packages.xml is the package manager's persistent state. Only the package manager should write it, and you are likely to break the system if you modify it yourself (or have your changes wiped away the next time the package manager writes it). If you want to know more about it, you can look at PackageManagerService.java.
2009/5/6 倪旭东 <[email protected]> > Hi, > Still some questions: > 1. Does packages.xml (in /data/system ) has real effect in the check > procedure of "reference monitor"? I do some experiment on the emulator: > Modify some App's permissions' profile, it does not have effect of app's > execute. It is the problem of emulator or the acctual effect file is not > this one. > > 2. In the packages.xml file, the user-developed app's permissions are list > in every packages, > but for the system bulid-in app, such as phone, it does not provide the > related permissions, > How the system to determine its permissions. > > 3. Form the packmanager() we can get some information about permissions, > what is relationship between packages.xml. It reads it from this file? > > Thanks. > > regards, > xudong > > > > 2009/5/5 William Enck <[email protected]> > >> Xudong, >> >> On May 5, 2009, at 12:59 PM, 倪旭东 wrote: >> >> Thank you. I still have some questions: >> 1. After the installation, the app's related permissions files is saved in >> the same .apk file or saved in a system central file? >> >> >> Take a look at /data/system/packages.xml >> >> 2. At runtime, I learned that there is a "reference monitor" from the >> paper Understanding Android >> Security<http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4768640&arnumber=4768655>to >> check the permission lable. Which is the source code for this "reference >> monitor", or it's a vitual concept. I wonder to know which parts of source >> code dealing with this function. Thanks. >> >> >> We described it more as a "virtual concept". There isn't code >> directly corresponding to a reference monitor, but the Activity Manager >> (frameworks/base/services/java/com/android/server/am/ActivityManagerService.java) >> is >> a good place to start looking. >> >> -Will >> >> -- >> William Enck >> PhD Candidate >> Department of Computer Science and Engineering >> The Pennsylvania State University >> [email protected] >> >> > -- Dianne Hackborn Android framework engineer [email protected] 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.
