pppd/tty.c

   1 /*
   2  * tty.c - code for handling serial ports in pppd.
   3  *
   4  * Copyright (C) 2000-2004 Paul Mackerras. All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. The name(s) of the authors of this software must not be used to
  14  *    endorse or promote products derived from this software without
  15  *    prior written permission.
  16  *
  17  * 3. Redistributions of any form whatsoever must retain the following
  18  *    acknowledgment:
  19  *    "This product includes software developed by Paul Mackerras
  20  *     <paulus@samba.org>".
  21  *
  22  * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
  23  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  24  * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  25  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  26  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
  27  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  28  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  29  *
  30  * Portions derived from main.c, which is:
  31  *
  32  * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
  33  *
  34  * Redistribution and use in source and binary forms, with or without
  35  * modification, are permitted provided that the following conditions
  36  * are met:
  37  *
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  *
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in
  43  *    the documentation and/or other materials provided with the
  44  *    distribution.
  45  *
  46  * 3. The name "Carnegie Mellon University" must not be used to
  47  *    endorse or promote products derived from this software without
  48  *    prior written permission. For permission or any legal
  49  *    details, please contact
  50  *      Office of Technology Transfer
  51  *      Carnegie Mellon University
  52  *      5000 Forbes Avenue
  53  *      Pittsburgh, PA  15213-3890
  54  *      (412) 268-4387, fax: (412) 268-7395
  55  *      tech-transfer@andrew.cmu.edu
  56  *
  57  * 4. Redistributions of any form whatsoever must retain the following
  58  *    acknowledgment:
  59  *    "This product includes software developed by Computing Services
  60  *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
  61  *
  62  * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
  63  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  64  * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
  65  * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  66  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
  67  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  68  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  69  */
  70
  71 #define RCSID   "$Id: tty.c,v 1.27 2008/07/01 12:27:56 paulus Exp $"
  72
  73 #include <stdio.h>
  74 #include <ctype.h>
  75 #include <stdlib.h>
  76 #include <string.h>
  77 #include <termios.h>
  78 #include <unistd.h>
  79 #include <signal.h>
  80 #include <errno.h>
  81 #include <fcntl.h>
  82 #include <syslog.h>
  83 #include <netdb.h>
  84 #include <utmp.h>
  85 #include <pwd.h>
  86 #include <setjmp.h>
  87 #include <sys/param.h>
  88 #include <sys/types.h>
  89 #include <sys/wait.h>
  90 #include <sys/time.h>
  91 #include <sys/resource.h>
  92 #include <sys/stat.h>
  93 #include <sys/socket.h>
  94 #include <netinet/in.h>
  95 #include <arpa/inet.h>
  96
  97 #include "pppd.h"
  98 #include "fsm.h"
  99 #include "lcp.h"
 100
 101 void tty_process_extra_options __P((void));
 102 void tty_check_options __P((void));
 103 int  connect_tty __P((void));
 104 void disconnect_tty __P((void));
 105 void tty_close_fds __P((void));
 106 void cleanup_tty __P((void));
 107 void tty_do_send_config __P((int, u_int32_t, int, int));
 108
 109 static int setdevname __P((char *, char **, int));
 110 static int setspeed __P((char *, char **, int));
 111 static int setxonxoff __P((char **));
 112 static int setescape __P((char **));
 113 static void printescape __P((option_t *, void (*)(void *, char *,...),void *));
 114 static void finish_tty __P((void));
 115 static int start_charshunt __P((int, int));
 116 static void stop_charshunt __P((void *, int));
 117 static void charshunt_done __P((void *));
 118 static void charshunt __P((int, int, char *));
 119 static int record_write __P((FILE *, int code, u_char *buf, int nb,
 120                              struct timeval *));
 121 static int open_socket __P((char *));
 122 static void maybe_relock __P((void *, int));
 123
 124 static int pty_master;          /* fd for master side of pty */
 125 static int pty_slave;           /* fd for slave side of pty */
 126 static int real_ttyfd;          /* fd for actual serial port (not pty) */
 127 static int ttyfd;               /* Serial port file descriptor */
 128 static char speed_str[16];      /* Serial port speed as string */
 129
 130 mode_t tty_mode = (mode_t)-1;   /* Original access permissions to tty */
 131 int baud_rate;                  /* Actual bits/second for serial device */
 132 char *callback_script;          /* script for doing callback */
 133 int charshunt_pid;              /* Process ID for charshunt */
 134 int locked;                     /* lock() has succeeded */
 135 struct stat devstat;            /* result of stat() on devnam */
 136
 137 /* option variables */
 138 int     crtscts = 0;            /* Use hardware flow control */
 139 bool    modem = 1;              /* Use modem control lines */
 140 int     inspeed = 0;            /* Input/Output speed requested */
 141 bool    lockflag = 0;           /* Create lock file to lock the serial dev */
 142 char    *initializer = NULL;    /* Script to initialize physical link */
 143 char    *connect_script = NULL; /* Script to establish physical link */
 144 char    *disconnect_script = NULL; /* Script to disestablish physical link */
 145 char    *welcomer = NULL;       /* Script to run after phys link estab. */
 146 char    *ptycommand = NULL;     /* Command to run on other side of pty */
 147 bool    notty = 0;              /* Stdin/out is not a tty */
 148 char    *record_file = NULL;    /* File to record chars sent/received */
 149 int     max_data_rate;          /* max bytes/sec through charshunt */
 150 bool    sync_serial = 0;        /* Device is synchronous serial device */
 151 char    *pty_socket = NULL;     /* Socket to connect to pty */
 152 int     using_pty = 0;          /* we're allocating a pty as the device */
 153
 154 extern uid_t uid;
 155 extern int kill_link;
 156 extern int asked_to_quit;
 157 extern int got_sigterm;
 158
 159 /* XXX */
 160 extern int privopen;            /* don't lock, open device as root */
 161
 162 u_int32_t xmit_accm[8];         /* extended transmit ACCM */
 163
 164 /* option descriptors */
 165 option_t tty_options[] = {
 166     /* device name must be first, or change connect_tty() below! */
 167     { "device name", o_wild, (void *) &setdevname,
 168       "Serial port device name",
 169       OPT_DEVNAM | OPT_PRIVFIX | OPT_NOARG  | OPT_A2STRVAL | OPT_STATIC,
 170       devnam},
 171
 172     { "tty speed", o_wild, (void *) &setspeed,
 173       "Baud rate for serial port",
 174       OPT_PRIO | OPT_NOARG | OPT_A2STRVAL | OPT_STATIC, speed_str },
 175
 176     { "lock", o_bool, &lockflag,
 177       "Lock serial device with UUCP-style lock file", OPT_PRIO | 1 },
 178     { "nolock", o_bool, &lockflag,
 179       "Don't lock serial device", OPT_PRIOSUB | OPT_PRIV },
 180
 181     { "init", o_string, &initializer,
 182       "A program to initialize the device", OPT_PRIO | OPT_PRIVFIX },
 183
 184     { "connect", o_string, &connect_script,
 185       "A program to set up a connection", OPT_PRIO | OPT_PRIVFIX },
 186
 187     { "disconnect", o_string, &disconnect_script,
 188       "Program to disconnect serial device", OPT_PRIO | OPT_PRIVFIX },
 189
 190     { "welcome", o_string, &welcomer,
 191       "Script to welcome client", OPT_PRIO | OPT_PRIVFIX },
 192
 193     { "pty", o_string, &ptycommand,
 194       "Script to run on pseudo-tty master side",
 195       OPT_PRIO | OPT_PRIVFIX | OPT_DEVNAM },
 196
 197     { "notty", o_bool, &notty,
 198       "Input/output is not a tty", OPT_DEVNAM | 1 },
 199
 200     { "socket", o_string, &pty_socket,
 201       "Send and receive over socket, arg is host:port",
 202       OPT_PRIO | OPT_DEVNAM },
 203
 204     { "record", o_string, &record_file,
 205       "Record characters sent/received to file", OPT_PRIO },
 206
 207     { "crtscts", o_int, &crtscts,
 208       "Set hardware (RTS/CTS) flow control",
 209       OPT_PRIO | OPT_NOARG | OPT_VAL(1) },
 210     { "cdtrcts", o_int, &crtscts,
 211       "Set alternate hardware (DTR/CTS) flow control",
 212       OPT_PRIOSUB | OPT_NOARG | OPT_VAL(2) },
 213     { "nocrtscts", o_int, &crtscts,
 214       "Disable hardware flow control",
 215       OPT_PRIOSUB | OPT_NOARG | OPT_VAL(-1) },
 216     { "-crtscts", o_int, &crtscts,
 217       "Disable hardware flow control",
 218       OPT_PRIOSUB | OPT_ALIAS | OPT_NOARG | OPT_VAL(-1) },
 219     { "nocdtrcts", o_int, &crtscts,
 220       "Disable hardware flow control",
 221       OPT_PRIOSUB | OPT_ALIAS | OPT_NOARG | OPT_VAL(-1) },
 222     { "xonxoff", o_special_noarg, (void *)setxonxoff,
 223       "Set software (XON/XOFF) flow control", OPT_PRIOSUB },
 224
 225     { "modem", o_bool, &modem,
 226       "Use modem control lines", OPT_PRIO | 1 },
 227     { "local", o_bool, &modem,
 228       "Don't use modem control lines", OPT_PRIOSUB | 0 },
 229
 230     { "sync", o_bool, &sync_serial,
 231       "Use synchronous HDLC serial encoding", 1 },
 232
 233     { "datarate", o_int, &max_data_rate,
 234       "Maximum data rate in bytes/sec (with pty, notty or record option)",
 235       OPT_PRIO },
 236
 237     { "escape", o_special, (void *)setescape,
 238       "List of character codes to escape on transmission",
 239       OPT_A2PRINTER, (void *)printescape },
 240
 241     { NULL }
 242 };
 243
 244
 245 struct channel tty_channel = {
 246         tty_options,
 247         &tty_process_extra_options,
 248         &tty_check_options,
 249         &connect_tty,
 250         &disconnect_tty,
 251         &tty_establish_ppp,
 252         &tty_disestablish_ppp,
 253         &tty_do_send_config,
 254         &tty_recv_config,
 255         &cleanup_tty,
 256         &tty_close_fds
 257 };
 258
 259 /*
 260  * setspeed - Set the serial port baud rate.
 261  * If doit is 0, the call is to check whether this option is
 262  * potentially a speed value.
 263  */
 264 static int
 265 setspeed(arg, argv, doit)
 266     char *arg;
 267     char **argv;
 268     int doit;
 269 {
 270         char *ptr;
 271         int spd;
 272
 273         spd = strtol(arg, &ptr, 0);
 274         if (ptr == arg || *ptr != 0 || spd == 0)
 275                 return 0;
 276         if (doit) {
 277                 inspeed = spd;
 278                 slprintf(speed_str, sizeof(speed_str), "%d", spd);
 279         }
 280         return 1;
 281 }
 282
 283
 284 /*
 285  * setdevname - Set the device name.
 286  * If doit is 0, the call is to check whether this option is
 287  * potentially a device name.
 288  */
 289 static int
 290 setdevname(cp, argv, doit)
 291     char *cp;
 292     char **argv;
 293     int doit;
 294 {
 295         struct stat statbuf;
 296         char dev[MAXPATHLEN];
 297
 298         if (*cp == 0)
 299                 return 0;
 300
 301         if (*cp != '/') {
 302                 strlcpy(dev, "/dev/", sizeof(dev));
 303                 strlcat(dev, cp, sizeof(dev));
 304                 cp = dev;
 305         }
 306
 307         /*
 308          * Check if there is a character device by this name.
 309          */
 310         if (stat(cp, &statbuf) < 0) {
 311                 if (!doit)
 312                         return errno != ENOENT;
 313                 option_error("Couldn't stat %s: %m", cp);
 314                 return 0;
 315         }
 316         if (!S_ISCHR(statbuf.st_mode)) {
 317                 if (doit)
 318                         option_error("%s is not a character device", cp);
 319                 return 0;
 320         }
 321
 322         if (doit) {
 323                 strlcpy(devnam, cp, sizeof(devnam));
 324                 devstat = statbuf;
 325                 default_device = 0;
 326         }
 327
 328         return 1;
 329 }
 330
 331 static int
 332 setxonxoff(argv)
 333     char **argv;
 334 {
 335         lcp_wantoptions[0].asyncmap |= 0x000A0000;      /* escape ^S and ^Q */
 336         lcp_wantoptions[0].neg_asyncmap = 1;
 337
 338         crtscts = -2;
 339         return 1;
 340 }
 341
 342 /*
 343  * setescape - add chars to the set we escape on transmission.
 344  */
 345 static int
 346 setescape(argv)
 347     char **argv;
 348 {
 349     int n, ret;
 350     char *p, *endp;
 351
 352     p = *argv;
 353     ret = 1;
 354     while (*p) {
 355         n = strtol(p, &endp, 16);
 356         if (p == endp) {
 357             option_error("escape parameter contains invalid hex number '%s'",
 358                          p);
 359             return 0;
 360         }
 361         p = endp;
 362         if (n < 0 || n == 0x5E || n > 0xFF) {
 363             option_error("can't escape character 0x%x", n);
 364             ret = 0;
 365         } else
 366             xmit_accm[n >> 5] |= 1 << (n & 0x1F);
 367         while (*p == ',' || *p == ' ')
 368             ++p;
 369     }
 370     lcp_allowoptions[0].asyncmap = xmit_accm[0];
 371     return ret;
 372 }
 373
 374 static void
 375 printescape(opt, printer, arg)
 376     option_t *opt;
 377     void (*printer) __P((void *, char *, ...));
 378     void *arg;
 379 {
 380         int n;
 381         int first = 1;
 382
 383         for (n = 0; n < 256; ++n) {
 384                 if (n == 0x7d)
 385                         n += 2;         /* skip 7d, 7e */
 386                 if (xmit_accm[n >> 5] & (1 << (n & 0x1f))) {
 387                         if (!first)
 388                                 printer(arg, ",");
 389                         else
 390                                 first = 0;
 391                         printer(arg, "%x", n);
 392                 }
 393         }
 394         if (first)
 395                 printer(arg, "oops # nothing escaped");
 396 }
 397
 398 /*
 399  * tty_init - do various tty-related initializations.
 400  */
 401 void tty_init()
 402 {
 403     add_notifier(&pidchange, maybe_relock, 0);
 404     the_channel = &tty_channel;
 405     xmit_accm[3] = 0x60000000;
 406 }
 407
 408 /*
 409  * tty_process_extra_options - work out which tty device we are using
 410  * and read its options file.
 411  */
 412 void tty_process_extra_options()
 413 {
 414         using_pty = notty || ptycommand != NULL || pty_socket != NULL;
 415         if (using_pty)
 416                 return;
 417         if (default_device) {
 418                 char *p;
 419                 if (!isatty(0) || (p = ttyname(0)) == NULL) {
 420                         option_error("no device specified and stdin is not a tty");
 421                         exit(EXIT_OPTION_ERROR);
 422                 }
 423                 strlcpy(devnam, p, sizeof(devnam));
 424                 if (stat(devnam, &devstat) < 0)
 425                         fatal("Couldn't stat default device %s: %m", devnam);
 426         }
 427
 428
 429         /*
 430          * Parse the tty options file.
 431          * The per-tty options file should not change
 432          * ptycommand, pty_socket, notty or devnam.
 433          * options_for_tty doesn't override options set on the command line,
 434          * except for some privileged options.
 435          */
 436         if (!options_for_tty())
 437                 exit(EXIT_OPTION_ERROR);
 438 }
 439
 440 /*
 441  * tty_check_options - do consistency checks on the options we were given.
 442  */
 443 void
 444 tty_check_options()
 445 {
 446         struct stat statbuf;
 447         int fdflags;
 448
 449         if (demand && notty) {
 450                 option_error("demand-dialling is incompatible with notty");
 451                 exit(EXIT_OPTION_ERROR);
 452         }
 453         if (demand && connect_script == 0 && ptycommand == NULL
 454             && pty_socket == NULL) {
 455                 option_error("connect script is required for demand-dialling\n");
 456                 exit(EXIT_OPTION_ERROR);
 457         }
 458         /* default holdoff to 0 if no connect script has been given */
 459         if (connect_script == 0 && !holdoff_specified)
 460                 holdoff = 0;
 461
 462         if (using_pty) {
 463                 if (!default_device) {
 464                         option_error("%s option precludes specifying device name",
 465                                      pty_socket? "socket": notty? "notty": "pty");
 466                         exit(EXIT_OPTION_ERROR);
 467                 }
 468                 if (ptycommand != NULL && notty) {
 469                         option_error("pty option is incompatible with notty option");
 470                         exit(EXIT_OPTION_ERROR);
 471                 }
 472                 if (pty_socket != NULL && (ptycommand != NULL || notty)) {
 473                         option_error("socket option is incompatible with pty and notty");
 474                         exit(EXIT_OPTION_ERROR);
 475                 }
 476                 default_device = notty;
 477                 lockflag = 0;
 478                 modem = 0;
 479                 if (notty && log_to_fd <= 1)
 480                         log_to_fd = -1;
 481         } else {
 482                 /*
 483                  * If the user has specified a device which is the same as
 484                  * the one on stdin, pretend they didn't specify any.
 485                  * If the device is already open read/write on stdin,
 486                  * we assume we don't need to lock it, and we can open it
 487                  * as root.
 488                  */
 489                 if (fstat(0, &statbuf) >= 0 && S_ISCHR(statbuf.st_mode)
 490                     && statbuf.st_rdev == devstat.st_rdev) {
 491                         default_device = 1;
 492                         fdflags = fcntl(0, F_GETFL);
 493                         if (fdflags != -1 && (fdflags & O_ACCMODE) == O_RDWR)
 494                                 privopen = 1;
 495                 }
 496         }
 497         if (default_device)
 498                 nodetach = 1;
 499
 500         /*
 501          * Don't send log messages to the serial port, it tends to
 502          * confuse the peer. :-)
 503          */
 504         if (log_to_fd >= 0 && fstat(log_to_fd, &statbuf) >= 0
 505             && S_ISCHR(statbuf.st_mode) && statbuf.st_rdev == devstat.st_rdev)
 506                 log_to_fd = -1;
 507 }
 508
 509 /*
 510  * connect_tty - get the serial port ready to start doing PPP.
 511  * That is, open the serial port, set its speed and mode, and run
 512  * the connector and/or welcomer.
 513  */
 514 int connect_tty()
 515 {
 516         char *connector;
 517         int fdflags;
 518 #ifndef __linux__
 519         struct stat statbuf;
 520 #endif
 521         char numbuf[16];
 522
 523         /*
 524          * Get a pty master/slave pair if the pty, notty, socket,
 525          * or record options were specified.
 526          */
 527         strlcpy(ppp_devnam, devnam, sizeof(ppp_devnam));
 528         pty_master = -1;
 529         pty_slave = -1;
 530         real_ttyfd = -1;
 531         if (using_pty || record_file != NULL) {
 532                 if (!get_pty(&pty_master, &pty_slave, ppp_devnam, uid)) {
 533                         error("Couldn't allocate pseudo-tty");
 534                         status = EXIT_FATAL_ERROR;
 535                         return -1;
 536                 }
 537                 set_up_tty(pty_slave, 1);
 538         }
 539
 540         /*
 541          * Lock the device if we've been asked to.
 542          */
 543         status = EXIT_LOCK_FAILED;
 544         if (lockflag && !privopen) {
 545                 if (lock(devnam) < 0)
 546                         goto errret;
 547                 locked = 1;
 548         }
 549
 550         /*
 551          * Open the serial device and set it up to be the ppp interface.
 552          * First we open it in non-blocking mode so we can set the
 553          * various termios flags appropriately.  If we aren't dialling
 554          * out and we want to use the modem lines, we reopen it later
 555          * in order to wait for the carrier detect signal from the modem.
 556          */
 557         got_sigterm = 0;
 558         connector = doing_callback? callback_script: connect_script;
 559         if (devnam[0] != 0) {
 560                 for (;;) {
 561                         /* If the user specified the device name, become the
 562                            user before opening it. */
 563                         int err, prio;
 564
 565                         prio = privopen? OPRIO_ROOT: tty_options[0].priority;
 566                         if (prio < OPRIO_ROOT && seteuid(uid) == -1) {
 567                                 error("Unable to drop privileges before opening %s: %m\n",
 568                                       devnam);
 569                                 status = EXIT_OPEN_FAILED;
 570                                 goto errret;
 571                         }
 572                         real_ttyfd = open(devnam, O_NONBLOCK | O_RDWR, 0);
 573                         err = errno;
 574                         if (prio < OPRIO_ROOT && seteuid(0) == -1)
 575                                 fatal("Unable to regain privileges");
 576                         if (real_ttyfd >= 0)
 577                                 break;
 578                         errno = err;
 579                         if (err != EINTR) {
 580                                 error("Failed to open %s: %m", devnam);
 581                                 status = EXIT_OPEN_FAILED;
 582                         }
 583                         if (!persist || err != EINTR)
 584                                 goto errret;
 585                 }
 586                 ttyfd = real_ttyfd;
 587                 if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
 588                     || fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
 589                         warn("Couldn't reset non-blocking mode on device: %m");
 590
 591 #ifndef __linux__
 592                 /*
 593                  * Linux 2.4 and above blocks normal writes to the tty
 594                  * when it is in PPP line discipline, so this isn't needed.
 595                  */
 596                 /*
 597                  * Do the equivalent of `mesg n' to stop broadcast messages.
 598                  */
 599                 if (fstat(ttyfd, &statbuf) < 0
 600                     || fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) {
 601                         warn("Couldn't restrict write permissions to %s: %m", devnam);
 602                 } else
 603                         tty_mode = statbuf.st_mode;
 604 #endif /* __linux__ */
 605
 606                 /*
 607                  * Set line speed, flow control, etc.
 608                  * If we have a non-null connection or initializer script,
 609                  * on most systems we set CLOCAL for now so that we can talk
 610                  * to the modem before carrier comes up.  But this has the
 611                  * side effect that we might miss it if CD drops before we
 612                  * get to clear CLOCAL below.  On systems where we can talk
 613                  * successfully to the modem with CLOCAL clear and CD down,
 614                  * we could clear CLOCAL at this point.
 615                  */
 616                 set_up_tty(ttyfd, ((connector != NULL && connector[0] != 0)
 617                                    || initializer != NULL));
 618         }
 619
 620         /*
 621          * If the pty, socket, notty and/or record option was specified,
 622          * start up the character shunt now.
 623          */
 624         status = EXIT_PTYCMD_FAILED;
 625         if (ptycommand != NULL) {
 626                 if (record_file != NULL) {
 627                         int ipipe[2], opipe[2], ok;
 628
 629                         if (pipe(ipipe) < 0 || pipe(opipe) < 0)
 630                                 fatal("Couldn't create pipes for record option: %m");
 631
 632                         /* don't leak these to the ptycommand */
 633                         (void) fcntl(ipipe[0], F_SETFD, FD_CLOEXEC);
 634                         (void) fcntl(opipe[1], F_SETFD, FD_CLOEXEC);
 635
 636                         ok = device_script(ptycommand, opipe[0], ipipe[1], 1) == 0
 637                                 && start_charshunt(ipipe[0], opipe[1]);
 638                         close(ipipe[0]);
 639                         close(ipipe[1]);
 640                         close(opipe[0]);
 641                         close(opipe[1]);
 642                         if (!ok)
 643                                 goto errret;
 644                 } else {
 645                         if (device_script(ptycommand, pty_master, pty_master, 1) < 0)
 646                                 goto errret;
 647                 }
 648         } else if (pty_socket != NULL) {
 649                 int fd = open_socket(pty_socket);
 650                 if (fd < 0)
 651                         goto errret;
 652                 if (!start_charshunt(fd, fd))
 653                         goto errret;
 654                 close(fd);
 655         } else if (notty) {
 656                 if (!start_charshunt(0, 1))
 657                         goto errret;
 658                 dup2(fd_devnull, 0);
 659                 dup2(fd_devnull, 1);
 660                 if (log_to_fd == 1)
 661                         log_to_fd = -1;
 662                 if (log_to_fd != 2)
 663                         dup2(fd_devnull, 2);
 664         } else if (record_file != NULL) {
 665                 int fd = dup(ttyfd);
 666                 if (!start_charshunt(fd, fd))
 667                         goto errret;
 668         }
 669
 670         if (using_pty || record_file != NULL) {
 671                 ttyfd = pty_slave;
 672                 close(pty_master);
 673                 pty_master = -1;
 674         }
 675
 676         /* run connection script */
 677         if ((connector && connector[0]) || initializer) {
 678                 if (real_ttyfd != -1) {
 679                         /* XXX do this if doing_callback == CALLBACK_DIALIN? */
 680                         if (!default_device && modem) {
 681                                 setdtr(real_ttyfd, 0);  /* in case modem is off hook */
 682                                 sleep(1);
 683                                 setdtr(real_ttyfd, 1);
 684                         }
 685                 }
 686
 687                 if (initializer && initializer[0]) {
 688                         if (device_script(initializer, ttyfd, ttyfd, 0) < 0) {
 689                                 error("Initializer script failed");
 690                                 status = EXIT_INIT_FAILED;
 691                                 goto errretf;
 692                         }
 693                         if (got_sigterm) {
 694                                 disconnect_tty();
 695                                 goto errretf;
 696                         }
 697                         info("Serial port initialized.");
 698                 }
 699
 700                 if (connector && connector[0]) {
 701                         if (device_script(connector, ttyfd, ttyfd, 0) < 0) {
 702                                 error("Connect script failed");
 703                                 status = EXIT_CONNECT_FAILED;
 704                                 goto errretf;
 705                         }
 706                         if (got_sigterm) {
 707                                 disconnect_tty();
 708                                 goto errretf;
 709                         }
 710                         info("Serial connection established.");
 711                 }
 712
 713                 /* set line speed, flow control, etc.;
 714                    clear CLOCAL if modem option */
 715                 if (real_ttyfd != -1)
 716                         set_up_tty(real_ttyfd, 0);
 717
 718                 if (doing_callback == CALLBACK_DIALIN)
 719                         connector = NULL;
 720         }
 721
 722         /* reopen tty if necessary to wait for carrier */
 723         if (connector == NULL && modem && devnam[0] != 0) {
 724                 int i;
 725                 for (;;) {
 726                         if ((i = open(devnam, O_RDWR)) >= 0)
 727                                 break;
 728                         if (errno != EINTR) {
 729                                 error("Failed to reopen %s: %m", devnam);
 730                                 status = EXIT_OPEN_FAILED;
 731                         }
 732                         if (!persist || errno != EINTR || hungup || got_sigterm)
 733                                 goto errret;
 734                 }
 735                 close(i);
 736         }
 737
 738         slprintf(numbuf, sizeof(numbuf), "%d", baud_rate);
 739         script_setenv("SPEED", numbuf, 0);
 740
 741         /* run welcome script, if any */
 742         if (welcomer && welcomer[0]) {
 743                 if (device_script(welcomer, ttyfd, ttyfd, 0) < 0)
 744                         warn("Welcome script failed");
 745         }
 746
 747         /*
 748          * If we are initiating this connection, wait for a short
 749          * time for something from the peer.  This can avoid bouncing
 750          * our packets off his tty before he has it set up.
 751          */
 752         if (connector != NULL || ptycommand != NULL || pty_socket != NULL)
 753                 listen_time = connect_delay;
 754
 755         return ttyfd;
 756
 757  errretf:
 758         if (real_ttyfd >= 0)
 759                 tcflush(real_ttyfd, TCIOFLUSH);
 760  errret:
 761         if (pty_master >= 0) {
 762                 close(pty_master);
 763                 pty_master = -1;
 764         }
 765         ttyfd = -1;
 766         if (got_sigterm)
 767                 asked_to_quit = 1;
 768         return -1;
 769 }
 770
 771
 772 void disconnect_tty()
 773 {
 774         if (disconnect_script == NULL || hungup)
 775                 return;
 776         if (real_ttyfd >= 0)
 777                 set_up_tty(real_ttyfd, 1);
 778         if (device_script(disconnect_script, ttyfd, ttyfd, 0) < 0) {
 779                 warn("disconnect script failed");
 780         } else {
 781                 info("Serial link disconnected.");
 782         }
 783         stop_charshunt(NULL, 0);
 784 }
 785
 786 void tty_close_fds()
 787 {
 788         if (pty_slave >= 0)
 789                 close(pty_slave);
 790         if (real_ttyfd >= 0) {
 791                 close(real_ttyfd);
 792                 real_ttyfd = -1;
 793         }
 794         /* N.B. ttyfd will == either pty_slave or real_ttyfd */
 795 }
 796
 797 void cleanup_tty()
 798 {
 799         if (real_ttyfd >= 0)
 800                 finish_tty();
 801         tty_close_fds();
 802         if (locked) {
 803                 unlock();
 804                 locked = 0;
 805         }
 806 }
 807
 808 /*
 809  * tty_do_send_config - set transmit-side PPP configuration.
 810  * We set the extended transmit ACCM here as well.
 811  */
 812 void
 813 tty_do_send_config(mtu, accm, pcomp, accomp)
 814     int mtu;
 815     u_int32_t accm;
 816     int pcomp, accomp;
 817 {
 818         tty_set_xaccm(xmit_accm);
 819         tty_send_config(mtu, accm, pcomp, accomp);
 820 }
 821
 822 /*
 823  * finish_tty - restore the terminal device to its original settings
 824  */
 825 static void
 826 finish_tty()
 827 {
 828         /* drop dtr to hang up */
 829         if (!default_device && modem) {
 830                 setdtr(real_ttyfd, 0);
 831                 /*
 832                  * This sleep is in case the serial port has CLOCAL set by default,
 833                  * and consequently will reassert DTR when we close the device.
 834                  */
 835                 sleep(1);
 836         }
 837
 838         restore_tty(real_ttyfd);
 839
 840 #ifndef __linux__
 841         if (tty_mode != (mode_t) -1) {
 842                 if (fchmod(real_ttyfd, tty_mode) != 0)
 843                         error("Couldn't restore tty permissions");
 844         }
 845 #endif /* __linux__ */
 846
 847         close(real_ttyfd);
 848         real_ttyfd = -1;
 849 }
 850
 851 /*
 852  * maybe_relock - our PID has changed, maybe update the lock file.
 853  */
 854 static void
 855 maybe_relock(arg, pid)
 856     void *arg;
 857     int pid;
 858 {
 859     if (locked)
 860         relock(pid);
 861 }
 862
 863 /*
 864  * open_socket - establish a stream socket connection to the nominated
 865  * host and port.
 866  */
 867 static int
 868 open_socket(dest)
 869     char *dest;
 870 {
 871     char *sep, *endp = NULL;
 872     int sock, port = -1;
 873     u_int32_t host;
 874     struct hostent *hent;
 875     struct sockaddr_in sad;
 876
 877     /* parse host:port and resolve host to an IP address */
 878     sep = strchr(dest, ':');
 879     if (sep != NULL)
 880         port = strtol(sep+1, &endp, 10);
 881     if (port < 0 || endp == sep+1 || sep == dest) {
 882         error("Can't parse host:port for socket destination");
 883         return -1;
 884     }
 885     *sep = 0;
 886     host = inet_addr(dest);
 887     if (host == (u_int32_t) -1) {
 888         hent = gethostbyname(dest);
 889         if (hent == NULL) {
 890             error("%s: unknown host in socket option", dest);
 891             *sep = ':';
 892             return -1;
 893         }
 894         host = *(u_int32_t *)(hent->h_addr_list[0]);
 895     }
 896     *sep = ':';
 897
 898     /* get a socket and connect it to the other end */
 899     sock = socket(PF_INET, SOCK_STREAM, 0);
 900     if (sock < 0) {
 901         error("Can't create socket: %m");
 902         return -1;
 903     }
 904     memset(&sad, 0, sizeof(sad));
 905     sad.sin_family = AF_INET;
 906     sad.sin_port = htons(port);
 907     sad.sin_addr.s_addr = host;
 908     if (connect(sock, (struct sockaddr *)&sad, sizeof(sad)) < 0) {
 909         error("Can't connect to %s: %m", dest);
 910         close(sock);
 911         return -1;
 912     }
 913
 914     return sock;
 915 }
 916
 917
 918 /*
 919  * start_charshunt - create a child process to run the character shunt.
 920  */
 921 static int
 922 start_charshunt(ifd, ofd)
 923     int ifd, ofd;
 924 {
 925     int cpid;
 926
 927     cpid = safe_fork(ifd, ofd, (log_to_fd >= 0? log_to_fd: 2));
 928     if (cpid == -1) {
 929         error("Can't fork process for character shunt: %m");
 930         return 0;
 931     }
 932     if (cpid == 0) {
 933         /* child */
 934         reopen_log();
 935         if (!nodetach)
 936             log_to_fd = -1;
 937         else if (log_to_fd >= 0)
 938             log_to_fd = 2;
 939         setgid(getgid());
 940         setuid(uid);
 941         if (getuid() != uid)
 942             fatal("setuid failed");
 943         charshunt(0, 1, record_file);
 944         exit(0);
 945     }
 946     charshunt_pid = cpid;
 947     record_child(cpid, "pppd (charshunt)", charshunt_done, NULL, 1);
 948     return 1;
 949 }
 950
 951 static void
 952 charshunt_done(arg)
 953     void *arg;
 954 {
 955         charshunt_pid = 0;
 956 }
 957
 958 static void
 959 stop_charshunt(arg, sig)
 960     void *arg;
 961     int sig;
 962 {
 963         if (charshunt_pid)
 964                 kill(charshunt_pid, (sig == SIGINT? sig: SIGTERM));
 965 }
 966
 967 /*
 968  * charshunt - the character shunt, which passes characters between
 969  * the pty master side and the serial port (or stdin/stdout).
 970  * This runs as the user (not as root).
 971  * (We assume ofd >= ifd which is true the way this gets called. :-).
 972  */
 973 static void
 974 charshunt(ifd, ofd, record_file)
 975     int ifd, ofd;
 976     char *record_file;
 977 {
 978     int n, nfds;
 979     fd_set ready, writey;
 980     u_char *ibufp, *obufp;
 981     int nibuf, nobuf;
 982     int flags;
 983     int pty_readable, stdin_readable;
 984     struct timeval lasttime;
 985     FILE *recordf = NULL;
 986     int ilevel, olevel, max_level;
 987     struct timeval levelt, tout, *top;
 988     extern u_char inpacket_buf[];
 989
 990     /*
 991      * Reset signal handlers.
 992      */
 993     signal(SIGHUP, SIG_IGN);            /* Hangup */
 994     signal(SIGINT, SIG_DFL);            /* Interrupt */
 995     signal(SIGTERM, SIG_DFL);           /* Terminate */
 996     signal(SIGCHLD, SIG_DFL);
 997     signal(SIGUSR1, SIG_DFL);
 998     signal(SIGUSR2, SIG_DFL);
 999     signal(SIGABRT, SIG_DFL);
1000     signal(SIGALRM, SIG_DFL);
1001     signal(SIGFPE, SIG_DFL);
1002     signal(SIGILL, SIG_DFL);
1003     signal(SIGPIPE, SIG_DFL);
1004     signal(SIGQUIT, SIG_DFL);
1005     signal(SIGSEGV, SIG_DFL);
1006 #ifdef SIGBUS
1007     signal(SIGBUS, SIG_DFL);
1008 #endif
1009 #ifdef SIGEMT
1010     signal(SIGEMT, SIG_DFL);
1011 #endif
1012 #ifdef SIGPOLL
1013     signal(SIGPOLL, SIG_DFL);
1014 #endif
1015 #ifdef SIGPROF
1016     signal(SIGPROF, SIG_DFL);
1017 #endif
1018 #ifdef SIGSYS
1019     signal(SIGSYS, SIG_DFL);
1020 #endif
1021 #ifdef SIGTRAP
1022     signal(SIGTRAP, SIG_DFL);
1023 #endif
1024 #ifdef SIGVTALRM
1025     signal(SIGVTALRM, SIG_DFL);
1026 #endif
1027 #ifdef SIGXCPU
1028     signal(SIGXCPU, SIG_DFL);
1029 #endif
1030 #ifdef SIGXFSZ
1031     signal(SIGXFSZ, SIG_DFL);
1032 #endif
1033
1034     /*
1035      * Check that the fds won't overrun the fd_sets
1036      */
1037     if (ifd >= FD_SETSIZE || ofd >= FD_SETSIZE || pty_master >= FD_SETSIZE)
1038         fatal("internal error: file descriptor too large (%d, %d, %d)",
1039               ifd, ofd, pty_master);
1040
1041     /*
1042      * Open the record file if required.
1043      */
1044     if (record_file != NULL) {
1045         recordf = fopen(record_file, "a");
1046         if (recordf == NULL)
1047             error("Couldn't create record file %s: %m", record_file);
1048     }
1049
1050     /* set all the fds to non-blocking mode */
1051     flags = fcntl(pty_master, F_GETFL);
1052     if (flags == -1
1053         || fcntl(pty_master, F_SETFL, flags | O_NONBLOCK) == -1)
1054         warn("couldn't set pty master to nonblock: %m");
1055     flags = fcntl(ifd, F_GETFL);
1056     if (flags == -1
1057         || fcntl(ifd, F_SETFL, flags | O_NONBLOCK) == -1)
1058         warn("couldn't set %s to nonblock: %m", (ifd==0? "stdin": "tty"));
1059     if (ofd != ifd) {
1060         flags = fcntl(ofd, F_GETFL);
1061         if (flags == -1
1062             || fcntl(ofd, F_SETFL, flags | O_NONBLOCK) == -1)
1063             warn("couldn't set stdout to nonblock: %m");
1064     }
1065
1066     nibuf = nobuf = 0;
1067     ibufp = obufp = NULL;
1068     pty_readable = stdin_readable = 1;
1069
1070     ilevel = olevel = 0;
1071     gettimeofday(&levelt, NULL);
1072     if (max_data_rate) {
1073         max_level = max_data_rate / 10;
1074         if (max_level < 100)
1075             max_level = 100;
1076     } else
1077         max_level = PPP_MRU + PPP_HDRLEN + 1;
1078
1079     nfds = (ofd > pty_master? ofd: pty_master) + 1;
1080     if (recordf != NULL) {
1081         gettimeofday(&lasttime, NULL);
1082         putc(7, recordf);       /* put start marker */
1083         putc(lasttime.tv_sec >> 24, recordf);
1084         putc(lasttime.tv_sec >> 16, recordf);
1085         putc(lasttime.tv_sec >> 8, recordf);
1086         putc(lasttime.tv_sec, recordf);
1087         lasttime.tv_usec = 0;
1088     }
1089
1090     while (nibuf != 0 || nobuf != 0 || pty_readable || stdin_readable) {
1091         top = 0;
1092         tout.tv_sec = 0;
1093         tout.tv_usec = 10000;
1094         FD_ZERO(&ready);
1095         FD_ZERO(&writey);
1096         if (nibuf != 0) {
1097             if (ilevel >= max_level)
1098                 top = &tout;
1099             else
1100                 FD_SET(pty_master, &writey);
1101         } else if (stdin_readable)
1102             FD_SET(ifd, &ready);
1103         if (nobuf != 0) {
1104             if (olevel >= max_level)
1105                 top = &tout;
1106             else
1107                 FD_SET(ofd, &writey);
1108         } else if (pty_readable)
1109             FD_SET(pty_master, &ready);
1110         if (select(nfds, &ready, &writey, NULL, top) < 0) {
1111             if (errno != EINTR)
1112                 fatal("select");
1113             continue;
1114         }
1115         if (max_data_rate) {
1116             double dt;
1117             int nbt;
1118             struct timeval now;
1119
1120             gettimeofday(&now, NULL);
1121             dt = (now.tv_sec - levelt.tv_sec
1122                   + (now.tv_usec - levelt.tv_usec) / 1e6);
1123             nbt = (int)(dt * max_data_rate);
1124             ilevel = (nbt < 0 || nbt > ilevel)? 0: ilevel - nbt;
1125             olevel = (nbt < 0 || nbt > olevel)? 0: olevel - nbt;
1126             levelt = now;
1127         } else
1128             ilevel = olevel = 0;
1129         if (FD_ISSET(ifd, &ready)) {
1130             ibufp = inpacket_buf;
1131             nibuf = read(ifd, ibufp, PPP_MRU + PPP_HDRLEN);
1132             if (nibuf < 0 && errno == EIO)
1133                 nibuf = 0;
1134             if (nibuf < 0) {
1135                 if (!(errno == EINTR || errno == EAGAIN)) {
1136                     error("Error reading standard input: %m");
1137                     break;
1138                 }
1139                 nibuf = 0;
1140             } else if (nibuf == 0) {
1141                 /* end of file from stdin */
1142                 stdin_readable = 0;
1143                 if (recordf)
1144                     if (!record_write(recordf, 4, NULL, 0, &lasttime))
1145                         recordf = NULL;
1146             } else {
1147                 FD_SET(pty_master, &writey);
1148                 if (recordf)
1149                     if (!record_write(recordf, 2, ibufp, nibuf, &lasttime))
1150                         recordf = NULL;
1151             }
1152         }
1153         if (FD_ISSET(pty_master, &ready)) {
1154             obufp = outpacket_buf;
1155             nobuf = read(pty_master, obufp, PPP_MRU + PPP_HDRLEN);
1156             if (nobuf < 0 && errno == EIO)
1157                 nobuf = 0;
1158             if (nobuf < 0) {
1159                 if (!(errno == EINTR || errno == EAGAIN)) {
1160                     error("Error reading pseudo-tty master: %m");
1161                     break;
1162                 }
1163                 nobuf = 0;
1164             } else if (nobuf == 0) {
1165                 /* end of file from the pty - slave side has closed */
1166                 pty_readable = 0;
1167                 stdin_readable = 0;     /* pty is not writable now */
1168                 nibuf = 0;
1169                 close(ofd);
1170                 if (recordf)
1171                     if (!record_write(recordf, 3, NULL, 0, &lasttime))
1172                         recordf = NULL;
1173             } else {
1174                 FD_SET(ofd, &writey);
1175                 if (recordf)
1176                     if (!record_write(recordf, 1, obufp, nobuf, &lasttime))
1177                         recordf = NULL;
1178             }
1179         } else if (!stdin_readable)
1180             pty_readable = 0;
1181         if (FD_ISSET(ofd, &writey)) {
1182             n = nobuf;
1183             if (olevel + n > max_level)
1184                 n = max_level - olevel;
1185             n = write(ofd, obufp, n);
1186             if (n < 0) {
1187                 if (errno == EIO) {
1188                     pty_readable = 0;
1189                     nobuf = 0;
1190                 } else if (errno != EAGAIN && errno != EINTR) {
1191                     error("Error writing standard output: %m");
1192                     break;
1193                 }
1194             } else {
1195                 obufp += n;
1196                 nobuf -= n;
1197                 olevel += n;
1198             }
1199         }
1200         if (FD_ISSET(pty_master, &writey)) {
1201             n = nibuf;
1202             if (ilevel + n > max_level)
1203                 n = max_level - ilevel;
1204             n = write(pty_master, ibufp, n);
1205             if (n < 0) {
1206                 if (errno == EIO) {
1207                     stdin_readable = 0;
1208                     nibuf = 0;
1209                 } else if (errno != EAGAIN && errno != EINTR) {
1210                     error("Error writing pseudo-tty master: %m");
1211                     break;
1212                 }
1213             } else {
1214                 ibufp += n;
1215                 nibuf -= n;
1216                 ilevel += n;
1217             }
1218         }
1219     }
1220     exit(0);
1221 }
1222
1223 static int
1224 record_write(f, code, buf, nb, tp)
1225     FILE *f;
1226     int code;
1227     u_char *buf;
1228     int nb;
1229     struct timeval *tp;
1230 {
1231     struct timeval now;
1232     int diff;
1233
1234     gettimeofday(&now, NULL);
1235     now.tv_usec /= 100000;      /* actually 1/10 s, not usec now */
1236     diff = (now.tv_sec - tp->tv_sec) * 10 + (now.tv_usec - tp->tv_usec);
1237     if (diff > 0) {
1238         if (diff > 255) {
1239             putc(5, f);
1240             putc(diff >> 24, f);
1241             putc(diff >> 16, f);
1242             putc(diff >> 8, f);
1243             putc(diff, f);
1244         } else {
1245             putc(6, f);
1246             putc(diff, f);
1247         }
1248         *tp = now;
1249     }
1250     putc(code, f);
1251     if (buf != NULL) {
1252         putc(nb >> 8, f);
1253         putc(nb, f);
1254         fwrite(buf, nb, 1, f);
1255     }
1256     fflush(f);
1257     if (ferror(f)) {
1258         error("Error writing record file: %m");
1259         return 0;
1260     }
1261     return 1;
1262 }