Fix /data/adb/magisk permissions so Zygisk can initialise

General.install() runs copy() -> extra1() -> set_perm(). set_perm() only walks
self.files, which are paths under copy_dir (the overlay), so the copy that
Magisk.setup() makes into <data_dir>/adb/magisk keeps the 0644 the binaries
inherit from the apk extraction.

A non-executable /data/adb/magisk/magisk64 makes magisk_env() abort at
post-fs-data. Root still works, because that runs from the overlay copy, but
Zygisk never initialises: the Magisk app reports "Zygisk: No" no matter what the
zygisk setting says, and no error is surfaced to explain why. This breaks every
Zygisk module (LSPosed, Shamiko, PlayIntegrityFix, ...).

Fix setup() to apply the same 0755 to its own destination that
Magisk.set_path_perm() already applies to magisk paths.

Adds a regression test that passes with the fix and fails without it. It needs no
Waydroid install, no root and no extra dependencies:

    python3 tests/test_magisk_setup_perms.py

Fixes #283

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

stuff/magisk.py

@@ -64,7 +64,28 @@ on property:init.svc.zygote=stopped
         Logger.info("Additional setup")
         magisk_absolute_dir = os.path.join(self.copy_dir, self.magisk_dir)
         data_dir = get_data_dir()
-        shutil.copytree(magisk_absolute_dir, os.path.join(data_dir, "adb", "magisk"), dirs_exist_ok=True)
+        data_magisk_dir = os.path.join(data_dir, "adb", "magisk")
+        shutil.copytree(magisk_absolute_dir, data_magisk_dir, dirs_exist_ok=True)
+
+        # General.install() calls set_perm() only over self.files, which are paths
+        # under copy_dir (the overlay). This /data/adb copy is made here, before
+        # that runs, so it keeps the 0644 the binaries inherited from the apk
+        # extraction. A non-executable /data/adb/magisk/magisk64 makes magisk_env()
+        # abort at post-fs-data: root still works from the overlay copy, but Zygisk
+        # silently never initialises (Magisk reports "Zygisk: No" no matter what
+        # the zygisk setting says). Apply the same perms set_path_perm() gives
+        # magisk paths, to this copy too.
+        self.set_data_magisk_perm(data_magisk_dir)
+
+    def set_data_magisk_perm(self, data_magisk_dir):
+        if not os.path.isdir(data_magisk_dir):
+            return
+        os.chmod(data_magisk_dir, 0o755)
+        for root, dirnames, filenames in os.walk(data_magisk_dir):
+            for dirname in dirnames:
+                os.chmod(os.path.join(root, dirname), 0o755)
+            for filename in filenames:
+                os.chmod(os.path.join(root, filename), 0o755)
 
     def copy(self):
         magisk_absolute_dir = os.path.join(self.copy_dir, self.magisk_dir)