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Commit 84954030 authored by Tomasz Wasilczyk's avatar Tomasz Wasilczyk
Browse files

Implement struct printing 

Also:
- fix potential use-after-free in nlbuf iterator
- simplify getFirst usage by migrating from std::optional to std::pair

Bug: 161898189
Test: print all messages from RTMGRP_LINK group

Change-Id: I4aa785ccef60e397ba87088f37e35d9873fc3c82
parent 2aa1a124

automotive/can/1.0/default/libnetdevice/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ cc_library_static { 
        "protocols/generic/Unknown.cpp",

        "protocols/route/Link.cpp",

        "protocols/route/Route.cpp",

        "protocols/route/structs.cpp",

        "protocols/MessageDefinition.cpp",

        "protocols/NetlinkProtocol.cpp",

        "protocols/all.cpp",

automotive/can/1.0/default/libnetdevice/include/libnetdevice/nlbuf.h

+13 −6
Original line number Diff line number Diff line
@@ -66,9 +66,12 @@ class nlbuf { 
        return mData;

    }



    std::optional<std::reference_wrapper<const T>> getFirst() const {

        if (!ok()) return std::nullopt;

        return *mData;

    std::pair<bool, const T&> getFirst() const {

        if (!ok()) {

            static const T dummy = {};

            return {false, dummy};

        }

        return {true, *mData};

    }



    /**
@@ -141,7 +144,7 @@ class nlbuf { 
        size_t len() const { return mBuffer.remainingLength(); }



      private:

        const nlbuf<T>& mBuffer;

        const nlbuf<T> mBuffer;

    };



    raw_view getRaw() const { return {*this}; }
@@ -160,8 +163,12 @@ class nlbuf { 
    size_t declaredLength() const {

        // We can't even fit a header, so let's return some absurd high value to trip off

        // buffer overflow checks.

        if (sizeof(T) > remainingLength()) return std::numeric_limits<size_t>::max() / 2;

        return declaredLengthImpl();

        static constexpr size_t badHeaderLength = std::numeric_limits<size_t>::max() / 2;



        if (sizeof(T) > remainingLength()) return badHeaderLength;

        const auto len = declaredLengthImpl();

        if (sizeof(T) > len) return badHeaderLength;

        return len;

    }



    size_t remainingLength() const {

automotive/can/1.0/default/libnetdevice/printer.cpp

+9 −5
Original line number Diff line number Diff line
@@ -85,17 +85,16 @@ static void toStream(std::stringstream& ss, const nlbuf<nlattr> attr, 


    ss << attrtype.name << ": ";

    switch (attrtype.dataType) {

        case DataType::Raw: {

        case DataType::Raw:

            toStream(ss, attr.data<uint8_t>());

            break;

        }

        case DataType::Nested: {

            ss << '{';

            bool first = true;

            for (auto childattr : attr.data<nlattr>()) {

            for (const auto childattr : attr.data<nlattr>()) {

                if (!first) ss << ", ";

                first = false;

                toStream(ss, childattr, attrtype.subTypes);

                toStream(ss, childattr, std::get<protocols::AttributeMap>(attrtype.ops));

            }

            ss << '}';

            break;
@@ -105,9 +104,14 @@ static void toStream(std::stringstream& ss, const nlbuf<nlattr> attr, 
            ss << '"' << sanitize({str.ptr(), str.len()}) << '"';

            break;

        }

        case DataType::Uint: {

        case DataType::Uint:

            ss << attr.data<uint32_t>().copyFirst();

            break;

        case DataType::Struct: {

            const auto structToStream =

                    std::get<protocols::AttributeDefinition::ToStream>(attrtype.ops);

            structToStream(ss, attr);

            break;

        }

    }

}

automotive/can/1.0/default/libnetdevice/protocols/MessageDefinition.h

+7 −4
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 


#include <map>

#include <sstream>

#include <variant>



namespace android::netdevice::protocols {
@@ -57,11 +58,13 @@ struct AttributeDefinition { 
        Nested,

        String,

        Uint,

        Struct,

    };

    using ToStream = std::function<void(std::stringstream& ss, const nlbuf<nlattr> attr)>;



    std::string name;

    DataType dataType = DataType::Raw;

    AttributeMap subTypes = {};

    std::variant<AttributeMap, ToStream> ops = AttributeMap{};

};



/**
@@ -107,13 +110,13 @@ class MessageDefinition : public MessageDescriptor { 
        : MessageDescriptor(name, messageTypes, attrTypes, sizeof(T)) {}



    void dataToStream(std::stringstream& ss, const nlbuf<nlmsghdr> hdr) const override {

        const auto msg = hdr.data<T>().getFirst();

        if (!msg.has_value()) {

        const auto& [ok, msg] = hdr.data<T>().getFirst();

        if (!ok) {

            ss << "{incomplete payload}";

            return;

        }



        toStream(ss, *msg);

        toStream(ss, msg);

    }



  protected:

automotive/can/1.0/default/libnetdevice/protocols/generic/Ctrl.cpp

+4 −4
Original line number Diff line number Diff line
@@ -37,14 +37,14 @@ Ctrl::Ctrl() : GenericMessageBase(GENL_ID_CTRL, "ID_CTRL", { 
    {CTRL_ATTR_VERSION, {"VERSION", DataType::Uint}},

    {CTRL_ATTR_HDRSIZE, {"HDRSIZE", DataType::Uint}},

    {CTRL_ATTR_MAXATTR, {"MAXATTR", DataType::Uint}},

    {CTRL_ATTR_OPS, {"OPS", DataType::Nested, {

        {std::nullopt, {"OP", DataType::Nested, {

    {CTRL_ATTR_OPS, {"OPS", DataType::Nested, AttributeMap{

        {std::nullopt, {"OP", DataType::Nested, AttributeMap{

            {CTRL_ATTR_OP_ID, {"ID", DataType::Uint}},

            {CTRL_ATTR_OP_FLAGS, {"FLAGS", DataType::Uint}},

        }}},

    }}},

    {CTRL_ATTR_MCAST_GROUPS, {"MCAST_GROUPS", DataType::Nested, {

        {std::nullopt, {"GRP", DataType::Nested, {

    {CTRL_ATTR_MCAST_GROUPS, {"MCAST_GROUPS", DataType::Nested, AttributeMap{

        {std::nullopt, {"GRP", DataType::Nested, AttributeMap{

            {CTRL_ATTR_MCAST_GRP_NAME, {"NAME", DataType::String}},

            {CTRL_ATTR_MCAST_GRP_ID, {"ID", DataType::Uint}},

        }}},