Create convert_fbe breadcrumb file to support conversion to FBE

Change-Id: I38b29e1e34ea793e4b87cd27a1d39fa905fddf7a

recovery.cpp

@@ -76,7 +76,10 @@ static const char *INTENT_FILE = "/cache/recovery/intent";
 static const char *LOG_FILE = "/cache/recovery/log";
 static const char *LAST_INSTALL_FILE = "/cache/recovery/last_install";
 static const char *LOCALE_FILE = "/cache/recovery/last_locale";
+static const char *CONVERT_FBE_DIR = "/cache/recovery/convert_fbe";
+static const char *CONVERT_FBE_FILE = "/cache/recovery/convert_fbe/convert_fbe";
 static const char *CACHE_ROOT = "/cache";
+static const char *DATA_ROOT = "/data";
 static const char *SDCARD_ROOT = "/sdcard";
 static const char *TEMPORARY_LOG_FILE = "/tmp/recovery.log";
 static const char *TEMPORARY_INSTALL_FILE = "/tmp/last_install";
@@ -503,6 +506,7 @@ typedef struct _saved_log_file {
 
 static bool erase_volume(const char* volume) {
     bool is_cache = (strcmp(volume, CACHE_ROOT) == 0);
+    bool is_data = (strcmp(volume, DATA_ROOT) == 0);
 
     ui->SetBackground(RecoveryUI::ERASING);
     ui->SetProgressType(RecoveryUI::INDETERMINATE);
@@ -557,7 +561,25 @@ static bool erase_volume(const char* volume) {
     ui->Print("Formatting %s...\n", volume);
 
     ensure_path_unmounted(volume);
-    int result = format_volume(volume);
+
+    int result;
+
+    if (is_data && reason && strcmp(reason, "convert_fbe") == 0) {
+        // Create convert_fbe breadcrumb file to signal to init
+        // to convert to file based encryption, not full disk encryption
+        mkdir(CONVERT_FBE_DIR, 0700);
+        FILE* f = fopen(CONVERT_FBE_FILE, "wb");
+        if (!f) {
+            ui->Print("Failed to convert to file encryption\n");
+            return true;
+        }
+        fclose(f);
+        result = format_volume(volume, CONVERT_FBE_DIR);
+        remove(CONVERT_FBE_FILE);
+        rmdir(CONVERT_FBE_DIR);
+    } else {
+        result = format_volume(volume);
+    }
 
     if (is_cache) {
         while (head) {

roots.cpp

@@ -175,7 +175,7 @@ static int exec_cmd(const char* path, char* const argv[]) {
     return WEXITSTATUS(status);
 }
 
-int format_volume(const char* volume) {
+int format_volume(const char* volume, const char* directory) {
     Volume* v = volume_for_path(volume);
     if (v == NULL) {
         LOGE("unknown volume \"%s\"\n", volume);
@@ -241,7 +241,7 @@ int format_volume(const char* volume) {
         }
         int result;
         if (strcmp(v->fs_type, "ext4") == 0) {
-            result = make_ext4fs(v->blk_device, length, volume, sehandle);
+            result = make_ext4fs_directory(v->blk_device, length, volume, sehandle, directory);
         } else {   /* Has to be f2fs because we checked earlier. */
             if (v->key_loc != NULL && strcmp(v->key_loc, "footer") == 0 && length < 0) {
                 LOGE("format_volume: crypt footer + negative length (%zd) not supported on %s\n", length, v->fs_type);
@@ -273,6 +273,10 @@ int format_volume(const char* volume) {
     return -1;
 }
 
+int format_volume(const char* volume) {
+    return format_volume(volume, NULL);
+}
+
 int setup_install_mounts() {
     if (fstab == NULL) {
         LOGE("can't set up install mounts: no fstab loaded\n");

roots.h

@@ -41,6 +41,12 @@ int ensure_path_unmounted(const char* path);
 // it is mounted.
 int format_volume(const char* volume);
 
+// Reformat the given volume (must be the mount point only, eg
+// "/cache"), no paths permitted.  Attempts to unmount the volume if
+// it is mounted.
+// Copies 'directory' to root of the newly formatted volume
+int format_volume(const char* volume, const char* directory);
+
 // Ensure that all and only the volumes that packages expect to find
 // mounted (/tmp and /cache) are mounted.  Returns 0 on success.
 int setup_install_mounts();