compat.c

   1 /*
   2  * Compatibility routines for older rsync protocol versions.
   3  *
   4  * Copyright (C) Andrew Tridgell 1996
   5  * Copyright (C) Paul Mackerras 1996
   6  * Copyright (C) 2004-2020 Wayne Davison
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, visit the http://fsf.org website.
  20  */
  21
  22 #include "rsync.h"
  23 #include "itypes.h"
  24 #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 char *shell_cmd;
  56 extern char *partial_dir;
  57 extern char *files_from;
  58 extern char *filesfrom_host;
  59 extern const char *checksum_choice;
  60 extern const char *compress_choice;
  61 extern filter_rule_list filter_list;
  62 extern int need_unsorted_flist;
  63 #ifdef ICONV_OPTION
  64 extern iconv_t ic_send, ic_recv;
  65 extern char *iconv_opt;
  66 #endif
  67 extern struct name_num_obj valid_checksums;
  68
  69 int remote_protocol = 0;
  70 int file_extra_cnt = 0; /* count of file-list extras that everyone gets */
  71 int inc_recurse = 0;
  72 int compat_flags = 0;
  73 int use_safe_inc_flist = 0;
  74 int want_xattr_optim = 0;
  75 int proper_seed_order = 0;
  76 int inplace_partial = 0;
  77 int do_negotiated_strings = 0;
  78 int xmit_id0_names = 0;
  79
  80 /* These index values are for the file-list's extra-attribute array. */
  81 int pathname_ndx, depth_ndx, atimes_ndx, crtimes_ndx, uid_ndx, gid_ndx, acls_ndx, xattrs_ndx, unsort_ndx;
  82
  83 int receiver_symlink_times = 0; /* receiver can set the time on a symlink */
  84 int sender_symlink_iconv = 0;   /* sender should convert symlink content */
  85
  86 #ifdef ICONV_OPTION
  87 int filesfrom_convert = 0;
  88 #endif
  89
  90 #define MAX_NSTR_STRLEN 256
  91
  92 struct name_num_obj valid_compressions = {
  93         "compress", NULL, NULL, 0, 0, {
  94 #ifdef SUPPORT_ZSTD
  95                 { CPRES_ZSTD, "zstd", NULL },
  96 #endif
  97 #ifdef SUPPORT_LZ4
  98                 { CPRES_LZ4, "lz4", NULL },
  99 #endif
 100                 { CPRES_ZLIBX, "zlibx", NULL },
 101                 { CPRES_ZLIB, "zlib", NULL },
 102                 { CPRES_NONE, "none", NULL },
 103                 { 0, NULL, NULL }
 104         }
 105 };
 106
 107 #define CF_INC_RECURSE   (1<<0)
 108 #define CF_SYMLINK_TIMES (1<<1)
 109 #define CF_SYMLINK_ICONV (1<<2)
 110 #define CF_SAFE_FLIST    (1<<3)
 111 #define CF_AVOID_XATTR_OPTIM (1<<4)
 112 #define CF_CHKSUM_SEED_FIX (1<<5)
 113 #define CF_INPLACE_PARTIAL_DIR (1<<6)
 114 #define CF_VARINT_FLIST_FLAGS (1<<7)
 115 #define CF_ID0_NAMES (1<<8)
 116
 117 static const char *client_info;
 118
 119 /* The server makes sure that if either side only supports a pre-release
 120  * version of a protocol, that both sides must speak a compatible version
 121  * of that protocol for it to be advertised as available. */
 122 static void check_sub_protocol(void)
 123 {
 124         char *dot;
 125         int their_protocol, their_sub;
 126 #if SUBPROTOCOL_VERSION != 0
 127         int our_sub = protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
 128 #else
 129         int our_sub = 0;
 130 #endif
 131
 132         /* client_info starts with VER.SUB string if client is a pre-release. */
 133         if (!(their_protocol = atoi(client_info))
 134          || !(dot = strchr(client_info, '.'))
 135          || !(their_sub = atoi(dot+1))) {
 136 #if SUBPROTOCOL_VERSION != 0
 137                 if (our_sub)
 138                         protocol_version--;
 139 #endif
 140                 return;
 141         }
 142
 143         if (their_protocol < protocol_version) {
 144                 if (their_sub)
 145                         protocol_version = their_protocol - 1;
 146                 return;
 147         }
 148
 149         if (their_protocol > protocol_version)
 150                 their_sub = 0; /* 0 == final version of older protocol */
 151         if (their_sub != our_sub)
 152                 protocol_version--;
 153 }
 154
 155 void set_allow_inc_recurse(void)
 156 {
 157         if (!local_server)
 158                 client_info = shell_cmd ? shell_cmd : "";
 159         else if (am_server) {
 160                 char buf[64];
 161                 maybe_add_e_option(buf, sizeof buf);
 162                 client_info = *buf ? strdup(buf+1) : ""; /* The +1 skips the leading "e". */
 163         }
 164
 165         if (!recurse || use_qsort)
 166                 allow_inc_recurse = 0;
 167         else if (!am_sender
 168          && (delete_before || delete_after
 169           || delay_updates || prune_empty_dirs))
 170                 allow_inc_recurse = 0;
 171         else if (am_server && strchr(client_info, 'i') == NULL)
 172                 allow_inc_recurse = 0;
 173 }
 174
 175 void parse_compress_choice(int final_call)
 176 {
 177         if (valid_compressions.negotiated_name)
 178                 do_compression = valid_compressions.negotiated_num;
 179         else if (compress_choice) {
 180                 struct name_num_item *nni = get_nni_by_name(&valid_compressions, compress_choice, -1);
 181                 if (!nni) {
 182                         rprintf(FERROR, "unknown compress name: %s\n", compress_choice);
 183                         exit_cleanup(RERR_UNSUPPORTED);
 184                 }
 185                 do_compression = nni->num;
 186                 if (am_server)
 187                         validate_choice_vs_env(NSTR_COMPRESS, do_compression, -1);
 188         } else if (do_compression)
 189                 do_compression = CPRES_ZLIB;
 190         else
 191                 do_compression = CPRES_NONE;
 192
 193         if (do_compression != CPRES_NONE && final_call)
 194                 init_compression_level(); /* There's a chance this might turn compression off! */
 195
 196         if (do_compression == CPRES_NONE)
 197                 compress_choice = NULL;
 198
 199         /* Snag the compression name for both write_batch's option output & the following debug output. */
 200         if (valid_compressions.negotiated_name)
 201                 compress_choice = valid_compressions.negotiated_name;
 202         else if (compress_choice == NULL) {
 203                 struct name_num_item *nni = get_nni_by_num(&valid_compressions, do_compression);
 204                 compress_choice = nni ? nni->name : "UNKNOWN";
 205         }
 206
 207         if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)
 208          && (do_compression != CPRES_NONE || do_compression_level != CLVL_NOT_SPECIFIED)) {
 209                 rprintf(FINFO, "%s%s compress: %s (level %d)\n",
 210                         am_server ? "Server" : "Client",
 211                         valid_compressions.negotiated_name ? " negotiated" : "",
 212                         compress_choice, do_compression_level);
 213         }
 214 }
 215
 216 struct name_num_item *get_nni_by_name(struct name_num_obj *nno, const char *name, int len)
 217 {
 218         struct name_num_item *nni;
 219
 220         if (len < 0)
 221                 len = strlen(name);
 222
 223         for (nni = nno->list; nni->name; nni++) {
 224                 if (strncasecmp(name, nni->name, len) == 0 && nni->name[len] == '\0')
 225                         return nni;
 226         }
 227
 228         return NULL;
 229 }
 230
 231 struct name_num_item *get_nni_by_num(struct name_num_obj *nno, int num)
 232 {
 233         struct name_num_item *nni;
 234
 235         for (nni = nno->list; nni->name; nni++) {
 236                 if (num == nni->num)
 237                         return nni;
 238         }
 239
 240         return NULL;
 241 }
 242
 243 static void init_nno_saw(struct name_num_obj *nno, int val)
 244 {
 245         struct name_num_item *nni;
 246         int cnt;
 247
 248         if (!nno->saw_len) {
 249                 for (nni = nno->list; nni->name; nni++) {
 250                         if (nni->num >= nno->saw_len)
 251                                 nno->saw_len = nni->num + 1;
 252                 }
 253         }
 254
 255         if (!nno->saw) {
 256                 nno->saw = new_array0(uchar, nno->saw_len);
 257
 258                 /* We'll take this opportunity to make sure that the main_name values are set right. */
 259                 for (cnt = 1, nni = nno->list; nni->name; nni++, cnt++) {
 260                         if (nno->saw[nni->num])
 261                                 nni->main_name = nno->list[nno->saw[nni->num]-1].name;
 262                         else
 263                                 nno->saw[nni->num] = cnt;
 264                 }
 265         }
 266
 267         memset(nno->saw, val, nno->saw_len);
 268 }
 269
 270 /* Simplify the user-provided string so that it contains valid names without any duplicates.
 271  * It also sets the "saw" flags to a 1-relative count of which name was seen first. */
 272 static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf, int tobuf_len)
 273 {
 274         char *to = tobuf, *tok = NULL;
 275         int saw_tok = 0, cnt = 0;
 276
 277         while (1) {
 278                 int at_space = isSpace(from);
 279                 char ch = *from++;
 280                 if (ch == '&')
 281                         ch = '\0';
 282                 if (!ch || at_space) {
 283                         if (tok) {
 284                                 struct name_num_item *nni = get_nni_by_name(nno, tok, to - tok);
 285                                 if (nni && !nno->saw[nni->num]) {
 286                                         nno->saw[nni->num] = ++cnt;
 287                                         if (nni->main_name) {
 288                                                 to = tok + strlcpy(tok, nni->main_name, tobuf_len - (tok - tobuf));
 289                                                 if (to - tobuf >= tobuf_len) {
 290                                                         to = tok - 1;
 291                                                         break;
 292                                                 }
 293                                         }
 294                                 } else
 295                                         to = tok - (tok != tobuf);
 296                                 saw_tok = 1;
 297                                 tok = NULL;
 298                         }
 299                         if (!ch)
 300                                 break;
 301                         continue;
 302                 }
 303                 if (!tok) {
 304                         if (to != tobuf)
 305                                 *to++ = ' ';
 306                         tok = to;
 307                 }
 308                 if (to - tobuf >= tobuf_len - 1) {
 309                         to = tok - (tok != tobuf);
 310                         break;
 311                 }
 312                 *to++ = ch;
 313         }
 314         *to = '\0';
 315
 316         if (saw_tok && to == tobuf)
 317                 return strlcpy(tobuf, "INVALID", MAX_NSTR_STRLEN);
 318
 319         return to - tobuf;
 320 }
 321
 322 /* This routine is always called with a tmpbuf of MAX_NSTR_STRLEN length, but the
 323  * buffer may be pre-populated with a "len" length string to use OR a len of -1
 324  * to tell us to read a string from the fd. */
 325 static void recv_negotiate_str(int f_in, struct name_num_obj *nno, char *tmpbuf, int len)
 326 {
 327         struct name_num_item *ret = NULL;
 328
 329         if (len < 0)
 330                 len = read_vstring(f_in, tmpbuf, MAX_NSTR_STRLEN);
 331
 332         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 333                 if (am_server)
 334                         rprintf(FINFO, "Client %s list (on server): %s\n", nno->type, tmpbuf);
 335                 else
 336                         rprintf(FINFO, "Server %s list (on client): %s\n", nno->type, tmpbuf);
 337         }
 338
 339         if (len > 0) {
 340                 struct name_num_item *nni;
 341                 int best = nno->saw_len; /* We want best == 1 from the client list, so start with a big number. */
 342                 char *space, *tok = tmpbuf;
 343                 while (tok) {
 344                         while (*tok == ' ') tok++; /* Should be unneeded... */
 345                         if (!*tok)
 346                                 break;
 347                         if ((space = strchr(tok, ' ')) != NULL)
 348                                 *space = '\0';
 349                         nni = get_nni_by_name(nno, tok, -1);
 350                         if (space) {
 351                                 *space = ' ';
 352                                 tok = space + 1;
 353                         } else
 354                                 tok = NULL;
 355                         if (!nni || !nno->saw[nni->num] || best <= nno->saw[nni->num])
 356                                 continue;
 357                         ret = nni;
 358                         best = nno->saw[nni->num];
 359                         if (best == 1 || am_server) /* The server side stops at the first acceptable client choice */
 360                                 break;
 361                 }
 362                 if (ret) {
 363                         free(nno->saw);
 364                         nno->saw = NULL;
 365                         nno->negotiated_name = ret->main_name ? ret->main_name : ret->name;
 366                         nno->negotiated_num = ret->num;
 367                         return;
 368                 }
 369         }
 370
 371         if (!am_server || !do_negotiated_strings) {
 372                 char *cp = tmpbuf;
 373                 int j;
 374                 rprintf(FERROR, "Failed to negotiate a %s choice.\n", nno->type);
 375                 rprintf(FERROR, "%s list: %s\n", am_server ? "Client" : "Server", tmpbuf);
 376                 /* Recreate our original list from the saw values. This can't overflow our huge
 377                  * buffer because we don't have enough valid entries to get anywhere close. */
 378                 for (j = 1, *cp = '\0'; j <= nno->saw_len; j++) {
 379                         struct name_num_item *nni;
 380                         for (nni = nno->list; nni->name; nni++) {
 381                                 if (nno->saw[nni->num] == j) {
 382                                         *cp++ = ' ';
 383                                         cp += strlcpy(cp, nni->name, MAX_NSTR_STRLEN - (cp - tmpbuf));
 384                                         break;
 385                                 }
 386                         }
 387                 }
 388                 if (!*tmpbuf)
 389                         strlcpy(cp, " INVALID", MAX_NSTR_STRLEN);
 390                 rprintf(FERROR, "%s list:%s\n", am_server ? "Server" : "Client", tmpbuf);
 391         }
 392
 393         exit_cleanup(RERR_UNSUPPORTED);
 394 }
 395
 396 static const char *getenv_nstr(int ntype)
 397 {
 398         const char *env_str = getenv(ntype == NSTR_COMPRESS ? "RSYNC_COMPRESS_LIST" : "RSYNC_CHECKSUM_LIST");
 399
 400         /* When writing a batch file, we always negotiate an old-style choice. */
 401         if (write_batch)
 402                 env_str = ntype == NSTR_COMPRESS ? "zlib" : protocol_version >= 30 ? "md5" : "md4";
 403
 404         if (am_server && env_str) {
 405                 char *cp = strchr(env_str, '&');
 406                 if (cp)
 407                         env_str = cp + 1;
 408         }
 409
 410         return env_str;
 411 }
 412
 413 void validate_choice_vs_env(int ntype, int num1, int num2)
 414 {
 415         struct name_num_obj *nno = ntype == NSTR_COMPRESS ? &valid_compressions : &valid_checksums;
 416         const char *list_str = getenv_nstr(ntype);
 417         char tmpbuf[MAX_NSTR_STRLEN];
 418
 419         if (!list_str)
 420                 return;
 421
 422         while (isSpace(list_str)) list_str++;
 423
 424         if (!*list_str)
 425                 return;
 426
 427         init_nno_saw(nno, 0);
 428         parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 429
 430         if (ntype == NSTR_CHECKSUM) /* If "md4" is in the env list, all the old MD4 choices are OK too. */
 431                 nno->saw[CSUM_MD4_ARCHAIC] = nno->saw[CSUM_MD4_BUSTED] = nno->saw[CSUM_MD4_OLD] = nno->saw[CSUM_MD4];
 432
 433         if (!nno->saw[num1] || (num2 >= 0 && !nno->saw[num2])) {
 434                 rprintf(FERROR, "Your --%s-choice value (%s) was refused by the server.\n",
 435                         ntype == NSTR_COMPRESS ? "compress" : "checksum",
 436                         ntype == NSTR_COMPRESS ? compress_choice : checksum_choice);
 437                 exit_cleanup(RERR_UNSUPPORTED);
 438         }
 439
 440         free(nno->saw);
 441         nno->saw = NULL;
 442 }
 443
 444 /* The saw buffer is initialized and used to store ordinal values from 1 to N
 445  * for the order of the args in the array.  If dup_markup == '\0', duplicates
 446  * are removed otherwise the char is prefixed to the duplicate term and, if it
 447  * is an opening paren/bracket/brace, the matching closing char is suffixed.
 448  * "none" is removed on the client side unless dup_markup != '\0'. */
 449 int get_default_nno_list(struct name_num_obj *nno, char *to_buf, int to_buf_len, char dup_markup)
 450 {
 451         struct name_num_item *nni;
 452         int len = 0, cnt = 0;
 453         char delim = '\0', post_delim;
 454
 455         switch (dup_markup) {
 456         case '(': post_delim = ')'; break;
 457         case '[': post_delim = ']'; break;
 458         case '{': post_delim = '}'; break;
 459         default: post_delim = '\0'; break;
 460         }
 461
 462         init_nno_saw(nno, 0);
 463
 464         for (nni = nno->list, len = 0; nni->name; nni++) {
 465                 if (nni->main_name) {
 466                         if (!dup_markup)
 467                                 continue;
 468                         delim = dup_markup;
 469                 }
 470                 if (nni->num == 0 && !am_server && !dup_markup)
 471                         continue;
 472                 if (len)
 473                         to_buf[len++]= ' ';
 474                 if (delim) {
 475                         to_buf[len++]= delim;
 476                         delim = post_delim;
 477                 }
 478                 len += strlcpy(to_buf+len, nni->name, to_buf_len - len);
 479                 if (len >= to_buf_len - 3)
 480                         exit_cleanup(RERR_UNSUPPORTED); /* IMPOSSIBLE... */
 481                 if (delim) {
 482                         to_buf[len++]= delim;
 483                         delim = '\0';
 484                 }
 485                 nno->saw[nni->num] = ++cnt;
 486         }
 487
 488         return len;
 489 }
 490
 491 static void send_negotiate_str(int f_out, struct name_num_obj *nno, int ntype)
 492 {
 493         char tmpbuf[MAX_NSTR_STRLEN];
 494         const char *list_str = getenv_nstr(ntype);
 495         int len;
 496
 497         if (list_str && *list_str) {
 498                 init_nno_saw(nno, 0);
 499                 len = parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
 500                 list_str = tmpbuf;
 501         } else
 502                 list_str = NULL;
 503
 504         if (!list_str || !*list_str)
 505                 len = get_default_nno_list(nno, tmpbuf, MAX_NSTR_STRLEN, '\0');
 506
 507         if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
 508                 if (am_server)
 509                         rprintf(FINFO, "Server %s list (on server): %s\n", nno->type, tmpbuf);
 510                 else
 511                         rprintf(FINFO, "Client %s list (on client): %s\n", nno->type, tmpbuf);
 512         }
 513
 514         /* Each side sends their list of valid names to the other side and then both sides
 515          * pick the first name in the client's list that is also in the server's list. */
 516         if (do_negotiated_strings)
 517                 write_vstring(f_out, tmpbuf, len);
 518 }
 519
 520 static void negotiate_the_strings(int f_in, int f_out)
 521 {
 522         /* We send all the negotiation strings before we start to read them to help avoid a slow startup. */
 523
 524         if (!checksum_choice)
 525                 send_negotiate_str(f_out, &valid_checksums, NSTR_CHECKSUM);
 526
 527         if (do_compression && !compress_choice)
 528                 send_negotiate_str(f_out, &valid_compressions, NSTR_COMPRESS);
 529
 530         if (valid_checksums.saw) {
 531                 char tmpbuf[MAX_NSTR_STRLEN];
 532                 int len;
 533                 if (do_negotiated_strings)
 534                         len = -1;
 535                 else
 536                         len = strlcpy(tmpbuf, protocol_version >= 30 ? "md5" : "md4", MAX_NSTR_STRLEN);
 537                 recv_negotiate_str(f_in, &valid_checksums, tmpbuf, len);
 538         }
 539
 540         if (valid_compressions.saw) {
 541                 char tmpbuf[MAX_NSTR_STRLEN];
 542                 int len;
 543                 if (do_negotiated_strings)
 544                         len = -1;
 545                 else
 546                         len = strlcpy(tmpbuf, "zlib", MAX_NSTR_STRLEN);
 547                 recv_negotiate_str(f_in, &valid_compressions, tmpbuf, len);
 548         }
 549
 550         /* If the other side is too old to negotiate, the above steps just made sure that
 551          * the env didn't disallow the old algorithm. Mark things as non-negotiated. */
 552         if (!do_negotiated_strings)
 553                 valid_checksums.negotiated_name = valid_compressions.negotiated_name = NULL;
 554 }
 555
 556 void setup_protocol(int f_out,int f_in)
 557 {
 558         assert(file_extra_cnt == 0);
 559         assert(EXTRA64_CNT == 2 || EXTRA64_CNT == 1);
 560
 561         /* All int64 values must be set first so that they are guaranteed to be
 562          * aligned for direct int64-pointer memory access. */
 563         if (preserve_atimes)
 564                 atimes_ndx = (file_extra_cnt += EXTRA64_CNT);
 565         if (preserve_crtimes)
 566                 crtimes_ndx = (file_extra_cnt += EXTRA64_CNT);
 567         if (am_sender) /* This is most likely in the file_extras64 union as well. */
 568                 pathname_ndx = (file_extra_cnt += PTR_EXTRA_CNT);
 569         else
 570                 depth_ndx = ++file_extra_cnt;
 571         if (preserve_uid)
 572                 uid_ndx = ++file_extra_cnt;
 573         if (preserve_gid)
 574                 gid_ndx = ++file_extra_cnt;
 575         if (preserve_acls && !am_sender)
 576                 acls_ndx = ++file_extra_cnt;
 577         if (preserve_xattrs)
 578                 xattrs_ndx = ++file_extra_cnt;
 579
 580         if (am_server)
 581                 set_allow_inc_recurse();
 582
 583         if (remote_protocol == 0) {
 584                 if (am_server && !local_server)
 585                         check_sub_protocol();
 586                 if (!read_batch)
 587                         write_int(f_out, protocol_version);
 588                 remote_protocol = read_int(f_in);
 589                 if (protocol_version > remote_protocol)
 590                         protocol_version = remote_protocol;
 591         }
 592         if (read_batch && remote_protocol > protocol_version) {
 593                 rprintf(FERROR, "The protocol version in the batch file is too new (%d > %d).\n",
 594                         remote_protocol, protocol_version);
 595                 exit_cleanup(RERR_PROTOCOL);
 596         }
 597
 598         if (DEBUG_GTE(PROTO, 1)) {
 599                 rprintf(FINFO, "(%s) Protocol versions: remote=%d, negotiated=%d\n",
 600                         am_server? "Server" : "Client", remote_protocol, protocol_version);
 601         }
 602         if (remote_protocol < MIN_PROTOCOL_VERSION
 603          || remote_protocol > MAX_PROTOCOL_VERSION) {
 604                 rprintf(FERROR,"protocol version mismatch -- is your shell clean?\n");
 605                 rprintf(FERROR,"(see the rsync man page for an explanation)\n");
 606                 exit_cleanup(RERR_PROTOCOL);
 607         }
 608         if (remote_protocol < OLD_PROTOCOL_VERSION) {
 609                 rprintf(FINFO,"%s is very old version of rsync, upgrade recommended.\n",
 610                         am_server? "Client" : "Server");
 611         }
 612         if (protocol_version < MIN_PROTOCOL_VERSION) {
 613                 rprintf(FERROR, "--protocol must be at least %d on the %s.\n",
 614                         MIN_PROTOCOL_VERSION, am_server? "Server" : "Client");
 615                 exit_cleanup(RERR_PROTOCOL);
 616         }
 617         if (protocol_version > PROTOCOL_VERSION) {
 618                 rprintf(FERROR, "--protocol must be no more than %d on the %s.\n",
 619                         PROTOCOL_VERSION, am_server? "Server" : "Client");
 620                 exit_cleanup(RERR_PROTOCOL);
 621         }
 622         if (read_batch)
 623                 check_batch_flags();
 624
 625 #ifndef SUPPORT_PREALLOCATION
 626         if (preallocate_files && !am_sender) {
 627                 rprintf(FERROR, "preallocation is not supported on this %s\n",
 628                         am_server ? "Server" : "Client");
 629                 exit_cleanup(RERR_SYNTAX);
 630         }
 631 #endif
 632
 633         if (protocol_version < 30) {
 634                 if (append_mode == 1)
 635                         append_mode = 2;
 636                 if (preserve_acls && !local_server) {
 637                         rprintf(FERROR,
 638                                 "--acls requires protocol 30 or higher"
 639                                 " (negotiated %d).\n",
 640                                 protocol_version);
 641                         exit_cleanup(RERR_PROTOCOL);
 642                 }
 643                 if (preserve_xattrs && !local_server) {
 644                         rprintf(FERROR,
 645                                 "--xattrs requires protocol 30 or higher"
 646                                 " (negotiated %d).\n",
 647                                 protocol_version);
 648                         exit_cleanup(RERR_PROTOCOL);
 649                 }
 650         }
 651
 652         if (delete_mode && !(delete_before+delete_during+delete_after)) {
 653                 if (protocol_version < 30)
 654                         delete_before = 1;
 655                 else
 656                         delete_during = 1;
 657         }
 658
 659         if (protocol_version < 29) {
 660                 if (fuzzy_basis) {
 661                         rprintf(FERROR,
 662                                 "--fuzzy requires protocol 29 or higher"
 663                                 " (negotiated %d).\n",
 664                                 protocol_version);
 665                         exit_cleanup(RERR_PROTOCOL);
 666                 }
 667
 668                 if (basis_dir_cnt && inplace) {
 669                         rprintf(FERROR,
 670                                 "%s with --inplace requires protocol 29 or higher"
 671                                 " (negotiated %d).\n",
 672                                 alt_dest_opt(0), protocol_version);
 673                         exit_cleanup(RERR_PROTOCOL);
 674                 }
 675
 676                 if (basis_dir_cnt > 1) {
 677                         rprintf(FERROR,
 678                                 "Using more than one %s option requires protocol"
 679                                 " 29 or higher (negotiated %d).\n",
 680                                 alt_dest_opt(0), protocol_version);
 681                         exit_cleanup(RERR_PROTOCOL);
 682                 }
 683
 684                 if (prune_empty_dirs) {
 685                         rprintf(FERROR,
 686                                 "--prune-empty-dirs requires protocol 29 or higher"
 687                                 " (negotiated %d).\n",
 688                                 protocol_version);
 689                         exit_cleanup(RERR_PROTOCOL);
 690                 }
 691         } else if (protocol_version >= 30) {
 692                 if (am_server) {
 693                         compat_flags = allow_inc_recurse ? CF_INC_RECURSE : 0;
 694 #ifdef CAN_SET_SYMLINK_TIMES
 695                         compat_flags |= CF_SYMLINK_TIMES;
 696 #endif
 697 #ifdef ICONV_OPTION
 698                         compat_flags |= CF_SYMLINK_ICONV;
 699 #endif
 700                         if (strchr(client_info, 'f') != NULL)
 701                                 compat_flags |= CF_SAFE_FLIST;
 702                         if (strchr(client_info, 'x') != NULL)
 703                                 compat_flags |= CF_AVOID_XATTR_OPTIM;
 704                         if (strchr(client_info, 'C') != NULL)
 705                                 compat_flags |= CF_CHKSUM_SEED_FIX;
 706                         if (strchr(client_info, 'I') != NULL)
 707                                 compat_flags |= CF_INPLACE_PARTIAL_DIR;
 708                         if (strchr(client_info, 'u') != NULL)
 709                                 compat_flags |= CF_ID0_NAMES;
 710                         if (strchr(client_info, 'v') != NULL) {
 711                                 do_negotiated_strings = 1;
 712                                 compat_flags |= CF_VARINT_FLIST_FLAGS;
 713                         }
 714                         if (strchr(client_info, 'V') != NULL) { /* Support a pre-release 'V' that got superseded */
 715                                 if (!write_batch)
 716                                         compat_flags |= CF_VARINT_FLIST_FLAGS;
 717                                 write_byte(f_out, compat_flags);
 718                         } else
 719                                 write_varint(f_out, compat_flags);
 720                 } else { /* read_varint() is compatible with the older write_byte() when the 0x80 bit isn't on. */
 721                         compat_flags = read_varint(f_in);
 722                         if  (compat_flags & CF_VARINT_FLIST_FLAGS)
 723                                 do_negotiated_strings = 1;
 724                 }
 725                 /* The inc_recurse var MUST be set to 0 or 1. */
 726                 inc_recurse = compat_flags & CF_INC_RECURSE ? 1 : 0;
 727                 want_xattr_optim = protocol_version >= 31 && !(compat_flags & CF_AVOID_XATTR_OPTIM);
 728                 proper_seed_order = compat_flags & CF_CHKSUM_SEED_FIX ? 1 : 0;
 729                 xfer_flags_as_varint = compat_flags & CF_VARINT_FLIST_FLAGS ? 1 : 0;
 730                 xmit_id0_names = compat_flags & CF_ID0_NAMES ? 1 : 0;
 731                 if (!xfer_flags_as_varint && preserve_crtimes) {
 732                         fprintf(stderr, "Both rsync versions must be at least 3.2.0 for --crtimes.\n");
 733                         exit_cleanup(RERR_PROTOCOL);
 734                 }
 735                 if (am_sender) {
 736                         receiver_symlink_times = am_server
 737                             ? strchr(client_info, 'L') != NULL
 738                             : !!(compat_flags & CF_SYMLINK_TIMES);
 739                 }
 740 #ifdef CAN_SET_SYMLINK_TIMES
 741                 else
 742                         receiver_symlink_times = 1;
 743 #endif
 744 #ifdef ICONV_OPTION
 745                 sender_symlink_iconv = iconv_opt && (am_server
 746                     ? strchr(client_info, 's') != NULL
 747                     : !!(compat_flags & CF_SYMLINK_ICONV));
 748 #endif
 749                 if (inc_recurse && !allow_inc_recurse) {
 750                         /* This should only be able to happen in a batch. */
 751                         fprintf(stderr,
 752                                 "Incompatible options specified for inc-recursive %s.\n",
 753                                 read_batch ? "batch file" : "connection");
 754                         exit_cleanup(RERR_SYNTAX);
 755                 }
 756                 use_safe_inc_flist = (compat_flags & CF_SAFE_FLIST) || protocol_version >= 31;
 757                 need_messages_from_generator = 1;
 758                 if (compat_flags & CF_INPLACE_PARTIAL_DIR)
 759                         inplace_partial = 1;
 760 #ifdef CAN_SET_SYMLINK_TIMES
 761         } else if (!am_sender) {
 762                 receiver_symlink_times = 1;
 763 #endif
 764         }
 765
 766         if (read_batch)
 767                 do_negotiated_strings = 0;
 768
 769         if (need_unsorted_flist && (!am_sender || inc_recurse))
 770                 unsort_ndx = ++file_extra_cnt;
 771
 772         if (partial_dir && *partial_dir != '/' && (!am_server || local_server)) {
 773                 int rflags = FILTRULE_NO_PREFIXES | FILTRULE_DIRECTORY;
 774                 if (!am_sender || protocol_version >= 30)
 775                         rflags |= FILTRULE_PERISHABLE;
 776                 parse_filter_str(&filter_list, partial_dir, rule_template(rflags), 0);
 777         }
 778
 779
 780 #ifdef ICONV_OPTION
 781         if (protect_args && files_from) {
 782                 if (am_sender)
 783                         filesfrom_convert = filesfrom_host && ic_send != (iconv_t)-1;
 784                 else
 785                         filesfrom_convert = !filesfrom_host && ic_recv != (iconv_t)-1;
 786         }
 787 #endif
 788
 789         negotiate_the_strings(f_in, f_out);
 790
 791         if (am_server) {
 792                 if (!checksum_seed)
 793                         checksum_seed = time(NULL) ^ (getpid() << 6);
 794                 write_int(f_out, checksum_seed);
 795         } else {
 796                 checksum_seed = read_int(f_in);
 797         }
 798
 799         parse_checksum_choice(1); /* Sets checksum_type & xfersum_type */
 800         parse_compress_choice(1); /* Sets do_compression */
 801
 802         if (write_batch && !am_server)
 803                 write_batch_shell_file();
 804
 805         init_flist();
 806 }