Move find_apk_path to Rust

native/src/core/daemon.rs

@@ -1,8 +1,12 @@
-use crate::logging::{magisk_logging, zygisk_logging};
 use std::cell::RefCell;
 use std::fs::File;
+use std::io;
 use std::sync::{Mutex, OnceLock};
 
+use base::{copy_str, cstr, Directory, ResultExt, WalkResult};
+
+use crate::logging::{magisk_logging, zygisk_logging};
+
 // Global magiskd singleton
 pub static MAGISKD: OnceLock<MagiskD> = OnceLock::new();
 
@@ -29,3 +33,30 @@ pub fn get_magiskd() -> &'static MagiskD {
 }
 
 impl MagiskD {}
+
+pub fn find_apk_path(pkg: &[u8], data: &mut [u8]) -> usize {
+    use WalkResult::*;
+    fn inner(pkg: &[u8], data: &mut [u8]) -> io::Result<usize> {
+        let mut len = 0_usize;
+        Directory::open(cstr!("/data/app"))?.pre_order_walk(|e| {
+            if !e.is_dir() {
+                return Ok(Skip);
+            }
+            let d_name = e.d_name().to_bytes();
+            if d_name.starts_with(pkg) && d_name[pkg.len()] == b'-' {
+                // Found the APK path, we can abort now
+                len = e.path(data)?;
+                return Ok(Abort);
+            }
+            if d_name.starts_with(b"~~") {
+                return Ok(Continue);
+            }
+            Ok(Skip)
+        })?;
+        if len > 0 {
+            len += copy_str(&mut data[len..], "/base.apk");
+        }
+        Ok(len)
+    }
+    inner(pkg, data).log().unwrap_or(0)
+}

native/src/core/lib.rs

@@ -21,6 +21,7 @@ pub mod ffi {
         fn android_logging();
         fn magisk_logging();
         fn zygisk_logging();
+        fn find_apk_path(pkg: &[u8], data: &mut [u8]) -> usize;
     }
 
     #[namespace = "rust"]

native/src/core/package.cpp

@@ -169,8 +169,9 @@ int get_manager(int user_id, string *pkg, bool install) {
                 if (stat(app_path, &st) == 0) {
                     int app_id = to_app_id(st.st_uid);
 
-                    string apk = find_apk_path(str[SU_MANAGER].data());
-                    int fd = xopen(apk.data(), O_RDONLY | O_CLOEXEC);
+                    byte_array<PATH_MAX> apk;
+                    find_apk_path(byte_view(str[SU_MANAGER]), apk);
+                    int fd = xopen((const char *) apk.buf(), O_RDONLY | O_CLOEXEC);
                     string cert = read_certificate(fd);
                     close(fd);
 
@@ -178,7 +179,7 @@ int get_manager(int user_id, string *pkg, bool install) {
                     if (str[SU_MANAGER] == *mgr_pkg) {
                         if (app_id != mgr_app_id || cert != *mgr_cert) {
                             // app ID or cert should never change
-                            LOGE("pkg: repackaged APK signature invalid: %s\n", apk.data());
+                            LOGE("pkg: repackaged APK signature invalid: %s\n", apk.buf());
                             uninstall_pkg(mgr_pkg->data());
                             invalid = true;
                             install = true;