[LEDE-DEV] [PATCH 01/12] opkg: add update-alternatives support

[Yousong Zhou]

Signed-off-by: Yousong Zhou <yszhou4tech at gmail.com>
---
 package/system/opkg/Makefile                  |   5 +-
 package/system/opkg/files/update-alternatives | 163 ++++++++++++++++++++++++++
 2 files changed, 167 insertions(+), 1 deletion(-)
 create mode 100755 package/system/opkg/files/update-alternatives

diff --git a/package/system/opkg/Makefile b/package/system/opkg/Makefile
index fbf87cb..56f5cce 100644
--- a/package/system/opkg/Makefile
+++ b/package/system/opkg/Makefile
@@ -11,7 +11,7 @@ include $(INCLUDE_DIR)/version.mk
 include $(INCLUDE_DIR)/feeds.mk
 
 PKG_NAME:=opkg
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 PKG_FLAGS:=essential
 
 PKG_SOURCE_PROTO:=git
@@ -94,6 +94,9 @@ define Package/opkg/install
   endif
 	$(INSTALL_DIR) $(1)/usr/sbin
 	$(INSTALL_BIN) ./files/opkg-key $(1)/usr/sbin/
+	$(INSTALL_BIN) ./files/update-alternatives $(1)/usr/sbin/
+	$(INSTALL_DIR) $(1)/etc/config
+	touch $(1)/etc/config/opkg
 endef
 
 define Host/Install
diff --git a/package/system/opkg/files/update-alternatives b/package/system/opkg/files/update-alternatives
new file mode 100755
index 0000000..6a8f18b
--- /dev/null
+++ b/package/system/opkg/files/update-alternatives
@@ -0,0 +1,163 @@
+#!/bin/sh
+
+usage() {
+	cat <<EOF
+Usage: $0 update|remove --spec <prio>:<path>:<alt-path>
+
+EOF
+	exit 1
+}
+
+errmsg() {
+	echo "$0: $@" >&2
+}
+
+uci_() {
+	$UCI ${UCI_CONFIG_DIR:+-c $UCI_CONFIG_DIR} "$@"
+}
+
+check_path() {
+	local path="${IPKG_INSTROOT}$1"
+
+	[ -L "$path" -o ! -e "$path" ] || {
+		errmsg "$0: $path exists and is not an symbolic file"
+		exit 1
+	}
+}
+
+update_path() {
+	local path="$1"
+	local found_section found_altpath
+	local found_prio=-1 found_prio_altpath
+	local IFS cur altpath
+
+	config_load opkg
+	config_foreach find_path alternatives "$prio" "$path"
+	if [ -n "$found_prio_altpath" ]; then
+		IFS=:; set -- $found_prio_altpath; altpath=$2; IFS="$oIFS"
+		cur="$(readlink -f "$path")"
+		if [ "$cur" != "$altpath" ]; then
+			errmsg "link $path -> $altpath"
+			ln -sf "$altpath" "${IPKG_INSTROOT}$path"
+		fi
+	elif [ -n "$found_section" ]; then
+		errmsg "remove empty alternatives section for $path"
+		uci_ delete "opkg.$found_section"
+		uci_ commit opkg
+		rm -f "${IPKG_INSTROOT}$path"
+	fi
+}
+
+find_altpath() {
+	local cfgaltpath="$1"
+	local cfg="$2"
+	local prio="$3"
+	local altpath="$4"
+	local cfgprio cfgaltpath_
+	local oIFS="$IFS"; IFS=:; set -- $cfgaltpath; cfgprio="$1"; cfgaltpath_="$2"; IFS="$oIFS"
+
+	if [ "$cfgaltpath_" = "$altpath" ]; then
+		found_altpath="$cfgaltpath"
+	fi
+	if [ "$cfgprio" -gt "$found_prio" ]; then
+		found_prio="$cfgprio"
+		found_prio_altpath="$cfgaltpath"
+	fi
+}
+
+find_path() {
+	local cfg="$1"
+	local prio="$2"
+	local path="$3"
+	local altpath="$4"
+	local cfgpath
+
+	config_get cfgpath "$cfg" path
+	[ "$cfgpath" = "$path" ] || return
+	found_section="$cfg"
+	config_list_foreach "$cfg" altpath find_altpath "$cfg" "$prio" "$altpath"
+}
+
+cmd_update() {
+	local spec="$1"
+	local prio path altpath
+	local oIFS="$IFS"
+	local found_section found_altpath
+	local found_prio=-1 found_prio_altpath
+
+	IFS=:; set -- $spec; IFS="$oIFS"
+	prio="$1"
+	path="$2"
+	altpath="$3"
+	check_path "$path"
+	if [ ! -e "${IPKG_INSTROOT}$altpath" ]; then
+		errmsg "$altpath does not exist"
+		return 1
+	fi
+
+	config_load opkg
+	config_foreach find_path alternatives "$prio" "$path" "$altpath"
+	if [ -z "$found_section" ]; then
+		found_section="$(uci_ add opkg alternatives)"
+		uci_ set opkg.$found_section.path=$path
+	fi
+	if [ -n "$found_altpath" ]; then
+		if [ "$found_altpath" != "$prio:$altpath" ]; then
+			# update priority
+			uci_ del_list opkg.$found_section.altpath=$found_altpath
+			uci_ add_list opkg.$found_section.altpath=$prio:$altpath
+		fi
+	else
+		uci_ add_list opkg.$found_section.altpath=$prio:$altpath
+	fi
+	uci_ commit opkg
+	update_path "$path"
+}
+
+cmd_remove() {
+	local spec="$1"
+	local prio path altpath
+	local oIFS="$IFS"
+	local found_section found_altpath
+	local found_prio=-1 found_prio_altpath
+
+	IFS=:; set -- $spec; IFS="$oIFS"
+	prio="$1"
+	path="$2"
+	altpath="$3"
+	check_path "$path"
+
+	config_load opkg
+	config_foreach find_path alternatives "$prio" "$path" "$altpath"
+	if [ -n "$found_section" -a -n "$found_altpath" ]; then
+		uci_ del_list opkg.$found_section.altpath=$found_altpath
+		uci_ commit opkg
+		update_path "$path"
+	else
+		errmsg "spec $spec not found"
+	fi
+}
+
+. ${IPKG_INSTROOT}/lib/functions.sh
+
+UCI="${UCI:-/sbin/uci}"
+UCI_STATE_DIR="${IPKG_INSTROOT}/var/state"
+ARG_CMD=
+ARG_SPEC=
+while [ "$#" -gt 0 ]; do
+	case "$1" in
+		update|remove)
+			ARG_CMD="$1"
+			shift
+			;;
+		--spec)
+			ARG_SPEC="$2";
+			shift 2
+			;;
+		*) usage ;;
+	esac
+done
+
+[ -n "$ARG_CMD" -a -n "$ARG_SPEC" ] || usage
+
+cmd_$ARG_CMD "$ARG_SPEC"
-- 
2.6.4