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