ksud: fix broken /system/vendor when it is a symlink

userspace/ksud/src/event.rs

@@ -13,6 +13,11 @@ fn mount_partition(partition: &str, lowerdir: &mut Vec<String>) {
         return;
     }
 
+    // if /partition is a symlink and linked to /system/partition, then we don't need to overlay it separately
+    if Path::new(&format!("/{}", partition)).read_link().is_ok() {
+        println!("partition: {} is a symlink", partition);
+        return;
+    }
     // add /partition as the lowerest dir
     let lowest_dir = format!("/{}", partition);
     lowerdir.push(lowest_dir.clone());
@@ -67,7 +72,9 @@ pub fn do_systemless_mount(module_dir: &str) -> Result<()> {
         system_lowerdir.push(format!("{}", module_system.display()));
 
         for part in &partition {
-            let part_path = Path::new(&module_system).join(part);
+            // if /partition is a mountpoint, we would move it to $MODPATH/$partition when install
+            // otherwise it must be a symlink and we don't need to overlay!
+            let part_path = Path::new(&module).join(part);
             if !part_path.exists() {
                 continue;
             }

userspace/ksud/src/installer.sh

@@ -281,6 +281,22 @@ is_legacy_script() {
   return $?
 }
 
+handle_partition() {
+    # if /system/vendor is a symlink, we need to move it out of $MODPATH/system, otherwise it will be overlayed
+    # if /system/vendor is a normal directory, it is ok to overlay it and we don't need to overlay it separately.
+    if [ ! -e $MODPATH/system/$1 ]; then
+        # no partition found
+        return;
+    fi
+
+    if [ -L "/system/$1" ] && [ "$(readlink -f /system/$1)" = "/$1" ]; then
+        ui_print "- Handle partition /$1"
+        # we create a symlink if module want to access $MODPATH/system/$1
+        # but it doesn't always work(ie. write it in post-fs-data.sh would fail because it is readonly)
+        mv -f $MODPATH/system/$1 $MODPATH/$1 && ln -sf /$1 $MODPATH/system/$1
+    fi
+}
+
 # Require OUTFD, ZIPFILE to be set
 install_module() {
   rm -rf $TMPDIR
@@ -355,6 +371,10 @@ install_module() {
     [ -f $MODPATH/customize.sh ] && . $MODPATH/customize.sh
   fi
 
+  handle_partition vendor
+  handle_partition system_ext
+  handle_partition product
+
   # Handle replace folders
   for TARGET in $REPLACE; do
     ui_print "- Replace target: $TARGET"