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
  24 extern int am_server;
  25 extern int am_sender;
  26 extern int local_server;
  27 extern int inplace;
  28 extern int recurse;
  29 extern int use_qsort;
  30 extern int allow_inc_recurse;
  31 extern int preallocate_files;
  32 extern int append_mode;
  33 extern int fuzzy_basis;
  34 extern int read_batch;
  35 extern int write_batch;
  36 extern int delay_updates;
  37 extern int checksum_seed;
  38 extern int basis_dir_cnt;
  39 extern int prune_empty_dirs;
  40 extern int protocol_version;
  41 extern int protect_args;
  42 extern int preserve_uid;
  43 extern int preserve_gid;
  44 extern int preserve_atimes;
  45 extern int preserve_acls;
  46 extern int preserve_xattrs;
  47 extern int xfer_flags_as_varint;
  48 extern int need_messages_from_generator;
  49 extern int delete_mode, delete_before, delete_during, delete_after;
  50 extern int do_compression;
  51 extern int do_compression_level;
  52 extern char *shell_cmd;
  53 extern char *partial_dir;
  54 extern char *dest_option;
  55 extern char *files_from;
  56 extern char *filesfrom_host;
  57 extern char *checksum_choice;
  58 extern 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
  77 /* These index values are for the file-list's extra-attribute array. */
  78 int pathname_ndx, depth_ndx, atimes_ndx, uid_ndx, gid_ndx, acls_ndx, xattrs_ndx, unsort_ndx;
  79
  80 int receiver_symlink_times = 0; /* receiver can set the time on a symlink */
  81 int sender_symlink_iconv = 0;   /* sender should convert symlink content */
  82
  83 #ifdef ICONV_OPTION
  84 int filesfrom_convert = 0;
  85 #endif
  86
  87 #define MAX_NSTR_STRLEN 256
  88
  89 struct name_num_obj valid_compressions = {
  90         "compress", NULL, NULL, 0, 0, {
  91                 { CPRES_ZLIBX, "zlibx", NULL },
  92                 { CPRES_ZLIB, "zlib", NULL },
  93 #ifdef SUPPORT_ZSTD
  94                 /* TODO decide where in the default preference order this should go. */
  95                 { CPRES_ZSTD, "zstd", NULL },
  96 #endif
  97 #ifdef SUPPORT_LZ4
  98                 /* TODO decide where in the default preference order this should go. */
  99                 { CPRES_LZ4, "lz4", NULL },
 100 #endif
 101                 { CPRES_NONE, "none", NULL },
 102                 { 0, NULL, NULL }
 103         }
 104 };
 105
 106 #define CF_INC_RECURSE   (1<<0)
 107 #define CF_SYMLINK_TIMES (1<<1)
 108 #define CF_SYMLINK_ICONV (1<<2)
 109 #define CF_SAFE_FLIST    (1<<3)
 110 #define CF_AVOID_XATTR_OPTIM (1<<4)
 111 #define CF_CHKSUM_SEED_FIX (1<<5)
 112 #define CF_INPLACE_PARTIAL_DIR (1<<6)
 113 #define CF_VARINT_FLIST_FLAGS (1<<7)
 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         } else if (do_compression)
 180                 do_compression = CPRES_ZLIB;
 181         else
 182                 do_compression = CPRES_NONE;
 183
 184         if (do_compression != CPRES_NONE && final_call)
 185                 init_compression_level(); /* There's a chance this might turn compression off! */
 186
 187         if (do_compression == CPRES_NONE)
 188                 compress_choice = NULL;
 189
 190         if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)
 191          && (do_compression != CPRES_NONE || do_compression_level != CLVL_NOT_SPECIFIED)) {
 192                 const char *c_s = am_server ? "Server" : "Client";
 193                 if (do_compression != CPRES_NONE && valid_compressions.negotiated_name) {
 194                         rprintf(FINFO, "%s negotiated compress: %s (level %d)\n",
 195                                 c_s, valid_compressions.negotiated_name, do_compression_level);
 196                 } else {
 197                         struct name_num_item *nni = get_nni_by_num(&valid_compressions, do_compression);
 198                         rprintf(FINFO, "%s compress: %s (level %d)\n",
 199                                 c_s, nni ? nni->name : "UNKNOWN", do_compression_level);
 200                 }
 201         }
 202 }
 203
 204 struct name_num_item *get_nni_by_name(struct name_num_obj *nno, const char *name, int len)
 205 {
 206         struct name_num_item *nni;
 207
 208         if (len < 0)
 209                 len = strlen(name);
 210
 211         for (nni = nno->list; nni->name; nni++) {
 212                 if (strncasecmp(name, nni->name, len) == 0 && nni->name[len] == '\0')
 213                         return nni;
 214         }
 215
 216         return NULL;
 217 }
 218
 219 struct name_num_item *get_nni_by_num(struct name_num_obj *nno, int num)
 220 {
 221         struct name_num_item *nni;
 222
 223         for (nni = nno->list; nni->name; nni++) {
 224                 if (num == nni->num)
 225                         return nni;
 226         }
 227
 228         return NULL;
 229 }
 230
 231 static void init_nno_saw(struct name_num_obj *nno, int val)
 232 {
 233         struct name_num_item *nni;
 234         int cnt;
 235
 236         if (!nno->saw_len) {
 237                 for (nni = nno->list; nni->name; nni++) {
 238                         if (nni->num >= nno->saw_len)
 239                                 nno->saw_len = nni->num + 1;
 240                 }
 241         }
 242
 243         if (!nno->saw) {
 244                 if (!(nno->saw = new_array0(uchar, nno->saw_len)))
 245                         out_of_memory("init_nno_saw");
 246
 247                 /* We'll take this opportunity to make sure that the main_name values are set right. */
 248                 for (cnt = 1, nni = nno->list; nni->name; nni++, cnt++) {
 249                         if (nno->saw[nni->num])
 250                                 nni->main_name = nno->list[nno->saw[nni->num]-1].name;
 251                         else
 252                                 nno->saw[nni->num] = cnt;
 253                 }
 254         }
 255
 256         memset(nno->saw, val, nno->saw_len);
 257 }
 258
 259 /* Simplify the user-provided string so that it contains valid names without any duplicates.
 260  * It also sets the "saw" flags to a 1-relative count of which name was seen first. */
 261 static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf, int tobuf_len)
 262 {
 263         char *to = tobuf, *tok = NULL;
 264         int cnt = 0;
 265
 266         while (1) {
 267                 if (*from == ' ' || !*from) {
 268                         if (tok) {
 269                                 struct name_num_item *nni = get_nni_by_name(nno, tok, to - tok);
 270                                 if (nni && !nno->saw[nni->num]) {
 271                                         nno->saw[nni->num] = ++cnt;
 272                                         if (nni->main_name) {
 273                                                 to = tok + strlcpy(tok, nni->main_name, tobuf_len - (tok - tobuf));
 274                                                 if (to - tobuf >= tobuf_len) {
 275                                                         to = tok - 1;
 276                                                         break;
 277                                                 }
 278                                         }
 279                                 } else
 280                                         to = tok - (tok != tobuf);
 281                                 tok = NULL;
 282                         }
 283                         if (!*from++)
 284                                 break;
 285                         continue;
 286                 }
 287                 if (!tok) {
 288                         if (to != tobuf)
 289                                 *to++ = ' ';
 290                         tok = to;
 291                 }
 292                 if (to - tobuf >= tobuf_len - 1) {
 293                         to = tok - (tok != tobuf);
 294                         break;
 295                 }
 296                 *to++ = *from++;
 297         }
 298         *to = '\0';
 299
 300         return to - tobuf;
 301 }
 302
 303 static void recv_negotiate_str(int f_in, struct name_num_obj *nno, char *tmpbuf, int len)
 304 {
 305         struct name_num_item *ret = NULL;
 306
 307         if (len < 0)
 308                 len = read_vstring(f_in, tmpbuf, MAX_NSTR_STRLEN);
 309
 310         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 311                 if (am_server)
 312                         rprintf(FINFO, "Client %s list (on server): %s\n", nno->type, tmpbuf);
 313                 else
 314                         rprintf(FINFO, "Server %s list (on client): %s\n", nno->type, tmpbuf);
 315         }
 316
 317         if (len > 0) {
 318                 int best = nno->saw_len; /* We want best == 1 from the client list, so start with a big number. */
 319                 char *tok;
 320                 if (am_server)
 321                         init_nno_saw(nno, 1); /* Since we're parsing client names, anything we parse first is #1. */
 322                 for (tok = strtok(tmpbuf, " \t"); tok; tok = strtok(NULL, " \t")) {
 323                         struct name_num_item *nni = get_nni_by_name(nno, tok, -1);
 324                         if (!nni || !nno->saw[nni->num] || best <= nno->saw[nni->num])
 325                                 continue;
 326                         ret = nni;
 327                         best = nno->saw[nni->num];
 328                         if (best == 1)
 329                                 break;
 330                 }
 331                 if (ret) {
 332                         free(nno->saw);
 333                         nno->saw = NULL;
 334                         nno->negotiated_name = ret->main_name ? ret->main_name : ret->name;
 335                         nno->negotiated_num = ret->num;
 336                         return;
 337                 }
 338         }
 339
 340         if (!am_server)
 341                 rprintf(FERROR, "Failed to negotiate a common %s\n", nno->type);
 342         exit_cleanup(RERR_UNSUPPORTED);
 343 }
 344
 345 /* The saw buffer is initialized and used to store ordinal values from 1 to N
 346  * for the order of the args in the array.  If dup_markup == '\0', duplicates
 347  * are removed otherwise the char is prefixed to the duplicate term and, if it
 348  * is an opening paren/bracket/brace, the matching closing char is suffixed. */
 349 int get_default_nno_list(struct name_num_obj *nno, char *to_buf, int to_buf_len, char dup_markup)
 350 {
 351         struct name_num_item *nni;
 352         int len = 0, cnt = 0;
 353         char pre_char = '\0', post_char = '\0';
 354
 355         init_nno_saw(nno, 0);
 356
 357         for (nni = nno->list, len = 0; nni->name; nni++) {
 358                 if (nni->main_name) {
 359                         if (!dup_markup)
 360                                 continue;
 361                         pre_char = dup_markup;
 362                         switch (pre_char) {
 363                         case '(': post_char = ')'; break;
 364                         case '[': post_char = ']'; break;
 365                         case '{': post_char = '}'; break;
 366                         default: break;
 367                         }
 368                 }
 369                 if (len)
 370                         to_buf[len++]= ' ';
 371                 if (pre_char) {
 372                         to_buf[len++]= pre_char;
 373                         pre_char = '\0';
 374                 }
 375                 len += strlcpy(to_buf+len, nni->name, to_buf_len - len);
 376                 if (len >= to_buf_len - 3)
 377                         exit_cleanup(RERR_UNSUPPORTED); /* IMPOSSIBLE... */
 378                 if (post_char) {
 379                         to_buf[len++]= post_char;
 380                         post_char = '\0';
 381                 }
 382                 nno->saw[nni->num] = ++cnt;
 383         }
 384
 385         return len;
 386 }
 387
 388 static void send_negotiate_str(int f_out, struct name_num_obj *nno, const char *env_name)
 389 {
 390         char tmpbuf[MAX_NSTR_STRLEN];
 391         const char *list_str = getenv(env_name);
 392         int len, fail_if_empty = list_str && strstr(list_str, "FAIL");
 393
 394         if (!do_negotiated_strings) {
 395                 if (!am_server && fail_if_empty) {
 396                         rprintf(FERROR, "Remote rsync is too old for %s negotation\n", nno->type);
 397                         exit_cleanup(RERR_UNSUPPORTED);
 398                 }
 399                 return;
 400         }
 401
 402         if (list_str && *list_str && (!am_server || local_server)) {
 403                 init_nno_saw(nno, 0);
 404                 len = parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 405                 if (fail_if_empty && !len)
 406                         len = strlcpy(tmpbuf, "FAIL", MAX_NSTR_STRLEN);
 407                 list_str = tmpbuf;
 408         } else
 409                 list_str = NULL;
 410
 411         if (!list_str || !*list_str) {
 412                 len = get_default_nno_list(nno, tmpbuf, sizeof tmpbuf, '\0');
 413         }
 414
 415         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 416                 if (am_server)
 417                         rprintf(FINFO, "Server %s list (on server): %s\n", nno->type, tmpbuf);
 418                 else
 419                         rprintf(FINFO, "Client %s list (on client): %s\n", nno->type, tmpbuf);
 420         }
 421
 422         if (local_server) {
 423                 /* A local server doesn't bother to send/recv the strings, it just constructs
 424                  * and parses the same string on both sides. */
 425                 if (!read_batch)
 426                         recv_negotiate_str(-1, nno, tmpbuf, len);
 427         } else {
 428                 /* Each side sends their list of valid names to the other side and then both sides
 429                  * pick the first name in the client's list that is also in the server's list. */
 430                 write_vstring(f_out, tmpbuf, len);
 431         }
 432 }
 433
 434 static void negotiate_the_strings(int f_in, int f_out)
 435 {
 436         /* We send all the negotiation strings before we start to read them to help avoid a slow startup. */
 437
 438         if (!checksum_choice)
 439                 send_negotiate_str(f_out, &valid_checksums, "RSYNC_CHECKSUM_LIST");
 440
 441         if (do_compression && !compress_choice)
 442                 send_negotiate_str(f_out, &valid_compressions, "RSYNC_COMPRESS_LIST");
 443
 444         if (valid_checksums.saw) {
 445                 char tmpbuf[MAX_NSTR_STRLEN];
 446                 recv_negotiate_str(f_in, &valid_checksums, tmpbuf, -1);
 447         }
 448
 449         if (valid_compressions.saw) {
 450                 char tmpbuf[MAX_NSTR_STRLEN];
 451                 recv_negotiate_str(f_in, &valid_compressions, tmpbuf, -1);
 452         }
 453 }
 454
 455 void setup_protocol(int f_out,int f_in)
 456 {
 457         assert(file_extra_cnt == 0);
 458         assert(EXTRA64_CNT == 2 || EXTRA64_CNT == 1);
 459
 460         /* All int64 values must be set first so that they are guaranteed to be
 461          * aligned for direct int64-pointer memory access. */
 462         if (preserve_atimes)
 463                 atimes_ndx = (file_extra_cnt += EXTRA64_CNT);
 464         if (am_sender) /* This is most likely in the in64 union as well. */
 465                 pathname_ndx = (file_extra_cnt += PTR_EXTRA_CNT);
 466         else
 467                 depth_ndx = ++file_extra_cnt;
 468         if (preserve_uid)
 469                 uid_ndx = ++file_extra_cnt;
 470         if (preserve_gid)
 471                 gid_ndx = ++file_extra_cnt;
 472         if (preserve_acls && !am_sender)
 473                 acls_ndx = ++file_extra_cnt;
 474         if (preserve_xattrs)
 475                 xattrs_ndx = ++file_extra_cnt;
 476
 477         if (am_server)
 478                 set_allow_inc_recurse();
 479
 480         if (remote_protocol == 0) {
 481                 if (am_server && !local_server)
 482                         check_sub_protocol();
 483                 if (!read_batch)
 484                         write_int(f_out, protocol_version);
 485                 remote_protocol = read_int(f_in);
 486                 if (protocol_version > remote_protocol)
 487                         protocol_version = remote_protocol;
 488         }
 489         if (read_batch && remote_protocol > protocol_version) {
 490                 rprintf(FERROR, "The protocol version in the batch file is too new (%d > %d).\n",
 491                         remote_protocol, protocol_version);
 492                 exit_cleanup(RERR_PROTOCOL);
 493         }
 494
 495         if (DEBUG_GTE(PROTO, 1)) {
 496                 rprintf(FINFO, "(%s) Protocol versions: remote=%d, negotiated=%d\n",
 497                         am_server? "Server" : "Client", remote_protocol, protocol_version);
 498         }
 499         if (remote_protocol < MIN_PROTOCOL_VERSION
 500          || remote_protocol > MAX_PROTOCOL_VERSION) {
 501                 rprintf(FERROR,"protocol version mismatch -- is your shell clean?\n");
 502                 rprintf(FERROR,"(see the rsync man page for an explanation)\n");
 503                 exit_cleanup(RERR_PROTOCOL);
 504         }
 505         if (remote_protocol < OLD_PROTOCOL_VERSION) {
 506                 rprintf(FINFO,"%s is very old version of rsync, upgrade recommended.\n",
 507                         am_server? "Client" : "Server");
 508         }
 509         if (protocol_version < MIN_PROTOCOL_VERSION) {
 510                 rprintf(FERROR, "--protocol must be at least %d on the %s.\n",
 511                         MIN_PROTOCOL_VERSION, am_server? "Server" : "Client");
 512                 exit_cleanup(RERR_PROTOCOL);
 513         }
 514         if (protocol_version > PROTOCOL_VERSION) {
 515                 rprintf(FERROR, "--protocol must be no more than %d on the %s.\n",
 516                         PROTOCOL_VERSION, am_server? "Server" : "Client");
 517                 exit_cleanup(RERR_PROTOCOL);
 518         }
 519         if (read_batch)
 520                 check_batch_flags();
 521
 522 #ifndef SUPPORT_PREALLOCATION
 523         if (preallocate_files && !am_sender) {
 524                 rprintf(FERROR, "preallocation is not supported on this %s\n",
 525                         am_server ? "Server" : "Client");
 526                 exit_cleanup(RERR_SYNTAX);
 527         }
 528 #endif
 529
 530         if (protocol_version < 30) {
 531                 if (append_mode == 1)
 532                         append_mode = 2;
 533                 if (preserve_acls && !local_server) {
 534                         rprintf(FERROR,
 535                             "--acls requires protocol 30 or higher"
 536                             " (negotiated %d).\n",
 537                             protocol_version);
 538                         exit_cleanup(RERR_PROTOCOL);
 539                 }
 540                 if (preserve_xattrs && !local_server) {
 541                         rprintf(FERROR,
 542                             "--xattrs requires protocol 30 or higher"
 543                             " (negotiated %d).\n",
 544                             protocol_version);
 545                         exit_cleanup(RERR_PROTOCOL);
 546                 }
 547         }
 548
 549         if (delete_mode && !(delete_before+delete_during+delete_after)) {
 550                 if (protocol_version < 30)
 551                         delete_before = 1;
 552                 else
 553                         delete_during = 1;
 554         }
 555
 556         if (protocol_version < 29) {
 557                 if (fuzzy_basis) {
 558                         rprintf(FERROR,
 559                             "--fuzzy requires protocol 29 or higher"
 560                             " (negotiated %d).\n",
 561                             protocol_version);
 562                         exit_cleanup(RERR_PROTOCOL);
 563                 }
 564
 565                 if (basis_dir_cnt && inplace) {
 566                         rprintf(FERROR,
 567                             "%s with --inplace requires protocol 29 or higher"
 568                             " (negotiated %d).\n",
 569                             dest_option, protocol_version);
 570                         exit_cleanup(RERR_PROTOCOL);
 571                 }
 572
 573                 if (basis_dir_cnt > 1) {
 574                         rprintf(FERROR,
 575                             "Using more than one %s option requires protocol"
 576                             " 29 or higher (negotiated %d).\n",
 577                             dest_option, protocol_version);
 578                         exit_cleanup(RERR_PROTOCOL);
 579                 }
 580
 581                 if (prune_empty_dirs) {
 582                         rprintf(FERROR,
 583                             "--prune-empty-dirs requires protocol 29 or higher"
 584                             " (negotiated %d).\n",
 585                             protocol_version);
 586                         exit_cleanup(RERR_PROTOCOL);
 587                 }
 588         } else if (protocol_version >= 30) {
 589                 if (am_server) {
 590                         compat_flags = allow_inc_recurse ? CF_INC_RECURSE : 0;
 591 #ifdef CAN_SET_SYMLINK_TIMES
 592                         compat_flags |= CF_SYMLINK_TIMES;
 593 #endif
 594 #ifdef ICONV_OPTION
 595                         compat_flags |= CF_SYMLINK_ICONV;
 596 #endif
 597                         if (local_server || strchr(client_info, 'f') != NULL)
 598                                 compat_flags |= CF_SAFE_FLIST;
 599                         if (local_server || strchr(client_info, 'x') != NULL)
 600                                 compat_flags |= CF_AVOID_XATTR_OPTIM;
 601                         if (local_server || strchr(client_info, 'C') != NULL)
 602                                 compat_flags |= CF_CHKSUM_SEED_FIX;
 603                         if (local_server || strchr(client_info, 'I') != NULL)
 604                                 compat_flags |= CF_INPLACE_PARTIAL_DIR;
 605                         if (local_server || strchr(client_info, 'v') != NULL) {
 606                                 if (!write_batch || protocol_version >= 30) {
 607                                         do_negotiated_strings = 1;
 608                                         compat_flags |= CF_VARINT_FLIST_FLAGS;
 609                                 }
 610                         }
 611                         if (strchr(client_info, 'V') != NULL) { /* Support a pre-release 'V' that got superseded */
 612                                 if (!write_batch)
 613                                         compat_flags |= CF_VARINT_FLIST_FLAGS;
 614                                 write_byte(f_out, compat_flags);
 615                         } else
 616                                 write_varint(f_out, compat_flags);
 617                 } else { /* read_varint() is compatible with the older write_byte() when the 0x80 bit isn't on. */
 618                         compat_flags = read_varint(f_in);
 619                         if  (compat_flags & CF_VARINT_FLIST_FLAGS)
 620                                 do_negotiated_strings = 1;
 621                 }
 622                 /* The inc_recurse var MUST be set to 0 or 1. */
 623                 inc_recurse = compat_flags & CF_INC_RECURSE ? 1 : 0;
 624                 want_xattr_optim = protocol_version >= 31 && !(compat_flags & CF_AVOID_XATTR_OPTIM);
 625                 proper_seed_order = compat_flags & CF_CHKSUM_SEED_FIX ? 1 : 0;
 626                 xfer_flags_as_varint = compat_flags & CF_VARINT_FLIST_FLAGS ? 1 : 0;
 627                 if (am_sender) {
 628                         receiver_symlink_times = am_server
 629                             ? strchr(client_info, 'L') != NULL
 630                             : !!(compat_flags & CF_SYMLINK_TIMES);
 631                 }
 632 #ifdef CAN_SET_SYMLINK_TIMES
 633                 else
 634                         receiver_symlink_times = 1;
 635 #endif
 636 #ifdef ICONV_OPTION
 637                 sender_symlink_iconv = iconv_opt && (am_server
 638                     ? local_server || strchr(client_info, 's') != NULL
 639                     : !!(compat_flags & CF_SYMLINK_ICONV));
 640 #endif
 641                 if (inc_recurse && !allow_inc_recurse) {
 642                         /* This should only be able to happen in a batch. */
 643                         fprintf(stderr,
 644                             "Incompatible options specified for inc-recursive %s.\n",
 645                             read_batch ? "batch file" : "connection");
 646                         exit_cleanup(RERR_SYNTAX);
 647                 }
 648                 use_safe_inc_flist = (compat_flags & CF_SAFE_FLIST) || protocol_version >= 31;
 649                 need_messages_from_generator = 1;
 650                 if (compat_flags & CF_INPLACE_PARTIAL_DIR)
 651                         inplace_partial = 1;
 652 #ifdef CAN_SET_SYMLINK_TIMES
 653         } else if (!am_sender) {
 654                 receiver_symlink_times = 1;
 655 #endif
 656         }
 657
 658         if (need_unsorted_flist && (!am_sender || inc_recurse))
 659                 unsort_ndx = ++file_extra_cnt;
 660
 661         if (partial_dir && *partial_dir != '/' && (!am_server || local_server)) {
 662                 int rflags = FILTRULE_NO_PREFIXES | FILTRULE_DIRECTORY;
 663                 if (!am_sender || protocol_version >= 30)
 664                         rflags |= FILTRULE_PERISHABLE;
 665                 parse_filter_str(&filter_list, partial_dir, rule_template(rflags), 0);
 666         }
 667
 668
 669 #ifdef ICONV_OPTION
 670         if (protect_args && files_from) {
 671                 if (am_sender)
 672                         filesfrom_convert = filesfrom_host && ic_send != (iconv_t)-1;
 673                 else
 674                         filesfrom_convert = !filesfrom_host && ic_recv != (iconv_t)-1;
 675         }
 676 #endif
 677
 678         negotiate_the_strings(f_in, f_out);
 679
 680         if (am_server) {
 681                 if (!checksum_seed)
 682                         checksum_seed = time(NULL) ^ (getpid() << 6);
 683                 write_int(f_out, checksum_seed);
 684         } else {
 685                 checksum_seed = read_int(f_in);
 686         }
 687
 688         init_flist();
 689 }
 690
 691 void maybe_write_negotiated_strings(int batch_fd)
 692 {
 693         if (valid_checksums.negotiated_name)
 694                 write_vstring(batch_fd, valid_checksums.negotiated_name, strlen(valid_checksums.negotiated_name));
 695
 696         if (valid_compressions.negotiated_name)
 697                 write_vstring(batch_fd, valid_compressions.negotiated_name, strlen(valid_compressions.negotiated_name));
 698 }