Compile and install libmodbus library under CentOS7
Compile and install libmodbus library under CentOS7###
Download libdmodbus source code##
The download page of libmodbus official website is shown below:
You can download the libmodbus source code from the following link
- libmodbus-3.1.6.tar.gz
- libmodbus-3.0.8.tar.gz
Of course, you can also clone the source code directly from github to the local
git clone https://github.com/stephane/libmodbus.git
The downloaded source code directory is shown below:
Compile and install lidmodbus
How to install libmodbus has been very clear above:
Run the following commands directly in the root directory of libmodbus to compile and install the libmodbus library
. /autogen.sh
. /configure
make
make install
The relevant compilation and installation process is shown in the following figure:
You can see that by default the header files of libmodbus are placed in the /usr/local/include directory, and the dynamic library files are placed in the /usr/local/lib directory.
At this point, libmodbus compilation and installation under CentOS7 is complete.
test##
Regarding some tests of libmodbus, Github also describes it more clearly:
Some test examples provided by libmodbus official website are shown below:
/*
* Copyright © 2008-2014 Stéphane Raimbault <[email protected]>
*
* SPDX-License-Identifier: BSD-3-Clause
* /
# include <stdio.h>
# include <unistd.h>
# include <string.h>
# include <stdlib.h>
# include <errno.h>
# include <modbus.h>
# ifdef _WIN32
# include <winsock2.h>
# else
# include <sys/socket.h>
# endif
/* For MinGW */
# ifndef MSG_NOSIGNAL
# define MSG_NOSIGNAL 0
# endif
# include "unit-test.h"enum{
TCP,
TCP_PI,
RTU
};
int main(int argc, char*argv[]){
int s =-1;
modbus_t *ctx;
modbus_mapping_t *mb_mapping;
int rc;
int i;
int use_backend;
uint8_t *query;
int header_length;if(argc >1){if(strcmp(argv[1],"tcp")==0){
use_backend = TCP;}elseif(strcmp(argv[1],"tcppi")==0){
use_backend = TCP_PI;}elseif(strcmp(argv[1],"rtu")==0){
use_backend = RTU;}else{printf("Usage:\n %s [tcp|tcppi|rtu] - Modbus server for unit testing\n\n", argv[0]);return-1;}}else{/* By default */
use_backend = TCP;}if(use_backend == TCP){
ctx =modbus_new_tcp("127.0.0.1",1502);
query =malloc(MODBUS_TCP_MAX_ADU_LENGTH);}elseif(use_backend == TCP_PI){
ctx =modbus_new_tcp_pi("::0","1502");
query =malloc(MODBUS_TCP_MAX_ADU_LENGTH);}else{
ctx =modbus_new_rtu("/dev/ttyUSB0",115200,'N',8,1);modbus_set_slave(ctx, SERVER_ID);
query =malloc(MODBUS_RTU_MAX_ADU_LENGTH);}
header_length =modbus_get_header_length(ctx);modbus_set_debug(ctx, TRUE);
mb_mapping =modbus_mapping_new_start_address(
UT_BITS_ADDRESS, UT_BITS_NB,
UT_INPUT_BITS_ADDRESS, UT_INPUT_BITS_NB,
UT_REGISTERS_ADDRESS, UT_REGISTERS_NB_MAX,
UT_INPUT_REGISTERS_ADDRESS, UT_INPUT_REGISTERS_NB);if(mb_mapping == NULL){fprintf(stderr,"Failed to allocate the mapping: %s\n",modbus_strerror(errno));modbus_free(ctx);return-1;}/* Examples from PI_MODBUS_300.pdf.
Only the read-only input values are assigned. *//* Initialize input values that's can be only done server side. */modbus_set_bits_from_bytes(mb_mapping->tab_input_bits,0, UT_INPUT_BITS_NB,
UT_INPUT_BITS_TAB);/* Initialize values of INPUT REGISTERS */for(i=0; i < UT_INPUT_REGISTERS_NB; i++){
mb_mapping->tab_input_registers[i]= UT_INPUT_REGISTERS_TAB[i];;}if(use_backend == TCP){
s =modbus_tcp_listen(ctx,1);modbus_tcp_accept(ctx,&s);}elseif(use_backend == TCP_PI){
s =modbus_tcp_pi_listen(ctx,1);modbus_tcp_pi_accept(ctx,&s);}else{
rc =modbus_connect(ctx);if(rc ==-1){fprintf(stderr,"Unable to connect %s\n",modbus_strerror(errno));modbus_free(ctx);return-1;}}for(;;){do{
rc =modbus_receive(ctx, query);/* Filtered queries return 0 */}while(rc ==0);/* The connection is not closed on errors which require on reply such as
bad CRC in RTU. */if(rc ==-1&& errno != EMBBADCRC){/* Quit */break;}/* Special server behavior to test client */if(query[header_length]==0x03){/* Read holding registers */if(MODBUS_GET_INT16_FROM_INT8(query, header_length +3)== UT_REGISTERS_NB_SPECIAL){printf("Set an incorrect number of values\n");MODBUS_SET_INT16_TO_INT8(query, header_length +3,
UT_REGISTERS_NB_SPECIAL -1);}elseif(MODBUS_GET_INT16_FROM_INT8(query, header_length +1)== UT_REGISTERS_ADDRESS_SPECIAL){printf("Reply to this special register address by an exception\n");modbus_reply_exception(ctx, query,
MODBUS_EXCEPTION_SLAVE_OR_SERVER_BUSY);continue;}elseif(MODBUS_GET_INT16_FROM_INT8(query, header_length +1)== UT_REGISTERS_ADDRESS_INVALID_TID_OR_SLAVE){const int RAW_REQ_LENGTH =5;
uint8_t raw_req[]={(use_backend == RTU)? INVALID_SERVER_ID :0xFF,0x03,0x02,0x00,0x00};printf("Reply with an invalid TID or slave\n");modbus_send_raw_request(ctx, raw_req, RAW_REQ_LENGTH *sizeof(uint8_t));continue;}elseif(MODBUS_GET_INT16_FROM_INT8(query, header_length +1)== UT_REGISTERS_ADDRESS_SLEEP_500_MS){printf("Sleep 0.5 s before replying\n");usleep(500000);}elseif(MODBUS_GET_INT16_FROM_INT8(query, header_length +1)== UT_REGISTERS_ADDRESS_BYTE_SLEEP_5_MS){/* Test low level only available in TCP mode *//* Catch the reply and send reply byte a byte */
uint8_t req[]="\x00\x1C\x00\x00\x00\x05\xFF\x03\x02\x00\x00";
int req_length =11;
int w_s =modbus_get_socket(ctx);if(w_s ==-1){fprintf(stderr,"Unable to get a valid socket in special test\n");continue;}/* Copy TID */
req[1]= query[1];for(i=0; i < req_length; i++){printf("(%.2X)", req[i]);usleep(5000);
rc =send(w_s,(const char*)(req + i),1, MSG_NOSIGNAL);if(rc ==-1){break;}}continue;}}
rc =modbus_reply(ctx, query, rc, mb_mapping);if(rc ==-1){break;}}printf("Quit the loop: %s\n",modbus_strerror(errno));if(use_backend == TCP){if(s !=-1){close(s);}}modbus_mapping_free(mb_mapping);free(query);/* For RTU */modbus_close(ctx);modbus_free(ctx);return0;}
/*
* Copyright © 2008-2014 Stéphane Raimbault <[email protected]>
*
* SPDX-License-Identifier: BSD-3-Clause
* /
# include <stdio.h>
# include <unistd.h>
# include <string.h>
# include <stdlib.h>
# include <errno.h>
# include <modbus.h>
# include "unit-test.h"const int EXCEPTION_RC =2;enum{
TCP,
TCP_PI,
RTU
};
int test_server(modbus_t *ctx, int use_backend);
int send_crafted_request(modbus_t *ctx, int function,
uint8_t *req, int req_size,
uint16_t max_value, uint16_t bytes,
int backend_length, int backend_offset);
int equal_dword(uint16_t *tab_reg,const uint32_t value);
# define BUG_REPORT(_cond, _format, _args ...) \
printf("\nLine %d: assertion error for '%s': " _format "\n", __LINE__, # _cond, ## _args)
# define ASSERT_TRUE(_cond, _format, __args...){ \
if(_cond){ \
printf("OK\n"); \
} else{ \
BUG_REPORT(_cond, _format, ## __args); \
goto close; \
} \
};
int equal_dword(uint16_t *tab_reg,const uint32_t value){return((tab_reg[0]==(value >>16))&&(tab_reg[1]==(value &0xFFFF)));}
int main(int argc, char *argv[]){const int NB_REPORT_SLAVE_ID =10;
uint8_t *tab_rp_bits = NULL;
uint16_t *tab_rp_registers = NULL;
uint16_t *tab_rp_registers_bad = NULL;
modbus_t *ctx = NULL;
int i;
uint8_t value;
int nb_points;
int rc;
float real;
uint32_t old_response_to_sec;
uint32_t old_response_to_usec;
uint32_t new_response_to_sec;
uint32_t new_response_to_usec;
uint32_t old_byte_to_sec;
uint32_t old_byte_to_usec;
int use_backend;
int success = FALSE;
int old_slave;if(argc >1){if(strcmp(argv[1],"tcp")==0){
use_backend = TCP;}elseif(strcmp(argv[1],"tcppi")==0){
use_backend = TCP_PI;}elseif(strcmp(argv[1],"rtu")==0){
use_backend = RTU;}else{printf("Usage:\n %s [tcp|tcppi|rtu] - Modbus client for unit testing\n\n", argv[0]);exit(1);}}else{/* By default */
use_backend = TCP;}if(use_backend == TCP){
ctx =modbus_new_tcp("127.0.0.1",1502);}elseif(use_backend == TCP_PI){
ctx =modbus_new_tcp_pi("::1","1502");}else{
ctx =modbus_new_rtu("/dev/ttyUSB1",115200,'N',8,1);}if(ctx == NULL){fprintf(stderr,"Unable to allocate libmodbus context\n");return-1;}modbus_set_debug(ctx, TRUE);modbus_set_error_recovery(ctx,
MODBUS_ERROR_RECOVERY_LINK |
MODBUS_ERROR_RECOVERY_PROTOCOL);if(use_backend == RTU){modbus_set_slave(ctx, SERVER_ID);}modbus_get_response_timeout(ctx,&old_response_to_sec,&old_response_to_usec);if(modbus_connect(ctx)==-1){fprintf(stderr,"Connection failed: %s\n",modbus_strerror(errno));modbus_free(ctx);return-1;}modbus_get_response_timeout(ctx,&new_response_to_sec,&new_response_to_usec);printf("** UNIT TESTING **\n");printf("1/1 No response timeout modification on connect: ");ASSERT_TRUE(old_response_to_sec == new_response_to_sec &&
old_response_to_usec == new_response_to_usec,"");/* Allocate and initialize the memory to store the bits */
nb_points =(UT_BITS_NB > UT_INPUT_BITS_NB)? UT_BITS_NB : UT_INPUT_BITS_NB;
tab_rp_bits =(uint8_t *)malloc(nb_points *sizeof(uint8_t));memset(tab_rp_bits,0, nb_points *sizeof(uint8_t));/* Allocate and initialize the memory to store the registers */
nb_points =(UT_REGISTERS_NB > UT_INPUT_REGISTERS_NB)?
UT_REGISTERS_NB : UT_INPUT_REGISTERS_NB;
tab_rp_registers =(uint16_t *)malloc(nb_points *sizeof(uint16_t));memset(tab_rp_registers,0, nb_points *sizeof(uint16_t));printf("\nTEST WRITE/READ:\n");/** COIL BITS **//* Single */
rc =modbus_write_bit(ctx, UT_BITS_ADDRESS, ON);printf("1/2 modbus_write_bit: ");ASSERT_TRUE(rc ==1,"");
rc =modbus_read_bits(ctx, UT_BITS_ADDRESS,1, tab_rp_bits);printf("2/2 modbus_read_bits: ");ASSERT_TRUE(rc ==1,"FAILED (nb points %d)\n", rc);ASSERT_TRUE(tab_rp_bits[0]== ON,"FAILED (%0X != %0X)\n",
tab_rp_bits[0], ON);/* End single *//* Multiple bits */{
uint8_t tab_value[UT_BITS_NB];modbus_set_bits_from_bytes(tab_value,0, UT_BITS_NB, UT_BITS_TAB);
rc =modbus_write_bits(ctx, UT_BITS_ADDRESS, UT_BITS_NB, tab_value);printf("1/2 modbus_write_bits: ");ASSERT_TRUE(rc == UT_BITS_NB,"");}
rc =modbus_read_bits(ctx, UT_BITS_ADDRESS, UT_BITS_NB, tab_rp_bits);printf("2/2 modbus_read_bits: ");ASSERT_TRUE(rc == UT_BITS_NB,"FAILED (nb points %d)\n", rc);
i =0;
nb_points = UT_BITS_NB;while(nb_points >0){
int nb_bits =(nb_points >8)?8: nb_points;
value =modbus_get_byte_from_bits(tab_rp_bits, i*8, nb_bits);ASSERT_TRUE(value == UT_BITS_TAB[i],"FAILED (%0X != %0X)\n",
value, UT_BITS_TAB[i]);
nb_points -= nb_bits;
i++;}printf("OK\n");/* End of multiple bits *//** DISCRETE INPUTS **/
rc =modbus_read_input_bits(ctx, UT_INPUT_BITS_ADDRESS,
UT_INPUT_BITS_NB, tab_rp_bits);printf("1/1 modbus_read_input_bits: ");ASSERT_TRUE(rc == UT_INPUT_BITS_NB,"FAILED (nb points %d)\n", rc);
i =0;
nb_points = UT_INPUT_BITS_NB;while(nb_points >0){
int nb_bits =(nb_points >8)?8: nb_points;
value =modbus_get_byte_from_bits(tab_rp_bits, i*8, nb_bits);ASSERT_TRUE(value == UT_INPUT_BITS_TAB[i],"FAILED (%0X != %0X)\n",
value, UT_INPUT_BITS_TAB[i]);
nb_points -= nb_bits;
i++;}printf("OK\n");/** HOLDING REGISTERS **//* Single register */
rc =modbus_write_register(ctx, UT_REGISTERS_ADDRESS,0x1234);printf("1/2 modbus_write_register: ");ASSERT_TRUE(rc ==1,"");
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,1, tab_rp_registers);printf("2/2 modbus_read_registers: ");ASSERT_TRUE(rc ==1,"FAILED (nb points %d)\n", rc);ASSERT_TRUE(tab_rp_registers[0]==0x1234,"FAILED (%0X != %0X)\n",
tab_rp_registers[0],0x1234);/* End of single register *//* Many registers */
rc =modbus_write_registers(ctx, UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB, UT_REGISTERS_TAB);printf("1/5 modbus_write_registers: ");ASSERT_TRUE(rc == UT_REGISTERS_NB,"");
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB, tab_rp_registers);printf("2/5 modbus_read_registers: ");ASSERT_TRUE(rc == UT_REGISTERS_NB,"FAILED (nb points %d)\n", rc);for(i=0; i < UT_REGISTERS_NB; i++){ASSERT_TRUE(tab_rp_registers[i]== UT_REGISTERS_TAB[i],"FAILED (%0X != %0X)\n",
tab_rp_registers[i], UT_REGISTERS_TAB[i]);}
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,0, tab_rp_registers);printf("3/5 modbus_read_registers (0): ");ASSERT_TRUE(rc ==-1,"FAILED (nb_points %d)\n", rc);
nb_points =(UT_REGISTERS_NB >
UT_INPUT_REGISTERS_NB)?
UT_REGISTERS_NB : UT_INPUT_REGISTERS_NB;memset(tab_rp_registers,0, nb_points *sizeof(uint16_t));/* Write registers to zero from tab_rp_registers and store read registers
into tab_rp_registers. So the read registers must set to 0, except the
first one because there is an offset of 1 register on write. */
rc =modbus_write_and_read_registers(ctx,
UT_REGISTERS_ADDRESS +1,
UT_REGISTERS_NB -1,
tab_rp_registers,
UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB,
tab_rp_registers);printf("4/5 modbus_write_and_read_registers: ");ASSERT_TRUE(rc == UT_REGISTERS_NB,"FAILED (nb points %d != %d)\n",
rc, UT_REGISTERS_NB);ASSERT_TRUE(tab_rp_registers[0]== UT_REGISTERS_TAB[0],"FAILED (%0X != %0X)\n",
tab_rp_registers[0], UT_REGISTERS_TAB[0]);for(i=1; i < UT_REGISTERS_NB; i++){ASSERT_TRUE(tab_rp_registers[i]==0,"FAILED (%0X != %0X)\n",
tab_rp_registers[i],0);}/* End of many registers *//** INPUT REGISTERS **/
rc =modbus_read_input_registers(ctx, UT_INPUT_REGISTERS_ADDRESS,
UT_INPUT_REGISTERS_NB,
tab_rp_registers);printf("1/1 modbus_read_input_registers: ");ASSERT_TRUE(rc == UT_INPUT_REGISTERS_NB,"FAILED (nb points %d)\n", rc);for(i=0; i < UT_INPUT_REGISTERS_NB; i++){ASSERT_TRUE(tab_rp_registers[i]== UT_INPUT_REGISTERS_TAB[i],"FAILED (%0X != %0X)\n",
tab_rp_registers[i], UT_INPUT_REGISTERS_TAB[i]);}/* MASKS */printf("1/1 Write mask: ");
rc =modbus_write_register(ctx, UT_REGISTERS_ADDRESS,0x12);
rc =modbus_mask_write_register(ctx, UT_REGISTERS_ADDRESS,0xF2,0x25);ASSERT_TRUE(rc !=-1,"FAILED (%x == -1)\n", rc);
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,1, tab_rp_registers);ASSERT_TRUE(tab_rp_registers[0]==0x17,"FAILED (%0X != %0X)\n",
tab_rp_registers[0],0x17);printf("\nTEST FLOATS\n");/** FLOAT **/printf("1/4 Set/get float ABCD: ");modbus_set_float_abcd(UT_REAL, tab_rp_registers);ASSERT_TRUE(equal_dword(tab_rp_registers, UT_IREAL_ABCD),"FAILED Set float ABCD");
real =modbus_get_float_abcd(tab_rp_registers);ASSERT_TRUE(real == UT_REAL,"FAILED (%f != %f)\n", real, UT_REAL);printf("2/4 Set/get float DCBA: ");modbus_set_float_dcba(UT_REAL, tab_rp_registers);ASSERT_TRUE(equal_dword(tab_rp_registers, UT_IREAL_DCBA),"FAILED Set float DCBA");
real =modbus_get_float_dcba(tab_rp_registers);ASSERT_TRUE(real == UT_REAL,"FAILED (%f != %f)\n", real, UT_REAL);printf("3/4 Set/get float BADC: ");modbus_set_float_badc(UT_REAL, tab_rp_registers);ASSERT_TRUE(equal_dword(tab_rp_registers, UT_IREAL_BADC),"FAILED Set float BADC");
real =modbus_get_float_badc(tab_rp_registers);ASSERT_TRUE(real == UT_REAL,"FAILED (%f != %f)\n", real, UT_REAL);printf("4/4 Set/get float CDAB: ");modbus_set_float_cdab(UT_REAL, tab_rp_registers);ASSERT_TRUE(equal_dword(tab_rp_registers, UT_IREAL_CDAB),"FAILED Set float CDAB");
real =modbus_get_float_cdab(tab_rp_registers);ASSERT_TRUE(real == UT_REAL,"FAILED (%f != %f)\n", real, UT_REAL);printf("\nAt this point, error messages doesn't mean the test has failed\n");/** ILLEGAL DATA ADDRESS **/printf("\nTEST ILLEGAL DATA ADDRESS:\n");/* The mapping begins at the defined addresses and ends at address +
* nb_points so these addresses are not valid. */
rc =modbus_read_bits(ctx,0,1, tab_rp_bits);printf("* modbus_read_bits (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_read_bits(ctx, UT_BITS_ADDRESS, UT_BITS_NB +1, tab_rp_bits);printf("* modbus_read_bits (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_read_input_bits(ctx,0,1, tab_rp_bits);printf("* modbus_read_input_bits (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_read_input_bits(ctx, UT_INPUT_BITS_ADDRESS,
UT_INPUT_BITS_NB +1, tab_rp_bits);printf("* modbus_read_input_bits (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_read_registers(ctx,0,1, tab_rp_registers);printf("* modbus_read_registers (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB_MAX +1, tab_rp_registers);printf("* modbus_read_registers (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_read_input_registers(ctx,0,1, tab_rp_registers);printf("* modbus_read_input_registers (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_read_input_registers(ctx, UT_INPUT_REGISTERS_ADDRESS,
UT_INPUT_REGISTERS_NB +1,
tab_rp_registers);printf("* modbus_read_input_registers (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_bit(ctx,0, ON);printf("* modbus_write_bit (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_bit(ctx, UT_BITS_ADDRESS + UT_BITS_NB, ON);printf("* modbus_write_bit (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_bits(ctx,0,1, tab_rp_bits);printf("* modbus_write_coils (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_bits(ctx, UT_BITS_ADDRESS + UT_BITS_NB,
UT_BITS_NB, tab_rp_bits);printf("* modbus_write_coils (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_register(ctx,0, tab_rp_registers[0]);printf("* modbus_write_register (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_register(ctx, UT_REGISTERS_ADDRESS + UT_REGISTERS_NB_MAX,
tab_rp_registers[0]);printf("* modbus_write_register (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_registers(ctx,0,1, tab_rp_registers);printf("* modbus_write_registers (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_registers(ctx, UT_REGISTERS_ADDRESS + UT_REGISTERS_NB_MAX,
UT_REGISTERS_NB, tab_rp_registers);printf("* modbus_write_registers (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_mask_write_register(ctx,0,0xF2,0x25);printf("* modbus_mask_write_registers (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_mask_write_register(ctx, UT_REGISTERS_ADDRESS + UT_REGISTERS_NB_MAX,0xF2,0x25);printf("* modbus_mask_write_registers (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_and_read_registers(ctx,0,1, tab_rp_registers,0,1, tab_rp_registers);printf("* modbus_write_and_read_registers (0): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");
rc =modbus_write_and_read_registers(ctx,
UT_REGISTERS_ADDRESS + UT_REGISTERS_NB_MAX,
UT_REGISTERS_NB, tab_rp_registers,
UT_REGISTERS_ADDRESS + UT_REGISTERS_NB_MAX,
UT_REGISTERS_NB, tab_rp_registers);printf("* modbus_write_and_read_registers (max): ");ASSERT_TRUE(rc ==-1&& errno == EMBXILADD,"");/** TOO MANY DATA **/printf("\nTEST TOO MANY DATA ERROR:\n");
rc =modbus_read_bits(ctx, UT_BITS_ADDRESS,
MODBUS_MAX_READ_BITS +1, tab_rp_bits);printf("* modbus_read_bits: ");ASSERT_TRUE(rc ==-1&& errno == EMBMDATA,"");
rc =modbus_read_input_bits(ctx, UT_INPUT_BITS_ADDRESS,
MODBUS_MAX_READ_BITS +1, tab_rp_bits);printf("* modbus_read_input_bits: ");ASSERT_TRUE(rc ==-1&& errno == EMBMDATA,"");
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,
MODBUS_MAX_READ_REGISTERS +1,
tab_rp_registers);printf("* modbus_read_registers: ");ASSERT_TRUE(rc ==-1&& errno == EMBMDATA,"");
rc =modbus_read_input_registers(ctx, UT_INPUT_REGISTERS_ADDRESS,
MODBUS_MAX_READ_REGISTERS +1,
tab_rp_registers);printf("* modbus_read_input_registers: ");ASSERT_TRUE(rc ==-1&& errno == EMBMDATA,"");
rc =modbus_write_bits(ctx, UT_BITS_ADDRESS,
MODBUS_MAX_WRITE_BITS +1, tab_rp_bits);printf("* modbus_write_bits: ");ASSERT_TRUE(rc ==-1&& errno == EMBMDATA,"");
rc =modbus_write_registers(ctx, UT_REGISTERS_ADDRESS,
MODBUS_MAX_WRITE_REGISTERS +1,
tab_rp_registers);printf("* modbus_write_registers: ");ASSERT_TRUE(rc ==-1&& errno == EMBMDATA,"");/** SLAVE REPLY **/
old_slave =modbus_get_slave(ctx);printf("\nTEST SLAVE REPLY:\n");modbus_set_slave(ctx, INVALID_SERVER_ID);
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB, tab_rp_registers);if(use_backend == RTU){const int RAW_REQ_LENGTH =6;
uint8_t raw_req[]={ INVALID_SERVER_ID,0x03,0x00,0x01,0x01,0x01};/* Too many points */
uint8_t raw_invalid_req[]={ INVALID_SERVER_ID,0x03,0x00,0x01,0xFF,0xFF};const int RAW_RSP_LENGTH =7;
uint8_t raw_rsp[]={ INVALID_SERVER_ID,0x03,0x04,0,0,0,0};
uint8_t rsp[MODBUS_RTU_MAX_ADU_LENGTH];/* No response in RTU mode */printf("1-A/3 No response from slave %d: ", INVALID_SERVER_ID);ASSERT_TRUE(rc ==-1&& errno == ETIMEDOUT,"");/* The slave raises a timeout on a confirmation to ignore because if an
* indication for another slave is received, a confirmation must follow *//* Send a pair of indication/confirmation to the slave with a different
* slave ID to simulate a communication on a RS485 bus. At first, the
* slave will see the indication message then the confirmation, and it must
* ignore both. */modbus_send_raw_request(ctx, raw_req, RAW_REQ_LENGTH *sizeof(uint8_t));modbus_send_raw_request(ctx, raw_rsp, RAW_RSP_LENGTH *sizeof(uint8_t));
rc =modbus_receive_confirmation(ctx, rsp);printf("1-B/3 No response from slave %d on indication/confirmation messages: ",
INVALID_SERVER_ID);ASSERT_TRUE(rc ==-1&& errno == ETIMEDOUT,"");/* Send an INVALID request for another slave */modbus_send_raw_request(ctx, raw_invalid_req, RAW_REQ_LENGTH *sizeof(uint8_t));
rc =modbus_receive_confirmation(ctx, rsp);printf("1-C/3 No response from slave %d with invalid request: ",
INVALID_SERVER_ID);ASSERT_TRUE(rc ==-1&& errno == ETIMEDOUT,"");
rc =modbus_set_slave(ctx, MODBUS_BROADCAST_ADDRESS);ASSERT_TRUE(rc !=-1,"Invalid broadcast address");
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB, tab_rp_registers);printf("2/3 No reply after a broadcast query: ");ASSERT_TRUE(rc ==-1&& errno == ETIMEDOUT,"");}else{/* Response in TCP mode */printf("1/3 Response from slave %d: ", INVALID_SERVER_ID);ASSERT_TRUE(rc == UT_REGISTERS_NB,"");
rc =modbus_set_slave(ctx, MODBUS_BROADCAST_ADDRESS);ASSERT_TRUE(rc !=-1,"Invalid broacast address");
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB, tab_rp_registers);printf("2/3 Reply after a query with unit id == 0: ");ASSERT_TRUE(rc == UT_REGISTERS_NB,"");}/* Restore slave */modbus_set_slave(ctx, old_slave);printf("3/3 Response with an invalid TID or slave: ");
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS_INVALID_TID_OR_SLAVE,1, tab_rp_registers);ASSERT_TRUE(rc ==-1,"");printf("1/2 Report slave ID truncated: \n");/* Set a marker to ensure limit is respected */
tab_rp_bits[NB_REPORT_SLAVE_ID -1]=42;
rc =modbus_report_slave_id(ctx, NB_REPORT_SLAVE_ID -1, tab_rp_bits);/* Return the size required (response size) but respects the defined limit */ASSERT_TRUE(rc == NB_REPORT_SLAVE_ID &&
tab_rp_bits[NB_REPORT_SLAVE_ID -1]==42,"Return is rc %d (%d) and marker is %d (42)",
rc, NB_REPORT_SLAVE_ID, tab_rp_bits[NB_REPORT_SLAVE_ID -1]);printf("2/2 Report slave ID: \n");/* tab_rp_bits is used to store bytes */
rc =modbus_report_slave_id(ctx, NB_REPORT_SLAVE_ID, tab_rp_bits);ASSERT_TRUE(rc == NB_REPORT_SLAVE_ID,"");/* Slave ID is an arbitraty number for libmodbus */ASSERT_TRUE(rc >0,"");/* Run status indicator is ON */ASSERT_TRUE(rc >1&& tab_rp_bits[1]==0xFF,"");/* Print additional data as string */if(rc >2){printf("Additional data: ");for(i=2; i < rc; i++){printf("%c", tab_rp_bits[i]);}printf("\n");}/* Save original timeout */modbus_get_response_timeout(ctx,&old_response_to_sec,&old_response_to_usec);modbus_get_byte_timeout(ctx,&old_byte_to_sec,&old_byte_to_usec);
rc =modbus_set_response_timeout(ctx,0,0);printf("1/6 Invalid response timeout (zero): ");ASSERT_TRUE(rc ==-1&& errno == EINVAL,"");
rc =modbus_set_response_timeout(ctx,0,1000000);printf("2/6 Invalid response timeout (too large us): ");ASSERT_TRUE(rc ==-1&& errno == EINVAL,"");
rc =modbus_set_byte_timeout(ctx,0,1000000);printf("3/6 Invalid byte timeout (too large us): ");ASSERT_TRUE(rc ==-1&& errno == EINVAL,"");modbus_set_response_timeout(ctx,0,1);
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB, tab_rp_registers);printf("4/6 1us response timeout: ");if(rc ==-1&& errno == ETIMEDOUT){printf("OK\n");}else{printf("FAILED (can fail on some platforms)\n");}/* A wait and flush operation is done by the error recovery code of
* libmodbus but after a sleep of current response timeout
* so 0 can be too short!
* /usleep(old_response_to_sec *1000000+ old_response_to_usec);modbus_flush(ctx);/* Trigger a special behaviour on server to wait for 0.5 second before
* replying whereas allowed timeout is 0.2 second */modbus_set_response_timeout(ctx,0,200000);
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS_SLEEP_500_MS,1, tab_rp_registers);printf("5/6 Too short response timeout (0.2s < 0.5s): ");ASSERT_TRUE(rc ==-1&& errno == ETIMEDOUT,"");/* Wait for reply (0.2 + 0.4 > 0.5 s) and flush before continue */usleep(400000);modbus_flush(ctx);modbus_set_response_timeout(ctx,0,600000);
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS_SLEEP_500_MS,1, tab_rp_registers);printf("6/6 Adequate response timeout (0.6s > 0.5s): ");ASSERT_TRUE(rc ==1,"");/* Disable the byte timeout.
The full response must be available in the 600ms interval */modbus_set_byte_timeout(ctx,0,0);
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS_SLEEP_500_MS,1, tab_rp_registers);printf("7/7 Disable byte timeout: ");ASSERT_TRUE(rc ==1,"");/* Restore original response timeout */modbus_set_response_timeout(ctx, old_response_to_sec,
old_response_to_usec);if(use_backend == TCP){/* The test server is only able to test byte timeouts with the TCP
* backend *//* Timeout of 3ms between bytes */modbus_set_byte_timeout(ctx,0,3000);
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS_BYTE_SLEEP_5_MS,1, tab_rp_registers);printf("1/2 Too small byte timeout (3ms < 5ms): ");ASSERT_TRUE(rc ==-1&& errno == ETIMEDOUT,"");/* Wait remaing bytes before flushing */usleep(11*5000);modbus_flush(ctx);/* Timeout of 7ms between bytes */modbus_set_byte_timeout(ctx,0,7000);
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS_BYTE_SLEEP_5_MS,1, tab_rp_registers);printf("2/2 Adapted byte timeout (7ms > 5ms): ");ASSERT_TRUE(rc ==1,"");}/* Restore original byte timeout */modbus_set_byte_timeout(ctx, old_byte_to_sec, old_byte_to_usec);/** BAD RESPONSE **/printf("\nTEST BAD RESPONSE ERROR:\n");/* Allocate only the required space */
tab_rp_registers_bad =(uint16_t *)malloc(
UT_REGISTERS_NB_SPECIAL *sizeof(uint16_t));
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS,
UT_REGISTERS_NB_SPECIAL, tab_rp_registers_bad);printf("* modbus_read_registers: ");ASSERT_TRUE(rc ==-1&& errno == EMBBADDATA,"");free(tab_rp_registers_bad);/** MANUAL EXCEPTION **/printf("\nTEST MANUAL EXCEPTION:\n");
rc =modbus_read_registers(ctx, UT_REGISTERS_ADDRESS_SPECIAL,
UT_REGISTERS_NB, tab_rp_registers);printf("* modbus_read_registers at special address: ");ASSERT_TRUE(rc ==-1&& errno == EMBXSBUSY,"");/** Run a few tests to challenge the server code **/if(test_server(ctx, use_backend)==-1){
goto close;}modbus_close(ctx);modbus_free(ctx);
ctx = NULL;/* Test init functions */printf("\nTEST INVALID INITIALIZATION:\n");
ctx =modbus_new_rtu(NULL,1,'A',0,0);ASSERT_TRUE(ctx == NULL && errno == EINVAL,"");
ctx =modbus_new_rtu("/dev/dummy",0,'A',0,0);ASSERT_TRUE(ctx == NULL && errno == EINVAL,"");
ctx =modbus_new_tcp_pi(NULL, NULL);ASSERT_TRUE(ctx == NULL && errno == EINVAL,"");printf("\nALL TESTS PASS WITH SUCCESS.\n");
success = TRUE;
close:/* Free the memory */free(tab_rp_bits);free(tab_rp_registers);/* Close the connection */modbus_close(ctx);modbus_free(ctx);return(success)?0:-1;}/* Send crafted requests to test server resilience
and ensure proper exceptions are returned. */
int test_server(modbus_t *ctx, int use_backend){
int rc;
int i;/* Read requests */const int READ_RAW_REQ_LEN =6;const int slave =(use_backend == RTU)? SERVER_ID : MODBUS_TCP_SLAVE;
uint8_t read_raw_req[]={
slave,/* function, address, 5 values */
MODBUS_FC_READ_HOLDING_REGISTERS,
UT_REGISTERS_ADDRESS >>8, UT_REGISTERS_ADDRESS &0xFF,0x0,0x05};/* Write and read registers request */const int RW_RAW_REQ_LEN =13;
uint8_t rw_raw_req[]={
slave,/* function, addr to read, nb to read */
MODBUS_FC_WRITE_AND_READ_REGISTERS,/* Read */
UT_REGISTERS_ADDRESS >>8, UT_REGISTERS_ADDRESS &0xFF,(MODBUS_MAX_WR_READ_REGISTERS +1)>>8,(MODBUS_MAX_WR_READ_REGISTERS +1)&0xFF,/* Write */0,0,0,1,/* Write byte count */1*2,/* One data to write... */0x12,0x34};const int WRITE_RAW_REQ_LEN =13;
uint8_t write_raw_req[]={
slave,/* function will be set in the loop */
MODBUS_FC_WRITE_MULTIPLE_REGISTERS,/* Address */
UT_REGISTERS_ADDRESS >>8, UT_REGISTERS_ADDRESS &0xFF,/* 3 values, 6 bytes */0x00,0x03,0x06,/* Dummy data to write */0x02,0x2B,0x00,0x01,0x00,0x64};const int INVALID_FC =0x42;const int INVALID_FC_REQ_LEN =6;
uint8_t invalid_fc_raw_req[]={
slave,0x42,0x00,0x00,0x00,0x00};
int req_length;
uint8_t rsp[MODBUS_TCP_MAX_ADU_LENGTH];
int tab_read_function[]={
MODBUS_FC_READ_COILS,
MODBUS_FC_READ_DISCRETE_INPUTS,
MODBUS_FC_READ_HOLDING_REGISTERS,
MODBUS_FC_READ_INPUT_REGISTERS
};
int tab_read_nb_max[]={
MODBUS_MAX_READ_BITS +1,
MODBUS_MAX_READ_BITS +1,
MODBUS_MAX_READ_REGISTERS +1,
MODBUS_MAX_READ_REGISTERS +1};
int backend_length;
int backend_offset;if(use_backend == RTU){
backend_length =3;
backend_offset =1;}else{
backend_length =7;
backend_offset =7;}printf("\nTEST RAW REQUESTS:\n");
uint32_t old_response_to_sec;
uint32_t old_response_to_usec;/* This requests can generate flushes server side so we need a higher
* response timeout than the server. The server uses the defined response
* timeout to sleep before flushing.
* The old timeouts are restored at the end.
* /modbus_get_response_timeout(ctx,&old_response_to_sec,&old_response_to_usec);modbus_set_response_timeout(ctx,0,600000);
req_length =modbus_send_raw_request(ctx, read_raw_req, READ_RAW_REQ_LEN);printf("* modbus_send_raw_request: ");ASSERT_TRUE(req_length ==(backend_length +5),"FAILED (%d)\n", req_length);printf("* modbus_receive_confirmation: ");
rc =modbus_receive_confirmation(ctx, rsp);ASSERT_TRUE(rc ==(backend_length +12),"FAILED (%d)\n", rc);/* Try to read more values than a response could hold for all data
types. */for(i=0; i<4; i++){
rc =send_crafted_request(ctx, tab_read_function[i],
read_raw_req, READ_RAW_REQ_LEN,
tab_read_nb_max[i],0,
backend_length, backend_offset);if(rc ==-1)
goto close;}
rc =send_crafted_request(ctx, MODBUS_FC_WRITE_AND_READ_REGISTERS,
rw_raw_req, RW_RAW_REQ_LEN,
MODBUS_MAX_WR_READ_REGISTERS +1,0,
backend_length, backend_offset);if(rc ==-1)
goto close;
rc =send_crafted_request(ctx, MODBUS_FC_WRITE_MULTIPLE_REGISTERS,
write_raw_req, WRITE_RAW_REQ_LEN,
MODBUS_MAX_WRITE_REGISTERS +1,6,
backend_length, backend_offset);if(rc ==-1)
goto close;
rc =send_crafted_request(ctx, MODBUS_FC_WRITE_MULTIPLE_COILS,
write_raw_req, WRITE_RAW_REQ_LEN,
MODBUS_MAX_WRITE_BITS +1,6,
backend_length, backend_offset);if(rc ==-1)
goto close;/* Modbus write multiple registers with large number of values but a set a
small number of bytes in requests (not nb * 2 as usual). */
rc =send_crafted_request(ctx, MODBUS_FC_WRITE_MULTIPLE_REGISTERS,
write_raw_req, WRITE_RAW_REQ_LEN,
MODBUS_MAX_WRITE_REGISTERS,6,
backend_length, backend_offset);if(rc ==-1)
goto close;
rc =send_crafted_request(ctx, MODBUS_FC_WRITE_MULTIPLE_COILS,
write_raw_req, WRITE_RAW_REQ_LEN,
MODBUS_MAX_WRITE_BITS,6,
backend_length, backend_offset);if(rc ==-1)
goto close;/* Test invalid function code */modbus_send_raw_request(ctx, invalid_fc_raw_req, INVALID_FC_REQ_LEN *sizeof(uint8_t));
rc =modbus_receive_confirmation(ctx, rsp);printf("Return an exception on unknown function code: ");ASSERT_TRUE(rc ==(backend_length + EXCEPTION_RC)&&
rsp[backend_offset]==(0x80+ INVALID_FC),"")modbus_set_response_timeout(ctx, old_response_to_sec, old_response_to_usec);return0;
close:modbus_set_response_timeout(ctx, old_response_to_sec, old_response_to_usec);return-1;}
int send_crafted_request(modbus_t *ctx, int function,
uint8_t *req, int req_len,
uint16_t max_value, uint16_t bytes,
int backend_length, int backend_offset){
uint8_t rsp[MODBUS_TCP_MAX_ADU_LENGTH];
int j;for(j=0; j<2; j++){
int rc;
req[1]=function;if(j ==0){/* Try to read or write zero values on first iteration */
req[4]=0x00;
req[5]=0x00;if(bytes){/* Write query */
req[6]=0x00;}}else{/* Try to read or write max values + 1 on second iteration */
req[4]=(max_value >>8)&0xFF;
req[5]= max_value &0xFF;if(bytes){/* Write query (nb values * 2 to convert in bytes for registers) */
req[6]= bytes;}}modbus_send_raw_request(ctx, req, req_len *sizeof(uint8_t));if(j ==0){printf("* try function 0x%X: %s 0 values: ",function, bytes ?"write":"read");}else{printf("* try function 0x%X: %s %d values: ",function, bytes ?"write":"read",
max_value);}
rc =modbus_receive_confirmation(ctx, rsp);ASSERT_TRUE(rc ==(backend_length + EXCEPTION_RC)&&
rsp[backend_offset]==(0x80+function)&&
rsp[backend_offset +1]== MODBUS_EXCEPTION_ILLEGAL_DATA_VALUE,"");}return0;
close:return-1;}
After libmodbus is compiled and installed under CentOS7, there will be more executable files such as unit-test-server and unit-test-client in the project root directory, as shown in the following figure:
Use terminal tools such as xshell to open two terminals respectively, and run ./unit-test-server and ./unit-test-client respectively, as shown in the following figure:
References##
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