Annotation of src/usr.bin/ssh/clientloop.c, Revision 1.9
1.1 deraadt 1: /*
2:
3: clientloop.c
4:
5: Author: Tatu Ylonen <ylo@cs.hut.fi>
6:
7: Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: All rights reserved
9:
10:
11: Created: Sat Sep 23 12:23:57 1995 ylo
12:
13: The main loop for the interactive session (client side).
14:
15: */
16:
17: #include "includes.h"
1.9 ! markus 18: RCSID("$Id: clientloop.c,v 1.8 1999/11/10 23:36:43 markus Exp $");
1.1 deraadt 19:
20: #include "xmalloc.h"
21: #include "ssh.h"
22: #include "packet.h"
23: #include "buffer.h"
24: #include "authfd.h"
1.8 markus 25: #include "readconf.h"
1.1 deraadt 26:
27: /* Flag indicating that stdin should be redirected from /dev/null. */
28: extern int stdin_null_flag;
29:
30: /* Name of the host we are connecting to. This is the name given on the
31: command line, or the HostName specified for the user-supplied name
32: in a configuration file. */
33: extern char *host;
34:
35: /* Flag to indicate that we have received a window change signal which has
36: not yet been processed. This will cause a message indicating the new
37: window size to be sent to the server a little later. This is volatile
38: because this is updated in a signal handler. */
39: static volatile int received_window_change_signal = 0;
40:
41: /* Terminal modes, as saved by enter_raw_mode. */
42: static struct termios saved_tio;
43:
44: /* Flag indicating whether we are in raw mode. This is used by enter_raw_mode
45: and leave_raw_mode. */
46: static int in_raw_mode = 0;
47:
48: /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
49: static int in_non_blocking_mode = 0;
50:
51: /* Common data for the client loop code. */
52: static int escape_pending; /* Last character was the escape character */
53: static int last_was_cr; /* Last character was a newline. */
54: static int exit_status; /* Used to store the exit status of the command. */
55: static int stdin_eof; /* EOF has been encountered on standard error. */
56: static Buffer stdin_buffer; /* Buffer for stdin data. */
57: static Buffer stdout_buffer; /* Buffer for stdout data. */
58: static Buffer stderr_buffer; /* Buffer for stderr data. */
59: static unsigned int buffer_high; /* Soft max buffer size. */
60: static int max_fd; /* Maximum file descriptor number in select(). */
61: static int connection_in; /* Connection to server (input). */
62: static int connection_out; /* Connection to server (output). */
63: static unsigned long stdin_bytes, stdout_bytes, stderr_bytes;
64: static int quit_pending; /* Set to non-zero to quit the client loop. */
65: static int escape_char; /* Escape character. */
66:
67: /* Returns the user\'s terminal to normal mode if it had been put in raw
68: mode. */
69:
70: void leave_raw_mode()
71: {
72: if (!in_raw_mode)
73: return;
74: in_raw_mode = 0;
75: if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0)
76: perror("tcsetattr");
77:
78: fatal_remove_cleanup((void (*)(void *))leave_raw_mode, NULL);
79: }
80:
81: /* Puts the user\'s terminal in raw mode. */
82:
83: void enter_raw_mode()
84: {
85: struct termios tio;
86:
87: if (tcgetattr(fileno(stdin), &tio) < 0)
88: perror("tcgetattr");
89: saved_tio = tio;
90: tio.c_iflag |= IGNPAR;
91: tio.c_iflag &= ~(ISTRIP|INLCR|IGNCR|ICRNL|IXON|IXANY|IXOFF);
92: tio.c_lflag &= ~(ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHONL);
93: #ifdef IEXTEN
94: tio.c_lflag &= ~IEXTEN;
95: #endif /* IEXTEN */
96: tio.c_oflag &= ~OPOST;
97: tio.c_cc[VMIN] = 1;
98: tio.c_cc[VTIME] = 0;
99: if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0)
100: perror("tcsetattr");
101: in_raw_mode = 1;
102:
103: fatal_add_cleanup((void (*)(void *))leave_raw_mode, NULL);
104: }
105:
106: /* Puts stdin terminal in non-blocking mode. */
107:
108: /* Restores stdin to blocking mode. */
109:
110: void leave_non_blocking()
111: {
112: if (in_non_blocking_mode)
113: {
114: (void)fcntl(fileno(stdin), F_SETFL, 0);
115: in_non_blocking_mode = 0;
116: fatal_remove_cleanup((void (*)(void *))leave_non_blocking, NULL);
117: }
118: }
119:
120: void enter_non_blocking()
121: {
122: in_non_blocking_mode = 1;
123: (void)fcntl(fileno(stdin), F_SETFL, O_NONBLOCK);
124: fatal_add_cleanup((void (*)(void *))leave_non_blocking, NULL);
125: }
126:
127: /* Signal handler for the window change signal (SIGWINCH). This just
128: sets a flag indicating that the window has changed. */
129:
1.6 deraadt 130: void window_change_handler(int sig)
1.1 deraadt 131: {
132: received_window_change_signal = 1;
133: signal(SIGWINCH, window_change_handler);
134: }
135:
136: /* Signal handler for signals that cause the program to terminate. These
137: signals must be trapped to restore terminal modes. */
138:
1.6 deraadt 139: void signal_handler(int sig)
1.1 deraadt 140: {
141: if (in_raw_mode)
142: leave_raw_mode();
143: if (in_non_blocking_mode)
144: leave_non_blocking();
145: channel_stop_listening();
146: packet_close();
147: fatal("Killed by signal %d.", sig);
148: }
149:
150: /* Returns current time in seconds from Jan 1, 1970 with the maximum available
151: resolution. */
152:
153: double get_current_time()
154: {
155: struct timeval tv;
156: gettimeofday(&tv, NULL);
157: return (double)tv.tv_sec + (double)tv.tv_usec / 1000000.0;
158: }
159:
160: /* This is called when the interactive is entered. This checks if there
161: is an EOF coming on stdin. We must check this explicitly, as select()
162: does not appear to wake up when redirecting from /dev/null. */
163:
164: void client_check_initial_eof_on_stdin()
165: {
166: int len;
167: char buf[1];
168:
169: /* If standard input is to be "redirected from /dev/null", we simply
170: mark that we have seen an EOF and send an EOF message to the server.
171: Otherwise, we try to read a single character; it appears that for some
172: files, such /dev/null, select() never wakes up for read for this
173: descriptor, which means that we never get EOF. This way we will get
174: the EOF if stdin comes from /dev/null or similar. */
175: if (stdin_null_flag)
176: {
177: /* Fake EOF on stdin. */
178: debug("Sending eof.");
179: stdin_eof = 1;
180: packet_start(SSH_CMSG_EOF);
181: packet_send();
182: }
183: else
184: {
185: /* Enter non-blocking mode for stdin. */
186: enter_non_blocking();
187:
188: /* Check for immediate EOF on stdin. */
189: len = read(fileno(stdin), buf, 1);
190: if (len == 0)
191: {
192: /* EOF. Record that we have seen it and send EOF to server. */
193: debug("Sending eof.");
194: stdin_eof = 1;
195: packet_start(SSH_CMSG_EOF);
196: packet_send();
197: }
198: else
199: if (len > 0)
200: {
201: /* Got data. We must store the data in the buffer, and also
202: process it as an escape character if appropriate. */
203: if ((unsigned char)buf[0] == escape_char)
204: escape_pending = 1;
205: else
206: {
207: buffer_append(&stdin_buffer, buf, 1);
208: stdin_bytes += 1;
209: }
210: }
211:
212: /* Leave non-blocking mode. */
213: leave_non_blocking();
214: }
215: }
216:
217: /* Get packets from the connection input buffer, and process them as long
218: as there are packets available. */
219:
220: void client_process_buffered_input_packets()
221: {
222: int type;
223: char *data;
224: unsigned int data_len;
225: int payload_len;
226:
227: /* Process any buffered packets from the server. */
228: while (!quit_pending && (type = packet_read_poll(&payload_len)) != SSH_MSG_NONE)
229: {
230: switch (type)
231: {
232:
233: case SSH_SMSG_STDOUT_DATA:
234: data = packet_get_string(&data_len);
235: packet_integrity_check(payload_len, 4 + data_len, type);
236: buffer_append(&stdout_buffer, data, data_len);
237: stdout_bytes += data_len;
238: memset(data, 0, data_len);
239: xfree(data);
240: break;
241:
242: case SSH_SMSG_STDERR_DATA:
243: data = packet_get_string(&data_len);
244: packet_integrity_check(payload_len, 4 + data_len, type);
245: buffer_append(&stderr_buffer, data, data_len);
246: stdout_bytes += data_len;
247: memset(data, 0, data_len);
248: xfree(data);
249: break;
250:
251: case SSH_SMSG_EXITSTATUS:
252: packet_integrity_check(payload_len, 4, type);
253: exit_status = packet_get_int();
254: /* Acknowledge the exit. */
255: packet_start(SSH_CMSG_EXIT_CONFIRMATION);
256: packet_send();
257: /* Must wait for packet to be sent since we are exiting the
258: loop. */
259: packet_write_wait();
260: /* Flag that we want to exit. */
261: quit_pending = 1;
262: break;
263:
264: case SSH_SMSG_X11_OPEN:
265: x11_input_open(payload_len);
266: break;
267:
268: case SSH_MSG_PORT_OPEN:
269: channel_input_port_open(payload_len);
270: break;
271:
272: case SSH_SMSG_AGENT_OPEN:
273: packet_integrity_check(payload_len, 4, type);
274: auth_input_open_request();
275: break;
276:
277: case SSH_MSG_CHANNEL_OPEN_CONFIRMATION:
278: packet_integrity_check(payload_len, 4 + 4, type);
279: channel_input_open_confirmation();
280: break;
281:
282: case SSH_MSG_CHANNEL_OPEN_FAILURE:
283: packet_integrity_check(payload_len, 4, type);
284: channel_input_open_failure();
285: break;
286:
287: case SSH_MSG_CHANNEL_DATA:
288: channel_input_data(payload_len);
289: break;
290:
291: case SSH_MSG_CHANNEL_CLOSE:
292: packet_integrity_check(payload_len, 4, type);
293: channel_input_close();
294: break;
295:
296: case SSH_MSG_CHANNEL_CLOSE_CONFIRMATION:
297: packet_integrity_check(payload_len, 4, type);
298: channel_input_close_confirmation();
299: break;
300:
301: default:
302: /* Any unknown packets received during the actual session
303: cause the session to terminate. This is intended to make
304: debugging easier since no confirmations are sent. Any
305: compatible protocol extensions must be negotiated during
306: the preparatory phase. */
307: packet_disconnect("Protocol error during session: type %d",
308: type);
309: }
310: }
311: }
312:
313: /* Make packets from buffered stdin data, and buffer them for sending to
314: the connection. */
315:
316: void client_make_packets_from_stdin_data()
317: {
318: unsigned int len;
319:
320: /* Send buffered stdin data to the server. */
321: while (buffer_len(&stdin_buffer) > 0 &&
322: packet_not_very_much_data_to_write())
323: {
324: len = buffer_len(&stdin_buffer);
325: if (len > 32768)
326: len = 32768; /* Keep the packets at reasonable size. */
327: packet_start(SSH_CMSG_STDIN_DATA);
328: packet_put_string(buffer_ptr(&stdin_buffer), len);
329: packet_send();
330: buffer_consume(&stdin_buffer, len);
331: /* If we have a pending EOF, send it now. */
332: if (stdin_eof && buffer_len(&stdin_buffer) == 0)
333: {
334: packet_start(SSH_CMSG_EOF);
335: packet_send();
336: }
337: }
338: }
339:
340: /* Checks if the client window has changed, and sends a packet about it to
341: the server if so. The actual change is detected elsewhere (by a software
342: interrupt on Unix); this just checks the flag and sends a message if
343: appropriate. */
344:
345: void client_check_window_change()
346: {
347: /* Send possible window change message to the server. */
348: if (received_window_change_signal)
349: {
350: struct winsize ws;
351:
352: /* Clear the window change indicator. */
353: received_window_change_signal = 0;
354:
355: /* Read new window size. */
356: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) >= 0)
357: {
358: /* Successful, send the packet now. */
359: packet_start(SSH_CMSG_WINDOW_SIZE);
360: packet_put_int(ws.ws_row);
361: packet_put_int(ws.ws_col);
362: packet_put_int(ws.ws_xpixel);
363: packet_put_int(ws.ws_ypixel);
364: packet_send();
365: }
366: }
367: }
368:
369: /* Waits until the client can do something (some data becomes available on
370: one of the file descriptors). */
371:
372: void client_wait_until_can_do_something(fd_set *readset, fd_set *writeset)
373: {
374: /* Initialize select masks. */
375: FD_ZERO(readset);
376:
377: /* Read from the connection, unless our buffers are full. */
378: if (buffer_len(&stdout_buffer) < buffer_high &&
379: buffer_len(&stderr_buffer) < buffer_high &&
380: channel_not_very_much_buffered_data())
381: FD_SET(connection_in, readset);
382:
383: /* Read from stdin, unless we have seen EOF or have very much buffered
384: data to send to the server. */
385: if (!stdin_eof && packet_not_very_much_data_to_write())
386: FD_SET(fileno(stdin), readset);
387:
388: FD_ZERO(writeset);
389:
390: /* Add any selections by the channel mechanism. */
391: channel_prepare_select(readset, writeset);
392:
393: /* Select server connection if have data to write to the server. */
394: if (packet_have_data_to_write())
395: FD_SET(connection_out, writeset);
396:
397: /* Select stdout if have data in buffer. */
398: if (buffer_len(&stdout_buffer) > 0)
399: FD_SET(fileno(stdout), writeset);
400:
401: /* Select stderr if have data in buffer. */
402: if (buffer_len(&stderr_buffer) > 0)
403: FD_SET(fileno(stderr), writeset);
404:
405: /* Update maximum file descriptor number, if appropriate. */
406: if (channel_max_fd() > max_fd)
407: max_fd = channel_max_fd();
408:
409: /* Wait for something to happen. This will suspend the process until
410: some selected descriptor can be read, written, or has some other
411: event pending. Note: if you want to implement SSH_MSG_IGNORE
412: messages to fool traffic analysis, this might be the place to do
413: it: just have a random timeout for the select, and send a random
414: SSH_MSG_IGNORE packet when the timeout expires. */
415: if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0)
416: {
417: char buf[100];
418: /* Some systems fail to clear these automatically. */
419: FD_ZERO(readset);
420: FD_ZERO(writeset);
421: if (errno == EINTR)
422: return;
423: /* Note: we might still have data in the buffers. */
1.7 deraadt 424: snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
1.1 deraadt 425: buffer_append(&stderr_buffer, buf, strlen(buf));
426: stderr_bytes += strlen(buf);
427: quit_pending = 1;
428: }
429: }
430:
431: void client_suspend_self()
432: {
433: struct winsize oldws, newws;
434:
435: /* Flush stdout and stderr buffers. */
436: if (buffer_len(&stdout_buffer) > 0)
437: write(fileno(stdout),
438: buffer_ptr(&stdout_buffer),
439: buffer_len(&stdout_buffer));
440: if (buffer_len(&stderr_buffer) > 0)
441: write(fileno(stderr),
442: buffer_ptr(&stderr_buffer),
443: buffer_len(&stderr_buffer));
444:
445: /* Leave raw mode. */
446: leave_raw_mode();
447:
448: /* Free (and clear) the buffer to reduce the
449: amount of data that gets written to swap. */
450: buffer_free(&stdin_buffer);
451: buffer_free(&stdout_buffer);
452: buffer_free(&stderr_buffer);
453:
454: /* Save old window size. */
455: ioctl(fileno(stdin), TIOCGWINSZ, &oldws);
456:
457: /* Send the suspend signal to the program
458: itself. */
459: kill(getpid(), SIGTSTP);
460:
461: /* Check if the window size has changed. */
462: if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 &&
463: (oldws.ws_row != newws.ws_row || oldws.ws_col != newws.ws_col ||
464: oldws.ws_xpixel != newws.ws_xpixel ||
465: oldws.ws_ypixel != newws.ws_ypixel))
466: received_window_change_signal = 1;
467:
468: /* OK, we have been continued by the user.
469: Reinitialize buffers. */
470: buffer_init(&stdin_buffer);
471: buffer_init(&stdout_buffer);
472: buffer_init(&stderr_buffer);
473:
474: /* Re-enter raw mode. */
475: enter_raw_mode();
476: }
477:
478: void client_process_input(fd_set *readset)
479: {
480: int len, pid;
481: char buf[8192], *s;
482:
483: /* Read input from the server, and add any such data to the buffer of the
484: packet subsystem. */
485: if (FD_ISSET(connection_in, readset))
486: {
487: /* Read as much as possible. */
488: len = read(connection_in, buf, sizeof(buf));
489: if (len == 0)
490: {
491: /* Received EOF. The remote host has closed the connection. */
1.7 deraadt 492: snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
1.1 deraadt 493: host);
494: buffer_append(&stderr_buffer, buf, strlen(buf));
495: stderr_bytes += strlen(buf);
496: quit_pending = 1;
497: return;
498: }
499:
500: /* There is a kernel bug on Solaris that causes select to sometimes
501: wake up even though there is no data available. */
502: if (len < 0 && errno == EAGAIN)
503: len = 0;
504:
505: if (len < 0)
506: {
507: /* An error has encountered. Perhaps there is a network
508: problem. */
1.7 deraadt 509: snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
1.1 deraadt 510: host, strerror(errno));
511: buffer_append(&stderr_buffer, buf, strlen(buf));
512: stderr_bytes += strlen(buf);
513: quit_pending = 1;
514: return;
515: }
516: packet_process_incoming(buf, len);
517: }
518:
519: /* Read input from stdin. */
520: if (FD_ISSET(fileno(stdin), readset))
521: {
522: /* Read as much as possible. */
523: len = read(fileno(stdin), buf, sizeof(buf));
524: if (len <= 0)
525: {
526: /* Received EOF or error. They are treated similarly,
527: except that an error message is printed if it was
528: an error condition. */
529: if (len < 0)
530: {
1.7 deraadt 531: snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
1.1 deraadt 532: buffer_append(&stderr_buffer, buf, strlen(buf));
533: stderr_bytes += strlen(buf);
534: }
535: /* Mark that we have seen EOF. */
536: stdin_eof = 1;
537: /* Send an EOF message to the server unless there is data
538: in the buffer. If there is data in the buffer, no message
539: will be sent now. Code elsewhere will send the EOF
540: when the buffer becomes empty if stdin_eof is set. */
541: if (buffer_len(&stdin_buffer) == 0)
542: {
543: packet_start(SSH_CMSG_EOF);
544: packet_send();
545: }
546: }
547: else
548: if (escape_char == -1)
549: {
550: /* Normal successful read, and no escape character. Just
551: append the data to buffer. */
552: buffer_append(&stdin_buffer, buf, len);
553: stdin_bytes += len;
554: }
555: else
556: {
557: /* Normal, successful read. But we have an escape character
558: and have to process the characters one by one. */
559: unsigned int i;
560: for (i = 0; i < len; i++)
561: {
562: unsigned char ch;
563: /* Get one character at a time. */
564: ch = buf[i];
565:
566: /* Check if we have a pending escape character. */
567: if (escape_pending)
568: {
569: /* We have previously seen an escape character. */
570: /* Clear the flag now. */
571: escape_pending = 0;
572: /* Process the escaped character. */
573: switch (ch)
574: {
575: case '.':
576: /* Terminate the connection. */
1.7 deraadt 577: snprintf(buf, sizeof buf, "%c.\r\n", escape_char);
1.1 deraadt 578: buffer_append(&stderr_buffer, buf, strlen(buf));
579: stderr_bytes += strlen(buf);
580: quit_pending = 1;
581: return;
582:
583: case 'Z' - 64:
584: /* Suspend the program. */
585: /* Print a message to that effect to the user. */
1.7 deraadt 586: snprintf(buf, sizeof buf, "%c^Z\r\n", escape_char);
1.1 deraadt 587: buffer_append(&stderr_buffer, buf, strlen(buf));
588: stderr_bytes += strlen(buf);
589:
590: /* Restore terminal modes and suspend. */
591: client_suspend_self();
592:
593: /* We have been continued. */
594: continue;
595:
596: case '&':
597: /* Detach the program (continue to serve connections,
598: but put in background and no more new
599: connections). */
600: if (!stdin_eof)
601: {
602: /* Sending SSH_CMSG_EOF alone does not always
603: appear to be enough. So we try to send an
604: EOF character first. */
605: packet_start(SSH_CMSG_STDIN_DATA);
606: packet_put_string("\004", 1);
607: packet_send();
608: /* Close stdin. */
609: stdin_eof = 1;
610: if (buffer_len(&stdin_buffer) == 0)
611: {
612: packet_start(SSH_CMSG_EOF);
613: packet_send();
614: }
615: }
616: /* Restore tty modes. */
617: leave_raw_mode();
618:
619: /* Stop listening for new connections. */
620: channel_stop_listening();
621:
622: printf("%c& [backgrounded]\n", escape_char);
623:
624: /* Fork into background. */
625: pid = fork();
626: if (pid < 0)
627: {
628: error("fork: %.100s", strerror(errno));
629: continue;
630: }
631: if (pid != 0)
632: { /* This is the parent. */
633: /* The parent just exits. */
634: exit(0);
635: }
636:
637: /* The child continues serving connections. */
638: continue;
639:
640: case '?':
1.7 deraadt 641: snprintf(buf, sizeof buf, "%c?\r\n\
1.1 deraadt 642: Supported escape sequences:\r\n\
643: ~. - terminate connection\r\n\
644: ~^Z - suspend ssh\r\n\
645: ~# - list forwarded connections\r\n\
646: ~& - background ssh (when waiting for connections to terminate)\r\n\
647: ~? - this message\r\n\
648: ~~ - send the escape character by typing it twice\r\n\
649: (Note that escapes are only recognized immediately after newline.)\r\n",
650: escape_char);
651: buffer_append(&stderr_buffer, buf, strlen(buf));
652: continue;
653:
654: case '#':
1.7 deraadt 655: snprintf(buf, sizeof buf, "%c#\r\n", escape_char);
1.1 deraadt 656: buffer_append(&stderr_buffer, buf, strlen(buf));
657: s = channel_open_message();
658: buffer_append(&stderr_buffer, s, strlen(s));
659: xfree(s);
660: continue;
661:
662: default:
663: if (ch != escape_char)
664: {
665: /* Escape character followed by non-special
666: character. Append both to the input
667: buffer. */
668: buf[0] = escape_char;
669: buf[1] = ch;
670: buffer_append(&stdin_buffer, buf, 2);
671: stdin_bytes += 2;
672: continue;
673: }
674: /* Note that escape character typed twice falls through
675: here; the latter gets processed as a normal
676: character below. */
677: break;
678: }
679: }
680: else
681: {
682: /* The previous character was not an escape char.
683: Check if this is an escape. */
684: if (last_was_cr && ch == escape_char)
685: {
686: /* It is. Set the flag and continue to next
687: character. */
688: escape_pending = 1;
689: continue;
690: }
691: }
692:
693: /* Normal character. Record whether it was a newline,
694: and append it to the buffer. */
695: last_was_cr = (ch == '\r' || ch == '\n');
696: buf[0] = ch;
697: buffer_append(&stdin_buffer, buf, 1);
698: stdin_bytes += 1;
699: continue;
700: }
701: }
702: }
703: }
704:
705: void client_process_output(fd_set *writeset)
706: {
707: int len;
708: char buf[100];
709:
710: /* Write buffered output to stdout. */
711: if (FD_ISSET(fileno(stdout), writeset))
712: {
713: /* Write as much data as possible. */
714: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
715: buffer_len(&stdout_buffer));
716: if (len <= 0)
717: {
718: if (errno == EAGAIN)
719: len = 0;
720: else
721: {
722: /* An error or EOF was encountered. Put an error message
723: to stderr buffer. */
1.7 deraadt 724: snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
1.1 deraadt 725: buffer_append(&stderr_buffer, buf, strlen(buf));
726: stderr_bytes += strlen(buf);
727: quit_pending = 1;
728: return;
729: }
730: }
731: /* Consume printed data from the buffer. */
732: buffer_consume(&stdout_buffer, len);
733: }
734:
735: /* Write buffered output to stderr. */
736: if (FD_ISSET(fileno(stderr), writeset))
737: {
738: /* Write as much data as possible. */
739: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
740: buffer_len(&stderr_buffer));
1.2 provos 741: if (len <= 0) {
1.1 deraadt 742: if (errno == EAGAIN)
743: len = 0;
744: else
745: {
746: /* EOF or error, but can't even print error message. */
747: quit_pending = 1;
748: return;
749: }
1.2 provos 750: }
1.1 deraadt 751: /* Consume printed characters from the buffer. */
752: buffer_consume(&stderr_buffer, len);
753: }
754: }
755:
756: /* Implements the interactive session with the server. This is called
757: after the user has been authenticated, and a command has been
758: started on the remote host. If escape_char != -1, it is the character
759: used as an escape character for terminating or suspending the
760: session. */
761:
762: int client_loop(int have_pty, int escape_char_arg)
763: {
1.9 ! markus 764: extern Options options;
1.1 deraadt 765: double start_time, total_time;
766: int len;
767: char buf[100];
768:
769: debug("Entering interactive session.");
770:
771: start_time = get_current_time();
772:
773: /* Initialize variables. */
774: escape_pending = 0;
775: last_was_cr = 1;
776: exit_status = -1;
777: stdin_eof = 0;
778: buffer_high = 64 * 1024;
779: connection_in = packet_get_connection_in();
780: connection_out = packet_get_connection_out();
781: max_fd = connection_in;
782: if (connection_out > max_fd)
783: max_fd = connection_out;
784: stdin_bytes = 0;
785: stdout_bytes = 0;
786: stderr_bytes = 0;
787: quit_pending = 0;
788: escape_char = escape_char_arg;
789:
790: /* Initialize buffers. */
791: buffer_init(&stdin_buffer);
792: buffer_init(&stdout_buffer);
793: buffer_init(&stderr_buffer);
794:
795: /* Set signal handlers to restore non-blocking mode. */
796: signal(SIGINT, signal_handler);
797: signal(SIGQUIT, signal_handler);
798: signal(SIGTERM, signal_handler);
799: signal(SIGPIPE, SIG_IGN);
800: if (have_pty)
801: signal(SIGWINCH, window_change_handler);
802:
803: /* Enter raw mode if have a pseudo terminal. */
804: if (have_pty)
805: enter_raw_mode();
806:
807: /* Check if we should immediately send of on stdin. */
808: client_check_initial_eof_on_stdin();
809:
810: /* Main loop of the client for the interactive session mode. */
811: while (!quit_pending)
812: {
813: fd_set readset, writeset;
814:
815: /* Precess buffered packets sent by the server. */
816: client_process_buffered_input_packets();
817:
818: /* Make packets of buffered stdin data, and buffer them for sending
819: to the server. */
820: client_make_packets_from_stdin_data();
821:
822: /* Make packets from buffered channel data, and buffer them for sending
823: to the server. */
824: if (packet_not_very_much_data_to_write())
825: channel_output_poll();
826:
827: /* Check if the window size has changed, and buffer a message about
828: it to the server if so. */
829: client_check_window_change();
830:
831: if (quit_pending)
832: break;
833:
834: /* Wait until we have something to do (something becomes available
835: on one of the descriptors). */
836: client_wait_until_can_do_something(&readset, &writeset);
837:
838: if (quit_pending)
839: break;
840:
841: /* Do channel operations. */
842: channel_after_select(&readset, &writeset);
843:
844: /* Process input from the connection and from stdin. Buffer any data
845: that is available. */
846: client_process_input(&readset);
847:
848: /* Process output to stdout and stderr. Output to the connection
849: is processed elsewhere (above). */
850: client_process_output(&writeset);
851:
852: /* Send as much buffered packet data as possible to the sender. */
853: if (FD_ISSET(connection_out, &writeset))
854: packet_write_poll();
855: }
856:
857: /* Terminate the session. */
858:
859: /* Stop watching for window change. */
860: if (have_pty)
861: signal(SIGWINCH, SIG_DFL);
862:
863: /* Stop listening for connections. */
864: channel_stop_listening();
865:
866: /* In interactive mode (with pseudo tty) display a message indicating that
867: the connection has been closed. */
1.8 markus 868: if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET)
1.1 deraadt 869: {
1.7 deraadt 870: snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
1.1 deraadt 871: buffer_append(&stderr_buffer, buf, strlen(buf));
872: stderr_bytes += strlen(buf);
873: }
874:
875: /* Output any buffered data for stdout. */
876: while (buffer_len(&stdout_buffer) > 0)
877: {
878: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
879: buffer_len(&stdout_buffer));
880: if (len <= 0)
881: {
882: error("Write failed flushing stdout buffer.");
883: break;
884: }
885: buffer_consume(&stdout_buffer, len);
886: }
887:
888: /* Output any buffered data for stderr. */
889: while (buffer_len(&stderr_buffer) > 0)
890: {
891: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
892: buffer_len(&stderr_buffer));
893: if (len <= 0)
894: {
895: error("Write failed flushing stderr buffer.");
896: break;
897: }
898: buffer_consume(&stderr_buffer, len);
899: }
900:
901: /* Leave raw mode. */
902: if (have_pty)
903: leave_raw_mode();
904:
905: /* Clear and free any buffers. */
906: memset(buf, 0, sizeof(buf));
907: buffer_free(&stdin_buffer);
908: buffer_free(&stdout_buffer);
909: buffer_free(&stderr_buffer);
910:
911: /* Report bytes transferred, and transfer rates. */
912: total_time = get_current_time() - start_time;
913: debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
914: stdin_bytes, stdout_bytes, stderr_bytes, total_time);
915: if (total_time > 0)
916: debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
917: stdin_bytes / total_time, stdout_bytes / total_time,
918: stderr_bytes / total_time);
919:
920: /* Return the exit status of the program. */
921: debug("Exit status %d", exit_status);
922: return exit_status;
923: }
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