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 *files_from;
  55 extern char *filesfrom_host;
  56 extern const char *checksum_choice;
  57 extern const char *compress_choice;
  58 extern filter_rule_list filter_list;
  59 extern int need_unsorted_flist;
  60 #ifdef ICONV_OPTION
  61 extern iconv_t ic_send, ic_recv;
  62 extern char *iconv_opt;
  63 #endif
  64 extern struct name_num_obj valid_checksums;
  65
  66 int remote_protocol = 0;
  67 int file_extra_cnt = 0; /* count of file-list extras that everyone gets */
  68 int inc_recurse = 0;
  69 int compat_flags = 0;
  70 int use_safe_inc_flist = 0;
  71 int want_xattr_optim = 0;
  72 int proper_seed_order = 0;
  73 int inplace_partial = 0;
  74 int do_negotiated_strings = 0;
  75
  76 /* These index values are for the file-list's extra-attribute array. */
  77 int pathname_ndx, depth_ndx, atimes_ndx, uid_ndx, gid_ndx, acls_ndx, xattrs_ndx, unsort_ndx;
  78
  79 int receiver_symlink_times = 0; /* receiver can set the time on a symlink */
  80 int sender_symlink_iconv = 0;   /* sender should convert symlink content */
  81
  82 #ifdef ICONV_OPTION
  83 int filesfrom_convert = 0;
  84 #endif
  85
  86 #define MAX_NSTR_STRLEN 256
  87
  88 struct name_num_obj valid_compressions = {
  89         "compress", NULL, NULL, 0, 0, {
  90 #ifdef SUPPORT_ZSTD
  91                 { CPRES_ZSTD, "zstd", NULL },
  92 #endif
  93 #ifdef SUPPORT_LZ4
  94                 { CPRES_LZ4, "lz4", NULL },
  95 #endif
  96                 { CPRES_ZLIBX, "zlibx", NULL },
  97                 { CPRES_ZLIB, "zlib", NULL },
  98                 { CPRES_NONE, "none", NULL },
  99                 { 0, NULL, NULL }
 100         }
 101 };
 102
 103 #define CF_INC_RECURSE   (1<<0)
 104 #define CF_SYMLINK_TIMES (1<<1)
 105 #define CF_SYMLINK_ICONV (1<<2)
 106 #define CF_SAFE_FLIST    (1<<3)
 107 #define CF_AVOID_XATTR_OPTIM (1<<4)
 108 #define CF_CHKSUM_SEED_FIX (1<<5)
 109 #define CF_INPLACE_PARTIAL_DIR (1<<6)
 110 #define CF_VARINT_FLIST_FLAGS (1<<7)
 111
 112 static const char *client_info;
 113
 114 /* The server makes sure that if either side only supports a pre-release
 115  * version of a protocol, that both sides must speak a compatible version
 116  * of that protocol for it to be advertised as available. */
 117 static void check_sub_protocol(void)
 118 {
 119         char *dot;
 120         int their_protocol, their_sub;
 121 #if SUBPROTOCOL_VERSION != 0
 122         int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
 123 #else
 124         int our_sub = 0;
 125 #endif
 126
 127         /* client_info starts with VER.SUB string if client is a pre-release. */
 128         if (!(their_protocol = atoi(client_info))
 129          || !(dot = strchr(client_info, '.'))
 130          || !(their_sub = atoi(dot+1))) {
 131 #if SUBPROTOCOL_VERSION != 0
 132                 if (our_sub)
 133                         protocol_version--;
 134 #endif
 135                 return;
 136         }
 137
 138         if (their_protocol < protocol_version) {
 139                 if (their_sub)
 140                         protocol_version = their_protocol - 1;
 141                 return;
 142         }
 143
 144         if (their_protocol > protocol_version)
 145                 their_sub = 0; /* 0 == final version of older protocol */
 146         if (their_sub != our_sub)
 147                 protocol_version--;
 148 }
 149
 150 void set_allow_inc_recurse(void)
 151 {
 152         client_info = shell_cmd ? shell_cmd : "";
 153
 154         if (!recurse || use_qsort)
 155                 allow_inc_recurse = 0;
 156         else if (!am_sender
 157          && (delete_before || delete_after
 158           || delay_updates || prune_empty_dirs))
 159                 allow_inc_recurse = 0;
 160         else if (am_server && !local_server
 161          && (strchr(client_info, 'i') == NULL))
 162                 allow_inc_recurse = 0;
 163 }
 164
 165 void parse_compress_choice(int final_call)
 166 {
 167         if (valid_compressions.negotiated_name)
 168                 do_compression = valid_compressions.negotiated_num;
 169         else if (compress_choice) {
 170                 struct name_num_item *nni = get_nni_by_name(&valid_compressions, compress_choice, -1);
 171                 if (!nni) {
 172                         rprintf(FERROR, "unknown compress name: %s\n", compress_choice);
 173                         exit_cleanup(RERR_UNSUPPORTED);
 174                 }
 175                 do_compression = nni->num;
 176         } else if (do_compression)
 177                 do_compression = CPRES_ZLIB;
 178         else
 179                 do_compression = CPRES_NONE;
 180
 181         if (do_compression != CPRES_NONE && final_call)
 182                 init_compression_level(); /* There's a chance this might turn compression off! */
 183
 184         if (do_compression == CPRES_NONE)
 185                 compress_choice = NULL;
 186
 187         /* Snag the compression name for both write_batch's option output & the following debug output. */
 188         if (valid_compressions.negotiated_name)
 189                 compress_choice = valid_compressions.negotiated_name;
 190         else if (compress_choice == NULL) {
 191                 struct name_num_item *nni = get_nni_by_num(&valid_compressions, do_compression);
 192                 compress_choice = nni ? nni->name : "UNKNOWN";
 193         }
 194
 195         if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)
 196          && (do_compression != CPRES_NONE || do_compression_level != CLVL_NOT_SPECIFIED)) {
 197                 rprintf(FINFO, "%s%s compress: %s (level %d)\n",
 198                         am_server ? "Server" : "Client",
 199                         valid_compressions.negotiated_name ? " negotiated" : "",
 200                         compress_choice, do_compression_level);
 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 delim = '\0', post_delim;
 354
 355         switch (dup_markup) {
 356         case '(': post_delim = ')'; break;
 357         case '[': post_delim = ']'; break;
 358         case '{': post_delim = '}'; break;
 359         default: post_delim = '\0'; break;
 360         }
 361
 362         init_nno_saw(nno, 0);
 363
 364         for (nni = nno->list, len = 0; nni->name; nni++) {
 365                 if (nni->main_name) {
 366                         if (!dup_markup)
 367                                 continue;
 368                         delim = dup_markup;
 369                 }
 370                 if (len)
 371                         to_buf[len++]= ' ';
 372                 if (delim) {
 373                         to_buf[len++]= delim;
 374                         delim = post_delim;
 375                 }
 376                 len += strlcpy(to_buf+len, nni->name, to_buf_len - len);
 377                 if (len >= to_buf_len - 3)
 378                         exit_cleanup(RERR_UNSUPPORTED); /* IMPOSSIBLE... */
 379                 if (delim) {
 380                         to_buf[len++]= delim;
 381                         delim = '\0';
 382                 }
 383                 nno->saw[nni->num] = ++cnt;
 384         }
 385
 386         return len;
 387 }
 388
 389 static void send_negotiate_str(int f_out, struct name_num_obj *nno, const char *env_name)
 390 {
 391         char tmpbuf[MAX_NSTR_STRLEN];
 392         const char *list_str = getenv(env_name);
 393         int len, fail_if_empty = list_str && strstr(list_str, "FAIL");
 394
 395         if (!do_negotiated_strings) {
 396                 if (!am_server && fail_if_empty) {
 397                         rprintf(FERROR, "Remote rsync is too old for %s negotiation\n", nno->type);
 398                         exit_cleanup(RERR_UNSUPPORTED);
 399                 }
 400                 return;
 401         }
 402
 403         if (list_str && *list_str && (!am_server || local_server)) {
 404                 init_nno_saw(nno, 0);
 405                 len = parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 406                 if (fail_if_empty && !len)
 407                         len = strlcpy(tmpbuf, "FAIL", MAX_NSTR_STRLEN);
 408                 list_str = tmpbuf;
 409         } else
 410                 list_str = NULL;
 411
 412         if (!list_str || !*list_str)
 413                 len = get_default_nno_list(nno, tmpbuf, MAX_NSTR_STRLEN, '\0');
 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                 recv_negotiate_str(-1, nno, tmpbuf, len);
 426         } else {
 427                 /* Each side sends their list of valid names to the other side and then both sides
 428                  * pick the first name in the client's list that is also in the server's list. */
 429                 write_vstring(f_out, tmpbuf, len);
 430         }
 431 }
 432
 433 static void negotiate_the_strings(int f_in, int f_out)
 434 {
 435         /* We send all the negotiation strings before we start to read them to help avoid a slow startup. */
 436
 437         if (!checksum_choice)
 438                 send_negotiate_str(f_out, &valid_checksums, "RSYNC_CHECKSUM_LIST");
 439
 440         if (do_compression && !compress_choice)
 441                 send_negotiate_str(f_out, &valid_compressions, "RSYNC_COMPRESS_LIST");
 442
 443         if (valid_checksums.saw) {
 444                 char tmpbuf[MAX_NSTR_STRLEN];
 445                 recv_negotiate_str(f_in, &valid_checksums, tmpbuf, -1);
 446         }
 447
 448         if (valid_compressions.saw) {
 449                 char tmpbuf[MAX_NSTR_STRLEN];
 450                 recv_negotiate_str(f_in, &valid_compressions, tmpbuf, -1);
 451         }
 452 }
 453
 454 void setup_protocol(int f_out,int f_in)
 455 {
 456         assert(file_extra_cnt == 0);
 457         assert(EXTRA64_CNT == 2 || EXTRA64_CNT == 1);
 458
 459         /* All int64 values must be set first so that they are guaranteed to be
 460          * aligned for direct int64-pointer memory access. */
 461         if (preserve_atimes)
 462                 atimes_ndx = (file_extra_cnt += EXTRA64_CNT);
 463         if (am_sender) /* This is most likely in the in64 union as well. */
 464                 pathname_ndx = (file_extra_cnt += PTR_EXTRA_CNT);
 465         else
 466                 depth_ndx = ++file_extra_cnt;
 467         if (preserve_uid)
 468                 uid_ndx = ++file_extra_cnt;
 469         if (preserve_gid)
 470                 gid_ndx = ++file_extra_cnt;
 471         if (preserve_acls && !am_sender)
 472                 acls_ndx = ++file_extra_cnt;
 473         if (preserve_xattrs)
 474                 xattrs_ndx = ++file_extra_cnt;
 475
 476         if (am_server)
 477                 set_allow_inc_recurse();
 478
 479         if (remote_protocol == 0) {
 480                 if (am_server && !local_server)
 481                         check_sub_protocol();
 482                 if (!read_batch)
 483                         write_int(f_out, protocol_version);
 484                 remote_protocol = read_int(f_in);
 485                 if (protocol_version > remote_protocol)
 486                         protocol_version = remote_protocol;
 487         }
 488         if (read_batch && remote_protocol > protocol_version) {
 489                 rprintf(FERROR, "The protocol version in the batch file is too new (%d > %d).\n",
 490                         remote_protocol, protocol_version);
 491                 exit_cleanup(RERR_PROTOCOL);
 492         }
 493
 494         if (DEBUG_GTE(PROTO, 1)) {
 495                 rprintf(FINFO, "(%s) Protocol versions: remote=%d, negotiated=%d\n",
 496                         am_server? "Server" : "Client", remote_protocol, protocol_version);
 497         }
 498         if (remote_protocol < MIN_PROTOCOL_VERSION
 499          || remote_protocol > MAX_PROTOCOL_VERSION) {
 500                 rprintf(FERROR,"protocol version mismatch -- is your shell clean?\n");
 501                 rprintf(FERROR,"(see the rsync man page for an explanation)\n");
 502                 exit_cleanup(RERR_PROTOCOL);
 503         }
 504         if (remote_protocol < OLD_PROTOCOL_VERSION) {
 505                 rprintf(FINFO,"%s is very old version of rsync, upgrade recommended.\n",
 506                         am_server? "Client" : "Server");
 507         }
 508         if (protocol_version < MIN_PROTOCOL_VERSION) {
 509                 rprintf(FERROR, "--protocol must be at least %d on the %s.\n",
 510                         MIN_PROTOCOL_VERSION, am_server? "Server" : "Client");
 511                 exit_cleanup(RERR_PROTOCOL);
 512         }
 513         if (protocol_version > PROTOCOL_VERSION) {
 514                 rprintf(FERROR, "--protocol must be no more than %d on the %s.\n",
 515                         PROTOCOL_VERSION, am_server? "Server" : "Client");
 516                 exit_cleanup(RERR_PROTOCOL);
 517         }
 518         if (read_batch)
 519                 check_batch_flags();
 520
 521 #ifndef SUPPORT_PREALLOCATION
 522         if (preallocate_files && !am_sender) {
 523                 rprintf(FERROR, "preallocation is not supported on this %s\n",
 524                         am_server ? "Server" : "Client");
 525                 exit_cleanup(RERR_SYNTAX);
 526         }
 527 #endif
 528
 529         if (protocol_version < 30) {
 530                 if (append_mode == 1)
 531                         append_mode = 2;
 532                 if (preserve_acls && !local_server) {
 533                         rprintf(FERROR,
 534                                 "--acls requires protocol 30 or higher"
 535                                 " (negotiated %d).\n",
 536                                 protocol_version);
 537                         exit_cleanup(RERR_PROTOCOL);
 538                 }
 539                 if (preserve_xattrs && !local_server) {
 540                         rprintf(FERROR,
 541                                 "--xattrs requires protocol 30 or higher"
 542                                 " (negotiated %d).\n",
 543                                 protocol_version);
 544                         exit_cleanup(RERR_PROTOCOL);
 545                 }
 546         }
 547
 548         if (delete_mode && !(delete_before+delete_during+delete_after)) {
 549                 if (protocol_version < 30)
 550                         delete_before = 1;
 551                 else
 552                         delete_during = 1;
 553         }
 554
 555         if (protocol_version < 29) {
 556                 if (fuzzy_basis) {
 557                         rprintf(FERROR,
 558                                 "--fuzzy requires protocol 29 or higher"
 559                                 " (negotiated %d).\n",
 560                                 protocol_version);
 561                         exit_cleanup(RERR_PROTOCOL);
 562                 }
 563
 564                 if (basis_dir_cnt && inplace) {
 565                         rprintf(FERROR,
 566                                 "%s with --inplace requires protocol 29 or higher"
 567                                 " (negotiated %d).\n",
 568                                 alt_dest_opt(0), protocol_version);
 569                         exit_cleanup(RERR_PROTOCOL);
 570                 }
 571
 572                 if (basis_dir_cnt > 1) {
 573                         rprintf(FERROR,
 574                                 "Using more than one %s option requires protocol"
 575                                 " 29 or higher (negotiated %d).\n",
 576                                 alt_dest_opt(0), protocol_version);
 577                         exit_cleanup(RERR_PROTOCOL);
 578                 }
 579
 580                 if (prune_empty_dirs) {
 581                         rprintf(FERROR,
 582                                 "--prune-empty-dirs requires protocol 29 or higher"
 583                                 " (negotiated %d).\n",
 584                                 protocol_version);
 585                         exit_cleanup(RERR_PROTOCOL);
 586                 }
 587         } else if (protocol_version >= 30) {
 588                 if (am_server) {
 589                         compat_flags = allow_inc_recurse ? CF_INC_RECURSE : 0;
 590 #ifdef CAN_SET_SYMLINK_TIMES
 591                         compat_flags |= CF_SYMLINK_TIMES;
 592 #endif
 593 #ifdef ICONV_OPTION
 594                         compat_flags |= CF_SYMLINK_ICONV;
 595 #endif
 596                         if (local_server || strchr(client_info, 'f') != NULL)
 597                                 compat_flags |= CF_SAFE_FLIST;
 598                         if (local_server || strchr(client_info, 'x') != NULL)
 599                                 compat_flags |= CF_AVOID_XATTR_OPTIM;
 600                         if (local_server || strchr(client_info, 'C') != NULL)
 601                                 compat_flags |= CF_CHKSUM_SEED_FIX;
 602                         if (local_server || strchr(client_info, 'I') != NULL)
 603                                 compat_flags |= CF_INPLACE_PARTIAL_DIR;
 604                         if (local_server || strchr(client_info, 'v') != NULL) {
 605                                 if (!write_batch || protocol_version >= 30) {
 606                                         do_negotiated_strings = 1;
 607                                         compat_flags |= CF_VARINT_FLIST_FLAGS;
 608                                 }
 609                         }
 610                         if (strchr(client_info, 'V') != NULL) { /* Support a pre-release 'V' that got superseded */
 611                                 if (!write_batch)
 612                                         compat_flags |= CF_VARINT_FLIST_FLAGS;
 613                                 write_byte(f_out, compat_flags);
 614                         } else
 615                                 write_varint(f_out, compat_flags);
 616                 } else { /* read_varint() is compatible with the older write_byte() when the 0x80 bit isn't on. */
 617                         compat_flags = read_varint(f_in);
 618                         if  (compat_flags & CF_VARINT_FLIST_FLAGS)
 619                                 do_negotiated_strings = 1;
 620                 }
 621                 /* The inc_recurse var MUST be set to 0 or 1. */
 622                 inc_recurse = compat_flags & CF_INC_RECURSE ? 1 : 0;
 623                 want_xattr_optim = protocol_version >= 31 && !(compat_flags & CF_AVOID_XATTR_OPTIM);
 624                 proper_seed_order = compat_flags & CF_CHKSUM_SEED_FIX ? 1 : 0;
 625                 xfer_flags_as_varint = compat_flags & CF_VARINT_FLIST_FLAGS ? 1 : 0;
 626                 if (am_sender) {
 627                         receiver_symlink_times = am_server
 628                             ? strchr(client_info, 'L') != NULL
 629                             : !!(compat_flags & CF_SYMLINK_TIMES);
 630                 }
 631 #ifdef CAN_SET_SYMLINK_TIMES
 632                 else
 633                         receiver_symlink_times = 1;
 634 #endif
 635 #ifdef ICONV_OPTION
 636                 sender_symlink_iconv = iconv_opt && (am_server
 637                     ? local_server || strchr(client_info, 's') != NULL
 638                     : !!(compat_flags & CF_SYMLINK_ICONV));
 639 #endif
 640                 if (inc_recurse && !allow_inc_recurse) {
 641                         /* This should only be able to happen in a batch. */
 642                         fprintf(stderr,
 643                                 "Incompatible options specified for inc-recursive %s.\n",
 644                                 read_batch ? "batch file" : "connection");
 645                         exit_cleanup(RERR_SYNTAX);
 646                 }
 647                 use_safe_inc_flist = (compat_flags & CF_SAFE_FLIST) || protocol_version >= 31;
 648                 need_messages_from_generator = 1;
 649                 if (compat_flags & CF_INPLACE_PARTIAL_DIR)
 650                         inplace_partial = 1;
 651 #ifdef CAN_SET_SYMLINK_TIMES
 652         } else if (!am_sender) {
 653                 receiver_symlink_times = 1;
 654 #endif
 655         }
 656
 657         if (need_unsorted_flist && (!am_sender || inc_recurse))
 658                 unsort_ndx = ++file_extra_cnt;
 659
 660         if (partial_dir && *partial_dir != '/' && (!am_server || local_server)) {
 661                 int rflags = FILTRULE_NO_PREFIXES | FILTRULE_DIRECTORY;
 662                 if (!am_sender || protocol_version >= 30)
 663                         rflags |= FILTRULE_PERISHABLE;
 664                 parse_filter_str(&filter_list, partial_dir, rule_template(rflags), 0);
 665         }
 666
 667
 668 #ifdef ICONV_OPTION
 669         if (protect_args && files_from) {
 670                 if (am_sender)
 671                         filesfrom_convert = filesfrom_host && ic_send != (iconv_t)-1;
 672                 else
 673                         filesfrom_convert = !filesfrom_host && ic_recv != (iconv_t)-1;
 674         }
 675 #endif
 676
 677         negotiate_the_strings(f_in, f_out);
 678
 679         if (am_server) {
 680                 if (!checksum_seed)
 681                         checksum_seed = time(NULL) ^ (getpid() << 6);
 682                 write_int(f_out, checksum_seed);
 683         } else {
 684                 checksum_seed = read_int(f_in);
 685         }
 686
 687         parse_checksum_choice(1); /* Sets checksum_type & xfersum_type */
 688         parse_compress_choice(1); /* Sets do_compression */
 689
 690         if (write_batch && !am_server)
 691                 write_batch_shell_file();
 692
 693         init_flist();
 694 }