1 /* Select Example
2
3 This example code is in the Public Domain (or CC0 licensed, at your option.)
4
5 Unless required by applicable law or agreed to in writing, this
6 software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
7 CONDITIONS OF ANY KIND, either express or implied.
8 */
9 #include <stdio.h>
10 #include <sys/fcntl.h>
11 #include <sys/errno.h>
12 #include <sys/unistd.h>
13 #include <sys/param.h>
14 #include <sys/select.h>
15 #include "freertos/FreeRTOS.h"
16 #include "freertos/task.h"
17 #include "esp_log.h"
18 #include "esp_vfs.h"
19 #include "esp_vfs_dev.h"
20 #include "driver/uart.h"
21 #include "esp_netif.h"
22 #include "lwip/sockets.h"
23 #include "lwip/netdb.h"
24
25 static const char* TAG = "uart_select_example";
26
27 static int uart_fd = -1;
28 static int socket_fd = -1;
29
socket_deinit(void)30 static void socket_deinit(void)
31 {
32 close(socket_fd);
33 socket_fd = -1;
34 }
35
socket_init(void)36 static void socket_init(void)
37 {
38 const struct addrinfo hints = {
39 .ai_family = AF_INET,
40 .ai_socktype = SOCK_DGRAM,
41 };
42 struct addrinfo *res;
43 int err;
44 struct sockaddr_in saddr = { 0 };
45
46 ESP_ERROR_CHECK(esp_netif_init());
47
48 err = getaddrinfo("localhost", "80", &hints, &res);
49
50 if (err != 0 || res == NULL) {
51 ESP_LOGE(TAG, "DNS lookup failed: %d", errno);
52 return;
53 }
54
55 socket_fd = socket(res->ai_family, res->ai_socktype, 0);
56
57 if (socket_fd < 0) {
58 ESP_LOGE(TAG, "Failed to allocate socket.");
59 freeaddrinfo(res);
60 return;
61 }
62
63 saddr.sin_family = PF_INET;
64 saddr.sin_port = htons(80);
65 saddr.sin_addr.s_addr = htonl(INADDR_ANY);
66 err = bind(socket_fd, (struct sockaddr *) &saddr, sizeof(struct sockaddr_in));
67 if (err < 0) {
68 ESP_LOGE(TAG, "Failed to bind socket");
69 freeaddrinfo(res);
70 socket_deinit();
71 return;
72 }
73
74 if (connect(socket_fd, res->ai_addr, res->ai_addrlen) != 0) {
75 ESP_LOGE(TAG, "Socket connection failed: %d", errno);
76 freeaddrinfo(res);
77 socket_deinit();
78 return;
79 }
80
81 freeaddrinfo(res);
82 }
83
uart1_deinit(void)84 static void uart1_deinit(void)
85 {
86 close(uart_fd);
87 uart_fd = -1;
88 uart_driver_delete(UART_NUM_1);
89 }
90
uart1_init(void)91 static void uart1_init(void)
92 {
93 uart_config_t uart_config = {
94 .baud_rate = 115200,
95 .data_bits = UART_DATA_8_BITS,
96 .parity = UART_PARITY_DISABLE,
97 .stop_bits = UART_STOP_BITS_1,
98 .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
99 .source_clk = UART_SCLK_APB,
100 };
101 uart_driver_install(UART_NUM_1, 256, 0, 0, NULL, 0);
102 uart_param_config(UART_NUM_1, &uart_config);
103 uart_set_loop_back(UART_NUM_1, true);
104
105 if ((uart_fd = open("/dev/uart/1", O_RDWR | O_NONBLOCK)) == -1) {
106 ESP_LOGE(TAG, "Cannot open UART1");
107 uart1_deinit();
108 }
109
110 esp_vfs_dev_uart_use_driver(1);
111 }
112
uart1_write_task(void * param)113 static void uart1_write_task(void *param)
114 {
115 char buf[20];
116
117 uart1_init();
118
119 for (uint8_t i = 1;; ++i) {
120 vTaskDelay(4000 / portTICK_PERIOD_MS);
121
122 snprintf(buf, sizeof(buf), "UART message U%d", i);
123 int write_bytes = write(uart_fd, buf, strlen(buf));
124 if (write_bytes < 0) {
125 ESP_LOGE(TAG, "UART1 write error");
126 } else {
127 ESP_LOGI(TAG, "%d bytes were sent to UART1: %s", write_bytes, buf);
128 }
129 }
130
131 uart1_deinit();
132 vTaskDelete(NULL);
133 }
134
socket_write_task(void * param)135 static void socket_write_task(void *param)
136 {
137 char buf[20];
138
139 socket_init();
140
141 for (uint8_t i = 1;; ++i) {
142 vTaskDelay(3000 / portTICK_PERIOD_MS);
143
144 snprintf(buf, sizeof(buf), "Socket message S%d", i);
145 int write_bytes = write(socket_fd, buf, strlen(buf));
146 if (write_bytes < 0) {
147 ESP_LOGE(TAG, "Socket write error");
148 } else {
149 ESP_LOGI(TAG, "%d bytes were written to socket: %s", write_bytes, buf);
150 }
151 }
152
153 socket_deinit();
154 vTaskDelete(NULL);
155 }
156
check_and_print(int fd,const fd_set * rfds,const char * src_msg)157 static void check_and_print(int fd, const fd_set *rfds, const char *src_msg)
158 {
159 char buf[100];
160 int read_bytes;
161
162 if (FD_ISSET(fd, rfds)) {
163 if ((read_bytes = read(fd, buf, sizeof(buf)-1)) > 0) {
164 buf[read_bytes] = '\0';
165 ESP_LOGI(TAG, "%d bytes were received through %s: %s", read_bytes, src_msg, buf);
166 } else {
167 ESP_LOGE(TAG, "%s read error", src_msg);
168 }
169 }
170 }
171
select_task(void * param)172 static void select_task(void *param)
173 {
174 while (1) {
175 int s;
176 fd_set rfds;
177 struct timeval tv = {
178 .tv_sec = 1,
179 .tv_usec = 0,
180 };
181
182 FD_ZERO(&rfds);
183 FD_SET(uart_fd, &rfds);
184 FD_SET(socket_fd, &rfds);
185
186 s = select(MAX(uart_fd, socket_fd) + 1, &rfds, NULL, NULL, &tv);
187
188 if (s < 0) {
189 ESP_LOGE(TAG, "Select failed: errno %d", errno);
190 } else if (s == 0) {
191 ESP_LOGI(TAG, "Timeout has been reached and nothing has been received");
192 } else {
193 check_and_print(socket_fd, &rfds, "socket");
194 check_and_print(uart_fd, &rfds, "UART1");
195 }
196 }
197
198 vTaskDelete(NULL);
199 }
200
app_main(void)201 void app_main(void)
202 {
203 xTaskCreate(uart1_write_task, "uart1_write_task", 4*1024, NULL, 5, NULL);
204 xTaskCreate(socket_write_task, "socket_write_task", 4*1024, NULL, 5, NULL);
205 vTaskDelay(1000 / portTICK_PERIOD_MS);
206 xTaskCreate(select_task, "select_task", 4*1024, NULL, 5, NULL);
207 }
208
