Fix meizu compatibility

native/jni/init/init.hpp

@@ -42,8 +42,8 @@ void setup_klog();
 
 class BaseInit {
 protected:
-    cmdline *cmd;
-    char **argv;
+    cmdline *cmd = nullptr;
+    char **argv = nullptr;
 
     [[noreturn]] void exec_init();
     void read_dt_fstab(std::vector<fstab_entry> &fstab);
@@ -67,7 +67,7 @@ public:
     MagiskInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {}
 };
 
-class SARBase : public MagiskInit {
+class SARBase : virtual public MagiskInit {
 protected:
     std::vector<raw_file> overlays;
 
@@ -75,7 +75,7 @@ protected:
     void patch_rootdir();
     void mount_system_root();
 public:
-    SARBase(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd) {}
+    SARBase() = default;
 };
 
 /***************
@@ -95,20 +95,6 @@ public:
     }
 };
 
-class SecondStageInit : public SARBase {
-private:
-    void prepare();
-public:
-    SecondStageInit(char *argv[]) : SARBase(argv, nullptr) {
-        LOGD("%s\n", __FUNCTION__);
-    };
-    void start() override {
-        prepare();
-        patch_rootdir();
-        exec_init();
-    }
-};
-
 /*************
  * Legacy SAR
  *************/
@@ -120,7 +106,7 @@ private:
     void early_mount();
     void first_stage_prep();
 public:
-    SARInit(char *argv[], cmdline *cmd) : SARBase(argv, cmd), is_two_stage(false) {
+    SARInit(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd), is_two_stage(false) {
         LOGD("%s\n", __FUNCTION__);
     };
     void start() override {
@@ -137,10 +123,18 @@ public:
  * Initramfs
  ************/
 
-class RootFSInit : public MagiskInit {
+class RootFSBase : virtual public MagiskInit {
+protected:
+    void patch_rootfs();
+public:
+    RootFSBase() = default;
+    void start() = 0;
+};
+
+class RootFSInit : public RootFSBase {
 private:
     void early_mount();
-    void patch_rootfs();
+
 public:
     RootFSInit(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd) {
         LOGD("%s\n", __FUNCTION__);
@@ -152,6 +146,22 @@ public:
     }
 };
 
+class SecondStageInit : public RootFSBase, public SARBase {
+private:
+    bool prepare();
+public:
+    SecondStageInit(char *argv[]) : MagiskInit(argv, nullptr) {
+        LOGD("%s\n", __FUNCTION__);
+    };
+
+    void start() override {
+        if (prepare()) patch_rootfs();
+        else patch_rootdir();
+        exec_init();
+    }
+};
+
+
 class MagiskProxy : public MagiskInit {
 public:
     explicit MagiskProxy(char *argv[]) : MagiskInit(argv, nullptr) {

native/jni/init/mount.cpp

@@ -185,7 +185,7 @@ static void switch_root(const string &path) {
     });
     for (auto &dir : mounts) {
         auto new_path = path + dir;
-        mkdir(new_path.data(), 0755);
+        xmkdir(new_path.data(), 0755);
         xmount(dir.data(), new_path.data(), nullptr, MS_MOVE, nullptr);
     }
     chdir(path.data());
@@ -355,14 +355,24 @@ void SARInit::early_mount() {
     }
 }
 
-void SecondStageInit::prepare() {
+bool SecondStageInit::prepare() {
     backup_files();
 
     umount2("/init", MNT_DETACH);
     umount2("/proc/self/exe", MNT_DETACH);
 
-    if (access("/system_root", F_OK) == 0)
+    // some weird devices, like meizu, embrace two stage init but still have legacy rootfs behaviour
+    bool legacy = false;
+    if (access("/system_root", F_OK) == 0) {
+        if (access("/system_root/proc", F_OK) == 0) {
             switch_root("/system_root");
+        } else {
+            xmount("/system_root", "/system", nullptr, MS_MOVE, nullptr);
+            rmdir("/system_root");
+            legacy = true;
+        }
+    }
+    return legacy;
 }
 
 void BaseInit::exec_init() {

native/jni/init/rootdir.cpp

@@ -15,6 +15,10 @@ static vector<string> rc_list;
 
 static void patch_init_rc(const char *src, const char *dest, const char *tmp_dir) {
     FILE *rc = xfopen(dest, "we");
+    if (!rc) {
+        PLOGE("%s: open %s failed", __PRETTY_FUNCTION__, src);
+        return;
+    }
     file_readline(src, [=](string_view line) -> bool {
         // Do not start vaultkeeper
         if (str_contains(line, "start vaultkeeper")) {
@@ -157,6 +161,7 @@ static string magic_mount_list;
 
 static void magic_mount(const string &sdir, const string &ddir = "") {
     auto dir = xopen_dir(sdir.data());
+    if (!dir) return;
     for (dirent *entry; (entry = xreaddir(dir.get()));) {
         string src = sdir + "/" + entry->d_name;
         string dest = ddir + "/" + entry->d_name;
@@ -321,7 +326,7 @@ void SARBase::patch_rootdir() {
 #define TMP_MNTDIR "/dev/mnt"
 #define TMP_RULESDIR "/.backup/.sepolicy.rules"
 
-void RootFSInit::patch_rootfs() {
+void RootFSBase::patch_rootfs() {
     // Create hardlink mirror of /sbin to /root
     mkdir("/root", 0777);
     clone_attr("/sbin", "/root");
@@ -338,8 +343,11 @@ void RootFSInit::patch_rootfs() {
     }
 
     if (patch_sepolicy("/sepolicy")) {
-        auto init = mmap_data::rw("/init");
+        auto init = mmap_data::ro(access("/system/bin/init",F_OK) == 0 ? "/system/bin/init" : "/init");
         init.patch({ make_pair(SPLIT_PLAT_CIL, "xxx") });
+        int dest = xopen("/init", O_TRUNC | O_WRONLY | O_CLOEXEC, 0);
+        xwrite(dest, init.buf, init.sz);
+        close(dest);
     }
 
     // Handle overlays

native/jni/utils/files.cpp

@@ -423,7 +423,7 @@ void restore_folder(const char *dir, vector<raw_file> &files) {
             mkdirs(path.data(), 0);
         } else if (S_ISREG(file.attr.st.st_mode)) {
             auto fp = xopen_file(path.data(), "we");
-            fwrite(file.buf, 1, file.sz, fp.get());
+            if (fp) fwrite(file.buf, 1, file.sz, fp.get());
         } else if (S_ISLNK(file.attr.st.st_mode)) {
             symlink((char *)file.buf, path.data());
         }