[android-developers] SharedUserId: Things that Cannot Change http://android-developers.blogspot.com/2011/06/things-that-cannot-change.html
Would SharedUserId be worth calling out. I currently don't have one set on any of my apps, but after playing around with the feature while trying to get a Test Project to run as the same user ... I think it's not really possible to change the user_id with a live app without some big issues. The only way I can think to do it is to release an apk which changes all elements in /data/data/* to be opened with Context.MODE_WORLD_WRITEABLE and then later in another apk release, change the sharedUserId to the value desired. This sounds pretty bad. My theory is based on just very primitive tests of upgrading from a debug build with no sharedUserId to a debug build of the same package (cert) and realizing that any attempt to read anything in the /data/data/my_package either throws a SecurityException or FileNotFoundException (even when writing a new file). I think this should really be called out in the documentation, similar to how package name has big bold letters around it all the time that says (DO NOT CHANGE!) :) However even with my idea of making a release with world writable files, I don't believe I would ever be able to create new files within /data/data/my_package. I am wondering that if the package name has to be unique anyways for the package manager, why they just didn't make the default user_id the package_name of the app. Then with the correct signing cert and agreed upon name you would be able to migrate to a userid if need be. ... Or am I completely wrong? -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] SharedUserId: Things that Cannot Change http://android-developers.blogspot.com/2011/06/things-that-cannot-change.html
On Mon, Jul 25, 2011 at 12:39 PM, Greg Giacovelli miyamo...@gmail.com wrote: Would SharedUserId be worth calling out. I currently don't have one set on any of my apps, but after playing around with the feature while trying to get a Test Project to run as the same user ... I think it's not really possible to change the user_id with a live app without some big issues. If sharedUserId was not set, and you set it afterwards, the UID of the app changes. I think it's mentioned somewhere in the docs, but can't seem to find the reference. So, basically, if you want to have two (or more) apps with a shared UID, you have to design for this in advance. E.g., release one app with sharedUserId=foo and the next one with the same. There is an open issue though: http://code.google.com/p/android/issues/detail?id=1227 However even with my idea of making a release with world writable files, I don't believe I would ever be able to create new files within /data/data/my_package. I am wondering that if the package name has to be unique anyways for the package manager, why they just didn't make the default user_id the package_name of the app. Then with the correct signing cert and agreed upon name you would be able to migrate to a userid if need be. ... Or am I completely wrong? Interesting proposition. It does seem that the system manages shared UIDs differently from 'regular' ones, so maybe that's the reason this hasn't been (can't?) be done? -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
