libssh2/example/simple/scp_nonblock.c

/*
 * $Id: scp_nonblock.c,v 1.4 2007/06/06 12:34:08 jehousley Exp $
 *
 * Sample showing how to do SCP transfers in a non-blocking manner.
 */

#include <libssh2.h>
#include <libssh2_config.h>

#ifdef HAVE_WINSOCK2_H
# include <winsock2.h>
#endif
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
# include <sys/socket.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>

int main(int argc, char *argv[])
{
    unsigned long hostaddr;
    int sock, i, auth_pw = 1;
    struct sockaddr_in sin;
    const char *fingerprint;
    LIBSSH2_SESSION *session;
    LIBSSH2_CHANNEL *channel;
    char *username=(char *)"username";
    char *password=(char *)"password";
    char *scppath=(char *)"/tmp/TEST";
    struct stat fileinfo;
    int rc;
    off_t got=0;
    
#ifdef WIN32
    WSADATA wsadata;
    
    WSAStartup(WINSOCK_VERSION, &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) {
        scppath = argv[4];
    }
    
    /* 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);
    
    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;
    }
    
    /* We set the socket non-blocking. We do it after the connect just to
        simplify the example code. */
#ifdef F_SETFL
    /* FIXME: this can/should be done in a more portable manner */
    rc = fcntl(sock, F_GETFL, 0);
    fcntl(sock, F_SETFL, rc | O_NONBLOCK);
#else
#error "add support for setting the socket non-blocking here"
#endif
    
    /* Create a session instance */
    session = libssh2_session_init();
    if (!session)
        return -1;
    
    /* Since we have set non-blocking, tell libssh2 we are non-blocking */
    libssh2_session_set_blocking(session, 0);
    
    /* ... start it up. This will trade welcome banners, exchange keys,
     * and setup crypto, compression, and MAC layers
     */
    while ((rc = libssh2_session_startup(session, sock)) == LIBSSH2_ERROR_EAGAIN);
    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_MD5);
    fprintf(stderr, "Fingerprint: ");
    for(i = 0; i < 16; i++) {
        fprintf(stderr, "%02X ", (unsigned char)fingerprint[i]);
    }
    fprintf(stderr, "\n");
    
    if (auth_pw) {
        /* We could authenticate via password */
        while ((rc = libssh2_userauth_password(session, username, password)) == LIBSSH2CHANNEL_EAGAIN);
    if (rc) {
            fprintf(stderr, "Authentication by password failed.\n");
            goto shutdown;
        }
    } else {
        /* Or by public key */
        while ((rc = libssh2_userauth_publickey_fromfile(session, username,
                                                         "/home/username/.ssh/id_rsa.pub",
                                                         "/home/username/.ssh/id_rsa",
                                                         password)) == LIBSSH2CHANNEL_EAGAIN);
    if (rc) {
            fprintf(stderr, "\tAuthentication by public key failed\n");
            goto shutdown;
        }
    }
    
    /* Request a file via SCP */
    fprintf(stderr, "libssh2_scp_recv()!\n");
    do {
        channel = libssh2_scp_recv(session, scppath, &fileinfo);
        
        if ((!channel) && (libssh2_session_last_errno(session) != LIBSSH2_ERROR_EAGAIN)) {
            fprintf(stderr, "Unable to open a session\n");
            goto shutdown;
        }
    } while (!channel);
    fprintf(stderr, "libssh2_scp_recv() is done, now receive data!\n");
    
    while(got < fileinfo.st_size) {
        char mem[1000];
        
        struct timeval timeout;
        int rc;
        fd_set fd;
        
        do {
            int amount=sizeof(mem);
            
            if ((fileinfo.st_size -got) < amount) {
                amount = fileinfo.st_size - got;
            }
            
            /* loop until we block */
            rc = libssh2_channel_read(channel, mem, amount);
            if (rc > 0) {
                write(1, mem, rc);
                got += rc;
            }
        } while (rc > 0);
        
        if (rc == LIBSSH2CHANNEL_EAGAIN) {
            /* this is due to blocking that would occur otherwise
            so we loop on this condition */
            
            timeout.tv_sec = 10;
            timeout.tv_usec = 0;
            
            FD_ZERO(&fd);
            
            FD_SET(sock, &fd);
            
            rc = select(sock+1, &fd, &fd, NULL, &timeout);
            if (rc <= 0) {
                /* negative is error
                0 is timeout */
                fprintf(stderr, "SCP timed out: %d\n", rc);
            }
            continue;
        }
        break;
    }
    
    libssh2_channel_free(channel);
    channel = NULL;
    
shutdown:
        
    libssh2_session_disconnect(session, "Normal Shutdown, Thank you for playing");
    libssh2_session_free(session);
    
#ifdef WIN32
    Sleep(1000);
    closesocket(sock);
#else
    sleep(1);
    close(sock);
#endif
    fprintf(stderr, "all done\n");
    return 0;
}