Progress towards dynamic storage support.
Storage devices are no longer hard-coded, and instead bubble up from
whatever Disk and VolumeBase that vold uncovered, turning into
sibling Java objects in MountService. We now treat vold events as
the source-of-truth for state, and synchronize our state by asking
vold to "reset" whenever we reconnect.
We've now moved to a model where all storage devices are mounted in
the root mount namespace (user boundaries protected with GIDs), so
we no longer need app-to-vold path translation. This also means that
zygote only needs to bind mount the user-specific /mnt/user/n/ path
onto /storage/self/ to make legacy paths like /sdcard work. This
grealy simplifies a lot of system code.
Many parts of the platform depend on a primary storage device always
being present, so we hack together a stub StorageVolume when vold
doesn't have a volume ready yet.
StorageVolume isn't really a volume anymore; it's the user-specific
view onto a volume, so MountService now filters and builds them
based on the calling user. StorageVolume is now immutable, making
it easier to reason about.
Environment now builds all of its paths dynamically based on active
volumes. Adds utility methods to turn int types and flags into
user-readable strings for debugging purposes.
Remove UMS sharing support for now, since no current devices support
it; MTP is the recommended solution going forward because it offers
better multi-user support.
Simplify unmount logic, since vold will now gladly trigger EJECTING
broadcast and kill stubborn processes.
Bug: 19993667
Change-Id: I9842280e61974c91bae15d764e386969aedcd338
diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp
index 2bfeadb..76db5d3 100644
--- a/core/jni/com_android_internal_os_Zygote.cpp
+++ b/core/jni/com_android_internal_os_Zygote.cpp
@@ -65,9 +65,7 @@
// Must match values in com.android.internal.os.Zygote.
enum MountExternalKind {
MOUNT_EXTERNAL_NONE = 0,
- MOUNT_EXTERNAL_SINGLEUSER = 1,
- MOUNT_EXTERNAL_MULTIUSER = 2,
- MOUNT_EXTERNAL_MULTIUSER_ALL = 3,
+ MOUNT_EXTERNAL_DEFAULT = 1,
};
static void RuntimeAbort(JNIEnv* env) {
@@ -269,57 +267,16 @@
// See storage config details at http://source.android.com/tech/storage/
userid_t user_id = multiuser_get_user_id(uid);
- // Create bind mounts to expose external storage
- if (mount_mode == MOUNT_EXTERNAL_MULTIUSER || mount_mode == MOUNT_EXTERNAL_MULTIUSER_ALL) {
- // These paths must already be created by init.rc
- const char* source = getenv("EMULATED_STORAGE_SOURCE");
- const char* target = getenv("EMULATED_STORAGE_TARGET");
- const char* legacy = getenv("EXTERNAL_STORAGE");
- if (source == NULL || target == NULL || legacy == NULL) {
- ALOGW("Storage environment undefined; unable to provide external storage");
- return false;
- }
+ // Bind mount user-specific storage into place
+ const String8 source(String8::format("/mnt/user/%d", user_id));
+ const String8 target(String8::format("/storage/self"));
- // Prepare source paths
+ if (fs_prepare_dir(source.string(), 0755, 0, 0) == -1) {
+ return false;
+ }
- // /mnt/shell/emulated/0
- const String8 source_user(String8::format("%s/%d", source, user_id));
- // /storage/emulated/0
- const String8 target_user(String8::format("%s/%d", target, user_id));
-
- if (fs_prepare_dir(source_user.string(), 0000, 0, 0) == -1
- || fs_prepare_dir(target_user.string(), 0000, 0, 0) == -1) {
- return false;
- }
-
- if (mount_mode == MOUNT_EXTERNAL_MULTIUSER_ALL) {
- // Mount entire external storage tree for all users
- if (TEMP_FAILURE_RETRY(mount(source, target, NULL, MS_BIND, NULL)) == -1) {
- ALOGW("Failed to mount %s to %s: %s", source, target, strerror(errno));
- return false;
- }
- } else {
- // Only mount user-specific external storage
- if (TEMP_FAILURE_RETRY(mount(source_user.string(), target_user.string(), NULL,
- MS_BIND, NULL)) == -1) {
- ALOGW("Failed to mount %s to %s: %s", source_user.string(), target_user.string(),
- strerror(errno));
- return false;
- }
- }
-
- if (fs_prepare_dir(legacy, 0000, 0, 0) == -1) {
- return false;
- }
-
- // Finally, mount user-specific path into place for legacy users
- if (TEMP_FAILURE_RETRY(
- mount(target_user.string(), legacy, NULL, MS_BIND | MS_REC, NULL)) == -1) {
- ALOGW("Failed to mount %s to %s: %s", target_user.string(), legacy, strerror(errno));
- return false;
- }
- } else {
- ALOGW("Mount mode %d unsupported", mount_mode);
+ if (TEMP_FAILURE_RETRY(mount(source.string(), target.string(), NULL, MS_BIND, NULL)) == -1) {
+ ALOGW("Failed to mount %s to %s: %s", source.string(), target.string(), strerror(errno));
return false;
}