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 source tree.
   9  */
  10 #include "libbb.h"
  11
  12 // default timeout: 45 sec
  13 #define DEFAULT_CHAT_TIMEOUT 45*1000
  14 // max length of "abort string",
  15 // i.e. device reply which causes termination
  16 #define MAX_ABORT_LEN 50
  17
  18 // possible exit codes
  19 enum {
  20         ERR_OK = 0,     // all's well
  21         ERR_MEM,        // read too much while expecting
  22         ERR_IO,         // signalled or I/O error
  23         ERR_TIMEOUT,    // timed out while expecting
  24         ERR_ABORT,      // first abort condition was met
  25 //      ERR_ABORT2,     // second abort condition was met
  26 //      ...
  27 };
  28
  29 // exit code
  30 #define exitcode bb_got_signal
  31
  32 // trap for critical signals
  33 static void signal_handler(UNUSED_PARAM int signo)
  34 {
  35         // report I/O error condition
  36         exitcode = ERR_IO;
  37 }
  38
  39 #if !ENABLE_FEATURE_CHAT_IMPLICIT_CR
  40 #define unescape(s, nocr) unescape(s)
  41 #endif
  42 static size_t unescape(char *s, int *nocr)
  43 {
  44         char *start = s;
  45         char *p = s;
  46
  47         while (*s) {
  48                 char c = *s;
  49                 // do we need special processing?
  50                 // standard escapes + \s for space and \N for \0
  51                 // \c inhibits terminating \r for commands and is noop for expects
  52                 if ('\\' == c) {
  53                         c = *++s;
  54                         if (c) {
  55 #if ENABLE_FEATURE_CHAT_IMPLICIT_CR
  56                                 if ('c' == c) {
  57                                         *nocr = 1;
  58                                         goto next;
  59                                 }
  60 #endif
  61                                 if ('N' == c) {
  62                                         c = '\0';
  63                                 } else if ('s' == c) {
  64                                         c = ' ';
  65 #if ENABLE_FEATURE_CHAT_NOFAIL
  66                                 // unescape leading dash only
  67                                 // TODO: and only for expect, not command string
  68                                 } else if ('-' == c && (start + 1 == s)) {
  69                                         //c = '-';
  70 #endif
  71                                 } else {
  72                                         c = bb_process_escape_sequence((const char **)&s);
  73                                         s--;
  74                                 }
  75                         }
  76                 // ^A becomes \001, ^B -- \002 and so on...
  77                 } else if ('^' == c) {
  78                         c = *++s-'@';
  79                 }
  80                 // put unescaped char
  81                 *p++ = c;
  82 #if ENABLE_FEATURE_CHAT_IMPLICIT_CR
  83  next:
  84 #endif
  85                 // next char
  86                 s++;
  87         }
  88         *p = '\0';
  89
  90         return p - start;
  91 }
  92
  93 int chat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  94 int chat_main(int argc UNUSED_PARAM, char **argv)
  95 {
  96         int record_fd = -1;
  97         bool echo = 0;
  98         // collection of device replies which cause unconditional termination
  99         llist_t *aborts = NULL;
 100         // inactivity period
 101         int timeout = DEFAULT_CHAT_TIMEOUT;
 102         // maximum length of abort string
 103 #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 104         size_t max_abort_len = 0;
 105 #else
 106 #define max_abort_len MAX_ABORT_LEN
 107 #endif
 108 #if ENABLE_FEATURE_CHAT_TTY_HIFI
 109         struct termios tio0, tio;
 110 #endif
 111         // directive names
 112         enum {
 113                 DIR_HANGUP = 0,
 114                 DIR_ABORT,
 115 #if ENABLE_FEATURE_CHAT_CLR_ABORT
 116                 DIR_CLR_ABORT,
 117 #endif
 118                 DIR_TIMEOUT,
 119                 DIR_ECHO,
 120                 DIR_SAY,
 121                 DIR_RECORD,
 122         };
 123
 124         // make x* functions fail with correct exitcode
 125         xfunc_error_retval = ERR_IO;
 126
 127         // trap vanilla signals to prevent process from being killed suddenly
 128         bb_signals(0
 129                 + (1 << SIGHUP)
 130                 + (1 << SIGINT)
 131                 + (1 << SIGTERM)
 132                 + (1 << SIGPIPE)
 133                 , signal_handler);
 134
 135 #if ENABLE_FEATURE_CHAT_TTY_HIFI
 136         tcgetattr(STDIN_FILENO, &tio);
 137         tio0 = tio;
 138         cfmakeraw(&tio);
 139         tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio);
 140 #endif
 141
 142 #if ENABLE_FEATURE_CHAT_SWALLOW_OPTS
 143         getopt32(argv, "vVsSE");
 144         argv += optind;
 145 #else
 146         argv++; // goto first arg
 147 #endif
 148         // handle chat expect-send pairs
 149         while (*argv) {
 150                 // directive given? process it
 151                 int key = index_in_strings(
 152                         "HANGUP\0" "ABORT\0"
 153 #if ENABLE_FEATURE_CHAT_CLR_ABORT
 154                         "CLR_ABORT\0"
 155 #endif
 156                         "TIMEOUT\0" "ECHO\0" "SAY\0" "RECORD\0"
 157                         , *argv
 158                 );
 159                 if (key >= 0) {
 160                         // cache directive value
 161                         char *arg = *++argv;
 162                         // OFF -> 0, anything else -> 1
 163                         bool onoff = (0 != strcmp("OFF", arg));
 164                         // process directive
 165                         if (DIR_HANGUP == key) {
 166                                 // turn SIGHUP on/off
 167                                 signal(SIGHUP, onoff ? signal_handler : SIG_IGN);
 168                         } else if (DIR_ABORT == key) {
 169                                 // append the string to abort conditions
 170 #if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 171                                 size_t len = strlen(arg);
 172                                 if (len > max_abort_len)
 173                                         max_abort_len = len;
 174 #endif
 175                                 llist_add_to_end(&aborts, arg);
 176 #if ENABLE_FEATURE_CHAT_CLR_ABORT
 177                         } else if (DIR_CLR_ABORT == key) {
 178                                 llist_t *l;
 179                                 // remove the string from abort conditions
 180                                 // N.B. gotta refresh maximum length too...
 181 # if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 182                                 max_abort_len = 0;
 183 # endif
 184                                 for (l = aborts; l; l = l->link) {
 185 # if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 186                                         size_t len = strlen(l->data);
 187 # endif
 188                                         if (strcmp(arg, l->data) == 0) {
 189                                                 llist_unlink(&aborts, l);
 190                                                 continue;
 191                                         }
 192 # if ENABLE_FEATURE_CHAT_VAR_ABORT_LEN
 193                                         if (len > max_abort_len)
 194                                                 max_abort_len = len;
 195 # endif
 196                                 }
 197 #endif
 198                         } else if (DIR_TIMEOUT == key) {
 199                                 // set new timeout
 200                                 // -1 means OFF
 201                                 timeout = atoi(arg) * 1000;
 202                                 // 0 means default
 203                                 // >0 means value in msecs
 204                                 if (!timeout)
 205                                         timeout = DEFAULT_CHAT_TIMEOUT;
 206                         } else if (DIR_ECHO == key) {
 207                                 // turn echo on/off
 208                                 // N.B. echo means dumping device input/output to stderr
 209                                 echo = onoff;
 210                         } else if (DIR_RECORD == key) {
 211                                 // turn record on/off
 212                                 // N.B. record means dumping device input to a file
 213                                         // close previous record_fd
 214                                 if (record_fd > 0)
 215                                         close(record_fd);
 216                                 // N.B. do we have to die here on open error?
 217                                 record_fd = (onoff) ? xopen(arg, O_WRONLY|O_CREAT|O_TRUNC) : -1;
 218                         } else if (DIR_SAY == key) {
 219                                 // just print argument verbatim
 220                                 // TODO: should we use full_write() to avoid unistd/stdio conflict?
 221                                 bb_error_msg("%s", arg);
 222                         }
 223                         // next, please!
 224                         argv++;
 225                 // ordinary expect-send pair!
 226                 } else {
 227                         //-----------------------
 228                         // do expect
 229                         //-----------------------
 230                         int expect_len;
 231                         size_t buf_len = 0;
 232                         size_t max_len = max_abort_len;
 233
 234                         struct pollfd pfd;
 235 #if ENABLE_FEATURE_CHAT_NOFAIL
 236                         int nofail = 0;
 237 #endif
 238                         char *expect = *argv++;
 239
 240                         // sanity check: shall we really expect something?
 241                         if (!expect)
 242                                 goto expect_done;
 243
 244 #if ENABLE_FEATURE_CHAT_NOFAIL
 245                         // if expect starts with -
 246                         if ('-' == *expect) {
 247                                 // swallow -
 248                                 expect++;
 249                                 // and enter nofail mode
 250                                 nofail++;
 251                         }
 252 #endif
 253
 254 #ifdef ___TEST___BUF___ // test behaviour with a small buffer
 255 #       undef COMMON_BUFSIZE
 256 #       define COMMON_BUFSIZE 6
 257 #endif
 258                         // expand escape sequences in expect
 259                         expect_len = unescape(expect, &expect_len /*dummy*/);
 260                         if (expect_len > max_len)
 261                                 max_len = expect_len;
 262                         // sanity check:
 263                         // we should expect more than nothing but not more than input buffer
 264                         // TODO: later we'll get rid of fixed-size buffer
 265                         if (!expect_len)
 266                                 goto expect_done;
 267                         if (max_len >= COMMON_BUFSIZE) {
 268                                 exitcode = ERR_MEM;
 269                                 goto expect_done;
 270                         }
 271
 272                         // get reply
 273                         pfd.fd = STDIN_FILENO;
 274                         pfd.events = POLLIN;
 275                         while (!exitcode
 276                             && poll(&pfd, 1, timeout) > 0
 277                             && (pfd.revents & POLLIN)
 278                         ) {
 279 #define buf bb_common_bufsiz1
 280                                 llist_t *l;
 281                                 ssize_t delta;
 282
 283                                 // read next char from device
 284                                 if (safe_read(STDIN_FILENO, buf+buf_len, 1) > 0) {
 285                                         // dump device input if RECORD fname
 286                                         if (record_fd > 0) {
 287                                                 full_write(record_fd, buf+buf_len, 1);
 288                                         }
 289                                         // dump device input if ECHO ON
 290                                         if (echo > 0) {
 291 //                                              if (buf[buf_len] < ' ') {
 292 //                                                      full_write(STDERR_FILENO, "^", 1);
 293 //                                                      buf[buf_len] += '@';
 294 //                                              }
 295                                                 full_write(STDERR_FILENO, buf+buf_len, 1);
 296                                         }
 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                         } /* while (have data) */
 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                                 // expand escape sequences in command
 369                                 len = unescape(buf, &nocr);
 370
 371                                 // send command
 372                                 alarm(timeout);
 373                                 pfd.fd = STDOUT_FILENO;
 374                                 pfd.events = POLLOUT;
 375                                 while (len && !exitcode
 376                                     && poll(&pfd, 1, -1) > 0
 377                                     && (pfd.revents & POLLOUT)
 378                                 ) {
 379 #if ENABLE_FEATURE_CHAT_SEND_ESCAPES
 380                                         // "\\d" means 1 sec delay, "\\p" means 0.01 sec delay
 381                                         // "\\K" means send BREAK
 382                                         char c = *buf;
 383                                         if ('\\' == c) {
 384                                                 c = *++buf;
 385                                                 if ('d' == c) {
 386                                                         sleep(1);
 387                                                         len--;
 388                                                         continue;
 389                                                 }
 390                                                 if ('p' == c) {
 391                                                         usleep(10000);
 392                                                         len--;
 393                                                         continue;
 394                                                 }
 395                                                 if ('K' == c) {
 396                                                         tcsendbreak(STDOUT_FILENO, 0);
 397                                                         len--;
 398                                                         continue;
 399                                                 }
 400                                                 buf--;
 401                                         }
 402                                         if (safe_write(STDOUT_FILENO, buf, 1) != 1)
 403                                                 break;
 404                                         len--;
 405                                         buf++;
 406 #else
 407                                         len -= full_write(STDOUT_FILENO, buf, len);
 408 #endif
 409                                 } /* while (can write) */
 410                                 alarm(0);
 411
 412                                 // report I/O error if there still exists at least one non-sent char
 413                                 if (len)
 414                                         exitcode = ERR_IO;
 415
 416                                 // free loaded command (if any)
 417                                 if (loaded)
 418                                         free(loaded);
 419 #if ENABLE_FEATURE_CHAT_IMPLICIT_CR
 420                                 // or terminate command with \r (if not inhibited)
 421                                 else if (!nocr)
 422                                         xwrite(STDOUT_FILENO, "\r", 1);
 423 #endif
 424                                 // bail out unless we sent command successfully
 425                                 if (exitcode)
 426                                         break;
 427                         } /* if (*argv) */
 428                 }
 429         } /* while (*argv) */
 430
 431 #if ENABLE_FEATURE_CHAT_TTY_HIFI
 432         tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
 433 #endif
 434
 435         return exitcode;
 436 }