Also this is outside the realm of the SDK (running as the system user is *way* outside the realm of the SDK), so would best be asked on an appropriate group like android-porting.
On Fri, Nov 5, 2010 at 9:12 AM, Chris Stratton <cs07...@gmail.com> wrote: > You cannot read USB devices anyway as android does not, without > platform modifications, support USB host mode. > > You can of course read the SD card when it is *not* mounted over USB > to an external computer but is instead mounted locally by android, > provided that your application is not running as the system uid. > > You should not need the system uid to *read* files under /system/lib - > indeed, a lot of them are already memory mapped into your application > when it is forked off of zygote. However, you should be aware that > with few exceptions most of those files are considered unstable, > private APIs and so should not be directly utilized by your > application but only by intermediate java layers of the platform which > present the public APIs to you. > > If for some reason you really needed to be the system uid and also to > access the SD card, you would need to either use inter process > communication between something that is the system uid and something > that isn't which is accessing the SD card, modify the platform to > remove the restriction on the SD card and the system UID, or run as a > privileged user other than the system uid. > > On Nov 5, 11:32 am, xhy <xhyg...@gmail.com> wrote: > > Thank you sir，I want to visit the file which is under the > /system/lib,But > > at the same time,I also want to read the USB device.So what can i do ? > > > > 2010/11/5 Chris Stratton <cs07...@gmail.com> > > > > > > > > > If the sdcard gets unmounted, any process with an open file handle to > > > it gets killed. > > > > > Letting the system process be killed was considered a bad thing. To > > > avoid that, the system process (which is to say any system process) is > > > not allowed to access the SD card. > > > > > FYI, you probably will not be able to install your apk with the system > > > uid on most secured devices, unless you are in possession of the > > > system certificate for the devices on which you want to deploy. > > > > > What exactly do you need to access in the /system folder? You do know > > > it's mounted read-only, right? > > > > > Technically, anything regarding the system folder is beyond the bounds > > > of discussion of android-developers which is supposed to be confined > > > to the SDK APIs. > > > > > On Nov 4, 10:57 pm, xhy <xhyg...@gmail.com> wrote: > > > > Hi all,Now I come across a question,I want to visit the system folder > in > > > the > > > > android file system.So i add the > > > "android:SharedUserId=android.uid.system" > > > > in the manifest.xml,But I can not visit the USB device if that. > > > > > > -- > > > > Hongyue Xu > > > > > -- > > > 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<android-developers%2bunsubscr...@googlegroups.com> > <android-developers%2bunsubscr...@googlegroups.com<android-developers%252bunsubscr...@googlegroups.com> > > > > > For more options, visit this group at > > >http://groups.google.com/group/android-developers?hl=en > > > > -- > > Hongyue Xu > > -- > 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<android-developers%2bunsubscr...@googlegroups.com> > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > -- Dianne Hackborn Android framework engineer hack...@android.com Note: please don't send private questions to me, as I don't have time to provide private support, and so won't reply to such e-mails. All such questions should be posted on public forums, where I and others can see and answer them. -- 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
