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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * Created: Sun Sep 10 00:30:37 1995 ylo | |
6 | * Server main loop for handling the interactive session. | |
7 | */ | |
e78a59f5 | 8 | /* |
9 | * SSH2 support by Markus Friedl. | |
10 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
11 | */ | |
8efc0c15 | 12 | |
13 | #include "includes.h" | |
14 | #include "xmalloc.h" | |
15 | #include "ssh.h" | |
16 | #include "packet.h" | |
17 | #include "buffer.h" | |
18 | #include "servconf.h" | |
19 | #include "pty.h" | |
7368a6c8 | 20 | #include "channels.h" |
21 | ||
22 | #include "compat.h" | |
e78a59f5 | 23 | #include "ssh2.h" |
24 | #include "session.h" | |
7368a6c8 | 25 | #include "dispatch.h" |
8efc0c15 | 26 | |
27 | static Buffer stdin_buffer; /* Buffer for stdin data. */ | |
28 | static Buffer stdout_buffer; /* Buffer for stdout data. */ | |
29 | static Buffer stderr_buffer; /* Buffer for stderr data. */ | |
30 | static int fdin; /* Descriptor for stdin (for writing) */ | |
31 | static int fdout; /* Descriptor for stdout (for reading); | |
32 | May be same number as fdin. */ | |
33 | static int fderr; /* Descriptor for stderr. May be -1. */ | |
34 | static long stdin_bytes = 0; /* Number of bytes written to stdin. */ | |
35 | static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */ | |
36 | static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */ | |
37 | static long fdout_bytes = 0; /* Number of stdout bytes read from program. */ | |
38 | static int stdin_eof = 0; /* EOF message received from client. */ | |
39 | static int fdout_eof = 0; /* EOF encountered reading from fdout. */ | |
40 | static int fderr_eof = 0; /* EOF encountered readung from fderr. */ | |
41 | static int connection_in; /* Connection to client (input). */ | |
42 | static int connection_out; /* Connection to client (output). */ | |
43 | static unsigned int buffer_high;/* "Soft" max buffer size. */ | |
44 | static int max_fd; /* Max file descriptor number for select(). */ | |
45 | ||
aa3378df | 46 | /* |
47 | * This SIGCHLD kludge is used to detect when the child exits. The server | |
48 | * will exit after that, as soon as forwarded connections have terminated. | |
691a8a9f | 49 | * |
50 | * After SIGCHLD child_has_selected is set to 1 after the first pass | |
51 | * through the wait_until_can_do_something() select(). This ensures | |
52 | * that the child's output gets a chance to drain before it is yanked. | |
aa3378df | 53 | */ |
8efc0c15 | 54 | |
9da5c3c9 | 55 | static pid_t child_pid; /* Pid of the child. */ |
8efc0c15 | 56 | static volatile int child_terminated; /* The child has terminated. */ |
691a8a9f | 57 | static volatile int child_has_selected; /* Child has had chance to drain. */ |
8efc0c15 | 58 | static volatile int child_wait_status; /* Status from wait(). */ |
59 | ||
7368a6c8 | 60 | void server_init_dispatch(void); |
61 | ||
6ae2364d | 62 | void |
5260325f | 63 | sigchld_handler(int sig) |
8efc0c15 | 64 | { |
5260325f | 65 | int save_errno = errno; |
9da5c3c9 | 66 | pid_t wait_pid; |
67 | ||
5260325f | 68 | debug("Received SIGCHLD."); |
69 | wait_pid = wait((int *) &child_wait_status); | |
70 | if (wait_pid != -1) { | |
71 | if (wait_pid != child_pid) | |
72 | error("Strange, got SIGCHLD and wait returned pid %d but child is %d", | |
73 | wait_pid, child_pid); | |
74 | if (WIFEXITED(child_wait_status) || | |
75 | WIFSIGNALED(child_wait_status)) | |
76 | child_terminated = 1; | |
691a8a9f | 77 | child_has_selected = 0; |
5260325f | 78 | } |
79 | signal(SIGCHLD, sigchld_handler); | |
80 | errno = save_errno; | |
8efc0c15 | 81 | } |
6ae2364d | 82 | void |
e78a59f5 | 83 | sigchld_handler2(int sig) |
84 | { | |
85 | int save_errno = errno; | |
86 | debug("Received SIGCHLD."); | |
87 | child_terminated = 1; | |
e78a59f5 | 88 | errno = save_errno; |
89 | } | |
8efc0c15 | 90 | |
5260325f | 91 | /* |
92 | * Make packets from buffered stderr data, and buffer it for sending | |
93 | * to the client. | |
94 | */ | |
6ae2364d | 95 | void |
5260325f | 96 | make_packets_from_stderr_data() |
8efc0c15 | 97 | { |
5260325f | 98 | int len; |
99 | ||
100 | /* Send buffered stderr data to the client. */ | |
101 | while (buffer_len(&stderr_buffer) > 0 && | |
a408af76 | 102 | packet_not_very_much_data_to_write()) { |
5260325f | 103 | len = buffer_len(&stderr_buffer); |
104 | if (packet_is_interactive()) { | |
105 | if (len > 512) | |
106 | len = 512; | |
107 | } else { | |
108 | /* Keep the packets at reasonable size. */ | |
109 | if (len > packet_get_maxsize()) | |
110 | len = packet_get_maxsize(); | |
111 | } | |
112 | packet_start(SSH_SMSG_STDERR_DATA); | |
113 | packet_put_string(buffer_ptr(&stderr_buffer), len); | |
114 | packet_send(); | |
115 | buffer_consume(&stderr_buffer, len); | |
116 | stderr_bytes += len; | |
8efc0c15 | 117 | } |
8efc0c15 | 118 | } |
119 | ||
5260325f | 120 | /* |
121 | * Make packets from buffered stdout data, and buffer it for sending to the | |
122 | * client. | |
123 | */ | |
6ae2364d | 124 | void |
5260325f | 125 | make_packets_from_stdout_data() |
8efc0c15 | 126 | { |
5260325f | 127 | int len; |
128 | ||
129 | /* Send buffered stdout data to the client. */ | |
130 | while (buffer_len(&stdout_buffer) > 0 && | |
a408af76 | 131 | packet_not_very_much_data_to_write()) { |
5260325f | 132 | len = buffer_len(&stdout_buffer); |
133 | if (packet_is_interactive()) { | |
134 | if (len > 512) | |
135 | len = 512; | |
136 | } else { | |
137 | /* Keep the packets at reasonable size. */ | |
138 | if (len > packet_get_maxsize()) | |
139 | len = packet_get_maxsize(); | |
140 | } | |
141 | packet_start(SSH_SMSG_STDOUT_DATA); | |
142 | packet_put_string(buffer_ptr(&stdout_buffer), len); | |
143 | packet_send(); | |
144 | buffer_consume(&stdout_buffer, len); | |
145 | stdout_bytes += len; | |
8efc0c15 | 146 | } |
8efc0c15 | 147 | } |
148 | ||
5260325f | 149 | /* |
150 | * Sleep in select() until we can do something. This will initialize the | |
151 | * select masks. Upon return, the masks will indicate which descriptors | |
152 | * have data or can accept data. Optionally, a maximum time can be specified | |
153 | * for the duration of the wait (0 = infinite). | |
154 | */ | |
6ae2364d | 155 | void |
5260325f | 156 | wait_until_can_do_something(fd_set * readset, fd_set * writeset, |
157 | unsigned int max_time_milliseconds) | |
8efc0c15 | 158 | { |
5260325f | 159 | struct timeval tv, *tvp; |
160 | int ret; | |
8efc0c15 | 161 | |
5260325f | 162 | /* When select fails we restart from here. */ |
8efc0c15 | 163 | retry_select: |
164 | ||
5260325f | 165 | /* Initialize select() masks. */ |
166 | FD_ZERO(readset); | |
71276795 | 167 | FD_ZERO(writeset); |
5260325f | 168 | |
e78a59f5 | 169 | if (compat20) { |
1d1ffb87 | 170 | /* wrong: bad condition XXX */ |
e78a59f5 | 171 | if (channel_not_very_much_buffered_data()) |
172 | FD_SET(connection_in, readset); | |
173 | } else { | |
71276795 | 174 | /* |
175 | * Read packets from the client unless we have too much | |
176 | * buffered stdin or channel data. | |
177 | */ | |
178 | if (buffer_len(&stdin_buffer) < buffer_high && | |
e78a59f5 | 179 | channel_not_very_much_buffered_data()) |
180 | FD_SET(connection_in, readset); | |
71276795 | 181 | /* |
182 | * If there is not too much data already buffered going to | |
183 | * the client, try to get some more data from the program. | |
184 | */ | |
185 | if (packet_not_very_much_data_to_write()) { | |
186 | if (!fdout_eof) | |
187 | FD_SET(fdout, readset); | |
188 | if (!fderr_eof) | |
189 | FD_SET(fderr, readset); | |
190 | } | |
191 | /* | |
192 | * If we have buffered data, try to write some of that data | |
193 | * to the program. | |
194 | */ | |
195 | if (fdin != -1 && buffer_len(&stdin_buffer) > 0) | |
196 | FD_SET(fdin, writeset); | |
e78a59f5 | 197 | } |
5260325f | 198 | /* Set masks for channel descriptors. */ |
199 | channel_prepare_select(readset, writeset); | |
200 | ||
aa3378df | 201 | /* |
202 | * If we have buffered packet data going to the client, mark that | |
203 | * descriptor. | |
204 | */ | |
5260325f | 205 | if (packet_have_data_to_write()) |
206 | FD_SET(connection_out, writeset); | |
207 | ||
5260325f | 208 | /* Update the maximum descriptor number if appropriate. */ |
209 | if (channel_max_fd() > max_fd) | |
210 | max_fd = channel_max_fd(); | |
211 | ||
aa3378df | 212 | /* |
213 | * If child has terminated and there is enough buffer space to read | |
214 | * from it, then read as much as is available and exit. | |
215 | */ | |
5260325f | 216 | if (child_terminated && packet_not_very_much_data_to_write()) |
217 | if (max_time_milliseconds == 0) | |
218 | max_time_milliseconds = 100; | |
219 | ||
220 | if (max_time_milliseconds == 0) | |
221 | tvp = NULL; | |
222 | else { | |
223 | tv.tv_sec = max_time_milliseconds / 1000; | |
224 | tv.tv_usec = 1000 * (max_time_milliseconds % 1000); | |
225 | tvp = &tv; | |
226 | } | |
e78a59f5 | 227 | if (tvp!=NULL) |
228 | debug("tvp!=NULL kid %d mili %d", child_terminated, max_time_milliseconds); | |
8efc0c15 | 229 | |
5260325f | 230 | /* Wait for something to happen, or the timeout to expire. */ |
231 | ret = select(max_fd + 1, readset, writeset, NULL, tvp); | |
8efc0c15 | 232 | |
5260325f | 233 | if (ret < 0) { |
234 | if (errno != EINTR) | |
235 | error("select: %.100s", strerror(errno)); | |
236 | else | |
237 | goto retry_select; | |
8efc0c15 | 238 | } |
691a8a9f | 239 | |
240 | if (child_terminated) | |
241 | child_has_selected = 1; | |
8efc0c15 | 242 | } |
243 | ||
5260325f | 244 | /* |
245 | * Processes input from the client and the program. Input data is stored | |
246 | * in buffers and processed later. | |
247 | */ | |
6ae2364d | 248 | void |
5260325f | 249 | process_input(fd_set * readset) |
250 | { | |
251 | int len; | |
252 | char buf[16384]; | |
253 | ||
254 | /* Read and buffer any input data from the client. */ | |
255 | if (FD_ISSET(connection_in, readset)) { | |
256 | len = read(connection_in, buf, sizeof(buf)); | |
257 | if (len == 0) { | |
258 | verbose("Connection closed by remote host."); | |
259 | fatal_cleanup(); | |
0e73cc53 | 260 | } else if (len < 0) { |
261 | if (errno != EINTR && errno != EAGAIN) { | |
262 | verbose("Read error from remote host: %.100s", strerror(errno)); | |
263 | fatal_cleanup(); | |
264 | } | |
265 | } else { | |
266 | /* Buffer any received data. */ | |
267 | packet_process_incoming(buf, len); | |
5260325f | 268 | } |
5260325f | 269 | } |
e78a59f5 | 270 | if (compat20) |
271 | return; | |
272 | ||
5260325f | 273 | /* Read and buffer any available stdout data from the program. */ |
274 | if (!fdout_eof && FD_ISSET(fdout, readset)) { | |
275 | len = read(fdout, buf, sizeof(buf)); | |
0e73cc53 | 276 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
277 | /* do nothing */ | |
278 | } else if (len <= 0) { | |
5260325f | 279 | fdout_eof = 1; |
0e73cc53 | 280 | } else { |
5260325f | 281 | buffer_append(&stdout_buffer, buf, len); |
282 | fdout_bytes += len; | |
283 | } | |
284 | } | |
285 | /* Read and buffer any available stderr data from the program. */ | |
286 | if (!fderr_eof && FD_ISSET(fderr, readset)) { | |
287 | len = read(fderr, buf, sizeof(buf)); | |
0e73cc53 | 288 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
289 | /* do nothing */ | |
290 | } else if (len <= 0) { | |
5260325f | 291 | fderr_eof = 1; |
0e73cc53 | 292 | } else { |
5260325f | 293 | buffer_append(&stderr_buffer, buf, len); |
0e73cc53 | 294 | } |
5260325f | 295 | } |
296 | } | |
8efc0c15 | 297 | |
5260325f | 298 | /* |
299 | * Sends data from internal buffers to client program stdin. | |
300 | */ | |
6ae2364d | 301 | void |
5260325f | 302 | process_output(fd_set * writeset) |
8efc0c15 | 303 | { |
5260325f | 304 | int len; |
305 | ||
306 | /* Write buffered data to program stdin. */ | |
e78a59f5 | 307 | if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) { |
5260325f | 308 | len = write(fdin, buffer_ptr(&stdin_buffer), |
a408af76 | 309 | buffer_len(&stdin_buffer)); |
0e73cc53 | 310 | if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
311 | /* do nothing */ | |
312 | } else if (len <= 0) { | |
8efc0c15 | 313 | #ifdef USE_PIPES |
5260325f | 314 | close(fdin); |
8efc0c15 | 315 | #else |
7368a6c8 | 316 | if (fdin != fdout) |
5260325f | 317 | close(fdin); |
318 | else | |
319 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 320 | #endif |
5260325f | 321 | fdin = -1; |
322 | } else { | |
323 | /* Successful write. Consume the data from the buffer. */ | |
324 | buffer_consume(&stdin_buffer, len); | |
325 | /* Update the count of bytes written to the program. */ | |
326 | stdin_bytes += len; | |
327 | } | |
8efc0c15 | 328 | } |
5260325f | 329 | /* Send any buffered packet data to the client. */ |
330 | if (FD_ISSET(connection_out, writeset)) | |
331 | packet_write_poll(); | |
8efc0c15 | 332 | } |
333 | ||
5260325f | 334 | /* |
335 | * Wait until all buffered output has been sent to the client. | |
336 | * This is used when the program terminates. | |
337 | */ | |
6ae2364d | 338 | void |
5260325f | 339 | drain_output() |
8efc0c15 | 340 | { |
5260325f | 341 | /* Send any buffered stdout data to the client. */ |
342 | if (buffer_len(&stdout_buffer) > 0) { | |
343 | packet_start(SSH_SMSG_STDOUT_DATA); | |
344 | packet_put_string(buffer_ptr(&stdout_buffer), | |
345 | buffer_len(&stdout_buffer)); | |
346 | packet_send(); | |
347 | /* Update the count of sent bytes. */ | |
348 | stdout_bytes += buffer_len(&stdout_buffer); | |
349 | } | |
350 | /* Send any buffered stderr data to the client. */ | |
351 | if (buffer_len(&stderr_buffer) > 0) { | |
352 | packet_start(SSH_SMSG_STDERR_DATA); | |
353 | packet_put_string(buffer_ptr(&stderr_buffer), | |
354 | buffer_len(&stderr_buffer)); | |
355 | packet_send(); | |
356 | /* Update the count of sent bytes. */ | |
357 | stderr_bytes += buffer_len(&stderr_buffer); | |
358 | } | |
359 | /* Wait until all buffered data has been written to the client. */ | |
360 | packet_write_wait(); | |
8efc0c15 | 361 | } |
362 | ||
6ae2364d | 363 | void |
7368a6c8 | 364 | process_buffered_input_packets() |
365 | { | |
366 | dispatch_run(DISPATCH_NONBLOCK, NULL); | |
367 | } | |
368 | ||
5260325f | 369 | /* |
370 | * Performs the interactive session. This handles data transmission between | |
371 | * the client and the program. Note that the notion of stdin, stdout, and | |
372 | * stderr in this function is sort of reversed: this function writes to | |
373 | * stdin (of the child program), and reads from stdout and stderr (of the | |
374 | * child program). | |
375 | */ | |
6ae2364d | 376 | void |
9da5c3c9 | 377 | server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg) |
8efc0c15 | 378 | { |
71276795 | 379 | fd_set readset, writeset; |
9da5c3c9 | 380 | int wait_status; /* Status returned by wait(). */ |
381 | pid_t wait_pid; /* pid returned by wait(). */ | |
5260325f | 382 | int waiting_termination = 0; /* Have displayed waiting close message. */ |
383 | unsigned int max_time_milliseconds; | |
384 | unsigned int previous_stdout_buffer_bytes; | |
385 | unsigned int stdout_buffer_bytes; | |
386 | int type; | |
387 | ||
388 | debug("Entering interactive session."); | |
389 | ||
390 | /* Initialize the SIGCHLD kludge. */ | |
391 | child_pid = pid; | |
392 | child_terminated = 0; | |
691a8a9f | 393 | child_has_selected = 0; |
5260325f | 394 | signal(SIGCHLD, sigchld_handler); |
395 | ||
396 | /* Initialize our global variables. */ | |
397 | fdin = fdin_arg; | |
398 | fdout = fdout_arg; | |
399 | fderr = fderr_arg; | |
0e73cc53 | 400 | |
401 | /* nonblocking IO */ | |
402 | set_nonblock(fdin); | |
403 | set_nonblock(fdout); | |
ff873e98 | 404 | /* we don't have stderr for interactive terminal sessions, see below */ |
405 | if (fderr != -1) | |
406 | set_nonblock(fderr); | |
0e73cc53 | 407 | |
5260325f | 408 | connection_in = packet_get_connection_in(); |
409 | connection_out = packet_get_connection_out(); | |
410 | ||
411 | previous_stdout_buffer_bytes = 0; | |
412 | ||
413 | /* Set approximate I/O buffer size. */ | |
414 | if (packet_is_interactive()) | |
415 | buffer_high = 4096; | |
416 | else | |
417 | buffer_high = 64 * 1024; | |
418 | ||
419 | /* Initialize max_fd to the maximum of the known file descriptors. */ | |
420 | max_fd = fdin; | |
421 | if (fdout > max_fd) | |
422 | max_fd = fdout; | |
423 | if (fderr != -1 && fderr > max_fd) | |
424 | max_fd = fderr; | |
425 | if (connection_in > max_fd) | |
426 | max_fd = connection_in; | |
427 | if (connection_out > max_fd) | |
428 | max_fd = connection_out; | |
429 | ||
430 | /* Initialize Initialize buffers. */ | |
431 | buffer_init(&stdin_buffer); | |
432 | buffer_init(&stdout_buffer); | |
433 | buffer_init(&stderr_buffer); | |
434 | ||
aa3378df | 435 | /* |
436 | * If we have no separate fderr (which is the case when we have a pty | |
437 | * - there we cannot make difference between data sent to stdout and | |
438 | * stderr), indicate that we have seen an EOF from stderr. This way | |
439 | * we don\'t need to check the descriptor everywhere. | |
440 | */ | |
5260325f | 441 | if (fderr == -1) |
442 | fderr_eof = 1; | |
443 | ||
7368a6c8 | 444 | server_init_dispatch(); |
445 | ||
5260325f | 446 | /* Main loop of the server for the interactive session mode. */ |
447 | for (;;) { | |
5260325f | 448 | |
449 | /* Process buffered packets from the client. */ | |
450 | process_buffered_input_packets(); | |
451 | ||
aa3378df | 452 | /* |
453 | * If we have received eof, and there is no more pending | |
454 | * input data, cause a real eof by closing fdin. | |
455 | */ | |
5260325f | 456 | if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { |
8efc0c15 | 457 | #ifdef USE_PIPES |
5260325f | 458 | close(fdin); |
8efc0c15 | 459 | #else |
7368a6c8 | 460 | if (fdin != fdout) |
5260325f | 461 | close(fdin); |
462 | else | |
463 | shutdown(fdin, SHUT_WR); /* We will no longer send. */ | |
8efc0c15 | 464 | #endif |
5260325f | 465 | fdin = -1; |
466 | } | |
aa3378df | 467 | /* Make packets from buffered stderr data to send to the client. */ |
5260325f | 468 | make_packets_from_stderr_data(); |
469 | ||
aa3378df | 470 | /* |
471 | * Make packets from buffered stdout data to send to the | |
472 | * client. If there is very little to send, this arranges to | |
473 | * not send them now, but to wait a short while to see if we | |
474 | * are getting more data. This is necessary, as some systems | |
475 | * wake up readers from a pty after each separate character. | |
476 | */ | |
5260325f | 477 | max_time_milliseconds = 0; |
478 | stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
479 | if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && | |
480 | stdout_buffer_bytes != previous_stdout_buffer_bytes) { | |
481 | /* try again after a while */ | |
482 | max_time_milliseconds = 10; | |
483 | } else { | |
484 | /* Send it now. */ | |
485 | make_packets_from_stdout_data(); | |
486 | } | |
487 | previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); | |
488 | ||
489 | /* Send channel data to the client. */ | |
490 | if (packet_not_very_much_data_to_write()) | |
491 | channel_output_poll(); | |
492 | ||
aa3378df | 493 | /* |
494 | * Bail out of the loop if the program has closed its output | |
495 | * descriptors, and we have no more data to send to the | |
496 | * client, and there is no pending buffered data. | |
497 | */ | |
691a8a9f | 498 | if (((fdout_eof && fderr_eof) || |
499 | (child_terminated && child_has_selected)) && | |
500 | !packet_have_data_to_write() && | |
501 | (buffer_len(&stdout_buffer) == 0) && | |
502 | (buffer_len(&stderr_buffer) == 0)) { | |
5260325f | 503 | if (!channel_still_open()) |
7368a6c8 | 504 | break; |
5260325f | 505 | if (!waiting_termination) { |
506 | const char *s = "Waiting for forwarded connections to terminate...\r\n"; | |
507 | char *cp; | |
508 | waiting_termination = 1; | |
509 | buffer_append(&stderr_buffer, s, strlen(s)); | |
510 | ||
511 | /* Display list of open channels. */ | |
512 | cp = channel_open_message(); | |
513 | buffer_append(&stderr_buffer, cp, strlen(cp)); | |
514 | xfree(cp); | |
515 | } | |
516 | } | |
517 | /* Sleep in select() until we can do something. */ | |
518 | wait_until_can_do_something(&readset, &writeset, | |
519 | max_time_milliseconds); | |
520 | ||
521 | /* Process any channel events. */ | |
522 | channel_after_select(&readset, &writeset); | |
523 | ||
524 | /* Process input from the client and from program stdout/stderr. */ | |
525 | process_input(&readset); | |
526 | ||
527 | /* Process output to the client and to program stdin. */ | |
528 | process_output(&writeset); | |
8efc0c15 | 529 | } |
530 | ||
5260325f | 531 | /* Cleanup and termination code. */ |
8efc0c15 | 532 | |
5260325f | 533 | /* Wait until all output has been sent to the client. */ |
534 | drain_output(); | |
8efc0c15 | 535 | |
5260325f | 536 | debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", |
537 | stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); | |
8efc0c15 | 538 | |
5260325f | 539 | /* Free and clear the buffers. */ |
540 | buffer_free(&stdin_buffer); | |
541 | buffer_free(&stdout_buffer); | |
542 | buffer_free(&stderr_buffer); | |
8efc0c15 | 543 | |
5260325f | 544 | /* Close the file descriptors. */ |
545 | if (fdout != -1) | |
546 | close(fdout); | |
547 | fdout = -1; | |
548 | fdout_eof = 1; | |
549 | if (fderr != -1) | |
550 | close(fderr); | |
551 | fderr = -1; | |
552 | fderr_eof = 1; | |
553 | if (fdin != -1) | |
554 | close(fdin); | |
555 | fdin = -1; | |
556 | ||
557 | /* Stop listening for channels; this removes unix domain sockets. */ | |
558 | channel_stop_listening(); | |
559 | ||
560 | /* Wait for the child to exit. Get its exit status. */ | |
561 | wait_pid = wait(&wait_status); | |
562 | if (wait_pid < 0) { | |
563 | /* | |
564 | * It is possible that the wait was handled by SIGCHLD | |
565 | * handler. This may result in either: this call | |
566 | * returning with EINTR, or: this call returning ECHILD. | |
567 | */ | |
568 | if (child_terminated) | |
569 | wait_status = child_wait_status; | |
570 | else | |
571 | packet_disconnect("wait: %.100s", strerror(errno)); | |
572 | } else { | |
573 | /* Check if it matches the process we forked. */ | |
574 | if (wait_pid != pid) | |
575 | error("Strange, wait returned pid %d, expected %d", | |
57112b5a | 576 | wait_pid, pid); |
5260325f | 577 | } |
8efc0c15 | 578 | |
5260325f | 579 | /* We no longer want our SIGCHLD handler to be called. */ |
580 | signal(SIGCHLD, SIG_DFL); | |
581 | ||
582 | /* Check if it exited normally. */ | |
583 | if (WIFEXITED(wait_status)) { | |
584 | /* Yes, normal exit. Get exit status and send it to the client. */ | |
585 | debug("Command exited with status %d.", WEXITSTATUS(wait_status)); | |
586 | packet_start(SSH_SMSG_EXITSTATUS); | |
587 | packet_put_int(WEXITSTATUS(wait_status)); | |
588 | packet_send(); | |
589 | packet_write_wait(); | |
590 | ||
aa3378df | 591 | /* |
592 | * Wait for exit confirmation. Note that there might be | |
593 | * other packets coming before it; however, the program has | |
594 | * already died so we just ignore them. The client is | |
595 | * supposed to respond with the confirmation when it receives | |
596 | * the exit status. | |
597 | */ | |
5260325f | 598 | do { |
599 | int plen; | |
600 | type = packet_read(&plen); | |
601 | } | |
602 | while (type != SSH_CMSG_EXIT_CONFIRMATION); | |
603 | ||
604 | debug("Received exit confirmation."); | |
605 | return; | |
606 | } | |
607 | /* Check if the program terminated due to a signal. */ | |
608 | if (WIFSIGNALED(wait_status)) | |
609 | packet_disconnect("Command terminated on signal %d.", | |
610 | WTERMSIG(wait_status)); | |
611 | ||
612 | /* Some weird exit cause. Just exit. */ | |
613 | packet_disconnect("wait returned status %04x.", wait_status); | |
614 | /* NOTREACHED */ | |
615 | } | |
7368a6c8 | 616 | |
6ae2364d | 617 | void |
e78a59f5 | 618 | server_loop2(void) |
619 | { | |
620 | fd_set readset, writeset; | |
621 | int had_channel = 0; | |
622 | int status; | |
623 | pid_t pid; | |
624 | ||
625 | debug("Entering interactive session for SSH2."); | |
626 | ||
627 | signal(SIGCHLD, sigchld_handler2); | |
628 | child_terminated = 0; | |
629 | connection_in = packet_get_connection_in(); | |
630 | connection_out = packet_get_connection_out(); | |
631 | max_fd = connection_in; | |
632 | if (connection_out > max_fd) | |
633 | max_fd = connection_out; | |
634 | server_init_dispatch(); | |
635 | ||
636 | for (;;) { | |
637 | process_buffered_input_packets(); | |
638 | if (!had_channel && channel_still_open()) | |
639 | had_channel = 1; | |
640 | if (had_channel && !channel_still_open()) { | |
641 | debug("!channel_still_open."); | |
642 | break; | |
643 | } | |
644 | if (packet_not_very_much_data_to_write()) | |
645 | channel_output_poll(); | |
646 | wait_until_can_do_something(&readset, &writeset, 0); | |
647 | if (child_terminated) { | |
648 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
649 | session_close_by_pid(pid, status); | |
650 | child_terminated = 0; | |
fc1e8bf4 | 651 | signal(SIGCHLD, sigchld_handler2); |
e78a59f5 | 652 | } |
653 | channel_after_select(&readset, &writeset); | |
654 | process_input(&readset); | |
655 | process_output(&writeset); | |
656 | } | |
657 | signal(SIGCHLD, SIG_DFL); | |
658 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0) | |
659 | session_close_by_pid(pid, status); | |
660 | channel_stop_listening(); | |
661 | } | |
662 | ||
7368a6c8 | 663 | void |
664 | server_input_stdin_data(int type, int plen) | |
665 | { | |
666 | char *data; | |
667 | unsigned int data_len; | |
668 | ||
669 | /* Stdin data from the client. Append it to the buffer. */ | |
670 | /* Ignore any data if the client has closed stdin. */ | |
671 | if (fdin == -1) | |
672 | return; | |
673 | data = packet_get_string(&data_len); | |
674 | packet_integrity_check(plen, (4 + data_len), type); | |
675 | buffer_append(&stdin_buffer, data, data_len); | |
676 | memset(data, 0, data_len); | |
677 | xfree(data); | |
678 | } | |
679 | ||
680 | void | |
681 | server_input_eof(int type, int plen) | |
682 | { | |
683 | /* | |
684 | * Eof from the client. The stdin descriptor to the | |
685 | * program will be closed when all buffered data has | |
686 | * drained. | |
687 | */ | |
688 | debug("EOF received for stdin."); | |
689 | packet_integrity_check(plen, 0, type); | |
690 | stdin_eof = 1; | |
691 | } | |
692 | ||
693 | void | |
694 | server_input_window_size(int type, int plen) | |
695 | { | |
696 | int row = packet_get_int(); | |
697 | int col = packet_get_int(); | |
698 | int xpixel = packet_get_int(); | |
699 | int ypixel = packet_get_int(); | |
700 | ||
701 | debug("Window change received."); | |
702 | packet_integrity_check(plen, 4 * 4, type); | |
703 | if (fdin != -1) | |
704 | pty_change_window_size(fdin, row, col, xpixel, ypixel); | |
705 | } | |
706 | ||
e78a59f5 | 707 | int |
708 | input_direct_tcpip(void) | |
709 | { | |
710 | int sock; | |
6ae2364d | 711 | char *target, *originator; |
712 | int target_port, originator_port; | |
e78a59f5 | 713 | |
6ae2364d | 714 | target = packet_get_string(NULL); |
715 | target_port = packet_get_int(); | |
e78a59f5 | 716 | originator = packet_get_string(NULL); |
717 | originator_port = packet_get_int(); | |
6ae2364d | 718 | packet_done(); |
71276795 | 719 | |
720 | debug("open direct-tcpip: from %s port %d to %s port %d", | |
721 | originator, originator_port, target, target_port); | |
e78a59f5 | 722 | /* XXX check permission */ |
6ae2364d | 723 | sock = channel_connect_to(target, target_port); |
724 | xfree(target); | |
e78a59f5 | 725 | xfree(originator); |
726 | if (sock < 0) | |
727 | return -1; | |
728 | return channel_new("direct-tcpip", SSH_CHANNEL_OPEN, | |
729 | sock, sock, -1, 4*1024, 32*1024, 0, xstrdup("direct-tcpip")); | |
730 | } | |
731 | ||
6ae2364d | 732 | void |
e78a59f5 | 733 | server_input_channel_open(int type, int plen) |
734 | { | |
735 | Channel *c = NULL; | |
736 | char *ctype; | |
737 | int id; | |
738 | unsigned int len; | |
739 | int rchan; | |
740 | int rmaxpack; | |
741 | int rwindow; | |
742 | ||
743 | ctype = packet_get_string(&len); | |
744 | rchan = packet_get_int(); | |
745 | rwindow = packet_get_int(); | |
746 | rmaxpack = packet_get_int(); | |
747 | ||
a306f2dd | 748 | debug("channel_input_open: ctype %s rchan %d win %d max %d", |
e78a59f5 | 749 | ctype, rchan, rwindow, rmaxpack); |
750 | ||
751 | if (strcmp(ctype, "session") == 0) { | |
752 | debug("open session"); | |
6ae2364d | 753 | packet_done(); |
e78a59f5 | 754 | /* |
755 | * A server session has no fd to read or write | |
756 | * until a CHANNEL_REQUEST for a shell is made, | |
757 | * so we set the type to SSH_CHANNEL_LARVAL. | |
758 | * Additionally, a callback for handling all | |
759 | * CHANNEL_REQUEST messages is registered. | |
760 | */ | |
761 | id = channel_new(ctype, SSH_CHANNEL_LARVAL, | |
762 | -1, -1, -1, 0, 32*1024, 0, xstrdup("server-session")); | |
763 | if (session_open(id) == 1) { | |
764 | channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST, | |
765 | session_input_channel_req, (void *)0); | |
766 | channel_register_cleanup(id, session_close_by_channel); | |
767 | c = channel_lookup(id); | |
768 | } else { | |
769 | debug("session open failed, free channel %d", id); | |
770 | channel_free(id); | |
771 | } | |
772 | } else if (strcmp(ctype, "direct-tcpip") == 0) { | |
e78a59f5 | 773 | id = input_direct_tcpip(); |
774 | if (id >= 0) | |
775 | c = channel_lookup(id); | |
776 | } | |
777 | if (c != NULL) { | |
778 | debug("confirm %s", ctype); | |
779 | c->remote_id = rchan; | |
780 | c->remote_window = rwindow; | |
781 | c->remote_maxpacket = rmaxpack; | |
782 | ||
783 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
784 | packet_put_int(c->remote_id); | |
785 | packet_put_int(c->self); | |
786 | packet_put_int(c->local_window); | |
787 | packet_put_int(c->local_maxpacket); | |
788 | packet_send(); | |
789 | } else { | |
790 | debug("failure %s", ctype); | |
791 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
792 | packet_put_int(rchan); | |
793 | packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); | |
794 | packet_put_cstring("bla bla"); | |
795 | packet_put_cstring(""); | |
796 | packet_send(); | |
797 | } | |
798 | xfree(ctype); | |
799 | } | |
800 | ||
6ae2364d | 801 | void |
e78a59f5 | 802 | server_init_dispatch_20() |
803 | { | |
804 | debug("server_init_dispatch_20"); | |
805 | dispatch_init(&dispatch_protocol_error); | |
806 | dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); | |
807 | dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); | |
808 | dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); | |
809 | dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); | |
810 | dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open); | |
811 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
812 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
813 | dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request); | |
814 | dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); | |
815 | } | |
6ae2364d | 816 | void |
7368a6c8 | 817 | server_init_dispatch_13() |
818 | { | |
819 | debug("server_init_dispatch_13"); | |
820 | dispatch_init(NULL); | |
821 | dispatch_set(SSH_CMSG_EOF, &server_input_eof); | |
822 | dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); | |
823 | dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); | |
824 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); | |
825 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); | |
826 | dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); | |
827 | dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
828 | dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
829 | dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); | |
830 | } | |
6ae2364d | 831 | void |
7368a6c8 | 832 | server_init_dispatch_15() |
833 | { | |
834 | server_init_dispatch_13(); | |
835 | debug("server_init_dispatch_15"); | |
836 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); | |
837 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); | |
838 | } | |
6ae2364d | 839 | void |
7368a6c8 | 840 | server_init_dispatch() |
841 | { | |
e78a59f5 | 842 | if (compat20) |
843 | server_init_dispatch_20(); | |
844 | else if (compat13) | |
7368a6c8 | 845 | server_init_dispatch_13(); |
846 | else | |
847 | server_init_dispatch_15(); | |
848 | } |