compat.c

   1 /*
   2  * Compatibility routines for older rsync protocol versions.
   3  *
   4  * Copyright (C) Andrew Tridgell 1996
   5  * Copyright (C) Paul Mackerras 1996
   6  * Copyright (C) 2004-2020 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
  25 extern int am_server;
  26 extern int am_sender;
  27 extern int local_server;
  28 extern int inplace;
  29 extern int recurse;
  30 extern int use_qsort;
  31 extern int allow_inc_recurse;
  32 extern int preallocate_files;
  33 extern int append_mode;
  34 extern int fuzzy_basis;
  35 extern int read_batch;
  36 extern int write_batch;
  37 extern int delay_updates;
  38 extern int checksum_seed;
  39 extern int basis_dir_cnt;
  40 extern int prune_empty_dirs;
  41 extern int protocol_version;
  42 extern int protect_args;
  43 extern int preserve_uid;
  44 extern int preserve_gid;
  45 extern int preserve_atimes;
  46 extern int preserve_acls;
  47 extern int preserve_xattrs;
  48 extern int xfer_flags_as_varint;
  49 extern int need_messages_from_generator;
  50 extern int delete_mode, delete_before, delete_during, delete_after;
  51 extern int do_compression;
  52 extern int do_compression_level;
  53 extern char *shell_cmd;
  54 extern char *partial_dir;
  55 extern char *files_from;
  56 extern char *filesfrom_host;
  57 extern const char *checksum_choice;
  58 extern const char *compress_choice;
  59 extern filter_rule_list filter_list;
  60 extern int need_unsorted_flist;
  61 #ifdef ICONV_OPTION
  62 extern iconv_t ic_send, ic_recv;
  63 extern char *iconv_opt;
  64 #endif
  65 extern struct name_num_obj valid_checksums;
  66
  67 int remote_protocol = 0;
  68 int file_extra_cnt = 0; /* count of file-list extras that everyone gets */
  69 int inc_recurse = 0;
  70 int compat_flags = 0;
  71 int use_safe_inc_flist = 0;
  72 int want_xattr_optim = 0;
  73 int proper_seed_order = 0;
  74 int inplace_partial = 0;
  75 int do_negotiated_strings = 0;
  76 int xmit_id0_names = 0;
  77
  78 /* These index values are for the file-list's extra-attribute array. */
  79 int pathname_ndx, depth_ndx, atimes_ndx, uid_ndx, gid_ndx, acls_ndx, xattrs_ndx, unsort_ndx;
  80
  81 int receiver_symlink_times = 0; /* receiver can set the time on a symlink */
  82 int sender_symlink_iconv = 0;   /* sender should convert symlink content */
  83
  84 #ifdef ICONV_OPTION
  85 int filesfrom_convert = 0;
  86 #endif
  87
  88 #define MAX_NSTR_STRLEN 256
  89
  90 struct name_num_obj valid_compressions = {
  91         "compress", NULL, NULL, 0, 0, {
  92 #ifdef SUPPORT_ZSTD
  93                 { CPRES_ZSTD, "zstd", NULL },
  94 #endif
  95 #ifdef SUPPORT_LZ4
  96                 { CPRES_LZ4, "lz4", NULL },
  97 #endif
  98                 { CPRES_ZLIBX, "zlibx", NULL },
  99                 { CPRES_ZLIB, "zlib", NULL },
 100                 { CPRES_NONE, "none", NULL },
 101                 { 0, NULL, NULL }
 102         }
 103 };
 104
 105 #define CF_INC_RECURSE   (1<<0)
 106 #define CF_SYMLINK_TIMES (1<<1)
 107 #define CF_SYMLINK_ICONV (1<<2)
 108 #define CF_SAFE_FLIST    (1<<3)
 109 #define CF_AVOID_XATTR_OPTIM (1<<4)
 110 #define CF_CHKSUM_SEED_FIX (1<<5)
 111 #define CF_INPLACE_PARTIAL_DIR (1<<6)
 112 #define CF_VARINT_FLIST_FLAGS (1<<7)
 113 #define CF_ID0_NAMES (1<<8)
 114
 115 static const char *client_info;
 116
 117 /* The server makes sure that if either side only supports a pre-release
 118  * version of a protocol, that both sides must speak a compatible version
 119  * of that protocol for it to be advertised as available. */
 120 static void check_sub_protocol(void)
 121 {
 122         char *dot;
 123         int their_protocol, their_sub;
 124 #if SUBPROTOCOL_VERSION != 0
 125         int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
 126 #else
 127         int our_sub = 0;
 128 #endif
 129
 130         /* client_info starts with VER.SUB string if client is a pre-release. */
 131         if (!(their_protocol = atoi(client_info))
 132          || !(dot = strchr(client_info, '.'))
 133          || !(their_sub = atoi(dot+1))) {
 134 #if SUBPROTOCOL_VERSION != 0
 135                 if (our_sub)
 136                         protocol_version--;
 137 #endif
 138                 return;
 139         }
 140
 141         if (their_protocol < protocol_version) {
 142                 if (their_sub)
 143                         protocol_version = their_protocol - 1;
 144                 return;
 145         }
 146
 147         if (their_protocol > protocol_version)
 148                 their_sub = 0; /* 0 == final version of older protocol */
 149         if (their_sub != our_sub)
 150                 protocol_version--;
 151 }
 152
 153 void set_allow_inc_recurse(void)
 154 {
 155         client_info = shell_cmd ? shell_cmd : "";
 156
 157         if (!recurse || use_qsort)
 158                 allow_inc_recurse = 0;
 159         else if (!am_sender
 160          && (delete_before || delete_after
 161           || delay_updates || prune_empty_dirs))
 162                 allow_inc_recurse = 0;
 163         else if (am_server && !local_server
 164          && (strchr(client_info, 'i') == NULL))
 165                 allow_inc_recurse = 0;
 166 }
 167
 168 void parse_compress_choice(int final_call)
 169 {
 170         if (valid_compressions.negotiated_name)
 171                 do_compression = valid_compressions.negotiated_num;
 172         else if (compress_choice) {
 173                 struct name_num_item *nni = get_nni_by_name(&valid_compressions, compress_choice, -1);
 174                 if (!nni) {
 175                         rprintf(FERROR, "unknown compress name: %s\n", compress_choice);
 176                         exit_cleanup(RERR_UNSUPPORTED);
 177                 }
 178                 do_compression = nni->num;
 179                 if (am_server)
 180                         validate_choice_vs_env(NSTR_COMPRESS, do_compression, -1);
 181         } else if (do_compression)
 182                 do_compression = CPRES_ZLIB;
 183         else
 184                 do_compression = CPRES_NONE;
 185
 186         if (do_compression != CPRES_NONE && final_call)
 187                 init_compression_level(); /* There's a chance this might turn compression off! */
 188
 189         if (do_compression == CPRES_NONE)
 190                 compress_choice = NULL;
 191
 192         /* Snag the compression name for both write_batch's option output & the following debug output. */
 193         if (valid_compressions.negotiated_name)
 194                 compress_choice = valid_compressions.negotiated_name;
 195         else if (compress_choice == NULL) {
 196                 struct name_num_item *nni = get_nni_by_num(&valid_compressions, do_compression);
 197                 compress_choice = nni ? nni->name : "UNKNOWN";
 198         }
 199
 200         if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)
 201          && (do_compression != CPRES_NONE || do_compression_level != CLVL_NOT_SPECIFIED)) {
 202                 rprintf(FINFO, "%s%s compress: %s (level %d)\n",
 203                         am_server ? "Server" : "Client",
 204                         valid_compressions.negotiated_name ? " negotiated" : "",
 205                         compress_choice, do_compression_level);
 206         }
 207 }
 208
 209 struct name_num_item *get_nni_by_name(struct name_num_obj *nno, const char *name, int len)
 210 {
 211         struct name_num_item *nni;
 212
 213         if (len < 0)
 214                 len = strlen(name);
 215
 216         for (nni = nno->list; nni->name; nni++) {
 217                 if (strncasecmp(name, nni->name, len) == 0 && nni->name[len] == '\0')
 218                         return nni;
 219         }
 220
 221         return NULL;
 222 }
 223
 224 struct name_num_item *get_nni_by_num(struct name_num_obj *nno, int num)
 225 {
 226         struct name_num_item *nni;
 227
 228         for (nni = nno->list; nni->name; nni++) {
 229                 if (num == nni->num)
 230                         return nni;
 231         }
 232
 233         return NULL;
 234 }
 235
 236 static void init_nno_saw(struct name_num_obj *nno, int val)
 237 {
 238         struct name_num_item *nni;
 239         int cnt;
 240
 241         if (!nno->saw_len) {
 242                 for (nni = nno->list; nni->name; nni++) {
 243                         if (nni->num >= nno->saw_len)
 244                                 nno->saw_len = nni->num + 1;
 245                 }
 246         }
 247
 248         if (!nno->saw) {
 249                 nno->saw = new_array0(uchar, nno->saw_len);
 250
 251                 /* We'll take this opportunity to make sure that the main_name values are set right. */
 252                 for (cnt = 1, nni = nno->list; nni->name; nni++, cnt++) {
 253                         if (nno->saw[nni->num])
 254                                 nni->main_name = nno->list[nno->saw[nni->num]-1].name;
 255                         else
 256                                 nno->saw[nni->num] = cnt;
 257                 }
 258         }
 259
 260         memset(nno->saw, val, nno->saw_len);
 261 }
 262
 263 /* Simplify the user-provided string so that it contains valid names without any duplicates.
 264  * It also sets the "saw" flags to a 1-relative count of which name was seen first. */
 265 static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf, int tobuf_len)
 266 {
 267         char *to = tobuf, *tok = NULL;
 268         int saw_tok = 0, cnt = 0;
 269
 270         while (1) {
 271                 int at_space = isSpace(from);
 272                 char ch = *from++;
 273                 if (ch == '&')
 274                         ch = '\0';
 275                 if (!ch || at_space) {
 276                         if (tok) {
 277                                 struct name_num_item *nni = get_nni_by_name(nno, tok, to - tok);
 278                                 if (nni && !nno->saw[nni->num]) {
 279                                         nno->saw[nni->num] = ++cnt;
 280                                         if (nni->main_name) {
 281                                                 to = tok + strlcpy(tok, nni->main_name, tobuf_len - (tok - tobuf));
 282                                                 if (to - tobuf >= tobuf_len) {
 283                                                         to = tok - 1;
 284                                                         break;
 285                                                 }
 286                                         }
 287                                 } else
 288                                         to = tok - (tok != tobuf);
 289                                 saw_tok = 1;
 290                                 tok = NULL;
 291                         }
 292                         if (!ch)
 293                                 break;
 294                         continue;
 295                 }
 296                 if (!tok) {
 297                         if (to != tobuf)
 298                                 *to++ = ' ';
 299                         tok = to;
 300                 }
 301                 if (to - tobuf >= tobuf_len - 1) {
 302                         to = tok - (tok != tobuf);
 303                         break;
 304                 }
 305                 *to++ = ch;
 306         }
 307         *to = '\0';
 308
 309         if (saw_tok && to == tobuf)
 310                 return strlcpy(tobuf, "INVALID", MAX_NSTR_STRLEN);
 311
 312         return to - tobuf;
 313 }
 314
 315 /* This routine is always called with a tmpbuf of MAX_NSTR_STRLEN length, but the
 316  * buffer may be pre-populated with a "len" length string to use OR a len of -1
 317  * to tell us to read a string from the fd. */
 318 static void recv_negotiate_str(int f_in, struct name_num_obj *nno, char *tmpbuf, int len)
 319 {
 320         struct name_num_item *ret = NULL;
 321
 322         if (len < 0)
 323                 len = read_vstring(f_in, tmpbuf, MAX_NSTR_STRLEN);
 324
 325         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 326                 if (am_server)
 327                         rprintf(FINFO, "Client %s list (on server): %s\n", nno->type, tmpbuf);
 328                 else
 329                         rprintf(FINFO, "Server %s list (on client): %s\n", nno->type, tmpbuf);
 330         }
 331
 332         if (len > 0) {
 333                 struct name_num_item *nni;
 334                 int best = nno->saw_len; /* We want best == 1 from the client list, so start with a big number. */
 335                 char *space, *tok = tmpbuf;
 336                 while (tok) {
 337                         while (*tok == ' ') tok++; /* Should be unneeded... */
 338                         if (!*tok)
 339                                 break;
 340                         if ((space = strchr(tok, ' ')) != NULL)
 341                                 *space = '\0';
 342                         nni = get_nni_by_name(nno, tok, -1);
 343                         if (space) {
 344                                 *space = ' ';
 345                                 tok = space + 1;
 346                         } else
 347                                 tok = NULL;
 348                         if (!nni || !nno->saw[nni->num] || best <= nno->saw[nni->num])
 349                                 continue;
 350                         ret = nni;
 351                         best = nno->saw[nni->num];
 352                         if (best == 1 || am_server) /* The server side stops at the first acceptable client choice */
 353                                 break;
 354                 }
 355                 if (ret) {
 356                         free(nno->saw);
 357                         nno->saw = NULL;
 358                         nno->negotiated_name = ret->main_name ? ret->main_name : ret->name;
 359                         nno->negotiated_num = ret->num;
 360                         return;
 361                 }
 362         }
 363
 364         if (!am_server || !do_negotiated_strings) {
 365                 char *cp = tmpbuf;
 366                 int j;
 367                 rprintf(FERROR, "Failed to negotiate a %s choice.\n", nno->type);
 368                 rprintf(FERROR, "%s list: %s\n", am_server ? "Client" : "Server", tmpbuf);
 369                 /* Recreate our original list from the saw values. This can't overflow our huge
 370                  * buffer because we don't have enough valid entries to get anywhere close. */
 371                 for (j = 1, *cp = '\0'; j <= nno->saw_len; j++) {
 372                         struct name_num_item *nni;
 373                         for (nni = nno->list; nni->name; nni++) {
 374                                 if (nno->saw[nni->num] == j) {
 375                                         *cp++ = ' ';
 376                                         cp += strlcpy(cp, nni->name, MAX_NSTR_STRLEN - (cp - tmpbuf));
 377                                         break;
 378                                 }
 379                         }
 380                 }
 381                 if (!*tmpbuf)
 382                         strlcpy(cp, " INVALID", MAX_NSTR_STRLEN);
 383                 rprintf(FERROR, "%s list:%s\n", am_server ? "Server" : "Client", tmpbuf);
 384         }
 385
 386         exit_cleanup(RERR_UNSUPPORTED);
 387 }
 388
 389 static const char *getenv_nstr(int ntype)
 390 {
 391         const char *env_str = getenv(ntype == NSTR_COMPRESS ? "RSYNC_COMPRESS_LIST" : "RSYNC_CHECKSUM_LIST");
 392
 393         /* When writing a batch file, we always negotiate an old-style choice. */
 394         if (write_batch)
 395                 env_str = ntype == NSTR_COMPRESS ? "zlib" : protocol_version >= 30 ? "md5" : "md4";
 396
 397         if (am_server && env_str) {
 398                 char *cp = strchr(env_str, '&');
 399                 if (cp)
 400                         env_str = cp + 1;
 401         }
 402
 403         return env_str;
 404 }
 405
 406 void validate_choice_vs_env(int ntype, int num1, int num2)
 407 {
 408         struct name_num_obj *nno = ntype == NSTR_COMPRESS ? &valid_compressions : &valid_checksums;
 409         const char *list_str = getenv_nstr(ntype);
 410         char tmpbuf[MAX_NSTR_STRLEN];
 411
 412         if (!list_str)
 413                 return;
 414
 415         while (isSpace(list_str)) list_str++;
 416
 417         if (!*list_str)
 418                 return;
 419
 420         init_nno_saw(nno, 0);
 421         parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 422
 423         if (ntype == NSTR_CHECKSUM) /* If "md4" is in the env list, all the old MD4 choices are OK too. */
 424                 nno->saw[CSUM_MD4_ARCHAIC] = nno->saw[CSUM_MD4_BUSTED] = nno->saw[CSUM_MD4_OLD] = nno->saw[CSUM_MD4];
 425
 426         if (!nno->saw[num1] || (num2 >= 0 && !nno->saw[num2])) {
 427                 rprintf(FERROR, "Your --%s-choice value (%s) was refused by the server.\n",
 428                         ntype == NSTR_COMPRESS ? "compress" : "checksum",
 429                         ntype == NSTR_COMPRESS ? compress_choice : checksum_choice);
 430                 exit_cleanup(RERR_UNSUPPORTED);
 431         }
 432
 433         free(nno->saw);
 434         nno->saw = NULL;
 435 }
 436
 437 /* The saw buffer is initialized and used to store ordinal values from 1 to N
 438  * for the order of the args in the array.  If dup_markup == '\0', duplicates
 439  * are removed otherwise the char is prefixed to the duplicate term and, if it
 440  * is an opening paren/bracket/brace, the matching closing char is suffixed.
 441  * "none" is removed on the client side unless dup_markup != '\0'. */
 442 int get_default_nno_list(struct name_num_obj *nno, char *to_buf, int to_buf_len, char dup_markup)
 443 {
 444         struct name_num_item *nni;
 445         int len = 0, cnt = 0;
 446         char delim = '\0', post_delim;
 447
 448         switch (dup_markup) {
 449         case '(': post_delim = ')'; break;
 450         case '[': post_delim = ']'; break;
 451         case '{': post_delim = '}'; break;
 452         default: post_delim = '\0'; break;
 453         }
 454
 455         init_nno_saw(nno, 0);
 456
 457         for (nni = nno->list, len = 0; nni->name; nni++) {
 458                 if (nni->main_name) {
 459                         if (!dup_markup)
 460                                 continue;
 461                         delim = dup_markup;
 462                 }
 463                 if (nni->num == 0 && !am_server && !dup_markup)
 464                         continue;
 465                 if (len)
 466                         to_buf[len++]= ' ';
 467                 if (delim) {
 468                         to_buf[len++]= delim;
 469                         delim = post_delim;
 470                 }
 471                 len += strlcpy(to_buf+len, nni->name, to_buf_len - len);
 472                 if (len >= to_buf_len - 3)
 473                         exit_cleanup(RERR_UNSUPPORTED); /* IMPOSSIBLE... */
 474                 if (delim) {
 475                         to_buf[len++]= delim;
 476                         delim = '\0';
 477                 }
 478                 nno->saw[nni->num] = ++cnt;
 479         }
 480
 481         return len;
 482 }
 483
 484 static void send_negotiate_str(int f_out, struct name_num_obj *nno, int ntype)
 485 {
 486         char tmpbuf[MAX_NSTR_STRLEN];
 487         const char *list_str = getenv_nstr(ntype);
 488         int len;
 489
 490         if (list_str && *list_str) {
 491                 init_nno_saw(nno, 0);
 492                 len = parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 493                 list_str = tmpbuf;
 494         } else
 495                 list_str = NULL;
 496
 497         if (!list_str || !*list_str)
 498                 len = get_default_nno_list(nno, tmpbuf, MAX_NSTR_STRLEN, '\0');
 499
 500         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 501                 if (am_server)
 502                         rprintf(FINFO, "Server %s list (on server): %s\n", nno->type, tmpbuf);
 503                 else
 504                         rprintf(FINFO, "Client %s list (on client): %s\n", nno->type, tmpbuf);
 505         }
 506
 507         /* Each side sends their list of valid names to the other side and then both sides
 508          * pick the first name in the client's list that is also in the server's list. */
 509         if (do_negotiated_strings)
 510                 write_vstring(f_out, tmpbuf, len);
 511 }
 512
 513 static void negotiate_the_strings(int f_in, int f_out)
 514 {
 515         /* We send all the negotiation strings before we start to read them to help avoid a slow startup. */
 516
 517         if (!checksum_choice)
 518                 send_negotiate_str(f_out, &valid_checksums, NSTR_CHECKSUM);
 519
 520         if (do_compression && !compress_choice)
 521                 send_negotiate_str(f_out, &valid_compressions, NSTR_COMPRESS);
 522
 523         if (valid_checksums.saw) {
 524                 char tmpbuf[MAX_NSTR_STRLEN];
 525                 int len;
 526                 if (do_negotiated_strings)
 527                         len = -1;
 528                 else
 529                         len = strlcpy(tmpbuf, protocol_version >= 30 ? "md5" : "md4", MAX_NSTR_STRLEN);
 530                 recv_negotiate_str(f_in, &valid_checksums, tmpbuf, len);
 531         }
 532
 533         if (valid_compressions.saw) {
 534                 char tmpbuf[MAX_NSTR_STRLEN];
 535                 int len;
 536                 if (do_negotiated_strings)
 537                         len = -1;
 538                 else
 539                         len = strlcpy(tmpbuf, "zlib", MAX_NSTR_STRLEN);
 540                 recv_negotiate_str(f_in, &valid_compressions, tmpbuf, len);
 541         }
 542
 543         /* If the other side is too old to negotiate, the above steps just made sure that
 544          * the env didn't disallow the old algorithm. Mark things as non-negotiated. */
 545         if (!do_negotiated_strings)
 546                 valid_checksums.negotiated_name = valid_compressions.negotiated_name = NULL;
 547 }
 548
 549 void setup_protocol(int f_out,int f_in)
 550 {
 551         assert(file_extra_cnt == 0);
 552         assert(EXTRA64_CNT == 2 || EXTRA64_CNT == 1);
 553
 554         /* All int64 values must be set first so that they are guaranteed to be
 555          * aligned for direct int64-pointer memory access. */
 556         if (preserve_atimes)
 557                 atimes_ndx = (file_extra_cnt += EXTRA64_CNT);
 558         if (am_sender) /* This is most likely in the in64 union as well. */
 559                 pathname_ndx = (file_extra_cnt += PTR_EXTRA_CNT);
 560         else
 561                 depth_ndx = ++file_extra_cnt;
 562         if (preserve_uid)
 563                 uid_ndx = ++file_extra_cnt;
 564         if (preserve_gid)
 565                 gid_ndx = ++file_extra_cnt;
 566         if (preserve_acls && !am_sender)
 567                 acls_ndx = ++file_extra_cnt;
 568         if (preserve_xattrs)
 569                 xattrs_ndx = ++file_extra_cnt;
 570
 571         if (am_server)
 572                 set_allow_inc_recurse();
 573
 574         if (remote_protocol == 0) {
 575                 if (am_server && !local_server)
 576                         check_sub_protocol();
 577                 if (!read_batch)
 578                         write_int(f_out, protocol_version);
 579                 remote_protocol = read_int(f_in);
 580                 if (protocol_version > remote_protocol)
 581                         protocol_version = remote_protocol;
 582         }
 583         if (read_batch && remote_protocol > protocol_version) {
 584                 rprintf(FERROR, "The protocol version in the batch file is too new (%d > %d).\n",
 585                         remote_protocol, protocol_version);
 586                 exit_cleanup(RERR_PROTOCOL);
 587         }
 588
 589         if (DEBUG_GTE(PROTO, 1)) {
 590                 rprintf(FINFO, "(%s) Protocol versions: remote=%d, negotiated=%d\n",
 591                         am_server? "Server" : "Client", remote_protocol, protocol_version);
 592         }
 593         if (remote_protocol < MIN_PROTOCOL_VERSION
 594          || remote_protocol > MAX_PROTOCOL_VERSION) {
 595                 rprintf(FERROR,"protocol version mismatch -- is your shell clean?\n");
 596                 rprintf(FERROR,"(see the rsync man page for an explanation)\n");
 597                 exit_cleanup(RERR_PROTOCOL);
 598         }
 599         if (remote_protocol < OLD_PROTOCOL_VERSION) {
 600                 rprintf(FINFO,"%s is very old version of rsync, upgrade recommended.\n",
 601                         am_server? "Client" : "Server");
 602         }
 603         if (protocol_version < MIN_PROTOCOL_VERSION) {
 604                 rprintf(FERROR, "--protocol must be at least %d on the %s.\n",
 605                         MIN_PROTOCOL_VERSION, am_server? "Server" : "Client");
 606                 exit_cleanup(RERR_PROTOCOL);
 607         }
 608         if (protocol_version > PROTOCOL_VERSION) {
 609                 rprintf(FERROR, "--protocol must be no more than %d on the %s.\n",
 610                         PROTOCOL_VERSION, am_server? "Server" : "Client");
 611                 exit_cleanup(RERR_PROTOCOL);
 612         }
 613         if (read_batch)
 614                 check_batch_flags();
 615
 616 #ifndef SUPPORT_PREALLOCATION
 617         if (preallocate_files && !am_sender) {
 618                 rprintf(FERROR, "preallocation is not supported on this %s\n",
 619                         am_server ? "Server" : "Client");
 620                 exit_cleanup(RERR_SYNTAX);
 621         }
 622 #endif
 623
 624         if (protocol_version < 30) {
 625                 if (append_mode == 1)
 626                         append_mode = 2;
 627                 if (preserve_acls && !local_server) {
 628                         rprintf(FERROR,
 629                                 "--acls requires protocol 30 or higher"
 630                                 " (negotiated %d).\n",
 631                                 protocol_version);
 632                         exit_cleanup(RERR_PROTOCOL);
 633                 }
 634                 if (preserve_xattrs && !local_server) {
 635                         rprintf(FERROR,
 636                                 "--xattrs requires protocol 30 or higher"
 637                                 " (negotiated %d).\n",
 638                                 protocol_version);
 639                         exit_cleanup(RERR_PROTOCOL);
 640                 }
 641         }
 642
 643         if (delete_mode && !(delete_before+delete_during+delete_after)) {
 644                 if (protocol_version < 30)
 645                         delete_before = 1;
 646                 else
 647                         delete_during = 1;
 648         }
 649
 650         if (protocol_version < 29) {
 651                 if (fuzzy_basis) {
 652                         rprintf(FERROR,
 653                                 "--fuzzy requires protocol 29 or higher"
 654                                 " (negotiated %d).\n",
 655                                 protocol_version);
 656                         exit_cleanup(RERR_PROTOCOL);
 657                 }
 658
 659                 if (basis_dir_cnt && inplace) {
 660                         rprintf(FERROR,
 661                                 "%s with --inplace requires protocol 29 or higher"
 662                                 " (negotiated %d).\n",
 663                                 alt_dest_opt(0), protocol_version);
 664                         exit_cleanup(RERR_PROTOCOL);
 665                 }
 666
 667                 if (basis_dir_cnt > 1) {
 668                         rprintf(FERROR,
 669                                 "Using more than one %s option requires protocol"
 670                                 " 29 or higher (negotiated %d).\n",
 671                                 alt_dest_opt(0), protocol_version);
 672                         exit_cleanup(RERR_PROTOCOL);
 673                 }
 674
 675                 if (prune_empty_dirs) {
 676                         rprintf(FERROR,
 677                                 "--prune-empty-dirs requires protocol 29 or higher"
 678                                 " (negotiated %d).\n",
 679                                 protocol_version);
 680                         exit_cleanup(RERR_PROTOCOL);
 681                 }
 682         } else if (protocol_version >= 30) {
 683                 if (am_server) {
 684                         compat_flags = allow_inc_recurse ? CF_INC_RECURSE : 0;
 685 #ifdef CAN_SET_SYMLINK_TIMES
 686                         compat_flags |= CF_SYMLINK_TIMES;
 687 #endif
 688 #ifdef ICONV_OPTION
 689                         compat_flags |= CF_SYMLINK_ICONV;
 690 #endif
 691                         if (local_server || strchr(client_info, 'f') != NULL)
 692                                 compat_flags |= CF_SAFE_FLIST;
 693                         if (local_server || strchr(client_info, 'x') != NULL)
 694                                 compat_flags |= CF_AVOID_XATTR_OPTIM;
 695                         if (local_server || strchr(client_info, 'C') != NULL)
 696                                 compat_flags |= CF_CHKSUM_SEED_FIX;
 697                         if (local_server || strchr(client_info, 'I') != NULL)
 698                                 compat_flags |= CF_INPLACE_PARTIAL_DIR;
 699                         if (local_server || strchr(client_info, 'u') != NULL)
 700                                 compat_flags |= CF_ID0_NAMES;
 701                         if (local_server || strchr(client_info, 'v') != NULL) {
 702                                 do_negotiated_strings = 1;
 703                                 compat_flags |= CF_VARINT_FLIST_FLAGS;
 704                         }
 705                         if (strchr(client_info, 'V') != NULL) { /* Support a pre-release 'V' that got superseded */
 706                                 if (!write_batch)
 707                                         compat_flags |= CF_VARINT_FLIST_FLAGS;
 708                                 write_byte(f_out, compat_flags);
 709                         } else
 710                                 write_varint(f_out, compat_flags);
 711                 } else { /* read_varint() is compatible with the older write_byte() when the 0x80 bit isn't on. */
 712                         compat_flags = read_varint(f_in);
 713                         if  (compat_flags & CF_VARINT_FLIST_FLAGS)
 714                                 do_negotiated_strings = 1;
 715                 }
 716                 /* The inc_recurse var MUST be set to 0 or 1. */
 717                 inc_recurse = compat_flags & CF_INC_RECURSE ? 1 : 0;
 718                 want_xattr_optim = protocol_version >= 31 && !(compat_flags & CF_AVOID_XATTR_OPTIM);
 719                 proper_seed_order = compat_flags & CF_CHKSUM_SEED_FIX ? 1 : 0;
 720                 xfer_flags_as_varint = compat_flags & CF_VARINT_FLIST_FLAGS ? 1 : 0;
 721                 xmit_id0_names = compat_flags & CF_ID0_NAMES ? 1 : 0;
 722                 if (am_sender) {
 723                         receiver_symlink_times = am_server
 724                             ? strchr(client_info, 'L') != NULL
 725                             : !!(compat_flags & CF_SYMLINK_TIMES);
 726                 }
 727 #ifdef CAN_SET_SYMLINK_TIMES
 728                 else
 729                         receiver_symlink_times = 1;
 730 #endif
 731 #ifdef ICONV_OPTION
 732                 sender_symlink_iconv = iconv_opt && (am_server
 733                     ? local_server || strchr(client_info, 's') != NULL
 734                     : !!(compat_flags & CF_SYMLINK_ICONV));
 735 #endif
 736                 if (inc_recurse && !allow_inc_recurse) {
 737                         /* This should only be able to happen in a batch. */
 738                         fprintf(stderr,
 739                                 "Incompatible options specified for inc-recursive %s.\n",
 740                                 read_batch ? "batch file" : "connection");
 741                         exit_cleanup(RERR_SYNTAX);
 742                 }
 743                 use_safe_inc_flist = (compat_flags & CF_SAFE_FLIST) || protocol_version >= 31;
 744                 need_messages_from_generator = 1;
 745                 if (compat_flags & CF_INPLACE_PARTIAL_DIR)
 746                         inplace_partial = 1;
 747 #ifdef CAN_SET_SYMLINK_TIMES
 748         } else if (!am_sender) {
 749                 receiver_symlink_times = 1;
 750 #endif
 751         }
 752
 753         if (read_batch)
 754                 do_negotiated_strings = 0;
 755
 756         if (need_unsorted_flist && (!am_sender || inc_recurse))
 757                 unsort_ndx = ++file_extra_cnt;
 758
 759         if (partial_dir && *partial_dir != '/' && (!am_server || local_server)) {
 760                 int rflags = FILTRULE_NO_PREFIXES | FILTRULE_DIRECTORY;
 761                 if (!am_sender || protocol_version >= 30)
 762                         rflags |= FILTRULE_PERISHABLE;
 763                 parse_filter_str(&filter_list, partial_dir, rule_template(rflags), 0);
 764         }
 765
 766
 767 #ifdef ICONV_OPTION
 768         if (protect_args && files_from) {
 769                 if (am_sender)
 770                         filesfrom_convert = filesfrom_host && ic_send != (iconv_t)-1;
 771                 else
 772                         filesfrom_convert = !filesfrom_host && ic_recv != (iconv_t)-1;
 773         }
 774 #endif
 775
 776         negotiate_the_strings(f_in, f_out);
 777
 778         if (am_server) {
 779                 if (!checksum_seed)
 780                         checksum_seed = time(NULL) ^ (getpid() << 6);
 781                 write_int(f_out, checksum_seed);
 782         } else {
 783                 checksum_seed = read_int(f_in);
 784         }
 785
 786         parse_checksum_choice(1); /* Sets checksum_type & xfersum_type */
 787         parse_compress_choice(1); /* Sets do_compression */
 788
 789         if (write_batch && !am_server)
 790                 write_batch_shell_file();
 791
 792         init_flist();
 793 }