manager: Show working mode

manager/app/src/main/cpp/jni.cc

@@ -46,6 +46,12 @@ Java_me_weishu_kernelsu_Natives_isSafeMode(JNIEnv *env, jclass clazz) {
     return is_safe_mode();
 }
 
+extern "C"
+JNIEXPORT jboolean JNICALL
+Java_me_weishu_kernelsu_Natives_isLkmMode(JNIEnv *env, jclass clazz) {
+    return is_lkm_mode();
+}
+
 static void fillIntArray(JNIEnv *env, jobject list, int *data, int count) {
     auto cls = env->GetObjectClass(list);
     auto add = env->GetMethodID(cls, "add", "(Ljava/lang/Object;)Z");

manager/app/src/main/cpp/ksu.cc

@@ -47,10 +47,14 @@ bool become_manager(const char* pkg) {
     return ksuctl(CMD_BECOME_MANAGER, param, nullptr);
 }
 
+// cache the result to avoid unnecessary syscall
+static bool is_lkm;
 int get_version() {
     int32_t version = -1;
-    if (ksuctl(CMD_GET_VERSION, &version, nullptr)) {
-        return version;
+    int32_t lkm = 0;
+    ksuctl(CMD_GET_VERSION, &version, &lkm);
+    if (!is_lkm && lkm != 0) {
+        is_lkm = true;
     }
     return version;
 }
@@ -63,6 +67,11 @@ bool is_safe_mode() {
     return ksuctl(CMD_CHECK_SAFEMODE, nullptr, nullptr);
 }
 
+bool is_lkm_mode() {
+    // you should call get_version first!
+    return is_lkm;
+}
+
 bool uid_should_umount(int uid) {
     bool should;
     return ksuctl(CMD_IS_UID_SHOULD_UMOUNT, reinterpret_cast<void*>(uid), &should) && should;

manager/app/src/main/cpp/ksu.h

@@ -17,6 +17,8 @@ bool uid_should_umount(int uid);
 
 bool is_safe_mode();
 
+bool is_lkm_mode();
+
 #define KSU_APP_PROFILE_VER 2
 #define KSU_MAX_PACKAGE_NAME 256
 // NGROUPS_MAX for Linux is 65535 generally, but we only supports 32 groups.