117 lines
3.5 KiB
Plaintext
117 lines
3.5 KiB
Plaintext
libusb for Android
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==================
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Building:
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---------
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To build libusb for Android do the following:
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1. Download the latest NDK from:
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http://developer.android.com/tools/sdk/ndk/index.html
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2. Extract the NDK.
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3. Open a shell and make sure there exist an NDK global variable
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set to the directory where you extracted the NDK.
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4. Change directory to libusb's "android/jni"
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5. Run "$NDK/ndk-build".
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The libusb library, examples and tests can then be found in:
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"android/libs/$ARCH"
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Where $ARCH is one of:
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armeabi
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armeabi-v7a
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mips
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mips64
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x86
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x86_64
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Installing:
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-----------
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If you wish to use libusb from native code in own Android application
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then you should add the following line to your Android.mk file:
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include $(PATH_TO_LIBUSB_SRC)/android/jni/libusb.mk
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You will then need to add the following lines to the build
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configuration for each native binary which uses libusb:
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LOCAL_C_INCLUDES += $(LIBUSB_ROOT_ABS)
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LOCAL_SHARED_LIBRARIES += libusb1.0
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The Android build system will then correctly include libusb in the
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application package (APK) file, provided ndk-build is invoked before
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the package is built.
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For a rooted device it is possible to install libusb into the system
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image of a running device:
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1. Enable ADB on the device.
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2. Connect the device to a machine running ADB.
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3. Execute the following commands on the machine
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running ADB:
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# Make the system partition writable
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adb shell su -c "mount -o remount,rw /system"
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# Install libusb
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adb push obj/local/armeabi/libusb1.0.so /sdcard/
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adb shell su -c "cat > /system/lib/libusb1.0.so < /sdcard/libusb1.0.so"
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adb shell rm /sdcard/libusb1.0.so
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# Install the samples and tests
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for B in listdevs fxload xusb sam3u_benchmark hotplugtest stress
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do
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adb push "obj/local/armeabi/$B" /sdcard/
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adb shell su -c "cat > /system/bin/$B < /sdcard/$B"
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adb shell su -c "chmod 0755 /system/bin/$B"
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adb shell rm "/sdcard/$B"
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done
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# Make the system partition read only again
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adb shell su -c "mount -o remount,ro /system"
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# Run listdevs to
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adb shell su -c "listdevs"
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4. If your device only has a single OTG port then ADB can generally
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be switched to using Wifi with the following commands when connected
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via USB:
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adb shell netcfg
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# Note the wifi IP address of the phone
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adb tcpip 5555
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# Use the IP address from netcfg
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adb connect 192.168.1.123:5555
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Runtime Permissions:
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--------------------
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The default system configuration on most Android device will not allow
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access to USB devices. There are several options for changing this.
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If you have control of the system image then you can modify the
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ueventd.rc used in the image to change the permissions on
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/dev/bus/usb/*/*. If using this approach then it is advisable to
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create a new Android permission to protect access to these files.
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It is not advisable to give all applications read and write permissions
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to these files.
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For rooted devices the code using libusb could be executed as root
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using the "su" command. An alternative would be to use the "su" command
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to change the permissions on the appropriate /dev/bus/usb/ files.
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Users have reported success in using android.hardware.usb.UsbManager
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to request permission to use the UsbDevice and then opening the
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device. The difficulties in this method is that there is no guarantee
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that it will continue to work in the future Android versions, it
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requires invoking Java APIs and running code to match each
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android.hardware.usb.UsbDevice to a libusb_device.
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