CentOS7下编译安装libmodbus库_centos7 qt libmodbus

下载libdmodbus源代码

libmodbus官网下载页面如下图所示：

可以从如下链接下载libmodbus源代码

• libmodbus-3.1.6.tar.gz
• libmodbus-3.0.8.tar.gz
  当然也可以直接从github上面克隆源代码到本地

git clone https://github.com/stephane/libmodbus.git
1

下载后的源代码目录如下图所示：

编译安装lidmodbus

关于如何安装libmodbus在上面已经说得很清楚了：

在libmodbus根目录下直接运行下面的命令编译、安装libmodbus库

./autogen.sh 
./configure
make
make install
1
2
3
4

相关编译安装过程如下图所示：


可以看到默认情况下libmodbus的头文件被放到/usr/local/include目录下，动态库文件放到/usr/local/lib目录下。

至此，CentOS7下的libmodbus编译和安装就完成了。

测试

关于libmodbus的一些测试，Github上面也描述得比较清楚了：

libmodbus官网提供的一些测试示例如下图所示：

• libmodbus/tests/unit-test-server.c

/*
 * Copyright © 2008-2014 Stéphane Raimbault <stephane.raimbault@gmail.com>
 *
 * 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;
        } else if (strcmp(argv[1], "tcppi") == 0) {
   
            use_backend = TCP_PI;
        } else if (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);
    } else if (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);
    } else if (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);
            } else if (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;
            } else if (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;
            } else if (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);
            } else if (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);

    return 0;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237

• libmodbus/tests/unit-test-client.c

/*
 * Copyright © 2008-2014 Stéphane Raimbault <stephane.raimbault@gmail.com>
 *
 * 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 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31