kernel: Add the real UID by parsing the UID from the /data/user_de/0/[app] directory

Prioritize retrieving the application UID from /data/user_de. If this fails, fall back to retrieving it from packages.list.

Fix unstable application UID acquisition

Signed-off-by: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>

kernel/kernel_compat.h

@@ -4,9 +4,39 @@
 #include <linux/fs.h>
 #include <linux/version.h>
 #include <linux/cred.h>
+#include <linux/list.h>
 #include "ss/policydb.h"
 #include "linux/key.h"
 
+/**
+ * list_count_nodes - count the number of nodes in a list
+ * @head: the head of the list
+ *
+ * This function iterates over the list starting from @head and counts
+ * the number of nodes in the list. It does not modify the list.
+ *
+ * Context: Any context. The function is safe to call in any context,
+ *          including interrupt context, as it does not sleep or allocate
+ *          memory.
+ *
+ * Return: the number of nodes in the list (excluding the head)
+ */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(6, 6, 0)
+static inline __maybe_unused size_t list_count_nodes(const struct list_head *head)
+{
+    const struct list_head *pos;
+    size_t count = 0;
+
+    if (!head)
+        return 0;
+
+    list_for_each(pos, head)
+        count++;
+
+	return count;
+}
+#endif
+
 /*
  * Adapt to Huawei HISI kernel without affecting other kernels ,
  * Huawei Hisi Kernel EBITMAP Enable or Disable Flag ,