Annotation of src/usr.bin/ssh/clientloop.c, Revision 1.30
1.1 deraadt 1: /*
1.20 markus 2: *
1.12 deraadt 3: * clientloop.c
1.20 markus 4: *
1.12 deraadt 5: * Author: Tatu Ylonen <ylo@cs.hut.fi>
1.20 markus 6: *
1.12 deraadt 7: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: * All rights reserved
1.20 markus 9: *
10: *
1.12 deraadt 11: * Created: Sat Sep 23 12:23:57 1995 ylo
1.20 markus 12: *
1.12 deraadt 13: * The main loop for the interactive session (client side).
1.20 markus 14: *
1.16 markus 15: * SSH2 support added by Markus Friedl.
1.12 deraadt 16: */
1.1 deraadt 17:
18: #include "includes.h"
1.30 ! markus 19: RCSID("$OpenBSD: clientloop.c,v 1.29 2000/07/16 08:27:21 markus Exp $");
1.1 deraadt 20:
21: #include "xmalloc.h"
22: #include "ssh.h"
23: #include "packet.h"
24: #include "buffer.h"
1.8 markus 25: #include "readconf.h"
1.1 deraadt 26:
1.16 markus 27: #include "ssh2.h"
1.15 markus 28: #include "compat.h"
29: #include "channels.h"
30: #include "dispatch.h"
31:
1.30 ! markus 32: #include "buffer.h"
! 33: #include "bufaux.h"
! 34:
1.1 deraadt 35: /* Flag indicating that stdin should be redirected from /dev/null. */
36: extern int stdin_null_flag;
37:
1.13 markus 38: /*
39: * Name of the host we are connecting to. This is the name given on the
40: * command line, or the HostName specified for the user-supplied name in a
41: * configuration file.
42: */
1.1 deraadt 43: extern char *host;
44:
1.13 markus 45: /*
46: * Flag to indicate that we have received a window change signal which has
47: * not yet been processed. This will cause a message indicating the new
48: * window size to be sent to the server a little later. This is volatile
49: * because this is updated in a signal handler.
50: */
1.1 deraadt 51: static volatile int received_window_change_signal = 0;
52:
53: /* Terminal modes, as saved by enter_raw_mode. */
54: static struct termios saved_tio;
55:
1.13 markus 56: /*
57: * Flag indicating whether we are in raw mode. This is used by
58: * enter_raw_mode and leave_raw_mode.
59: */
1.1 deraadt 60: static int in_raw_mode = 0;
61:
62: /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
63: static int in_non_blocking_mode = 0;
64:
65: /* Common data for the client loop code. */
1.11 markus 66: static int escape_pending; /* Last character was the escape character */
67: static int last_was_cr; /* Last character was a newline. */
68: static int exit_status; /* Used to store the exit status of the command. */
69: static int stdin_eof; /* EOF has been encountered on standard error. */
70: static Buffer stdin_buffer; /* Buffer for stdin data. */
71: static Buffer stdout_buffer; /* Buffer for stdout data. */
72: static Buffer stderr_buffer; /* Buffer for stderr data. */
73: static unsigned int buffer_high;/* Soft max buffer size. */
74: static int max_fd; /* Maximum file descriptor number in select(). */
75: static int connection_in; /* Connection to server (input). */
76: static int connection_out; /* Connection to server (output). */
1.1 deraadt 77: static unsigned long stdin_bytes, stdout_bytes, stderr_bytes;
1.11 markus 78: static int quit_pending; /* Set to non-zero to quit the client loop. */
79: static int escape_char; /* Escape character. */
1.1 deraadt 80:
1.16 markus 81:
82: void client_init_dispatch(void);
83: int session_ident = -1;
84:
1.13 markus 85: /* Returns the user\'s terminal to normal mode if it had been put in raw mode. */
1.1 deraadt 86:
1.20 markus 87: void
1.11 markus 88: leave_raw_mode()
1.1 deraadt 89: {
1.11 markus 90: if (!in_raw_mode)
91: return;
92: in_raw_mode = 0;
93: if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0)
94: perror("tcsetattr");
1.1 deraadt 95:
1.11 markus 96: fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL);
1.1 deraadt 97: }
98:
99: /* Puts the user\'s terminal in raw mode. */
100:
1.20 markus 101: void
1.11 markus 102: enter_raw_mode()
1.1 deraadt 103: {
1.11 markus 104: struct termios tio;
1.1 deraadt 105:
1.11 markus 106: if (tcgetattr(fileno(stdin), &tio) < 0)
107: perror("tcgetattr");
108: saved_tio = tio;
109: tio.c_iflag |= IGNPAR;
110: tio.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF);
111: tio.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL);
1.1 deraadt 112: #ifdef IEXTEN
1.11 markus 113: tio.c_lflag &= ~IEXTEN;
114: #endif /* IEXTEN */
115: tio.c_oflag &= ~OPOST;
116: tio.c_cc[VMIN] = 1;
117: tio.c_cc[VTIME] = 0;
118: if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0)
119: perror("tcsetattr");
120: in_raw_mode = 1;
1.1 deraadt 121:
1.11 markus 122: fatal_add_cleanup((void (*) (void *)) leave_raw_mode, NULL);
123: }
1.1 deraadt 124:
125: /* Restores stdin to blocking mode. */
126:
1.20 markus 127: void
1.11 markus 128: leave_non_blocking()
1.1 deraadt 129: {
1.11 markus 130: if (in_non_blocking_mode) {
131: (void) fcntl(fileno(stdin), F_SETFL, 0);
132: in_non_blocking_mode = 0;
133: fatal_remove_cleanup((void (*) (void *)) leave_non_blocking, NULL);
134: }
1.1 deraadt 135: }
136:
1.11 markus 137: /* Puts stdin terminal in non-blocking mode. */
138:
1.20 markus 139: void
1.11 markus 140: enter_non_blocking()
1.1 deraadt 141: {
1.11 markus 142: in_non_blocking_mode = 1;
143: (void) fcntl(fileno(stdin), F_SETFL, O_NONBLOCK);
144: fatal_add_cleanup((void (*) (void *)) leave_non_blocking, NULL);
1.1 deraadt 145: }
146:
1.13 markus 147: /*
148: * Signal handler for the window change signal (SIGWINCH). This just sets a
149: * flag indicating that the window has changed.
150: */
1.1 deraadt 151:
1.20 markus 152: void
1.11 markus 153: window_change_handler(int sig)
1.1 deraadt 154: {
1.11 markus 155: received_window_change_signal = 1;
156: signal(SIGWINCH, window_change_handler);
1.1 deraadt 157: }
158:
1.13 markus 159: /*
160: * Signal handler for signals that cause the program to terminate. These
161: * signals must be trapped to restore terminal modes.
162: */
1.1 deraadt 163:
1.20 markus 164: void
1.11 markus 165: signal_handler(int sig)
1.1 deraadt 166: {
1.11 markus 167: if (in_raw_mode)
168: leave_raw_mode();
169: if (in_non_blocking_mode)
170: leave_non_blocking();
171: channel_stop_listening();
172: packet_close();
173: fatal("Killed by signal %d.", sig);
1.1 deraadt 174: }
175:
1.13 markus 176: /*
177: * Returns current time in seconds from Jan 1, 1970 with the maximum
178: * available resolution.
179: */
1.1 deraadt 180:
1.20 markus 181: double
1.11 markus 182: get_current_time()
1.1 deraadt 183: {
1.11 markus 184: struct timeval tv;
185: gettimeofday(&tv, NULL);
186: return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
1.1 deraadt 187: }
188:
1.13 markus 189: /*
190: * This is called when the interactive is entered. This checks if there is
191: * an EOF coming on stdin. We must check this explicitly, as select() does
192: * not appear to wake up when redirecting from /dev/null.
193: */
1.1 deraadt 194:
1.20 markus 195: void
1.11 markus 196: client_check_initial_eof_on_stdin()
1.1 deraadt 197: {
1.11 markus 198: int len;
199: char buf[1];
1.1 deraadt 200:
1.13 markus 201: /*
202: * If standard input is to be "redirected from /dev/null", we simply
203: * mark that we have seen an EOF and send an EOF message to the
204: * server. Otherwise, we try to read a single character; it appears
205: * that for some files, such /dev/null, select() never wakes up for
206: * read for this descriptor, which means that we never get EOF. This
207: * way we will get the EOF if stdin comes from /dev/null or similar.
208: */
1.11 markus 209: if (stdin_null_flag) {
210: /* Fake EOF on stdin. */
211: debug("Sending eof.");
212: stdin_eof = 1;
213: packet_start(SSH_CMSG_EOF);
214: packet_send();
215: } else {
216: enter_non_blocking();
217:
218: /* Check for immediate EOF on stdin. */
219: len = read(fileno(stdin), buf, 1);
220: if (len == 0) {
1.13 markus 221: /* EOF. Record that we have seen it and send EOF to server. */
1.11 markus 222: debug("Sending eof.");
223: stdin_eof = 1;
224: packet_start(SSH_CMSG_EOF);
225: packet_send();
226: } else if (len > 0) {
1.13 markus 227: /*
228: * Got data. We must store the data in the buffer,
229: * and also process it as an escape character if
230: * appropriate.
231: */
1.11 markus 232: if ((unsigned char) buf[0] == escape_char)
233: escape_pending = 1;
234: else {
235: buffer_append(&stdin_buffer, buf, 1);
236: stdin_bytes += 1;
237: }
238: }
239: leave_non_blocking();
240: }
1.1 deraadt 241: }
242:
243:
1.13 markus 244: /*
245: * Make packets from buffered stdin data, and buffer them for sending to the
246: * connection.
247: */
1.1 deraadt 248:
1.20 markus 249: void
1.11 markus 250: client_make_packets_from_stdin_data()
1.1 deraadt 251: {
1.11 markus 252: unsigned int len;
1.1 deraadt 253:
1.11 markus 254: /* Send buffered stdin data to the server. */
255: while (buffer_len(&stdin_buffer) > 0 &&
256: packet_not_very_much_data_to_write()) {
257: len = buffer_len(&stdin_buffer);
258: /* Keep the packets at reasonable size. */
259: if (len > packet_get_maxsize())
260: len = packet_get_maxsize();
261: packet_start(SSH_CMSG_STDIN_DATA);
262: packet_put_string(buffer_ptr(&stdin_buffer), len);
263: packet_send();
264: buffer_consume(&stdin_buffer, len);
265: /* If we have a pending EOF, send it now. */
266: if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
267: packet_start(SSH_CMSG_EOF);
268: packet_send();
269: }
1.1 deraadt 270: }
271: }
272:
1.13 markus 273: /*
274: * Checks if the client window has changed, and sends a packet about it to
275: * the server if so. The actual change is detected elsewhere (by a software
276: * interrupt on Unix); this just checks the flag and sends a message if
277: * appropriate.
278: */
1.1 deraadt 279:
1.20 markus 280: void
1.11 markus 281: client_check_window_change()
1.1 deraadt 282: {
1.16 markus 283: struct winsize ws;
284:
285: if (! received_window_change_signal)
286: return;
287: /** XXX race */
288: received_window_change_signal = 0;
289:
290: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
291: return;
292:
293: debug("client_check_window_change: changed");
294:
295: if (compat20) {
296: channel_request_start(session_ident, "window-change", 0);
297: packet_put_int(ws.ws_col);
298: packet_put_int(ws.ws_row);
299: packet_put_int(ws.ws_xpixel);
300: packet_put_int(ws.ws_ypixel);
301: packet_send();
302: } else {
303: packet_start(SSH_CMSG_WINDOW_SIZE);
304: packet_put_int(ws.ws_row);
305: packet_put_int(ws.ws_col);
306: packet_put_int(ws.ws_xpixel);
307: packet_put_int(ws.ws_ypixel);
308: packet_send();
1.1 deraadt 309: }
310: }
311:
1.13 markus 312: /*
313: * Waits until the client can do something (some data becomes available on
314: * one of the file descriptors).
315: */
1.1 deraadt 316:
1.20 markus 317: void
1.11 markus 318: client_wait_until_can_do_something(fd_set * readset, fd_set * writeset)
319: {
1.16 markus 320: /*debug("client_wait_until_can_do_something"); */
321:
1.11 markus 322: /* Initialize select masks. */
323: FD_ZERO(readset);
1.17 markus 324: FD_ZERO(writeset);
1.11 markus 325:
1.16 markus 326: if (!compat20) {
1.17 markus 327: /* Read from the connection, unless our buffers are full. */
1.16 markus 328: if (buffer_len(&stdout_buffer) < buffer_high &&
329: buffer_len(&stderr_buffer) < buffer_high &&
330: channel_not_very_much_buffered_data())
331: FD_SET(connection_in, readset);
1.17 markus 332: /*
333: * Read from stdin, unless we have seen EOF or have very much
334: * buffered data to send to the server.
335: */
336: if (!stdin_eof && packet_not_very_much_data_to_write())
337: FD_SET(fileno(stdin), readset);
338:
339: /* Select stdout/stderr if have data in buffer. */
340: if (buffer_len(&stdout_buffer) > 0)
341: FD_SET(fileno(stdout), writeset);
342: if (buffer_len(&stderr_buffer) > 0)
343: FD_SET(fileno(stderr), writeset);
1.16 markus 344: } else {
1.11 markus 345: FD_SET(connection_in, readset);
1.16 markus 346: }
1.11 markus 347:
348: /* Add any selections by the channel mechanism. */
349: channel_prepare_select(readset, writeset);
350:
351: /* Select server connection if have data to write to the server. */
352: if (packet_have_data_to_write())
353: FD_SET(connection_out, writeset);
354:
1.16 markus 355: /* move UP XXX */
1.11 markus 356: /* Update maximum file descriptor number, if appropriate. */
357: if (channel_max_fd() > max_fd)
358: max_fd = channel_max_fd();
359:
1.13 markus 360: /*
361: * Wait for something to happen. This will suspend the process until
362: * some selected descriptor can be read, written, or has some other
363: * event pending. Note: if you want to implement SSH_MSG_IGNORE
364: * messages to fool traffic analysis, this might be the place to do
365: * it: just have a random timeout for the select, and send a random
366: * SSH_MSG_IGNORE packet when the timeout expires.
367: */
1.11 markus 368:
369: if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0) {
370: char buf[100];
371: /* Some systems fail to clear these automatically. */
372: FD_ZERO(readset);
373: FD_ZERO(writeset);
374: if (errno == EINTR)
375: return;
376: /* Note: we might still have data in the buffers. */
377: snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
378: buffer_append(&stderr_buffer, buf, strlen(buf));
379: stderr_bytes += strlen(buf);
380: quit_pending = 1;
381: }
382: }
383:
1.20 markus 384: void
1.11 markus 385: client_suspend_self()
1.1 deraadt 386: {
1.11 markus 387: struct winsize oldws, newws;
388:
389: /* Flush stdout and stderr buffers. */
390: if (buffer_len(&stdout_buffer) > 0)
1.14 deraadt 391: atomicio(write, fileno(stdout), buffer_ptr(&stdout_buffer),
392: buffer_len(&stdout_buffer));
1.11 markus 393: if (buffer_len(&stderr_buffer) > 0)
1.14 deraadt 394: atomicio(write, fileno(stderr), buffer_ptr(&stderr_buffer),
395: buffer_len(&stderr_buffer));
1.11 markus 396:
397: leave_raw_mode();
398:
1.13 markus 399: /*
400: * Free (and clear) the buffer to reduce the amount of data that gets
401: * written to swap.
402: */
1.11 markus 403: buffer_free(&stdin_buffer);
404: buffer_free(&stdout_buffer);
405: buffer_free(&stderr_buffer);
406:
407: /* Save old window size. */
408: ioctl(fileno(stdin), TIOCGWINSZ, &oldws);
409:
410: /* Send the suspend signal to the program itself. */
411: kill(getpid(), SIGTSTP);
412:
413: /* Check if the window size has changed. */
414: if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 &&
415: (oldws.ws_row != newws.ws_row ||
416: oldws.ws_col != newws.ws_col ||
417: oldws.ws_xpixel != newws.ws_xpixel ||
418: oldws.ws_ypixel != newws.ws_ypixel))
419: received_window_change_signal = 1;
420:
421: /* OK, we have been continued by the user. Reinitialize buffers. */
422: buffer_init(&stdin_buffer);
423: buffer_init(&stdout_buffer);
424: buffer_init(&stderr_buffer);
425:
426: enter_raw_mode();
427: }
428:
1.20 markus 429: void
1.17 markus 430: client_process_net_input(fd_set * readset)
1.11 markus 431: {
1.17 markus 432: int len;
433: char buf[8192];
1.11 markus 434:
1.13 markus 435: /*
436: * Read input from the server, and add any such data to the buffer of
437: * the packet subsystem.
438: */
1.11 markus 439: if (FD_ISSET(connection_in, readset)) {
440: /* Read as much as possible. */
441: len = read(connection_in, buf, sizeof(buf));
1.16 markus 442: /*debug("read connection_in len %d", len); XXX */
1.11 markus 443: if (len == 0) {
444: /* Received EOF. The remote host has closed the connection. */
445: snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
446: host);
1.1 deraadt 447: buffer_append(&stderr_buffer, buf, strlen(buf));
448: stderr_bytes += strlen(buf);
449: quit_pending = 1;
450: return;
1.11 markus 451: }
1.13 markus 452: /*
453: * There is a kernel bug on Solaris that causes select to
454: * sometimes wake up even though there is no data available.
455: */
1.11 markus 456: if (len < 0 && errno == EAGAIN)
457: len = 0;
458:
459: if (len < 0) {
460: /* An error has encountered. Perhaps there is a network problem. */
461: snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
462: host, strerror(errno));
463: buffer_append(&stderr_buffer, buf, strlen(buf));
464: stderr_bytes += strlen(buf);
465: quit_pending = 1;
466: return;
467: }
468: packet_process_incoming(buf, len);
469: }
1.17 markus 470: }
1.16 markus 471:
1.20 markus 472: void
1.17 markus 473: client_process_input(fd_set * readset)
474: {
1.21 deraadt 475: int len;
476: pid_t pid;
1.17 markus 477: char buf[8192], *s;
1.16 markus 478:
1.11 markus 479: /* Read input from stdin. */
480: if (FD_ISSET(fileno(stdin), readset)) {
481: /* Read as much as possible. */
482: len = read(fileno(stdin), buf, sizeof(buf));
483: if (len <= 0) {
1.13 markus 484: /*
485: * Received EOF or error. They are treated
486: * similarly, except that an error message is printed
487: * if it was an error condition.
488: */
1.11 markus 489: if (len < 0) {
490: snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
491: buffer_append(&stderr_buffer, buf, strlen(buf));
492: stderr_bytes += strlen(buf);
493: }
494: /* Mark that we have seen EOF. */
495: stdin_eof = 1;
1.13 markus 496: /*
497: * Send an EOF message to the server unless there is
498: * data in the buffer. If there is data in the
499: * buffer, no message will be sent now. Code
500: * elsewhere will send the EOF when the buffer
501: * becomes empty if stdin_eof is set.
502: */
1.11 markus 503: if (buffer_len(&stdin_buffer) == 0) {
1.1 deraadt 504: packet_start(SSH_CMSG_EOF);
505: packet_send();
1.11 markus 506: }
507: } else if (escape_char == -1) {
1.13 markus 508: /*
509: * Normal successful read, and no escape character.
510: * Just append the data to buffer.
511: */
1.11 markus 512: buffer_append(&stdin_buffer, buf, len);
513: stdin_bytes += len;
514: } else {
1.13 markus 515: /*
516: * Normal, successful read. But we have an escape character
517: * and have to process the characters one by one.
518: */
1.11 markus 519: unsigned int i;
520: for (i = 0; i < len; i++) {
521: unsigned char ch;
522: /* Get one character at a time. */
523: ch = buf[i];
524:
525: if (escape_pending) {
526: /* We have previously seen an escape character. */
527: /* Clear the flag now. */
528: escape_pending = 0;
529: /* Process the escaped character. */
530: switch (ch) {
531: case '.':
532: /* Terminate the connection. */
533: snprintf(buf, sizeof buf, "%c.\r\n", escape_char);
534: buffer_append(&stderr_buffer, buf, strlen(buf));
535: stderr_bytes += strlen(buf);
536: quit_pending = 1;
537: return;
538:
539: case 'Z' - 64:
540: /* Suspend the program. */
541: /* Print a message to that effect to the user. */
542: snprintf(buf, sizeof buf, "%c^Z\r\n", escape_char);
543: buffer_append(&stderr_buffer, buf, strlen(buf));
544: stderr_bytes += strlen(buf);
545:
546: /* Restore terminal modes and suspend. */
547: client_suspend_self();
548:
549: /* We have been continued. */
550: continue;
551:
552: case '&':
1.13 markus 553: /*
554: * Detach the program (continue to serve connections,
555: * but put in background and no more new connections).
556: */
1.11 markus 557: if (!stdin_eof) {
1.13 markus 558: /*
559: * Sending SSH_CMSG_EOF alone does not always appear
560: * to be enough. So we try to send an EOF character
561: * first.
562: */
1.11 markus 563: packet_start(SSH_CMSG_STDIN_DATA);
564: packet_put_string("\004", 1);
565: packet_send();
566: /* Close stdin. */
567: stdin_eof = 1;
568: if (buffer_len(&stdin_buffer) == 0) {
569: packet_start(SSH_CMSG_EOF);
570: packet_send();
571: }
572: }
573: /* Restore tty modes. */
574: leave_raw_mode();
575:
576: /* Stop listening for new connections. */
577: channel_stop_listening();
578:
579: printf("%c& [backgrounded]\n", escape_char);
580:
581: /* Fork into background. */
582: pid = fork();
583: if (pid < 0) {
584: error("fork: %.100s", strerror(errno));
585: continue;
586: }
587: if (pid != 0) { /* This is the parent. */
588: /* The parent just exits. */
589: exit(0);
590: }
591: /* The child continues serving connections. */
592: continue;
593:
594: case '?':
595: snprintf(buf, sizeof buf,
596: "%c?\r\n\
1.1 deraadt 597: Supported escape sequences:\r\n\
598: ~. - terminate connection\r\n\
599: ~^Z - suspend ssh\r\n\
600: ~# - list forwarded connections\r\n\
601: ~& - background ssh (when waiting for connections to terminate)\r\n\
602: ~? - this message\r\n\
603: ~~ - send the escape character by typing it twice\r\n\
604: (Note that escapes are only recognized immediately after newline.)\r\n",
1.11 markus 605: escape_char);
606: buffer_append(&stderr_buffer, buf, strlen(buf));
607: continue;
608:
609: case '#':
610: snprintf(buf, sizeof buf, "%c#\r\n", escape_char);
611: buffer_append(&stderr_buffer, buf, strlen(buf));
612: s = channel_open_message();
613: buffer_append(&stderr_buffer, s, strlen(s));
614: xfree(s);
615: continue;
616:
617: default:
618: if (ch != escape_char) {
1.13 markus 619: /*
620: * Escape character followed by non-special character.
621: * Append both to the input buffer.
622: */
1.11 markus 623: buf[0] = escape_char;
624: buf[1] = ch;
625: buffer_append(&stdin_buffer, buf, 2);
626: stdin_bytes += 2;
627: continue;
628: }
1.13 markus 629: /*
630: * Note that escape character typed twice
631: * falls through here; the latter gets processed
632: * as a normal character below.
633: */
1.11 markus 634: break;
635: }
636: } else {
1.13 markus 637: /*
638: * The previous character was not an escape char. Check if this
639: * is an escape.
640: */
1.11 markus 641: if (last_was_cr && ch == escape_char) {
642: /* It is. Set the flag and continue to next character. */
643: escape_pending = 1;
644: continue;
645: }
646: }
647:
1.13 markus 648: /*
649: * Normal character. Record whether it was a newline,
650: * and append it to the buffer.
651: */
1.11 markus 652: last_was_cr = (ch == '\r' || ch == '\n');
653: buf[0] = ch;
654: buffer_append(&stdin_buffer, buf, 1);
655: stdin_bytes += 1;
656: continue;
657: }
658: }
659: }
660: }
661:
1.20 markus 662: void
1.11 markus 663: client_process_output(fd_set * writeset)
664: {
665: int len;
666: char buf[100];
1.1 deraadt 667:
1.11 markus 668: /* Write buffered output to stdout. */
669: if (FD_ISSET(fileno(stdout), writeset)) {
670: /* Write as much data as possible. */
671: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 672: buffer_len(&stdout_buffer));
1.11 markus 673: if (len <= 0) {
674: if (errno == EAGAIN)
675: len = 0;
676: else {
1.13 markus 677: /*
678: * An error or EOF was encountered. Put an
679: * error message to stderr buffer.
680: */
1.11 markus 681: snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
682: buffer_append(&stderr_buffer, buf, strlen(buf));
683: stderr_bytes += strlen(buf);
684: quit_pending = 1;
685: return;
686: }
687: }
688: /* Consume printed data from the buffer. */
689: buffer_consume(&stdout_buffer, len);
690: }
691: /* Write buffered output to stderr. */
692: if (FD_ISSET(fileno(stderr), writeset)) {
693: /* Write as much data as possible. */
694: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 695: buffer_len(&stderr_buffer));
1.11 markus 696: if (len <= 0) {
697: if (errno == EAGAIN)
698: len = 0;
699: else {
1.13 markus 700: /* EOF or error, but can't even print error message. */
1.11 markus 701: quit_pending = 1;
702: return;
703: }
704: }
705: /* Consume printed characters from the buffer. */
706: buffer_consume(&stderr_buffer, len);
707: }
1.1 deraadt 708: }
709:
1.13 markus 710: /*
1.15 markus 711: * Get packets from the connection input buffer, and process them as long as
712: * there are packets available.
713: *
714: * Any unknown packets received during the actual
715: * session cause the session to terminate. This is
716: * intended to make debugging easier since no
717: * confirmations are sent. Any compatible protocol
718: * extensions must be negotiated during the
719: * preparatory phase.
720: */
721:
1.20 markus 722: void
1.15 markus 723: client_process_buffered_input_packets()
724: {
725: dispatch_run(DISPATCH_NONBLOCK, &quit_pending);
726: }
727:
1.30 ! markus 728: /* scan stdin buf[] for '~' before sending data to the peer */
! 729:
! 730: int
! 731: simple_escape_filter(Buffer *bin, char *buf, int len)
! 732: {
! 733: unsigned int i;
! 734: unsigned char ch;
! 735: for (i = 0; i < len; i++) {
! 736: ch = buf[i];
! 737: if (escape_pending) {
! 738: escape_pending = 0;
! 739: if (ch == '.') {
! 740: quit_pending = 1;
! 741: return -1;
! 742: }
! 743: if (ch != escape_char)
! 744: buffer_put_char(bin, escape_char);
! 745: } else {
! 746: if (last_was_cr && ch == escape_char) {
! 747: escape_pending = 1;
! 748: continue;
! 749: }
! 750: }
! 751: last_was_cr = (ch == '\n' || ch == '\r');
! 752: buffer_put_char(bin, ch);
! 753: }
! 754: return 0;
! 755: }
! 756:
1.15 markus 757: /*
1.13 markus 758: * Implements the interactive session with the server. This is called after
759: * the user has been authenticated, and a command has been started on the
760: * remote host. If escape_char != -1, it is the character used as an escape
761: * character for terminating or suspending the session.
762: */
1.1 deraadt 763:
1.20 markus 764: int
1.30 ! markus 765: client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1.1 deraadt 766: {
1.11 markus 767: extern Options options;
768: double start_time, total_time;
769: int len;
770: char buf[100];
771:
772: debug("Entering interactive session.");
773:
774: start_time = get_current_time();
775:
776: /* Initialize variables. */
777: escape_pending = 0;
778: last_was_cr = 1;
779: exit_status = -1;
780: stdin_eof = 0;
781: buffer_high = 64 * 1024;
782: connection_in = packet_get_connection_in();
783: connection_out = packet_get_connection_out();
784: max_fd = connection_in;
785: if (connection_out > max_fd)
786: max_fd = connection_out;
787: stdin_bytes = 0;
788: stdout_bytes = 0;
789: stderr_bytes = 0;
790: quit_pending = 0;
791: escape_char = escape_char_arg;
792:
793: /* Initialize buffers. */
794: buffer_init(&stdin_buffer);
795: buffer_init(&stdout_buffer);
796: buffer_init(&stderr_buffer);
797:
1.15 markus 798: client_init_dispatch();
799:
1.11 markus 800: /* Set signal handlers to restore non-blocking mode. */
801: signal(SIGINT, signal_handler);
802: signal(SIGQUIT, signal_handler);
803: signal(SIGTERM, signal_handler);
804: signal(SIGPIPE, SIG_IGN);
805: if (have_pty)
806: signal(SIGWINCH, window_change_handler);
807:
808: if (have_pty)
809: enter_raw_mode();
810:
1.28 provos 811: /* Check if we should immediately send eof on stdin. */
1.17 markus 812: if (!compat20)
1.16 markus 813: client_check_initial_eof_on_stdin();
1.11 markus 814:
1.30 ! markus 815: if (compat20 && escape_char != -1)
! 816: channel_register_filter(ssh2_chan_id, simple_escape_filter);
! 817:
1.11 markus 818: /* Main loop of the client for the interactive session mode. */
819: while (!quit_pending) {
820: fd_set readset, writeset;
821:
1.13 markus 822: /* Process buffered packets sent by the server. */
1.11 markus 823: client_process_buffered_input_packets();
824:
1.16 markus 825: if (compat20 && !channel_still_open()) {
826: debug("!channel_still_open.");
827: break;
828: }
829:
1.13 markus 830: /*
831: * Make packets of buffered stdin data, and buffer them for
832: * sending to the server.
833: */
1.17 markus 834: if (!compat20)
1.16 markus 835: client_make_packets_from_stdin_data();
1.11 markus 836:
1.13 markus 837: /*
838: * Make packets from buffered channel data, and buffer them
839: * for sending to the server.
840: */
1.11 markus 841: if (packet_not_very_much_data_to_write())
842: channel_output_poll();
843:
1.13 markus 844: /*
845: * Check if the window size has changed, and buffer a message
846: * about it to the server if so.
847: */
1.11 markus 848: client_check_window_change();
849:
850: if (quit_pending)
851: break;
852:
1.13 markus 853: /*
854: * Wait until we have something to do (something becomes
855: * available on one of the descriptors).
856: */
1.11 markus 857: client_wait_until_can_do_something(&readset, &writeset);
858:
859: if (quit_pending)
860: break;
861:
862: /* Do channel operations. */
863: channel_after_select(&readset, &writeset);
864:
1.17 markus 865: /* Buffer input from the connection. */
866: client_process_net_input(&readset);
867:
868: if (quit_pending)
869: break;
1.11 markus 870:
1.17 markus 871: if (!compat20) {
872: /* Buffer data from stdin */
873: client_process_input(&readset);
874: /*
875: * Process output to stdout and stderr. Output to
876: * the connection is processed elsewhere (above).
877: */
1.16 markus 878: client_process_output(&writeset);
1.17 markus 879: }
1.11 markus 880:
1.13 markus 881: /* Send as much buffered packet data as possible to the sender. */
1.11 markus 882: if (FD_ISSET(connection_out, &writeset))
883: packet_write_poll();
884: }
885:
886: /* Terminate the session. */
887:
888: /* Stop watching for window change. */
889: if (have_pty)
890: signal(SIGWINCH, SIG_DFL);
891:
892: /* Stop listening for connections. */
893: channel_stop_listening();
894:
1.13 markus 895: /*
896: * In interactive mode (with pseudo tty) display a message indicating
897: * that the connection has been closed.
898: */
1.11 markus 899: if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
900: snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
901: buffer_append(&stderr_buffer, buf, strlen(buf));
902: stderr_bytes += strlen(buf);
903: }
904: /* Output any buffered data for stdout. */
905: while (buffer_len(&stdout_buffer) > 0) {
906: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 907: buffer_len(&stdout_buffer));
1.11 markus 908: if (len <= 0) {
909: error("Write failed flushing stdout buffer.");
910: break;
911: }
912: buffer_consume(&stdout_buffer, len);
913: }
914:
915: /* Output any buffered data for stderr. */
916: while (buffer_len(&stderr_buffer) > 0) {
917: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 918: buffer_len(&stderr_buffer));
1.11 markus 919: if (len <= 0) {
920: error("Write failed flushing stderr buffer.");
921: break;
922: }
923: buffer_consume(&stderr_buffer, len);
924: }
925:
926: if (have_pty)
927: leave_raw_mode();
928:
929: /* Clear and free any buffers. */
930: memset(buf, 0, sizeof(buf));
931: buffer_free(&stdin_buffer);
932: buffer_free(&stdout_buffer);
933: buffer_free(&stderr_buffer);
934:
935: /* Report bytes transferred, and transfer rates. */
936: total_time = get_current_time() - start_time;
937: debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
938: stdin_bytes, stdout_bytes, stderr_bytes, total_time);
939: if (total_time > 0)
940: debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
941: stdin_bytes / total_time, stdout_bytes / total_time,
942: stderr_bytes / total_time);
943:
944: /* Return the exit status of the program. */
945: debug("Exit status %d", exit_status);
946: return exit_status;
1.15 markus 947: }
948:
949: /*********/
950:
951: void
952: client_input_stdout_data(int type, int plen)
953: {
954: unsigned int data_len;
955: char *data = packet_get_string(&data_len);
956: packet_integrity_check(plen, 4 + data_len, type);
957: buffer_append(&stdout_buffer, data, data_len);
958: stdout_bytes += data_len;
959: memset(data, 0, data_len);
960: xfree(data);
961: }
962: void
963: client_input_stderr_data(int type, int plen)
964: {
965: unsigned int data_len;
966: char *data = packet_get_string(&data_len);
967: packet_integrity_check(plen, 4 + data_len, type);
968: buffer_append(&stderr_buffer, data, data_len);
969: stdout_bytes += data_len;
970: memset(data, 0, data_len);
971: xfree(data);
972: }
973: void
974: client_input_exit_status(int type, int plen)
975: {
976: packet_integrity_check(plen, 4, type);
977: exit_status = packet_get_int();
978: /* Acknowledge the exit. */
979: packet_start(SSH_CMSG_EXIT_CONFIRMATION);
980: packet_send();
981: /*
982: * Must wait for packet to be sent since we are
983: * exiting the loop.
984: */
985: packet_write_wait();
986: /* Flag that we want to exit. */
987: quit_pending = 1;
988: }
989:
1.22 markus 990: /* XXXX move to generic input handler */
991: void
992: client_input_channel_open(int type, int plen)
993: {
994: Channel *c = NULL;
995: char *ctype;
996: int id;
997: unsigned int len;
998: int rchan;
999: int rmaxpack;
1000: int rwindow;
1001:
1002: ctype = packet_get_string(&len);
1003: rchan = packet_get_int();
1004: rwindow = packet_get_int();
1005: rmaxpack = packet_get_int();
1006:
1.24 markus 1007: debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1.22 markus 1008: ctype, rchan, rwindow, rmaxpack);
1009:
1010: if (strcmp(ctype, "x11") == 0) {
1011: int sock;
1012: char *originator;
1013: int originator_port;
1014: originator = packet_get_string(NULL);
1.26 markus 1015: if (datafellows & SSH_BUG_X11FWD) {
1.25 markus 1016: debug("buggy server: x11 request w/o originator_port");
1017: originator_port = 0;
1.26 markus 1018: } else {
1019: originator_port = packet_get_int();
1.25 markus 1020: }
1.22 markus 1021: packet_done();
1022: /* XXX check permission */
1023: xfree(originator);
1024: /* XXX move to channels.c */
1025: sock = x11_connect_display();
1026: if (sock >= 0) {
1.30 ! markus 1027: /*XXX MAXPACK */
1.22 markus 1028: id = channel_new("x11", SSH_CHANNEL_X11_OPEN,
1029: sock, sock, -1, 4*1024, 32*1024, 0,
1030: xstrdup("x11"));
1031: c = channel_lookup(id);
1032: }
1033: }
1034: /* XXX duplicate : */
1035: if (c != NULL) {
1036: debug("confirm %s", ctype);
1037: c->remote_id = rchan;
1038: c->remote_window = rwindow;
1039: c->remote_maxpacket = rmaxpack;
1040:
1041: packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1042: packet_put_int(c->remote_id);
1043: packet_put_int(c->self);
1044: packet_put_int(c->local_window);
1045: packet_put_int(c->local_maxpacket);
1046: packet_send();
1047: } else {
1048: debug("failure %s", ctype);
1049: packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1050: packet_put_int(rchan);
1051: packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1052: packet_put_cstring("bla bla");
1053: packet_put_cstring("");
1054: packet_send();
1055: }
1056: xfree(ctype);
1057: }
1058:
1.20 markus 1059: void
1.16 markus 1060: client_init_dispatch_20()
1061: {
1062: dispatch_init(&dispatch_protocol_error);
1063: dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1064: dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1065: dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1066: dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1.22 markus 1067: dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1.16 markus 1068: dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1069: dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1070: dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
1071: dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1072: }
1.20 markus 1073: void
1.15 markus 1074: client_init_dispatch_13()
1075: {
1076: dispatch_init(NULL);
1077: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1078: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1079: dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1080: dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1081: dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1082: dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1083: dispatch_set(SSH_SMSG_AGENT_OPEN, &auth_input_open_request);
1084: dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1085: dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1086: dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1087: dispatch_set(SSH_SMSG_X11_OPEN, &x11_input_open);
1088: }
1.20 markus 1089: void
1.15 markus 1090: client_init_dispatch_15()
1091: {
1092: client_init_dispatch_13();
1093: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1094: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1095: }
1.20 markus 1096: void
1.15 markus 1097: client_init_dispatch()
1098: {
1.16 markus 1099: if (compat20)
1100: client_init_dispatch_20();
1101: else if (compat13)
1.15 markus 1102: client_init_dispatch_13();
1103: else
1104: client_init_dispatch_15();
1.16 markus 1105: }
1106:
1107: void
1108: client_input_channel_req(int id, void *arg)
1109: {
1110: Channel *c = NULL;
1111: unsigned int len;
1112: int success = 0;
1113: int reply;
1114: char *rtype;
1115:
1116: rtype = packet_get_string(&len);
1117: reply = packet_get_char();
1118:
1.23 markus 1119: debug("client_input_channel_req: rtype %s reply %d", rtype, reply);
1.16 markus 1120:
1121: c = channel_lookup(id);
1122: if (c == NULL)
1123: fatal("session_input_channel_req: channel %d: bad channel", id);
1124:
1125: if (session_ident == -1) {
1126: error("client_input_channel_req: no channel %d", id);
1127: } else if (id != session_ident) {
1128: error("client_input_channel_req: bad channel %d != %d",
1129: id, session_ident);
1130: } else if (strcmp(rtype, "exit-status") == 0) {
1131: success = 1;
1132: exit_status = packet_get_int();
1.19 markus 1133: packet_done();
1.16 markus 1134: }
1135: if (reply) {
1136: packet_start(success ?
1137: SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1138: packet_put_int(c->remote_id);
1139: packet_send();
1140: }
1141: xfree(rtype);
1142: }
1143:
1144: void
1145: client_set_session_ident(int id)
1146: {
1147: debug("client_set_session_ident: id %d", id);
1148: session_ident = id;
1149: channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST,
1150: client_input_channel_req, (void *)0);
1.1 deraadt 1151: }
![[BACK]](/icons/back.gif){kind=icon}
Return to clientloop.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh