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 1.5 2005/05/07 20:00:20 corecode 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 "gettytab.h"
  51 #include "extern.h"
  52
  53 #define PAUSE_CH                (unsigned char)'\xff'   /* pause kludge */
  54
  55 #define CHATDEBUG_RECEIVE       0x01
  56 #define CHATDEBUG_SEND          0x02
  57 #define CHATDEBUG_EXPECT        0x04
  58 #define CHATDEBUG_MISC          0x08
  59
  60 #define CHATDEBUG_DEFAULT       0
  61 #define CHAT_DEFAULT_TIMEOUT    10
  62
  63
  64 static int chat_debug = CHATDEBUG_DEFAULT;
  65 static int chat_alarm = CHAT_DEFAULT_TIMEOUT; /* Default */
  66
  67 static volatile int alarmed = 0;
  68
  69
  70 static void   chat_alrm (int);
  71 static int    chat_unalarm (void);
  72 static int    getdigit (unsigned char **, int, int);
  73 static char   **read_chat (char **);
  74 static char   *cleanchr (char **, unsigned char);
  75 static char   *cleanstr (const unsigned char *, int);
  76 static const char *result (int);
  77 static int    chat_expect (const char *);
  78 static int    chat_send (char const *);
  79
  80
  81 /*
  82  * alarm signal handler
  83  * handle timeouts in read/write
  84  * change stdin to non-blocking mode to prevent
  85  * possible hang in read().
  86  */
  87
  88 static void
  89 chat_alrm(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(void)
 106 {
 107         int off = 0;
 108
 109         return ioctl(STDIN_FILENO, FIONBIO, &off);
 110 }
 111
 112
 113 /*
 114  * convert a string of a given base (octal/hex) to binary
 115  */
 116
 117 static int
 118 getdigit(unsigned char **ptr, int base, int max)
 119 {
 120         int i, val = 0;
 121         char * q;
 122
 123         static const char xdigits[] = "0123456789abcdef";
 124
 125         for (i = 0, q = *ptr; i++ < max; ++q) {
 126                 int sval;
 127                 const char * s = strchr(xdigits, tolower(*q));
 128
 129                 if (s == NULL || (sval = s - xdigits) >= base)
 130                         break;
 131                 val = (val * base) + sval;
 132         }
 133         *ptr = q;
 134         return val;
 135 }
 136
 137
 138 /*
 139  * read_chat()
 140  * Convert a whitespace delimtied string into an array
 141  * of strings, being expect/send pairs
 142  */
 143
 144 static char **
 145 read_chat(char **chatstr)
 146 {
 147         char *str = *chatstr;
 148         char **res = NULL;
 149
 150         if (str != NULL) {
 151                 char *tmp = NULL;
 152                 int l;
 153
 154                 if ((l=strlen(str)) > 0 && (tmp=malloc(l + 1)) != NULL &&
 155                     (res=malloc((l / 2 + 1) * sizeof(char *))) != NULL) {
 156                         static char ws[] = " \t";
 157                         char * p;
 158
 159                         for (l = 0, p = strtok(strcpy(tmp, str), ws);
 160                              p != NULL;
 161                              p = strtok(NULL, ws))
 162                         {
 163                                 unsigned char *q, *r;
 164
 165                                 /* Read escapes */
 166                                 for (q = r = (unsigned char *)p; *r; ++q)
 167                                 {
 168                                         if (*q == '\\')
 169                                         {
 170                                                 /* handle special escapes */
 171                                                 switch (*++q)
 172                                                 {
 173                                                 case 'a': /* bell */
 174                                                         *r++ = '\a';
 175                                                         break;
 176                                                 case 'r': /* cr */
 177                                                         *r++ = '\r';
 178                                                         break;
 179                                                 case 'n': /* nl */
 180                                                         *r++ = '\n';
 181                                                         break;
 182                                                 case 'f': /* ff */
 183                                                         *r++ = '\f';
 184                                                         break;
 185                                                 case 'b': /* bs */
 186                                                         *r++ = '\b';
 187                                                         break;
 188                                                 case 'e': /* esc */
 189                                                         *r++ = 27;
 190                                                         break;
 191                                                 case 't': /* tab */
 192                                                         *r++ = '\t';
 193                                                         break;
 194                                                 case 'p': /* pause */
 195                                                         *r++ = PAUSE_CH;
 196                                                         break;
 197                                                 case 's':
 198                                                 case 'S': /* space */
 199                                                         *r++ = ' ';
 200                                                         break;
 201                                                 case 'x': /* hexdigit */
 202                                                         ++q;
 203                                                         *r++ = getdigit(&q, 16, 2);
 204                                                         --q;
 205                                                         break;
 206                                                 case '0': /* octal */
 207                                                         ++q;
 208                                                         *r++ = getdigit(&q, 8, 3);
 209                                                         --q;
 210                                                         break;
 211                                                 default: /* literal */
 212                                                         *r++ = *q;
 213                                                         break;
 214                                                 case 0: /* not past eos */
 215                                                         --q;
 216                                                         break;
 217                                                 }
 218                                         } else {
 219                                                 /* copy standard character */
 220                                                 *r++ = *q;
 221                                         }
 222                                 }
 223
 224                                 /* Remove surrounding quotes, if any
 225                                  */
 226                                 if (*p == '"' || *p == '\'') {
 227                                         q = strrchr(p+1, *p);
 228                                         if (q != NULL && *q == *p && q[1] == '\0') {
 229                                                 *q = '\0';
 230                                                 strcpy(p, p+1);
 231                                         }
 232                                 }
 233
 234                                 res[l++] = p;
 235                         }
 236                         res[l] = NULL;
 237                         *chatstr = tmp;
 238                         return res;
 239                 }
 240                 free(tmp);
 241         }
 242         return res;
 243 }
 244
 245
 246 /*
 247  * clean a character for display (ctrl/meta character)
 248  */
 249
 250 static char *
 251 cleanchr(char **buf, unsigned char ch)
 252 {
 253         int l;
 254         static char tmpbuf[5];
 255         char * tmp = buf ? *buf : tmpbuf;
 256
 257         if (ch & 0x80) {
 258                 strcpy(tmp, "M-");
 259                 l = 2;
 260                 ch &= 0x7f;
 261         } else
 262         l = 0;
 263
 264         if (ch < 32) {
 265                 tmp[l++] = '^';
 266                 tmp[l++] = ch + '@';
 267         } else if (ch == 127) {
 268                 tmp[l++] = '^';
 269                 tmp[l++] = '?';
 270         } else
 271                 tmp[l++] = ch;
 272         tmp[l] = '\0';
 273
 274         if (buf)
 275                 *buf = tmp + l;
 276         return tmp;
 277 }
 278
 279
 280 /*
 281  * clean a string for display (ctrl/meta characters)
 282  */
 283
 284 static char *
 285 cleanstr(const unsigned char *s, int l)
 286 {
 287         static unsigned char * tmp = NULL;
 288         static int tmplen = 0;
 289
 290         if (tmplen < l * 4 + 1)
 291                 tmp = realloc(tmp, tmplen = l * 4 + 1);
 292
 293         if (tmp == NULL) {
 294                 tmplen = 0;
 295                 return (char *)"(mem alloc error)";
 296         } else {
 297                 int i = 0;
 298                 char * p = tmp;
 299
 300                 while (i < l)
 301                         cleanchr(&p, s[i++]);
 302                 *p = '\0';
 303         }
 304
 305         return tmp;
 306 }
 307
 308
 309 /*
 310  * return result as an pseudo-english word
 311  */
 312
 313 static const char *
 314 result(int r)
 315 {
 316         static const char * results[] = {
 317                 "OK", "MEMERROR", "IOERROR", "TIMEOUT"
 318         };
 319         return results[r & 3];
 320 }
 321
 322
 323 /*
 324  * chat_expect()
 325  * scan input for an expected string
 326  */
 327
 328 static int
 329 chat_expect(const char *str)
 330 {
 331         int len, r = 0;
 332
 333         if (chat_debug & CHATDEBUG_EXPECT)
 334                 syslog(LOG_DEBUG, "chat_expect '%s'", cleanstr(str, strlen(str)));
 335
 336         if ((len = strlen(str)) > 0) {
 337                 int i = 0;
 338                 char * got;
 339
 340                 if ((got = malloc(len + 1)) == NULL)
 341                         r = 1;
 342                 else {
 343
 344                         memset(got, 0, len+1);
 345                         alarm(chat_alarm);
 346                         alarmed = 0;
 347
 348                         while (r == 0 && i < len) {
 349                                 if (alarmed)
 350                                         r = 3;
 351                                 else {
 352                                         unsigned char ch;
 353
 354                                         if (read(STDIN_FILENO, &ch, 1) == 1) {
 355
 356                                                 if (chat_debug & CHATDEBUG_RECEIVE)
 357                                                         syslog(LOG_DEBUG, "chat_recv '%s' m=%d",
 358                                                                 cleanchr(NULL, ch), i);
 359
 360                                                 if (ch == str[i])
 361                                                         got[i++] = ch;
 362                                                 else if (i > 0) {
 363                                                         int j = 1;
 364
 365                                                         /* See if we can resync on a
 366                                                          * partial match in our buffer
 367                                                          */
 368                                                         while (j < i && memcmp(got + j, str, i - j) != NULL)
 369                                                                 j++;
 370                                                         if (j < i)
 371                                                                 memcpy(got, got + j, i - j);
 372                                                         i -= j;
 373                                                 }
 374                                         } else
 375                                                 r = alarmed ? 3 : 2;
 376                                 }
 377                         }
 378                         alarm(0);
 379                         chat_unalarm();
 380                         alarmed = 0;
 381                         free(got);
 382                 }
 383         }
 384
 385         if (chat_debug & CHATDEBUG_EXPECT)
 386                 syslog(LOG_DEBUG, "chat_expect %s", result(r));
 387
 388         return r;
 389 }
 390
 391
 392 /*
 393  * chat_send()
 394  * send a chat string
 395  */
 396
 397 static int
 398 chat_send(char const *str)
 399 {
 400         int r = 0;
 401
 402         if (chat_debug && CHATDEBUG_SEND)
 403                 syslog(LOG_DEBUG, "chat_send '%s'", cleanstr(str, strlen(str)));
 404
 405         if (*str) {
 406                 alarm(chat_alarm);
 407                 alarmed = 0;
 408                 while (r == 0 && *str)
 409                 {
 410                         unsigned char ch = (unsigned char)*str++;
 411
 412                         if (alarmed)
 413                                 r = 3;
 414                         else if (ch == PAUSE_CH)
 415                                 usleep(500000); /* 1/2 second */
 416                         else  {
 417                                 usleep(10000);  /* be kind to modem */
 418                                 if (write(STDOUT_FILENO, &ch, 1) != 1)
 419                                         r = alarmed ? 3 : 2;
 420                         }
 421                 }
 422                 alarm(0);
 423                 chat_unalarm();
 424                 alarmed = 0;
 425         }
 426
 427         if (chat_debug & CHATDEBUG_SEND)
 428           syslog(LOG_DEBUG, "chat_send %s", result(r));
 429
 430         return r;
 431 }
 432
 433
 434 /*
 435  * getty_chat()
 436  *
 437  * Termination codes:
 438  * -1 - no script supplied
 439  *  0 - script terminated correctly
 440  *  1 - invalid argument, expect string too large, etc.
 441  *  2 - error on an I/O operation or fatal error condition
 442  *  3 - timeout waiting for a simple string
 443  *
 444  * Parameters:
 445  *  char *scrstr     - unparsed chat script
 446  *  timeout          - seconds timeout
 447  *  debug            - debug value (bitmask)
 448  */
 449
 450 int
 451 getty_chat(char *scrstr, int timeout, int debug)
 452 {
 453         int r = -1;
 454
 455         chat_alarm = timeout ? timeout : CHAT_DEFAULT_TIMEOUT;
 456         chat_debug = debug;
 457
 458         if (scrstr != NULL) {
 459                 char **script;
 460
 461                 if (chat_debug & CHATDEBUG_MISC)
 462                         syslog(LOG_DEBUG, "getty_chat script='%s'", scrstr);
 463
 464                 if ((script = read_chat(&scrstr)) != NULL) {
 465                         int i = r = 0;
 466                         int off = 0;
 467                         sig_t old_alarm;
 468
 469                         /*
 470                          * We need to be in raw mode for all this
 471                          * Rely on caller...
 472                          */
 473
 474                         old_alarm = signal(SIGALRM, chat_alrm);
 475                         chat_unalarm(); /* Force blocking mode at start */
 476
 477                         /*
 478                          * This is the send/expect loop
 479                          */
 480                         while (r == 0 && script[i] != NULL)
 481                                 if ((r = chat_expect(script[i++])) == 0 && script[i] != NULL)
 482                                         r = chat_send(script[i++]);
 483
 484                         signal(SIGALRM, old_alarm);
 485                         free(script);
 486                         free(scrstr);
 487
 488                         /*
 489                          * Ensure stdin is in blocking mode
 490                          */
 491                         ioctl(STDIN_FILENO, FIONBIO, &off);
 492                 }
 493
 494                 if (chat_debug & CHATDEBUG_MISC)
 495                   syslog(LOG_DEBUG, "getty_chat %s", result(r));
 496
 497         }
 498         return r;
 499 }