/* * Sample showing how to do SSH2 connect using ssh-agent. * * The sample code has default values for host name, user name: * * "ssh2_agent host user" */ #include "libssh2_config.h"#include <libssh2.h>#include <libssh2_sftp.h> #ifdef HAVE_WINDOWS_H# include <windows.h>#endif#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 #include <sys/types.h>#include <fcntl.h>#include <errno.h>#include <stdio.h>#include <ctype.h>#include <stdlib.h> const char *username="username"; int main(int argc, char *argv[]){    unsigned long hostaddr;    int sock = -1, i, rc;    struct sockaddr_in sin;    const char *fingerprint;    char *userauthlist;    LIBSSH2_SESSION *session = NULL;    LIBSSH2_CHANNEL *channel;    LIBSSH2_AGENT *agent = NULL;    struct libssh2_agent_publickey *identity, *prev_identity = NULL;#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];    }     rc = libssh2_init (0);    if (rc != 0) {        fprintf (stderr, "libssh2 initialization failed (%d)\n", rc);        return 1;    }     /* Ultra basic "connect to port 22 on localhost".  Your code is     * responsible for creating the socket establishing the connection     */    sock = socket(AF_INET, SOCK_STREAM, 0);    if (sock == -1) {        fprintf(stderr, "failed to create socket!\n");        rc = 1;        goto shutdown;    }     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");        goto shutdown;    }     /* Create a session instance and start it up. This will trade welcome     * banners, exchange keys, and setup crypto, compression, and MAC layers     */    session = libssh2_session_init();    if (libssh2_session_handshake(session, sock)) {        fprintf(stderr, "Failure establishing SSH session\n");        return 1;    }     /* At this point we havn't 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));    fprintf(stderr, "Authentication methods: %s\n", userauthlist);    if (strstr(userauthlist, "publickey") == NULL) {        fprintf(stderr, "\"publickey\" authentication is not supported\n");        goto shutdown;    }     /* Connect to the ssh-agent */    agent = libssh2_agent_init(session);    if (!agent) {        fprintf(stderr, "Failure initializing ssh-agent support\n");        rc = 1;        goto shutdown;    }    if (libssh2_agent_connect(agent)) {        fprintf(stderr, "Failure connecting to ssh-agent\n");        rc = 1;        goto shutdown;    }    if (libssh2_agent_list_identities(agent)) {        fprintf(stderr, "Failure requesting identities to ssh-agent\n");        rc = 1;        goto shutdown;    }    while (1) {        rc = libssh2_agent_get_identity(agent, &identity, prev_identity);        if (rc == 1)            break;        if (rc < 0) {            fprintf(stderr,                    "Failure obtaining identity from ssh-agent support\n");            rc = 1;            goto shutdown;        }        if (libssh2_agent_userauth(agent, username, identity)) {            fprintf(stderr, "\tAuthentication with username %s and "                   "public key %s failed!\n",                   username, identity->comment);        } else {            fprintf(stderr, "\tAuthentication with username %s and "                   "public key %s succeeded!\n",                   username, identity->comment);            break;        }        prev_identity = identity;    }    if (rc) {        fprintf(stderr, "Couldn't continue authentication\n");        goto shutdown;    }     /* We're authenticated now. */     /* Request a shell */    if (!(channel = libssh2_channel_open_session(session))) {        fprintf(stderr, "Unable to open a session\n");        goto shutdown;    }     /* Some environment variables may be set,     * It's up to the server which ones it'll allow though     */    libssh2_channel_setenv(channel, "FOO", "bar");     /* Request a terminal with 'vanilla' terminal emulation     * See /etc/termcap for more options     */    if (libssh2_channel_request_pty(channel, "vanilla")) {        fprintf(stderr, "Failed requesting pty\n");        goto skip_shell;    }     /* Open a SHELL on that pty */    if (libssh2_channel_shell(channel)) {        fprintf(stderr, "Unable to request shell on allocated pty\n");        goto shutdown;    }     /* At this point the shell can be interacted with using     * libssh2_channel_read()     * libssh2_channel_read_stderr()     * libssh2_channel_write()     * libssh2_channel_write_stderr()     *     * Blocking mode may be (en|dis)abled with: libssh2_channel_set_blocking()     * If the server send EOF, libssh2_channel_eof() will return non-0     * To send EOF to the server use: libssh2_channel_send_eof()     * A channel can be closed with: libssh2_channel_close()     * A channel can be freed with: libssh2_channel_free()     */   skip_shell:    if (channel) {        libssh2_channel_free(channel);        channel = NULL;    }     /* Other channel types are supported via:     * libssh2_scp_send()     * libssh2_scp_recv()     * libssh2_channel_direct_tcpip()     */   shutdown:     libssh2_agent_disconnect(agent);    libssh2_agent_free(agent);     if(session) {        libssh2_session_disconnect(session,                                   "Normal Shutdown, Thank you for playing");        libssh2_session_free(session);    }     if (sock != -1) {#ifdef WIN32        closesocket(sock);#else        close(sock);#endif    }     fprintf(stderr, "all done!\n");     libssh2_exit();     return rc;}