platform_bootable_recovery/etc/init.rc
Doug Zongker 075ad800c5 sideload without holding the whole package in RAM
Implement a new method of sideloading over ADB that does not require
the entire package to be held in RAM (useful for low-RAM devices and
devices using block OTA where we'd rather have more RAM available for
binary patching).

We communicate with the host using a new adb service called
"sideload-host", which makes the host act as a server, sending us
different parts of the package file on request.

We create a FUSE filesystem that creates a virtual file
"/sideload/package.zip" that is backed by the ADB connection -- users
see a normal file, but when they read from the file we're actually
fetching the data from the adb host.  This file is then passed to the
verification and installation systems like any other.

To prevent a malicious adb host implementation from serving different
data to the verification and installation phases of sideloading, the
FUSE filesystem verifies that the contents of the file don't change
between reads -- every time we fetch a block from the host we compare
its hash to the previous hash for that block (if it was read before)
and cause the read to fail if it changes.

One necessary change is that the minadbd started by recovery in
sideload mode no longer drops its root privileges (they're needed to
mount the FUSE filesystem).  We rely on SELinux enforcement to
restrict the set of things that can be accessed.

Change-Id: Ida7dbd3b04c1d4e27a2779d88c1da0c7c81fb114
2014-07-02 12:16:36 -07:00

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import /init.recovery.${ro.hardware}.rc
on early-init
# Apply strict SELinux checking of PROT_EXEC on mmap/mprotect calls.
write /sys/fs/selinux/checkreqprot 0
# Set the security context for the init process.
# This should occur before anything else (e.g. ueventd) is started.
setcon u:r:init:s0
start ueventd
start healthd
on init
export PATH /sbin:/system/bin
export ANDROID_ROOT /system
export ANDROID_DATA /data
export EXTERNAL_STORAGE /sdcard
symlink /system/etc /etc
mkdir /sdcard
mkdir /system
mkdir /data
mkdir /cache
mkdir /sideload
mount tmpfs tmpfs /tmp
chown root shell /tmp
chmod 0775 /tmp
write /proc/sys/kernel/panic_on_oops 1
on fs
mkdir /dev/usb-ffs 0770 shell shell
mkdir /dev/usb-ffs/adb 0770 shell shell
mount functionfs adb /dev/usb-ffs/adb uid=2000,gid=2000
write /sys/class/android_usb/android0/enable 0
write /sys/class/android_usb/android0/idVendor 18D1
write /sys/class/android_usb/android0/idProduct D001
write /sys/class/android_usb/android0/f_ffs/aliases adb
write /sys/class/android_usb/android0/functions adb
write /sys/class/android_usb/android0/iManufacturer ${ro.product.manufacturer}
write /sys/class/android_usb/android0/iProduct ${ro.product.model}
write /sys/class/android_usb/android0/iSerial ${ro.serialno}
on boot
ifup lo
hostname localhost
domainname localdomain
class_start default
# Load properties from /system/ + /factory after fs mount.
on load_all_props_action
load_all_props
# Mount filesystems and start core system services.
on late-init
trigger early-fs
trigger fs
trigger post-fs
trigger post-fs-data
# Load properties from /system/ + /factory after fs mount. Place
# this in another action so that the load will be scheduled after the prior
# issued fs triggers have completed.
trigger load_all_props_action
trigger early-boot
trigger boot
on property:sys.powerctl=*
powerctl ${sys.powerctl}
service ueventd /sbin/ueventd
critical
seclabel u:r:ueventd:s0
service healthd /sbin/healthd -r
critical
seclabel u:r:healthd:s0
service recovery /sbin/recovery
seclabel u:r:recovery:s0
service adbd /sbin/adbd --root_seclabel=u:r:su:s0 --device_banner=recovery
disabled
socket adbd stream 660 system system
seclabel u:r:adbd:s0
# Always start adbd on userdebug and eng builds
on property:ro.debuggable=1
write /sys/class/android_usb/android0/enable 1
start adbd
# Restart adbd so it can run as root
on property:service.adb.root=1
write /sys/class/android_usb/android0/enable 0
restart adbd
write /sys/class/android_usb/android0/enable 1