manager: added mount system switchability

userspace: added ksud_overlayfs & ksud_magic

userspace/ksud_magic/src/debug.rs

@@ -0,0 +1,52 @@
+use anyhow::{ensure, Context, Ok, Result};
+use std::{
+    path::{Path, PathBuf},
+    process::Command,
+};
+
+const KERNEL_PARAM_PATH: &str = "/sys/module/kernelsu";
+
+fn read_u32(path: &PathBuf) -> Result<u32> {
+    let content = std::fs::read_to_string(path)?;
+    let content = content.trim();
+    let content = content.parse::<u32>()?;
+    Ok(content)
+}
+
+fn set_kernel_param(uid: u32) -> Result<()> {
+    let kernel_param_path = Path::new(KERNEL_PARAM_PATH).join("parameters");
+
+    let ksu_debug_manager_uid = kernel_param_path.join("ksu_debug_manager_uid");
+    let before_uid = read_u32(&ksu_debug_manager_uid)?;
+    std::fs::write(&ksu_debug_manager_uid, uid.to_string())?;
+    let after_uid = read_u32(&ksu_debug_manager_uid)?;
+
+    println!("set manager uid: {before_uid} -> {after_uid}");
+
+    Ok(())
+}
+
+#[cfg(target_os = "android")]
+fn get_pkg_uid(pkg: &str) -> Result<u32> {
+    // stat /data/data/<pkg>
+    let uid = rustix::fs::stat(format!("/data/data/{pkg}"))
+        .with_context(|| format!("stat /data/data/{}", pkg))?
+        .st_uid;
+    Ok(uid)
+}
+
+pub fn set_manager(pkg: &str) -> Result<()> {
+    ensure!(
+        Path::new(KERNEL_PARAM_PATH).exists(),
+        "CONFIG_KSU_DEBUG is not enabled"
+    );
+
+    #[cfg(target_os = "android")]
+    let uid = get_pkg_uid(pkg)?;
+    #[cfg(not(target_os = "android"))]
+    let uid = 0;
+    set_kernel_param(uid)?;
+    // force-stop it
+    let _ = Command::new("am").args(["force-stop", pkg]).status();
+    Ok(())
+}