Android官方資料--Configuration Examples

IN THIS DOCUMENT

Below are examples of external storage configurations for various device types. Only the relevant portions of the configuration files are included.

Due to configuration changes in Android 6.0 (like the removal of thestorage_list.xmlresource overlay), the configuration examples are split into two categories.

Android 5.x and earlier

Physical primary only

This is a typical configuration for a device with single external storage device which is a physical SD card, like Nexus One.

The raw physical device must first be mounted under/mnt/media_rwwhere only the system and FUSE daemon can access it.voldwill then manage thefuse_sdcard0service when media is inserted/removed.

fstab.hardware

[physical device node] auto vfat defaults voldmanaged=sdcard0:auto,noemulatedsd

init.hardware.rc

on init
  mkdir /mnt/media_rw/sdcard0 0700 media_rw media_rw
  mkdir /storage/sdcard0 0700 root root
  export EXTERNAL_STORAGE /storage/sdcard0
service fuse_sdcard0 /system/bin/sdcard -u 1023 -g 1023 -d /mnt/media_rw/sdcard0 /storage/sdcard0
  class late_start
  disabled

storage_list.xml

Emulated primary only

This is a typical configuration for a device with single external storage device which is backed by internal storage on the device, like Nexus 4.

init.hardware.rc

on init
  mkdir /mnt/shell/emulated 0700 shell shell
  mkdir /storage/emulated 0555 root root
  export EXTERNAL_STORAGE /storage/emulated/legacy
  export EMULATED_STORAGE_SOURCE /mnt/shell/emulated
  export EMULATED_STORAGE_TARGET /storage/emulated
on fs
  setprop ro.crypto.fuse_sdcard true
service sdcard /system/bin/sdcard -u 1023 -g 1023 -l /data/media /mnt/shell/emulated
  class late_start

storage_list.xml

Emulated primary, physical secondary

This is a typical configuration for a device with multiple external storage devices, where the primary device is backed by internal storage on the device, and where the secondary device is a physical SD card, like Xoom.

The raw physical device must first be mounted under/mnt/media_rwwhere only the system and FUSE daemon can access it.voldwill then manage thefuse_sdcard1service when media is inserted/removed.

fstab.hardware

[physical device node] auto vfat defaults voldmanaged=sdcard1:auto

init.hardware.rc

on init
  mkdir /mnt/shell/emulated 0700 shell shell
  mkdir /storage/emulated 0555 root root
  mkdir /mnt/media_rw/sdcard1 0700 media_rw media_rw
  mkdir /storage/sdcard1 0700 root root
  export EXTERNAL_STORAGE /storage/emulated/legacy
  export EMULATED_STORAGE_SOURCE /mnt/shell/emulated
  export EMULATED_STORAGE_TARGET /storage/emulated
  export SECONDARY_STORAGE /storage/sdcard1
on fs
  setprop ro.crypto.fuse_sdcard true
service sdcard /system/bin/sdcard -u 1023 -g 1023 -l /data/media /mnt/shell/emulated
  class late_start
service fuse_sdcard1 /system/bin/sdcard -u 1023 -g 1023 -w 1023 -d /mnt/media_rw/sdcard1 /storage/sdcard1
  class late_start
  disabled

storage_list.xml

Android 6.0

Physical primary only

This is a typical configuration for a device with single external storage device which is a physical SD card, like the original Android One. There is no secondary shared storage and the device cannot support multi-user.

fstab.device

/devices/platform/mtk-msdc.1/mmc_host*     auto    auto    defaults
voldmanaged=sdcard0:auto,encryptable=userdata,noemulatedsd

init.device.rc

on init
  # By default, primary storage is physical
  setprop ro.vold.primary_physical 1
  

Emulated primary only

This is a typical configuration for a device with single external storage device which is backed by internal storage on the device, like Nexus 6.

• Primary shared storage (/sdcard) is emulated on top of internal storage.
• No secondary SD card storage.
• USB OTG storage devices supported.
• Supports multi-user.

fstab.device

/devices/*/xhci-hcd.0.auto/usb*       auto      auto  defaults
                          voldmanaged=usb:auto

Emulated primary, physical secondary

This is a typical configuration for a device with multiple external storage devices, where the primary device is backed by internal storage on the device, and where the secondary device is a physical SD card, like Xoom.

• Primary shared storage (/sdcard) is emulated on top of internal storage.
• Secondary storage is a physical SD card slot that can be adopted.
• Supports multi-user.

fstab.device

/devices/platform/mtk-msdc.1/mmc_host*      auto   auto   defaults
voldmanaged=sdcard1:auto,encryptable=userdata