[Recovery]自动挂载system分区

// bootable/recovery/recovery.cpp
case Device::MOUNT_SYSTEM:
    char system_root_image[PROPERTY_VALUE_MAX];
    property_get("ro.build.system_root_image", system_root_image, "");

    // For a system image built with the root directory (i.e.
    // system_root_image == "true"), we mount it to /system_root, and symlink /system
    // to /system_root/system to make adb shell work (the symlink is created through
    // the build system).
    // Bug: 22855115
    if (strcmp(system_root_image, "true") == 0) {
        if (ensure_path_mounted_at("/", "/system_root") != -1) {
            ui->Print("Mounted /system.\n");
        }
    } else {
        if (ensure_path_mounted("/system") != -1) {
            ui->Print("Mounted /system.\n");
        }
    }

    break;

mvim /bootable/recovery/etc/init.rc

import /init.recovery.${ro.hardware}.rc

on early-init
    # Set the security context of /postinstall if present.
    restorecon /postinstall

    start ueventd
    start healthd

on init
    export ANDROID_ROOT /system
    export ANDROID_DATA /data
    export EXTERNAL_STORAGE /sdcard

    symlink /system/etc /etc

    mkdir /sdcard
    mkdir /udisk
    mkdir /system
    mkdir /data
    mkdir /cache
    mkdir /sideload
    mkdir /firmware
    mount tmpfs tmpfs /tmp

    chown root shell /tmp
    chmod 0775 /tmp

    write /proc/sys/kernel/panic_on_oops 1
    write /proc/sys/vm/max_map_count 1000000

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}

mvim /device/qcom/xxxx/imit.target.rc

on fs
	wait /dev/block/bootdevice
	mount_all fstab.qcom
	write /proc/sys/vm/swappiness 100

# Android fstab file.
# The filesystem that contains the filesystem checker binary (typically /system) cannot
# specify MF_CHECK, and must come before any filesystems that do specify MF_CHECK

#TODO: Add 'check' as fs_mgr_flags with data partition.
# Currently we dont have e2fsck compiled. So fs check would failed.

#<src>                                                <mnt_point>  <type>  <mnt_flags and options>                     <fs_mgr_flags>
/dev/block/bootdevice/by-name/system         /system      ext4    ro,barrier=1,discard                                wait, verify
/dev/block/bootdevice/by-name/userdata       /data        ext4    nosuid,nodev,barrier=1,noauto_da_alloc,discard      wait,forceencrypt=footer
/devices/soc/7864900.sdhci/mmc_host*        /storage/sdcard1   vfat    nosuid,nodev         wait,voldmanaged=sdcard1:auto,noemulatedsd,encryptable=footer
/devices/soc/78db000.usb/msm_hsusb_host*    /storage/usbotg    vfat    nosuid,nodev         wait,voldmanaged=usbotg:auto
/dev/block/bootdevice/by-name/config         /frp  emmc    defaults                                            defaults
/dev/block/bootdevice/by-name/misc          /misc              emmc    defaults             defaults

wait /dev/block/bootdevice/by-name/system
mount ext4 /dev/block/bootdevice/by-name/system /system wait rw barrier=1