clientloop.c

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