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1 | // Mosh: the mobile shell |
2 | // Copyright 2012 Keith Winstein | |
3 | // | |
4 | // This program is free software: you can redistribute it and/or modify | |
5 | // it under the terms of the GNU General Public License as published by | |
6 | // the Free Software Foundation, either version 3 of the License, or | |
7 | // (at your option) any later version. | |
8 | // | |
9 | // This program is distributed in the hope that it will be useful, | |
10 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | // GNU General Public License for more details. | |
13 | // | |
14 | // You should have received a copy of the GNU General Public License | |
15 | // along with this program. If not, see <http://www.gnu.org/licenses/>. | |
16 | ||
17 | #include <limits.h> | |
18 | #include <unistd.h> | |
19 | #include <stdlib.h> | |
20 | #include <stdarg.h> | |
21 | #include <string.h> | |
22 | #include <vector> | |
23 | #include <map> | |
24 | #include <stdio.h> | |
25 | #include <string> | |
26 | #include <sys/socket.h> | |
27 | #include <getopt.h> | |
28 | #include <arpa/inet.h> | |
29 | #include <netdb.h> | |
30 | #include <signal.h> | |
31 | #include <errno.h> | |
32 | #include <sys/ioctl.h> | |
33 | #include <sys/types.h> | |
34 | #include <sys/wait.h> | |
35 | #include <termios.h> | |
36 | #include <pty.h> | |
37 | ||
38 | using namespace std; | |
39 | ||
40 | inline string shell_quote_string( const string &x ) | |
41 | { | |
42 | string result = "'"; | |
43 | string rest = x; | |
44 | while ( rest.size() ) { | |
45 | size_t good_part = rest.find( "'" ); | |
46 | result += rest.substr( 0, good_part ); | |
47 | if ( good_part != string::npos ) { | |
48 | result += "'\\''"; | |
49 | rest = rest.substr( good_part + 1 ); | |
50 | } else { | |
51 | break; | |
52 | } | |
53 | } | |
54 | return result + "'"; | |
55 | } | |
56 | ||
57 | template <typename SequenceT> | |
58 | inline string shell_quote( const SequenceT &sequence ) | |
59 | { | |
60 | string result; | |
61 | for ( typename SequenceT::const_iterator i = sequence.begin(); | |
62 | i != sequence.end(); | |
63 | i++ ) { | |
64 | result += shell_quote_string( *i ) + " "; | |
65 | } | |
66 | return result.substr( 0, result.size() - 1 ); | |
67 | } | |
68 | ||
69 | void die( const char *format, ... ) { | |
70 | va_list args; | |
71 | va_start( args, format ); | |
72 | vfprintf( stderr, format, args ); | |
73 | va_end( args ); | |
74 | fprintf( stderr, "\n" ); | |
75 | exit( 255 ); | |
76 | } | |
77 | ||
78 | static const char *usage_format = | |
79 | "Usage: %s [options] [--] [user@]host [command...]\n" | |
80 | " --client=PATH mosh client on local machine\n" | |
81 | " (default: \"mosh-client\")\n" | |
82 | " --server=COMMAND mosh server on remote machine\n" | |
83 | " (default: \"mosh-server\")\n" | |
84 | "\n" | |
85 | " --predict=adaptive local echo for slower links [default]\n" | |
86 | "-a --predict=always use local echo even on fast links\n" | |
87 | "-n --predict=never never use local echo\n" | |
88 | "\n" | |
89 | "-p NUM --port=NUM server-side UDP port\n" | |
90 | "\n" | |
91 | "-P NUM --ssh-port=NUM ssh server port\n" | |
92 | " (default: let the ssh command choose)\n" | |
93 | "\n" | |
94 | " --ssh=COMMAND ssh command to run when setting up session\n" | |
95 | " (example: \"ssh -p 2222\")\n" | |
96 | " (default: \"ssh\")\n" | |
97 | "\n" | |
98 | " --help this message\n" | |
99 | " --version version and copyright information\n" | |
100 | "\n" | |
101 | "Please report bugs to mosh-devel@mit.edu.\n" | |
102 | "Mosh home page: http://mosh.mit.edu"; | |
103 | ||
104 | static const char *version_format = | |
105 | "mosh %s\n" | |
106 | "Copyright 2012 Keith Winstein <mosh-devel@mit.edu>\n" | |
107 | "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n" | |
108 | "This is free software: you are free to change and redistribute it.\n" | |
109 | "There is NO WARRANTY, to the extent permitted by law."; | |
110 | ||
111 | static const char *key_valid_char_set = | |
112 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789/+"; | |
113 | ||
114 | static char *argv0; | |
115 | ||
116 | void predict_check( const string &predict, bool env_set ) | |
117 | { | |
118 | if ( predict != "adaptive" && | |
119 | predict != "always" && | |
120 | predict != "never" ) { | |
121 | fprintf( stderr, "%s: Unknown mode \"%s\"%s.\n", argv0, predict.c_str(), | |
122 | env_set ? " (MOSH_PREDICTION_DISPLAY in environment)" : "" ); | |
123 | die( usage_format, argv0 ); | |
124 | } | |
125 | } | |
126 | ||
127 | void cat( int ifd, int ofd ) | |
128 | { | |
129 | char buf[4096]; | |
130 | ssize_t n; | |
131 | while ( 1 ) { | |
132 | n = read( ifd, buf, sizeof( buf ) ); | |
133 | if ( n==-1 ) { | |
134 | if (errno == EINTR ) { | |
135 | continue; | |
136 | } | |
137 | break; | |
138 | } | |
139 | if ( n==0 ) { | |
140 | break; | |
141 | } | |
142 | n = write( ofd, buf, n ); | |
143 | if ( n==-1 ) { | |
144 | break; | |
145 | } | |
146 | } | |
147 | } | |
148 | ||
149 | bool valid_port(string port) { | |
150 | if ( port.size() ) { | |
151 | return port.find_first_not_of( "0123456789" ) == string::npos && | |
152 | atoi( port.c_str() ) > 0 && | |
153 | atoi( port.c_str() ) <= 65535; | |
154 | } | |
155 | return true; // consider no port to be the default value | |
156 | } | |
157 | ||
158 | int main( int argc, char *argv[] ) | |
159 | { | |
160 | argv0 = argv[0]; | |
161 | string client = "mosh-client"; | |
162 | string server = "mosh-server"; | |
163 | string ssh = "ssh"; | |
164 | string predict, port_request, ssh_port; | |
165 | int help=0, version=0, fake_proxy=0; | |
166 | ||
167 | static struct option long_options[] = | |
168 | { | |
169 | { "client", required_argument, 0, 'c' }, | |
170 | { "server", required_argument, 0, 's' }, | |
171 | { "predict", required_argument, 0, 'r' }, | |
172 | { "port", required_argument, 0, 'p' }, | |
173 | { "ssh-port", required_argument, 0, 'P' }, | |
174 | { "ssh", required_argument, 0, 'S' }, | |
175 | { "help", no_argument, &help, 1 }, | |
176 | { "version", no_argument, &version, 1 }, | |
177 | { "fake-proxy!", no_argument, &fake_proxy, 1 }, | |
178 | { 0, 0, 0, 0 } | |
179 | }; | |
180 | while ( 1 ) { | |
181 | int option_index = 0; | |
182 | int c = getopt_long( argc, argv, "anp:P:", | |
183 | long_options, &option_index ); | |
184 | if ( c == -1 ) { | |
185 | break; | |
186 | } | |
187 | ||
188 | switch ( c ) { | |
189 | case 0: | |
190 | // flag has been set | |
191 | break; | |
192 | case 'c': | |
193 | client = optarg; | |
194 | break; | |
195 | case 's': | |
196 | server = optarg; | |
197 | break; | |
198 | case 'r': | |
199 | predict = optarg; | |
200 | break; | |
201 | case 'p': | |
202 | port_request = optarg; | |
203 | break; | |
204 | case 'P': | |
205 | ssh_port = optarg; | |
206 | break; | |
207 | case 'S': | |
208 | ssh = optarg; | |
209 | break; | |
210 | case 'a': | |
211 | predict = "always"; | |
212 | break; | |
213 | case 'n': | |
214 | predict = "never"; | |
215 | break; | |
216 | default: | |
217 | die( usage_format, argv[0] ); | |
218 | } | |
219 | } | |
220 | ||
221 | if ( help ) { | |
222 | die( usage_format, argv[0] ); | |
223 | } | |
224 | if ( version ) { | |
225 | die( version_format, PACKAGE_VERSION ); | |
226 | } | |
227 | ||
228 | if ( predict.size() ) { | |
229 | predict_check( predict, 0 ); | |
230 | } else if ( getenv( "MOSH_PREDICTION_DELAY" ) ) { | |
231 | predict = getenv( "MOSH_PREDICTION_DELAY" ); | |
232 | predict_check( predict, 1 ); | |
233 | } else { | |
234 | predict = "adaptive"; | |
235 | predict_check( predict, 0 ); | |
236 | } | |
237 | ||
238 | if(!valid_port(port_request)) { | |
239 | die( "%s: Server-side port (%s) must be within valid range [0..65535].", | |
240 | argv[0], | |
241 | port_request.c_str() ); | |
242 | } | |
243 | ||
244 | if(!valid_port(ssh_port)) { | |
245 | die( "%s: SSH port (%s) must be within valid range [0..65535].", | |
246 | argv[0], | |
247 | ssh_port.c_str() ); | |
248 | } | |
249 | ||
250 | unsetenv( "MOSH_PREDICTION_DISPLAY" ); | |
251 | ||
252 | if ( fake_proxy ) { | |
253 | string host = argv[optind++]; | |
254 | string port = argv[optind++]; | |
255 | ||
256 | int sockfd = -1; | |
257 | struct addrinfo hints, *servinfo, *p; | |
258 | int rv; | |
259 | ||
260 | memset( &hints, 0, sizeof( hints ) ); | |
261 | hints.ai_socktype = SOCK_STREAM; | |
262 | ||
263 | if ( ( rv = getaddrinfo( host.c_str(), | |
264 | port.c_str(), | |
265 | &hints, | |
266 | &servinfo ) ) != 0 ) { | |
267 | die( "%s: Could not resolve hostname %s: getaddrinfo: %s", | |
268 | argv[0], | |
269 | host.c_str(), | |
270 | gai_strerror( rv ) ); | |
271 | } | |
272 | ||
273 | int try_family = AF_INET; | |
274 | // loop through all the results and connect to the first we can | |
275 | for ( p = servinfo; p != NULL || try_family == AF_INET; p = p->ai_next ) { | |
276 | if(p == NULL && try_family == AF_INET) { // start over and try AF_INET6 | |
277 | p = servinfo; | |
278 | try_family = AF_INET6; | |
279 | } | |
280 | if(p == NULL) { | |
281 | break; // servinfo == NULL | |
282 | } | |
283 | ||
284 | if(p->ai_family != try_family) { | |
285 | continue; | |
286 | } | |
287 | ||
288 | if ( ( sockfd = socket( p->ai_family, SOCK_STREAM, IPPROTO_TCP ) ) == -1 ) { | |
289 | continue; | |
290 | } | |
291 | ||
292 | if ( connect( sockfd, p->ai_addr, p->ai_addrlen ) == -1 ) { | |
293 | close( sockfd ); | |
294 | continue; | |
295 | } | |
296 | ||
297 | char host[NI_MAXHOST], service[NI_MAXSERV]; | |
298 | if ( getnameinfo( p->ai_addr, p->ai_addrlen, | |
299 | host, NI_MAXHOST, | |
300 | service, NI_MAXSERV, | |
301 | NI_NUMERICSERV | NI_NUMERICHOST ) == -1 ) { | |
302 | die( "Couldn't get host name info" ); | |
303 | } | |
304 | ||
305 | fprintf( stderr, "MOSH IP %s\n", host ); | |
306 | break; // if we get here, we must have connected successfully | |
307 | } | |
308 | ||
309 | if ( p == NULL ) { | |
310 | // looped off the end of the list with no connection | |
311 | die( "%s: failed to connect to host %s port %s", | |
312 | argv[0], host.c_str(), port.c_str() ); | |
313 | } | |
314 | ||
315 | freeaddrinfo( servinfo ); // all done with this structure | |
316 | ||
317 | int pid = fork(); | |
1f87518b | 318 | if ( pid == -1 ) die( "%s: fork: %d", argv[0], errno ); |
188d1201 | 319 | if ( pid == 0 ) { |
3afa4f34 FF |
320 | close( STDIN_FILENO ); |
321 | cat( sockfd, STDOUT_FILENO ); | |
188d1201 FF |
322 | shutdown( sockfd, 0 ); |
323 | exit( 0 ); | |
324 | } | |
325 | signal( SIGHUP, SIG_IGN ); | |
3afa4f34 FF |
326 | close( STDOUT_FILENO ); |
327 | cat( STDIN_FILENO, sockfd ); | |
328 | shutdown( sockfd, SHUT_WR /* = 1 */ ); | |
329 | close( STDIN_FILENO ); | |
188d1201 FF |
330 | waitpid( pid, NULL, 0 ); |
331 | exit( 0 ); | |
332 | } | |
333 | ||
334 | if ( argc - optind < 1 ) { | |
335 | die( usage_format, argv[0] ); | |
336 | } | |
337 | ||
338 | string userhost = argv[optind++]; | |
339 | char **command = &argv[optind]; | |
340 | int commands = argc - optind; | |
341 | ||
342 | string color_invocation = client + " -c"; | |
343 | FILE *color_file = popen( color_invocation.c_str(), "r" ); | |
1f87518b | 344 | if ( !color_file ) die( "%s: popen: %d", argv[0], errno ); |
188d1201 FF |
345 | char *buf = NULL; |
346 | size_t buf_sz = 0; | |
347 | ssize_t n; | |
348 | if ( ( n = getline( &buf, &buf_sz, color_file ) ) < 0 ) { | |
349 | die( "%s: Can't count colors: %d", argv[0], errno ); | |
350 | } | |
1f87518b FF |
351 | // Chomp the trailing newline: |
352 | if ( n > 0 && buf[n - 1] == '\n' ) n--; | |
188d1201 FF |
353 | string colors = string( buf, n ); |
354 | pclose( color_file ); | |
355 | ||
356 | if ( !colors.size() || | |
357 | colors.find_first_not_of( "0123456789" ) != string::npos || | |
358 | atoi( colors.c_str() ) < 0 ) { | |
359 | colors = "0"; | |
360 | } | |
361 | ||
362 | int pty, pty_slave; | |
363 | struct winsize ws; | |
364 | if ( ioctl( 0, TIOCGWINSZ, &ws ) == -1 ) { | |
365 | die( "%s: ioctl: %d", argv[0], errno ); | |
366 | } | |
367 | ||
368 | if ( openpty( &pty, &pty_slave, NULL, NULL, &ws ) == -1 ) { | |
369 | die( "%s: openpty: %d", argv[0], errno ); | |
370 | } | |
371 | ||
372 | int pid = fork(); | |
3afa4f34 | 373 | if ( pid == -1 ) die( "%s: fork: %d", argv[0], errno ); |
188d1201 FF |
374 | if ( pid == 0 ) { |
375 | close( pty ); | |
376 | if ( -1 == dup2( pty_slave, 1 ) || | |
377 | -1 == dup2( pty_slave, 2 ) ) { | |
378 | die( "%s: dup2: %d", argv[0], errno ); | |
379 | } | |
380 | close( pty_slave ); | |
381 | ||
382 | vector<string> server_args; | |
383 | server_args.push_back( "new" ); | |
384 | server_args.push_back( "-s" ); | |
385 | server_args.push_back( "-c" ); | |
386 | server_args.push_back( colors ); | |
387 | if ( port_request.size() ) { | |
388 | server_args.push_back( "-p" ); | |
389 | server_args.push_back( port_request ); | |
390 | } | |
32144b83 FF |
391 | |
392 | for (char const* env_name : { | |
393 | "LANG", "LANGUAGE", "LC_CTYPE", "LC_NUMERIC", | |
394 | "LC_TIME", "LC_COLLATE", "LC_MONETARY", "LC_MESSAGES", "LC_PAPER", | |
395 | "LC_NAME", "LC_ADDRESS", "LC_TELEPHONE", "LC_MEASUREMENT", | |
396 | "LC_IDENTIFICATION", "LC_ALL" }) { | |
397 | char* env_value = getenv(env_name); | |
398 | if (env_value) { | |
399 | server_args.push_back("-l"); | |
400 | server_args.push_back(string(env_name) + "=" + env_value); | |
401 | } | |
402 | } | |
403 | ||
188d1201 FF |
404 | if ( commands ) { |
405 | server_args.insert( server_args.end(), command, command + commands ); | |
406 | } | |
407 | string quoted_self = shell_quote_string( string( argv[0] ) ); | |
408 | string quoted_server_args = shell_quote( server_args ); | |
409 | fflush( stdout ); | |
410 | ||
411 | string proxy_arg = "ProxyCommand=" + quoted_self + " --fake-proxy -- %h %p"; | |
412 | string ssh_remote_command = server + " " + quoted_server_args; | |
413 | ||
414 | vector<string> ssh_args; | |
415 | ssh_args.push_back( "-S" ); | |
416 | ssh_args.push_back( "none" ); | |
417 | ssh_args.push_back( "-o" ); | |
418 | ssh_args.push_back( proxy_arg ); | |
419 | ssh_args.push_back( "-t" ); | |
420 | ssh_args.push_back( userhost ); | |
421 | if ( ssh_port.size() ) { | |
422 | ssh_args.push_back( "-p" ); | |
423 | ssh_args.push_back( ssh_port ); | |
424 | } | |
425 | ssh_args.push_back( "--" ); | |
426 | ssh_args.push_back( ssh_remote_command ); | |
427 | ||
428 | string ssh_exec_string = ssh + " " + shell_quote( ssh_args ); | |
429 | ||
430 | int ret = execlp( "sh", "sh", "-c", ssh_exec_string.c_str(), (char *)NULL ); | |
431 | if ( ret == -1 ) { | |
432 | die( "Cannot exec ssh: %d", errno ); | |
433 | } | |
434 | } | |
435 | ||
436 | close( pty_slave ); | |
437 | string ip, port, key; | |
438 | ||
439 | FILE *pty_file = fdopen( pty, "r" ); | |
440 | string line; | |
441 | while ( ( n = getline( &buf, &buf_sz, pty_file ) ) >= 0 ) { | |
442 | line = string( buf, n ); | |
443 | line = line.erase( line.find_last_not_of( "\n" ) ); | |
444 | if ( line.compare( 0, 8, "MOSH IP " ) == 0 ) { | |
445 | size_t ip_end = line.find_last_not_of( " \t\n\r" ); | |
446 | if ( ip_end != string::npos && ip_end >= 8 ) { | |
447 | ip = line.substr( 8, ip_end + 1 - 8 ); | |
448 | } | |
449 | } else if ( line.compare( 0, 13, "MOSH CONNECT " ) == 0 ) { | |
450 | size_t port_end = line.find_first_not_of( "0123456789", 13 ); | |
451 | if ( port_end != string::npos && port_end >= 13 ) { | |
452 | port = line.substr( 13, port_end - 13 ); | |
453 | } | |
454 | string rest = line.substr( port_end + 1 ); | |
455 | size_t key_end = rest.find_last_not_of( " \t\n\r" ); | |
456 | size_t key_valid_end = rest.find_last_of( key_valid_char_set ); | |
457 | if ( key_valid_end == key_end && key_end + 1 == 22 ) { | |
458 | key = rest.substr( 0, key_end + 1 ); | |
459 | } | |
460 | break; | |
461 | } else { | |
462 | printf( "%s\n", line.c_str() ); | |
463 | } | |
464 | } | |
465 | waitpid( pid, NULL, 0 ); | |
466 | ||
467 | if ( !ip.size() ) { | |
468 | die( "%s: Did not find remote IP address (is SSH ProxyCommand disabled?).", | |
469 | argv[0] ); | |
470 | } | |
471 | ||
472 | if ( !key.size() || !port.size() ) { | |
473 | die( "%s: Did not find mosh server startup message.", argv[0] ); | |
474 | } | |
475 | ||
476 | setenv( "MOSH_KEY", key.c_str(), 1 ); | |
477 | setenv( "MOSH_PREDICTION_DISPLAY", predict.c_str(), 1 ); | |
478 | execlp( client.c_str(), client.c_str(), ip.c_str(), port.c_str(), (char *)NULL ); | |
479 | } |