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: head/libexec/getty/chat.c 329724 2018-02-21 15:57:24Z trasz $
  26  */
  27
  28 #include <sys/types.h>
  29 #include <sys/ioctl.h>
  30 #include <sys/utsname.h>
  31
  32 #include <ctype.h>
  33 #include <signal.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <syslog.h>
  37 #include <unistd.h>
  38
  39 #include "gettytab.h"
  40 #include "extern.h"
  41
  42 #define PAUSE_CH                (unsigned char)'\xff'   /* pause kludge */
  43
  44 #define CHATDEBUG_RECEIVE       0x01
  45 #define CHATDEBUG_SEND          0x02
  46 #define CHATDEBUG_EXPECT        0x04
  47 #define CHATDEBUG_MISC          0x08
  48
  49 #define CHATDEBUG_DEFAULT       0
  50 #define CHAT_DEFAULT_TIMEOUT    10
  51
  52
  53 static int chat_debug = CHATDEBUG_DEFAULT;
  54 static int chat_alarm = CHAT_DEFAULT_TIMEOUT; /* Default */
  55
  56 static volatile int alarmed = 0;
  57
  58
  59 static void   chat_alrm(int);
  60 static int    chat_unalarm(void);
  61 static int    getdigit(unsigned char **, int, int);
  62 static char   **read_chat(char **);
  63 static char   *cleanchr(char **, unsigned char);
  64 static const char *cleanstr(const unsigned char *, int);
  65 static const char *result(int);
  66 static int    chat_expect(const char *);
  67 static int    chat_send(char const *);
  68
  69
  70 /*
  71  * alarm signal handler
  72  * handle timeouts in read/write
  73  * change stdin to non-blocking mode to prevent
  74  * possible hang in read().
  75  */
  76
  77 static void
  78 chat_alrm(int signo __unused)
  79 {
  80         int on = 1;
  81
  82         alarm(1);
  83         alarmed = 1;
  84         signal(SIGALRM, chat_alrm);
  85         ioctl(STDIN_FILENO, FIONBIO, &on);
  86 }
  87
  88
  89 /*
  90  * Turn back on blocking mode reset by chat_alrm()
  91  */
  92
  93 static int
  94 chat_unalarm(void)
  95 {
  96         int off = 0;
  97
  98         return ioctl(STDIN_FILENO, FIONBIO, &off);
  99 }
 100
 101
 102 /*
 103  * convert a string of a given base (octal/hex) to binary
 104  */
 105
 106 static int
 107 getdigit(unsigned char **ptr, int base, int max)
 108 {
 109         int i, val = 0;
 110         char * q;
 111
 112         static const char xdigits[] = "0123456789abcdef";
 113
 114         for (i = 0, q = *ptr; i++ < max; ++q) {
 115                 int sval;
 116                 const char * s = strchr(xdigits, tolower(*q));
 117
 118                 if (s == NULL || (sval = s - xdigits) >= base)
 119                         break;
 120                 val = (val * base) + sval;
 121         }
 122         *ptr = q;
 123         return val;
 124 }
 125
 126
 127 /*
 128  * read_chat()
 129  * Convert a whitespace delimtied string into an array
 130  * of strings, being expect/send pairs
 131  */
 132
 133 static char **
 134 read_chat(char **chatstr)
 135 {
 136         char *str = *chatstr;
 137         char **res = NULL;
 138
 139         if (str != NULL) {
 140                 char *tmp = NULL;
 141                 int l;
 142
 143                 if ((l=strlen(str)) > 0 && (tmp=malloc(l + 1)) != NULL &&
 144                     (res=malloc((l / 2 + 1) * sizeof(char *))) != NULL) {
 145                         static char ws[] = " \t";
 146                         char * p;
 147
 148                         for (l = 0, p = strtok(strcpy(tmp, str), ws);
 149                              p != NULL;
 150                              p = strtok(NULL, ws))
 151                         {
 152                                 unsigned char *q, *r;
 153
 154                                 /* Read escapes */
 155                                 for (q = r = (unsigned char *)p; *r; ++q)
 156                                 {
 157                                         if (*q == '\\')
 158                                         {
 159                                                 /* handle special escapes */
 160                                                 switch (*++q)
 161                                                 {
 162                                                 case 'a': /* bell */
 163                                                         *r++ = '\a';
 164                                                         break;
 165                                                 case 'r': /* cr */
 166                                                         *r++ = '\r';
 167                                                         break;
 168                                                 case 'n': /* nl */
 169                                                         *r++ = '\n';
 170                                                         break;
 171                                                 case 'f': /* ff */
 172                                                         *r++ = '\f';
 173                                                         break;
 174                                                 case 'b': /* bs */
 175                                                         *r++ = '\b';
 176                                                         break;
 177                                                 case 'e': /* esc */
 178                                                         *r++ = 27;
 179                                                         break;
 180                                                 case 't': /* tab */
 181                                                         *r++ = '\t';
 182                                                         break;
 183                                                 case 'p': /* pause */
 184                                                         *r++ = PAUSE_CH;
 185                                                         break;
 186                                                 case 's':
 187                                                 case 'S': /* space */
 188                                                         *r++ = ' ';
 189                                                         break;
 190                                                 case 'x': /* hexdigit */
 191                                                         ++q;
 192                                                         *r++ = getdigit(&q, 16, 2);
 193                                                         --q;
 194                                                         break;
 195                                                 case '0': /* octal */
 196                                                         ++q;
 197                                                         *r++ = getdigit(&q, 8, 3);
 198                                                         --q;
 199                                                         break;
 200                                                 default: /* literal */
 201                                                         *r++ = *q;
 202                                                         break;
 203                                                 case 0: /* not past eos */
 204                                                         --q;
 205                                                         break;
 206                                                 }
 207                                         } else {
 208                                                 /* copy standard character */
 209                                                 *r++ = *q;
 210                                         }
 211                                 }
 212
 213                                 /* Remove surrounding quotes, if any
 214                                  */
 215                                 if (*p == '"' || *p == '\'') {
 216                                         q = strrchr(p+1, *p);
 217                                         if (q != NULL && *q == *p && q[1] == '\0') {
 218                                                 *q = '\0';
 219                                                 strcpy(p, p+1);
 220                                         }
 221                                 }
 222
 223                                 res[l++] = p;
 224                         }
 225                         res[l] = NULL;
 226                         *chatstr = tmp;
 227                         return res;
 228                 }
 229                 free(tmp);
 230         }
 231         return res;
 232 }
 233
 234
 235 /*
 236  * clean a character for display (ctrl/meta character)
 237  */
 238
 239 static char *
 240 cleanchr(char **buf, unsigned char ch)
 241 {
 242         int l;
 243         static char tmpbuf[5];
 244         char * tmp = buf ? *buf : tmpbuf;
 245
 246         if (ch & 0x80) {
 247                 strcpy(tmp, "M-");
 248                 l = 2;
 249                 ch &= 0x7f;
 250         } else
 251         l = 0;
 252
 253         if (ch < 32) {
 254                 tmp[l++] = '^';
 255                 tmp[l++] = ch + '@';
 256         } else if (ch == 127) {
 257                 tmp[l++] = '^';
 258                 tmp[l++] = '?';
 259         } else
 260                 tmp[l++] = ch;
 261         tmp[l] = '\0';
 262
 263         if (buf)
 264                 *buf = tmp + l;
 265         return tmp;
 266 }
 267
 268
 269 /*
 270  * clean a string for display (ctrl/meta characters)
 271  */
 272
 273 static const char *
 274 cleanstr(const unsigned char *s, int l)
 275 {
 276         static unsigned char * tmp = NULL;
 277         static int tmplen = 0;
 278
 279         if (tmplen < l * 4 + 1)
 280                 tmp = realloc(tmp, tmplen = l * 4 + 1);
 281
 282         if (tmp == NULL) {
 283                 tmplen = 0;
 284                 return "(mem alloc error)";
 285         } else {
 286                 int i = 0;
 287                 char * p = tmp;
 288
 289                 while (i < l)
 290                         cleanchr(&p, s[i++]);
 291                 *p = '\0';
 292         }
 293
 294         return tmp;
 295 }
 296
 297
 298 /*
 299  * return result as a pseudo-english word
 300  */
 301
 302 static const char *
 303 result(int r)
 304 {
 305         static const char * results[] = {
 306                 "OK", "MEMERROR", "IOERROR", "TIMEOUT"
 307         };
 308         return results[r & 3];
 309 }
 310
 311
 312 /*
 313  * chat_expect()
 314  * scan input for an expected string
 315  */
 316
 317 static int
 318 chat_expect(const char *str)
 319 {
 320         int len, r = 0;
 321
 322         if (chat_debug & CHATDEBUG_EXPECT)
 323                 syslog(LOG_DEBUG, "chat_expect '%s'", cleanstr(str, strlen(str)));
 324
 325         if ((len = strlen(str)) > 0) {
 326                 int i = 0;
 327                 char * got;
 328
 329                 if ((got = malloc(len + 1)) == NULL)
 330                         r = 1;
 331                 else {
 332
 333                         memset(got, 0, len+1);
 334                         alarm(chat_alarm);
 335                         alarmed = 0;
 336
 337                         while (r == 0 && i < len) {
 338                                 if (alarmed)
 339                                         r = 3;
 340                                 else {
 341                                         unsigned char ch;
 342
 343                                         if (read(STDIN_FILENO, &ch, 1) == 1) {
 344
 345                                                 if (chat_debug & CHATDEBUG_RECEIVE)
 346                                                         syslog(LOG_DEBUG, "chat_recv '%s' m=%d",
 347                                                                 cleanchr(NULL, ch), i);
 348
 349                                                 if (ch == str[i])
 350                                                         got[i++] = ch;
 351                                                 else if (i > 0) {
 352                                                         int j = 1;
 353
 354                                                         /* See if we can resync on a
 355                                                          * partial match in our buffer
 356                                                          */
 357                                                         while (j < i && memcmp(got + j, str, i - j) != 0)
 358                                                                 j++;
 359                                                         if (j < i)
 360                                                                 memcpy(got, got + j, i - j);
 361                                                         i -= j;
 362                                                 }
 363                                         } else
 364                                                 r = alarmed ? 3 : 2;
 365                                 }
 366                         }
 367                         alarm(0);
 368                         chat_unalarm();
 369                         alarmed = 0;
 370                         free(got);
 371                 }
 372         }
 373
 374         if (chat_debug & CHATDEBUG_EXPECT)
 375                 syslog(LOG_DEBUG, "chat_expect %s", result(r));
 376
 377         return r;
 378 }
 379
 380
 381 /*
 382  * chat_send()
 383  * send a chat string
 384  */
 385
 386 static int
 387 chat_send(char const *str)
 388 {
 389         int r = 0;
 390
 391         if (chat_debug & CHATDEBUG_SEND)
 392                 syslog(LOG_DEBUG, "chat_send '%s'", cleanstr(str, strlen(str)));
 393
 394         if (*str) {
 395                 alarm(chat_alarm);
 396                 alarmed = 0;
 397                 while (r == 0 && *str)
 398                 {
 399                         unsigned char ch = (unsigned char)*str++;
 400
 401                         if (alarmed)
 402                                 r = 3;
 403                         else if (ch == PAUSE_CH)
 404                                 usleep(500000); /* 1/2 second */
 405                         else  {
 406                                 usleep(10000);  /* be kind to modem */
 407                                 if (write(STDOUT_FILENO, &ch, 1) != 1)
 408                                         r = alarmed ? 3 : 2;
 409                         }
 410                 }
 411                 alarm(0);
 412                 chat_unalarm();
 413                 alarmed = 0;
 414         }
 415
 416         if (chat_debug & CHATDEBUG_SEND)
 417           syslog(LOG_DEBUG, "chat_send %s", result(r));
 418
 419         return r;
 420 }
 421
 422
 423 /*
 424  * getty_chat()
 425  *
 426  * Termination codes:
 427  * -1 - no script supplied
 428  *  0 - script terminated correctly
 429  *  1 - invalid argument, expect string too large, etc.
 430  *  2 - error on an I/O operation or fatal error condition
 431  *  3 - timeout waiting for a simple string
 432  *
 433  * Parameters:
 434  *  char *scrstr     - unparsed chat script
 435  *  timeout          - seconds timeout
 436  *  debug            - debug value (bitmask)
 437  */
 438
 439 int
 440 getty_chat(char *scrstr, int timeout, int debug)
 441 {
 442         int r = -1;
 443
 444         chat_alarm = timeout ? timeout : CHAT_DEFAULT_TIMEOUT;
 445         chat_debug = debug;
 446
 447         if (scrstr != NULL) {
 448                 char **script;
 449
 450                 if (chat_debug & CHATDEBUG_MISC)
 451                         syslog(LOG_DEBUG, "getty_chat script='%s'", scrstr);
 452
 453                 if ((script = read_chat(&scrstr)) != NULL) {
 454                         int i = r = 0;
 455                         int off = 0;
 456                         sig_t old_alarm;
 457
 458                         /*
 459                          * We need to be in raw mode for all this
 460                          * Rely on caller...
 461                          */
 462
 463                         old_alarm = signal(SIGALRM, chat_alrm);
 464                         chat_unalarm(); /* Force blocking mode at start */
 465
 466                         /*
 467                          * This is the send/expect loop
 468                          */
 469                         while (r == 0 && script[i] != NULL)
 470                                 if ((r = chat_expect(script[i++])) == 0 && script[i] != NULL)
 471                                         r = chat_send(script[i++]);
 472
 473                         signal(SIGALRM, old_alarm);
 474                         free(script);
 475                         free(scrstr);
 476
 477                         /*
 478                          * Ensure stdin is in blocking mode
 479                          */
 480                         ioctl(STDIN_FILENO, FIONBIO, &off);
 481                 }
 482
 483                 if (chat_debug & CHATDEBUG_MISC)
 484                   syslog(LOG_DEBUG, "getty_chat %s", result(r));
 485
 486         }
 487         return r;
 488 }