aboutsummaryrefslogtreecommitdiff
path: root/examples/sample.c
blob: d9c6dde6abd9b49def8fb3e2295fe9b8e2e40d1e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
/* client.c */
/*
Copyright 2003-2009 Aris Adamantiadis

This file is part of the SSH Library

You are free to copy this file, modify it in any way, consider it being public
domain. This does not apply to the rest of the library though, but it is
allowed to cut-and-paste working code from this file to any license of
program.
The goal is to show the API in action. It's not a reference on how terminal
clients must be made or how a client should react.
*/

#include "config.h"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>

#include <sys/select.h>
#include <sys/time.h>
#ifdef HAVE_PTY_H
#include <pty.h>
#endif
#include <sys/ioctl.h>
#include <signal.h>
#include <errno.h>
#include <libssh/callbacks.h>
#include <libssh/libssh.h>
#include <libssh/sftp.h>

#include <fcntl.h>

#include "examples_common.h"
#define MAXCMD 10
char *host;
char *user;
char *cmds[MAXCMD];
struct termios terminal;

static int auth_callback(const char *prompt, char *buf, size_t len,
    int echo, int verify, void *userdata) {
  char *answer = NULL;
  char *ptr;

  (void) verify;
  (void) userdata;

  if (echo) {
    while ((answer = fgets(buf, len, stdin)) == NULL);
    if ((ptr = strchr(buf, '\n'))) {
      ptr = '\0';
    }
  } else {
    answer = getpass(prompt);
  }

  if (answer == NULL) {
    return -1;
  }

  strncpy(buf, answer, len);

  return 0;
}

struct ssh_callbacks_struct cb = {
		.auth_function=auth_callback,
		.userdata=NULL
};

static void add_cmd(char *cmd){
    int n;
    for(n=0;cmds[n] && (n<MAXCMD);n++);
    if(n==MAXCMD)
        return;
    cmds[n]=strdup(cmd);
}

static void usage(){
    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",
    ssh_version(0));
    exit(0);
}

static int opts(int argc, char **argv){
    int i;

//    for(i=0;i<argc;i++)
//        printf("%d : %s\n",i,argv[i]);
    /* insert your own arguments here */
    while((i=getopt(argc,argv,""))!=-1){
        switch(i){
            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);
}

ssh_channel chan;
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 = { 0, 0, 0, 0 };
    ioctl(1, TIOCGWINSZ, &win);
    channel_change_pty_size(chan,win.ws_col, win.ws_row);
//    printf("Changed pty size\n");
    setsignal();
}
static void select_loop(ssh_session session,ssh_channel channel){
    fd_set fds;
    struct timeval timeout;
    char buffer[4096];
    ssh_buffer readbuf=buffer_new();
    ssh_channel channels[2];
    int lus;
    int eof=0;
    int maxfd;
    int ret;
    while(channel){
       /* when a signal is caught, ssh_select will return
         * with SSH_EINTR, which means it should be started
         * again. It lets you handle the signal the faster you
         * can, like in this window changed example. Of course, if
         * your signal handler doesn't call libssh at all, you're
         * free to handle signals directly in sighandler.
         */
        do{
            FD_ZERO(&fds);
            if(!eof)
                FD_SET(0,&fds);
            timeout.tv_sec=30;
            timeout.tv_usec=0;
            FD_SET(ssh_get_fd(session),&fds);
            maxfd=ssh_get_fd(session)+1;
            ret=select(maxfd,&fds,NULL,NULL,&timeout);
            if(ret==EINTR)
                continue;
            if(FD_ISSET(0,&fds)){
                lus=read(0,buffer,sizeof(buffer));
                if(lus)
                    channel_write(channel,buffer,lus);
                else {
                    eof=1;
                    channel_send_eof(channel);
                }
            }
            if(FD_ISSET(ssh_get_fd(session),&fds)){
                ssh_set_fd_toread(session);
            }
            channels[0]=channel; // set the first channel we want to read from
            channels[1]=NULL;
            ret=channel_select(channels,NULL,NULL,NULL); // no specific timeout - just poll
            if(signal_delayed)
                sizechanged();
        } while (ret==EINTR || ret==SSH_EINTR);

        // we already looked for input from stdin. Now, we are looking for input from the channel

        if(channel && channel_is_closed(channel)){
            ssh_log(session,SSH_LOG_RARE,"exit-status : %d\n",channel_get_exit_status(channel));

            channel_free(channel);
            channel=NULL;
            channels[0]=NULL;
        }
        if(channels[0]){
            while(channel && channel_is_open(channel) && channel_poll(channel,0)){
                lus=channel_read_buffer(channel,readbuf,0,0);
                if(lus==-1){
                    fprintf(stderr, "Error reading channel: %s\n",
                        ssh_get_error(session));
                    return;
                }
                if(lus==0){
                    ssh_log(session,SSH_LOG_RARE,"EOF received\n");
                    ssh_log(session,SSH_LOG_RARE,"exit-status : %d\n",channel_get_exit_status(channel));

                    channel_free(channel);
                    channel=channels[0]=NULL;
                } else
                    write(1,buffer_get(readbuf),lus);
            }
            while(channel && channel_is_open(channel) && channel_poll(channel,1)){ /* stderr */
                lus=channel_read_buffer(channel,readbuf,0,1);
                if(lus==-1){
                    fprintf(stderr, "Error reading channel: %s\n",
                        ssh_get_error(session));
                    return;
                }
                if(lus==0){
                    ssh_log(session,SSH_LOG_RARE,"EOF received\n");
                    ssh_log(session,SSH_LOG_RARE,"exit-status : %d\n",channel_get_exit_status(channel));
                    channel_free(channel);
                    channel=channels[0]=NULL;
                } else
                    write(2,buffer_get(readbuf),lus);
            }
        }
        if(channel && channel_is_closed(channel)){
            channel_free(channel);
            channel=NULL;
        }
    }
    buffer_free(readbuf);
}


static void shell(ssh_session session){
    ssh_channel channel;
    struct termios terminal_local;
    int interactive=isatty(0);
    channel = channel_new(session);
    if(interactive){
        tcgetattr(0,&terminal_local);
        memcpy(&terminal,&terminal_local,sizeof(struct termios));
    }
    if(channel_open_session(channel)){
        printf("error opening channel : %s\n",ssh_get_error(session));
        return;
    }
    chan=channel;
    if(interactive){
        channel_request_pty(channel);
        sizechanged();
    }
    if(channel_request_shell(channel)){
        printf("Requesting shell : %s\n",ssh_get_error(session));
        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);
}

static void batch_shell(ssh_session session){
    ssh_channel channel;
    char buffer[1024];
    int i,s=0;
    for(i=0;i<MAXCMD && cmds[i];++i)
        s+=snprintf(buffer+s,sizeof(buffer)-s,"%s ",cmds[i]);
    channel=channel_new(session);
    channel_open_session(channel);
    if(channel_request_exec(channel,buffer)){
        printf("error executing \"%s\" : %s\n",buffer,ssh_get_error(session));
        return;
    }
    select_loop(session,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;

  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;
  }
  ssh_log(session, SSH_LOG_FUNCTIONS, "Authentication success");
  if(!cmds[0])
  	shell(session);
  else
  	batch_shell(session);
  return 0;
}

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);

    client(session);
    ssh_disconnect(session);
    ssh_free(session);
    ssh_finalize();

    return 0;
}