copy file to /data/local/tmp

Question

I want to copy some files from it's own data folder(e.g. "/data/data/com.example.copy/") to "/data/local/tmp/". I can't access /data/local/tmp/ in my app. Is it possible to do it? I don't have root access on my device.

Here's my code:

Process p=Runtime.getRuntime().exec("cat "+ this.getApplicationInfo().dataDir +"1.txt > /data/local/tmp/1.txt" );
p.waitFor();

Solution

No, you cannot do this from an application unless your device has something like a hacked su which lets you run a helper process as a more privileged user (ie, unless it is "rooted").

You should put the file somewhere else - such as the external storage. (If the adb shell is allowed to create directories under /data/local/tmp you might be able to create one there and chmod or chown it to give your app access, but that's non-portable across versions)

Or if you are merely trying to expose it, change the access permissions (someone will probably come along and point out the java constant for setting a file world readable is superficially deprecated, but actual disabling the capability would require a drastic change to the underlying operating system)