Revert DTB fstab changes

gradle.properties

@@ -27,6 +27,6 @@ android.injected.testOnly=false
 kapt.incremental.apt=true
 
 # Magisk
-magisk.versionCode=21201
+magisk.versionCode=21202
 magisk.ndkVersion=21d
 magisk.fullNdkVersion=21.3.6528147

native/jni/init/twostage.cpp

@@ -57,13 +57,39 @@ void FirstStageInit::prepare() {
     }
 exit_loop:
 
-    if (fstab_file[0] == '\0') {
-        LOGI("Cannot find fstab file in ramdisk!\n");
-        return;
+    // Try to load dt fstab
+    vector<fstab_entry> fstab;
+    read_dt_fstab(fstab);
+
+    if (!fstab.empty()) {
+        // Dump dt fstab to fstab file in rootfs and force init to use it instead
+
+        // All dt fstab entries should be first_stage_mount
+        for (auto &entry : fstab) {
+            if (!str_contains(entry.fsmgr_flags, "first_stage_mount")) {
+                if (!entry.fsmgr_flags.empty())
+                    entry.fsmgr_flags += ',';
+                entry.fsmgr_flags += "first_stage_mount";
+            }
         }
 
-    // Parse and load fstab file
-    vector<fstab_entry> fstab;
+        if (fstab_file[0] == '\0') {
+            const char *suffix =
+                    cmd->fstab_suffix[0] ? cmd->fstab_suffix :
+                    (cmd->hardware[0] ? cmd->hardware :
+                    (cmd->hardware_plat[0] ? cmd->hardware_plat : nullptr));
+            if (suffix == nullptr) {
+                LOGE("Cannot determine fstab suffix!\n");
+                return;
+            }
+            sprintf(fstab_file, "fstab.%s", suffix);
+        }
+
+        // Patch init to force IsDtFstabCompatible() return false
+        auto init = mmap_data::rw("/init");
+        init.patch({ make_pair("android,fstab", "xxx") });
+    } else {
+        // Parse and load the fstab file
         file_readline(fstab_file, [&](string_view l) -> bool {
             if (l[0] == '#' || l.length() == 1)
                 return true;
@@ -87,6 +113,7 @@ exit_loop:
             fstab.emplace_back(std::move(entry));
             return true;
         });
+    }
 
     {
         LOGD("Write fstab file: %s\n", fstab_file);

native/jni/magiskboot/dtb.cpp

@@ -124,52 +124,37 @@ static void dtb_print(const char *file, bool fstab) {
     munmap(dtb, size);
 }
 
+[[maybe_unused]]
 static bool dtb_patch_rebuild(uint8_t *dtb, size_t dtb_sz, const char *file);
 
 static bool dtb_patch(const char *file) {
     bool keep_verity = check_env("KEEPVERITY");
-    bool have_system = false;
-    vector<pair<char *, int>> flags_list;
 
     size_t size;
     uint8_t *dtb;
     fprintf(stderr, "Loading dtbs from [%s]\n", file);
     mmap_rw(file, dtb, size);
-    run_finally f([=]{ munmap(dtb, size); });
 
-    // First traverse through DTB to determine whether we need a rebuild
-    int dtb_num = 0;
+    bool patched = false;
     for (int i = 0; i < size; ++i) {
         if (memcmp(dtb + i, FDT_MAGIC_STR, 4) == 0) {
             auto fdt = dtb + i;
             if (int fstab = find_fstab(fdt); fstab >= 0) {
                 int node;
                 fdt_for_each_subnode(node, fdt, fstab) {
-                    const char *name = fdt_get_name(fdt, node, nullptr);
                     if (!keep_verity) {
                         int len;
                         char *value = (char *) fdt_getprop(fdt, node, "fsmgr_flags", &len);
-                        flags_list.emplace_back(value, len);
+                        patched |= patch_verity(value, len) != len;
                     }
-                    if (name == "system"sv)
-                        have_system = true;
                 }
             }
             i += fdt_totalsize(fdt) - 1;
-            ++dtb_num;
         }
     }
 
-    if (!have_system) {
-        // Patch in place with rw mmap
-        bool patched = false;
-        for (auto &[value, len] : flags_list)
-            patched |= patch_verity(value, len) != len;
+    munmap(dtb, size);
     return patched;
-    } else {
-        // Need to rebuild dtb due to additional props
-        return dtb_patch_rebuild(dtb, size, file);
-    }
 }
 
 int dtb_commands(int argc, char *argv[]) {