token.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1996
   3    Copyright (C) Paul Mackerras 1996
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #include "rsync.h"
  21 #include "zlib/zlib.h"
  22
  23 extern int do_compression;
  24
  25
  26 /* non-compressing recv token */
  27 static int simple_recv_token(int f,char **data)
  28 {
  29         static int residue;
  30         static char *buf;
  31         int n;
  32
  33         if (!buf) {
  34                 buf = (char *)malloc(CHUNK_SIZE);
  35                 if (!buf) out_of_memory("simple_recv_token");
  36         }
  37
  38         if (residue == 0) {
  39                 int i = read_int(f);
  40                 if (i <= 0) return i;
  41                 residue = i;
  42         }
  43
  44         *data = buf;
  45         n = MIN(CHUNK_SIZE,residue);
  46         residue -= n;
  47         read_buf(f,buf,n);
  48         return n;
  49 }
  50
  51
  52 /* non-compressing send token */
  53 static void simple_send_token(int f,int token,
  54                               struct map_struct *buf,OFF_T offset,int n)
  55 {
  56         if (n > 0) {
  57                 int l = 0;
  58                 while (l < n) {
  59                         int n1 = MIN(CHUNK_SIZE,n-l);
  60                         write_int(f,n1);
  61                         write_buf(f,map_ptr(buf,offset+l,n1),n1);
  62                         l += n1;
  63                 }
  64         }
  65         /* a -2 token means to send data only and no token */
  66         if (token != -2) {
  67                 write_int(f,-(token+1));
  68         }
  69 }
  70
  71
  72 /* Flag bytes in compressed stream are encoded as follows: */
  73 #define END_FLAG        0       /* that's all folks */
  74 #define TOKEN_LONG      0x20    /* followed by 32-bit token number */
  75 #define TOKENRUN_LONG   0x21    /* ditto with 16-bit run count */
  76 #define DEFLATED_DATA   0x40    /* + 6-bit high len, then low len byte */
  77 #define TOKEN_REL       0x80    /* + 6-bit relative token number */
  78 #define TOKENRUN_REL    0xc0    /* ditto with 16-bit run count */
  79
  80 #define MAX_DATA_COUNT  16383   /* fit 14 bit count into 2 bytes with flags */
  81
  82 /* For coding runs of tokens */
  83 static int last_token = -1;
  84 static int run_start;
  85 static int last_run_end;
  86
  87 /* Deflation state */
  88 static z_stream tx_strm;
  89
  90 /* Output buffer */
  91 static char *obuf;
  92
  93 /* Send a deflated token */
  94 static void
  95 send_deflated_token(int f, int token,
  96                     struct map_struct *buf, OFF_T offset, int nb, int toklen)
  97 {
  98         int n, r;
  99         static int init_done, flush_pending;
 100
 101         if (last_token == -1) {
 102                 /* initialization */
 103                 if (!init_done) {
 104                         tx_strm.next_in = NULL;
 105                         tx_strm.zalloc = NULL;
 106                         tx_strm.zfree = NULL;
 107                         if (deflateInit2(&tx_strm, Z_DEFAULT_COMPRESSION,
 108                                          Z_DEFLATED, -15, 8,
 109                                          Z_DEFAULT_STRATEGY) != Z_OK) {
 110                                 rprintf(FERROR, "compression init failed\n");
 111                                 exit_cleanup(1);
 112                         }
 113                         if ((obuf = malloc(MAX_DATA_COUNT+2)) == NULL)
 114                                 out_of_memory("send_deflated_token");
 115                         init_done = 1;
 116                 } else
 117                         deflateReset(&tx_strm);
 118                 last_run_end = 0;
 119                 run_start = token;
 120                 flush_pending = 0;
 121
 122         } else if (last_token == -2) {
 123                 run_start = token;
 124
 125         } else if (nb != 0 || token != last_token + 1
 126                    || token >= run_start + 65536) {
 127                 /* output previous run */
 128                 r = run_start - last_run_end;
 129                 n = last_token - run_start;
 130                 if (r >= 0 && r <= 63) {
 131                         write_byte(f, (n==0? TOKEN_REL: TOKENRUN_REL) + r);
 132                 } else {
 133                         write_byte(f, (n==0? TOKEN_LONG: TOKENRUN_LONG));
 134                         write_int(f, run_start);
 135                 }
 136                 if (n != 0) {
 137                         write_byte(f, n);
 138                         write_byte(f, n >> 8);
 139                 }
 140                 last_run_end = last_token;
 141                 run_start = token;
 142         }
 143
 144         last_token = token;
 145
 146         if (nb != 0 || flush_pending) {
 147                 /* deflate the data starting at offset */
 148                 int flush = Z_NO_FLUSH;
 149                 tx_strm.avail_in = 0;
 150                 tx_strm.avail_out = 0;
 151                 do {
 152                         if (tx_strm.avail_in == 0 && nb != 0) {
 153                                 /* give it some more input */
 154                                 n = MIN(nb, CHUNK_SIZE);
 155                                 tx_strm.next_in = (Bytef *)
 156                                         map_ptr(buf, offset, n);
 157                                 tx_strm.avail_in = n;
 158                                 nb -= n;
 159                                 offset += n;
 160                         }
 161                         if (tx_strm.avail_out == 0) {
 162                                 tx_strm.next_out = (Bytef *)(obuf + 2);
 163                                 tx_strm.avail_out = MAX_DATA_COUNT;
 164                                 if (flush != Z_NO_FLUSH) {
 165                                         /*
 166                                          * We left the last 4 bytes in the
 167                                          * buffer, in case they are the
 168                                          * last 4.  Move them to the front.
 169                                          */
 170                                         memcpy(tx_strm.next_out,
 171                                                obuf+MAX_DATA_COUNT-2, 4);
 172                                         tx_strm.next_out += 4;
 173                                         tx_strm.avail_out -= 4;
 174                                 }
 175                         }
 176                         if (nb == 0 && token != -2)
 177                                 flush = Z_SYNC_FLUSH;
 178                         r = deflate(&tx_strm, flush);
 179                         if (r != Z_OK) {
 180                                 rprintf(FERROR, "deflate returned %d\n", r);
 181                                 exit_cleanup(1);
 182                         }
 183                         if (nb == 0 || tx_strm.avail_out == 0) {
 184                                 n = MAX_DATA_COUNT - tx_strm.avail_out;
 185                                 if (flush != Z_NO_FLUSH) {
 186                                         /*
 187                                          * We have to trim off the last 4
 188                                          * bytes of output when flushing
 189                                          * (they are just 0, 0, ff, ff).
 190                                          */
 191                                         n -= 4;
 192                                 }
 193                                 if (n > 0) {
 194                                         obuf[0] = DEFLATED_DATA + (n >> 8);
 195                                         obuf[1] = n;
 196                                         write_buf(f, obuf, n+2);
 197                                 }
 198                         }
 199                 } while (nb != 0 || tx_strm.avail_out == 0);
 200                 flush_pending = token == -2;
 201         }
 202
 203         if (token == -1) {
 204                 /* end of file - clean up */
 205                 write_byte(f, END_FLAG);
 206
 207         } else if (token != -2) {
 208                 /* add the data in the current block to the compressor's
 209                    history and hash table */
 210                 tx_strm.next_in = (Bytef *) map_ptr(buf, offset, toklen);
 211                 tx_strm.avail_in = toklen;
 212                 tx_strm.next_out = (Bytef *) obuf;
 213                 tx_strm.avail_out = MAX_DATA_COUNT;
 214                 r = deflate(&tx_strm, Z_INSERT_ONLY);
 215                 if (r != Z_OK || tx_strm.avail_in != 0) {
 216                         rprintf(FERROR, "deflate on token returned %d (%d bytes left)\n",
 217                                 r, tx_strm.avail_in);
 218                         exit_cleanup(1);
 219                 }
 220         }
 221 }
 222
 223
 224 /* tells us what the receiver is in the middle of doing */
 225 static enum { r_init, r_idle, r_running, r_inflating, r_inflated } recv_state;
 226
 227 /* for inflating stuff */
 228 static z_stream rx_strm;
 229 static char *cbuf;
 230 static char *dbuf;
 231
 232 /* for decoding runs of tokens */
 233 static int rx_token;
 234 static int rx_run;
 235
 236 /* Receive a deflated token and inflate it */
 237 static int
 238 recv_deflated_token(int f, char **data)
 239 {
 240         int n, r, flag;
 241         static int init_done;
 242         static int saved_flag;
 243
 244         for (;;) {
 245                 switch (recv_state) {
 246                 case r_init:
 247                         if (!init_done) {
 248                                 rx_strm.next_out = NULL;
 249                                 rx_strm.zalloc = NULL;
 250                                 rx_strm.zfree = NULL;
 251                                 if (inflateInit2(&rx_strm, -15) != Z_OK) {
 252                                         rprintf(FERROR, "inflate init failed\n");
 253                                         exit_cleanup(1);
 254                                 }
 255                                 if ((cbuf = malloc(MAX_DATA_COUNT)) == NULL
 256                                     || (dbuf = malloc(CHUNK_SIZE)) == NULL)
 257                                         out_of_memory("recv_deflated_token");
 258                                 init_done = 1;
 259                         } else {
 260                                 inflateReset(&rx_strm);
 261                         }
 262                         recv_state = r_idle;
 263                         rx_token = 0;
 264                         break;
 265
 266                 case r_idle:
 267                 case r_inflated:
 268                         if (saved_flag) {
 269                                 flag = saved_flag & 0xff;
 270                                 saved_flag = 0;
 271                         } else
 272                                 flag = read_byte(f);
 273                         if ((flag & 0xC0) == DEFLATED_DATA) {
 274                                 n = ((flag & 0x3f) << 8) + read_byte(f);
 275                                 read_buf(f, cbuf, n);
 276                                 rx_strm.next_in = (Bytef *)cbuf;
 277                                 rx_strm.avail_in = n;
 278                                 recv_state = r_inflating;
 279                                 break;
 280                         }
 281                         if (recv_state == r_inflated) {
 282                                 /* check previous inflated stuff ended correctly */
 283                                 rx_strm.avail_in = 0;
 284                                 rx_strm.next_out = (Bytef *)dbuf;
 285                                 rx_strm.avail_out = CHUNK_SIZE;
 286                                 r = inflate(&rx_strm, Z_SYNC_FLUSH);
 287                                 n = CHUNK_SIZE - rx_strm.avail_out;
 288                                 /*
 289                                  * Z_BUF_ERROR just means no progress was
 290                                  * made, i.e. the decompressor didn't have
 291                                  * any pending output for us.
 292                                  */
 293                                 if (r != Z_OK && r != Z_BUF_ERROR) {
 294                                         rprintf(FERROR, "inflate flush returned %d (%d bytes)\n",
 295                                                 r, n);
 296                                         exit_cleanup(1);
 297                                 }
 298                                 if (n != 0 && r != Z_BUF_ERROR) {
 299                                         /* have to return some more data and
 300                                            save the flag for later. */
 301                                         saved_flag = flag + 0x10000;
 302                                         *data = dbuf;
 303                                         return n;
 304                                 }
 305                                 /*
 306                                  * At this point the decompressor should
 307                                  * be expecting to see the 0, 0, ff, ff bytes.
 308                                  */
 309                                 if (!inflateSyncPoint(&rx_strm)) {
 310                                         rprintf(FERROR, "decompressor lost sync!\n");
 311                                         exit_cleanup(1);
 312                                 }
 313                                 rx_strm.avail_in = 4;
 314                                 rx_strm.next_in = (Bytef *)cbuf;
 315                                 cbuf[0] = cbuf[1] = 0;
 316                                 cbuf[2] = cbuf[3] = 0xff;
 317                                 inflate(&rx_strm, Z_SYNC_FLUSH);
 318                                 recv_state = r_idle;
 319                         }
 320                         if (flag == END_FLAG) {
 321                                 /* that's all folks */
 322                                 recv_state = r_init;
 323                                 return 0;
 324                         }
 325
 326                         /* here we have a token of some kind */
 327                         if (flag & TOKEN_REL) {
 328                                 rx_token += flag & 0x3f;
 329                                 flag >>= 6;
 330                         } else
 331                                 rx_token = read_int(f);
 332                         if (flag & 1) {
 333                                 rx_run = read_byte(f);
 334                                 rx_run += read_byte(f) << 8;
 335                                 recv_state = r_running;
 336                         }
 337                         return -1 - rx_token;
 338
 339                 case r_inflating:
 340                         rx_strm.next_out = (Bytef *)dbuf;
 341                         rx_strm.avail_out = CHUNK_SIZE;
 342                         r = inflate(&rx_strm, Z_NO_FLUSH);
 343                         n = CHUNK_SIZE - rx_strm.avail_out;
 344                         if (r != Z_OK) {
 345                                 rprintf(FERROR, "inflate returned %d (%d bytes)\n", r, n);
 346                                 exit_cleanup(1);
 347                         }
 348                         if (rx_strm.avail_in == 0)
 349                                 recv_state = r_inflated;
 350                         if (n != 0) {
 351                                 *data = dbuf;
 352                                 return n;
 353                         }
 354                         break;
 355
 356                 case r_running:
 357                         ++rx_token;
 358                         if (--rx_run == 0)
 359                                 recv_state = r_idle;
 360                         return -1 - rx_token;
 361                 }
 362         }
 363 }
 364
 365 /*
 366  * put the data corresponding to a token that we've just returned
 367  * from recv_deflated_token into the decompressor's history buffer.
 368  */
 369 void
 370 see_deflate_token(char *buf, int len)
 371 {
 372         int r, blklen;
 373         unsigned char hdr[5];
 374
 375         rx_strm.avail_in = 0;
 376         blklen = 0;
 377         hdr[0] = 0;
 378         do {
 379                 if (rx_strm.avail_in == 0 && len != 0) {
 380                         if (blklen == 0) {
 381                                 /* Give it a fake stored-block header. */
 382                                 rx_strm.next_in = (Bytef *)hdr;
 383                                 rx_strm.avail_in = 5;
 384                                 blklen = len;
 385                                 if (blklen > 0xffff)
 386                                         blklen = 0xffff;
 387                                 hdr[1] = blklen;
 388                                 hdr[2] = blklen >> 8;
 389                                 hdr[3] = ~hdr[1];
 390                                 hdr[4] = ~hdr[2];
 391                         } else {
 392                                 rx_strm.next_in = (Bytef *)buf;
 393                                 rx_strm.avail_in = blklen;
 394                                 len -= blklen;
 395                                 blklen = 0;
 396                         }
 397                 }
 398                 rx_strm.next_out = (Bytef *)dbuf;
 399                 rx_strm.avail_out = CHUNK_SIZE;
 400                 r = inflate(&rx_strm, Z_SYNC_FLUSH);
 401                 if (r != Z_OK) {
 402                         rprintf(FERROR, "inflate (token) returned %d\n", r);
 403                         exit_cleanup(1);
 404                 }
 405         } while (len || rx_strm.avail_out == 0);
 406 }
 407
 408 /*
 409  * transmit a verbatim buffer of length n followed by a token
 410  * If token == -1 then we have reached EOF
 411  * If n == 0 then don't send a buffer
 412  */
 413 void send_token(int f,int token,struct map_struct *buf,OFF_T offset,
 414                 int n,int toklen)
 415 {
 416         if (!do_compression) {
 417                 simple_send_token(f,token,buf,offset,n);
 418         } else {
 419                 send_deflated_token(f, token, buf, offset, n, toklen);
 420         }
 421 }
 422
 423
 424 /*
 425  * receive a token or buffer from the other end. If the reurn value is >0 then
 426  * it is a data buffer of that length, and *data will point at the data.
 427  * if the return value is -i then it represents token i-1
 428  * if the return value is 0 then the end has been reached
 429  */
 430 int recv_token(int f,char **data)
 431 {
 432         int tok;
 433
 434         if (!do_compression) {
 435                 tok = simple_recv_token(f,data);
 436         } else {
 437                 tok = recv_deflated_token(f, data);
 438         }
 439         return tok;
 440 }
 441
 442 /*
 443  * look at the data corresponding to a token, if necessary
 444  */
 445 void see_token(char *data, int toklen)
 446 {
 447         if (do_compression)
 448                 see_deflate_token(data, toklen);
 449 }