使用libssh2库实现支持密码参数的ssh2客户端

/*
 *    可以使用密码参数的 SSH 客户端程序 v1.0
 * Copyright (c) 2011 Niu.Chenguang <[e-mail]>
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * [makefile]
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * CFLAGS=-Wall -c -g
 * LDFLAGS=-Wall -lssh2
 * OBJS=jnSSH2.o
 *
 * jnSSH2: $(OBJS)
 *     gcc $(LDFLAGS) $< -o $@
 *
 * %.o: %.c
 *     gcc $(CFLAGS) -o $@ $^
 *
 * install: jnSSH2
 *     sudo cp ./jnSSH2 /usr/bin/
 *
 * clean:
 *     rm -f jnSSH2
 *     rm -f $(OBJS)
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * [README]
 * 一、ubuntu 编译并使用
 * 1、安装 libssh2-dev 库
 *     sudo aptitued install libssh2-1-dev
 * 2、编译
 *     make
 * 3、测试
 *     ./jnSSH2 ip port user passwd
 * 4、安装
 *     make install
 */

#include <string.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/types.h>
#include <libgen.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <termios.h>

#include <libssh2.h>

#define COPYRIGHT "jnSSH2 v1.0\nCopyright (C) 2011 Niu.Chenguang \n\n"

struct termios _saved_tio;
int tio_saved = 0;

static int _raw_mode(void)
{
    int rc;
    struct termios tio;

    rc = tcgetattr(fileno(stdin), &tio);
    if (rc != -1) {
        _saved_tio = tio;
        tio_saved = 1;
        cfmakeraw(&tio);
        rc = tcsetattr(fileno(stdin), TCSADRAIN, &tio);
    }

    return rc;
}

static int _normal_mode(void)
{
    if (tio_saved)
        return tcsetattr(fileno(stdin), TCSADRAIN, &_saved_tio);

    return 0;
}

int main (int argc, char *argv[])
{
    int sock = 0;
    unsigned long hostaddr = 0;
    short port = 22;
    char *username = NULL;
    char *password = NULL;
    struct sockaddr_in sin;
    LIBSSH2_SESSION *session;
    LIBSSH2_CHANNEL *channel;
    int nfds = 1;
    char buf;
    LIBSSH2_POLLFD *fds = NULL;

    /* Struct winsize for term size */
    struct winsize w_size;
    struct winsize w_size_bck;

    /* For select on stdin */
    fd_set set;
    struct timeval timeval_out;
    timeval_out.tv_sec = 0;
    timeval_out.tv_usec = 10;

    printf(COPYRIGHT);

    if (argc > 4) {
        hostaddr = inet_addr(argv[1]);
        port = htons(atoi(argv[2]));
        username = argv[3];
        password = argv[4];
    }
    else {
        fprintf(stderr, "Usage: %s ip port user password\n", basename(argv[0]));
        return -1;
    }

    if (libssh2_init (0) != 0) {
        fprintf (stderr, "libssh2 initialization failed\n");
        return -1;
    }

    sock = socket (AF_INET, SOCK_STREAM, 0);
    sin.sin_family = AF_INET;
    sin.sin_port = port;
    sin.sin_addr.s_addr = hostaddr;
    if (connect(sock, (struct sockaddr *) &sin, sizeof(struct sockaddr_in)) != 0) {
        fprintf (stderr, "Failed to established connection!\n");
        return -1;
    }

    /* Open a session */
    session = libssh2_session_init();
    if (libssh2_session_startup (session, sock) != 0) {
        fprintf(stderr, "Failed Start the SSH session\n");
        return -1;
    }

    /* Authenticate via password */
    if (libssh2_userauth_password(session, username, password) != 0) {
        fprintf(stderr, "Failed to authenticate\n");
        close(sock);
        goto ERROR;
    }

    /* Open a channel */
    channel  = libssh2_channel_open_session(session);

    if ( channel == NULL ) {
        fprintf(stderr, "Failed to open a new channel\n");
        close(sock);
        goto ERROR;
    }

    /* Request a PTY */
    if (libssh2_channel_request_pty( channel, "xterm") != 0) {
        fprintf(stderr, "Failed to request a pty\n");
        close(sock);
        goto ERROR;
    }

    /* Request a shell */
    if (libssh2_channel_shell(channel) != 0) {
        fprintf(stderr, "Failed to open a shell\n");
        close(sock);
        goto ERROR;
    }

    if (_raw_mode() != 0) {
        fprintf(stderr, "Failed to entered in raw mode\n");
        close(sock);
        goto ERROR;
    }

    while (1) {
        FD_ZERO(&set);
        FD_SET(fileno(stdin),&set);

        ioctl(fileno(stdin), TIOCGWINSZ, &w_size);
        if ((w_size.ws_row != w_size_bck.ws_row) ||
            (w_size.ws_col != w_size_bck.ws_col)) {
            w_size_bck = w_size;
            libssh2_channel_request_pty_size(channel, w_size.ws_col, w_size.ws_row);
        }

        if ((fds = malloc (sizeof (LIBSSH2_POLLFD))) == NULL)
            break;

        fds[0].type = LIBSSH2_POLLFD_CHANNEL;
        fds[0].fd.channel = channel;
        fds[0].events = LIBSSH2_POLLFD_POLLIN;
        fds[0].revents = LIBSSH2_POLLFD_POLLIN;

        if (libssh2_poll(fds, nfds, 0) >0) {
            libssh2_channel_read(channel, &buf, 1);
            fprintf(stdout, "%c", buf);
            fflush(stdout);
        }

        if (select(fileno(stdin)+1,&set,NULL,NULL,&timeval_out) > 0)
            if (read(fileno(stdin), &buf, 1) > 0)
                libssh2_channel_write(channel, &buf, 1);

        free (fds);

        if (libssh2_channel_eof(channel) == 1)
          break;
    }

    if (channel) {
        libssh2_channel_free (channel);
        channel = NULL;
    }

    _normal_mode();

    libssh2_exit();

    return 0;
ERROR:
    libssh2_session_disconnect(session, "Session Shutdown, Thank you for playing");
    libssh2_session_free(session);
    return -1;
}