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Commit 6d319b8a authored by Jerry Zhang's avatar Jerry Zhang
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Write descriptors for Mtp in UsbService 

The current model for setting up a functionfs
function is:

UsbDeviceManager#setCurrentFunctions() ->
intent is sent to MtpReceiver to write the descriptors ->
init/hal waits for descriptors to write, then pulls up gadget ->
Gadget is configured, a USB_STATE intent starts MtpServer

The main downside of this is a lack of reliability because
the Mtp process could be killed at any point. Normally, a
gadget is unbound if its control endpoint is closed. no_disconnect
works around this, but is still a little janky. In addition, the
extra intent delays the startup of the gadget.

With the new model, UsbDeviceManager writes the descriptors
on initialization. Since it is a system service, it won't be killed.

UsbDeviceManager#setCurrentFunctions() ->
init/hal pulls up gadget ->
Gadget is configured, a USB_STATE intent starts MtpServer
MtpServer calls UsbManager#getControlFd to get a dup of the control
endpoint.

Also modify permissions so system server can access mtp files.

Bug: 72877174
Test: Change usb configurations to ptp/mtp
Change-Id: Id17d2b5930f4e1f37ec1b4f00add9d594174ad49
parent c7f6eadf

core/java/android/hardware/usb/IUsbManager.aidl

+6 −0
Original line number Diff line number Diff line
@@ -105,6 +105,12 @@ interface IUsbManager 
    /* Gets the current screen unlocked functions. */

    long getScreenUnlockedFunctions();



    /* Get the functionfs control handle for the given function. Usb

     * descriptors will already be written, and the handle will be

     * ready to use.

     */

    ParcelFileDescriptor getControlFd(long function);



    /* Allow USB debugging from the attached host. If alwaysAllow is true, add the

     * the public key to list of host keys that the user has approved.

     */

core/java/android/hardware/usb/UsbManager.java

+19 −8
Original line number Diff line number Diff line
@@ -191,14 +191,6 @@ public class UsbManager { 
     */

    public static final String USB_DATA_UNLOCKED = "unlocked";



    /**

     * Boolean extra indicating whether the intent represents a change in the usb

     * configuration (as opposed to a state update).

     *

     * {@hide}

     */

    public static final String USB_CONFIG_CHANGED = "config_changed";



    /**

     * A placeholder indicating that no USB function is being specified.

     * Used for compatibility with old init scripts to indicate no functions vs. charging function.
@@ -470,6 +462,25 @@ public class UsbManager { 
        }

    }



    /**

     * Gets the functionfs control file descriptor for the given function, with

     * the usb descriptors and strings already written. The file descriptor is used

     * by the function implementation to handle events and control requests.

     *

     * @param function to get control fd for. Currently {@link #FUNCTION_MTP} and

     * {@link #FUNCTION_PTP} are supported.

     * @return A ParcelFileDescriptor holding the valid fd, or null if the fd was not found.

     *

     * {@hide}

     */

    public ParcelFileDescriptor getControlFd(long function) {

        try {

            return mService.getControlFd(function);

        } catch (RemoteException e) {

            throw e.rethrowFromSystemServer();

        }

    }



    /**

     * Returns true if the caller has permission to access the device.

     * Permission might have been granted temporarily via

core/java/com/android/internal/os/ZygoteInit.java

+1 −1
Original line number Diff line number Diff line
@@ -652,7 +652,7 @@ public class ZygoteInit { 
        String args[] = {

            "--setuid=1000",

            "--setgid=1000",

            "--setgroups=1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,1021,1023,1032,1065,3001,3002,3003,3006,3007,3009,3010",

            "--setgroups=1001,1002,1003,1004,1005,1006,1007,1008,1009,1010,1018,1021,1023,1024,1032,1065,3001,3002,3003,3006,3007,3009,3010",

            "--capabilities=" + capabilities + "," + capabilities,

            "--nice-name=system_server",

            "--runtime-args",

media/java/android/mtp/MtpServer.java

+5 −0
Original line number Diff line number Diff line
@@ -18,6 +18,8 @@ package android.mtp; 


import com.android.internal.util.Preconditions;



import java.io.FileDescriptor;



/**

 * Java wrapper for MTP/PTP support as USB responder.

 * {@hide}
@@ -34,6 +36,7 @@ public class MtpServer implements Runnable { 


    public MtpServer(

            MtpDatabase database,

            FileDescriptor controlFd,

            boolean usePtp,

            Runnable onTerminate,

            String deviceInfoManufacturer,
@@ -44,6 +47,7 @@ public class MtpServer implements Runnable { 
        mOnTerminate = Preconditions.checkNotNull(onTerminate);

        native_setup(

                database,

                controlFd,

                usePtp,

                deviceInfoManufacturer,

                deviceInfoModel,
@@ -92,6 +96,7 @@ public class MtpServer implements Runnable { 
    public static native final void native_configure(boolean usePtp);

    private native final void native_setup(

            MtpDatabase database,

            FileDescriptor controlFd,

            boolean usePtp,

            String deviceInfoManufacturer,

            String deviceInfoModel,

media/jni/android_mtp_MtpServer.cpp

+6 −12
Original line number Diff line number Diff line
@@ -55,22 +55,17 @@ static inline MtpServer* getMtpServer(JNIEnv *env, jobject thiz) { 
    return (MtpServer*)env->GetLongField(thiz, field_MtpServer_nativeContext);

}



static void android_mtp_configure(JNIEnv *, jobject, jboolean usePtp) {

    MtpServer::configure(usePtp);

}



static void

android_mtp_MtpServer_setup(JNIEnv *env, jobject thiz, jobject javaDatabase, jboolean usePtp,

        jstring deviceInfoManufacturer,

        jstring deviceInfoModel,

        jstring deviceInfoDeviceVersion,

        jstring deviceInfoSerialNumber)

android_mtp_MtpServer_setup(JNIEnv *env, jobject thiz, jobject javaDatabase, jobject jControlFd,

        jboolean usePtp, jstring deviceInfoManufacturer, jstring deviceInfoModel,

        jstring deviceInfoDeviceVersion, jstring deviceInfoSerialNumber)

{

    const char *deviceInfoManufacturerStr = env->GetStringUTFChars(deviceInfoManufacturer, NULL);

    const char *deviceInfoModelStr = env->GetStringUTFChars(deviceInfoModel, NULL);

    const char *deviceInfoDeviceVersionStr = env->GetStringUTFChars(deviceInfoDeviceVersion, NULL);

    const char *deviceInfoSerialNumberStr = env->GetStringUTFChars(deviceInfoSerialNumber, NULL);

    MtpServer* server = new MtpServer(getMtpDatabase(env, javaDatabase),

    int controlFd = dup(jniGetFDFromFileDescriptor(env, jControlFd));

    MtpServer* server = new MtpServer(getMtpDatabase(env, javaDatabase), controlFd,

            usePtp,

            MtpString((deviceInfoManufacturerStr != NULL) ? deviceInfoManufacturerStr : ""),

            MtpString((deviceInfoModelStr != NULL) ? deviceInfoModelStr : ""),
@@ -201,8 +196,7 @@ android_mtp_MtpServer_remove_storage(JNIEnv *env, jobject thiz, jint storageId) 
// ----------------------------------------------------------------------------



static const JNINativeMethod gMethods[] = {

    {"native_configure",              "(Z)V",  (void *)android_mtp_configure},

    {"native_setup",                "(Landroid/mtp/MtpDatabase;ZLjava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V",

    {"native_setup",                "(Landroid/mtp/MtpDatabase;Ljava/io/FileDescriptor;ZLjava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V",

                                            (void *)android_mtp_MtpServer_setup},

    {"native_run",                  "()V",  (void *)android_mtp_MtpServer_run},

    {"native_cleanup",              "()V",  (void *)android_mtp_MtpServer_cleanup},