RIOT/sys/shell/shell.c

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Copyright 2009, Freie Universitaet Berlin (FUB). All rights reserved.

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/**
 * @ingroup	shell
 * @{
 */

/**
 * @file
 * @brief 		Implementation of a very simple command interpreter.
 *              For each command (i.e. "echo"), a handler can be specified.
 *              If the first word of a user-entered command line matches the
 *              name of a handler, the handler will be called with the whole
 *              command line as parameter.
 *
 * @author      Freie Universität Berlin, Computer Systems & Telematics
 * @author		Kaspar Schleiser <kaspar@schleiser.de>
 */

#include <sys/unistd.h>
#include <string.h>
#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
#include <shell.h>

static void(*find_handler(const shell_command_t *command_list, char *command))(char*) {
    const shell_command_t *entry = command_list;

    while(entry->name != NULL) {
        if ( strcmp(entry->name, command) == 0) {
            return entry->handler;
        } else {
            entry++;
        }
    }
    return NULL;
}

static void print_help(const shell_command_t *command_list) {
    const shell_command_t *entry = command_list;

    printf("%-20s %s\n", "Command", "Description");

    while(entry->name != NULL) {
        printf("%-20s %s\n", entry->name, entry->desc);
        entry++;
    }
}

static void handle_input_line(shell_t *shell, char* line) {
    char* saveptr;
    char* linedup = strdup(line);
    char* command = strtok_r(linedup, " ", &saveptr);

    void (*handler)(char*) = NULL;
    
    if (command) {
        handler = find_handler(shell->command_list, command);
        if (handler != NULL) {
            handler(line);
        } else {
            if ( strcmp("help", command) == 0) {
                print_help(shell->command_list);
            } else {
                puts("shell: command not found.");
            }
        }
    }

    free(linedup);
}

int readline(shell_t *shell, char* buf, int size) {
    char *line_buf_ptr = buf;
    int c;

    while (1) {
        if ( (line_buf_ptr - buf) >= size-1) {
            return -1;
        }

        c = shell->readchar();
        shell->put_char(c);

        if (c == 13) continue;

        if (c == 10) {
            *line_buf_ptr = '\0';
            return 0;
        } else {
            *line_buf_ptr++ = c;
        }
    }
}

void shell_run(shell_t *shell) {
    char line_buf[255];

    while(1) {
        shell->put_char('> ');
        int res = readline(shell, line_buf, sizeof(line_buf));
        if (! res ) {
            char* line_copy = strdup(line_buf);
            handle_input_line(shell, line_copy);
            free(line_copy);
        }
    }
}

void shell_init(shell_t *shell, const shell_command_t *shell_commands, int(*readchar)(void), void(*put_char)(int)) {
    shell->command_list = shell_commands;
    shell->readchar = readchar;
    shell->put_char = put_char;
}

/** @} */