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) 2004-2022 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 #include "ifuncs.h"
  25
  26 extern int am_server;
  27 extern int am_sender;
  28 extern int local_server;
  29 extern int inplace;
  30 extern int recurse;
  31 extern int use_qsort;
  32 extern int allow_inc_recurse;
  33 extern int preallocate_files;
  34 extern int append_mode;
  35 extern int fuzzy_basis;
  36 extern int read_batch;
  37 extern int write_batch;
  38 extern int delay_updates;
  39 extern int checksum_seed;
  40 extern int basis_dir_cnt;
  41 extern int prune_empty_dirs;
  42 extern int protocol_version;
  43 extern int protect_args;
  44 extern int preserve_uid;
  45 extern int preserve_gid;
  46 extern int preserve_atimes;
  47 extern int preserve_crtimes;
  48 extern int preserve_acls;
  49 extern int preserve_xattrs;
  50 extern int xfer_flags_as_varint;
  51 extern int need_messages_from_generator;
  52 extern int delete_mode, delete_before, delete_during, delete_after;
  53 extern int do_compression;
  54 extern int do_compression_level;
  55 extern int saw_stderr_opt;
  56 extern int msgs2stderr;
  57 extern char *shell_cmd;
  58 extern char *partial_dir;
  59 extern char *files_from;
  60 extern char *filesfrom_host;
  61 extern const char *checksum_choice;
  62 extern const char *compress_choice;
  63 extern filter_rule_list filter_list;
  64 extern int need_unsorted_flist;
  65 #ifdef ICONV_OPTION
  66 extern iconv_t ic_send, ic_recv;
  67 extern char *iconv_opt;
  68 #endif
  69 extern struct name_num_obj valid_checksums;
  70
  71 int remote_protocol = 0;
  72 int file_extra_cnt = 0; /* count of file-list extras that everyone gets */
  73 int inc_recurse = 0;
  74 int compat_flags = 0;
  75 int use_safe_inc_flist = 0;
  76 int want_xattr_optim = 0;
  77 int proper_seed_order = 0;
  78 int inplace_partial = 0;
  79 int do_negotiated_strings = 0;
  80 int xmit_id0_names = 0;
  81
  82 /* These index values are for the file-list's extra-attribute array. */
  83 int pathname_ndx, depth_ndx, atimes_ndx, crtimes_ndx, uid_ndx, gid_ndx, acls_ndx, xattrs_ndx, unsort_ndx;
  84
  85 int receiver_symlink_times = 0; /* receiver can set the time on a symlink */
  86 int sender_symlink_iconv = 0;   /* sender should convert symlink content */
  87
  88 #ifdef ICONV_OPTION
  89 int filesfrom_convert = 0;
  90 #endif
  91
  92 #define MAX_NSTR_STRLEN 256
  93
  94 struct name_num_item valid_compressions_items[] = {
  95 #ifdef SUPPORT_ZSTD
  96         { CPRES_ZSTD, "zstd", NULL },
  97 #endif
  98 #ifdef SUPPORT_LZ4
  99         { CPRES_LZ4, "lz4", NULL },
 100 #endif
 101         { CPRES_ZLIBX, "zlibx", NULL },
 102         { CPRES_ZLIB, "zlib", NULL },
 103         { CPRES_NONE, "none", NULL },
 104         { 0, NULL, NULL }
 105 };
 106
 107 struct name_num_obj valid_compressions = {
 108         "compress", NULL, NULL, 0, 0, valid_compressions_items
 109 };
 110
 111 #define CF_INC_RECURSE   (1<<0)
 112 #define CF_SYMLINK_TIMES (1<<1)
 113 #define CF_SYMLINK_ICONV (1<<2)
 114 #define CF_SAFE_FLIST    (1<<3)
 115 #define CF_AVOID_XATTR_OPTIM (1<<4)
 116 #define CF_CHKSUM_SEED_FIX (1<<5)
 117 #define CF_INPLACE_PARTIAL_DIR (1<<6)
 118 #define CF_VARINT_FLIST_FLAGS (1<<7)
 119 #define CF_ID0_NAMES (1<<8)
 120
 121 static const char *client_info;
 122
 123 /* The server makes sure that if either side only supports a pre-release
 124  * version of a protocol, that both sides must speak a compatible version
 125  * of that protocol for it to be advertised as available. */
 126 static void check_sub_protocol(void)
 127 {
 128         char *dot;
 129         int their_protocol, their_sub;
 130 #if SUBPROTOCOL_VERSION != 0
 131         int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
 132 #else
 133         int our_sub = 0;
 134 #endif
 135
 136         /* client_info starts with VER.SUB string if client is a pre-release. */
 137         if (!(their_protocol = atoi(client_info))
 138          || !(dot = strchr(client_info, '.'))
 139          || !(their_sub = atoi(dot+1))) {
 140 #if SUBPROTOCOL_VERSION != 0
 141                 if (our_sub)
 142                         protocol_version--;
 143 #endif
 144                 return;
 145         }
 146
 147         if (their_protocol < protocol_version) {
 148                 if (their_sub)
 149                         protocol_version = their_protocol - 1;
 150                 return;
 151         }
 152
 153         if (their_protocol > protocol_version)
 154                 their_sub = 0; /* 0 == final version of older protocol */
 155         if (their_sub != our_sub)
 156                 protocol_version--;
 157 }
 158
 159 void set_allow_inc_recurse(void)
 160 {
 161         if (!local_server)
 162                 client_info = shell_cmd ? shell_cmd : "";
 163         else if (am_server) {
 164                 char buf[64];
 165                 maybe_add_e_option(buf, sizeof buf);
 166                 client_info = *buf ? strdup(buf+1) : ""; /* The +1 skips the leading "e". */
 167         }
 168
 169         if (!recurse || use_qsort)
 170                 allow_inc_recurse = 0;
 171         else if (!am_sender
 172          && (delete_before || delete_after
 173           || delay_updates || prune_empty_dirs))
 174                 allow_inc_recurse = 0;
 175         else if (am_server && strchr(client_info, 'i') == NULL)
 176                 allow_inc_recurse = 0;
 177 }
 178
 179 void parse_compress_choice(int final_call)
 180 {
 181         if (valid_compressions.negotiated_name)
 182                 do_compression = valid_compressions.negotiated_num;
 183         else if (compress_choice) {
 184                 struct name_num_item *nni = get_nni_by_name(&valid_compressions, compress_choice, -1);
 185                 if (!nni) {
 186                         rprintf(FERROR, "unknown compress name: %s\n", compress_choice);
 187                         exit_cleanup(RERR_UNSUPPORTED);
 188                 }
 189                 do_compression = nni->num;
 190                 if (am_server)
 191                         validate_choice_vs_env(NSTR_COMPRESS, do_compression, -1);
 192         } else if (do_compression)
 193                 do_compression = CPRES_ZLIB;
 194         else
 195                 do_compression = CPRES_NONE;
 196
 197         if (do_compression != CPRES_NONE && final_call)
 198                 init_compression_level(); /* There's a chance this might turn compression off! */
 199
 200         if (do_compression == CPRES_NONE)
 201                 compress_choice = NULL;
 202
 203         /* Snag the compression name for both write_batch's option output & the following debug output. */
 204         if (valid_compressions.negotiated_name)
 205                 compress_choice = valid_compressions.negotiated_name;
 206         else if (compress_choice == NULL) {
 207                 struct name_num_item *nni = get_nni_by_num(&valid_compressions, do_compression);
 208                 compress_choice = nni ? nni->name : "UNKNOWN";
 209         }
 210
 211         if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)
 212          && (do_compression != CPRES_NONE || do_compression_level != CLVL_NOT_SPECIFIED)) {
 213                 rprintf(FINFO, "%s%s compress: %s (level %d)\n",
 214                         am_server ? "Server" : "Client",
 215                         valid_compressions.negotiated_name ? " negotiated" : "",
 216                         compress_choice, do_compression_level);
 217         }
 218 }
 219
 220 struct name_num_item *get_nni_by_name(struct name_num_obj *nno, const char *name, int len)
 221 {
 222         struct name_num_item *nni;
 223
 224         if (len < 0)
 225                 len = strlen(name);
 226
 227         for (nni = nno->list; nni->name; nni++) {
 228                 if (strncasecmp(name, nni->name, len) == 0 && nni->name[len] == '\0')
 229                         return nni;
 230         }
 231
 232         return NULL;
 233 }
 234
 235 struct name_num_item *get_nni_by_num(struct name_num_obj *nno, int num)
 236 {
 237         struct name_num_item *nni;
 238
 239         for (nni = nno->list; nni->name; nni++) {
 240                 if (num == nni->num)
 241                         return nni;
 242         }
 243
 244         return NULL;
 245 }
 246
 247 static void init_nno_saw(struct name_num_obj *nno, int val)
 248 {
 249         struct name_num_item *nni;
 250         int cnt;
 251
 252         if (!nno->saw_len) {
 253                 for (nni = nno->list; nni->name; nni++) {
 254                         if (nni->num >= nno->saw_len)
 255                                 nno->saw_len = nni->num + 1;
 256                 }
 257         }
 258
 259         if (!nno->saw) {
 260                 nno->saw = new_array0(uchar, nno->saw_len);
 261
 262                 /* We'll take this opportunity to make sure that the main_name values are set right. */
 263                 for (cnt = 1, nni = nno->list; nni->name; nni++, cnt++) {
 264                         if (nno->saw[nni->num])
 265                                 nni->main_name = nno->list[nno->saw[nni->num]-1].name;
 266                         else
 267                                 nno->saw[nni->num] = cnt;
 268                 }
 269         }
 270
 271         memset(nno->saw, val, nno->saw_len);
 272 }
 273
 274 /* Simplify the user-provided string so that it contains valid names without any duplicates.
 275  * It also sets the "saw" flags to a 1-relative count of which name was seen first. */
 276 static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf, int tobuf_len)
 277 {
 278         char *to = tobuf, *tok = NULL;
 279         int saw_tok = 0, cnt = 0;
 280
 281         while (1) {
 282                 int at_space = isSpace(from);
 283                 char ch = *from++;
 284                 if (ch == '&')
 285                         ch = '\0';
 286                 if (!ch || at_space) {
 287                         if (tok) {
 288                                 struct name_num_item *nni = get_nni_by_name(nno, tok, to - tok);
 289                                 if (nni && !nno->saw[nni->num]) {
 290                                         nno->saw[nni->num] = ++cnt;
 291                                         if (nni->main_name) {
 292                                                 to = tok + strlcpy(tok, nni->main_name, tobuf_len - (tok - tobuf));
 293                                                 if (to - tobuf >= tobuf_len) {
 294                                                         to = tok - 1;
 295                                                         break;
 296                                                 }
 297                                         }
 298                                 } else
 299                                         to = tok - (tok != tobuf);
 300                                 saw_tok = 1;
 301                                 tok = NULL;
 302                         }
 303                         if (!ch)
 304                                 break;
 305                         continue;
 306                 }
 307                 if (!tok) {
 308                         if (to != tobuf)
 309                                 *to++ = ' ';
 310                         tok = to;
 311                 }
 312                 if (to - tobuf >= tobuf_len - 1) {
 313                         to = tok - (tok != tobuf);
 314                         break;
 315                 }
 316                 *to++ = ch;
 317         }
 318         *to = '\0';
 319
 320         if (saw_tok && to == tobuf)
 321                 return strlcpy(tobuf, "INVALID", MAX_NSTR_STRLEN);
 322
 323         return to - tobuf;
 324 }
 325
 326 /* This routine is always called with a tmpbuf of MAX_NSTR_STRLEN length, but the
 327  * buffer may be pre-populated with a "len" length string to use OR a len of -1
 328  * to tell us to read a string from the fd. */
 329 static void recv_negotiate_str(int f_in, struct name_num_obj *nno, char *tmpbuf, int len)
 330 {
 331         struct name_num_item *ret = NULL;
 332
 333         if (len < 0)
 334                 len = read_vstring(f_in, tmpbuf, MAX_NSTR_STRLEN);
 335
 336         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 337                 if (am_server)
 338                         rprintf(FINFO, "Client %s list (on server): %s\n", nno->type, tmpbuf);
 339                 else
 340                         rprintf(FINFO, "Server %s list (on client): %s\n", nno->type, tmpbuf);
 341         }
 342
 343         if (len > 0) {
 344                 struct name_num_item *nni;
 345                 int best = nno->saw_len; /* We want best == 1 from the client list, so start with a big number. */
 346                 char *space, *tok = tmpbuf;
 347                 while (tok) {
 348                         while (*tok == ' ') tok++; /* Should be unneeded... */
 349                         if (!*tok)
 350                                 break;
 351                         if ((space = strchr(tok, ' ')) != NULL)
 352                                 *space = '\0';
 353                         nni = get_nni_by_name(nno, tok, -1);
 354                         if (space) {
 355                                 *space = ' ';
 356                                 tok = space + 1;
 357                         } else
 358                                 tok = NULL;
 359                         if (!nni || !nno->saw[nni->num] || best <= nno->saw[nni->num])
 360                                 continue;
 361                         ret = nni;
 362                         best = nno->saw[nni->num];
 363                         if (best == 1 || am_server) /* The server side stops at the first acceptable client choice */
 364                                 break;
 365                 }
 366                 if (ret) {
 367                         free(nno->saw);
 368                         nno->saw = NULL;
 369                         nno->negotiated_name = ret->main_name ? ret->main_name : ret->name;
 370                         nno->negotiated_num = ret->num;
 371                         return;
 372                 }
 373         }
 374
 375         if (!am_server || !do_negotiated_strings) {
 376                 char *cp = tmpbuf;
 377                 int j;
 378                 rprintf(FERROR, "Failed to negotiate a %s choice.\n", nno->type);
 379                 rprintf(FERROR, "%s list: %s\n", am_server ? "Client" : "Server", tmpbuf);
 380                 /* Recreate our original list from the saw values. This can't overflow our huge
 381                  * buffer because we don't have enough valid entries to get anywhere close. */
 382                 for (j = 1, *cp = '\0'; j <= nno->saw_len; j++) {
 383                         struct name_num_item *nni;
 384                         for (nni = nno->list; nni->name; nni++) {
 385                                 if (nno->saw[nni->num] == j) {
 386                                         *cp++ = ' ';
 387                                         cp += strlcpy(cp, nni->name, MAX_NSTR_STRLEN - (cp - tmpbuf));
 388                                         break;
 389                                 }
 390                         }
 391                 }
 392                 if (!*tmpbuf)
 393                         strlcpy(cp, " INVALID", MAX_NSTR_STRLEN);
 394                 rprintf(FERROR, "%s list:%s\n", am_server ? "Server" : "Client", tmpbuf);
 395         }
 396
 397         exit_cleanup(RERR_UNSUPPORTED);
 398 }
 399
 400 static const char *getenv_nstr(int ntype)
 401 {
 402         const char *env_str = getenv(ntype == NSTR_COMPRESS ? "RSYNC_COMPRESS_LIST" : "RSYNC_CHECKSUM_LIST");
 403
 404         /* When writing a batch file, we always negotiate an old-style choice. */
 405         if (write_batch)
 406                 env_str = ntype == NSTR_COMPRESS ? "zlib" : protocol_version >= 30 ? "md5" : "md4";
 407
 408         if (am_server && env_str) {
 409                 char *cp = strchr(env_str, '&');
 410                 if (cp)
 411                         env_str = cp + 1;
 412         }
 413
 414         return env_str;
 415 }
 416
 417 void validate_choice_vs_env(int ntype, int num1, int num2)
 418 {
 419         struct name_num_obj *nno = ntype == NSTR_COMPRESS ? &valid_compressions : &valid_checksums;
 420         const char *list_str = getenv_nstr(ntype);
 421         char tmpbuf[MAX_NSTR_STRLEN];
 422
 423         if (!list_str)
 424                 return;
 425
 426         while (isSpace(list_str)) list_str++;
 427
 428         if (!*list_str)
 429                 return;
 430
 431         init_nno_saw(nno, 0);
 432         parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 433
 434         if (ntype == NSTR_CHECKSUM) /* If "md4" is in the env list, all the old MD4 choices are OK too. */
 435                 nno->saw[CSUM_MD4_ARCHAIC] = nno->saw[CSUM_MD4_BUSTED] = nno->saw[CSUM_MD4_OLD] = nno->saw[CSUM_MD4];
 436
 437         if (!nno->saw[num1] || (num2 >= 0 && !nno->saw[num2])) {
 438                 rprintf(FERROR, "Your --%s-choice value (%s) was refused by the server.\n",
 439                         ntype == NSTR_COMPRESS ? "compress" : "checksum",
 440                         ntype == NSTR_COMPRESS ? compress_choice : checksum_choice);
 441                 exit_cleanup(RERR_UNSUPPORTED);
 442         }
 443
 444         free(nno->saw);
 445         nno->saw = NULL;
 446 }
 447
 448 /* The saw buffer is initialized and used to store ordinal values from 1 to N
 449  * for the order of the args in the array.  If dup_markup == '\0', duplicates
 450  * are removed otherwise the char is prefixed to the duplicate term and, if it
 451  * is an opening paren/bracket/brace, the matching closing char is suffixed.
 452  * "none" is removed on the client side unless dup_markup != '\0'. */
 453 int get_default_nno_list(struct name_num_obj *nno, char *to_buf, int to_buf_len, char dup_markup)
 454 {
 455         struct name_num_item *nni;
 456         int len = 0, cnt = 0;
 457         char delim = '\0', post_delim;
 458
 459         switch (dup_markup) {
 460         case '(': post_delim = ')'; break;
 461         case '[': post_delim = ']'; break;
 462         case '{': post_delim = '}'; break;
 463         default: post_delim = '\0'; break;
 464         }
 465
 466         init_nno_saw(nno, 0);
 467
 468         for (nni = nno->list, len = 0; nni->name; nni++) {
 469                 if (nni->main_name) {
 470                         if (!dup_markup)
 471                                 continue;
 472                         delim = dup_markup;
 473                 }
 474                 if (nni->num == 0 && !am_server && !dup_markup)
 475                         continue;
 476                 if (len)
 477                         to_buf[len++]= ' ';
 478                 if (delim) {
 479                         to_buf[len++]= delim;
 480                         delim = post_delim;
 481                 }
 482                 len += strlcpy(to_buf+len, nni->name, to_buf_len - len);
 483                 if (len >= to_buf_len - 3)
 484                         exit_cleanup(RERR_UNSUPPORTED); /* IMPOSSIBLE... */
 485                 if (delim) {
 486                         to_buf[len++]= delim;
 487                         delim = '\0';
 488                 }
 489                 nno->saw[nni->num] = ++cnt;
 490         }
 491
 492         return len;
 493 }
 494
 495 static void send_negotiate_str(int f_out, struct name_num_obj *nno, int ntype)
 496 {
 497         char tmpbuf[MAX_NSTR_STRLEN];
 498         const char *list_str = getenv_nstr(ntype);
 499         int len;
 500
 501         if (list_str && *list_str) {
 502                 init_nno_saw(nno, 0);
 503                 len = parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 504                 list_str = tmpbuf;
 505         } else
 506                 list_str = NULL;
 507
 508         if (!list_str || !*list_str)
 509                 len = get_default_nno_list(nno, tmpbuf, MAX_NSTR_STRLEN, '\0');
 510
 511         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 512                 if (am_server)
 513                         rprintf(FINFO, "Server %s list (on server): %s\n", nno->type, tmpbuf);
 514                 else
 515                         rprintf(FINFO, "Client %s list (on client): %s\n", nno->type, tmpbuf);
 516         }
 517
 518         /* Each side sends their list of valid names to the other side and then both sides
 519          * pick the first name in the client's list that is also in the server's list. */
 520         if (do_negotiated_strings)
 521                 write_vstring(f_out, tmpbuf, len);
 522 }
 523
 524 static void negotiate_the_strings(int f_in, int f_out)
 525 {
 526         /* We send all the negotiation strings before we start to read them to help avoid a slow startup. */
 527
 528         init_checksum_choices();
 529
 530         if (!checksum_choice)
 531                 send_negotiate_str(f_out, &valid_checksums, NSTR_CHECKSUM);
 532
 533         if (do_compression && !compress_choice)
 534                 send_negotiate_str(f_out, &valid_compressions, NSTR_COMPRESS);
 535
 536         if (valid_checksums.saw) {
 537                 char tmpbuf[MAX_NSTR_STRLEN];
 538                 int len;
 539                 if (do_negotiated_strings)
 540                         len = -1;
 541                 else
 542                         len = strlcpy(tmpbuf, protocol_version >= 30 ? "md5" : "md4", MAX_NSTR_STRLEN);
 543                 recv_negotiate_str(f_in, &valid_checksums, tmpbuf, len);
 544         }
 545
 546         if (valid_compressions.saw) {
 547                 char tmpbuf[MAX_NSTR_STRLEN];
 548                 int len;
 549                 if (do_negotiated_strings)
 550                         len = -1;
 551                 else
 552                         len = strlcpy(tmpbuf, "zlib", MAX_NSTR_STRLEN);
 553                 recv_negotiate_str(f_in, &valid_compressions, tmpbuf, len);
 554         }
 555
 556         /* If the other side is too old to negotiate, the above steps just made sure that
 557          * the env didn't disallow the old algorithm. Mark things as non-negotiated. */
 558         if (!do_negotiated_strings)
 559                 valid_checksums.negotiated_name = valid_compressions.negotiated_name = NULL;
 560 }
 561
 562 void setup_protocol(int f_out,int f_in)
 563 {
 564         assert(file_extra_cnt == 0);
 565         assert(EXTRA64_CNT == 2 || EXTRA64_CNT == 1);
 566
 567         /* All int64 values must be set first so that they are guaranteed to be
 568          * aligned for direct int64-pointer memory access. */
 569         if (preserve_atimes)
 570                 atimes_ndx = (file_extra_cnt += EXTRA64_CNT);
 571         if (preserve_crtimes)
 572                 crtimes_ndx = (file_extra_cnt += EXTRA64_CNT);
 573         if (am_sender) /* This is most likely in the file_extras64 union as well. */
 574                 pathname_ndx = (file_extra_cnt += PTR_EXTRA_CNT);
 575         else
 576                 depth_ndx = ++file_extra_cnt;
 577         if (preserve_uid)
 578                 uid_ndx = ++file_extra_cnt;
 579         if (preserve_gid)
 580                 gid_ndx = ++file_extra_cnt;
 581         if (preserve_acls && !am_sender)
 582                 acls_ndx = ++file_extra_cnt;
 583         if (preserve_xattrs)
 584                 xattrs_ndx = ++file_extra_cnt;
 585
 586         if (am_server)
 587                 set_allow_inc_recurse();
 588
 589         if (remote_protocol == 0) {
 590                 if (am_server && !local_server)
 591                         check_sub_protocol();
 592                 if (!read_batch)
 593                         write_int(f_out, protocol_version);
 594                 remote_protocol = read_int(f_in);
 595                 if (protocol_version > remote_protocol)
 596                         protocol_version = remote_protocol;
 597         }
 598         if (read_batch && remote_protocol > protocol_version) {
 599                 rprintf(FERROR, "The protocol version in the batch file is too new (%d > %d).\n",
 600                         remote_protocol, protocol_version);
 601                 exit_cleanup(RERR_PROTOCOL);
 602         }
 603
 604         if (DEBUG_GTE(PROTO, 1)) {
 605                 rprintf(FINFO, "(%s) Protocol versions: remote=%d, negotiated=%d\n",
 606                         am_server? "Server" : "Client", remote_protocol, protocol_version);
 607         }
 608         if (remote_protocol < MIN_PROTOCOL_VERSION
 609          || remote_protocol > MAX_PROTOCOL_VERSION) {
 610                 rprintf(FERROR,"protocol version mismatch -- is your shell clean?\n");
 611                 rprintf(FERROR,"(see the rsync manpage for an explanation)\n");
 612                 exit_cleanup(RERR_PROTOCOL);
 613         }
 614         if (remote_protocol < OLD_PROTOCOL_VERSION) {
 615                 rprintf(FINFO,"%s is very old version of rsync, upgrade recommended.\n",
 616                         am_server? "Client" : "Server");
 617         }
 618         if (protocol_version < MIN_PROTOCOL_VERSION) {
 619                 rprintf(FERROR, "--protocol must be at least %d on the %s.\n",
 620                         MIN_PROTOCOL_VERSION, am_server? "Server" : "Client");
 621                 exit_cleanup(RERR_PROTOCOL);
 622         }
 623         if (protocol_version > PROTOCOL_VERSION) {
 624                 rprintf(FERROR, "--protocol must be no more than %d on the %s.\n",
 625                         PROTOCOL_VERSION, am_server? "Server" : "Client");
 626                 exit_cleanup(RERR_PROTOCOL);
 627         }
 628         if (read_batch)
 629                 check_batch_flags();
 630
 631         if (!saw_stderr_opt && protocol_version <= 28 && am_server)
 632                 msgs2stderr = 0; /* The client side may not have stderr setup for us. */
 633
 634 #ifndef SUPPORT_PREALLOCATION
 635         if (preallocate_files && !am_sender) {
 636                 rprintf(FERROR, "preallocation is not supported on this %s\n",
 637                         am_server ? "Server" : "Client");
 638                 exit_cleanup(RERR_SYNTAX);
 639         }
 640 #endif
 641
 642         if (protocol_version < 30) {
 643                 if (append_mode == 1)
 644                         append_mode = 2;
 645                 if (preserve_acls && !local_server) {
 646                         rprintf(FERROR,
 647                                 "--acls requires protocol 30 or higher"
 648                                 " (negotiated %d).\n",
 649                                 protocol_version);
 650                         exit_cleanup(RERR_PROTOCOL);
 651                 }
 652                 if (preserve_xattrs && !local_server) {
 653                         rprintf(FERROR,
 654                                 "--xattrs requires protocol 30 or higher"
 655                                 " (negotiated %d).\n",
 656                                 protocol_version);
 657                         exit_cleanup(RERR_PROTOCOL);
 658                 }
 659         }
 660
 661         if (delete_mode && !(delete_before+delete_during+delete_after)) {
 662                 if (protocol_version < 30)
 663                         delete_before = 1;
 664                 else
 665                         delete_during = 1;
 666         }
 667
 668         if (protocol_version < 29) {
 669                 if (fuzzy_basis) {
 670                         rprintf(FERROR,
 671                                 "--fuzzy requires protocol 29 or higher"
 672                                 " (negotiated %d).\n",
 673                                 protocol_version);
 674                         exit_cleanup(RERR_PROTOCOL);
 675                 }
 676
 677                 if (basis_dir_cnt && inplace) {
 678                         rprintf(FERROR,
 679                                 "%s with --inplace requires protocol 29 or higher"
 680                                 " (negotiated %d).\n",
 681                                 alt_dest_opt(0), protocol_version);
 682                         exit_cleanup(RERR_PROTOCOL);
 683                 }
 684
 685                 if (basis_dir_cnt > 1) {
 686                         rprintf(FERROR,
 687                                 "Using more than one %s option requires protocol"
 688                                 " 29 or higher (negotiated %d).\n",
 689                                 alt_dest_opt(0), protocol_version);
 690                         exit_cleanup(RERR_PROTOCOL);
 691                 }
 692
 693                 if (prune_empty_dirs) {
 694                         rprintf(FERROR,
 695                                 "--prune-empty-dirs requires protocol 29 or higher"
 696                                 " (negotiated %d).\n",
 697                                 protocol_version);
 698                         exit_cleanup(RERR_PROTOCOL);
 699                 }
 700         } else if (protocol_version >= 30) {
 701                 if (am_server) {
 702                         compat_flags = allow_inc_recurse ? CF_INC_RECURSE : 0;
 703 #ifdef CAN_SET_SYMLINK_TIMES
 704                         compat_flags |= CF_SYMLINK_TIMES;
 705 #endif
 706 #ifdef ICONV_OPTION
 707                         compat_flags |= CF_SYMLINK_ICONV;
 708 #endif
 709                         if (strchr(client_info, 'f') != NULL)
 710                                 compat_flags |= CF_SAFE_FLIST;
 711                         if (strchr(client_info, 'x') != NULL)
 712                                 compat_flags |= CF_AVOID_XATTR_OPTIM;
 713                         if (strchr(client_info, 'C') != NULL)
 714                                 compat_flags |= CF_CHKSUM_SEED_FIX;
 715                         if (strchr(client_info, 'I') != NULL)
 716                                 compat_flags |= CF_INPLACE_PARTIAL_DIR;
 717                         if (strchr(client_info, 'u') != NULL)
 718                                 compat_flags |= CF_ID0_NAMES;
 719                         if (strchr(client_info, 'v') != NULL) {
 720                                 do_negotiated_strings = 1;
 721                                 compat_flags |= CF_VARINT_FLIST_FLAGS;
 722                         }
 723                         if (strchr(client_info, 'V') != NULL) { /* Support a pre-release 'V' that got superseded */
 724                                 if (!write_batch)
 725                                         compat_flags |= CF_VARINT_FLIST_FLAGS;
 726                                 write_byte(f_out, compat_flags);
 727                         } else
 728                                 write_varint(f_out, compat_flags);
 729                 } else { /* read_varint() is compatible with the older write_byte() when the 0x80 bit isn't on. */
 730                         compat_flags = read_varint(f_in);
 731                         if  (compat_flags & CF_VARINT_FLIST_FLAGS)
 732                                 do_negotiated_strings = 1;
 733                 }
 734                 /* The inc_recurse var MUST be set to 0 or 1. */
 735                 inc_recurse = compat_flags & CF_INC_RECURSE ? 1 : 0;
 736                 want_xattr_optim = protocol_version >= 31 && !(compat_flags & CF_AVOID_XATTR_OPTIM);
 737                 proper_seed_order = compat_flags & CF_CHKSUM_SEED_FIX ? 1 : 0;
 738                 xfer_flags_as_varint = compat_flags & CF_VARINT_FLIST_FLAGS ? 1 : 0;
 739                 xmit_id0_names = compat_flags & CF_ID0_NAMES ? 1 : 0;
 740                 if (!xfer_flags_as_varint && preserve_crtimes) {
 741                         fprintf(stderr, "Both rsync versions must be at least 3.2.0 for --crtimes.\n");
 742                         exit_cleanup(RERR_PROTOCOL);
 743                 }
 744                 if (am_sender) {
 745                         receiver_symlink_times = am_server
 746                             ? strchr(client_info, 'L') != NULL
 747                             : !!(compat_flags & CF_SYMLINK_TIMES);
 748                 }
 749 #ifdef CAN_SET_SYMLINK_TIMES
 750                 else
 751                         receiver_symlink_times = 1;
 752 #endif
 753 #ifdef ICONV_OPTION
 754                 sender_symlink_iconv = iconv_opt && (am_server
 755                     ? strchr(client_info, 's') != NULL
 756                     : !!(compat_flags & CF_SYMLINK_ICONV));
 757 #endif
 758                 if (inc_recurse && !allow_inc_recurse) {
 759                         /* This should only be able to happen in a batch. */
 760                         fprintf(stderr,
 761                                 "Incompatible options specified for inc-recursive %s.\n",
 762                                 read_batch ? "batch file" : "connection");
 763                         exit_cleanup(RERR_SYNTAX);
 764                 }
 765                 use_safe_inc_flist = (compat_flags & CF_SAFE_FLIST) || protocol_version >= 31;
 766                 need_messages_from_generator = 1;
 767                 if (compat_flags & CF_INPLACE_PARTIAL_DIR)
 768                         inplace_partial = 1;
 769 #ifdef CAN_SET_SYMLINK_TIMES
 770         } else if (!am_sender) {
 771                 receiver_symlink_times = 1;
 772 #endif
 773         }
 774
 775         if (read_batch)
 776                 do_negotiated_strings = 0;
 777
 778         if (need_unsorted_flist && (!am_sender || inc_recurse))
 779                 unsort_ndx = ++file_extra_cnt;
 780
 781         if (partial_dir && *partial_dir != '/' && (!am_server || local_server)) {
 782                 int rflags = FILTRULE_NO_PREFIXES | FILTRULE_DIRECTORY;
 783                 if (!am_sender || protocol_version >= 30)
 784                         rflags |= FILTRULE_PERISHABLE;
 785                 parse_filter_str(&filter_list, partial_dir, rule_template(rflags), 0);
 786         }
 787
 788
 789 #ifdef ICONV_OPTION
 790         if (protect_args && files_from) {
 791                 if (am_sender)
 792                         filesfrom_convert = filesfrom_host && ic_send != (iconv_t)-1;
 793                 else
 794                         filesfrom_convert = !filesfrom_host && ic_recv != (iconv_t)-1;
 795         }
 796 #endif
 797
 798         negotiate_the_strings(f_in, f_out);
 799
 800         if (am_server) {
 801                 if (!checksum_seed)
 802                         checksum_seed = time(NULL) ^ (getpid() << 6);
 803                 write_int(f_out, checksum_seed);
 804         } else {
 805                 checksum_seed = read_int(f_in);
 806         }
 807
 808         parse_checksum_choice(1); /* Sets checksum_type & xfersum_type */
 809         parse_compress_choice(1); /* Sets do_compression */
 810
 811         if (write_batch && !am_server)
 812                 write_batch_shell_file();
 813
 814         init_flist();
 815 }