Android HAL HIDL

1 Android HAL HIDL
HIDL是Treble Interface的一部分。

1.1 GNSS和Sensors
Refer to gnss and sensors
hardware/interfaces/gnss/1.0/default
hardware/interfaces/sensors/1.0/default

1.2 产生HAL框架步骤
1）生成androidmk和hidl-gen
在Android项目根目录下：

. build/envsetup.sh
lunch
make blueprint_tools
make hidl-gen
make c2hal // 将传统HAL .h头文件转换成hidl .hal文件工具

2）产生.cpp和.h文件
mkdir -p hardware/interfaces/oem1/1.0/default
路径中出现的1.0表示HAL当前版本

仿照GNSS或者Sensors增加一个IOem1.hal
in hardware/interfaces/oem1/1.0/IOem1.hal

在Android项目源码根目录下编写脚本my_oem1.sh，调用hidl-gen产生.cpp和.h文件
in my_oem1.sh
[email protected]
LOC=hardware/interfaces/oem1/1.0/default
hidl-gen -o $LOC -Lc++-impl -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport $PACKAGE
hidl-gen -o $LOC -Landroidbp-impl -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport $PACKAGE

执行：
./my_oem1.sh

3）产生.bp和.mk文件
执行：
./hardware/interfaces/update-makefiles.sh

4）
编译最终在out/target/common/gen/JAVA_LIBRARIES目录下生成Java源文件。 

1.3 mk文件转换为bp文件
. build/envsetup.sh
make blueprint_tools
androidmk Android.mk > Android.bp

1.4 生成Android.mk模版
LOCAL_PROPRIETARY_MODULE := true
LOCAL_MODULE_RELATIVE_PATH := hw

generate-android-mk
https://github.com/WanghongLin/generate-android-mk

2 VNDK

3 VTS测试步骤
1) 安装必须的python工具和adb - Linux需要
apt-get install android-tools-adb

2) 
source build/envsetup.sh
lunch
make vts

3) 编译完成后
in out/host/linux-x86/vts/
$cd android-vts/tools
$vts-tradefed
> run vts
or
> run vts-hal
or
> run vts-kernel

如果要在Windows上测试，需要将文件夹android-vts拷贝到windows下  - 待完善

4) 测试完成后
查看测试结果
android-vts/results
android-vts/logs

4 Android中查看有哪些HIDL HAL
adb root
adb shell
# lshal

5 Android打印C++调用栈
#include  
在需要打印的地方加如下的定义。
android::CallStack stack("oem");

logcat | grep oem

6 LinkToDeath
6.1 Principle
Client很容易监控Service的died；但是Service监控Client的died，需要Client实现使用IBinder接口的ICallback，传给Service，然后Service可以监控这个使用IBinder接口的ICallback的died，这样就实现了监控Client的died。

1）一个BpBinder可以注册多个死亡回调；但Kernel只允许注册一个死亡通知（ref->death只能为空或者指向一个指针）
2）BC_REQUEST_DEATH_NOTIFICATION - linkToDeath()
3）BC_CLEAR_DEATH_NOTIFICATION - unlinkToDeath()
4）当process exit时会触发系统关闭该进程已经打开的文件节点/dev/hwbinder，从而调用binder_node_release()；通知died - BINDER_WORK_DEAD_BINDER
5）
echo 0x18 > /sys/module/binder/parameters/debug_mask
dmesg -C
dmesg -w | grep binder &
kill -9 $PID
6）ftrace as shown below
echo 0 > /d/tracing/tracing_on
echo nop > /d/tracing/current_tracer

echo function_graph > /d/tracing/current_tracer
#echo function > /d/tracing/current_tracer
echo funcgraph-proc > /d/tracing/trace_options

echo binder_cleanup_ref_olocked > /d/tracing/set_graph_function
echo 1 > /d/tracing/tracing_on

cat /d/tracing/trace

debuggerd -b $PID

6.2 代码实施
6.2.1 JAVA实施步骤
import android.os.IHwBinder.DeathRecipient;

private class xxxDeathRecipient implements DeathRecipient {
    @Override
    public void serviceDied(long cookie) {
        Log.i(TAG, "serviceDied, re-connect XXX");
        if (xxxService != null) {
            xxxService.unlinkToDeath(this);
        }

        // TODO: 重连service
    }
};
xxxDeathRecipient mxxxDeathRecipient = new xxxDeathRecipient();

获取xxxService成功后：
try {
    xxxService.linkToDeath(mxxxDeathRecipient, 0);
} catch (RemoteException e) {
    e.printStackTrace();
}

6.2.2 CPP实施步骤
using android::hardware::hidl_death_recipient;

class MyDeathRecipient : public android::hardware::hidl_death_recipient {
    virtual void serviceDied(uint64_t cookie, const android::wp<::android::hidl::base::V1_0::IBase>& who) {
        // Deal with the fact that the service died
    }
}
MyDeathRecipient mDeathRecipient = new MyDeathRecipient();

获取xxxService成功后：
xxxService->linkToDeath(mDeathRecipient, 0);

7 strace解析binder驱动数据插件
7.1 知识
A进程给B进程发送数据：A进程使用BC_TRANSACTION发送，经过binder驱动转换，B进程接收到是BR_TRANSACTION
B进程给A进程回复数据：B进程使用BC_REPLY发送，经过binder驱动转换，A进程接收到是BR_REPLY。

7.2 代码
#include "defs.h"
#include

static inline unsigned int get_my_le32(const unsigned char *p)
{
    return p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24;
}

static const char *cmd_to_str(unsigned int cmd)
{
    switch(cmd) {
        case BC_TRANSACTION:
            return "BC_TRANSACTION";
            break;
        case BC_REPLY:
            return "BC_REPLY";
            break;
        case BR_TRANSACTION:
            return "BR_TRANSACTION";
            break;
        case BR_REPLY:
            return "BR_REPLY";
            break;
    }
    return "UNDEFINED";
}

/*
 * bc: binder command, from userland to driver
 * br: binder return, from driver to userland
 */
static void handle_bx_transaction(struct tcb *const tcp,
        struct binder_write_read *bwr,
        struct binder_transaction_data *txn)
{
    binder_size_t   txn_data_size = 0;
    binder_size_t   txn_offsets_size = 0;
#if defined (FEATURE_PRINT_DETAIL)
    int n = 0;
    unsigned char buf[256], buf_offsets[256];
#else
    binder_uintptr_t    txn_buffer;
    binder_uintptr_t    txn_offsets;
#endif

    txn_data_size = txn->data_size;
    txn_offsets_size = txn->offsets_size;
    tprintf("handle=%d, ptr=%llx, target_cookie=0x%llx,\n"
            "code=%d, flags=0x%02x, sender_pid=%d, sender_euid=%d",
            txn->target.handle, txn->target.ptr, txn->cookie,
            txn->code,
            txn->flags,
            txn->sender_pid,
            txn->sender_euid);
    if (txn_data_size <= 8) {
        tprintf(", data_size=%llu, %02x %02x %02x %02x %02x %02x %02x %02x\n",
                txn_data_size,
                txn->data.buf[0], txn->data.buf[1],
                txn->data.buf[2], txn->data.buf[3],
                txn->data.buf[4], txn->data.buf[5],
                txn->data.buf[6], txn->data.buf[7]);
    } else {
#if defined (FEATURE_PRINT_DETAIL)
        txn_data_size = (txn_data_size > 256) ? 256 : txn_data_size;
        if (umoven(tcp, txn->data.ptr.buffer, txn_data_size, buf) < 0)
            return;
        txn_offsets_size = (txn_offsets_size > 256) ? 256 : txn_offsets_size;
        if (umoven(tcp, txn->data.ptr.offsets, txn_offsets_size, buf_offsets) < 0)
            return;

        for (; n < (txn_offsets_size / sizeof(binder_size_t)); n++)
        {
            struct flat_binder_object* pbinder =
                (struct flat_binder_object*)((char*)buf +
                        ((int*)(buf_offsets))[n]);

            unsigned long type = pbinder->type;
            switch (type)
            {
                case BINDER_TYPE_BINDER:
                case BINDER_TYPE_WEAK_BINDER:
                    tprintf("binder=0x%llx, cookie=0x%llx\n",
                            pbinder->binder, pbinder->cookie);
                    break;

                case BINDER_TYPE_HANDLE:
                case BINDER_TYPE_WEAK_HANDLE:
                    tprintf("handle=0x%08x\n", pbinder->handle);
                    break;
                default:
                    break;
            }
        }
#else
        txn_buffer = txn->data.ptr.buffer;
        txn_offsets = txn->data.ptr.offsets;
        tprintf(", \ndata_size=%llu, txn_buffer=0x%llx\n",
                txn_data_size, txn_buffer);
        dumpstr(tcp, (long) txn_buffer, txn_data_size);

        tprintf("\noffsets_size=%llu, txn_offsets=0x%llx\n",
                txn_offsets_size, txn_offsets);
        dumpstr(tcp, (long) txn_offsets, txn_offsets_size);
#endif
    }
}

/*
 * mRemote.transact(GET_SERVICE_TRANSACTION, data, reply, 0);
 * GET_SERVICE_TRANSACTION <-> struct binder_transaction_data.code
 * data                    <-> struct binder_transaction_data.data
 *
 * write_bufer: CMD + binder_transaction_data + CMD + binder_transaction_data...
 * byte 0-3: command, offset0 - nr, offset1 - magic 'c' = 0x63
 * byte 4-7: target
 *
 * read_bufer: BR_NOOP + CMD + binder_transaction_data + CMD + binder_transaction_data...
 * byte 0-3:  BR_NOOP, 0c 72 00 00, offset0 - nr, offset1 - magic 'r' = 0x72
 *
 */
static void decode_bwr(struct tcb *const tcp, const kernel_ulong_t addr)
{
    struct binder_write_read bwr;
    struct binder_transaction_data *txn;
    int read_len, write_len, offset;
    unsigned char buf[256], *p;
    unsigned int cmd, cmd_data_len;
    static int ioctl_count = 1;

    if (umove_or_printaddr(tcp, addr, &bwr))
        return;
    if (abbrev(tcp)) {
        tprints(", ");
        tprintf("{BC_TRANS=0x%08x, BR_REPLY=0x%08x, "
                "write_size=%llu, write_consumed=%llu, "
                "read_size=%llu, read_consumed=%llu}",
                BC_TRANSACTION, BR_REPLY,
                bwr.write_size, bwr.write_consumed,
                bwr.read_size, bwr.read_consumed);
        return;
    }

    /* VERBOSE mode */
    tprints(",\n");
    tprintf("%d) ############################## WRITE ###################################\n",
            ioctl_count++);
    tprintf("write_size=%llu, write_consumed=%llu, write_buffer=\n",
            bwr.write_size, bwr.write_consumed);

    write_len = (bwr.write_size > 256) ? 256 : bwr.write_size;
    if (umoven(tcp, bwr.write_buffer, write_len, buf) < 0)
        goto out;

    offset = 0;
    while (offset < write_len) {
        cmd = get_my_le32(buf + offset);
        cmd_data_len = _IOC_SIZE(cmd);

        switch (cmd) {
            case BC_TRANSACTION:
            case BC_REPLY:
                tprintf("%s--->\n", cmd_to_str(cmd));
                p = buf + offset + 4;
                txn = (struct binder_transaction_data *)p;
                handle_bx_transaction(tcp, &bwr, txn);
                break;
        }
        offset += (4 + cmd_data_len);
    }

    dumpstr(tcp, (long) bwr.write_buffer, bwr.write_size);
    tprints("\n");

    tprintf("%d) ############################## READ ###################################\n",
            ioctl_count++);
    tprintf("read_size=%llu, read_consumed=%llu,\n",
            bwr.read_size, bwr.read_consumed);
    read_len = (bwr.read_size > 256) ? 256 : bwr.read_size;
    if (umoven(tcp, bwr.read_buffer, read_len, buf) < 0)
        goto out;

    offset = 0;
    while (offset < read_len) {
        cmd = get_my_le32(buf + offset);
        cmd_data_len = _IOC_SIZE(cmd);

        switch (cmd) {
            case BR_TRANSACTION:
            case BR_REPLY:
                tprintf("%s--->\n", cmd_to_str(cmd));
                p = buf + offset + 4;
                txn = (struct binder_transaction_data *)p;
                handle_bx_transaction(tcp, &bwr, txn);
                break;
        }
        offset += (4 + cmd_data_len);
    }

    tprints("\n");
    dumpstr(tcp, (long) bwr.read_buffer, bwr.read_size);
out:
    tprints("}");
}

int binder_ioctl(struct tcb *const tcp, const unsigned int code,
        const kernel_ulong_t arg)
{
    switch (code) {
        case BINDER_WRITE_READ:
            decode_bwr(tcp, arg);
            break;

        default:
            return RVAL_DECODED;
    }
    return RVAL_DECODED | 1;
}

7.3 查看hwbinder的数据
ps -A| grep hwservicemanager
strace -tt -T -x -v -p $PID 2>&1 |grep -vE "writev|futex|getuid|ppoll"

8 Abbreviations
VTS：Vendor Test Suite