/*
 * $Id: ssh2_exec.c,v 1.4 2009/05/07 20:30:22 bagder Exp $
 *
 * Sample showing how to use libssh2 to execute a command remotely.
 *
 * The sample code has fixed values for host name, user name, password
 * and command to run.
 *
 * Run it like this:
 *
 * $ ./ssh2_exec 127.0.0.1 user password "uptime"
 *
 */

#include "libssh2_config.h"
#include <libssh2.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_SYS_SELECT_H
# include <sys/select.h>
#endif
# ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_ARPA_INET_H
# include <arpa/inet.h>
#endif

#include <sys/time.h>
#include <sys/types.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>

static int waitsocket(int socket_fd, LIBSSH2_SESSION *session)
{
    struct timeval timeout;
    int rc;
    fd_set fd;
    fd_set *writefd = NULL;
    fd_set *readfd = NULL;
    int dir;

    timeout.tv_sec = 10;
    timeout.tv_usec = 0;

    FD_ZERO(&fd);

    FD_SET(socket_fd, &fd);

    /* now make sure we wait in the correct direction */
    dir = libssh2_session_block_directions(session);

    if(dir & LIBSSH2_SESSION_BLOCK_INBOUND)
        readfd = &fd;

    if(dir & LIBSSH2_SESSION_BLOCK_OUTBOUND)
        writefd = &fd;

    rc = select(socket_fd + 1, readfd, writefd, NULL, &timeout);

    return rc;
}

int main(int argc, char *argv[])
{
    const char *hostname = "127.0.0.1";
    const char *commandline = "cat";
    const char *username    = "user";
    const char *password    = "password";
    unsigned long hostaddr;
    int sock;
    struct sockaddr_in sin;
    const char *fingerprint;
    LIBSSH2_SESSION *session;
    LIBSSH2_CHANNEL *channel;
    int rc;
    int exitcode;
    char *exitsignal=(char *)"none";
    int bytecount = 0;
    size_t len;
    LIBSSH2_KNOWNHOSTS *nh;
    int type;

#ifdef WIN32
    WSADATA wsadata;
    WSAStartup(MAKEWORD(2,0), &wsadata);
#endif
    if (argc > 1)
        /* must be ip address only */
        hostname = argv[1];

    if (argc > 2) {
        username = argv[2];
    }
    if (argc > 3) {
        password = argv[3];
    }

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

    hostaddr = inet_addr(hostname);

    /* 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;
    }

    /* Create a session instance */
    session = libssh2_session_init();
    if (!session)
        return -1;

    /* tell libssh2 we want it all done 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;
    }

    nh = libssh2_knownhost_init(session);
    if(!nh) {
        /* eeek, do cleanup here */
        return 2;
    }

    /* read all hosts from here */
    libssh2_knownhost_readfile(nh, "known_hosts",
                               LIBSSH2_KNOWNHOST_FILE_OPENSSH);

    /* store all known hosts to here */
    libssh2_knownhost_writefile(nh, "dumpfile",
                                LIBSSH2_KNOWNHOST_FILE_OPENSSH);

    fingerprint = libssh2_session_hostkey(session, &len, &type);
    if(fingerprint) {
        struct libssh2_knownhost *host;
#if LIBSSH2_VERSION_NUM >= 0x010206
        /* introduced in 1.2.6 */
        int check = libssh2_knownhost_checkp(nh, hostname, 22,
                                             fingerprint, len,
                                             LIBSSH2_KNOWNHOST_TYPE_PLAIN|
                                             LIBSSH2_KNOWNHOST_KEYENC_RAW,
                                             &host);
#else
        /* 1.2.5 or older */
        int check = libssh2_knownhost_check(nh, hostname,
                                            fingerprint, len,
                                            LIBSSH2_KNOWNHOST_TYPE_PLAIN|
                                            LIBSSH2_KNOWNHOST_KEYENC_RAW,
                                            &host);
#endif
        fprintf(stderr, "Host check: %d, key: %s\n", check,
                (check <= LIBSSH2_KNOWNHOST_CHECK_MISMATCH)?
                host->key:"<none>");

        /*****
         * At this point, we could verify that 'check' tells us the key is
         * fine or bail out.
         *****/
    }
    else {
        /* eeek, do cleanup here */
        return 3;
    }
    libssh2_knownhost_free(nh);

    if ( strlen(password) != 0 ) {
        /* We could authenticate via password */
        while ((rc = libssh2_userauth_password(session, username, password)) ==
               LIBSSH2_ERROR_EAGAIN);
        if (rc) {
            fprintf(stderr, "Authentication by password failed.\n");
            exit(1);
        }
    }
    

#if 1
    libssh2_trace(session, LIBSSH2_TRACE_SOCKET);
#endif

    /* Exec non-blocking on the remove host */
    while( (channel = libssh2_channel_open_session(session)) == NULL &&
           libssh2_session_last_error(session,NULL,NULL,0) ==
           LIBSSH2_ERROR_EAGAIN )
    {
        waitsocket(sock, session);
    }
    if( channel == NULL )
    {
        fprintf(stderr,"Error\n");
        exit( 1 );
    }
    while( (rc = libssh2_channel_exec(channel, commandline)) ==
           LIBSSH2_ERROR_EAGAIN )
    {
        waitsocket(sock, session);
    }
    if( rc != 0 )
    {
        fprintf(stderr,"Error\n");
        exit( 1 );
    }
#if 0 
    for( ;; )
    {
        /* loop until we block */
        int rc;
        do
        {
            char buffer[0x4000];
            rc = libssh2_channel_read( channel, buffer, sizeof(buffer) );
            if( rc > 0 )
            {
                int i;
                bytecount += rc;
                fprintf(stderr, "We read:\n");
                for( i=0; i < rc; ++i )
                    fputc( buffer[i], stderr);
                fprintf(stderr, "\n");
            }
            else {
                fprintf(stderr, "libssh2_channel_read returned %d\n", rc);
            }
        }
        while( rc > 0 );

        /* this is due to blocking that would occur otherwise so we loop on
           this condition */
        if( rc == LIBSSH2_ERROR_EAGAIN )
        {
            waitsocket(sock, session);
        }
        else
            break;
    }
#endif

    
    LIBSSH2_POLLFD *fds = NULL;
    int running = 1;
    int bufsize = 32000;
    char buffer[bufsize];
    int totsize = 1500000;
    int totwritten = 0;
    int totread = 0;
    int partials = 0;
    int rereads = 0;
    int rewrites = 0;
    int i;

    for (i = 0; i < bufsize; i++)
        buffer[i] = 'A';

    if ((fds = malloc (sizeof (LIBSSH2_POLLFD))) == NULL) {
        fprintf(stderr, "malloc failed\n");
        exit(1);
    }

    fds[0].type = LIBSSH2_POLLFD_CHANNEL;
    fds[0].fd.channel = channel;
    fds[0].events = LIBSSH2_POLLFD_POLLIN | LIBSSH2_POLLFD_POLLOUT;

    do {
        int rc = (libssh2_poll(fds, 1, 10));
        //fprintf(stderr, "poll: %d\n", rc);

        if (rc < 1) 
            continue;
        
        int act = 0;
        //fprintf(stderr, "events: %d\n", fds[0].events);
        //fprintf(stderr, "revents: %d\n", fds[0].revents);

        if (fds[0].revents & LIBSSH2_POLLFD_POLLIN) {
           //fprintf(stderr, "CAN READ\n");
           act++;

           int n = libssh2_channel_read(channel, buffer, sizeof(buffer));

           if (n == LIBSSH2_ERROR_EAGAIN) {
               rereads++;
               fprintf(stderr, "will read again\n");
           } else if (n < 0) {
               fprintf(stderr, "read failed\n");
               exit(1);
           } else {
               totread += n;
               fprintf(stderr, "read %d bytes (%d in total)\n", n, totread);
           }
        }

        if (fds[0].revents & LIBSSH2_POLLFD_POLLOUT) {
           //fprintf(stderr, "CAN WRITE\n");
           act++;

           if (totwritten < totsize) {
               // we have not written all data yet
               int left = totsize - totwritten;
               int size = (left < bufsize) ? left : bufsize;
               int n = libssh2_channel_write_ex(channel, 0, buffer, size);

               if (n == LIBSSH2_ERROR_EAGAIN) {
                   rewrites++;
                   fprintf(stderr, "will write again\n");
               } else if (n < 0) {
                   fprintf(stderr, "write failed\n");
                   exit(1);
               } else {
                   totwritten += n;
                   fprintf(stderr, "wrote %d bytes (%d in total)", n, totwritten);
                   if (left >= bufsize && n != bufsize) {
                        partials++;
                        fprintf(stderr, " PARTIAL");
                   }
                    fprintf(stderr, "\n");
               }
           } else {
               // all data written, send EOF
               rc = libssh2_channel_send_eof(channel);

               if (rc == LIBSSH2_ERROR_EAGAIN) {
                   fprintf(stderr, "will send eof again\n");
               } else if (rc < 0) {
                   fprintf(stderr, "send eof failed\n");
                   exit(1);
               } else {
                   fprintf(stderr, "sent eof\n");
                   // we're done writing, stop listening for OUT events
                   fds[0].events &= ~LIBSSH2_POLLFD_POLLOUT;
               }
           }
        }

        if (fds[0].revents & LIBSSH2_POLLFD_CHANNEL_CLOSED) {
           //fprintf(stderr, "CLOSED\n");
           if (!act) // don't leave loop until we have read all data
                running = 0;
        }
    } while(running);

    exitcode = 127;
    while( (rc = libssh2_channel_close(channel)) == LIBSSH2_ERROR_EAGAIN )
        waitsocket(sock, session);

    if( rc == 0 )
    {
        exitcode = libssh2_channel_get_exit_status( channel );
        libssh2_channel_get_exit_signal(channel, &exitsignal,
                                        NULL, NULL, NULL, NULL, NULL);
    }

    if (exitsignal)
        printf("\nGot signal: %s\n", exitsignal);

    libssh2_channel_free(channel);
    channel = NULL;

    //fprintf(stderr, "partials: %d\n", partials);
    fprintf(stderr, "\nrereads: %d rewrites: %d\n", rereads, rewrites);

    if (totwritten != totread) {
        fprintf(stderr, "\n*** FAIL bytes written: %d bytes read: %d ***\n", totwritten, totread);
        exit(1);
    }

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;
}