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 1.4 2004/03/26 00:30:12 cpressey 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(int signo)
  89 {
  90         int on = 1;
  91
  92         alarm(1);
  93         alarmed = 1;
  94         signal(SIGALRM, chat_alrm);
  95         ioctl(STDIN_FILENO, FIONBIO, &on);
  96 }
  97
  98
  99 /*
 100  * Turn back on blocking mode reset by chat_alrm()
 101  */
 102
 103 static int
 104 chat_unalarm(void)
 105 {
 106         int off = 0;
 107
 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(unsigned char **ptr, int base, int max)
 118 {
 119         int i, val = 0;
 120         char * q;
 121
 122         static const char xdigits[] = "0123456789abcdef";
 123
 124         for (i = 0, q = *ptr; i++ < max; ++q) {
 125                 int sval;
 126                 const char * s = strchr(xdigits, tolower(*q));
 127
 128                 if (s == NULL || (sval = s - xdigits) >= base)
 129                         break;
 130                 val = (val * base) + sval;
 131         }
 132         *ptr = q;
 133         return val;
 134 }
 135
 136
 137 /*
 138  * read_chat()
 139  * Convert a whitespace delimtied string into an array
 140  * of strings, being expect/send pairs
 141  */
 142
 143 static char **
 144 read_chat(char **chatstr)
 145 {
 146         char *str = *chatstr;
 147         char **res = NULL;
 148
 149         if (str != NULL) {
 150                 char *tmp = NULL;
 151                 int l;
 152
 153                 if ((l=strlen(str)) > 0 && (tmp=malloc(l + 1)) != NULL &&
 154                     (res=malloc((l / 2 + 1) * sizeof(char *))) != NULL) {
 155                         static char ws[] = " \t";
 156                         char * p;
 157
 158                         for (l = 0, p = strtok(strcpy(tmp, str), ws);
 159                              p != NULL;
 160                              p = strtok(NULL, ws))
 161                         {
 162                                 unsigned char *q, *r;
 163
 164                                 /* Read escapes */
 165                                 for (q = r = (unsigned char *)p; *r; ++q)
 166                                 {
 167                                         if (*q == '\\')
 168                                         {
 169                                                 /* handle special escapes */
 170                                                 switch (*++q)
 171                                                 {
 172                                                 case 'a': /* bell */
 173                                                         *r++ = '\a';
 174                                                         break;
 175                                                 case 'r': /* cr */
 176                                                         *r++ = '\r';
 177                                                         break;
 178                                                 case 'n': /* nl */
 179                                                         *r++ = '\n';
 180                                                         break;
 181                                                 case 'f': /* ff */
 182                                                         *r++ = '\f';
 183                                                         break;
 184                                                 case 'b': /* bs */
 185                                                         *r++ = '\b';
 186                                                         break;
 187                                                 case 'e': /* esc */
 188                                                         *r++ = 27;
 189                                                         break;
 190                                                 case 't': /* tab */
 191                                                         *r++ = '\t';
 192                                                         break;
 193                                                 case 'p': /* pause */
 194                                                         *r++ = PAUSE_CH;
 195                                                         break;
 196                                                 case 's':
 197                                                 case 'S': /* space */
 198                                                         *r++ = ' ';
 199                                                         break;
 200                                                 case 'x': /* hexdigit */
 201                                                         ++q;
 202                                                         *r++ = getdigit(&q, 16, 2);
 203                                                         --q;
 204                                                         break;
 205                                                 case '0': /* octal */
 206                                                         ++q;
 207                                                         *r++ = getdigit(&q, 8, 3);
 208                                                         --q;
 209                                                         break;
 210                                                 default: /* literal */
 211                                                         *r++ = *q;
 212                                                         break;
 213                                                 case 0: /* not past eos */
 214                                                         --q;
 215                                                         break;
 216                                                 }
 217                                         } else {
 218                                                 /* copy standard character */
 219                                                 *r++ = *q;
 220                                         }
 221                                 }
 222
 223                                 /* Remove surrounding quotes, if any
 224                                  */
 225                                 if (*p == '"' || *p == '\'') {
 226                                         q = strrchr(p+1, *p);
 227                                         if (q != NULL && *q == *p && q[1] == '\0') {
 228                                                 *q = '\0';
 229                                                 strcpy(p, p+1);
 230                                         }
 231                                 }
 232
 233                                 res[l++] = p;
 234                         }
 235                         res[l] = NULL;
 236                         *chatstr = tmp;
 237                         return res;
 238                 }
 239                 free(tmp);
 240         }
 241         return res;
 242 }
 243
 244
 245 /*
 246  * clean a character for display (ctrl/meta character)
 247  */
 248
 249 static char *
 250 cleanchr(char **buf, unsigned char ch)
 251 {
 252         int l;
 253         static char tmpbuf[5];
 254         char * tmp = buf ? *buf : tmpbuf;
 255
 256         if (ch & 0x80) {
 257                 strcpy(tmp, "M-");
 258                 l = 2;
 259                 ch &= 0x7f;
 260         } else
 261         l = 0;
 262
 263         if (ch < 32) {
 264                 tmp[l++] = '^';
 265                 tmp[l++] = ch + '@';
 266         } else if (ch == 127) {
 267                 tmp[l++] = '^';
 268                 tmp[l++] = '?';
 269         } else
 270                 tmp[l++] = ch;
 271         tmp[l] = '\0';
 272
 273         if (buf)
 274                 *buf = tmp + l;
 275         return tmp;
 276 }
 277
 278
 279 /*
 280  * clean a string for display (ctrl/meta characters)
 281  */
 282
 283 static char *
 284 cleanstr(const unsigned char *s, int l)
 285 {
 286         static unsigned char * tmp = NULL;
 287         static int tmplen = 0;
 288
 289         if (tmplen < l * 4 + 1)
 290                 tmp = realloc(tmp, tmplen = l * 4 + 1);
 291
 292         if (tmp == NULL) {
 293                 tmplen = 0;
 294                 return (char *)"(mem alloc error)";
 295         } else {
 296                 int i = 0;
 297                 char * p = tmp;
 298
 299                 while (i < l)
 300                         cleanchr(&p, s[i++]);
 301                 *p = '\0';
 302         }
 303
 304         return tmp;
 305 }
 306
 307
 308 /*
 309  * return result as an pseudo-english word
 310  */
 311
 312 static const char *
 313 result(int r)
 314 {
 315         static const char * results[] = {
 316                 "OK", "MEMERROR", "IOERROR", "TIMEOUT"
 317         };
 318         return results[r & 3];
 319 }
 320
 321
 322 /*
 323  * chat_expect()
 324  * scan input for an expected string
 325  */
 326
 327 static int
 328 chat_expect(const char *str)
 329 {
 330         int len, r = 0;
 331
 332         if (chat_debug & CHATDEBUG_EXPECT)
 333                 syslog(LOG_DEBUG, "chat_expect '%s'", cleanstr(str, strlen(str)));
 334
 335         if ((len = strlen(str)) > 0) {
 336                 int i = 0;
 337                 char * got;
 338
 339                 if ((got = malloc(len + 1)) == NULL)
 340                         r = 1;
 341                 else {
 342
 343                         memset(got, 0, len+1);
 344                         alarm(chat_alarm);
 345                         alarmed = 0;
 346
 347                         while (r == 0 && i < len) {
 348                                 if (alarmed)
 349                                         r = 3;
 350                                 else {
 351                                         unsigned char ch;
 352
 353                                         if (read(STDIN_FILENO, &ch, 1) == 1) {
 354
 355                                                 if (chat_debug & CHATDEBUG_RECEIVE)
 356                                                         syslog(LOG_DEBUG, "chat_recv '%s' m=%d",
 357                                                                 cleanchr(NULL, ch), i);
 358
 359                                                 if (ch == str[i])
 360                                                         got[i++] = ch;
 361                                                 else if (i > 0) {
 362                                                         int j = 1;
 363
 364                                                         /* See if we can resync on a
 365                                                          * partial match in our buffer
 366                                                          */
 367                                                         while (j < i && memcmp(got + j, str, i - j) != NULL)
 368                                                                 j++;
 369                                                         if (j < i)
 370                                                                 memcpy(got, got + j, i - j);
 371                                                         i -= j;
 372                                                 }
 373                                         } else
 374                                                 r = alarmed ? 3 : 2;
 375                                 }
 376                         }
 377                         alarm(0);
 378                         chat_unalarm();
 379                         alarmed = 0;
 380                         free(got);
 381                 }
 382         }
 383
 384         if (chat_debug & CHATDEBUG_EXPECT)
 385                 syslog(LOG_DEBUG, "chat_expect %s", result(r));
 386
 387         return r;
 388 }
 389
 390
 391 /*
 392  * chat_send()
 393  * send a chat string
 394  */
 395
 396 static int
 397 chat_send(char const *str)
 398 {
 399         int r = 0;
 400
 401         if (chat_debug && CHATDEBUG_SEND)
 402                 syslog(LOG_DEBUG, "chat_send '%s'", cleanstr(str, strlen(str)));
 403
 404         if (*str) {
 405                 alarm(chat_alarm);
 406                 alarmed = 0;
 407                 while (r == 0 && *str)
 408                 {
 409                         unsigned char ch = (unsigned char)*str++;
 410
 411                         if (alarmed)
 412                                 r = 3;
 413                         else if (ch == PAUSE_CH)
 414                                 usleep(500000); /* 1/2 second */
 415                         else  {
 416                                 usleep(10000);  /* be kind to modem */
 417                                 if (write(STDOUT_FILENO, &ch, 1) != 1)
 418                                         r = alarmed ? 3 : 2;
 419                         }
 420                 }
 421                 alarm(0);
 422                 chat_unalarm();
 423                 alarmed = 0;
 424         }
 425
 426         if (chat_debug & CHATDEBUG_SEND)
 427           syslog(LOG_DEBUG, "chat_send %s", result(r));
 428
 429         return r;
 430 }
 431
 432
 433 /*
 434  * getty_chat()
 435  *
 436  * Termination codes:
 437  * -1 - no script supplied
 438  *  0 - script terminated correctly
 439  *  1 - invalid argument, expect string too large, etc.
 440  *  2 - error on an I/O operation or fatal error condition
 441  *  3 - timeout waiting for a simple string
 442  *
 443  * Parameters:
 444  *  char *scrstr     - unparsed chat script
 445  *  timeout          - seconds timeout
 446  *  debug            - debug value (bitmask)
 447  */
 448
 449 int
 450 getty_chat(char *scrstr, int timeout, int debug)
 451 {
 452         int r = -1;
 453
 454         chat_alarm = timeout ? timeout : CHAT_DEFAULT_TIMEOUT;
 455         chat_debug = debug;
 456
 457         if (scrstr != NULL) {
 458                 char **script;
 459
 460                 if (chat_debug & CHATDEBUG_MISC)
 461                         syslog(LOG_DEBUG, "getty_chat script='%s'", scrstr);
 462
 463                 if ((script = read_chat(&scrstr)) != NULL) {
 464                         int i = r = 0;
 465                         int off = 0;
 466                         sig_t old_alarm;
 467
 468                         /*
 469                          * We need to be in raw mode for all this
 470                          * Rely on caller...
 471                          */
 472
 473                         old_alarm = signal(SIGALRM, chat_alrm);
 474                         chat_unalarm(); /* Force blocking mode at start */
 475
 476                         /*
 477                          * This is the send/expect loop
 478                          */
 479                         while (r == 0 && script[i] != NULL)
 480                                 if ((r = chat_expect(script[i++])) == 0 && script[i] != NULL)
 481                                         r = chat_send(script[i++]);
 482
 483                         signal(SIGALRM, old_alarm);
 484                         free(script);
 485                         free(scrstr);
 486
 487                         /*
 488                          * Ensure stdin is in blocking mode
 489                          */
 490                         ioctl(STDIN_FILENO, FIONBIO, &off);
 491                 }
 492
 493                 if (chat_debug & CHATDEBUG_MISC)
 494                   syslog(LOG_DEBUG, "getty_chat %s", result(r));
 495
 496         }
 497         return r;
 498 }