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 SCP transfers in a non-blocking manner.
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 *
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 * The sample code has default values for host name, user name, password
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 * and path to copy, but you can specify them on the command line like:
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 *
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 * $ ./scp_nonblock 192.168.0.1 user password /tmp/secrets
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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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#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_ARPA_INET_H
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#include <arpa/inet.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 *scppath = "/tmp/TEST";
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#ifdef HAVE_GETTIMEOFDAY
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/* diff in ms */
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static long tvdiff(struct timeval newer, struct timeval older)
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{
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    return (newer.tv_sec - older.tv_sec) * 1000 +
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        (newer.tv_usec - older.tv_usec) / 1000;
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}
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#endif
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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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    uint32_t hostaddr;
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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_CHANNEL *channel;
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    libssh2_struct_stat fileinfo;
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#ifdef HAVE_GETTIMEOFDAY
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    struct timeval start;
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    struct timeval end;
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    long time_ms;
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#endif
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    int spin = 0;
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    libssh2_struct_stat_size got = 0;
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    libssh2_struct_stat_size total = 0;
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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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        hostaddr = inet_addr(argv[1]);
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    }
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    else {
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        hostaddr = htonl(0x7F000001);
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    }
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    if(argc > 2) {
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        username = argv[2];
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    }
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    if(argc > 3) {
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        password = argv[3];
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    }
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    if(argc > 4) {
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        scppath = 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 = hostaddr;
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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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    /* Since we have set non-blocking, tell libssh2 we are non-blocking */
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    libssh2_session_set_blocking(session, 0);
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#ifdef HAVE_GETTIMEOFDAY
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    gettimeofday(&start, NULL);
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#endif
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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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    while((rc = libssh2_session_handshake(session, sock)) ==
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          LIBSSH2_ERROR_EAGAIN);
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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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    /* 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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    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 = 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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#if 0
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    libssh2_trace(session, LIBSSH2_TRACE_CONN);
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#endif
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    /* Request a file via SCP */
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    fprintf(stderr, "libssh2_scp_recv2().\n");
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    do {
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        channel = libssh2_scp_recv2(session, scppath, &fileinfo);
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        if(!channel) {
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            if(libssh2_session_last_errno(session) != LIBSSH2_ERROR_EAGAIN) {
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                char *err_msg;
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                libssh2_session_last_error(session, &err_msg, NULL, 0);
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                fprintf(stderr, "%s\n", err_msg);
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                goto shutdown;
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            }
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            else {
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                fprintf(stderr, "libssh2_scp_recv2() spin\n");
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                waitsocket(sock, session);
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            }
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        }
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    } while(!channel);
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    fprintf(stderr, "libssh2_scp_recv2() is done, now receive data.\n");
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    while(got < fileinfo.st_size) {
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        char mem[1024 * 24];
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        ssize_t nread;
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        do {
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            int amount = sizeof(mem);
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            if((fileinfo.st_size - got) < amount) {
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                amount = (int)(fileinfo.st_size - got);
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            }
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            /* loop until we block */
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            nread = libssh2_channel_read(channel, mem, (size_t)amount);
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            if(nread > 0) {
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                write(1, mem, (size_t)nread);
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                got += nread;
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                total += nread;
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            }
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        } while(nread > 0);
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        if(nread == LIBSSH2_ERROR_EAGAIN && got < fileinfo.st_size) {
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            /* this is due to blocking that would occur otherwise
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            so we loop on this condition */
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            spin++;
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            waitsocket(sock, session); /* now we wait */
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            continue;
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        }
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        break;
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    }
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#ifdef HAVE_GETTIMEOFDAY
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    gettimeofday(&end, NULL);
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    time_ms = tvdiff(end, start);
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    fprintf(stderr, "Got %ld bytes in %ld ms = %.1f bytes/sec spin: %d\n",
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            (long)total, time_ms,
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            (double)total / ((double)time_ms / 1000.0), spin);
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#else
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    fprintf(stderr, "Got %ld bytes spin: %d\n", (long)total, spin);
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#endif
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    libssh2_channel_free(channel);
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    channel = NULL;
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shutdown:
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    if(session) {
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        libssh2_session_disconnect(session, "Normal Shutdown");
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        libssh2_session_free(session);
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    }
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    if(sock != LIBSSH2_INVALID_SOCKET) {
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        shutdown(sock, 2);
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        LIBSSH2_SOCKET_CLOSE(sock);
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    }
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    fprintf(stderr, "all done\n");
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    libssh2_exit();
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#ifdef _WIN32
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    WSACleanup();
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#endif
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    return 0;
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}
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