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