Simple Shell

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13

#include "shell.h"

#define CMD_LEN 128

int main() {
    shell_init();

    while (1) {
        char cmd[CMD_LEN];
        shell_input(cmd);
        shell_controller(cmd);
    }
}

 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

void shell_input(char* cmd) {
    uart_printf("\r# ");

    int idx = 0, end = 0, i;
    cmd[0] = '\0';
    char c;
    while ((c = uart_read()) != '\n') {
        // Decode CSI key sequences
        if (c == 27) {
            enum ANSI_ESC key = decode_ansi_escape();
            switch (key) {
                case CursorForward:
                    if (idx < end) idx++;
                    break;

                case CursorBackward:
                    if (idx > 0) idx--;
                    break;

                case Delete:
                    // left shift command
                    for (i = idx; i < end; i++) {
                        cmd[i] = cmd[i + 1];
                    }
                    cmd[--end] = '\0';
                    break;

                case Unknown:
                    uart_flush();
                    break;
            }
        }
        // CTRL-C
        else if (c == 3) {
            cmd[0] = '\0';
            break;
        }
        // Backspace
        else if (c == 8 || c == 127) {
            if (idx > 0) {
                idx--;
                // left shift command
                for (i = idx; i < end; i++) {
                    cmd[i] = cmd[i + 1];
                }
                cmd[--end] = '\0';
            }
        }
        else {
            // right shift command
            if (idx < end) {
                for (i = end; i > idx; i--) {
                    cmd[i] = cmd[i - 1];
                }
            }
            cmd[idx++] = c;
            cmd[++end] = '\0';
        }
        uart_printf("\r# %s \r\e[%dC", cmd, idx + 2);
    }

    uart_printf("\n");
}

 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

void shell_controller(char* cmd) {
    if (!strcmp(cmd, "")) {
        return;
    }
    else if (!strcmp(cmd, "help")) {
        uart_printf("help: print all available commands\n");
        uart_printf("hello: print Hello World!\n");
        uart_printf("timestamp: get current timestamp\n");
        uart_printf("reboot: reboot pi\n");
    }
    else if (!strcmp(cmd, "hello")) {
        uart_printf("Hello World!\n");
    }
    else if (!strcmp(cmd, "timestamp")) {
        uart_printf("%f\n", get_timestamp());
    }
    else if (!strcmp(cmd, "reboot")) {
        uart_printf("Rebooting...");
        reset();
        while (1); // hang until reboot
    }
    else {
        uart_printf("shell: command not found: %s\n", cmd);
    }
}