Add a broken symlink resolver to login (as well)

src/pkgs/files/login.nix

@@ -7,11 +7,73 @@ writeScriptBin "login" ''
   #!/system/bin/sh
   set -e
 
+  ORIGINAL_PATH="$PATH"
+  ANDROID_LIKELY_PATH="/sbin:/system/sbin:/system/bin:/system/xbin"
+  ANDROID_LIKELY_PATH="$ANDROID_LIKELY_PATH:/vendor/bin:/vendor/xbin"
+  PATH="$ANDROID_LIKELY_PATH:$OLD_PATH"
+
+  resolve_link() {
+    #echo "resolving $1" >&2
+    if [ -x "$1" ]; then
+      #echo "$1 exists, done" >&2
+      echo "$1"
+    elif [ -L "$1" ]; then
+      TGT=$(readlink "$1")
+      #echo "$1 is a link pointing to $TGT" >&2
+      case $TGT in
+        /data/data/com.termux.nix/files/*)  # some parent is a broken link
+          #echo "$TGT link looks fine, resolving further" >&2
+          resolve_link "$TGT"
+        ;;
+        /*)  # broken link, just add the prefix
+          #echo "$TGT makes sense only inside nix-on-droid, fixing it" >&2
+          resolve_link "/data/data/com.termux.nix/files/usr$TGT"
+        ;;
+        *)  # relative link, replace parent
+          TGT="$(dirname "$1")/$TGT"
+          #echo "This link is a relative link, resolve it as $TGT" >&2
+          resolve_link "$TGT"
+        ;;
+      esac
+    else  # OK, now some parent is a broken link =/
+      #echo "=/" >&2
+      P=$1
+      TAIL=""                          # /something/broken_symlink/smth/else
+      while [ ! -e "$P" ]; do          # /something/broken_symlink/smth (iter 2)
+        TAIL="$(basename "$P")/$TAIL"  # something/else/                (iter 2)
+        P=$(dirname "$P")              # /something/broken_symlink      (iter 2)
+        #echo "inspecting $P" >&2
+        if [ -L "$P" ] && [ ! -x "$P" ]; then
+          TAIL=''${TAIL%%/}  # strip slashes
+          #echo "$P is the broken symlink parent, fix that and add $TAIL" >&2
+          P="$(resolve_link "$P")"
+          #echo "resolved to $P, now adding $TAIL" >&2
+          resolve_link "$P/$TAIL"
+        break
+        #else
+          #echo "$P is not a symlink, we need to go deeper" >&2
+        fi
+      done
+    fi
+  }
+
+  instDir=/data/data/com.termux.nix/files/usr
+
   export USER=nix-on-droid
   export PROOT_TMP_DIR=${instDir}/tmp
   export PROOT_L2S_DIR=${instDir}/.l2s
 
-  exec ${instDir}/bin/proot \
+  PROOT=${instDir}/bin/proot-static
+  if [ ! -x "$PROOT" ]; then
+    PROOT=$(resolve_link "$PROOT")
+  fi
+  if [ ! -x "$PROOT" ]; then
+    echo "Could not find proot-static" >&2
+    exit 244
+  fi
+
+  PATH="$ORIGINAL_PATH"
+  exec "$PROOT" \
     -b ${instDir}/nix:/nix \
     -b ${instDir}/bin:/bin \
     -b ${instDir}/etc:/etc \