rt-thread/components/finsh/shell.c

/*
 * Copyright (c) 2006-2025, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2006-04-30     Bernard      the first version for FinSH
 * 2006-05-08     Bernard      change finsh thread stack to 2048
 * 2006-06-03     Bernard      add support for skyeye
 * 2006-09-24     Bernard      remove the code related with hardware
 * 2010-01-18     Bernard      fix down then up key bug.
 * 2010-03-19     Bernard      fix backspace issue and fix device read in shell.
 * 2010-04-01     Bernard      add prompt output when start and remove the empty history
 * 2011-02-23     Bernard      fix variable section end issue of finsh shell
 *                             initialization when use GNU GCC compiler.
 * 2016-11-26     armink       add password authentication
 * 2018-07-02     aozima       add custom prompt support.
 */

#include <rthw.h>
#include <string.h>
#include <stdio.h>

#ifdef RT_USING_FINSH

#include "shell.h"
#include "msh.h"

#ifdef DFS_USING_POSIX
#include <unistd.h>
#include <fcntl.h>
#endif /* DFS_USING_POSIX */

#ifdef RT_USING_POSIX_STDIO
#include <unistd.h>
#include <posix/stdio.h>
#endif /* RT_USING_POSIX_STDIO */

/* finsh thread */
#ifndef RT_USING_HEAP
    static struct rt_thread finsh_thread;
    rt_align(RT_ALIGN_SIZE)
    static char finsh_thread_stack[FINSH_THREAD_STACK_SIZE];
    struct finsh_shell _shell;
#endif

/* finsh symtab */
#ifdef FINSH_USING_SYMTAB
    struct finsh_syscall *_syscall_table_begin  = NULL;
    struct finsh_syscall *_syscall_table_end    = NULL;
#endif

struct finsh_shell *shell;
static char *finsh_prompt_custom = RT_NULL;

#if defined(_MSC_VER) || (defined(__GNUC__) && defined(__x86_64__))
struct finsh_syscall *finsh_syscall_next(struct finsh_syscall *call)
{
    unsigned int *ptr;
    ptr = (unsigned int *)(call + 1);
    while ((*ptr == 0) && ((unsigned int *)ptr < (unsigned int *) _syscall_table_end))
        ptr ++;

    return (struct finsh_syscall *)ptr;
}

#endif /* defined(_MSC_VER) || (defined(__GNUC__) && defined(__x86_64__)) */

#ifdef RT_USING_HEAP
int finsh_set_prompt(const char *prompt)
{
    if (finsh_prompt_custom)
    {
        rt_free(finsh_prompt_custom);
        finsh_prompt_custom = RT_NULL;
    }

    /* strdup */
    if (prompt)
    {
        finsh_prompt_custom = (char *)rt_malloc(strlen(prompt) + 1);
        if (finsh_prompt_custom)
        {
            strcpy(finsh_prompt_custom, prompt);
        }
    }

    return 0;
}
#endif /* RT_USING_HEAP */

#define _MSH_PROMPT "msh "

const char *finsh_get_prompt(void)
{
    static char finsh_prompt[RT_CONSOLEBUF_SIZE + 1] = {0};

    /* check prompt mode */
    if (!shell->prompt_mode)
    {
        finsh_prompt[0] = '\0';
        return finsh_prompt;
    }

    if (finsh_prompt_custom)
    {
        strncpy(finsh_prompt, finsh_prompt_custom, sizeof(finsh_prompt) - 1);
    }
    else
    {
        strcpy(finsh_prompt, _MSH_PROMPT);
    }

#if defined(DFS_USING_POSIX) && defined(DFS_USING_WORKDIR)
    /* get current working directory */
    getcwd(&finsh_prompt[rt_strlen(finsh_prompt)], RT_CONSOLEBUF_SIZE - rt_strlen(finsh_prompt));
#endif

    if (rt_strlen(finsh_prompt) + 2 < RT_CONSOLEBUF_SIZE)
    {
        finsh_prompt[rt_strlen(finsh_prompt)] = '>';
        finsh_prompt[rt_strlen(finsh_prompt) + 1] = '\0';
    }

    return finsh_prompt;
}

/**
 * @ingroup group_finsh
 *
 * This function get the prompt mode of finsh shell.
 *
 * @return prompt the prompt mode, 0 disable prompt mode, other values enable prompt mode.
 */
rt_uint32_t finsh_get_prompt_mode(void)
{
    RT_ASSERT(shell != RT_NULL);
    return shell->prompt_mode;
}

/**
 * @ingroup group_finsh
 *
 * This function set the prompt mode of finsh shell.
 *
 * The parameter 0 disable prompt mode, other values enable prompt mode.
 *
 * @param prompt_mode the prompt mode
 */
void finsh_set_prompt_mode(rt_uint32_t prompt_mode)
{
    RT_ASSERT(shell != RT_NULL);
    shell->prompt_mode = prompt_mode;
}

int finsh_getchar(void)
{
#ifdef RT_USING_DEVICE
    char ch = 0;
#ifdef RT_USING_POSIX_STDIO
    if(read(rt_posix_stdio_get_console(), &ch, 1) > 0)
    {
        return ch;
    }
    else
    {
        return -1; /* EOF */
    }
#else
    rt_device_t device;

    RT_ASSERT(shell != RT_NULL);

    device = shell->device;
    if (device == RT_NULL)
    {
        return -1; /* EOF */
    }

    while (rt_device_read(device, -1, &ch, 1) != 1)
    {
        rt_sem_take(&shell->rx_sem, RT_WAITING_FOREVER);
        if (shell->device != device)
        {
            device = shell->device;
            if (device == RT_NULL)
            {
                return -1;
            }
        }
    }
    return ch;
#endif /* RT_USING_POSIX_STDIO */
#else
    extern signed char rt_hw_console_getchar(void);
    return rt_hw_console_getchar();
#endif /* RT_USING_DEVICE */
}

#if !defined(RT_USING_POSIX_STDIO) && defined(RT_USING_DEVICE)
static rt_err_t finsh_rx_ind(rt_device_t dev, rt_size_t size)
{
    RT_ASSERT(shell != RT_NULL);

    /* release semaphore to let finsh thread rx data */
    rt_sem_release(&shell->rx_sem);

    return RT_EOK;
}

/**
 * @ingroup group_finsh
 *
 * This function sets the input device of finsh shell.
 *
 * @param device_name the name of new input device.
 */
void finsh_set_device(const char *device_name)
{
    rt_device_t dev = RT_NULL;

    RT_ASSERT(shell != RT_NULL);
    dev = rt_device_find(device_name);
    if (dev == RT_NULL)
    {
        rt_kprintf("finsh: can not find device: %s\n", device_name);
        return;
    }

    /* check whether it's a same device */
    if (dev == shell->device) return;
    /* open this device and set the new device in finsh shell */
    if (rt_device_open(dev, RT_DEVICE_OFLAG_RDWR | RT_DEVICE_FLAG_INT_RX | \
                       RT_DEVICE_FLAG_STREAM) == RT_EOK)
    {
        if (shell->device != RT_NULL)
        {
            /* close old finsh device */
            rt_device_close(shell->device);
            rt_device_set_rx_indicate(shell->device, RT_NULL);
        }

        /* clear line buffer before switch to new device */
        rt_memset(shell->line, 0, sizeof(shell->line));
        shell->line_curpos = shell->line_position = 0;

        shell->device = dev;
        rt_device_set_rx_indicate(dev, finsh_rx_ind);
    }
}

/**
 * @ingroup group_finsh
 *
 * This function returns current finsh shell input device.
 *
 * @return the finsh shell input device name is returned.
 */
const char *finsh_get_device()
{
    RT_ASSERT(shell != RT_NULL);
    return shell->device->parent.name;
}
#endif /* !defined(RT_USING_POSIX_STDIO) && defined(RT_USING_DEVICE) */

/**
 * @ingroup group_finsh
 *
 * This function set the echo mode of finsh shell.
 *
 * FINSH_OPTION_ECHO=0x01 is echo mode, other values are none-echo mode.
 *
 * @param echo the echo mode
 */
void finsh_set_echo(rt_uint32_t echo)
{
    RT_ASSERT(shell != RT_NULL);
    shell->echo_mode = (rt_uint8_t)echo;
}

/**
 * @ingroup group_finsh
 *
 * This function gets the echo mode of finsh shell.
 *
 * @return the echo mode
 */
rt_uint32_t finsh_get_echo()
{
    RT_ASSERT(shell != RT_NULL);

    return shell->echo_mode;
}

#ifdef FINSH_USING_AUTH
/**
 * set a new password for finsh
 *
 * @param password new password
 *
 * @return result, RT_EOK on OK, -RT_ERROR on the new password length is less than
 *  FINSH_PASSWORD_MIN or greater than FINSH_PASSWORD_MAX
 */
rt_err_t finsh_set_password(const char *password)
{
    rt_base_t level;
    rt_size_t pw_len = rt_strlen(password);

    if (pw_len < FINSH_PASSWORD_MIN || pw_len > FINSH_PASSWORD_MAX)
        return -RT_ERROR;

    level = rt_hw_interrupt_disable();
    rt_strncpy(shell->password, password, FINSH_PASSWORD_MAX);
    rt_hw_interrupt_enable(level);

    return RT_EOK;
}

/**
 * get the finsh password
 *
 * @return password
 */
const char *finsh_get_password(void)
{
    return shell->password;
}

static void finsh_wait_auth(void)
{
    int ch;
    rt_bool_t input_finish = RT_FALSE;
    char password[FINSH_PASSWORD_MAX] = { 0 };
    rt_size_t cur_pos = 0;
    /* password not set */
    if (rt_strlen(finsh_get_password()) == 0) return;

    while (1)
    {
        rt_kprintf("Password for login: ");
        while (!input_finish)
        {
            while (1)
            {
                /* read one character from device */
                ch = (int)finsh_getchar();
                if (ch < 0)
                {
                    continue;
                }

                if (ch >= ' ' && ch <= '~' && cur_pos < FINSH_PASSWORD_MAX)
                {
                    /* change the printable characters to '*' */
                    rt_kprintf("*");
                    password[cur_pos++] = ch;
                }
                else if (ch == '\b' && cur_pos > 0)
                {
                    /* backspace */
                    cur_pos--;
                    password[cur_pos] = '\0';
                    rt_kprintf("\b \b");
                }
                else if (ch == '\r' || ch == '\n')
                {
                    rt_kprintf("\n");
                    input_finish = RT_TRUE;
                    break;
                }
            }
        }
        if (!rt_strncmp(shell->password, password, FINSH_PASSWORD_MAX)) return;
        else
        {
            /* authentication failed, delay 2S for retry */
            rt_thread_delay(2 * RT_TICK_PER_SECOND);
            rt_kprintf("Sorry, try again.\n");
            cur_pos = 0;
            input_finish = RT_FALSE;
            rt_memset(password, '\0', FINSH_PASSWORD_MAX);
        }
    }
}
#endif /* FINSH_USING_AUTH */

static void shell_auto_complete(char *prefix)
{
    rt_kprintf("\n");
    msh_auto_complete(prefix);

#ifdef FINSH_USING_OPTION_COMPLETION
    msh_opt_auto_complete(prefix);
#endif

    rt_kprintf("%s%s", FINSH_PROMPT, prefix);
}

#ifdef FINSH_USING_HISTORY
static rt_bool_t shell_handle_history(struct finsh_shell *shell)
{
#if defined(_WIN32)
    int i;
    rt_kprintf("\r");

    for (i = 0; i <= 60; i++)
        putchar(' ');
    rt_kprintf("\r");

#else
    rt_kprintf("\033[2K\r");
#endif
    rt_kprintf("%s%s", FINSH_PROMPT, shell->line);
    return RT_FALSE;
}

static void shell_push_history(struct finsh_shell *shell)
{
    if (shell->line_position != 0)
    {
        /* push history */
        if (shell->history_count >= FINSH_HISTORY_LINES)
        {
            /* if current cmd is same as last cmd, don't push */
            if (memcmp(&shell->cmd_history[FINSH_HISTORY_LINES - 1], shell->line, FINSH_CMD_SIZE))
            {
                /* move history */
                int index;
                for (index = 0; index < FINSH_HISTORY_LINES - 1; index ++)
                {
                    rt_memcpy(&shell->cmd_history[index][0],
                           &shell->cmd_history[index + 1][0], FINSH_CMD_SIZE);
                }
                rt_memset(&shell->cmd_history[index][0], 0, FINSH_CMD_SIZE);
                rt_memcpy(&shell->cmd_history[index][0], shell->line, shell->line_position);

                /* it's the maximum history */
                shell->history_count = FINSH_HISTORY_LINES;
            }
        }
        else
        {
            /* if current cmd is same as last cmd, don't push */
            if (shell->history_count == 0 || memcmp(&shell->cmd_history[shell->history_count - 1], shell->line, FINSH_CMD_SIZE))
            {
                shell->current_history = shell->history_count;
                rt_memset(&shell->cmd_history[shell->history_count][0], 0, FINSH_CMD_SIZE);
                rt_memcpy(&shell->cmd_history[shell->history_count][0], shell->line, shell->line_position);

                /* increase count and set current history position */
                shell->history_count ++;
            }
        }
    }
    shell->current_history = shell->history_count;
}
#endif

#if defined(FINSH_USING_WORD_OPERATION)
static int find_prev_word_start(const char *line, int curpos)
{
    if (curpos <= 0) return 0;

    /* Skip whitespace */
    while (--curpos > 0 && (line[curpos] == ' ' || line[curpos] == '\t'));

    /* Find word start */
    while (curpos > 0 && !(line[curpos] == ' ' || line[curpos] == '\t'))
        curpos--;

    return (curpos <= 0) ? 0 : curpos + 1;
}

static int find_next_word_end(const char *line, int curpos, int max)
{
    if (curpos >= max) return max;

    /* Skip to next word */
    while (curpos < max && (line[curpos] == ' ' || line[curpos] == '\t'))
        curpos++;

    /* Find word end */
    while (curpos < max && !(line[curpos] == ' ' || line[curpos] == '\t'))
        curpos++;

    return curpos;
}
#endif /* defined(FINSH_USING_WORD_OPERATION) */

#ifdef RT_USING_HOOK
static void (*_finsh_thread_entry_hook)(void);

/**
 * @ingroup group_finsh
 *
 * @brief This function set a hook function at the entry of finsh thread
 *
 * @param hook the function point to be called
 */
void finsh_thread_entry_sethook(void (*hook)(void))
{
    _finsh_thread_entry_hook = hook;
}
#endif /* RT_USING_HOOK */

static void finsh_thread_entry(void *parameter)
{
    int ch;

    RT_OBJECT_HOOK_CALL(_finsh_thread_entry_hook, ());

    /* normal is echo mode */
#ifndef FINSH_ECHO_DISABLE_DEFAULT
    shell->echo_mode = 1;
#else
    shell->echo_mode = 0;
#endif

#if !defined(RT_USING_POSIX_STDIO) && defined(RT_USING_DEVICE)
    /* set console device as shell device */
    if (shell->device == RT_NULL)
    {
        rt_device_t console = rt_console_get_device();
        if (console)
        {
            finsh_set_device(console->parent.name);
        }
    }
#endif /* !defined(RT_USING_POSIX_STDIO) && defined(RT_USING_DEVICE) */

#ifdef FINSH_USING_AUTH
    /* set the default password when the password isn't setting */
    if (rt_strlen(finsh_get_password()) == 0)
    {
        if (finsh_set_password(FINSH_DEFAULT_PASSWORD) != RT_EOK)
        {
            rt_kprintf("Finsh password set failed.\n");
        }
    }
    /* waiting authenticate success */
    finsh_wait_auth();
#endif

    rt_kprintf(FINSH_PROMPT);

    while (1)
    {
        ch = (int)finsh_getchar();
        if (ch < 0)
        {
            continue;
        }

        /*
         * handle control key
         * up key  : 0x1b 0x5b 0x41
         * down key: 0x1b 0x5b 0x42
         * right key:0x1b 0x5b 0x43
         * left key: 0x1b 0x5b 0x44
         * home    : 0x1b 0x5b 0x31 0x7E
         * insert  : 0x1b 0x5b 0x32 0x7E
         * del     : 0x1b 0x5b 0x33 0x7E
         * end     : 0x1b 0x5b 0x34 0x7E
         */
        if (ch == 0x1b)
        {
            shell->stat = WAIT_SPEC_KEY;
            continue;
        }
        else if (shell->stat == WAIT_SPEC_KEY)
        {
            if (ch == 0x5b || ch == 0x41 || ch == 0x42 || ch == 0x43 || ch == 0x44)
            {
                shell->stat = WAIT_FUNC_KEY;
                continue;
            }

            shell->stat = WAIT_NORMAL;
        }
        else if (shell->stat == WAIT_FUNC_KEY)
        {
            shell->stat = WAIT_NORMAL;

            if (ch == 0x41) /* up key */
            {
#ifdef FINSH_USING_HISTORY
                /* prev history */
                if (shell->current_history > 0)
                    shell->current_history --;
                else
                {
                    shell->current_history = 0;
                    continue;
                }

                /* copy the history command */
                rt_memcpy(shell->line, &shell->cmd_history[shell->current_history][0],
                       FINSH_CMD_SIZE);
                shell->line_curpos = shell->line_position = (rt_uint16_t)strlen(shell->line);
                shell_handle_history(shell);
#endif
                continue;
            }
            else if (ch == 0x42) /* down key */
            {
#ifdef FINSH_USING_HISTORY
                /* next history */
                if (shell->current_history < shell->history_count - 1)
                    shell->current_history ++;
                else
                {
                    /* set to the end of history */
                    if (shell->history_count != 0)
                        shell->current_history = shell->history_count - 1;
                    else
                        continue;
                }

                rt_memcpy(shell->line, &shell->cmd_history[shell->current_history][0],
                       FINSH_CMD_SIZE);
                shell->line_curpos = shell->line_position = (rt_uint16_t)strlen(shell->line);
                shell_handle_history(shell);
#endif
                continue;
            }
            else if (ch == 0x44) /* left key */
            {
                if (shell->line_curpos)
                {
                    rt_kprintf("\b");
                    shell->line_curpos --;
                }

                continue;
            }
            else if (ch == 0x43) /* right key */
            {
                if (shell->line_curpos < shell->line_position)
                {
                    rt_kprintf("%c", shell->line[shell->line_curpos]);
                    shell->line_curpos ++;
                }

                continue;
            }
#if defined(FINSH_USING_WORD_OPERATION)
            /* Add Ctrl+Left/Right handling */
            else if (ch == '1')
            {
                /* Read modifier sequence [1;5D/C] */
                int next_ch = finsh_getchar();
                if (next_ch == ';')
                {
                    next_ch = finsh_getchar();
                    if (next_ch == '5')
                    {
                        next_ch = finsh_getchar();
                        if (next_ch == 'D') /* Ctrl+Left */
                        {
                            int new_pos = find_prev_word_start(shell->line, shell->line_curpos);
                            if (new_pos != shell->line_curpos)
                            {
                                rt_kprintf("\033[%dD", shell->line_curpos - new_pos);
                                shell->line_curpos = new_pos;
                            }
                            continue;
                        }
                        else if (next_ch == 'C') /* Ctrl+Right */
                        {
                            int new_pos = find_next_word_end(shell->line, shell->line_curpos, shell->line_position);
                            if (new_pos != shell->line_curpos)
                            {
                                rt_kprintf("\033[%dC", new_pos - shell->line_curpos);
                                shell->line_curpos = new_pos;
                            }
                            continue;
                        }
                    }
                }
            }
#endif /*defined(FINSH_USING_WORD_OPERATION) */
#if defined(FINSH_USING_FUNC_EXT)
            else if (ch >= 0x31 && ch <= 0x34) /* home(0x31), insert(0x32), del(0x33), end(0x34) */
            {
                shell->stat                           = WAIT_EXT_KEY;
                shell->line[shell->line_position + 1] = ch; /* store the key code */
                continue;
            }

        }
        else if (shell->stat == WAIT_EXT_KEY)
        {
            shell->stat = WAIT_NORMAL;

            if (ch == 0x7E) /* extended key terminator */
            {
                rt_uint8_t key_code = shell->line[shell->line_position + 1];

                if (key_code == 0x31) /* home key */
                {
                    /* move cursor to beginning of line */
                    while (shell->line_curpos > 0)
                    {
                        rt_kprintf("\b");
                        shell->line_curpos--;
                    }
                }
                else if (key_code == 0x32) /* insert key */
                {
                    /* toggle insert mode */
                    shell->overwrite_mode = !shell->overwrite_mode;
                }
                else if (key_code == 0x33) /* del key */
                {
                    /* delete character at current cursor position */
                    if (shell->line_curpos < shell->line_position)
                    {
                        int i;
                        shell->line_position--;
                        rt_memmove(&shell->line[shell->line_curpos],
                                   &shell->line[shell->line_curpos + 1],
                                   shell->line_position - shell->line_curpos);

                        shell->line[shell->line_position] = 0;

                        rt_kprintf("%s ", &shell->line[shell->line_curpos]);

                        /* move cursor back to original position */
                        for (i = shell->line_curpos; i <= shell->line_position; i++)
                            rt_kprintf("\b");
                    }
                }
                else if (key_code == 0x34) /* end key */
                {
                    /* move cursor to end of line */
                    while (shell->line_curpos < shell->line_position)
                    {
                        rt_kprintf("%c", shell->line[shell->line_curpos]);
                        shell->line_curpos++;
                    }
                }
                continue;
            }
#endif /*defined(FINSH_USING_FUNC_EXT) */
        }

        /* received null or error */
        if (ch == '\0' || ch == 0xFF) continue;
        /* handle tab key */
        else if (ch == '\t')
        {
            int i;
            /* move the cursor to the beginning of line */
            for (i = 0; i < shell->line_curpos; i++)
                rt_kprintf("\b");

            /* auto complete */
            shell_auto_complete(&shell->line[0]);
            /* re-calculate position */
            shell->line_curpos = shell->line_position = (rt_uint16_t)strlen(shell->line);

            continue;
        }
        /* handle backspace key */
        else if (ch == 0x7f || ch == 0x08)
        {
            /* note that shell->line_curpos >= 0 */
            if (shell->line_curpos == 0)
                continue;

            shell->line_position--;
            shell->line_curpos--;

            if (shell->line_position > shell->line_curpos)
            {
                int i;

                rt_memmove(&shell->line[shell->line_curpos],
                           &shell->line[shell->line_curpos + 1],
                           shell->line_position - shell->line_curpos);
                shell->line[shell->line_position] = 0;

                rt_kprintf("\b%s  \b", &shell->line[shell->line_curpos]);

                /* move the cursor to the origin position */
                for (i = shell->line_curpos; i <= shell->line_position; i++)
                    rt_kprintf("\b");
            }
            else
            {
                rt_kprintf("\b \b");
                shell->line[shell->line_position] = 0;
            }

            continue;
        }
#if defined(FINSH_USING_WORD_OPERATION)
        /* Add Ctrl+Backspace handling */
        else if (ch == 0x17) /* Ctrl+Backspace (typically ^W) */
        {
            if (shell->line_curpos == 0) continue;

            int start = find_prev_word_start(shell->line, shell->line_curpos);
            int del_count = shell->line_curpos - start;
            int new_len = shell->line_position - del_count;

            /* Delete characters and properly add RT_NULL termination */
            rt_memmove(&shell->line[start],
                       &shell->line[start + del_count],
                       new_len - start + 1);

            /* Clear residual data */
            rt_memset(&shell->line[new_len], 0, shell->line_position - new_len);

            /* Update positions */
            shell->line_position = new_len;
            shell->line_curpos = start;

            /* Redraw the affected line section */
            rt_kprintf("\033[%dD", del_count);
            /* Rewrite the remaining content */
            rt_kprintf("%.*s", shell->line_position - start, &shell->line[start]);
            /* Clear trailing artifacts */
            rt_kprintf("\033[K");
            if (shell->line_position > start)
            {
                /* Reset cursor */
                rt_kprintf("\033[%dD", shell->line_position - start);
            }

            continue;
        }
#endif /*defined(FINSH_USING_WORD_OPERATION) */
        /* handle end of line, break */
        if (ch == '\r' || ch == '\n')
        {
#ifdef FINSH_USING_HISTORY
            shell_push_history(shell);
#endif
            if (shell->echo_mode)
                rt_kprintf("\n");
            msh_exec(shell->line, shell->line_position);

            rt_kprintf(FINSH_PROMPT);
            rt_memset(shell->line, 0, sizeof(shell->line));
            shell->line_curpos = shell->line_position = 0;
            continue;
        }

        /* it's a large line, discard it */
        if (shell->line_position >= FINSH_CMD_SIZE)
            shell->line_position = 0;

        /* normal character */
        if (shell->line_curpos < shell->line_position)
        {
            int i;
#if defined(FINSH_USING_FUNC_EXT)
            if (shell->overwrite_mode) /* overwrite mode */
            {
                /* directly overwrite the character */
                shell->line[shell->line_curpos] = ch;
                if (shell->echo_mode)
                    rt_kprintf("%c", ch);
                shell->line_curpos++;
            }
            else /* insert mode */
#endif /*defined(FINSH_USING_FUNC_EXT)*/
            {
                shell->line_position++;
                /* move existing characters to the right */
                rt_memmove(&shell->line[shell->line_curpos + 1],
                           &shell->line[shell->line_curpos],
                           shell->line_position - shell->line_curpos);
                shell->line[shell->line_curpos] = ch;

                if (shell->echo_mode)
                {
                    rt_kprintf("%s", &shell->line[shell->line_curpos]);
                    /* move cursor back to correct position */
                    for (i = shell->line_curpos + 1; i < shell->line_position; i++)
                        rt_kprintf("\b");
                }
                shell->line_curpos++;
            }
        }
        else
        {
            /* append character at end of line */
            shell->line[shell->line_position] = ch;
            if (shell->echo_mode)
                rt_kprintf("%c", ch);
            shell->line_position++;
            shell->line_curpos++;
        }

        ch = 0;
        if (shell->line_position >= FINSH_CMD_SIZE)
        {
            /* clear command line */
            shell->line_position = 0;
            shell->line_curpos = 0;
        }
    } /* end of device read */
}

static void finsh_system_function_init(const void *begin, const void *end)
{
    _syscall_table_begin = (struct finsh_syscall *) begin;
    _syscall_table_end = (struct finsh_syscall *) end;
}

#if defined(__ICCARM__) || defined(__ICCRX__)               /* for IAR compiler */
#ifdef FINSH_USING_SYMTAB
    #pragma section="FSymTab"
#endif
#elif defined(__ADSPBLACKFIN__) /* for VisaulDSP++ Compiler*/
#ifdef FINSH_USING_SYMTAB
    extern "asm" int __fsymtab_start;
    extern "asm" int __fsymtab_end;
#endif
#elif defined(_MSC_VER)
#pragma section("FSymTab$a", read)
const char __fsym_begin_name[] = "__start";
const char __fsym_begin_desc[] = "begin of finsh";
__declspec(allocate("FSymTab$a")) const struct finsh_syscall __fsym_begin =
{
    __fsym_begin_name,
    __fsym_begin_desc,
    NULL
};

#pragma section("FSymTab$z", read)
const char __fsym_end_name[] = "__end";
const char __fsym_end_desc[] = "end of finsh";
__declspec(allocate("FSymTab$z")) const struct finsh_syscall __fsym_end =
{
    __fsym_end_name,
    __fsym_end_desc,
    NULL
};
#endif

/*
 * @ingroup group_finsh
 *
 * This function will initialize finsh shell
 */
int finsh_system_init(void)
{
    rt_err_t result = RT_EOK;
    rt_thread_t tid;

#ifdef FINSH_USING_SYMTAB
#ifdef __ARMCC_VERSION  /* ARM C Compiler */
    extern const int FSymTab$$Base;
    extern const int FSymTab$$Limit;
    finsh_system_function_init(&FSymTab$$Base, &FSymTab$$Limit);
#elif defined (__ICCARM__) || defined(__ICCRX__)      /* for IAR Compiler */
    finsh_system_function_init(__section_begin("FSymTab"),
                               __section_end("FSymTab"));
#elif defined (__GNUC__) || defined(__TI_COMPILER_VERSION__) || defined(__TASKING__)
    /* GNU GCC Compiler and TI CCS */
    extern const int __fsymtab_start;
    extern const int __fsymtab_end;
    finsh_system_function_init(&__fsymtab_start, &__fsymtab_end);
#elif defined(__ADSPBLACKFIN__) /* for VisualDSP++ Compiler */
    finsh_system_function_init(&__fsymtab_start, &__fsymtab_end);
#elif defined(_MSC_VER)
    unsigned int *ptr_begin, *ptr_end;

    if (shell)
    {
        rt_kprintf("finsh shell already init.\n");
        return RT_EOK;
    }

    ptr_begin = (unsigned int *)&__fsym_begin;
    ptr_begin += (sizeof(struct finsh_syscall) / sizeof(unsigned int));
    while (*ptr_begin == 0) ptr_begin ++;

    ptr_end = (unsigned int *) &__fsym_end;
    ptr_end --;
    while (*ptr_end == 0) ptr_end --;

    finsh_system_function_init(ptr_begin, ptr_end);
#endif
#endif

#ifdef RT_USING_HEAP
    /* create or set shell structure */
    shell = (struct finsh_shell *)rt_calloc(1, sizeof(struct finsh_shell));
    if (shell == RT_NULL)
    {
        rt_kprintf("no memory for shell\n");
        return -1;
    }
    tid = rt_thread_create(FINSH_THREAD_NAME,
                           finsh_thread_entry, RT_NULL,
                           FINSH_THREAD_STACK_SIZE, FINSH_THREAD_PRIORITY, 10);
#else
    shell = &_shell;
    tid = &finsh_thread;
    result = rt_thread_init(&finsh_thread,
                            FINSH_THREAD_NAME,
                            finsh_thread_entry, RT_NULL,
                            &finsh_thread_stack[0], sizeof(finsh_thread_stack),
                            FINSH_THREAD_PRIORITY, 10);
#endif /* RT_USING_HEAP */

    rt_sem_init(&(shell->rx_sem), "shrx", 0, 0);
    finsh_set_prompt_mode(1);

    if (tid != NULL && result == RT_EOK)
        rt_thread_startup(tid);
    return 0;
}
INIT_APP_EXPORT(finsh_system_init);

#endif /* RT_USING_FINSH */