`adb pull` from app data directory without root access

readme.md

TL;DR;

com.package.name is your app identifier, and the file path is relative to the app user's home directory, e.g. '/data/user/0/com.package.name.

adb shell run-as com.package.name cp relative/path/file.ext /sdcard
adb pull /sdcard/file.ext

See long explanation below.

Problem

Trying to adb pull files from our app's directory fails with Permission denied, because the adb user doesn't have access to the home directory.

adb pull /data/user/0/com.package.name/file.ext

Error:

adb: error: failed to stat remote object '/data/user/0/com.package.name/file.ext': Permission denied

You can try to run adb as root first:

adb root

But on a non-rooted device, this fails with:

adbd cannot run as root in production builds`

Here's a workaround on how to download a file from the app data directory using run-as.

Long version

This explains the solution step by step.

Start a shell session on the device. All following commands will be executed in the shell session on your device.

adb shell

Assuming our app identifier is com.package.name, the app data directory is at /data/user/0/com.package.name.

You can try to list files in that directory:

ls /data/user/0/com.package.name

This should result in error:

ls: /data/user/0/com.package.name/: Permission denied

However, you can run a command using the com.package.name application identity with the run-as command

run-as com.package.name ls /data/user/0/com.package.name/

You should now see a directory listing, and you can find the file you want, and copy it to a directory on your device that doesn't require root access, e.g. /sdcard:

run-as com.package.name cp /data/user/0/com.package.name/file.ext /sdcard

We can then exit the adb shell:

exit

Back at our own computer, we can adb pull the file:

adb pull /sdcard/file.ext

this will remove the file data before backed up