libssh2

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/* Copyright (C) The libssh2 project and its contributors.
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 *
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 * Sample showing how to do SFTP transfers in a non-blocking manner.
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 *
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 * It will first download a given source file, store it locally and then
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 * upload the file again to a given destination file.
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 *
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 * Using the SFTP server running on 127.0.0.1
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 *
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 * SPDX-License-Identifier: BSD-3-Clause
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 */
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#include "libssh2_setup.h"
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#include <libssh2.h>
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#include <libssh2_sftp.h>
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#ifdef _WIN32
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#define write(f, b, c)  write((f), (b), (unsigned int)(c))
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#endif
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#ifdef HAVE_SYS_SOCKET_H
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#include <sys/socket.h>
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifdef HAVE_NETINET_IN_H
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#include <netinet/in.h>
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#endif
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#ifdef HAVE_SYS_TIME_H
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#include <sys/time.h>
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#endif
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#include <stdio.h>
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static const char *pubkey = "/home/username/.ssh/id_rsa.pub";
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static const char *privkey = "/home/username/.ssh/id_rsa";
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static const char *username = "username";
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static const char *password = "password";
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static const char *sftppath = "/tmp/TEST"; /* source path */
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static const char *dest = "/tmp/TEST2";    /* destination path */
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static const char *storage = "/tmp/sftp-storage"; /* local file name to store
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                                                     the downloaded file in */
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static int waitsocket(libssh2_socket_t socket_fd, LIBSSH2_SESSION *session)
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{
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    struct timeval timeout;
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    int rc;
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    fd_set fd;
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    fd_set *writefd = NULL;
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    fd_set *readfd = NULL;
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    int dir;
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    timeout.tv_sec = 10;
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    timeout.tv_usec = 0;
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    FD_ZERO(&fd);
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#if defined(__GNUC__)
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wsign-conversion"
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#endif
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    FD_SET(socket_fd, &fd);
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#if defined(__GNUC__)
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#pragma GCC diagnostic pop
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#endif
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    /* now make sure we wait in the correct direction */
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    dir = libssh2_session_block_directions(session);
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    if(dir & LIBSSH2_SESSION_BLOCK_INBOUND)
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        readfd = &fd;
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    if(dir & LIBSSH2_SESSION_BLOCK_OUTBOUND)
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        writefd = &fd;
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    rc = select((int)(socket_fd + 1), readfd, writefd, NULL, &timeout);
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    return rc;
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}
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int main(int argc, char *argv[])
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{
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    libssh2_socket_t sock;
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    int i, auth_pw = 1;
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    struct sockaddr_in sin;
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    const char *fingerprint;
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    int rc;
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    LIBSSH2_SESSION *session = NULL;
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    LIBSSH2_SFTP *sftp_session;
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    LIBSSH2_SFTP_HANDLE *sftp_handle;
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    FILE *tempstorage = NULL;
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    char mem[1000];
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    struct timeval timeout;
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    fd_set fd;
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    fd_set fd2;
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#ifdef _WIN32
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    WSADATA wsadata;
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    rc = WSAStartup(MAKEWORD(2, 0), &wsadata);
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    if(rc) {
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        fprintf(stderr, "WSAStartup failed with error: %d\n", rc);
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        return 1;
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    }
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#endif
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    if(argc > 1) {
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        username = argv[1];
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    }
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    if(argc > 2) {
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        password = argv[2];
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    }
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    if(argc > 3) {
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        sftppath = argv[3];
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    }
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    if(argc > 4) {
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        dest = argv[4];
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    }
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    rc = libssh2_init(0);
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    if(rc) {
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        fprintf(stderr, "libssh2 initialization failed (%d)\n", rc);
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        return 1;
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    }
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    /* Ultra basic "connect to port 22 on localhost".  Your code is
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     * responsible for creating the socket establishing the connection
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     */
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    sock = socket(AF_INET, SOCK_STREAM, 0);
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    if(sock == LIBSSH2_INVALID_SOCKET) {
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        fprintf(stderr, "failed to create socket.\n");
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        goto shutdown;
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    }
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    sin.sin_family = AF_INET;
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    sin.sin_port = htons(22);
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    sin.sin_addr.s_addr = htonl(0x7F000001);
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    if(connect(sock, (struct sockaddr*)(&sin), sizeof(struct sockaddr_in))) {
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        fprintf(stderr, "failed to connect.\n");
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        goto shutdown;
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    }
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    /* Create a session instance */
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    session = libssh2_session_init();
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    if(!session) {
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        fprintf(stderr, "Could not initialize SSH session.\n");
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        goto shutdown;
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    }
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    /* ... start it up. This will trade welcome banners, exchange keys,
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     * and setup crypto, compression, and MAC layers
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     */
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    rc = libssh2_session_handshake(session, sock);
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    if(rc) {
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        fprintf(stderr, "Failure establishing SSH session: %d\n", rc);
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        goto shutdown;
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    }
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    libssh2_session_set_blocking(session, 0);
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    /* At this point we have not yet authenticated.  The first thing to do
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     * is check the hostkey's fingerprint against our known hosts Your app
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     * may have it hard coded, may go to a file, may present it to the
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     * user, that's your call
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     */
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    fingerprint = libssh2_hostkey_hash(session, LIBSSH2_HOSTKEY_HASH_SHA1);
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    fprintf(stderr, "Fingerprint: ");
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    for(i = 0; i < 20; i++) {
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        fprintf(stderr, "%02X ", (unsigned char)fingerprint[i]);
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    }
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    fprintf(stderr, "\n");
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    tempstorage = fopen(storage, "wb");
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    if(!tempstorage) {
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        fprintf(stderr, "Cannot open temp storage file %s\n", storage);
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        goto shutdown;
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    }
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    if(auth_pw) {
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        /* We could authenticate via password */
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        while((rc = libssh2_userauth_password(session, username, password)) ==
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              LIBSSH2_ERROR_EAGAIN);
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        if(rc) {
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            fprintf(stderr, "Authentication by password failed.\n");
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            goto shutdown;
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        }
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    }
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    else {
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        /* Or by public key */
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        while((rc =
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              libssh2_userauth_publickey_fromfile(session, username,
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                                                  pubkey, privkey,
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                                                  password)) ==
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              LIBSSH2_ERROR_EAGAIN);
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        if(rc) {
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            fprintf(stderr, "Authentication by public key failed.\n");
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            goto shutdown;
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        }
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    }
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    do {
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        sftp_session = libssh2_sftp_init(session);
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        if(!sftp_session) {
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            if(libssh2_session_last_errno(session) == LIBSSH2_ERROR_EAGAIN) {
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                fprintf(stderr, "non-blocking init\n");
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                waitsocket(sock, session); /* now we wait */
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            }
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            else {
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                fprintf(stderr, "Unable to init SFTP session\n");
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                goto shutdown;
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            }
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        }
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    } while(!sftp_session);
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    /* Request a file via SFTP */
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    do {
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        sftp_handle = libssh2_sftp_open(sftp_session, sftppath,
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                                        LIBSSH2_FXF_READ, 0);
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        if(!sftp_handle) {
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            if(libssh2_session_last_errno(session) != LIBSSH2_ERROR_EAGAIN) {
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                fprintf(stderr, "Unable to open file with SFTP: %ld\n",
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                        libssh2_sftp_last_error(sftp_session));
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                goto shutdown;
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            }
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            else {
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                fprintf(stderr, "non-blocking open\n");
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                waitsocket(sock, session); /* now we wait */
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            }
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        }
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    } while(!sftp_handle);
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    fprintf(stderr, "libssh2_sftp_open() is done, now receive data.\n");
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    do {
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        ssize_t nread;
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        do {
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            /* read in a loop until we block */
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            nread = libssh2_sftp_read(sftp_handle, mem, sizeof(mem));
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            fprintf(stderr, "libssh2_sftp_read returned %ld\n",
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                    (long)nread);
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            if(nread > 0) {
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                /* write to stderr */
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                write(2, mem, (size_t)nread);
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                /* write to temporary storage area */
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                fwrite(mem, (size_t)nread, 1, tempstorage);
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            }
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        } while(nread > 0);
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        if(nread != LIBSSH2_ERROR_EAGAIN) {
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            /* error or end of file */
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            break;
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        }
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        timeout.tv_sec = 10;
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        timeout.tv_usec = 0;
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        FD_ZERO(&fd);
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        FD_ZERO(&fd2);
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#if defined(__GNUC__)
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wsign-conversion"
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#endif
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        FD_SET(sock, &fd);
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        FD_SET(sock, &fd2);
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#if defined(__GNUC__)
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#pragma GCC diagnostic pop
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#endif
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        /* wait for readable or writeable */
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        rc = select((int)(sock + 1), &fd, &fd2, NULL, &timeout);
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        if(rc <= 0) {
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            /* negative is error
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               0 is timeout */
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            fprintf(stderr, "SFTP download timed out: %d\n", rc);
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            break;
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        }
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    } while(1);
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    libssh2_sftp_close(sftp_handle);
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    fclose(tempstorage);
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    tempstorage = fopen(storage, "rb");
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    if(!tempstorage) {
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        /* weird, we cannot read the file we just wrote to... */
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        fprintf(stderr, "Cannot open %s for reading\n", storage);
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        goto shutdown;
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    }
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    /* we're done downloading, now reverse the process and upload the
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       temporarily stored data to the destination path */
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    sftp_handle = libssh2_sftp_open(sftp_session, dest,
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                                    LIBSSH2_FXF_WRITE |
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                                    LIBSSH2_FXF_CREAT,
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                                    LIBSSH2_SFTP_S_IRUSR |
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                                    LIBSSH2_SFTP_S_IWUSR |
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                                    LIBSSH2_SFTP_S_IRGRP |
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                                    LIBSSH2_SFTP_S_IROTH);
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    if(sftp_handle) {
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        size_t nread;
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        char *ptr;
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        do {
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            ssize_t nwritten;
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            nread = fread(mem, 1, sizeof(mem), tempstorage);
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            if(nread <= 0) {
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                /* end of file */
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                break;
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            }
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            ptr = mem;
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            do {
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                /* write data in a loop until we block */
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                nwritten = libssh2_sftp_write(sftp_handle, ptr,
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                                              nread);
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                if(nwritten < 0)
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                    break;
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                ptr += nwritten;
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                nread -= (size_t)nwritten;
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            } while(nwritten >= 0);
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            if(nwritten != LIBSSH2_ERROR_EAGAIN) {
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                /* error or end of file */
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                break;
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            }
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328
            timeout.tv_sec = 10;
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            timeout.tv_usec = 0;
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331
            FD_ZERO(&fd);
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            FD_ZERO(&fd2);
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#if defined(__GNUC__)
334
#pragma GCC diagnostic push
335
#pragma GCC diagnostic ignored "-Wsign-conversion"
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#endif
337
            FD_SET(sock, &fd);
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            FD_SET(sock, &fd2);
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#if defined(__GNUC__)
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#pragma GCC diagnostic pop
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#endif
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            /* wait for readable or writeable */
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            rc = select((int)(sock + 1), &fd, &fd2, NULL, &timeout);
345
            if(rc <= 0) {
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                /* negative is error
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                   0 is timeout */
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                fprintf(stderr, "SFTP upload timed out: %d\n", rc);
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                break;
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            }
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        } while(1);
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        fprintf(stderr, "SFTP upload done.\n");
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    }
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    else {
355
        fprintf(stderr, "SFTP failed to open destination path: %s\n",
356
                dest);
357
    }
358

359
    libssh2_sftp_shutdown(sftp_session);
360

361
shutdown:
362

363
    if(session) {
364
        libssh2_session_disconnect(session, "Normal Shutdown");
365
        libssh2_session_free(session);
366
    }
367

368
    if(sock != LIBSSH2_INVALID_SOCKET) {
369
        shutdown(sock, 2);
370
        LIBSSH2_SOCKET_CLOSE(sock);
371
    }
372

373
    if(tempstorage)
374
        fclose(tempstorage);
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376
    fprintf(stderr, "all done\n");
377

378
    libssh2_exit();
379

380
#ifdef _WIN32
381
    WSACleanup();
382
#endif
383

384
    return 0;
385
}
386