The fuse data provider for adb/sdcard shares common code and structures.
This cl creates a FuseDataProvider base class and provides
implementations for adb and sdcard.
In the follow cls, we can kill the provider_vtab struct; and also add
another implementation to parse a block map file and provides data.
Test: unit tests pass, sideload a package, apply a package from sdcard
Change-Id: If8311666a52a2e3c0fbae0ee9688fa6d01e4ad09
For applying update from SD card, we used to use a thread to serve the
file with fuse. Since accessing through fuse involves going from kernel
to userspace to kernel, it may run into deadlock (e.g. for mmap_sem)
when a page fault occurs. Switch to using a process instead.
Bug: 23783099
Bug: 26313124
Change-Id: Iac0f55b1bdb078cadb520cfe1133e70fbb26eadd
Make a fuse filesystem that sits on top of the selected package file
on the sdcard, so we can verify that the file contents don't change
while being read and avoid copying the file to /tmp (that is, RAM)
before verifying and installing it.
Change-Id: Ifd982aa68bfe469eda5f839042648654bf7386a1
