Changed to modern serial library and more logging

simonvetter · munnik · Oct 2, 2024 · Oct 2, 2024 · Oct 2, 2024 · Oct 3, 2024
commit 6d03bac3321f30f590dea1d96ab0690408a26a77
diff --git a/client.go b/client.go
@@ -10,17 +10,15 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"go.bug.st/serial"
 )
 
 type RegType uint
 type Endianness uint
 type WordOrder uint
 
 const (
-	PARITY_NONE uint = 0
-	PARITY_EVEN uint = 1
-	PARITY_ODD  uint = 2
-
 	HOLDING_REGISTER RegType = 0
 	INPUT_REGISTER   RegType = 1
 
@@ -39,13 +37,13 @@ type ClientConfiguration struct {
 	// <mode>://<serial device or host:port> e.g. tcp://plc:502
 	URL string
 	// Speed sets the serial link speed (in bps, rtu only)
-	Speed uint
+	Speed int
 	// DataBits sets the number of bits per serial character (rtu only)
-	DataBits uint
+	DataBits int
 	// Parity sets the serial link parity mode (rtu only)
-	Parity uint
+	Parity serial.Parity
 	// StopBits sets the number of serial stop bits (rtu only)
-	StopBits uint
+	StopBits serial.StopBits
 	// Timeout sets the request timeout value
 	Timeout time.Duration
 	// TLSClientCert sets the client-side TLS key pair (tcp+tls only)
@@ -106,12 +104,10 @@ func NewClient(conf *ClientConfiguration) (mc *ModbusClient, err error) {
 			mc.conf.DataBits = 8
 		}
 
-		if mc.conf.StopBits == 0 {
-			if mc.conf.Parity == PARITY_NONE {
-				mc.conf.StopBits = 2
-			} else {
-				mc.conf.StopBits = 1
-			}
+		if mc.conf.Parity == serial.NoParity {
+			mc.conf.StopBits = serial.TwoStopBits
+		} else {
+			mc.conf.StopBits = serial.OneStopBit
 		}
 
 		if mc.conf.Timeout == 0 {
@@ -594,21 +590,31 @@ func (mc *ModbusClient) WriteCoil(addr uint16, value bool) (err error) {
 	// validate the response code
 	switch {
 	case res.functionCode == req.functionCode:
-		// expect 4 bytes (2 byte of address + 2 bytes of value)
-		if len(res.payload) != 4 ||
-			// bytes 1-2 should be the coil address
-			bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr ||
-			// bytes 3-4 should either be {0xff, 0x00} or {0x00, 0x00}
-			// depending on the coil value
-			(value == true && res.payload[2] != 0xff) ||
-			res.payload[3] != 0x00 {
+		if len(res.payload) != 4 {
+			err = ErrProtocolError
+			mc.logger.Warningf("the length of the payload is not 4 but %d", len(res.payload))
+			return
+		}
+		if bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr {
 			err = ErrProtocolError
+			mc.logger.Warningf("bytes 1-2 are not the expected coil address %d, but %d", addr, bytesToUint16(BIG_ENDIAN, res.payload[0:2]))
+			return
+		}
+		if value && (res.payload[2] != 0xff || res.payload[3] != 0x00) {
+			err = ErrProtocolError
+			mc.logger.Warningf("expected % x but got % x", []byte{0xff, 0x00}, res.payload[2:4])
+			return
+		}
+		if !value && (res.payload[2] != 0x00 || res.payload[3] != 0x00) {
+			err = ErrProtocolError
+			mc.logger.Warningf("expected % x but got % x", []byte{0x00, 0x00}, res.payload[2:4])
 			return
 		}
 
 	case res.functionCode == (req.functionCode | 0x80):
 		if len(res.payload) != 1 {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected the length of the payload to be 1, but the length is %d", len(res.payload))
 			return
 		}
 
@@ -677,19 +683,26 @@ func (mc *ModbusClient) WriteCoils(addr uint16, values []bool) (err error) {
 	// validate the response code
 	switch {
 	case res.functionCode == req.functionCode:
-		// expect 4 bytes (2 byte of address + 2 bytes of quantity)
-		if len(res.payload) != 4 ||
-			// bytes 1-2 should be the base coil address
-			bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr ||
-			// bytes 3-4 should be the quantity of coils
-			bytesToUint16(BIG_ENDIAN, res.payload[2:4]) != quantity {
+		if len(res.payload) != 4 {
+			err = ErrProtocolError
+			mc.logger.Warningf("the length of the payload is not 4 but %d", len(res.payload))
+			return
+		}
+		if bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr {
+			err = ErrProtocolError
+			mc.logger.Warningf("bytes 1-2 are not the expected coil address %d, but %d", addr, bytesToUint16(BIG_ENDIAN, res.payload[0:2]))
+			return
+		}
+		if bytesToUint16(BIG_ENDIAN, res.payload[2:4]) != quantity {
 			err = ErrProtocolError
+			mc.logger.Warningf("bytes 3-4 are not the expected quantity of coils %d, but %d", quantity, bytesToUint16(BIG_ENDIAN, res.payload[2:4]))
 			return
 		}
 
 	case res.functionCode == (req.functionCode | 0x80):
 		if len(res.payload) != 1 {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected the length of the payload to be 1, but the length is %d", len(res.payload))
 			return
 		}
 
@@ -731,19 +744,26 @@ func (mc *ModbusClient) WriteRegister(addr uint16, value uint16) (err error) {
 	// validate the response code
 	switch {
 	case res.functionCode == req.functionCode:
-		// expect 4 bytes (2 byte of address + 2 bytes of value)
-		if len(res.payload) != 4 ||
-			// bytes 1-2 should be the register address
-			bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr ||
-			// bytes 3-4 should be the value
-			bytesToUint16(mc.endianness, res.payload[2:4]) != value {
+		if len(res.payload) != 4 {
+			err = ErrProtocolError
+			mc.logger.Warningf("the length of the payload is not 4 but %d", len(res.payload))
+			return
+		}
+		if bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr {
 			err = ErrProtocolError
+			mc.logger.Warningf("bytes 1-2 are not the expected coil address %d, but %d", addr, bytesToUint16(BIG_ENDIAN, res.payload[0:2]))
+			return
+		}
+		if bytesToUint16(mc.endianness, res.payload[2:4]) != value {
+			err = ErrProtocolError
+			mc.logger.Warningf("bytes 3-4 are not the expected value %d, but %d", value, bytesToUint16(mc.endianness, res.payload[2:4]))
 			return
 		}
 
 	case res.functionCode == (req.functionCode | 0x80):
 		if len(res.payload) != 1 {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected the length of the payload to be 1, but the length is %d", len(res.payload))
 			return
 		}
 
@@ -986,12 +1006,14 @@ func (mc *ModbusClient) readBools(addr uint16, quantity uint16, di bool) (values
 
 		if len(res.payload) != expectedLen {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected the length of the payload to be %d, but the length is %d", expectedLen, len(res.payload))
 			return
 		}
 
 		// validate the byte count field
 		if int(res.payload[0])+1 != expectedLen {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected %d in the byte count field, but got %d", expectedLen, int(res.payload[0])+1)
 			return
 		}
 
@@ -1001,6 +1023,7 @@ func (mc *ModbusClient) readBools(addr uint16, quantity uint16, di bool) (values
 	case res.functionCode == (req.functionCode | 0x80):
 		if len(res.payload) != 1 {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected the length of the payload to be 1, but the length is %d", len(res.payload))
 			return
 		}
 
@@ -1074,13 +1097,15 @@ func (mc *ModbusClient) readRegisters(addr uint16, quantity uint16, regType RegT
 		// (1 byte of length + 2 bytes per register)
 		if len(res.payload) != 1+2*int(quantity) {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected the length of the payload to be %d, but the length is %d", 1+2*int(quantity), len(res.payload))
 			return
 		}
 
 		// validate the byte count field
 		// (2 bytes per register * number of registers)
 		if uint(res.payload[0]) != 2*uint(quantity) {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected %d in the byte count field, but got %d", 2*uint(quantity), int(res.payload[0]))
 			return
 		}
 
@@ -1090,13 +1115,29 @@ func (mc *ModbusClient) readRegisters(addr uint16, quantity uint16, regType RegT
 	case res.functionCode == (req.functionCode | 0x80):
 		if len(res.payload) != 1 {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected the length of the payload to be 1, but the length is %d", len(res.payload))
 			return
 		}
 
 		err = mapExceptionCodeToError(res.payload[0])
 
 	default:
-		err = ErrProtocolError
+		if len(res.payload) != 4 {
+			err = ErrProtocolError
+			mc.logger.Warningf("the length of the payload is not 4 but %d", len(res.payload))
+			return
+		}
+		if bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr {
+			err = ErrProtocolError
+			mc.logger.Warningf("bytes 1-2 are not the expected coil address %d, but %d", addr, bytesToUint16(BIG_ENDIAN, res.payload[0:2]))
+			return
+		}
+		if bytesToUint16(BIG_ENDIAN, res.payload[2:4]) != quantity {
+			err = ErrProtocolError
+			mc.logger.Warningf("bytes 3-4 are not the expected quantity of coils %d, but %d", quantity, bytesToUint16(BIG_ENDIAN, res.payload[2:4]))
+			return
+		}
+
 		mc.logger.Warningf("unexpected response code (%v)", res.functionCode)
 	}
 
@@ -1159,19 +1200,26 @@ func (mc *ModbusClient) writeRegisters(addr uint16, values []byte) (err error) {
 	// validate the response code
 	switch {
 	case res.functionCode == req.functionCode:
-		// expect 4 bytes (2 byte of address + 2 bytes of quantity)
-		if len(res.payload) != 4 ||
-			// bytes 1-2 should be the base register address
-			bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr ||
-			// bytes 3-4 should be the quantity of registers (2 bytes per register)
-			bytesToUint16(BIG_ENDIAN, res.payload[2:4]) != quantity {
+		if len(res.payload) != 4 {
+			err = ErrProtocolError
+			mc.logger.Warningf("the length of the payload is not 4 but %d", len(res.payload))
+			return
+		}
+		if bytesToUint16(BIG_ENDIAN, res.payload[0:2]) != addr {
+			err = ErrProtocolError
+			mc.logger.Warningf("bytes 1-2 are not the expected coil address %d, but %d", addr, bytesToUint16(BIG_ENDIAN, res.payload[0:2]))
+			return
+		}
+		if bytesToUint16(BIG_ENDIAN, res.payload[2:4]) != quantity {
 			err = ErrProtocolError
+			mc.logger.Warningf("bytes 3-4 are not the expected value %d, but %d", quantity, bytesToUint16(mc.endianness, res.payload[2:4]))
 			return
 		}
 
 	case res.functionCode == (req.functionCode | 0x80):
 		if len(res.payload) != 1 {
 			err = ErrProtocolError
+			mc.logger.Warningf("expected the length of the payload to be 1, but the length is %d", len(res.payload))
 			return
 		}
 

diff --git a/cmd/modbus-cli.go b/cmd/modbus-cli.go
@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/simonvetter/modbus"
+	"go.bug.st/serial"
 )
 
 func main() {
@@ -24,10 +25,10 @@ func main() {
 	var certPath string // path to TLS client certificate
 	var keyPath string  // path to TLS client key
 	var clientKeyPair tls.Certificate
-	var speed uint
-	var dataBits uint
+	var speed int
+	var dataBits int
 	var parity string
-	var stopBits uint
+	var stopBits string
 	var endianness string
 	var wordOrder string
 	var timeout string
@@ -37,10 +38,10 @@ func main() {
 	var runList []operation
 
 	flag.StringVar(&target, "target", "", "target device to connect to (e.g. tcp://somehost:502) [required]")
-	flag.UintVar(&speed, "speed", 19200, "serial bus speed in bps (rtu)")
-	flag.UintVar(&dataBits, "data-bits", 8, "number of bits per character on the serial bus (rtu)")
+	flag.IntVar(&speed, "speed", 19200, "serial bus speed in bps (rtu)")
+	flag.IntVar(&dataBits, "data-bits", 8, "number of bits per character on the serial bus (rtu)")
 	flag.StringVar(&parity, "parity", "none", "parity bit <none|even|odd> on the serial bus (rtu)")
-	flag.UintVar(&stopBits, "stop-bits", 2, "number of stop bits <0|1|2>) on the serial bus (rtu)")
+	flag.StringVar(&stopBits, "stop-bits", "2", "number of stop bits <0|1|1.5|2>) on the serial bus (rtu)")
 	flag.StringVar(&timeout, "timeout", "3s", "timeout value")
 	flag.StringVar(&endianness, "endianness", "big", "register endianness <little|big>")
 	flag.StringVar(&wordOrder, "word-order", "highfirst", "word ordering for 32-bit registers <highfirst|hf|lowfirst|lf>")
@@ -66,21 +67,32 @@ func main() {
 		URL:      target,
 		Speed:    speed,
 		DataBits: dataBits,
-		StopBits: stopBits,
 	}
 
 	switch parity {
 	case "none":
-		config.Parity = modbus.PARITY_NONE
+		config.Parity = serial.NoParity
 	case "odd":
-		config.Parity = modbus.PARITY_ODD
+		config.Parity = serial.OddParity
 	case "even":
-		config.Parity = modbus.PARITY_EVEN
+		config.Parity = serial.EvenParity
 	default:
 		fmt.Printf("unknown parity setting '%s' (should be one of none, odd or even)\n",
 			parity)
 		os.Exit(1)
 	}
+	switch stopBits {
+	case "1":
+		config.StopBits = serial.OneStopBit
+	case "1.5":
+		config.StopBits = serial.OnePointFiveStopBits
+	case "2":
+		config.StopBits = serial.TwoStopBits
+	default:
+		fmt.Printf("unknown stop-bits setting '%s' (should be one of 1, 1.5 or 2)\n",
+			stopBits)
+		os.Exit(1)
+	}
 
 	config.Timeout, err = time.ParseDuration(timeout)
 	if err != nil {

diff --git a/go.mod b/go.mod
@@ -2,4 +2,7 @@ module github.com/simonvetter/modbus
 
 go 1.16
 
-require github.com/goburrow/serial v0.1.0
+require (
+	go.bug.st/serial v1.6.2
+	golang.org/x/sys v0.25.0 // indirect
+)
diff --git a/go.sum b/go.sum
@@ -1,2 +1,18 @@
-github.com/goburrow/serial v0.1.0 h1:v2T1SQa/dlUqQiYIT8+Cu7YolfqAi3K96UmhwYyuSrA=
-github.com/goburrow/serial v0.1.0/go.mod h1:sAiqG0nRVswsm1C97xsttiYCzSLBmUZ/VSlVLZJ8haA=
+github.com/creack/goselect v0.1.2 h1:2DNy14+JPjRBgPzAd1thbQp4BSIihxcBf0IXhQXDRa0=
+github.com/creack/goselect v0.1.2/go.mod h1:a/NhLweNvqIYMuxcMOuWY516Cimucms3DglDzQP3hKY=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+go.bug.st/serial v1.6.2 h1:kn9LRX3sdm+WxWKufMlIRndwGfPWsH1/9lCWXQCasq8=
+go.bug.st/serial v1.6.2/go.mod h1:UABfsluHAiaNI+La2iESysd9Vetq7VRdpxvjx7CmmOE=
+golang.org/x/sys v0.0.0-20220829200755-d48e67d00261 h1:v6hYoSR9T5oet+pMXwUWkbiVqx/63mlHjefrHmxwfeY=
+golang.org/x/sys v0.0.0-20220829200755-d48e67d00261/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
+golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=