token.c

   1 /*
   2  * Routines used by the file-transfer code.
   3  *
   4  * Copyright (C) 1996 Andrew Tridgell
   5  * Copyright (C) 1996 Paul Mackerras
   6  * Copyright (C) 2003-2020 Wayne Davison
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, visit the http://fsf.org website.
  20  */
  21
  22 #include "rsync.h"
  23 #include "itypes.h"
  24 #include <zlib.h>
  25
  26 extern int do_compression;
  27 extern int protocol_version;
  28 extern int module_id;
  29 extern int do_compression_level;
  30 extern char *skip_compress;
  31
  32 #ifndef Z_INSERT_ONLY
  33 #define Z_INSERT_ONLY Z_SYNC_FLUSH
  34 #endif
  35
  36 static int compression_level, per_file_default_level;
  37
  38 struct suffix_tree {
  39         struct suffix_tree *sibling;
  40         struct suffix_tree *child;
  41         char letter, word_end;
  42 };
  43
  44 static char *match_list;
  45 static struct suffix_tree *suftree;
  46
  47 void init_compression_level(void)
  48 {
  49         int min_level, max_level, def_level, off_level;
  50
  51         switch (do_compression) {
  52         case CPRES_ZLIB:
  53         case CPRES_ZLIBX:
  54                 min_level = 1;
  55                 max_level = Z_BEST_COMPRESSION;
  56                 def_level = 6; /* Z_DEFAULT_COMPRESSION is -1, so set it to the real default */
  57                 off_level = Z_NO_COMPRESSION;
  58                 if (do_compression_level == Z_DEFAULT_COMPRESSION)
  59                         do_compression_level = def_level;
  60                 break;
  61         default: /* paranoia to prevent missing case values */
  62                 exit_cleanup(RERR_UNSUPPORTED);
  63         }
  64
  65         if (do_compression_level == off_level) {
  66                 do_compression = CPRES_NONE;
  67                 return;
  68         }
  69
  70         /* We don't bother with any errors or warnings -- just make sure that the values are valid. */
  71         if (do_compression_level == CLVL_NOT_SPECIFIED)
  72                 do_compression_level = def_level;
  73         else if (do_compression_level < min_level)
  74                 do_compression_level = min_level;
  75         else if (do_compression_level > max_level)
  76                 do_compression_level = max_level;
  77 }
  78
  79 static void add_suffix(struct suffix_tree **prior, char ltr, const char *str)
  80 {
  81         struct suffix_tree *node, *newnode;
  82
  83         if (ltr == '[') {
  84                 const char *after = strchr(str, ']');
  85                 /* Treat "[foo" and "[]" as having a literal '['. */
  86                 if (after && after++ != str+1) {
  87                         while ((ltr = *str++) != ']')
  88                                 add_suffix(prior, ltr, after);
  89                         return;
  90                 }
  91         }
  92
  93         for (node = *prior; node; prior = &node->sibling, node = node->sibling) {
  94                 if (node->letter == ltr) {
  95                         if (*str)
  96                                 add_suffix(&node->child, *str, str+1);
  97                         else
  98                                 node->word_end = 1;
  99                         return;
 100                 }
 101                 if (node->letter > ltr)
 102                         break;
 103         }
 104         if (!(newnode = new(struct suffix_tree)))
 105                 out_of_memory("add_suffix");
 106         newnode->sibling = node;
 107         newnode->child = NULL;
 108         newnode->letter = ltr;
 109         *prior = newnode;
 110         if (*str) {
 111                 add_suffix(&newnode->child, *str, str+1);
 112                 newnode->word_end = 0;
 113         } else
 114                 newnode->word_end = 1;
 115 }
 116
 117 static void add_nocompress_suffixes(const char *str)
 118 {
 119         char *buf, *t;
 120         const char *f = str;
 121
 122         if (!(buf = new_array(char, strlen(f) + 1)))
 123                 out_of_memory("add_nocompress_suffixes");
 124
 125         while (*f) {
 126                 if (*f == '/') {
 127                         f++;
 128                         continue;
 129                 }
 130
 131                 t = buf;
 132                 do {
 133                         if (isUpper(f))
 134                                 *t++ = toLower(f);
 135                         else
 136                                 *t++ = *f;
 137                 } while (*++f != '/' && *f);
 138                 *t++ = '\0';
 139
 140                 add_suffix(&suftree, *buf, buf+1);
 141         }
 142
 143         free(buf);
 144 }
 145
 146 static void init_set_compression(void)
 147 {
 148         const char *f;
 149         char *t, *start;
 150
 151         if (skip_compress)
 152                 add_nocompress_suffixes(skip_compress);
 153
 154         /* A non-daemon transfer skips the default suffix list if the
 155          * user specified --skip-compress. */
 156         if (skip_compress && module_id < 0)
 157                 f = "";
 158         else
 159                 f = lp_dont_compress(module_id);
 160
 161         if (!(match_list = t = new_array(char, strlen(f) + 2)))
 162                 out_of_memory("set_compression");
 163
 164         per_file_default_level = do_compression_level;
 165
 166         while (*f) {
 167                 if (*f == ' ') {
 168                         f++;
 169                         continue;
 170                 }
 171
 172                 start = t;
 173                 do {
 174                         if (isUpper(f))
 175                                 *t++ = toLower(f);
 176                         else
 177                                 *t++ = *f;
 178                 } while (*++f != ' ' && *f);
 179                 *t++ = '\0';
 180
 181                 if (t - start == 1+1 && *start == '*') {
 182                         /* Optimize a match-string of "*". */
 183                         *match_list = '\0';
 184                         suftree = NULL;
 185                         per_file_default_level = 0;
 186                         break;
 187                 }
 188
 189                 /* Move *.foo items into the stuffix tree. */
 190                 if (*start == '*' && start[1] == '.' && start[2]
 191                  && !strpbrk(start+2, ".?*")) {
 192                         add_suffix(&suftree, start[2], start+3);
 193                         t = start;
 194                 }
 195         }
 196         *t++ = '\0';
 197 }
 198
 199 /* determine the compression level based on a wildcard filename list */
 200 void set_compression(const char *fname)
 201 {
 202         const struct suffix_tree *node;
 203         const char *s;
 204         char ltr;
 205
 206         if (!do_compression)
 207                 return;
 208
 209         if (!match_list)
 210                 init_set_compression();
 211
 212         compression_level = per_file_default_level;
 213
 214         if (!*match_list && !suftree)
 215                 return;
 216
 217         if ((s = strrchr(fname, '/')) != NULL)
 218                 fname = s + 1;
 219
 220         for (s = match_list; *s; s += strlen(s) + 1) {
 221                 if (iwildmatch(s, fname)) {
 222                         compression_level = 0;
 223                         return;
 224                 }
 225         }
 226
 227         if (!(node = suftree) || !(s = strrchr(fname, '.'))
 228          || s == fname || !(ltr = *++s))
 229                 return;
 230
 231         while (1) {
 232                 if (isUpper(&ltr))
 233                         ltr = toLower(&ltr);
 234                 while (node->letter != ltr) {
 235                         if (node->letter > ltr)
 236                                 return;
 237                         if (!(node = node->sibling))
 238                                 return;
 239                 }
 240                 if ((ltr = *++s) == '\0') {
 241                         if (node->word_end)
 242                                 compression_level = 0;
 243                         return;
 244                 }
 245                 if (!(node = node->child))
 246                         return;
 247         }
 248 }
 249
 250 /* non-compressing recv token */
 251 static int32 simple_recv_token(int f, char **data)
 252 {
 253         static int32 residue;
 254         static char *buf;
 255         int32 n;
 256
 257         if (!buf) {
 258                 buf = new_array(char, CHUNK_SIZE);
 259                 if (!buf)
 260                         out_of_memory("simple_recv_token");
 261         }
 262
 263         if (residue == 0) {
 264                 int32 i = read_int(f);
 265                 if (i <= 0)
 266                         return i;
 267                 residue = i;
 268         }
 269
 270         *data = buf;
 271         n = MIN(CHUNK_SIZE,residue);
 272         residue -= n;
 273         read_buf(f,buf,n);
 274         return n;
 275 }
 276
 277 /* non-compressing send token */
 278 static void simple_send_token(int f, int32 token, struct map_struct *buf,
 279                               OFF_T offset, int32 n)
 280 {
 281         if (n > 0) {
 282                 int32 len = 0;
 283                 while (len < n) {
 284                         int32 n1 = MIN(CHUNK_SIZE, n-len);
 285                         write_int(f, n1);
 286                         write_buf(f, map_ptr(buf, offset+len, n1), n1);
 287                         len += n1;
 288                 }
 289         }
 290         /* a -2 token means to send data only and no token */
 291         if (token != -2)
 292                 write_int(f, -(token+1));
 293 }
 294
 295 /* Flag bytes in compressed stream are encoded as follows: */
 296 #define END_FLAG        0       /* that's all folks */
 297 #define TOKEN_LONG      0x20    /* followed by 32-bit token number */
 298 #define TOKENRUN_LONG   0x21    /* ditto with 16-bit run count */
 299 #define DEFLATED_DATA   0x40    /* + 6-bit high len, then low len byte */
 300 #define TOKEN_REL       0x80    /* + 6-bit relative token number */
 301 #define TOKENRUN_REL    0xc0    /* ditto with 16-bit run count */
 302
 303 #define MAX_DATA_COUNT  16383   /* fit 14 bit count into 2 bytes with flags */
 304
 305 /* zlib.h says that if we want to be able to compress something in a single
 306  * call, avail_out must be at least 0.1% larger than avail_in plus 12 bytes.
 307  * We'll add in 0.1%+16, just to be safe (and we'll avoid floating point,
 308  * to ensure that this is a compile-time value). */
 309 #define AVAIL_OUT_SIZE(avail_in_size) ((avail_in_size)*1001/1000+16)
 310
 311 /* For coding runs of tokens */
 312 static int32 last_token = -1;
 313 static int32 run_start;
 314 static int32 last_run_end;
 315
 316 /* Deflation state */
 317 static z_stream tx_strm;
 318
 319 /* Output buffer */
 320 static char *obuf;
 321
 322 /* We want obuf to be able to hold both MAX_DATA_COUNT+2 bytes as well as
 323  * AVAIL_OUT_SIZE(CHUNK_SIZE) bytes, so make sure that it's large enough. */
 324 #if MAX_DATA_COUNT+2 > AVAIL_OUT_SIZE(CHUNK_SIZE)
 325 #define OBUF_SIZE       (MAX_DATA_COUNT+2)
 326 #else
 327 #define OBUF_SIZE       AVAIL_OUT_SIZE(CHUNK_SIZE)
 328 #endif
 329
 330 /* Send a deflated token */
 331 static void
 332 send_deflated_token(int f, int32 token, struct map_struct *buf, OFF_T offset,
 333                     int32 nb, int32 toklen)
 334 {
 335         static int init_done, flush_pending;
 336         int32 n, r;
 337
 338         if (last_token == -1) {
 339                 /* initialization */
 340                 if (!init_done) {
 341                         tx_strm.next_in = NULL;
 342                         tx_strm.zalloc = NULL;
 343                         tx_strm.zfree = NULL;
 344                         if (deflateInit2(&tx_strm, compression_level,
 345                                          Z_DEFLATED, -15, 8,
 346                                          Z_DEFAULT_STRATEGY) != Z_OK) {
 347                                 rprintf(FERROR, "compression init failed\n");
 348                                 exit_cleanup(RERR_PROTOCOL);
 349                         }
 350                         if ((obuf = new_array(char, OBUF_SIZE)) == NULL)
 351                                 out_of_memory("send_deflated_token");
 352                         init_done = 1;
 353                 } else
 354                         deflateReset(&tx_strm);
 355                 last_run_end = 0;
 356                 run_start = token;
 357                 flush_pending = 0;
 358         } else if (last_token == -2) {
 359                 run_start = token;
 360         } else if (nb != 0 || token != last_token + 1
 361                    || token >= run_start + 65536) {
 362                 /* output previous run */
 363                 r = run_start - last_run_end;
 364                 n = last_token - run_start;
 365                 if (r >= 0 && r <= 63) {
 366                         write_byte(f, (n==0? TOKEN_REL: TOKENRUN_REL) + r);
 367                 } else {
 368                         write_byte(f, (n==0? TOKEN_LONG: TOKENRUN_LONG));
 369                         write_int(f, run_start);
 370                 }
 371                 if (n != 0) {
 372                         write_byte(f, n);
 373                         write_byte(f, n >> 8);
 374                 }
 375                 last_run_end = last_token;
 376                 run_start = token;
 377         }
 378
 379         last_token = token;
 380
 381         if (nb != 0 || flush_pending) {
 382                 /* deflate the data starting at offset */
 383                 int flush = Z_NO_FLUSH;
 384                 tx_strm.avail_in = 0;
 385                 tx_strm.avail_out = 0;
 386                 do {
 387                         if (tx_strm.avail_in == 0 && nb != 0) {
 388                                 /* give it some more input */
 389                                 n = MIN(nb, CHUNK_SIZE);
 390                                 tx_strm.next_in = (Bytef *)
 391                                         map_ptr(buf, offset, n);
 392                                 tx_strm.avail_in = n;
 393                                 nb -= n;
 394                                 offset += n;
 395                         }
 396                         if (tx_strm.avail_out == 0) {
 397                                 tx_strm.next_out = (Bytef *)(obuf + 2);
 398                                 tx_strm.avail_out = MAX_DATA_COUNT;
 399                                 if (flush != Z_NO_FLUSH) {
 400                                         /*
 401                                          * We left the last 4 bytes in the
 402                                          * buffer, in case they are the
 403                                          * last 4.  Move them to the front.
 404                                          */
 405                                         memcpy(tx_strm.next_out,
 406                                                obuf+MAX_DATA_COUNT-2, 4);
 407                                         tx_strm.next_out += 4;
 408                                         tx_strm.avail_out -= 4;
 409                                 }
 410                         }
 411                         if (nb == 0 && token != -2)
 412                                 flush = Z_SYNC_FLUSH;
 413                         r = deflate(&tx_strm, flush);
 414                         if (r != Z_OK) {
 415                                 rprintf(FERROR, "deflate returned %d\n", r);
 416                                 exit_cleanup(RERR_STREAMIO);
 417                         }
 418                         if (nb == 0 || tx_strm.avail_out == 0) {
 419                                 n = MAX_DATA_COUNT - tx_strm.avail_out;
 420                                 if (flush != Z_NO_FLUSH) {
 421                                         /*
 422                                          * We have to trim off the last 4
 423                                          * bytes of output when flushing
 424                                          * (they are just 0, 0, ff, ff).
 425                                          */
 426                                         n -= 4;
 427                                 }
 428                                 if (n > 0) {
 429                                         obuf[0] = DEFLATED_DATA + (n >> 8);
 430                                         obuf[1] = n;
 431                                         write_buf(f, obuf, n+2);
 432                                 }
 433                         }
 434                 } while (nb != 0 || tx_strm.avail_out == 0);
 435                 flush_pending = token == -2;
 436         }
 437
 438         if (token == -1) {
 439                 /* end of file - clean up */
 440                 write_byte(f, END_FLAG);
 441         } else if (token != -2 && do_compression == CPRES_ZLIB) {
 442                 /* Add the data in the current block to the compressor's
 443                  * history and hash table. */
 444                 do {
 445                         /* Break up long sections in the same way that
 446                          * see_deflate_token() does. */
 447                         int32 n1 = toklen > 0xffff ? 0xffff : toklen;
 448                         toklen -= n1;
 449                         tx_strm.next_in = (Bytef *)map_ptr(buf, offset, n1);
 450                         tx_strm.avail_in = n1;
 451                         if (protocol_version >= 31) /* Newer protocols avoid a data-duplicating bug */
 452                                 offset += n1;
 453                         tx_strm.next_out = (Bytef *) obuf;
 454                         tx_strm.avail_out = AVAIL_OUT_SIZE(CHUNK_SIZE);
 455                         r = deflate(&tx_strm, Z_INSERT_ONLY);
 456                         if (r != Z_OK || tx_strm.avail_in != 0) {
 457                                 rprintf(FERROR, "deflate on token returned %d (%d bytes left)\n",
 458                                         r, tx_strm.avail_in);
 459                                 exit_cleanup(RERR_STREAMIO);
 460                         }
 461                 } while (toklen > 0);
 462         }
 463 }
 464
 465 /* tells us what the receiver is in the middle of doing */
 466 static enum { r_init, r_idle, r_running, r_inflating, r_inflated } recv_state;
 467
 468 /* for inflating stuff */
 469 static z_stream rx_strm;
 470 static char *cbuf;
 471 static char *dbuf;
 472
 473 /* for decoding runs of tokens */
 474 static int32 rx_token;
 475 static int32 rx_run;
 476
 477 /* Receive a deflated token and inflate it */
 478 static int32 recv_deflated_token(int f, char **data)
 479 {
 480         static int init_done;
 481         static int32 saved_flag;
 482         int32 n, flag;
 483         int r;
 484
 485         for (;;) {
 486                 switch (recv_state) {
 487                 case r_init:
 488                         if (!init_done) {
 489                                 rx_strm.next_out = NULL;
 490                                 rx_strm.zalloc = NULL;
 491                                 rx_strm.zfree = NULL;
 492                                 if (inflateInit2(&rx_strm, -15) != Z_OK) {
 493                                         rprintf(FERROR, "inflate init failed\n");
 494                                         exit_cleanup(RERR_PROTOCOL);
 495                                 }
 496                                 if (!(cbuf = new_array(char, MAX_DATA_COUNT))
 497                                     || !(dbuf = new_array(char, AVAIL_OUT_SIZE(CHUNK_SIZE))))
 498                                         out_of_memory("recv_deflated_token");
 499                                 init_done = 1;
 500                         } else {
 501                                 inflateReset(&rx_strm);
 502                         }
 503                         recv_state = r_idle;
 504                         rx_token = 0;
 505                         break;
 506
 507                 case r_idle:
 508                 case r_inflated:
 509                         if (saved_flag) {
 510                                 flag = saved_flag & 0xff;
 511                                 saved_flag = 0;
 512                         } else
 513                                 flag = read_byte(f);
 514                         if ((flag & 0xC0) == DEFLATED_DATA) {
 515                                 n = ((flag & 0x3f) << 8) + read_byte(f);
 516                                 read_buf(f, cbuf, n);
 517                                 rx_strm.next_in = (Bytef *)cbuf;
 518                                 rx_strm.avail_in = n;
 519                                 recv_state = r_inflating;
 520                                 break;
 521                         }
 522                         if (recv_state == r_inflated) {
 523                                 /* check previous inflated stuff ended correctly */
 524                                 rx_strm.avail_in = 0;
 525                                 rx_strm.next_out = (Bytef *)dbuf;
 526                                 rx_strm.avail_out = AVAIL_OUT_SIZE(CHUNK_SIZE);
 527                                 r = inflate(&rx_strm, Z_SYNC_FLUSH);
 528                                 n = AVAIL_OUT_SIZE(CHUNK_SIZE) - rx_strm.avail_out;
 529                                 /*
 530                                  * Z_BUF_ERROR just means no progress was
 531                                  * made, i.e. the decompressor didn't have
 532                                  * any pending output for us.
 533                                  */
 534                                 if (r != Z_OK && r != Z_BUF_ERROR) {
 535                                         rprintf(FERROR, "inflate flush returned %d (%d bytes)\n",
 536                                                 r, n);
 537                                         exit_cleanup(RERR_STREAMIO);
 538                                 }
 539                                 if (n != 0 && r != Z_BUF_ERROR) {
 540                                         /* have to return some more data and
 541                                            save the flag for later. */
 542                                         saved_flag = flag + 0x10000;
 543                                         *data = dbuf;
 544                                         return n;
 545                                 }
 546                                 /*
 547                                  * At this point the decompressor should
 548                                  * be expecting to see the 0, 0, ff, ff bytes.
 549                                  */
 550                                 if (!inflateSyncPoint(&rx_strm)) {
 551                                         rprintf(FERROR, "decompressor lost sync!\n");
 552                                         exit_cleanup(RERR_STREAMIO);
 553                                 }
 554                                 rx_strm.avail_in = 4;
 555                                 rx_strm.next_in = (Bytef *)cbuf;
 556                                 cbuf[0] = cbuf[1] = 0;
 557                                 cbuf[2] = cbuf[3] = 0xff;
 558                                 inflate(&rx_strm, Z_SYNC_FLUSH);
 559                                 recv_state = r_idle;
 560                         }
 561                         if (flag == END_FLAG) {
 562                                 /* that's all folks */
 563                                 recv_state = r_init;
 564                                 return 0;
 565                         }
 566
 567                         /* here we have a token of some kind */
 568                         if (flag & TOKEN_REL) {
 569                                 rx_token += flag & 0x3f;
 570                                 flag >>= 6;
 571                         } else
 572                                 rx_token = read_int(f);
 573                         if (flag & 1) {
 574                                 rx_run = read_byte(f);
 575                                 rx_run += read_byte(f) << 8;
 576                                 recv_state = r_running;
 577                         }
 578                         return -1 - rx_token;
 579
 580                 case r_inflating:
 581                         rx_strm.next_out = (Bytef *)dbuf;
 582                         rx_strm.avail_out = AVAIL_OUT_SIZE(CHUNK_SIZE);
 583                         r = inflate(&rx_strm, Z_NO_FLUSH);
 584                         n = AVAIL_OUT_SIZE(CHUNK_SIZE) - rx_strm.avail_out;
 585                         if (r != Z_OK) {
 586                                 rprintf(FERROR, "inflate returned %d (%d bytes)\n", r, n);
 587                                 exit_cleanup(RERR_STREAMIO);
 588                         }
 589                         if (rx_strm.avail_in == 0)
 590                                 recv_state = r_inflated;
 591                         if (n != 0) {
 592                                 *data = dbuf;
 593                                 return n;
 594                         }
 595                         break;
 596
 597                 case r_running:
 598                         ++rx_token;
 599                         if (--rx_run == 0)
 600                                 recv_state = r_idle;
 601                         return -1 - rx_token;
 602                 }
 603         }
 604 }
 605
 606 /*
 607  * put the data corresponding to a token that we've just returned
 608  * from recv_deflated_token into the decompressor's history buffer.
 609  */
 610 static void see_deflate_token(char *buf, int32 len)
 611 {
 612         int r;
 613         int32 blklen;
 614         unsigned char hdr[5];
 615
 616         rx_strm.avail_in = 0;
 617         blklen = 0;
 618         hdr[0] = 0;
 619         do {
 620                 if (rx_strm.avail_in == 0 && len != 0) {
 621                         if (blklen == 0) {
 622                                 /* Give it a fake stored-block header. */
 623                                 rx_strm.next_in = (Bytef *)hdr;
 624                                 rx_strm.avail_in = 5;
 625                                 blklen = len;
 626                                 if (blklen > 0xffff)
 627                                         blklen = 0xffff;
 628                                 hdr[1] = blklen;
 629                                 hdr[2] = blklen >> 8;
 630                                 hdr[3] = ~hdr[1];
 631                                 hdr[4] = ~hdr[2];
 632                         } else {
 633                                 rx_strm.next_in = (Bytef *)buf;
 634                                 rx_strm.avail_in = blklen;
 635                                 if (protocol_version >= 31) /* Newer protocols avoid a data-duplicating bug */
 636                                         buf += blklen;
 637                                 len -= blklen;
 638                                 blklen = 0;
 639                         }
 640                 }
 641                 rx_strm.next_out = (Bytef *)dbuf;
 642                 rx_strm.avail_out = AVAIL_OUT_SIZE(CHUNK_SIZE);
 643                 r = inflate(&rx_strm, Z_SYNC_FLUSH);
 644                 if (r != Z_OK && r != Z_BUF_ERROR) {
 645                         rprintf(FERROR, "inflate (token) returned %d\n", r);
 646                         exit_cleanup(RERR_STREAMIO);
 647                 }
 648         } while (len || rx_strm.avail_out == 0);
 649 }
 650
 651 /**
 652  * Transmit a verbatim buffer of length @p n followed by a token.
 653  * If token == -1 then we have reached EOF
 654  * If n == 0 then don't send a buffer
 655  */
 656 void send_token(int f, int32 token, struct map_struct *buf, OFF_T offset,
 657                 int32 n, int32 toklen)
 658 {
 659         if (!do_compression)
 660                 simple_send_token(f, token, buf, offset, n);
 661         else
 662                 send_deflated_token(f, token, buf, offset, n, toklen);
 663 }
 664
 665 /*
 666  * receive a token or buffer from the other end. If the return value is >0 then
 667  * it is a data buffer of that length, and *data will point at the data.
 668  * if the return value is -i then it represents token i-1
 669  * if the return value is 0 then the end has been reached
 670  */
 671 int32 recv_token(int f, char **data)
 672 {
 673         int tok;
 674
 675         if (!do_compression)
 676                 tok = simple_recv_token(f,data);
 677         else /* CPRES_ZLIB & CPRES_ZLIBX */
 678                 tok = recv_deflated_token(f, data);
 679         return tok;
 680 }
 681
 682 /*
 683  * look at the data corresponding to a token, if necessary
 684  */
 685 void see_token(char *data, int32 toklen)
 686 {
 687         if (do_compression == CPRES_ZLIB)
 688                 see_deflate_token(data, toklen);
 689 }