Annotation of src/usr.bin/ssh/clientloop.c, Revision 1.4
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"
1.4 ! deraadt 18: RCSID("$Id: clientloop.c,v 1.3 1999/09/30 05:03:04 deraadt 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"
25:
26: /* Flag indicating whether quiet mode is on. */
27: extern int quiet_flag;
28:
29: /* Flag indicating that stdin should be redirected from /dev/null. */
30: extern int stdin_null_flag;
31:
32: /* Name of the host we are connecting to. This is the name given on the
33: command line, or the HostName specified for the user-supplied name
34: in a configuration file. */
35: extern char *host;
36:
37: #ifdef SIGWINCH
38: /* Flag to indicate that we have received a window change signal which has
39: not yet been processed. This will cause a message indicating the new
40: window size to be sent to the server a little later. This is volatile
41: because this is updated in a signal handler. */
42: static volatile int received_window_change_signal = 0;
43: #endif /* SIGWINCH */
44:
45: /* Terminal modes, as saved by enter_raw_mode. */
46: static struct termios saved_tio;
47:
48: /* Flag indicating whether we are in raw mode. This is used by enter_raw_mode
49: and leave_raw_mode. */
50: static int in_raw_mode = 0;
51:
52: /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
53: static int in_non_blocking_mode = 0;
54:
55: /* Common data for the client loop code. */
56: static int escape_pending; /* Last character was the escape character */
57: static int last_was_cr; /* Last character was a newline. */
58: static int exit_status; /* Used to store the exit status of the command. */
59: static int stdin_eof; /* EOF has been encountered on standard error. */
60: static Buffer stdin_buffer; /* Buffer for stdin data. */
61: static Buffer stdout_buffer; /* Buffer for stdout data. */
62: static Buffer stderr_buffer; /* Buffer for stderr data. */
63: static unsigned int buffer_high; /* Soft max buffer size. */
64: static int max_fd; /* Maximum file descriptor number in select(). */
65: static int connection_in; /* Connection to server (input). */
66: static int connection_out; /* Connection to server (output). */
67: static unsigned long stdin_bytes, stdout_bytes, stderr_bytes;
68: static int quit_pending; /* Set to non-zero to quit the client loop. */
69: static int escape_char; /* Escape character. */
70:
71: /* Returns the user\'s terminal to normal mode if it had been put in raw
72: mode. */
73:
74: void leave_raw_mode()
75: {
76: if (!in_raw_mode)
77: return;
78: in_raw_mode = 0;
79: if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0)
80: perror("tcsetattr");
81:
82: fatal_remove_cleanup((void (*)(void *))leave_raw_mode, NULL);
83: }
84:
85: /* Puts the user\'s terminal in raw mode. */
86:
87: void enter_raw_mode()
88: {
89: struct termios tio;
90:
91: if (tcgetattr(fileno(stdin), &tio) < 0)
92: perror("tcgetattr");
93: saved_tio = tio;
94: tio.c_iflag |= IGNPAR;
95: tio.c_iflag &= ~(ISTRIP|INLCR|IGNCR|ICRNL|IXON|IXANY|IXOFF);
96: tio.c_lflag &= ~(ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHONL);
97: #ifdef IEXTEN
98: tio.c_lflag &= ~IEXTEN;
99: #endif /* IEXTEN */
100: tio.c_oflag &= ~OPOST;
101: tio.c_cc[VMIN] = 1;
102: tio.c_cc[VTIME] = 0;
103: if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0)
104: perror("tcsetattr");
105: in_raw_mode = 1;
106:
107: fatal_add_cleanup((void (*)(void *))leave_raw_mode, NULL);
108: }
109:
110: /* Puts stdin terminal in non-blocking mode. */
111:
112: /* Restores stdin to blocking mode. */
113:
114: void leave_non_blocking()
115: {
116: if (in_non_blocking_mode)
117: {
118: (void)fcntl(fileno(stdin), F_SETFL, 0);
119: in_non_blocking_mode = 0;
120: fatal_remove_cleanup((void (*)(void *))leave_non_blocking, NULL);
121: }
122: }
123:
124: void enter_non_blocking()
125: {
126: in_non_blocking_mode = 1;
127: (void)fcntl(fileno(stdin), F_SETFL, O_NONBLOCK);
128: fatal_add_cleanup((void (*)(void *))leave_non_blocking, NULL);
129: }
130:
131: #ifdef SIGWINCH
132: /* Signal handler for the window change signal (SIGWINCH). This just
133: sets a flag indicating that the window has changed. */
134:
135: RETSIGTYPE window_change_handler(int sig)
136: {
137: received_window_change_signal = 1;
138: signal(SIGWINCH, window_change_handler);
139: }
140: #endif /* SIGWINCH */
141:
142: /* Signal handler for signals that cause the program to terminate. These
143: signals must be trapped to restore terminal modes. */
144:
145: RETSIGTYPE signal_handler(int sig)
146: {
147: if (in_raw_mode)
148: leave_raw_mode();
149: if (in_non_blocking_mode)
150: leave_non_blocking();
151: channel_stop_listening();
152: packet_close();
153: fatal("Killed by signal %d.", sig);
154: }
155:
156: /* Returns current time in seconds from Jan 1, 1970 with the maximum available
157: resolution. */
158:
159: double get_current_time()
160: {
161: struct timeval tv;
162: gettimeofday(&tv, NULL);
163: return (double)tv.tv_sec + (double)tv.tv_usec / 1000000.0;
164: }
165:
166: /* This is called when the interactive is entered. This checks if there
167: is an EOF coming on stdin. We must check this explicitly, as select()
168: does not appear to wake up when redirecting from /dev/null. */
169:
170: void client_check_initial_eof_on_stdin()
171: {
172: int len;
173: char buf[1];
174:
175: /* If standard input is to be "redirected from /dev/null", we simply
176: mark that we have seen an EOF and send an EOF message to the server.
177: Otherwise, we try to read a single character; it appears that for some
178: files, such /dev/null, select() never wakes up for read for this
179: descriptor, which means that we never get EOF. This way we will get
180: the EOF if stdin comes from /dev/null or similar. */
181: if (stdin_null_flag)
182: {
183: /* Fake EOF on stdin. */
184: debug("Sending eof.");
185: stdin_eof = 1;
186: packet_start(SSH_CMSG_EOF);
187: packet_send();
188: }
189: else
190: {
191: /* Enter non-blocking mode for stdin. */
192: enter_non_blocking();
193:
194: /* Check for immediate EOF on stdin. */
195: len = read(fileno(stdin), buf, 1);
196: if (len == 0)
197: {
198: /* EOF. Record that we have seen it and send EOF to server. */
199: debug("Sending eof.");
200: stdin_eof = 1;
201: packet_start(SSH_CMSG_EOF);
202: packet_send();
203: }
204: else
205: if (len > 0)
206: {
207: /* Got data. We must store the data in the buffer, and also
208: process it as an escape character if appropriate. */
209: if ((unsigned char)buf[0] == escape_char)
210: escape_pending = 1;
211: else
212: {
213: buffer_append(&stdin_buffer, buf, 1);
214: stdin_bytes += 1;
215: }
216: }
217:
218: /* Leave non-blocking mode. */
219: leave_non_blocking();
220: }
221: }
222:
223: /* Get packets from the connection input buffer, and process them as long
224: as there are packets available. */
225:
226: void client_process_buffered_input_packets()
227: {
228: int type;
229: char *data;
230: unsigned int data_len;
231: int payload_len;
232:
233: /* Process any buffered packets from the server. */
234: while (!quit_pending && (type = packet_read_poll(&payload_len)) != SSH_MSG_NONE)
235: {
236: switch (type)
237: {
238:
239: case SSH_SMSG_STDOUT_DATA:
240: data = packet_get_string(&data_len);
241: packet_integrity_check(payload_len, 4 + data_len, type);
242: buffer_append(&stdout_buffer, data, data_len);
243: stdout_bytes += data_len;
244: memset(data, 0, data_len);
245: xfree(data);
246: break;
247:
248: case SSH_SMSG_STDERR_DATA:
249: data = packet_get_string(&data_len);
250: packet_integrity_check(payload_len, 4 + data_len, type);
251: buffer_append(&stderr_buffer, data, data_len);
252: stdout_bytes += data_len;
253: memset(data, 0, data_len);
254: xfree(data);
255: break;
256:
257: case SSH_SMSG_EXITSTATUS:
258: packet_integrity_check(payload_len, 4, type);
259: exit_status = packet_get_int();
260: /* Acknowledge the exit. */
261: packet_start(SSH_CMSG_EXIT_CONFIRMATION);
262: packet_send();
263: /* Must wait for packet to be sent since we are exiting the
264: loop. */
265: packet_write_wait();
266: /* Flag that we want to exit. */
267: quit_pending = 1;
268: break;
269:
270: case SSH_SMSG_X11_OPEN:
271: x11_input_open(payload_len);
272: break;
273:
274: case SSH_MSG_PORT_OPEN:
275: channel_input_port_open(payload_len);
276: break;
277:
278: case SSH_SMSG_AGENT_OPEN:
279: packet_integrity_check(payload_len, 4, type);
280: auth_input_open_request();
281: break;
282:
283: case SSH_MSG_CHANNEL_OPEN_CONFIRMATION:
284: packet_integrity_check(payload_len, 4 + 4, type);
285: channel_input_open_confirmation();
286: break;
287:
288: case SSH_MSG_CHANNEL_OPEN_FAILURE:
289: packet_integrity_check(payload_len, 4, type);
290: channel_input_open_failure();
291: break;
292:
293: case SSH_MSG_CHANNEL_DATA:
294: channel_input_data(payload_len);
295: break;
296:
297: case SSH_MSG_CHANNEL_CLOSE:
298: packet_integrity_check(payload_len, 4, type);
299: channel_input_close();
300: break;
301:
302: case SSH_MSG_CHANNEL_CLOSE_CONFIRMATION:
303: packet_integrity_check(payload_len, 4, type);
304: channel_input_close_confirmation();
305: break;
306:
307: default:
308: /* Any unknown packets received during the actual session
309: cause the session to terminate. This is intended to make
310: debugging easier since no confirmations are sent. Any
311: compatible protocol extensions must be negotiated during
312: the preparatory phase. */
313: packet_disconnect("Protocol error during session: type %d",
314: type);
315: }
316: }
317: }
318:
319: /* Make packets from buffered stdin data, and buffer them for sending to
320: the connection. */
321:
322: void client_make_packets_from_stdin_data()
323: {
324: unsigned int len;
325:
326: /* Send buffered stdin data to the server. */
327: while (buffer_len(&stdin_buffer) > 0 &&
328: packet_not_very_much_data_to_write())
329: {
330: len = buffer_len(&stdin_buffer);
331: if (len > 32768)
332: len = 32768; /* Keep the packets at reasonable size. */
333: packet_start(SSH_CMSG_STDIN_DATA);
334: packet_put_string(buffer_ptr(&stdin_buffer), len);
335: packet_send();
336: buffer_consume(&stdin_buffer, len);
337: /* If we have a pending EOF, send it now. */
338: if (stdin_eof && buffer_len(&stdin_buffer) == 0)
339: {
340: packet_start(SSH_CMSG_EOF);
341: packet_send();
342: }
343: }
344: }
345:
346: /* Checks if the client window has changed, and sends a packet about it to
347: the server if so. The actual change is detected elsewhere (by a software
348: interrupt on Unix); this just checks the flag and sends a message if
349: appropriate. */
350:
351: void client_check_window_change()
352: {
353: #ifdef SIGWINCH
354: /* Send possible window change message to the server. */
355: if (received_window_change_signal)
356: {
357: struct winsize ws;
358:
359: /* Clear the window change indicator. */
360: received_window_change_signal = 0;
361:
362: /* Read new window size. */
363: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) >= 0)
364: {
365: /* Successful, send the packet now. */
366: packet_start(SSH_CMSG_WINDOW_SIZE);
367: packet_put_int(ws.ws_row);
368: packet_put_int(ws.ws_col);
369: packet_put_int(ws.ws_xpixel);
370: packet_put_int(ws.ws_ypixel);
371: packet_send();
372: }
373: }
374: #endif /* SIGWINCH */
375: }
376:
377: /* Waits until the client can do something (some data becomes available on
378: one of the file descriptors). */
379:
380: void client_wait_until_can_do_something(fd_set *readset, fd_set *writeset)
381: {
382: /* Initialize select masks. */
383: FD_ZERO(readset);
384:
385: /* Read from the connection, unless our buffers are full. */
386: if (buffer_len(&stdout_buffer) < buffer_high &&
387: buffer_len(&stderr_buffer) < buffer_high &&
388: channel_not_very_much_buffered_data())
389: FD_SET(connection_in, readset);
390:
391: /* Read from stdin, unless we have seen EOF or have very much buffered
392: data to send to the server. */
393: if (!stdin_eof && packet_not_very_much_data_to_write())
394: FD_SET(fileno(stdin), readset);
395:
396: FD_ZERO(writeset);
397:
398: /* Add any selections by the channel mechanism. */
399: channel_prepare_select(readset, writeset);
400:
401: /* Select server connection if have data to write to the server. */
402: if (packet_have_data_to_write())
403: FD_SET(connection_out, writeset);
404:
405: /* Select stdout if have data in buffer. */
406: if (buffer_len(&stdout_buffer) > 0)
407: FD_SET(fileno(stdout), writeset);
408:
409: /* Select stderr if have data in buffer. */
410: if (buffer_len(&stderr_buffer) > 0)
411: FD_SET(fileno(stderr), writeset);
412:
413: /* Update maximum file descriptor number, if appropriate. */
414: if (channel_max_fd() > max_fd)
415: max_fd = channel_max_fd();
416:
417: /* Wait for something to happen. This will suspend the process until
418: some selected descriptor can be read, written, or has some other
419: event pending. Note: if you want to implement SSH_MSG_IGNORE
420: messages to fool traffic analysis, this might be the place to do
421: it: just have a random timeout for the select, and send a random
422: SSH_MSG_IGNORE packet when the timeout expires. */
423: if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0)
424: {
425: char buf[100];
426: /* Some systems fail to clear these automatically. */
427: FD_ZERO(readset);
428: FD_ZERO(writeset);
429: if (errno == EINTR)
430: return;
431: /* Note: we might still have data in the buffers. */
432: sprintf(buf, "select: %.100s\r\n", strerror(errno));
433: buffer_append(&stderr_buffer, buf, strlen(buf));
434: stderr_bytes += strlen(buf);
435: quit_pending = 1;
436: }
437: }
438:
439: void client_suspend_self()
440: {
441: #ifdef SIGWINCH
442: struct winsize oldws, newws;
443: #endif /* SIGWINCH */
444:
445: /* Flush stdout and stderr buffers. */
446: if (buffer_len(&stdout_buffer) > 0)
447: write(fileno(stdout),
448: buffer_ptr(&stdout_buffer),
449: buffer_len(&stdout_buffer));
450: if (buffer_len(&stderr_buffer) > 0)
451: write(fileno(stderr),
452: buffer_ptr(&stderr_buffer),
453: buffer_len(&stderr_buffer));
454:
455: /* Leave raw mode. */
456: leave_raw_mode();
457:
458: /* Free (and clear) the buffer to reduce the
459: amount of data that gets written to swap. */
460: buffer_free(&stdin_buffer);
461: buffer_free(&stdout_buffer);
462: buffer_free(&stderr_buffer);
463:
464: #ifdef SIGWINCH
465: /* Save old window size. */
466: ioctl(fileno(stdin), TIOCGWINSZ, &oldws);
467: #endif /* SIGWINCH */
468:
469: /* Send the suspend signal to the program
470: itself. */
471: kill(getpid(), SIGTSTP);
472:
473: #ifdef SIGWINCH
474: /* Check if the window size has changed. */
475: if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 &&
476: (oldws.ws_row != newws.ws_row || oldws.ws_col != newws.ws_col ||
477: oldws.ws_xpixel != newws.ws_xpixel ||
478: oldws.ws_ypixel != newws.ws_ypixel))
479: received_window_change_signal = 1;
480: #endif /* SIGWINCH */
481:
482: /* OK, we have been continued by the user.
483: Reinitialize buffers. */
484: buffer_init(&stdin_buffer);
485: buffer_init(&stdout_buffer);
486: buffer_init(&stderr_buffer);
487:
488: /* Re-enter raw mode. */
489: enter_raw_mode();
490: }
491:
492: void client_process_input(fd_set *readset)
493: {
494: int len, pid;
495: char buf[8192], *s;
496:
497: /* Read input from the server, and add any such data to the buffer of the
498: packet subsystem. */
499: if (FD_ISSET(connection_in, readset))
500: {
501: /* Read as much as possible. */
502: len = read(connection_in, buf, sizeof(buf));
503: if (len == 0)
504: {
505: /* Received EOF. The remote host has closed the connection. */
506: sprintf(buf, "Connection to %.300s closed by remote host.\r\n",
507: host);
508: buffer_append(&stderr_buffer, buf, strlen(buf));
509: stderr_bytes += strlen(buf);
510: quit_pending = 1;
511: return;
512: }
513:
514: /* There is a kernel bug on Solaris that causes select to sometimes
515: wake up even though there is no data available. */
516: if (len < 0 && errno == EAGAIN)
517: len = 0;
518:
519: if (len < 0)
520: {
521: /* An error has encountered. Perhaps there is a network
522: problem. */
523: sprintf(buf, "Read from remote host %.300s: %.100s\r\n",
524: host, strerror(errno));
525: buffer_append(&stderr_buffer, buf, strlen(buf));
526: stderr_bytes += strlen(buf);
527: quit_pending = 1;
528: return;
529: }
530: packet_process_incoming(buf, len);
531: }
532:
533: /* Read input from stdin. */
534: if (FD_ISSET(fileno(stdin), readset))
535: {
536: /* Read as much as possible. */
537: len = read(fileno(stdin), buf, sizeof(buf));
538: if (len <= 0)
539: {
540: /* Received EOF or error. They are treated similarly,
541: except that an error message is printed if it was
542: an error condition. */
543: if (len < 0)
544: {
545: sprintf(buf, "read: %.100s\r\n", strerror(errno));
546: buffer_append(&stderr_buffer, buf, strlen(buf));
547: stderr_bytes += strlen(buf);
548: }
549: /* Mark that we have seen EOF. */
550: stdin_eof = 1;
551: /* Send an EOF message to the server unless there is data
552: in the buffer. If there is data in the buffer, no message
553: will be sent now. Code elsewhere will send the EOF
554: when the buffer becomes empty if stdin_eof is set. */
555: if (buffer_len(&stdin_buffer) == 0)
556: {
557: packet_start(SSH_CMSG_EOF);
558: packet_send();
559: }
560: }
561: else
562: if (escape_char == -1)
563: {
564: /* Normal successful read, and no escape character. Just
565: append the data to buffer. */
566: buffer_append(&stdin_buffer, buf, len);
567: stdin_bytes += len;
568: }
569: else
570: {
571: /* Normal, successful read. But we have an escape character
572: and have to process the characters one by one. */
573: unsigned int i;
574: for (i = 0; i < len; i++)
575: {
576: unsigned char ch;
577: /* Get one character at a time. */
578: ch = buf[i];
579:
580: /* Check if we have a pending escape character. */
581: if (escape_pending)
582: {
583: /* We have previously seen an escape character. */
584: /* Clear the flag now. */
585: escape_pending = 0;
586: /* Process the escaped character. */
587: switch (ch)
588: {
589: case '.':
590: /* Terminate the connection. */
591: sprintf(buf, "%c.\r\n", escape_char);
592: buffer_append(&stderr_buffer, buf, strlen(buf));
593: stderr_bytes += strlen(buf);
594: quit_pending = 1;
595: return;
596:
597: case 'Z' - 64:
598: /* Suspend the program. */
599: /* Print a message to that effect to the user. */
600: sprintf(buf, "%c^Z\r\n", escape_char);
601: buffer_append(&stderr_buffer, buf, strlen(buf));
602: stderr_bytes += strlen(buf);
603:
604: /* Restore terminal modes and suspend. */
605: client_suspend_self();
606:
607: /* We have been continued. */
608: continue;
609:
610: case '&':
611: /* Detach the program (continue to serve connections,
612: but put in background and no more new
613: connections). */
614: if (!stdin_eof)
615: {
616: /* Sending SSH_CMSG_EOF alone does not always
617: appear to be enough. So we try to send an
618: EOF character first. */
619: packet_start(SSH_CMSG_STDIN_DATA);
620: packet_put_string("\004", 1);
621: packet_send();
622: /* Close stdin. */
623: stdin_eof = 1;
624: if (buffer_len(&stdin_buffer) == 0)
625: {
626: packet_start(SSH_CMSG_EOF);
627: packet_send();
628: }
629: }
630: /* Restore tty modes. */
631: leave_raw_mode();
632:
633: /* Stop listening for new connections. */
634: channel_stop_listening();
635:
636: printf("%c& [backgrounded]\n", escape_char);
637:
638: /* Fork into background. */
639: pid = fork();
640: if (pid < 0)
641: {
642: error("fork: %.100s", strerror(errno));
643: continue;
644: }
645: if (pid != 0)
646: { /* This is the parent. */
647: /* The parent just exits. */
648: exit(0);
649: }
650:
651: /* The child continues serving connections. */
652: continue;
653:
654: case '?':
655: sprintf(buf, "%c?\r\n\
656: Supported escape sequences:\r\n\
657: ~. - terminate connection\r\n\
658: ~^Z - suspend ssh\r\n\
659: ~# - list forwarded connections\r\n\
660: ~& - background ssh (when waiting for connections to terminate)\r\n\
661: ~? - this message\r\n\
662: ~~ - send the escape character by typing it twice\r\n\
663: (Note that escapes are only recognized immediately after newline.)\r\n",
664: escape_char);
665: buffer_append(&stderr_buffer, buf, strlen(buf));
666: continue;
667:
668: case '#':
669: sprintf(buf, "%c#\r\n", escape_char);
670: buffer_append(&stderr_buffer, buf, strlen(buf));
671: s = channel_open_message();
672: buffer_append(&stderr_buffer, s, strlen(s));
673: xfree(s);
674: continue;
675:
676: default:
677: if (ch != escape_char)
678: {
679: /* Escape character followed by non-special
680: character. Append both to the input
681: buffer. */
682: buf[0] = escape_char;
683: buf[1] = ch;
684: buffer_append(&stdin_buffer, buf, 2);
685: stdin_bytes += 2;
686: continue;
687: }
688: /* Note that escape character typed twice falls through
689: here; the latter gets processed as a normal
690: character below. */
691: break;
692: }
693: }
694: else
695: {
696: /* The previous character was not an escape char.
697: Check if this is an escape. */
698: if (last_was_cr && ch == escape_char)
699: {
700: /* It is. Set the flag and continue to next
701: character. */
702: escape_pending = 1;
703: continue;
704: }
705: }
706:
707: /* Normal character. Record whether it was a newline,
708: and append it to the buffer. */
709: last_was_cr = (ch == '\r' || ch == '\n');
710: buf[0] = ch;
711: buffer_append(&stdin_buffer, buf, 1);
712: stdin_bytes += 1;
713: continue;
714: }
715: }
716: }
717: }
718:
719: void client_process_output(fd_set *writeset)
720: {
721: int len;
722: char buf[100];
723:
724: /* Write buffered output to stdout. */
725: if (FD_ISSET(fileno(stdout), writeset))
726: {
727: /* Write as much data as possible. */
728: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
729: buffer_len(&stdout_buffer));
730: if (len <= 0)
731: {
732: if (errno == EAGAIN)
733: len = 0;
734: else
735: {
736: /* An error or EOF was encountered. Put an error message
737: to stderr buffer. */
738: sprintf(buf, "write stdout: %.50s\r\n", strerror(errno));
739: buffer_append(&stderr_buffer, buf, strlen(buf));
740: stderr_bytes += strlen(buf);
741: quit_pending = 1;
742: return;
743: }
744: }
745: /* Consume printed data from the buffer. */
746: buffer_consume(&stdout_buffer, len);
747: }
748:
749: /* Write buffered output to stderr. */
750: if (FD_ISSET(fileno(stderr), writeset))
751: {
752: /* Write as much data as possible. */
753: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
754: buffer_len(&stderr_buffer));
1.2 provos 755: if (len <= 0) {
1.1 deraadt 756: if (errno == EAGAIN)
757: len = 0;
758: else
759: {
760: /* EOF or error, but can't even print error message. */
761: quit_pending = 1;
762: return;
763: }
1.2 provos 764: }
1.1 deraadt 765: /* Consume printed characters from the buffer. */
766: buffer_consume(&stderr_buffer, len);
767: }
768: }
769:
770: /* Implements the interactive session with the server. This is called
771: after the user has been authenticated, and a command has been
772: started on the remote host. If escape_char != -1, it is the character
773: used as an escape character for terminating or suspending the
774: session. */
775:
776: int client_loop(int have_pty, int escape_char_arg)
777: {
778: double start_time, total_time;
779: int len;
780: char buf[100];
781:
782: debug("Entering interactive session.");
783:
784: start_time = get_current_time();
785:
786: /* Initialize variables. */
787: escape_pending = 0;
788: last_was_cr = 1;
789: exit_status = -1;
790: stdin_eof = 0;
791: buffer_high = 64 * 1024;
792: connection_in = packet_get_connection_in();
793: connection_out = packet_get_connection_out();
794: max_fd = connection_in;
795: if (connection_out > max_fd)
796: max_fd = connection_out;
797: stdin_bytes = 0;
798: stdout_bytes = 0;
799: stderr_bytes = 0;
800: quit_pending = 0;
801: escape_char = escape_char_arg;
802:
803: /* Initialize buffers. */
804: buffer_init(&stdin_buffer);
805: buffer_init(&stdout_buffer);
806: buffer_init(&stderr_buffer);
807:
808: /* Set signal handlers to restore non-blocking mode. */
809: signal(SIGINT, signal_handler);
810: signal(SIGQUIT, signal_handler);
811: signal(SIGTERM, signal_handler);
812: signal(SIGPIPE, SIG_IGN);
813: #ifdef SIGWINCH
814: if (have_pty)
815: signal(SIGWINCH, window_change_handler);
816: #endif /* SIGWINCH */
817:
818: /* Enter raw mode if have a pseudo terminal. */
819: if (have_pty)
820: enter_raw_mode();
821:
822: /* Check if we should immediately send of on stdin. */
823: client_check_initial_eof_on_stdin();
824:
825: /* Main loop of the client for the interactive session mode. */
826: while (!quit_pending)
827: {
828: fd_set readset, writeset;
829:
830: /* Precess buffered packets sent by the server. */
831: client_process_buffered_input_packets();
832:
833: /* Make packets of buffered stdin data, and buffer them for sending
834: to the server. */
835: client_make_packets_from_stdin_data();
836:
837: /* Make packets from buffered channel data, and buffer them for sending
838: to the server. */
839: if (packet_not_very_much_data_to_write())
840: channel_output_poll();
841:
842: /* Check if the window size has changed, and buffer a message about
843: it to the server if so. */
844: client_check_window_change();
845:
846: if (quit_pending)
847: break;
848:
849: /* Wait until we have something to do (something becomes available
850: on one of the descriptors). */
851: client_wait_until_can_do_something(&readset, &writeset);
852:
853: if (quit_pending)
854: break;
855:
856: /* Do channel operations. */
857: channel_after_select(&readset, &writeset);
858:
859: /* Process input from the connection and from stdin. Buffer any data
860: that is available. */
861: client_process_input(&readset);
862:
863: /* Process output to stdout and stderr. Output to the connection
864: is processed elsewhere (above). */
865: client_process_output(&writeset);
866:
867: /* Send as much buffered packet data as possible to the sender. */
868: if (FD_ISSET(connection_out, &writeset))
869: packet_write_poll();
870: }
871:
872: /* Terminate the session. */
873:
874: #ifdef SIGWINCH
875: /* Stop watching for window change. */
876: if (have_pty)
877: signal(SIGWINCH, SIG_DFL);
878: #endif /* SIGWINCH */
879:
880: /* Stop listening for connections. */
881: channel_stop_listening();
882:
883: /* In interactive mode (with pseudo tty) display a message indicating that
884: the connection has been closed. */
885: if (have_pty && !quiet_flag)
886: {
887: sprintf(buf, "Connection to %.64s closed.\r\n", host);
888: buffer_append(&stderr_buffer, buf, strlen(buf));
889: stderr_bytes += strlen(buf);
890: }
891:
892: /* Output any buffered data for stdout. */
893: while (buffer_len(&stdout_buffer) > 0)
894: {
895: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
896: buffer_len(&stdout_buffer));
897: if (len <= 0)
898: {
899: error("Write failed flushing stdout buffer.");
900: break;
901: }
902: buffer_consume(&stdout_buffer, len);
903: }
904:
905: /* Output any buffered data for stderr. */
906: while (buffer_len(&stderr_buffer) > 0)
907: {
908: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
909: buffer_len(&stderr_buffer));
910: if (len <= 0)
911: {
912: error("Write failed flushing stderr buffer.");
913: break;
914: }
915: buffer_consume(&stderr_buffer, len);
916: }
917:
918: /* Leave raw mode. */
919: if (have_pty)
920: leave_raw_mode();
921:
922: /* Clear and free any buffers. */
923: memset(buf, 0, sizeof(buf));
924: buffer_free(&stdin_buffer);
925: buffer_free(&stdout_buffer);
926: buffer_free(&stderr_buffer);
927:
928: /* Report bytes transferred, and transfer rates. */
929: total_time = get_current_time() - start_time;
930: debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
931: stdin_bytes, stdout_bytes, stderr_bytes, total_time);
932: if (total_time > 0)
933: debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
934: stdin_bytes / total_time, stdout_bytes / total_time,
935: stderr_bytes / total_time);
936:
937: /* Return the exit status of the program. */
938: debug("Exit status %d", exit_status);
939: return exit_status;
940: }
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