When I compile ssh_client code from example folder of libssh source directory( I have wrote about building process of this library in this link : libssh's functions couldn't be found on qt):
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <sys/time.h>
#ifdef HAVE_TERMIOS_H
#include <termios.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_PTY_H
#include <pty.h>
#endif
#include <sys/ioctl.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <libssh/callbacks.h>
#include <libssh/libssh.h>
#include <libssh/sftp.h>
#include "examples_common.h"
#define MAXCMD 10
static char *host = NULL;
static char *user = NULL;
static char *cmds[MAXCMD];
static char *config_file = NULL;
static struct termios terminal;
static char *pcap_file = NULL;
static char *proxycommand;
static int auth_callback(const char *prompt,
char *buf,
size_t len,
int echo,
int verify,
void *userdata)
{
(void) verify;
(void) userdata;
return ssh_getpass(prompt, buf, len, echo, verify);
}
struct ssh_callbacks_struct cb = {
.auth_function = auth_callback,
.userdata = NULL,
};
static void add_cmd(char *cmd)
{
int n;
for (n = 0; (n < MAXCMD) && cmds[n] != NULL; n++);
if (n == MAXCMD) {
return;
}
cmds[n] = strdup(cmd);
}
static void usage(void)
{
fprintf(stderr,
"Usage : ssh [options] [login@]hostname\n"
"sample client - libssh-%s\n"
"Options :\n"
" -l user : log in as user\n"
" -p port : connect to port\n"
" -d : use DSS to verify host public key\n"
" -r : use RSA to verify host public key\n"
" -F file : parse configuration file instead of default one\n"
#ifdef WITH_PCAP
" -P file : create a pcap debugging file\n"
#endif
#ifndef _WIN32
" -T proxycommand : command to execute as a socket proxy\n"
#endif
"\n",
ssh_version(0));
exit(0);
}
static int opts(int argc, char **argv)
{
int i;
while((i = getopt(argc,argv,"T:P:F:")) != -1) {
switch(i){
case 'P':
pcap_file = optarg;
break;
case 'F':
config_file = optarg;
break;
#ifndef _WIN32
case 'T':
proxycommand = optarg;
break;
#endif
default:
fprintf(stderr, "Unknown option %c\n", optopt);
usage();
}
}
if (optind < argc) {
host = argv[optind++];
}
while(optind < argc) {
add_cmd(argv[optind++]);
}
if (host == NULL) {
usage();
}
return 0;
}
#ifndef HAVE_CFMAKERAW
static void cfmakeraw(struct termios *termios_p)
{
termios_p->c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
termios_p->c_oflag &= ~OPOST;
termios_p->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
termios_p->c_cflag &= ~(CSIZE|PARENB);
termios_p->c_cflag |= CS8;
}
#endif
static void do_cleanup(int i)
{
/* unused variable */
(void) i;
tcsetattr(0, TCSANOW, &terminal);
}
static void do_exit(int i)
{
/* unused variable */
(void) i;
do_cleanup(0);
exit(0);
}
static ssh_channel chan;
static int signal_delayed = 0;
static void sigwindowchanged(int i)
{
(void) i;
signal_delayed = 1;
}
static void setsignal(void)
{
signal(SIGWINCH, sigwindowchanged);
signal_delayed = 0;
}
static void sizechanged(void)
{
struct winsize win = {
.ws_row = 0,
};
ioctl(1, TIOCGWINSZ, &win);
ssh_channel_change_pty_size(chan,win.ws_col, win.ws_row);
setsignal();
}
static void select_loop(ssh_session session,ssh_channel channel)
{
ssh_connector connector_in, connector_out, connector_err;
int rc;
ssh_event event = ssh_event_new();
/* stdin */
connector_in = ssh_connector_new(session);
ssh_connector_set_out_channel(connector_in, channel, SSH_CONNECTOR_STDINOUT);
ssh_connector_set_in_fd(connector_in, 0);
ssh_event_add_connector(event, connector_in);
/* stdout */
connector_out = ssh_connector_new(session);
ssh_connector_set_out_fd(connector_out, 1);
ssh_connector_set_in_channel(connector_out, channel, SSH_CONNECTOR_STDINOUT);
ssh_event_add_connector(event, connector_out);
/* stderr */
connector_err = ssh_connector_new(session);
ssh_connector_set_out_fd(connector_err, 2);
ssh_connector_set_in_channel(connector_err, channel, SSH_CONNECTOR_STDERR);
ssh_event_add_connector(event, connector_err);
while (ssh_channel_is_open(channel)) {
if (signal_delayed) {
sizechanged();
}
rc = ssh_event_dopoll(event, 60000);
if (rc == SSH_ERROR) {
fprintf(stderr, "Error in ssh_event_dopoll()\n");
break;
}
}
ssh_event_remove_connector(event, connector_in);
ssh_event_remove_connector(event, connector_out);
ssh_event_remove_connector(event, connector_err);
ssh_connector_free(connector_in);
ssh_connector_free(connector_out);
ssh_connector_free(connector_err);
ssh_event_free(event);
}
static void shell(ssh_session session)
{
ssh_channel channel;
struct termios terminal_local;
int interactive=isatty(0);
channel = ssh_channel_new(session);
if (channel == NULL) {
return;
}
if (interactive) {
tcgetattr(0, &terminal_local);
memcpy(&terminal, &terminal_local, sizeof(struct termios));
}
if (ssh_channel_open_session(channel)) {
printf("Error opening channel : %s\n", ssh_get_error(session));
ssh_channel_free(channel);
return;
}
chan = channel;
if (interactive) {
ssh_channel_request_pty(channel);
sizechanged();
}
if (ssh_channel_request_shell(channel)) {
printf("Requesting shell : %s\n", ssh_get_error(session));
ssh_channel_free(channel);
return;
}
if (interactive) {
cfmakeraw(&terminal_local);
tcsetattr(0, TCSANOW, &terminal_local);
setsignal();
}
signal(SIGTERM, do_cleanup);
select_loop(session, channel);
if (interactive) {
do_cleanup(0);
}
ssh_channel_free(channel);
}
static void batch_shell(ssh_session session)
{
ssh_channel channel;
char buffer[1024];
size_t i;
int s = 0;
for (i = 0; i < MAXCMD && cmds[i]; ++i) {
s += snprintf(buffer + s, sizeof(buffer) - s, "%s ", cmds[i]);
free(cmds[i]);
cmds[i] = NULL;
}
channel = ssh_channel_new(session);
if (channel == NULL) {
return;
}
ssh_channel_open_session(channel);
if (ssh_channel_request_exec(channel, buffer)) {
printf("Error executing '%s' : %s\n", buffer, ssh_get_error(session));
ssh_channel_free(channel);
return;
}
select_loop(session, channel);
ssh_channel_free(channel);
}
static int client(ssh_session session)
{
int auth = 0;
char *banner;
int state;
if (user) {
if (ssh_options_set(session, SSH_OPTIONS_USER, user) < 0) {
return -1;
}
}
if (ssh_options_set(session, SSH_OPTIONS_HOST, host) < 0) {
return -1;
}
if (proxycommand != NULL) {
if (ssh_options_set(session, SSH_OPTIONS_PROXYCOMMAND, proxycommand)) {
return -1;
}
}
/* Parse configuration file if specified: The command-line options will
* overwrite items loaded from configuration file */
if (config_file != NULL) {
ssh_options_parse_config(session, config_file);
} else {
ssh_options_parse_config(session, NULL);
}
if (ssh_connect(session)) {
fprintf(stderr, "Connection failed : %s\n", ssh_get_error(session));
return -1;
}
state = verify_knownhost(session);
if (state != 0) {
return -1;
}
ssh_userauth_none(session, NULL);
banner = ssh_get_issue_banner(session);
if (banner) {
printf("%s\n", banner);
free(banner);
}
auth = authenticate_console(session);
if (auth != SSH_AUTH_SUCCESS) {
return -1;
}
if (cmds[0] == NULL) {
shell(session);
} else {
batch_shell(session);
}
return 0;
}
static ssh_pcap_file pcap;
static void set_pcap(ssh_session session)
{
if (pcap_file == NULL) {
return;
}
pcap = ssh_pcap_file_new();
if (pcap == NULL) {
return;
}
if (ssh_pcap_file_open(pcap, pcap_file) == SSH_ERROR) {
printf("Error opening pcap file\n");
ssh_pcap_file_free(pcap);
pcap = NULL;
return;
}
ssh_set_pcap_file(session, pcap);
}
static void cleanup_pcap(void)
{
if (pcap != NULL) {
ssh_pcap_file_free(pcap);
}
pcap = NULL;
}
int main(int argc, char **argv)
{
ssh_session session;
session = ssh_new();
ssh_callbacks_init(&cb);
ssh_set_callbacks(session,&cb);
if (ssh_options_getopt(session, &argc, argv)) {
fprintf(stderr,
"Error parsing command line: %s\n",
ssh_get_error(session));
usage();
}
opts(argc, argv);
signal(SIGTERM, do_exit);
set_pcap(session);
client(session);
ssh_disconnect(session);
ssh_free(session);
cleanup_pcap();
ssh_finalize();
return 0;
}
I got the following error:
/home/heydari.f/projects/ssh_client/ssh_client/main.c:100: error: config.h: No such file or directory
#include "config.h"
^~~~~~~~~~
Is there anything to do with configure or what? I use Qt and my os is ubuntu 18.04.
Config headers as config.h normally aren't needed to compile a program against a library. Those are generated to compile the library, not the programs that link against them. If not, there will be lot of trouble as lots of software use them and there would be lots of collisions between them.
Being an example, it may be that it uses the config.h, but in that case I'm pretty sure you should compile with the system libssh uses to compile. (You may need to specify an option to compile examples when calling configure or specify something in DefineOptions.cmake or something in the same line.)
If you copied the sources (as it seems as the error states projects/ssh_client/) to build with Qt, you probably can remove that include unless it is a config from Qt itself.
Also, if you are compiling with Qt you surely need to install the lib and follow @Dmitry advice about -I, -L and -l flags to compiler.