RASCSI/src/raspberrypi/protobuf_util.cpp

//---------------------------------------------------------------------------
//
// SCSI Target Emulator RaSCSI (*^..^*)
// for Raspberry Pi
//
// Copyright (C) 2021 Uwe Seimet
//
//---------------------------------------------------------------------------

#include <unistd.h>
#include "os.h"
#include "log.h"
#include "rascsi_interface.pb.h"
#include "localizer.h"
#include "exceptions.h"
#include "protobuf_util.h"

using namespace std;
using namespace rascsi_interface;

#define FPRT(fp, ...) fprintf(fp, __VA_ARGS__ )

#define COMPONENT_SEPARATOR ':'
#define KEY_VALUE_SEPARATOR '='

Localizer localizer;

void protobuf_util::ParseParameters(PbDeviceDefinition& device, const string& params)
{
	if (!params.empty()) {
		if (params.find(KEY_VALUE_SEPARATOR) != string::npos) {
			stringstream ss(params);
			string p;
			while (getline(ss, p, COMPONENT_SEPARATOR)) {
				if (!p.empty()) {
					size_t separator_pos = p.find(KEY_VALUE_SEPARATOR);
					if (separator_pos != string::npos) {
						AddParam(device, p.substr(0, separator_pos), p.substr(separator_pos + 1));
					}
				}
			}
		}
		// Old style parameters, for backwards compatibility only.
		// Only one of these parameters will be used by rascsi, depending on the device type.
		else {
			AddParam(device, "file", params);
			if (params != "bridge" && params != "daynaport" && params != "printer" && params != "services") {
				AddParam(device, "interfaces", params);
			}
		}
    }
}

const string protobuf_util::GetParam(const PbCommand& command, const string& key)
{
	auto map = command.params();
	return map[key];
}

const string protobuf_util::GetParam(const PbDeviceDefinition& device, const string& key)
{
	auto map = device.params();
	return map[key];
}

void protobuf_util::AddParam(PbCommand& command, const string& key, const string& value)
{
	if (!key.empty() && !value.empty()) {
		auto& map = *command.mutable_params();
		map[key] = value;
	}
}

void protobuf_util::AddParam(PbDevice& device, const string& key, const string& value)
{
	if (!key.empty() && !value.empty()) {
		auto& map = *device.mutable_params();
		map[key] = value;
	}
}

void protobuf_util::AddParam(PbDeviceDefinition& device, const string& key, const string& value)
{
	if (!key.empty() && !value.empty()) {
		auto& map = *device.mutable_params();
		map[key] = value;
	}
}

//---------------------------------------------------------------------------
//
//	Serialize/Deserialize protobuf message: Length followed by the actual data.
//  Little endian is assumed.
//
//---------------------------------------------------------------------------

void protobuf_util::SerializeMessage(int fd, const google::protobuf::Message& message)
{
	string data;
	message.SerializeToString(&data);

	// Write the size of the protobuf data as a header
    int32_t size = data.length();
    if (write(fd, &size, sizeof(size)) != sizeof(size)) {
    	throw io_exception("Can't write protobuf message header");
    }

    // Write the actual protobuf data
    if (write(fd, data.data(), size) != size) {
    	throw io_exception("Can't write protobuf message data");
    }
}

void protobuf_util::DeserializeMessage(int fd, google::protobuf::Message& message)
{
	// Read the header with the size of the protobuf data
	uint8_t header_buf[4];
	int bytes_read = ReadNBytes(fd, header_buf, sizeof(header_buf));
	if (bytes_read < (int)sizeof(header_buf)) {
		return;
	}
	int32_t size = (header_buf[3] << 24) + (header_buf[2] << 16) + (header_buf[1] << 8) + header_buf[0];
	if (size <= 0) {
		throw io_exception("Broken protobuf message header");
	}

	// Read the binary protobuf data
	uint8_t data_buf[size];
	bytes_read = ReadNBytes(fd, data_buf, size);
	if (bytes_read < size) {
		throw io_exception("Missing protobuf message data");
	}

	// Create protobuf message
	string data((const char *)data_buf, size);
	message.ParseFromString(data);
}

int protobuf_util::ReadNBytes(int fd, uint8_t *buf, int n)
{
	int offset = 0;
	while (offset < n) {
		ssize_t len = read(fd, buf + offset, n - offset);
		if (!len) {
			break;
		}

		offset += len;
	}

	return offset;
}

bool protobuf_util::ReturnLocalizedError(const CommandContext& context, const LocalizationKey key,
		const string& arg1, const string& arg2, const string& arg3)
{
	return ReturnLocalizedError(context, key, NO_ERROR_CODE, arg1, arg2, arg3);
}

bool protobuf_util::ReturnLocalizedError(const CommandContext& context, const LocalizationKey key,
		const PbErrorCode error_code, const string& arg1, const string& arg2, const string& arg3)
{
	// For the logfile always use English
	LOGERROR("%s", localizer.Localize(key, "en", arg1, arg2, arg3).c_str());

	return ReturnStatus(context, false, localizer.Localize(key, context.locale, arg1, arg2, arg3), error_code, false);
}

bool protobuf_util::ReturnStatus(const CommandContext& context, bool status, const string& msg,
		const PbErrorCode error_code, bool log)
{
	// Do not log twice if logging has already been done in the localized error handling above
	if (log && !status && !msg.empty()) {
		LOGERROR("%s", msg.c_str());
	}

	if (context.fd == -1) {
		if (!msg.empty()) {
			if (status) {
				FPRT(stderr, "Error: ");
				FPRT(stderr, "%s", msg.c_str());
				FPRT(stderr, "\n");
			}
			else {
				FPRT(stdout, "%s", msg.c_str());
				FPRT(stderr, "\n");
			}
		}
	}
	else {
		PbResult result;
		result.set_status(status);
		result.set_error_code(error_code);
		result.set_msg(msg);
		SerializeMessage(context.fd, result);
	}

	return status;
}