[PATCH v1 1/4] scripts/config: import Kconfig manipulation tool from Linux

[dmukhin@xxxxxxx]

From: Denis Mukhin <dmukhin@xxxxxxxx> 

Manipulating Kconfig settings is often required when preparing a custom
Xen build using an external build system (e.g., a Yocto-based workflow).

Import the Kconfig manipulation tool from the Linux kernel
(commit 0f61b1860cc3, Linux v6.19-rc5) to support this use case.

Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
 xen/scripts/config | 236 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 236 insertions(+)
 create mode 100755 xen/scripts/config

diff --git a/xen/scripts/config b/xen/scripts/config
new file mode 100755
index 000000000000..ea475c07de28
--- /dev/null
+++ b/xen/scripts/config
@@ -0,0 +1,236 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0
+# Manipulate options in a .config file from the command line
+
+myname=${0##*/}
+
+# If no prefix forced, use the default CONFIG_
+CONFIG_="${CONFIG_-CONFIG_}"
+
+# We use an uncommon delimiter for sed substitutions
+SED_DELIM=$(echo -en "\001")
+
+usage() {
+       cat >&2 <<EOL
+Manipulate options in a .config file from the command line.
+Usage:
+$myname options command ...
+commands:
+       --enable|-e option   Enable option
+       --disable|-d option  Disable option
+       --module|-m option   Turn option into a module
+       --set-str option string
+                            Set option to "string"
+       --set-val option value
+                            Set option to value
+       --undefine|-u option Undefine option
+       --state|-s option    Print state of option (n,y,m,undef)
+
+       --enable-after|-E beforeopt option
+                             Enable option directly after other option
+       --disable-after|-D beforeopt option
+                             Disable option directly after other option
+       --module-after|-M beforeopt option
+                             Turn option into module directly after other 
option
+       --refresh            Refresh the config using old settings
+
+       commands can be repeated multiple times
+
+options:
+       --file config-file   .config file to change (default .config)
+       --keep-case|-k       Keep next symbols' case (dont' upper-case it)
+
+$myname doesn't check the validity of the .config file. This is done at next
+make time.
+
+By default, $myname will upper-case the given symbol. Use --keep-case to keep
+the case of all following symbols unchanged.
+
+$myname uses 'CONFIG_' as the default symbol prefix. Set the environment
+variable CONFIG_ to the prefix to use. Eg.: CONFIG_="FOO_" $myname ...
+EOL
+       exit 1
+}
+
+checkarg() {
+       ARG="$1"
+       if [ "$ARG" = "" ] ; then
+               usage
+       fi
+       case "$ARG" in
+       ${CONFIG_}*)
+               ARG="${ARG/${CONFIG_}/}"
+               ;;
+       esac
+       if [ "$MUNGE_CASE" = "yes" ] ; then
+               ARG="`echo $ARG | tr a-z A-Z`"
+       fi
+}
+
+txt_append() {
+       local anchor="$1"
+       local insert="$2"
+       local infile="$3"
+       local tmpfile="$infile.swp"
+
+       # sed append cmd: 'a\' + newline + text + newline
+       cmd="$(printf "a\\%b$insert" "\n")"
+
+       sed -e "/$anchor/$cmd" "$infile" >"$tmpfile"
+       # replace original file with the edited one
+       mv "$tmpfile" "$infile"
+}
+
+txt_subst() {
+       local before="$1"
+       local after="$2"
+       local infile="$3"
+       local tmpfile="$infile.swp"
+
+       sed -e "s$SED_DELIM$before$SED_DELIM$after$SED_DELIM" "$infile" 
>"$tmpfile"
+       # replace original file with the edited one
+       mv "$tmpfile" "$infile"
+}
+
+txt_delete() {
+       local text="$1"
+       local infile="$2"
+       local tmpfile="$infile.swp"
+
+       sed -e "/$text/d" "$infile" >"$tmpfile"
+       # replace original file with the edited one
+       mv "$tmpfile" "$infile"
+}
+
+set_var() {
+       local name=$1 new=$2 before=$3
+
+       name_re="^($name=|# $name is not set)"
+       before_re="^($before=|# $before is not set)"
+       if test -n "$before" && grep -Eq "$before_re" "$FN"; then
+               txt_append "^$before=" "$new" "$FN"
+               txt_append "^# $before is not set" "$new" "$FN"
+       elif grep -Eq "$name_re" "$FN"; then
+               txt_subst "^$name=.*" "$new" "$FN"
+               txt_subst "^# $name is not set" "$new" "$FN"
+       else
+               echo "$new" >>"$FN"
+       fi
+}
+
+undef_var() {
+       local name=$1
+
+       txt_delete "^$name=" "$FN"
+       txt_delete "^# $name is not set" "$FN"
+}
+
+FN=.config
+CMDS=()
+while [[ $# -gt 0 ]]; do
+       if [ "$1" = "--file" ]; then
+               if [ "$2" = "" ]; then
+                       usage
+               fi
+               FN="$2"
+               shift 2
+       else
+               CMDS+=("$1")
+               shift
+       fi
+done
+
+set -- "${CMDS[@]}"
+if [ "$1" = "" ] ; then
+       usage
+fi
+
+MUNGE_CASE=yes
+while [ "$1" != "" ] ; do
+       CMD="$1"
+       shift
+       case "$CMD" in
+       --keep-case|-k)
+               MUNGE_CASE=no
+               continue
+               ;;
+       --refresh)
+               ;;
+       --*-after|-E|-D|-M)
+               checkarg "$1"
+               A=$ARG
+               checkarg "$2"
+               B=$ARG
+               shift 2
+               ;;
+       -*)
+               checkarg "$1"
+               shift
+               ;;
+       esac
+       case "$CMD" in
+       --enable|-e)
+               set_var "${CONFIG_}$ARG" "${CONFIG_}$ARG=y"
+               ;;
+
+       --disable|-d)
+               set_var "${CONFIG_}$ARG" "# ${CONFIG_}$ARG is not set"
+               ;;
+
+       --module|-m)
+               set_var "${CONFIG_}$ARG" "${CONFIG_}$ARG=m"
+               ;;
+
+       --set-str)
+               # sed swallows one level of escaping, so we need double-escaping
+               set_var "${CONFIG_}$ARG" "${CONFIG_}$ARG=\"${1//\"/\\\\\"}\""
+               shift
+               ;;
+
+       --set-val)
+               set_var "${CONFIG_}$ARG" "${CONFIG_}$ARG=$1"
+               shift
+               ;;
+       --undefine|-u)
+               undef_var "${CONFIG_}$ARG"
+               ;;
+
+       --state|-s)
+               if grep -q "# ${CONFIG_}$ARG is not set" $FN ; then
+                       echo n
+               else
+                       V="$(grep "^${CONFIG_}$ARG=" $FN)"
+                       if [ $? != 0 ] ; then
+                               echo undef
+                       else
+                               V="${V/#${CONFIG_}$ARG=/}"
+                               V="${V/#\"/}"
+                               V="${V/%\"/}"
+                               V="${V//\\\"/\"}"
+                               echo "${V}"
+                       fi
+               fi
+               ;;
+
+       --enable-after|-E)
+               set_var "${CONFIG_}$B" "${CONFIG_}$B=y" "${CONFIG_}$A"
+               ;;
+
+       --disable-after|-D)
+               set_var "${CONFIG_}$B" "# ${CONFIG_}$B is not set" 
"${CONFIG_}$A"
+               ;;
+
+       --module-after|-M)
+               set_var "${CONFIG_}$B" "${CONFIG_}$B=m" "${CONFIG_}$A"
+               ;;
+
+       --refresh)
+               yes "" | make oldconfig KCONFIG_CONFIG=$FN
+               ;;
+
+       *)
+               echo "bad command: $CMD" >&2
+               usage
+               ;;
+       esac
+done
-- 
2.52.0