webshh 的 c 语言实现

WebSSH 的 C 语言实现通常基于 libssh 库，该库提供了在 C 语言中实现 SSH 协议的功能。以下是一个简单的 C 语言实现 WebSSH 的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <libssh/libssh.h>

int main()
{
    ssh_session my_ssh_session;
    int rc;

    my_ssh_session = ssh_new();

    if (my_ssh_session == NULL)
    {
        exit(-1);
    }

    ssh_options_set(my_ssh_session, SSH_OPTIONS_HOST, "example.com");
    ssh_options_set(my_ssh_session, SSH_OPTIONS_PORT, 22);
    ssh_options_set(my_ssh_session, SSH_OPTIONS_USER, "username");

    rc = ssh_connect(my_ssh_session);

    if (rc != SSH_OK)
    {
        ssh_disconnect(my_ssh_session);
        ssh_free(my_ssh_session);
        exit(-1);
    }

    rc = ssh_userauth_password(my_ssh_session, NULL, "password");

    if (rc != SSH_AUTH_SUCCESS)
    {
        ssh_disconnect(my_ssh_session);
        ssh_free(my_ssh_session);
        exit(-1);
    }

    ssh_channel my_ssh_channel;
    my_ssh_channel = ssh_channel_new(my_ssh_session);

    if (my_ssh_channel == NULL)
    {
        ssh_disconnect(my_ssh_session);
        ssh_free(my_ssh_session);
        exit(-1);
    }

    rc = ssh_channel_open_session(my_ssh_channel);

    if (rc != SSH_OK)
    {
        ssh_channel_free(my_ssh_channel);
        ssh_disconnect(my_ssh_session);
        ssh_free(my_ssh_session);
        exit(-1);
    }

    rc = ssh_channel_request_pty(my_ssh_channel);

    if (rc != SSH_OK)
    {
        ssh_channel_close(my_ssh_channel);
        ssh_channel_free(my_ssh_channel);
        ssh_disconnect(my_ssh_session);
        ssh_free(my_ssh_session);
        exit(-1);
    }

    rc = ssh_channel_change_pty_size(my_ssh_channel, 80, 24);

    if (rc != SSH_OK)
    {
        ssh_channel_close(my_ssh_channel);
        ssh_channel_free(my_ssh_channel);
        ssh_disconnect(my_ssh_session);
        ssh_free(my_ssh_session);
        exit(-1);
    }

    rc = ssh_channel_request_shell(my_ssh_channel);

    if (rc != SSH_OK)
    {
        ssh_channel_close(my_ssh_channel);
        ssh_channel_free(my_ssh_channel);
        ssh_disconnect(my_ssh_session);
        ssh_free(my_ssh_session);
        exit(-1);
    }

    char buffer[1024];

    while (ssh_channel_is_open(my_ssh_channel) && !ssh_channel_is_eof(my_ssh_channel))
    {
        int nbytes = ssh_channel_read(my_ssh_channel, buffer, sizeof(buffer), 0);

        if (nbytes < 0)
        {
            ssh_channel_close(my_ssh_channel);
            ssh_channel_free(my_ssh_channel);
            ssh_disconnect(my_ssh_session);
            ssh_free(my_ssh_session);
            exit(-1);
        }

        printf("%.*s", nbytes, buffer);

        if (ssh_channel_is_closed(my_ssh_channel))
        {
            break;
        }

        fd_set readfds;
        FD_ZERO(&readfds);
        FD_SET(0, &readfds);
        FD_SET(ssh_get_fd(my_ssh_session), &readfds);

        rc = select(ssh_get_fd(my_ssh_session) + 1, &readfds, NULL, NULL, NULL);

        if (rc < 0)
        {
            ssh_channel_close(my_ssh_channel);
            ssh_channel_free(my_ssh_channel);
            ssh_disconnect(my_ssh_session);
            ssh_free(my_ssh_session);
            exit(-1);
        }

        if (FD_ISSET(0, &readfds))
        {
            nbytes = read(0, buffer, sizeof(buffer));

            if (nbytes > 0)
            {
                rc = ssh_channel_write(my_ssh_channel, buffer, nbytes);

                if (rc < 0)
                {
                    ssh_channel_close(my_ssh_channel);
                    ssh_channel_free(my_ssh_channel);
                    ssh_disconnect(my_ssh_session);
                    ssh_free(my_ssh_session);
                    exit(-1);
                }
            }
        }

        if (FD_ISSET(ssh_get_fd(my_ssh_session), &readfds))
        {
            nbytes = ssh_channel_read(my_ssh_channel, buffer, sizeof(buffer), 0);

            if (nbytes > 0)
            {
                printf("%.*s", nbytes, buffer);
            }
        }
    }

    ssh_channel_close(my_ssh_channel);
    ssh_channel_free(my_ssh_channel);
    ssh_disconnect(my_ssh_session);
    ssh_free(my_ssh_session);

    return 0;
}

这个示例代码使用 libssh 库连接到一个 SSH 服务器，并创建一个交互式的终端界面，用户可以输入命令并执行。需要注意的是，这只是一个简单的示例，实际的 WebSSH 实现需要更多的功能和特性。