miscutils/chat.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * bare bones chat utility
   4  * inspired by ppp's chat
   5  *
   6  * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   7  *
   8  * Licensed under GPLv2, see file LICENSE in this tarball for details.
   9  */
  10 #include "libbb.h"
  11
  12 /*
  13 #define ENABLE_FEATURE_CHAT_NOFAIL              1 // +126 bytes
  14 #define ENABLE_FEATURE_CHAT_TTY_HIFI            0 // + 70 bytes
  15 #define ENABLE_FEATURE_CHAT_IMPLICIT_CR         1 // + 44 bytes
  16 #define ENABLE_FEATURE_CHAT_SEND_ESCAPES        0 // +103 bytes
  17 #define ENABLE_FEATURE_CHAT_VAR_ABORT_LEN       0 // + 70 bytes
  18 #define ENABLE_FEATURE_CHAT_CLR_ABORT           0 // +113 bytes
  19 #define ENABLE_FEATURE_CHAT_SWALLOW_OPTS        0 // + 23 bytes
  20 */
  21
  22 // default timeout: 45 sec
  23 #define DEFAULT_CHAT_TIMEOUT 45*1000
  24 // max length of "abort string",
  25 // i.e. device reply which causes termination
  26 #define MAX_ABORT_LEN 50
  27
  28 // possible exit codes
  29 enum {
  30         ERR_OK = 0,     // all's well
  31         ERR_MEM,        // read too much while expecting
  32         ERR_IO,         // signalled or I/O error
  33         ERR_TIMEOUT,    // timed out while expecting
  34         ERR_ABORT,      // first abort condition was met
  35 //      ERR_ABORT2,     // second abort condition was met
  36 //      ...
  37 };
  38
  39 // exit code
  40 // N.B> 10 bytes for volatile. Why all these signals?!
  41 static /*volatile*/ smallint exitcode;
  42
  43 // trap for critical signals
  44 static void signal_handler(UNUSED_PARAM int signo)
  45 {
  46         // report I/O error condition
  47         exitcode = ERR_IO;
  48 }
  49
  50 #if !ENABLE_FEATURE_CHAT_IMPLICIT_CR
  51 #define unescape(s, nocr) unescape(s)
  52 #endif
  53 static size_t unescape(char *s, int *nocr)
  54 {
  55         char *start = s;
  56         char *p = s;
  57
  58         while (*s) {
  59                 char c = *s;
  60                 // do we need special processing?
  61                 // standard escapes + \s for space and \N for \0
  62                 // \c inhibits terminating \r for commands and is noop for expects
  63                 if ('\\' == c) {
  64                         c = *++s;
  65                         if (c) {
  66 #if ENABLE_FEATURE_CHAT_IMPLICIT_CR
  67                                 if ('c' == c) {
  68                                         *nocr = 1;
  69                                         goto next;
  70                                 }
  71 #endif
  72                                 if ('N' == c) {
  73                                         c = '\0';
  74                                 } else if ('s' == c) {
  75                                         c = ' ';
  76 #if ENABLE_FEATURE_CHAT_NOFAIL
  77                                 // unescape leading dash only
  78                                 // TODO: and only for expect, not command string
  79                                 } else if ('-' == c && (start + 1 == s)) {
  80                                         //c = '-';
  81 #endif
  82                                 } else {
  83                                         c = bb_process_escape_sequence((const char **)&s);
  84                                         s--;
  85                                 }
  86                         }
  87                 // ^A becomes \001, ^B -- \002 and so on...
  88                 } else if ('^' == c) {
  89                         c = *++s-'@';
  90                 }
  91                 // put unescaped char
  92                 *p++ = c;
  93 #if ENABLE_FEATURE_CHAT_IMPLICIT_CR
  94  next:
  95 #endif
  96                 // next char
  97                 s++;
  98         }
  99         *p = '\0';
 100
 101         return p - start;
 102 }
 103
 104
 105 int chat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 106 int chat_main(int argc UNUSED_PARAM, char **argv)
 107 {
 108 // should we dump device output? to what fd? by default no.
 109 // this can be controlled later via ECHO {ON|OFF} chat directive
 110 //      int echo_fd;
 111         bool echo = 0;
 112         // collection of device replies which cause unconditional termination
 113         llist_t *aborts = NULL;
 114         // inactivity period
 115         int timeout = DEFAULT_CHAT_TIMEOUT;
 116         // maximum length of abort string
 117 #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 118         size_t max_abort_len = 0;
 119 #else
 120 #define max_abort_len MAX_ABORT_LEN
 121 #endif
 122 #if ENABLE_FEATURE_CHAT_TTY_HIFI
 123         struct termios tio0, tio;
 124 #endif
 125         // directive names
 126         enum {
 127                 DIR_HANGUP = 0,
 128                 DIR_ABORT,
 129 #if ENABLE_FEATURE_CHAT_CLR_ABORT
 130                 DIR_CLR_ABORT,
 131 #endif
 132                 DIR_TIMEOUT,
 133                 DIR_ECHO,
 134                 DIR_SAY,
 135         };
 136
 137         // make x* functions fail with correct exitcode
 138         xfunc_error_retval = ERR_IO;
 139
 140         // trap vanilla signals to prevent process from being killed suddenly
 141         bb_signals(0
 142                 + (1 << SIGHUP)
 143                 + (1 << SIGINT)
 144                 + (1 << SIGTERM)
 145                 + (1 << SIGPIPE)
 146                 , signal_handler);
 147
 148 #if ENABLE_FEATURE_CHAT_TTY_HIFI
 149         tcgetattr(STDIN_FILENO, &tio);
 150         tio0 = tio;
 151         cfmakeraw(&tio);
 152         tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio);
 153 #endif
 154
 155 #if ENABLE_FEATURE_CHAT_SWALLOW_OPTS
 156         getopt32(argv, "vVsSE");
 157         argv += optind;
 158 #else
 159         argv++; // goto first arg
 160 #endif
 161         // handle chat expect-send pairs
 162         while (*argv) {
 163                 // directive given? process it
 164                 int key = index_in_strings(
 165                         "HANGUP\0" "ABORT\0"
 166 #if ENABLE_FEATURE_CHAT_CLR_ABORT
 167                         "CLR_ABORT\0"
 168 #endif
 169                         "TIMEOUT\0" "ECHO\0" "SAY\0"
 170                         , *argv
 171                 );
 172                 if (key >= 0) {
 173                         // cache directive value
 174                         char *arg = *++argv;
 175                         // ON -> 1, anything else -> 0
 176                         bool onoff = !strcmp("ON", arg);
 177                         // process directive
 178                         if (DIR_HANGUP == key) {
 179                                 // turn SIGHUP on/off
 180                                 signal(SIGHUP, onoff ? signal_handler : SIG_IGN);
 181                         } else if (DIR_ABORT == key) {
 182                                 // append the string to abort conditions
 183 #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 184                                 size_t len = strlen(arg);
 185                                 if (len > max_abort_len)
 186                                         max_abort_len = len;
 187 #endif
 188                                 llist_add_to_end(&aborts, arg);
 189 #if ENABLE_FEATURE_CHAT_CLR_ABORT
 190                         } else if (DIR_CLR_ABORT == key) {
 191                                 // remove the string from abort conditions
 192                                 // N.B. gotta refresh maximum length too...
 193 #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 194                                 max_abort_len = 0;
 195 #endif
 196                                 for (llist_t *l = aborts; l; l = l->link) {
 197 #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 198                                         size_t len = strlen(l->data);
 199 #endif
 200                                         if (!strcmp(arg, l->data)) {
 201                                                 llist_unlink(&aborts, l);
 202                                                 continue;
 203                                         }
 204 #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 205                                         if (len > max_abort_len)
 206                                                 max_abort_len = len;
 207 #endif
 208                                 }
 209 #endif
 210                         } else if (DIR_TIMEOUT == key) {
 211                                 // set new timeout
 212                                 // -1 means OFF
 213                                 timeout = atoi(arg) * 1000;
 214                                 // 0 means default
 215                                 // >0 means value in msecs
 216                                 if (!timeout)
 217                                         timeout = DEFAULT_CHAT_TIMEOUT;
 218                         } else if (DIR_ECHO == key) {
 219                                 // turn echo on/off
 220                                 // N.B. echo means dumping output
 221                                 // from stdin (device) to stderr
 222                                 echo = onoff;
 223 //TODO?                         echo_fd = onoff * STDERR_FILENO;
 224 //TODO?                         echo_fd = xopen(arg, O_WRONLY|O_CREAT|O_TRUNC);
 225                         } else if (DIR_SAY == key) {
 226                                 // just print argument verbatim
 227                                 fprintf(stderr, arg);
 228                         }
 229                         // next, please!
 230                         argv++;
 231                 // ordinary expect-send pair!
 232                 } else {
 233                         //-----------------------
 234                         // do expect
 235                         //-----------------------
 236                         int expect_len;
 237                         size_t buf_len = 0;
 238                         size_t max_len = max_abort_len;
 239
 240                         struct pollfd pfd;
 241 #if ENABLE_FEATURE_CHAT_NOFAIL
 242                         int nofail = 0;
 243 #endif
 244                         char *expect = *argv++;
 245
 246                         // sanity check: shall we really expect something?
 247                         if (!expect)
 248                                 goto expect_done;
 249
 250 #if ENABLE_FEATURE_CHAT_NOFAIL
 251                         // if expect starts with -
 252                         if ('-' == *expect) {
 253                                 // swallow -
 254                                 expect++;
 255                                 // and enter nofail mode
 256                                 nofail++;
 257                         }
 258 #endif
 259
 260 #ifdef ___TEST___BUF___ // test behaviour with a small buffer
 261 #       undef COMMON_BUFSIZE
 262 #       define COMMON_BUFSIZE 6
 263 #endif
 264                         // expand escape sequences in expect
 265                         expect_len = unescape(expect, &expect_len /*dummy*/);
 266                         if (expect_len > max_len)
 267                                 max_len = expect_len;
 268                         // sanity check:
 269                         // we should expect more than nothing but not more than input buffer
 270                         // TODO: later we'll get rid of fixed-size buffer
 271                         if (!expect_len)
 272                                 goto expect_done;
 273                         if (max_len >= COMMON_BUFSIZE) {
 274                                 exitcode = ERR_MEM;
 275                                 goto expect_done;
 276                         }
 277
 278                         // get reply
 279                         pfd.fd = STDIN_FILENO;
 280                         pfd.events = POLLIN;
 281                         while (!exitcode
 282                             && poll(&pfd, 1, timeout) > 0
 283                             && (pfd.revents & POLLIN)
 284                         ) {
 285 #define buf bb_common_bufsiz1
 286                                 llist_t *l;
 287                                 ssize_t delta;
 288
 289                                 // read next char from device
 290                                 if (safe_read(STDIN_FILENO, buf+buf_len, 1) > 0) {
 291                                         // dump device output if ECHO ON or RECORD fname
 292 //TODO?                                 if (echo_fd > 0) {
 293 //TODO?                                         full_write(echo_fd, buf+buf_len, 1);
 294 //TODO?                                 }
 295                                         if (echo > 0)
 296                                                 full_write(STDERR_FILENO, buf+buf_len, 1);
 297                                         buf_len++;
 298                                         // move input frame if we've reached higher bound
 299                                         if (buf_len > COMMON_BUFSIZE) {
 300                                                 memmove(buf, buf+buf_len-max_len, max_len);
 301                                                 buf_len = max_len;
 302                                         }
 303                                 }
 304                                 // N.B. rule of thumb: values being looked for can
 305                                 // be found only at the end of input buffer
 306                                 // this allows to get rid of strstr() and memmem()
 307
 308                                 // TODO: make expect and abort strings processed uniformly
 309                                 // abort condition is met? -> bail out
 310                                 for (l = aborts, exitcode = ERR_ABORT; l; l = l->link, ++exitcode) {
 311                                         size_t len = strlen(l->data);
 312                                         delta = buf_len-len;
 313                                         if (delta >= 0 && !memcmp(buf+delta, l->data, len))
 314                                                 goto expect_done;
 315                                 }
 316                                 exitcode = ERR_OK;
 317
 318                                 // expected reply received? -> goto next command
 319                                 delta = buf_len - expect_len;
 320                                 if (delta >= 0 && !memcmp(buf+delta, expect, expect_len))
 321                                         goto expect_done;
 322 #undef buf
 323                         }
 324
 325                         // device timed out or unexpected reply received
 326                         exitcode = ERR_TIMEOUT;
 327  expect_done:
 328 #if ENABLE_FEATURE_CHAT_NOFAIL
 329                         // on success and when in nofail mode
 330                         // we should skip following subsend-subexpect pairs
 331                         if (nofail) {
 332                                 if (!exitcode) {
 333                                         // find last send before non-dashed expect
 334                                         while (*argv && argv[1] && '-' == argv[1][0])
 335                                                 argv += 2;
 336                                         // skip the pair
 337                                         // N.B. do we really need this?!
 338                                         if (!*argv++ || !*argv++)
 339                                                 break;
 340                                 }
 341                                 // nofail mode also clears all but IO errors (or signals)
 342                                 if (ERR_IO != exitcode)
 343                                         exitcode = ERR_OK;
 344                         }
 345 #endif
 346                         // bail out unless we expected successfully
 347                         if (exitcode)
 348                                 break;
 349
 350                         //-----------------------
 351                         // do send
 352                         //-----------------------
 353                         if (*argv) {
 354 #if ENABLE_FEATURE_CHAT_IMPLICIT_CR
 355                                 int nocr = 0; // inhibit terminating command with \r
 356 #endif
 357                                 char *loaded = NULL; // loaded command
 358                                 size_t len;
 359                                 char *buf = *argv++;
 360
 361                                 // if command starts with @
 362                                 // load "real" command from file named after @
 363                                 if ('@' == *buf) {
 364                                         // skip the @ and any following white-space
 365                                         trim(++buf);
 366                                         buf = loaded = xmalloc_xopen_read_close(buf, NULL);
 367                                 }
 368
 369                                 // expand escape sequences in command
 370                                 len = unescape(buf, &nocr);
 371
 372                                 // send command
 373 #if ENABLE_FEATURE_CHAT_SEND_ESCAPES
 374                                 pfd.fd = STDOUT_FILENO;
 375                                 pfd.events = POLLOUT;
 376                                 while (len && !exitcode
 377                                     && poll(&pfd, 1, timeout) > 0
 378                                     && (pfd.revents & POLLOUT)
 379                                 ) {
 380                                         // ugly! ugly! ugly!
 381                                         // gotta send char by char to achieve this!
 382                                         // Brrr...
 383                                         // "\\d" means 1 sec delay, "\\p" means 0.01 sec delay
 384                                         // "\\K" means send BREAK
 385                                         char c = *buf;
 386                                         if ('\\' == c) {
 387                                                 c = *++buf;
 388                                                 if ('d' == c) {
 389                                                         sleep(1);
 390                                                         len--;
 391                                                         continue;
 392                                                 } else if ('p' == c) {
 393                                                         usleep(10000);
 394                                                         len--;
 395                                                         continue;
 396                                                 } else if ('K' == c) {
 397                                                         tcsendbreak(STDOUT_FILENO, 0);
 398                                                         len--;
 399                                                         continue;
 400                                                 } else {
 401                                                         buf--;
 402                                                 }
 403                                         }
 404                                         if (safe_write(STDOUT_FILENO, buf, 1) > 0) {
 405                                                 len--;
 406                                                 buf++;
 407                                         } else
 408                                                 break;
 409                                 }
 410 #else
 411 //                              if (len) {
 412                                         alarm(timeout);
 413                                         len -= full_write(STDOUT_FILENO, buf, len);
 414                                         alarm(0);
 415 //                              }
 416 #endif
 417
 418                                 // report I/O error if there still exists at least one non-sent char
 419                                 if (len)
 420                                         exitcode = ERR_IO;
 421
 422                                 // free loaded command (if any)
 423                                 if (loaded)
 424                                         free(loaded);
 425 #if ENABLE_FEATURE_CHAT_IMPLICIT_CR
 426                                 // or terminate command with \r (if not inhibited)
 427                                 else if (!nocr)
 428                                         xwrite(STDOUT_FILENO, "\r", 1);
 429 #endif
 430
 431                                 // bail out unless we sent command successfully
 432                                 if (exitcode)
 433                                         break;
 434
 435                         }
 436                 }
 437         }
 438
 439 #if ENABLE_FEATURE_CHAT_TTY_HIFI
 440         tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
 441 #endif
 442
 443         return exitcode;
 444 }