This is the basic infrastructure for pulling a full(*) backup of the
device's data over an adb(**) connection to the local device. The
basic process consists of these interacting pieces:
1. The framework's BackupManagerService, which coordinates the
collection of app data and routing to the destination.
2. A new framework-provided BackupAgent implementation called
FullBackupAgent, which is instantiated in the target applications'
processes in turn, and knows how to emit a datastream that contains
all of the app's saved data files.
3. A new shell-level program called "bu" that is used to bridge from
adb to the framework's Backup Manager.
4. adb itself, which now knows how to use 'bu' to kick off a backup
operation and pull the resulting data stream to the desktop host.
5. A system-provided application that verifies with the user that
an attempted backup/restore operation is in fact expected and to
be allowed.
The full agent implementation is not used during normal operation of
the delta-based app-customized remote backup process. Instead it's
used during user-confirmed *full* backup of applications and all their
data to a local destination, e.g. via the adb connection.
The output format is 'tar'. This makes it very easy for the end
user to examine the resulting dataset, e.g. for purpose of extracting
files for debug purposes; as well as making it easy to contemplate
adding things like a direct gzip stage to the data pipeline during
backup/restore. It also makes it convenient to construct and maintain
synthetic backup datasets for testing purposes.
Within the tar format, certain artificial conventions are used.
All files are stored within top-level directories according to
their semantic origin:
apps/pkgname/a/ : Application .apk file itself
apps/pkgname/obb/: The application's associated .obb containers
apps/pkgname/f/ : The subtree rooted at the getFilesDir() location
apps/pkgname/db/ : The subtree rooted at the getDatabasePath() parent
apps/pkgname/sp/ : The subtree rooted at the getSharedPrefsFile() parent
apps/pkgname/r/ : Files stored relative to the root of the app's file tree
apps/pkgname/c/ : Reserved for the app's getCacheDir() tree; not stored.
For each package, the first entry in the tar stream is a file called
"_manifest", nominally rooted at apps/pkgname. This file contains some
metadata about the package whose data is stored in the archive.
The contents of shared storage can optionally be included in the tar
stream. It is placed in the synthetic location:
shared/...
uid/gid are ignored; app uids are assigned at install time, and the
app's data is handled from within its own execution environment, so
will automatically have the app's correct uid.
Forward-locked .apk files are never backed up. System-partition
.apk files are not backed up unless they have been overridden by a
post-factory upgrade, in which case the current .apk *is* backed up --
i.e. the .apk that matches the on-disk data. The manifest preceding
each application's portion of the tar stream provides version numbers
and signature blocks for version checking, as well as an indication
of whether the restore logic should expect to install the .apk before
extracting the data.
System packages can designate their own full backup agents. This is
to manage things like the settings provider which (a) cannot be shut
down on the fly in order to do a clean snapshot of their file trees,
and (b) manage data that is not only irrelevant but actively hostile
to non-identical devices -- CDMA telephony settings would seriously
mess up a GSM device if emplaced there blind, for example.
When a full backup or restore is initiated from adb, the system will
present a confirmation UI that the user must explicitly respond to
within a short [~ 30 seconds] timeout. This is to avoid the
possibility of malicious desktop-side software secretly grabbing a copy
of all the user's data for nefarious purposes.
(*) The backup is not strictly a full mirror. In particular, the
settings database is not cloned; it is handled the same way that
it is in cloud backup/restore. This is because some settings
are actively destructive if cloned onto a different (or
especially a different-model) device: telephony settings and
AndroidID are good examples of this.
(**) On the framework side it doesn't care that it's adb; it just
sends the tar stream to a file descriptor. This can easily be
retargeted around whatever transport we might decide to use
in the future.
KNOWN ISSUES:
* the security UI is desperately ugly; no proper designs have yet
been done for it
* restore is not yet implemented
* shared storage backup is not yet implemented
* symlinks aren't yet handled, though some infrastructure for
dealing with them has been put in place.
Change-Id: Ia8347611e23b398af36ea22c36dff0a276b1ce91
* commit '315595d10dfd4b8fe32cfe45a53f9e342bf0a699':
docs: update screen support doc to de-emphasize support for 1.5 this includes a variety of other revisions to reorganize some of the content in the main document and also add separate documents for how to enable screen filtering and add screen support on 1.5
* commit '6b2c8f00c95d05a8ca410ff74451fd0701f36119':
docs: update screen support doc to de-emphasize support for 1.5 this includes a variety of other revisions to reorganize some of the content in the main document and also add separate documents for how to enable screen filtering and add screen support on 1.5
* commit 'fef7b62506a74d0133b60fd1d6ae9bf54bf599c9':
docs: update screen support doc to de-emphasize support for 1.5 this includes a variety of other revisions to reorganize some of the content in the main document and also add separate documents for how to enable screen filtering and add screen support on 1.5
* commit '7f3cf449fe1b90b902a37ddc3c05ec7aa236e584':
docs: update screen support doc to de-emphasize support for 1.5 this includes a variety of other revisions to reorganize some of the content in the main document and also add separate documents for how to enable screen filtering and add screen support on 1.5
First step of improving app screen size compatibility mode. When
running in compat mode, an application's windows are scaled up on
the screen rather than being small with 1:1 pixels.
Currently we scale the application to fill the entire screen, so
don't use an even pixel scaling. Though this may have some
negative impact on the appearance (it looks okay to me), it has a
big benefit of allowing us to now treat these apps as normal
full-screens apps and do the normal transition animations as you
move in and out and around in them.
This introduces fun stuff in the input system to take care of
modifying pointer coordinates to account for the app window
surface scaling. The input dispatcher is told about the scale
that is being applied to each window and, when there is one,
adjusts pointer events appropriately as they are being sent
to the transport.
Also modified is CompatibilityInfo, which has been greatly
simplified to not be so insane and incomprehendible. It is
now simple -- when constructed it determines if the given app
is compatible with the current screen size and density, and
that is that.
There are new APIs on ActivityManagerService to put applications
that we would traditionally consider compatible with larger screens
in compatibility mode. This is the start of a facility to have
a UI affordance for a user to switch apps in and out of
compatibility.
To test switching of modes, there is a new variation of the "am"
command to do this: am screen-compat [on|off] [package]
This mode switching has the fundamentals of restarting activities
when it is changed, though the state still needs to be persisted
and the overall mode switch cleaned up.
For the few small apps I have tested, things mostly seem to be
working well. I know of one problem with the text selection
handles being drawn at the wrong position because at some point
the window offset is being scaled incorrectly. There are
probably other similar issues around the interaction between
two windows because the different window coordinate spaces are
done in a hacky way instead of being formally integrated into
the window manager layout process.
Change-Id: Ie038e3746b448135117bd860859d74e360938557
