libexec/getty/chat.c

   1 /*-
   2  * Copyright (c) 1997
   3  *      David L Nugent <davidn@blaze.net.au>.
   4  *      All rights reserved.
   5  *
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, is permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice immediately at the beginning of the file, without modification,
  12  *    this list of conditions, and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. This work was done expressly for inclusion into FreeBSD.  Other use
  17  *    is permitted provided this notation is included.
  18  * 4. Absolutely no warranty of function or purpose is made by the authors.
  19  * 5. Modifications may be freely made to this file providing the above
  20  *    conditions are met.
  21  *
  22  * Modem chat module - send/expect style functions for getty
  23  * For semi-intelligent modem handling.
  24  *
  25  * $FreeBSD: src/libexec/getty/chat.c,v 1.6 1999/08/28 00:09:34 peter Exp $
  26  * $DragonFly: src/libexec/getty/chat.c,v 1.3 2003/11/14 03:54:30 dillon Exp $
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/stat.h>
  31 #include <sys/ioctl.h>
  32 #include <sys/resource.h>
  33 #include <sys/ttydefaults.h>
  34 #include <sys/utsname.h>
  35 #include <ctype.h>
  36 #include <errno.h>
  37 #include <fcntl.h>
  38 #include <libutil.h>
  39 #include <locale.h>
  40 #include <setjmp.h>
  41 #include <signal.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <syslog.h>
  45 #include <time.h>
  46 #include <termios.h>
  47 #include <unistd.h>
  48 #include <sys/socket.h>
  49
  50 #include "extern.h"
  51
  52 #define PAUSE_CH                (unsigned char)'\xff'   /* pause kludge */
  53
  54 #define CHATDEBUG_RECEIVE       0x01
  55 #define CHATDEBUG_SEND          0x02
  56 #define CHATDEBUG_EXPECT        0x04
  57 #define CHATDEBUG_MISC          0x08
  58
  59 #define CHATDEBUG_DEFAULT       0
  60 #define CHAT_DEFAULT_TIMEOUT    10
  61
  62
  63 static int chat_debug = CHATDEBUG_DEFAULT;
  64 static int chat_alarm = CHAT_DEFAULT_TIMEOUT; /* Default */
  65
  66 static volatile int alarmed = 0;
  67
  68
  69 static void   chat_alrm (int);
  70 static int    chat_unalarm (void);
  71 static int    getdigit (unsigned char **, int, int);
  72 static char   **read_chat (char **);
  73 static char   *cleanchr (char **, unsigned char);
  74 static char   *cleanstr (const unsigned char *, int);
  75 static const char *result (int);
  76 static int    chat_expect (const char *);
  77 static int    chat_send (char const *);
  78
  79
  80 /*
  81  * alarm signal handler
  82  * handle timeouts in read/write
  83  * change stdin to non-blocking mode to prevent
  84  * possible hang in read().
  85  */
  86
  87 static void
  88 chat_alrm(signo)
  89         int signo;
  90 {
  91         int on = 1;
  92
  93         alarm(1);
  94         alarmed = 1;
  95         signal(SIGALRM, chat_alrm);
  96         ioctl(STDIN_FILENO, FIONBIO, &on);
  97 }
  98
  99
 100 /*
 101  * Turn back on blocking mode reset by chat_alrm()
 102  */
 103
 104 static int
 105 chat_unalarm()
 106 {
 107         int off = 0;
 108         return ioctl(STDIN_FILENO, FIONBIO, &off);
 109 }
 110
 111
 112 /*
 113  * convert a string of a given base (octal/hex) to binary
 114  */
 115
 116 static int
 117 getdigit(ptr, base, max)
 118         unsigned char **ptr;
 119         int base, max;
 120 {
 121         int i, val = 0;
 122         char * q;
 123
 124         static const char xdigits[] = "0123456789abcdef";
 125
 126         for (i = 0, q = *ptr; i++ < max; ++q) {
 127                 int sval;
 128                 const char * s = strchr(xdigits, tolower(*q));
 129
 130                 if (s == NULL || (sval = s - xdigits) >= base)
 131                         break;
 132                 val = (val * base) + sval;
 133         }
 134         *ptr = q;
 135         return val;
 136 }
 137
 138
 139 /*
 140  * read_chat()
 141  * Convert a whitespace delimtied string into an array
 142  * of strings, being expect/send pairs
 143  */
 144
 145 static char **
 146 read_chat(chatstr)
 147         char **chatstr;
 148 {
 149         char *str = *chatstr;
 150         char **res = NULL;
 151
 152         if (str != NULL) {
 153                 char *tmp = NULL;
 154                 int l;
 155
 156                 if ((l=strlen(str)) > 0 && (tmp=malloc(l + 1)) != NULL &&
 157                     (res=malloc((l / 2 + 1) * sizeof(char *))) != NULL) {
 158                         static char ws[] = " \t";
 159                         char * p;
 160
 161                         for (l = 0, p = strtok(strcpy(tmp, str), ws);
 162                              p != NULL;
 163                              p = strtok(NULL, ws))
 164                         {
 165                                 unsigned char *q, *r;
 166
 167                                 /* Read escapes */
 168                                 for (q = r = (unsigned char *)p; *r; ++q)
 169                                 {
 170                                         if (*q == '\\')
 171                                         {
 172                                                 /* handle special escapes */
 173                                                 switch (*++q)
 174                                                 {
 175                                                 case 'a': /* bell */
 176                                                         *r++ = '\a';
 177                                                         break;
 178                                                 case 'r': /* cr */
 179                                                         *r++ = '\r';
 180                                                         break;
 181                                                 case 'n': /* nl */
 182                                                         *r++ = '\n';
 183                                                         break;
 184                                                 case 'f': /* ff */
 185                                                         *r++ = '\f';
 186                                                         break;
 187                                                 case 'b': /* bs */
 188                                                         *r++ = '\b';
 189                                                         break;
 190                                                 case 'e': /* esc */
 191                                                         *r++ = 27;
 192                                                         break;
 193                                                 case 't': /* tab */
 194                                                         *r++ = '\t';
 195                                                         break;
 196                                                 case 'p': /* pause */
 197                                                         *r++ = PAUSE_CH;
 198                                                         break;
 199                                                 case 's':
 200                                                 case 'S': /* space */
 201                                                         *r++ = ' ';
 202                                                         break;
 203                                                 case 'x': /* hexdigit */
 204                                                         ++q;
 205                                                         *r++ = getdigit(&q, 16, 2);
 206                                                         --q;
 207                                                         break;
 208                                                 case '0': /* octal */
 209                                                         ++q;
 210                                                         *r++ = getdigit(&q, 8, 3);
 211                                                         --q;
 212                                                         break;
 213                                                 default: /* literal */
 214                                                         *r++ = *q;
 215                                                         break;
 216                                                 case 0: /* not past eos */
 217                                                         --q;
 218                                                         break;
 219                                                 }
 220                                         } else {
 221                                                 /* copy standard character */
 222                                                 *r++ = *q;
 223                                         }
 224                                 }
 225
 226                                 /* Remove surrounding quotes, if any
 227                                  */
 228                                 if (*p == '"' || *p == '\'') {
 229                                         q = strrchr(p+1, *p);
 230                                         if (q != NULL && *q == *p && q[1] == '\0') {
 231                                                 *q = '\0';
 232                                                 strcpy(p, p+1);
 233                                         }
 234                                 }
 235
 236                                 res[l++] = p;
 237                         }
 238                         res[l] = NULL;
 239                         *chatstr = tmp;
 240                         return res;
 241                 }
 242                 free(tmp);
 243         }
 244         return res;
 245 }
 246
 247
 248 /*
 249  * clean a character for display (ctrl/meta character)
 250  */
 251
 252 static char *
 253 cleanchr(buf, ch)
 254         char **buf;
 255         unsigned char ch;
 256 {
 257         int l;
 258         static char tmpbuf[5];
 259         char * tmp = buf ? *buf : tmpbuf;
 260
 261         if (ch & 0x80) {
 262                 strcpy(tmp, "M-");
 263                 l = 2;
 264                 ch &= 0x7f;
 265         } else
 266         l = 0;
 267
 268         if (ch < 32) {
 269                 tmp[l++] = '^';
 270                 tmp[l++] = ch + '@';
 271         } else if (ch == 127) {
 272                 tmp[l++] = '^';
 273                 tmp[l++] = '?';
 274         } else
 275                 tmp[l++] = ch;
 276         tmp[l] = '\0';
 277
 278         if (buf)
 279                 *buf = tmp + l;
 280         return tmp;
 281 }
 282
 283
 284 /*
 285  * clean a string for display (ctrl/meta characters)
 286  */
 287
 288 static char *
 289 cleanstr(s, l)
 290         const unsigned char *s;
 291         int l;
 292 {
 293         static unsigned char * tmp = NULL;
 294         static int tmplen = 0;
 295
 296         if (tmplen < l * 4 + 1)
 297                 tmp = realloc(tmp, tmplen = l * 4 + 1);
 298
 299         if (tmp == NULL) {
 300                 tmplen = 0;
 301                 return (char *)"(mem alloc error)";
 302         } else {
 303                 int i = 0;
 304                 char * p = tmp;
 305
 306                 while (i < l)
 307                         cleanchr(&p, s[i++]);
 308                 *p = '\0';
 309         }
 310
 311         return tmp;
 312 }
 313
 314
 315 /*
 316  * return result as an pseudo-english word
 317  */
 318
 319 static const char *
 320 result(r)
 321         int r;
 322 {
 323         static const char * results[] = {
 324                 "OK", "MEMERROR", "IOERROR", "TIMEOUT"
 325         };
 326         return results[r & 3];
 327 }
 328
 329
 330 /*
 331  * chat_expect()
 332  * scan input for an expected string
 333  */
 334
 335 static int
 336 chat_expect(str)
 337         const char *str;
 338 {
 339         int len, r = 0;
 340
 341         if (chat_debug & CHATDEBUG_EXPECT)
 342                 syslog(LOG_DEBUG, "chat_expect '%s'", cleanstr(str, strlen(str)));
 343
 344         if ((len = strlen(str)) > 0) {
 345                 int i = 0;
 346                 char * got;
 347
 348                 if ((got = malloc(len + 1)) == NULL)
 349                         r = 1;
 350                 else {
 351
 352                         memset(got, 0, len+1);
 353                         alarm(chat_alarm);
 354                         alarmed = 0;
 355
 356                         while (r == 0 && i < len) {
 357                                 if (alarmed)
 358                                         r = 3;
 359                                 else {
 360                                         unsigned char ch;
 361
 362                                         if (read(STDIN_FILENO, &ch, 1) == 1) {
 363
 364                                                 if (chat_debug & CHATDEBUG_RECEIVE)
 365                                                         syslog(LOG_DEBUG, "chat_recv '%s' m=%d",
 366                                                                 cleanchr(NULL, ch), i);
 367
 368                                                 if (ch == str[i])
 369                                                         got[i++] = ch;
 370                                                 else if (i > 0) {
 371                                                         int j = 1;
 372
 373                                                         /* See if we can resync on a
 374                                                          * partial match in our buffer
 375                                                          */
 376                                                         while (j < i && memcmp(got + j, str, i - j) != NULL)
 377                                                                 j++;
 378                                                         if (j < i)
 379                                                                 memcpy(got, got + j, i - j);
 380                                                         i -= j;
 381                                                 }
 382                                         } else
 383                                                 r = alarmed ? 3 : 2;
 384                                 }
 385                         }
 386                         alarm(0);
 387                         chat_unalarm();
 388                         alarmed = 0;
 389                         free(got);
 390                 }
 391         }
 392
 393         if (chat_debug & CHATDEBUG_EXPECT)
 394                 syslog(LOG_DEBUG, "chat_expect %s", result(r));
 395
 396         return r;
 397 }
 398
 399
 400 /*
 401  * chat_send()
 402  * send a chat string
 403  */
 404
 405 static int
 406 chat_send(str)
 407         char const *str;
 408 {
 409         int r = 0;
 410
 411         if (chat_debug && CHATDEBUG_SEND)
 412                 syslog(LOG_DEBUG, "chat_send '%s'", cleanstr(str, strlen(str)));
 413
 414         if (*str) {
 415                 alarm(chat_alarm);
 416                 alarmed = 0;
 417                 while (r == 0 && *str)
 418                 {
 419                         unsigned char ch = (unsigned char)*str++;
 420
 421                         if (alarmed)
 422                                 r = 3;
 423                         else if (ch == PAUSE_CH)
 424                                 usleep(500000); /* 1/2 second */
 425                         else  {
 426                                 usleep(10000);  /* be kind to modem */
 427                                 if (write(STDOUT_FILENO, &ch, 1) != 1)
 428                                         r = alarmed ? 3 : 2;
 429                         }
 430                 }
 431                 alarm(0);
 432                 chat_unalarm();
 433                 alarmed = 0;
 434         }
 435
 436         if (chat_debug & CHATDEBUG_SEND)
 437           syslog(LOG_DEBUG, "chat_send %s", result(r));
 438
 439         return r;
 440 }
 441
 442
 443 /*
 444  * getty_chat()
 445  *
 446  * Termination codes:
 447  * -1 - no script supplied
 448  *  0 - script terminated correctly
 449  *  1 - invalid argument, expect string too large, etc.
 450  *  2 - error on an I/O operation or fatal error condition
 451  *  3 - timeout waiting for a simple string
 452  *
 453  * Parameters:
 454  *  char *scrstr     - unparsed chat script
 455  *  timeout          - seconds timeout
 456  *  debug            - debug value (bitmask)
 457  */
 458
 459 int
 460 getty_chat(scrstr, timeout, debug)
 461         char *scrstr;
 462         int timeout, debug;
 463 {
 464         int r = -1;
 465
 466         chat_alarm = timeout ? timeout : CHAT_DEFAULT_TIMEOUT;
 467         chat_debug = debug;
 468
 469         if (scrstr != NULL) {
 470                 char **script;
 471
 472                 if (chat_debug & CHATDEBUG_MISC)
 473                         syslog(LOG_DEBUG, "getty_chat script='%s'", scrstr);
 474
 475                 if ((script = read_chat(&scrstr)) != NULL) {
 476                         int i = r = 0;
 477                         int off = 0;
 478                         sig_t old_alarm;
 479
 480                         /*
 481                          * We need to be in raw mode for all this
 482                          * Rely on caller...
 483                          */
 484
 485                         old_alarm = signal(SIGALRM, chat_alrm);
 486                         chat_unalarm(); /* Force blocking mode at start */
 487
 488                         /*
 489                          * This is the send/expect loop
 490                          */
 491                         while (r == 0 && script[i] != NULL)
 492                                 if ((r = chat_expect(script[i++])) == 0 && script[i] != NULL)
 493                                         r = chat_send(script[i++]);
 494
 495                         signal(SIGALRM, old_alarm);
 496                         free(script);
 497                         free(scrstr);
 498
 499                         /*
 500                          * Ensure stdin is in blocking mode
 501                          */
 502                         ioctl(STDIN_FILENO, FIONBIO, &off);
 503                 }
 504
 505                 if (chat_debug & CHATDEBUG_MISC)
 506                   syslog(LOG_DEBUG, "getty_chat %s", result(r));
 507
 508         }
 509         return r;
 510 }