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 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
  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 #ifdef SUPPORT_ZSTD
  92                 { CPRES_ZSTD, "zstd", NULL },
  93 #endif
  94 #ifdef SUPPORT_LZ4
  95                 { CPRES_LZ4, "lz4", NULL },
  96 #endif
  97                 { CPRES_ZLIBX, "zlibx", NULL },
  98                 { CPRES_ZLIB, "zlib", NULL },
  99                 { CPRES_NONE, "none", NULL },
 100                 { 0, NULL, NULL }
 101         }
 102 };
 103
 104 #define CF_INC_RECURSE   (1<<0)
 105 #define CF_SYMLINK_TIMES (1<<1)
 106 #define CF_SYMLINK_ICONV (1<<2)
 107 #define CF_SAFE_FLIST    (1<<3)
 108 #define CF_AVOID_XATTR_OPTIM (1<<4)
 109 #define CF_CHKSUM_SEED_FIX (1<<5)
 110 #define CF_INPLACE_PARTIAL_DIR (1<<6)
 111 #define CF_VARINT_FLIST_FLAGS (1<<7)
 112
 113 static const char *client_info;
 114
 115 /* The server makes sure that if either side only supports a pre-release
 116  * version of a protocol, that both sides must speak a compatible version
 117  * of that protocol for it to be advertised as available. */
 118 static void check_sub_protocol(void)
 119 {
 120         char *dot;
 121         int their_protocol, their_sub;
 122 #if SUBPROTOCOL_VERSION != 0
 123         int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
 124 #else
 125         int our_sub = 0;
 126 #endif
 127
 128         /* client_info starts with VER.SUB string if client is a pre-release. */
 129         if (!(their_protocol = atoi(client_info))
 130          || !(dot = strchr(client_info, '.'))
 131          || !(their_sub = atoi(dot+1))) {
 132 #if SUBPROTOCOL_VERSION != 0
 133                 if (our_sub)
 134                         protocol_version--;
 135 #endif
 136                 return;
 137         }
 138
 139         if (their_protocol < protocol_version) {
 140                 if (their_sub)
 141                         protocol_version = their_protocol - 1;
 142                 return;
 143         }
 144
 145         if (their_protocol > protocol_version)
 146                 their_sub = 0; /* 0 == final version of older protocol */
 147         if (their_sub != our_sub)
 148                 protocol_version--;
 149 }
 150
 151 void set_allow_inc_recurse(void)
 152 {
 153         client_info = shell_cmd ? shell_cmd : "";
 154
 155         if (!recurse || use_qsort)
 156                 allow_inc_recurse = 0;
 157         else if (!am_sender
 158          && (delete_before || delete_after
 159           || delay_updates || prune_empty_dirs))
 160                 allow_inc_recurse = 0;
 161         else if (am_server && !local_server
 162          && (strchr(client_info, 'i') == NULL))
 163                 allow_inc_recurse = 0;
 164 }
 165
 166 void parse_compress_choice(int final_call)
 167 {
 168         if (valid_compressions.negotiated_name)
 169                 do_compression = valid_compressions.negotiated_num;
 170         else if (compress_choice) {
 171                 struct name_num_item *nni = get_nni_by_name(&valid_compressions, compress_choice, -1);
 172                 if (!nni) {
 173                         rprintf(FERROR, "unknown compress name: %s\n", compress_choice);
 174                         exit_cleanup(RERR_UNSUPPORTED);
 175                 }
 176                 do_compression = nni->num;
 177         } else if (do_compression)
 178                 do_compression = CPRES_ZLIB;
 179         else
 180                 do_compression = CPRES_NONE;
 181
 182         if (do_compression != CPRES_NONE && final_call)
 183                 init_compression_level(); /* There's a chance this might turn compression off! */
 184
 185         if (do_compression == CPRES_NONE)
 186                 compress_choice = NULL;
 187
 188         /* Snag the compression name for both write_batch's option output & the following debug output. */
 189         if (valid_compressions.negotiated_name)
 190                 compress_choice = valid_compressions.negotiated_name;
 191         else if (compress_choice == NULL) {
 192                 struct name_num_item *nni = get_nni_by_num(&valid_compressions, do_compression);
 193                 compress_choice = nni ? nni->name : "UNKNOWN";
 194         }
 195
 196         if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)
 197          && (do_compression != CPRES_NONE || do_compression_level != CLVL_NOT_SPECIFIED)) {
 198                 rprintf(FINFO, "%s%s compress: %s (level %d)\n",
 199                         am_server ? "Server" : "Client",
 200                         valid_compressions.negotiated_name ? " negotiated" : "",
 201                         compress_choice, do_compression_level);
 202         }
 203 }
 204
 205 struct name_num_item *get_nni_by_name(struct name_num_obj *nno, const char *name, int len)
 206 {
 207         struct name_num_item *nni;
 208
 209         if (len < 0)
 210                 len = strlen(name);
 211
 212         for (nni = nno->list; nni->name; nni++) {
 213                 if (strncasecmp(name, nni->name, len) == 0 && nni->name[len] == '\0')
 214                         return nni;
 215         }
 216
 217         return NULL;
 218 }
 219
 220 struct name_num_item *get_nni_by_num(struct name_num_obj *nno, int num)
 221 {
 222         struct name_num_item *nni;
 223
 224         for (nni = nno->list; nni->name; nni++) {
 225                 if (num == nni->num)
 226                         return nni;
 227         }
 228
 229         return NULL;
 230 }
 231
 232 static void init_nno_saw(struct name_num_obj *nno, int val)
 233 {
 234         struct name_num_item *nni;
 235         int cnt;
 236
 237         if (!nno->saw_len) {
 238                 for (nni = nno->list; nni->name; nni++) {
 239                         if (nni->num >= nno->saw_len)
 240                                 nno->saw_len = nni->num + 1;
 241                 }
 242         }
 243
 244         if (!nno->saw) {
 245                 if (!(nno->saw = new_array0(uchar, nno->saw_len)))
 246                         out_of_memory("init_nno_saw");
 247
 248                 /* We'll take this opportunity to make sure that the main_name values are set right. */
 249                 for (cnt = 1, nni = nno->list; nni->name; nni++, cnt++) {
 250                         if (nno->saw[nni->num])
 251                                 nni->main_name = nno->list[nno->saw[nni->num]-1].name;
 252                         else
 253                                 nno->saw[nni->num] = cnt;
 254                 }
 255         }
 256
 257         memset(nno->saw, val, nno->saw_len);
 258 }
 259
 260 /* Simplify the user-provided string so that it contains valid names without any duplicates.
 261  * It also sets the "saw" flags to a 1-relative count of which name was seen first. */
 262 static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf, int tobuf_len)
 263 {
 264         char *to = tobuf, *tok = NULL;
 265         int cnt = 0;
 266
 267         while (1) {
 268                 if (*from == ' ' || !*from) {
 269                         if (tok) {
 270                                 struct name_num_item *nni = get_nni_by_name(nno, tok, to - tok);
 271                                 if (nni && !nno->saw[nni->num]) {
 272                                         nno->saw[nni->num] = ++cnt;
 273                                         if (nni->main_name) {
 274                                                 to = tok + strlcpy(tok, nni->main_name, tobuf_len - (tok - tobuf));
 275                                                 if (to - tobuf >= tobuf_len) {
 276                                                         to = tok - 1;
 277                                                         break;
 278                                                 }
 279                                         }
 280                                 } else
 281                                         to = tok - (tok != tobuf);
 282                                 tok = NULL;
 283                         }
 284                         if (!*from++)
 285                                 break;
 286                         continue;
 287                 }
 288                 if (!tok) {
 289                         if (to != tobuf)
 290                                 *to++ = ' ';
 291                         tok = to;
 292                 }
 293                 if (to - tobuf >= tobuf_len - 1) {
 294                         to = tok - (tok != tobuf);
 295                         break;
 296                 }
 297                 *to++ = *from++;
 298         }
 299         *to = '\0';
 300
 301         return to - tobuf;
 302 }
 303
 304 static void recv_negotiate_str(int f_in, struct name_num_obj *nno, char *tmpbuf, int len)
 305 {
 306         struct name_num_item *ret = NULL;
 307
 308         if (len < 0)
 309                 len = read_vstring(f_in, tmpbuf, MAX_NSTR_STRLEN);
 310
 311         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 312                 if (am_server)
 313                         rprintf(FINFO, "Client %s list (on server): %s\n", nno->type, tmpbuf);
 314                 else
 315                         rprintf(FINFO, "Server %s list (on client): %s\n", nno->type, tmpbuf);
 316         }
 317
 318         if (len > 0) {
 319                 int best = nno->saw_len; /* We want best == 1 from the client list, so start with a big number. */
 320                 char *tok;
 321                 if (am_server)
 322                         init_nno_saw(nno, 1); /* Since we're parsing client names, anything we parse first is #1. */
 323                 for (tok = strtok(tmpbuf, " \t"); tok; tok = strtok(NULL, " \t")) {
 324                         struct name_num_item *nni = get_nni_by_name(nno, tok, -1);
 325                         if (!nni || !nno->saw[nni->num] || best <= nno->saw[nni->num])
 326                                 continue;
 327                         ret = nni;
 328                         best = nno->saw[nni->num];
 329                         if (best == 1)
 330                                 break;
 331                 }
 332                 if (ret) {
 333                         free(nno->saw);
 334                         nno->saw = NULL;
 335                         nno->negotiated_name = ret->main_name ? ret->main_name : ret->name;
 336                         nno->negotiated_num = ret->num;
 337                         return;
 338                 }
 339         }
 340
 341         if (!am_server)
 342                 rprintf(FERROR, "Failed to negotiate a common %s\n", nno->type);
 343         exit_cleanup(RERR_UNSUPPORTED);
 344 }
 345
 346 /* The saw buffer is initialized and used to store ordinal values from 1 to N
 347  * for the order of the args in the array.  If dup_markup == '\0', duplicates
 348  * are removed otherwise the char is prefixed to the duplicate term and, if it
 349  * is an opening paren/bracket/brace, the matching closing char is suffixed. */
 350 int get_default_nno_list(struct name_num_obj *nno, char *to_buf, int to_buf_len, char dup_markup)
 351 {
 352         struct name_num_item *nni;
 353         int len = 0, cnt = 0;
 354         char delim = '\0', post_delim;
 355
 356         switch (dup_markup) {
 357         case '(': post_delim = ')'; break;
 358         case '[': post_delim = ']'; break;
 359         case '{': post_delim = '}'; break;
 360         default: post_delim = '\0'; break;
 361         }
 362
 363         init_nno_saw(nno, 0);
 364
 365         for (nni = nno->list, len = 0; nni->name; nni++) {
 366                 if (nni->main_name) {
 367                         if (!dup_markup)
 368                                 continue;
 369                         delim = dup_markup;
 370                 }
 371                 if (len)
 372                         to_buf[len++]= ' ';
 373                 if (delim) {
 374                         to_buf[len++]= delim;
 375                         delim = post_delim;
 376                 }
 377                 len += strlcpy(to_buf+len, nni->name, to_buf_len - len);
 378                 if (len >= to_buf_len - 3)
 379                         exit_cleanup(RERR_UNSUPPORTED); /* IMPOSSIBLE... */
 380                 if (delim) {
 381                         to_buf[len++]= delim;
 382                         delim = '\0';
 383                 }
 384                 nno->saw[nni->num] = ++cnt;
 385         }
 386
 387         return len;
 388 }
 389
 390 static void send_negotiate_str(int f_out, struct name_num_obj *nno, const char *env_name)
 391 {
 392         char tmpbuf[MAX_NSTR_STRLEN];
 393         const char *list_str = getenv(env_name);
 394         int len, fail_if_empty = list_str && strstr(list_str, "FAIL");
 395
 396         if (!do_negotiated_strings) {
 397                 if (!am_server && fail_if_empty) {
 398                         rprintf(FERROR, "Remote rsync is too old for %s negotation\n", nno->type);
 399                         exit_cleanup(RERR_UNSUPPORTED);
 400                 }
 401                 return;
 402         }
 403
 404         if (list_str && *list_str && (!am_server || local_server)) {
 405                 init_nno_saw(nno, 0);
 406                 len = parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 407                 if (fail_if_empty && !len)
 408                         len = strlcpy(tmpbuf, "FAIL", MAX_NSTR_STRLEN);
 409                 list_str = tmpbuf;
 410         } else
 411                 list_str = NULL;
 412
 413         if (!list_str || !*list_str)
 414                 len = get_default_nno_list(nno, tmpbuf, MAX_NSTR_STRLEN, '\0');
 415
 416         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 417                 if (am_server)
 418                         rprintf(FINFO, "Server %s list (on server): %s\n", nno->type, tmpbuf);
 419                 else
 420                         rprintf(FINFO, "Client %s list (on client): %s\n", nno->type, tmpbuf);
 421         }
 422
 423         if (local_server) {
 424                 /* A local server doesn't bother to send/recv the strings, it just constructs
 425                  * and parses the same string on both sides. */
 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         parse_checksum_choice(1); /* Sets checksum_type & xfersum_type */
 689         parse_compress_choice(1); /* Sets do_compression */
 690
 691         if (write_batch && !am_server)
 692                 write_batch_shell_file();
 693
 694         init_flist();
 695 }