使用 libssh2 进行 SFTP 文件传输

/*
 * Sample showing how to do SFTP transfers.
 *
 * The sample code has default values for host name, user name, password
 * and path to copy, but you can specify them on the command line like:
 *
 * "sftp 192.168.0.1 user password /tmp/secrets -p|-i|-k"
 */ 
 
#include "libssh2_config.h"
#include <libssh2.h>
#include <libssh2_sftp.h>
 
#ifdef HAVE_WINSOCK2_H
#include <winsock2.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
 
#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
 
 
const char *keyfile1="~/.ssh/id_rsa.pub";
const char *keyfile2="~/.ssh/id_rsa";
const char *username="username";
const char *password="password";
const char *sftppath="/tmp/TEST";
 
 
static void kbd_callback(const char *name, int name_len,
             const char *instruction, int instruction_len, int num_prompts,
             const LIBSSH2_USERAUTH_KBDINT_PROMPT *prompts,
             LIBSSH2_USERAUTH_KBDINT_RESPONSE *responses,
             void **abstract)
{
    int i;
    size_t n;
    char buf[1024];
    (void)abstract;
 
    printf("Performing keyboard-interactive authentication.\n");
 
    printf("Authentication name: '");
    fwrite(name, 1, name_len, stdout);
    printf("'\n");
 
    printf("Authentication instruction: '");
    fwrite(instruction, 1, instruction_len, stdout);
    printf("'\n");
 
    printf("Number of prompts: %d\n\n", num_prompts);
 
    for (i = 0; i < num_prompts; i++) {
        printf("Prompt %d from server: '", i);
        fwrite(prompts[i].text, 1, prompts[i].length, stdout);
        printf("'\n");
 
        printf("Please type response: ");
        fgets(buf, sizeof(buf), stdin);
        n = strlen(buf);
        while (n > 0 && strchr("\r\n", buf[n - 1]))
          n--;
        buf[n] = 0;
 
        responses[i].text = strdup(buf);
        responses[i].length = n;
 
        printf("Response %d from user is '", i);
        fwrite(responses[i].text, 1, responses[i].length, stdout);
        printf("'\n\n");
    }
 
    printf("Done. Sending keyboard-interactive responses to server now.\n");
}
 
 
int main(int argc, char *argv[])
{
    unsigned long hostaddr;
    int sock, i, auth_pw = 0;
    struct sockaddr_in sin;
    const char *fingerprint;
    char *userauthlist;
    LIBSSH2_SESSION *session;
    int rc;
    LIBSSH2_SFTP *sftp_session;
    LIBSSH2_SFTP_HANDLE *sftp_handle;
 
#ifdef WIN32
    WSADATA wsadata;
 
    WSAStartup(MAKEWORD(2,0), &wsadata);
#endif
 
    if (argc > 1) {
        hostaddr = inet_addr(argv[1]);
    } else {
        hostaddr = htonl(0x7F000001);
    }
 
    if(argc > 2) {
        username = argv[2];
    }
    if(argc > 3) {
        password = argv[3];
    }
    if(argc > 4) {
        sftppath = argv[4];
    }
 
    rc = libssh2_init (0);

    if (rc != 0) {
        fprintf (stderr, "libssh2 initialization failed (%d)\n", rc);
        return 1;
    }
 
    /*
     * The application code is responsible for creating the socket
     * and establishing the connection
     */ 
    sock = socket(AF_INET, SOCK_STREAM, 0);
 
    sin.sin_family = AF_INET;
    sin.sin_port = htons(22);
    sin.sin_addr.s_addr = hostaddr;
    if (connect(sock, (struct sockaddr*)(&sin),
                sizeof(struct sockaddr_in)) != 0) {
        fprintf(stderr, "failed to connect!\n");
        return -1;
    }
 
    /* Create a session instance
     */ 
    session = libssh2_session_init();

    if(!session)
        return -1;
 
    /* Since we have set non-blocking, tell libssh2 we are blocking */ 
    libssh2_session_set_blocking(session, 1);

 
    /* ... start it up. This will trade welcome banners, exchange keys,
     * and setup crypto, compression, and MAC layers
     */ 
    rc = libssh2_session_handshake(session, sock);

    if(rc) {
        fprintf(stderr, "Failure establishing SSH session: %d\n", rc);
        return -1;
    }
 
    /* At this point we havn't yet authenticated.  The first thing to do
     * is check the hostkey's fingerprint against our known hosts Your app
     * may have it hard coded, may go to a file, may present it to the
     * user, that's your call
     */ 
    fingerprint = libssh2_hostkey_hash(session, LIBSSH2_HOSTKEY_HASH_SHA1);

    fprintf(stderr, "Fingerprint: ");
    for(i = 0; i < 20; i++) {
        fprintf(stderr, "%02X ", (unsigned char)fingerprint[i]);
    }
    fprintf(stderr, "\n");
 
    /* check what authentication methods are available */ 
    userauthlist = libssh2_userauth_list(session, username, strlen(username));

    printf("Authentication methods: %s\n", userauthlist);
    if (strstr(userauthlist, "password") != NULL) {
        auth_pw |= 1;
    }
    if (strstr(userauthlist, "keyboard-interactive") != NULL) {
        auth_pw |= 2;
    }
    if (strstr(userauthlist, "publickey") != NULL) {
        auth_pw |= 4;
    }
 
    /* if we got an 4. argument we set this option if supported */ 
    if(argc > 5) {
        if ((auth_pw & 1) && !strcasecmp(argv[5], "-p")) {
            auth_pw = 1;
        }
        if ((auth_pw & 2) && !strcasecmp(argv[5], "-i")) {
            auth_pw = 2;
        }
        if ((auth_pw & 4) && !strcasecmp(argv[5], "-k")) {
            auth_pw = 4;
        }
    }
 
    if (auth_pw & 1) {
        /* We could authenticate via password */ 
        if (libssh2_userauth_password(session, username, password)) {

            fprintf(stderr, "Authentication by password failed.\n");
            goto shutdown;
        }
    } else if (auth_pw & 2) {
        /* Or via keyboard-interactive */ 
        if (libssh2_userauth_keyboard_interactive(session, username, &kbd_callback) ) {

            printf("\tAuthentication by keyboard-interactive failed!\n");
            goto shutdown;
        } else {
            printf("\tAuthentication by keyboard-interactive succeeded.\n");
        }
    } else if (auth_pw & 4) {
        /* Or by public key */ 
        if (libssh2_userauth_publickey_fromfile(session, username, keyfile1, keyfile2, password)) {

            printf("\tAuthentication by public key failed!\n");
            goto shutdown;
        } else {
            printf("\tAuthentication by public key succeeded.\n");
        }
    } else {
        printf("No supported authentication methods found!\n");
        goto shutdown;
    }
 
    fprintf(stderr, "libssh2_sftp_init()!\n");

    sftp_session = libssh2_sftp_init(session);

 
    if (!sftp_session) {
        fprintf(stderr, "Unable to init SFTP session\n");
        goto shutdown;
    }
 
    fprintf(stderr, "libssh2_sftp_open()!\n");

    /* Request a file via SFTP */ 
    sftp_handle =
        libssh2_sftp_open(sftp_session, sftppath, LIBSSH2_FXF_READ, 0);

 
    if (!sftp_handle) {
        fprintf(stderr, "Unable to open file with SFTP: %ld\n",
                libssh2_sftp_last_error(sftp_session));

        goto shutdown;
    }
    fprintf(stderr, "libssh2_sftp_open() is done, now receive data!\n");

    do {
        char mem[1024];
 
        /* loop until we fail */ 
        fprintf(stderr, "libssh2_sftp_read()!\n");

        rc = libssh2_sftp_read(sftp_handle, mem, sizeof(mem));

        if (rc > 0) {
            write(1, mem, rc);
        } else {
            break;
        }
    } while (1);
 
    libssh2_sftp_close(sftp_handle);

    libssh2_sftp_shutdown(sftp_session);

 
  shutdown:
 
    libssh2_session_disconnect(session, "Normal Shutdown, Thank you for playing");

    libssh2_session_free(session);

 
#ifdef WIN32
    closesocket(sock);
#else
    close(sock);
#endif
    fprintf(stderr, "all done\n");
 
    libssh2_exit();

 
    return 0;
}