ROOTDISK_DEVICE=sda

/usr/local/bin/is-rootdisk-device.sh /dev/sda
ROOTDISK_DEVICE=sda

/usr/local/bin/is-rootdisk-device.sh /dev/sdb
(i.e., no output)

Partial-Bug: 1927515
Signed-off-by: Jim Gauld <james.gauld@windriver.com>
Change-Id: Ib0d4a161a407b08d294c5ff9aa0b7590961e18c9
---
 .../platform-util/centos/platform-util.spec   |  2 ++
 .../scripts/is-rootdisk-device.sh             | 28 +++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100755 utilities/platform-util/scripts/is-rootdisk-device.sh

diff --git a/utilities/platform-util/centos/platform-util.spec b/utilities/platform-util/centos/platform-util.spec
index 124d39f9..55dc7761 100644
--- a/utilities/platform-util/centos/platform-util.spec
+++ b/utilities/platform-util/centos/platform-util.spec
@@ -60,6 +60,7 @@ install -d %{buildroot}%{local_bindir}
 install %{_buildsubdir}/scripts/tc_setup.sh %{buildroot}%{local_bindir}
 install %{_buildsubdir}/scripts/remotelogging_tc_setup.sh %{buildroot}%{local_bindir}
 install %{_buildsubdir}/scripts/connectivity_test %{buildroot}%{local_bindir}
+install -m 555 %{_buildsubdir}/scripts/is-rootdisk-device.sh %{buildroot}%{local_bindir}
 install -m 555 %{_buildsubdir}/scripts/update-iso.sh %{buildroot}%{local_bindir}
 install -m 555 %{_buildsubdir}/scripts/gen-bootloader-iso.sh %{buildroot}%{local_bindir}
 install -m 555 %{_buildsubdir}/scripts/stx-iso-utils.sh %{buildroot}%{local_bindir}
@@ -95,6 +96,7 @@ systemctl enable opt-platform.service
 %{local_bindir}/tc_setup.sh
 %{local_bindir}/remotelogging_tc_setup.sh
 %{local_bindir}/connectivity_test
+%{local_bindir}/is-rootdisk-device.sh
 %{local_bindir}/set_keystone_user_option.sh
 %{local_sbindir}/patch-restart-mtce
 %{local_sbindir}/patch-restart-processes
diff --git a/utilities/platform-util/scripts/is-rootdisk-device.sh b/utilities/platform-util/scripts/is-rootdisk-device.sh
new file mode 100755
index 00000000..69cb4628
--- /dev/null
+++ b/utilities/platform-util/scripts/is-rootdisk-device.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+#
+# Copyright (c) 2021 Wind River Systems, Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Usage:
+#   is-rootdisk-device <device>
+#
+# If no arguments are provided, this shows which disk contains the
+# root filesystem. If the optional device parameter is specified,
+# output is only generated when the device matches the root disk.
+
+dev=$1
+
+rootdev=$(lsblk --ascii -oPKNAME -n $(findmnt -n -T / -o SOURCE))
+if [ $# -eq 0 ]; then
+    echo "ROOTDISK_DEVICE=${rootdev}"
+else
+    if [ "${dev}" == "/dev/${rootdev}" ] || \
+        [ "/dev/${dev}" == "/dev/${rootdev}" ]; then
+        echo "ROOTDISK_DEVICE=${rootdev}"
+    else
+        exit 1
+    fi
+fi
+
+exit 0