[PATCH v4 04/13] add a helper function to read kernel cmdline parameter from grubby --info

[Coiby Xu]

This helper function will be used to retrieve the value of kernel
cmdline parameters including crashkernel, fadump, swiotlb and etc.

Suggested-by: Philipp Rudo <prudo(a)redhat.com&gt;
Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
---
 kdumpctl | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/kdumpctl b/kdumpctl
index 9ec3f10f..f4ff457a 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -1306,6 +1306,17 @@ get_default_crashkernel()
 	kdump_get_arch_recommend_crashkernel "$_dump_mode"
 }
 
+# Read kernel cmdline parameter for a specific kernel
+# $1: kernel path, DEFAULT or kernel path, ALL not accepted
+# $2: kernel cmldine parameter
+get_grub_kernel_boot_parameter()
+{
+	local _kernel_path=$1 _para=$2
+
+	[[ $_kernel_path == ALL ]] && derror "kernel_path=ALL invalid for
get_grub_kernel_boot_parameter" && return 1
+	grubby --info="$_kernel_path" | sed -En -e
"/^args=.*$/{s/^.*(\s|\")${_para}=(\S*).*\"$/\2/p;q}"
+}
+
 reset_crashkernel()
 {
 	local kernel=$1 entry crashkernel_default
-- 
2.31.1