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https://github.com/libssh2/libssh2.git
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7027604505
Also: - switch to non-deprecated alternative in examples. - add pointers and deprecation warning to libssh2_scp_send man page. Cherry-picked from #1484
365 lines
11 KiB
C
365 lines
11 KiB
C
/* Copyright (C) The libssh2 project and its contributors.
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*
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* Sample showing how to do SSH2 connect.
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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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* $ ./ssh2 hostip user password [[-p|-i|-k] [command]]
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*
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* -p authenticate using password
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* -i authenticate using keyboard-interactive
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* -k authenticate using public key (password argument decrypts keyfile)
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* command executes on the remote machine
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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 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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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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static const char *pubkey = ".ssh/id_rsa.pub";
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static const char *privkey = ".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 void kbd_callback(const char *name, int name_len,
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const char *instruction, int instruction_len,
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int num_prompts,
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const LIBSSH2_USERAUTH_KBDINT_PROMPT *prompts,
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LIBSSH2_USERAUTH_KBDINT_RESPONSE *responses,
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void **abstract)
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{
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(void)name;
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(void)name_len;
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(void)instruction;
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(void)instruction_len;
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if(num_prompts == 1) {
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responses[0].text = strdup(password);
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responses[0].length = (unsigned int)strlen(password);
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}
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(void)prompts;
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(void)abstract;
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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 = 0;
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struct sockaddr_in sin;
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const char *fingerprint;
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char *userauthlist;
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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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#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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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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rc = 1;
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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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fprintf(stderr, "Connecting to %s:%d as user %s\n",
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inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), username);
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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 and start it up. This will trade welcome
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* banners, exchange keys, and setup crypto, compression, and MAC layers
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*/
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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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/* Enable all debugging when libssh2 was built with debugging enabled */
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libssh2_trace(session, ~0);
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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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rc = 1;
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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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/* check what authentication methods are available */
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userauthlist = libssh2_userauth_list(session, username,
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(unsigned int)strlen(username));
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if(userauthlist) {
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fprintf(stderr, "Authentication methods: %s\n", userauthlist);
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if(strstr(userauthlist, "password")) {
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auth_pw |= 1;
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}
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if(strstr(userauthlist, "keyboard-interactive")) {
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auth_pw |= 2;
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}
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if(strstr(userauthlist, "publickey")) {
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auth_pw |= 4;
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}
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/* check for options */
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if(argc > 4) {
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if((auth_pw & 1) && !strcmp(argv[4], "-p")) {
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auth_pw = 1;
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}
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if((auth_pw & 2) && !strcmp(argv[4], "-i")) {
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auth_pw = 2;
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}
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if((auth_pw & 4) && !strcmp(argv[4], "-k")) {
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auth_pw = 4;
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}
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}
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if(auth_pw & 1) {
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/* We could authenticate via password */
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if(libssh2_userauth_password(session, username, password)) {
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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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else {
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fprintf(stderr, "Authentication by password succeeded.\n");
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}
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}
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else if(auth_pw & 2) {
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/* Or via keyboard-interactive */
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if(libssh2_userauth_keyboard_interactive(session, username,
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&kbd_callback) ) {
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fprintf(stderr,
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"Authentication by keyboard-interactive failed.\n");
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goto shutdown;
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}
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else {
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fprintf(stderr,
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"Authentication by keyboard-interactive succeeded.\n");
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}
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}
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else if(auth_pw & 4) {
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/* Or by public key */
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size_t fn1sz, fn2sz;
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char *fn1, *fn2;
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char const *h = getenv("HOME");
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if(!h || !*h)
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h = ".";
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fn1sz = strlen(h) + strlen(pubkey) + 2;
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fn2sz = strlen(h) + strlen(privkey) + 2;
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fn1 = malloc(fn1sz);
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fn2 = malloc(fn2sz);
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if(!fn1 || !fn2) {
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free(fn2);
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free(fn1);
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fprintf(stderr, "out of memory\n");
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goto shutdown;
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}
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/* Avoid false positives */
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#if defined(__GNUC__) && __GNUC__ >= 7
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#pragma GCC diagnostic push
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#pragma GCC diagnostic warning "-Wformat-truncation=1"
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#endif
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/* Using asprintf() here would be much cleaner,
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but less portable */
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snprintf(fn1, fn1sz, "%s/%s", h, pubkey);
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snprintf(fn2, fn2sz, "%s/%s", h, privkey);
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#if defined(__GNUC__) && __GNUC__ >= 7
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#pragma GCC diagnostic pop
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#endif
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if(libssh2_userauth_publickey_fromfile(session, username,
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fn1, fn2,
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password)) {
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fprintf(stderr, "Authentication by public key failed.\n");
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free(fn2);
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free(fn1);
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goto shutdown;
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}
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else {
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fprintf(stderr, "Authentication by public key succeeded.\n");
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}
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free(fn2);
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free(fn1);
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}
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else {
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fprintf(stderr, "No supported authentication methods found.\n");
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goto shutdown;
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}
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}
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/* Request a session channel on which to run a shell */
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channel = libssh2_channel_open_session(session);
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if(!channel) {
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fprintf(stderr, "Unable to open a session\n");
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goto shutdown;
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}
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/* Some environment variables may be set,
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* It's up to the server which ones it'll allow though
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*/
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libssh2_channel_setenv(channel, "FOO", "bar");
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/* Request a terminal with 'vanilla' terminal emulation
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* See /etc/termcap for more options. This is useful when opening
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* an interactive shell.
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*/
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#if 0
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if(libssh2_channel_request_pty(channel, "vanilla")) {
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fprintf(stderr, "Failed requesting pty\n");
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}
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#endif
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if(argc > 5) {
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if(libssh2_channel_exec(channel, argv[5])) {
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fprintf(stderr, "Unable to request command on channel\n");
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goto shutdown;
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}
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/* Instead of just running a single command with libssh2_channel_exec,
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* a shell can be opened on the channel instead, for interactive use.
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* You usually want a pty allocated first in that case (see above). */
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#if 0
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if(libssh2_channel_shell(channel)) {
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fprintf(stderr, "Unable to request shell on allocated pty\n");
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goto shutdown;
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}
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#endif
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/* At this point the shell can be interacted with using
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* libssh2_channel_read()
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* libssh2_channel_read_stderr()
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* libssh2_channel_write()
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* libssh2_channel_write_stderr()
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*
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* Blocking mode may be (en|dis)abled with:
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* libssh2_channel_set_blocking()
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* If the server send EOF, libssh2_channel_eof() will return non-0
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* To send EOF to the server use: libssh2_channel_send_eof()
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* A channel can be closed with: libssh2_channel_close()
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* A channel can be freed with: libssh2_channel_free()
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*/
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/* Read and display all the data received on stdout (ignoring stderr)
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* until the channel closes. This will eventually block if the command
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* produces too much data on stderr; the loop must be rewritten to use
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* non-blocking mode and include interspersed calls to
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* libssh2_channel_read_stderr() to avoid this. See ssh2_echo.c for
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* an idea of how such a loop might look.
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*/
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while(!libssh2_channel_eof(channel)) {
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char buf[1024];
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ssize_t err = libssh2_channel_read(channel, buf, sizeof(buf));
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if(err < 0)
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fprintf(stderr, "Unable to read response: %ld\n", (long)err);
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else {
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fwrite(buf, 1, (size_t)err, stdout);
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}
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}
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}
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rc = libssh2_channel_get_exit_status(channel);
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if(libssh2_channel_close(channel))
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fprintf(stderr, "Unable to close channel\n");
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if(channel) {
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libssh2_channel_free(channel);
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channel = NULL;
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}
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/* Other channel types are supported via:
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* libssh2_scp_send64()
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* libssh2_scp_recv2()
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* libssh2_channel_direct_tcpip()
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*/
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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 rc;
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}
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