installer.sh: add post-installation menu for enabling services

chose to do it *post* install, just before syncing and unmounting,
because it's the easiest place to know exactly what services will be
available and which will be enabled in the target system in the mess
that is the el-cheapo installer.

filters out some important services that users shouldn't be messing with
at this point in the install, like some agettys, udevd, and sulogin.

installer.sh

@@ -50,6 +50,7 @@ if [ ! -f $CONF_FILE ]; then
     touch -f $CONF_FILE
 fi
 ANSWER=$(mktemp -t vinstall-XXXXXXXX || exit 1)
+TARGET_SERVICES=$(mktemp -t vinstall-sv-XXXXXXXX || exit 1)
 TARGET_FSTAB=$(mktemp -t vinstall-fstab-XXXXXXXX || exit 1)
 
 trap "DIE" INT TERM QUIT
@@ -112,7 +113,7 @@ DIE() {
     rval=$1
     [ -z "$rval" ] && rval=0
     clear
-    rm -f $ANSWER $TARGET_FSTAB
+    rm -f $ANSWER $TARGET_FSTAB $TARGET_SERVICES
     # reenable printk
     if [ -w /proc/sys/kernel/printk ]; then
         echo 4 >/proc/sys/kernel/printk
@@ -1261,8 +1262,44 @@ install_packages() {
     fi
 }
 
+menu_services() {
+    local sv _status _checklist=""
+    find $TARGETDIR/etc/runit/runsvdir/default -mindepth 1 -maxdepth 1 -xtype d -printf '%f\n' | sort -u > "$TARGET_SERVICES"
+    while true; do
+        while read -r sv; do
+            if [ -n "$sv" ]; then
+                if grep -qx "$sv" "$TARGET_SERVICES" 2>/dev/null; then
+                    _status=on
+                else
+                    _status=off
+                fi
+                _checklist+=" ${sv} ${sv} ${_status}"
+            fi
+        done < <(find $TARGETDIR/etc/sv -mindepth 1 -maxdepth 1 -type d -printf '%f\n' | \
+            # filter out services that probably shouldn't be messed with
+            grep -Ev '^(agetty-(tty[1-9]|generic|serial)|udevd|sulogin)$' | sort -u)
+        echo "$_checklist" 1>&2
+        DIALOG --no-tags --checklist "Select services to enable:" 20 60 18 ${_checklist}
+        if [ $? -eq 0 ]; then
+            comm -13 "$TARGET_SERVICES" <(tr ' ' '\n' "$ANSWER") | while read -r sv; do
+                enable_service "$sv"
+            done
+            comm -23 "$TARGET_SERVICES" <(tr ' ' '\n' "$ANSWER") | while read -r sv; do
+                disable_service "$sv"
+            done
+            break
+        else
+            return
+        fi
+    done
+}
+
 enable_service() {
-    ln -sf /etc/sv/$1 $TARGETDIR/etc/runit/runsvdir/default/$1
+    ln -sf "/etc/sv/$1" "$TARGETDIR/etc/runit/runsvdir/default/$1"
+}
+
+disable_service() {
+    rm -f "$TARGETDIR/etc/runit/runsvdir/default/$1"
 }
 
 menu_install() {
@@ -1386,7 +1423,7 @@ ${BOLD}Do you want to continue?${RESET}" 20 80 || return
         elif [ "$_type" = "dhcp" ]; then
             if $(echo $_dev|egrep -q "^wl.*" 2>/dev/null); then
                 cp /etc/wpa_supplicant/wpa_supplicant.conf $TARGETDIR/etc/wpa_supplicant
-                ln -sf /etc/sv/wpa_supplicant $TARGETDIR/etc/runit/runsvdir/default/wpa_supplicant
+                enable_service wpa_supplicant
             fi
             enable_service dhcpcd
         elif [ -n "$_dev" -a "$_type" = "static" ]; then
@@ -1427,6 +1464,10 @@ ${BOLD}Do you want to continue?${RESET}" 20 80 || return
 
     # install bootloader.
     set_bootloader
+
+    # menu for enabling services
+    menu_services
+
     sync && sync && sync
 
     # unmount all filesystems.