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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "UsbMidiDeviceJNI"
     18 #define LOG_NDEBUG 0
     19 #include "utils/Log.h"
     20 
     21 #include "jni.h"
     22 #include "JNIHelp.h"
     23 #include "android_runtime/AndroidRuntime.h"
     24 #include "android_runtime/Log.h"
     25 
     26 #include <stdio.h>
     27 #include <errno.h>
     28 #include <asm/byteorder.h>
     29 #include <sys/types.h>
     30 #include <sys/stat.h>
     31 #include <fcntl.h>
     32 #include <sys/ioctl.h>
     33 #include <sound/asound.h>
     34 
     35 namespace android
     36 {
     37 
     38 static jclass sFileDescriptorClass;
     39 static jfieldID sPipeFDField;
     40 
     41 static jint
     42 android_server_UsbMidiDevice_get_subdevice_count(JNIEnv *env, jobject /* thiz */,
     43         jint card, jint device)
     44 {
     45     char    path[100];
     46 
     47     snprintf(path, sizeof(path), "/dev/snd/controlC%d", card);
     48     int fd = open(path, O_RDWR);
     49     if (fd < 0) {
     50         ALOGE("could not open %s", path);
     51         return 0;
     52     }
     53 
     54     struct snd_rawmidi_info info;
     55     memset(&info, 0, sizeof(info));
     56     info.device = device;
     57     int ret = ioctl(fd, SNDRV_CTL_IOCTL_RAWMIDI_INFO, &info);
     58     close(fd);
     59 
     60     if (ret < 0) {
     61         ALOGE("SNDRV_CTL_IOCTL_RAWMIDI_INFO failed, errno: %d path: %s", errno, path);
     62         return -1;
     63     }
     64 
     65     ALOGD("subdevices_count: %d", info.subdevices_count);
     66     return info.subdevices_count;
     67 }
     68 
     69 static jobjectArray
     70 android_server_UsbMidiDevice_open(JNIEnv *env, jobject thiz, jint card, jint device,
     71         jint subdevice_count)
     72 {
     73     char    path[100];
     74 
     75     snprintf(path, sizeof(path), "/dev/snd/midiC%dD%d", card, device);
     76 
     77     // allocate one extra file descriptor for close pipe
     78     jobjectArray fds = env->NewObjectArray(subdevice_count + 1, sFileDescriptorClass, NULL);
     79     if (!fds) {
     80         return NULL;
     81     }
     82 
     83     // to support multiple subdevices we open the same file multiple times
     84     for (int i = 0; i < subdevice_count; i++) {
     85         int fd = open(path, O_RDWR);
     86         if (fd < 0) {
     87             ALOGE("open failed on %s for index %d", path, i);
     88             return NULL;
     89         }
     90 
     91         jobject fileDescriptor = jniCreateFileDescriptor(env, fd);
     92         env->SetObjectArrayElement(fds, i, fileDescriptor);
     93         env->DeleteLocalRef(fileDescriptor);
     94     }
     95 
     96     // create a pipe to use for unblocking our input thread
     97     int pipeFD[2];
     98     pipe(pipeFD);
     99     jobject fileDescriptor = jniCreateFileDescriptor(env, pipeFD[0]);
    100     env->SetObjectArrayElement(fds, subdevice_count, fileDescriptor);
    101     env->DeleteLocalRef(fileDescriptor);
    102     // store our end of the pipe in mPipeFD
    103     env->SetIntField(thiz, sPipeFDField, pipeFD[1]);
    104 
    105     return fds;
    106 }
    107 
    108 static void
    109 android_server_UsbMidiDevice_close(JNIEnv *env, jobject thiz, jobjectArray fds)
    110 {
    111     // write to mPipeFD to unblock input thread
    112     jint pipeFD = env->GetIntField(thiz, sPipeFDField);
    113     write(pipeFD, &pipeFD, sizeof(pipeFD));
    114     close(pipeFD);
    115     env->SetIntField(thiz, sPipeFDField, -1);
    116 
    117     int count = env->GetArrayLength(fds);
    118     for (int i = 0; i < count; i++) {
    119         jobject fd = env->GetObjectArrayElement(fds, i);
    120         close(jniGetFDFromFileDescriptor(env, fd));
    121     }
    122 }
    123 
    124 static JNINativeMethod method_table[] = {
    125     { "nativeGetSubdeviceCount", "(II)I", (void*)android_server_UsbMidiDevice_get_subdevice_count },
    126     { "nativeOpen", "(III)[Ljava/io/FileDescriptor;", (void*)android_server_UsbMidiDevice_open },
    127     { "nativeClose", "([Ljava/io/FileDescriptor;)V", (void*)android_server_UsbMidiDevice_close },
    128 };
    129 
    130 int register_android_server_UsbMidiDevice(JNIEnv *env)
    131 {
    132     jclass clazz = env->FindClass("java/io/FileDescriptor");
    133     if (clazz == NULL) {
    134         ALOGE("Can't find java/io/FileDescriptor");
    135         return -1;
    136     }
    137     sFileDescriptorClass = (jclass)env->NewGlobalRef(clazz);
    138 
    139     clazz = env->FindClass("com/android/server/usb/UsbMidiDevice");
    140     if (clazz == NULL) {
    141         ALOGE("Can't find com/android/server/usb/UsbMidiDevice");
    142         return -1;
    143     }
    144     sPipeFDField = env->GetFieldID(clazz, "mPipeFD", "I");
    145     if (sPipeFDField == NULL) {
    146         ALOGE("Can't find UsbMidiDevice.mPipeFD");
    147         return -1;
    148     }
    149 
    150     return jniRegisterNativeMethods(env, "com/android/server/usb/UsbMidiDevice",
    151             method_table, NELEM(method_table));
    152 }
    153 
    154 };
    155