xattrs.c

   1 /*
   2  * Extended Attribute support for rsync.
   3  * Written by Jay Fenlason, vaguely based on the ACLs patch.
   4  *
   5  * Copyright (C) 2004 Red Hat, Inc.
   6  * Copyright (C) 2006-2008 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 "ifuncs.h"
  24 #include "lib/sysxattrs.h"
  25
  26 #ifdef SUPPORT_XATTRS
  27
  28 extern int dry_run;
  29 extern int am_root;
  30 extern int am_sender;
  31 extern int am_generator;
  32 extern int read_only;
  33 extern int list_only;
  34 extern int preserve_xattrs;
  35 extern int checksum_seed;
  36
  37 #define RSYNC_XAL_INITIAL 5
  38 #define RSYNC_XAL_LIST_INITIAL 100
  39
  40 #define MAX_FULL_DATUM 32
  41
  42 #define HAS_PREFIX(str, prfx) (*(str) == *(prfx) \
  43                             && strncmp(str, prfx, sizeof (prfx) - 1) == 0)
  44
  45 #define XATTR_ABBREV(x) ((size_t)((x).name - (x).datum) < (x).datum_len)
  46
  47 #define XSTATE_ABBREV   1
  48 #define XSTATE_DONE     2
  49 #define XSTATE_TODO     3
  50
  51 #define USER_PREFIX "user."
  52 #define UPRE_LEN ((int)sizeof USER_PREFIX - 1)
  53 #define SYSTEM_PREFIX "system."
  54 #define SPRE_LEN ((int)sizeof SYSTEM_PREFIX - 1)
  55
  56 #ifdef HAVE_LINUX_XATTRS
  57 #define MIGHT_NEED_RPRE (am_root < 0)
  58 #define RSYNC_PREFIX USER_PREFIX "rsync."
  59 #else
  60 #define MIGHT_NEED_RPRE am_root
  61 #define RSYNC_PREFIX "rsync."
  62 #endif
  63 #define RPRE_LEN ((int)sizeof RSYNC_PREFIX - 1)
  64
  65 #define XSTAT_SUFFIX "stat"
  66 #define XSTAT_ATTR RSYNC_PREFIX "%" XSTAT_SUFFIX
  67 #define XACC_ACL_SUFFIX "aacl"
  68 #define XACC_ACL_ATTR RSYNC_PREFIX "%" XACC_ACL_SUFFIX
  69 #define XDEF_ACL_SUFFIX "dacl"
  70 #define XDEF_ACL_ATTR RSYNC_PREFIX "%" XDEF_ACL_SUFFIX
  71
  72 typedef struct {
  73         char *datum, *name;
  74         size_t datum_len, name_len;
  75         int num;
  76 } rsync_xa;
  77
  78 static size_t namebuf_len = 0;
  79 static char *namebuf = NULL;
  80
  81 static item_list empty_xattr = EMPTY_ITEM_LIST;
  82 static item_list rsync_xal_l = EMPTY_ITEM_LIST;
  83
  84 /* ------------------------------------------------------------------------- */
  85
  86 static void rsync_xal_free(item_list *xalp)
  87 {
  88         size_t i;
  89         rsync_xa *rxas = xalp->items;
  90
  91         for (i = 0; i < xalp->count; i++) {
  92                 free(rxas[i].datum);
  93                 /*free(rxas[i].name);*/
  94         }
  95         xalp->count = 0;
  96 }
  97
  98 void free_xattr(stat_x *sxp)
  99 {
 100         if (!sxp->xattr)
 101                 return;
 102         rsync_xal_free(sxp->xattr);
 103         free(sxp->xattr);
 104         sxp->xattr = NULL;
 105 }
 106
 107 static int rsync_xal_compare_names(const void *x1, const void *x2)
 108 {
 109         const rsync_xa *xa1 = x1;
 110         const rsync_xa *xa2 = x2;
 111         return strcmp(xa1->name, xa2->name);
 112 }
 113
 114 static ssize_t get_xattr_names(const char *fname)
 115 {
 116         ssize_t list_len;
 117         double arg;
 118
 119         if (!namebuf) {
 120                 namebuf_len = 1024;
 121                 namebuf = new_array(char, namebuf_len);
 122                 if (!namebuf)
 123                         out_of_memory("get_xattr_names");
 124         }
 125
 126         while (1) {
 127                 /* The length returned includes all the '\0' terminators. */
 128                 list_len = sys_llistxattr(fname, namebuf, namebuf_len);
 129                 if (list_len >= 0) {
 130                         if ((size_t)list_len <= namebuf_len)
 131                                 break;
 132                 } else if (errno == ENOTSUP)
 133                         return 0;
 134                 else if (errno != ERANGE) {
 135                         arg = (double)namebuf_len;
 136                   got_error:
 137                         rsyserr(FERROR_XFER, errno,
 138                                 "get_xattr_names: llistxattr(\"%s\",%.0f) failed",
 139                                 fname, arg);
 140                         return -1;
 141                 }
 142                 list_len = sys_llistxattr(fname, NULL, 0);
 143                 if (list_len < 0) {
 144                         arg = 0;
 145                         goto got_error;
 146                 }
 147                 if (namebuf_len)
 148                         free(namebuf);
 149                 namebuf_len = list_len + 1024;
 150                 namebuf = new_array(char, namebuf_len);
 151                 if (!namebuf)
 152                         out_of_memory("get_xattr_names");
 153         }
 154
 155         return list_len;
 156 }
 157
 158 /* On entry, the *len_ptr parameter contains the size of the extra space we
 159  * should allocate when we create a buffer for the data.  On exit, it contains
 160  * the length of the datum. */
 161 static char *get_xattr_data(const char *fname, const char *name, size_t *len_ptr,
 162                             int no_missing_error)
 163 {
 164         size_t datum_len = sys_lgetxattr(fname, name, NULL, 0);
 165         size_t extra_len = *len_ptr;
 166         char *ptr;
 167
 168         *len_ptr = datum_len;
 169
 170         if (datum_len == (size_t)-1) {
 171                 if (errno == ENOTSUP || no_missing_error)
 172                         return NULL;
 173                 rsyserr(FERROR_XFER, errno,
 174                         "get_xattr_data: lgetxattr(\"%s\",\"%s\",0) failed",
 175                         fname, name);
 176                 return NULL;
 177         }
 178
 179         if (!datum_len && !extra_len)
 180                 extra_len = 1; /* request non-zero amount of memory */
 181         if (datum_len + extra_len < datum_len)
 182                 overflow_exit("get_xattr_data");
 183         if (!(ptr = new_array(char, datum_len + extra_len)))
 184                 out_of_memory("get_xattr_data");
 185
 186         if (datum_len) {
 187                 size_t len = sys_lgetxattr(fname, name, ptr, datum_len);
 188                 if (len != datum_len) {
 189                         if (len == (size_t)-1) {
 190                                 rsyserr(FERROR_XFER, errno,
 191                                     "get_xattr_data: lgetxattr(\"%s\",\"%s\",%ld)"
 192                                     " failed", fname, name, (long)datum_len);
 193                         } else {
 194                                 rprintf(FERROR_XFER,
 195                                     "get_xattr_data: lgetxattr(\"%s\",\"%s\",%ld)"
 196                                     " returned %ld\n", fname, name,
 197                                     (long)datum_len, (long)len);
 198                         }
 199                         free(ptr);
 200                         return NULL;
 201                 }
 202         }
 203
 204         return ptr;
 205 }
 206
 207 static int rsync_xal_get(const char *fname, item_list *xalp)
 208 {
 209         ssize_t list_len, name_len;
 210         size_t datum_len, name_offset;
 211         char *name, *ptr;
 212 #ifdef HAVE_LINUX_XATTRS
 213         int user_only = am_sender ? 0 : !am_root;
 214 #endif
 215         rsync_xa *rxa;
 216         int count;
 217
 218         /* This puts the name list into the "namebuf" buffer. */
 219         if ((list_len = get_xattr_names(fname)) < 0)
 220                 return -1;
 221
 222         for (name = namebuf; list_len > 0; name += name_len) {
 223                 name_len = strlen(name) + 1;
 224                 list_len -= name_len;
 225
 226 #ifdef HAVE_LINUX_XATTRS
 227                 /* We always ignore the system namespace, and non-root
 228                  * ignores everything but the user namespace. */
 229                 if (user_only ? !HAS_PREFIX(name, USER_PREFIX)
 230                               : HAS_PREFIX(name, SYSTEM_PREFIX))
 231                         continue;
 232 #endif
 233
 234                 /* No rsync.%FOO attributes are copied w/o 2 -X options. */
 235                 if (name_len > RPRE_LEN && name[RPRE_LEN] == '%'
 236                  && HAS_PREFIX(name, RSYNC_PREFIX)) {
 237                         if ((am_sender && preserve_xattrs < 2)
 238                          || (am_root < 0
 239                           && (strcmp(name+RPRE_LEN+1, XSTAT_SUFFIX) == 0
 240                            || strcmp(name+RPRE_LEN+1, XACC_ACL_SUFFIX) == 0
 241                            || strcmp(name+RPRE_LEN+1, XDEF_ACL_SUFFIX) == 0)))
 242                                 continue;
 243                 }
 244
 245                 datum_len = name_len; /* Pass extra size to get_xattr_data() */
 246                 if (!(ptr = get_xattr_data(fname, name, &datum_len, 0)))
 247                         return -1;
 248
 249                 if (datum_len > MAX_FULL_DATUM) {
 250                         /* For large datums, we store a flag and a checksum. */
 251                         name_offset = 1 + MAX_DIGEST_LEN;
 252                         sum_init(checksum_seed);
 253                         sum_update(ptr, datum_len);
 254                         free(ptr);
 255
 256                         if (!(ptr = new_array(char, name_offset + name_len)))
 257                                 out_of_memory("rsync_xal_get");
 258                         *ptr = XSTATE_ABBREV;
 259                         sum_end(ptr + 1);
 260                 } else
 261                         name_offset = datum_len;
 262
 263                 rxa = EXPAND_ITEM_LIST(xalp, rsync_xa, RSYNC_XAL_INITIAL);
 264                 rxa->name = ptr + name_offset;
 265                 memcpy(rxa->name, name, name_len);
 266                 rxa->datum = ptr;
 267                 rxa->name_len = name_len;
 268                 rxa->datum_len = datum_len;
 269         }
 270         count = xalp->count;
 271         rxa = xalp->items;
 272         if (count > 1)
 273                 qsort(rxa, count, sizeof (rsync_xa), rsync_xal_compare_names);
 274         for (rxa += count-1; count; count--, rxa--)
 275                 rxa->num = count;
 276         return 0;
 277 }
 278
 279 /* Read the xattr(s) for this filename. */
 280 int get_xattr(const char *fname, stat_x *sxp)
 281 {
 282         sxp->xattr = new(item_list);
 283         *sxp->xattr = empty_xattr;
 284         if (rsync_xal_get(fname, sxp->xattr) < 0) {
 285                 free_xattr(sxp);
 286                 return -1;
 287         }
 288         return 0;
 289 }
 290
 291 int copy_xattrs(const char *source, const char *dest)
 292 {
 293         ssize_t list_len, name_len;
 294         size_t datum_len;
 295         char *name, *ptr;
 296 #ifdef HAVE_LINUX_XATTRS
 297         int user_only = am_sender ? 0 : !am_root;
 298 #endif
 299
 300         /* This puts the name list into the "namebuf" buffer. */
 301         if ((list_len = get_xattr_names(source)) < 0)
 302                 return -1;
 303
 304         for (name = namebuf; list_len > 0; name += name_len) {
 305                 name_len = strlen(name) + 1;
 306                 list_len -= name_len;
 307
 308 #ifdef HAVE_LINUX_XATTRS
 309                 /* We always ignore the system namespace, and non-root
 310                  * ignores everything but the user namespace. */
 311                 if (user_only ? !HAS_PREFIX(name, USER_PREFIX)
 312                               : HAS_PREFIX(name, SYSTEM_PREFIX))
 313                         continue;
 314 #endif
 315
 316                 datum_len = 0;
 317                 if (!(ptr = get_xattr_data(source, name, &datum_len, 0)))
 318                         return -1;
 319                 if (sys_lsetxattr(dest, name, ptr, datum_len) < 0) {
 320                         int save_errno = errno ? errno : EINVAL;
 321                         rsyserr(FERROR_XFER, errno,
 322                                 "rsync_xal_set: lsetxattr(\"%s\",\"%s\") failed",
 323                                 dest, name);
 324                         errno = save_errno;
 325                         return -1;
 326                 }
 327                 free(ptr);
 328         }
 329
 330         return 0;
 331 }
 332
 333 static int find_matching_xattr(item_list *xalp)
 334 {
 335         size_t i, j;
 336         item_list *lst = rsync_xal_l.items;
 337
 338         for (i = 0; i < rsync_xal_l.count; i++) {
 339                 rsync_xa *rxas1 = lst[i].items;
 340                 rsync_xa *rxas2 = xalp->items;
 341
 342                 /* Wrong number of elements? */
 343                 if (lst[i].count != xalp->count)
 344                         continue;
 345                 /* any elements different? */
 346                 for (j = 0; j < xalp->count; j++) {
 347                         if (rxas1[j].name_len != rxas2[j].name_len
 348                          || rxas1[j].datum_len != rxas2[j].datum_len
 349                          || strcmp(rxas1[j].name, rxas2[j].name))
 350                                 break;
 351                         if (rxas1[j].datum_len > MAX_FULL_DATUM) {
 352                                 if (memcmp(rxas1[j].datum + 1,
 353                                            rxas2[j].datum + 1,
 354                                            MAX_DIGEST_LEN) != 0)
 355                                         break;
 356                         } else {
 357                                 if (memcmp(rxas1[j].datum, rxas2[j].datum,
 358                                            rxas2[j].datum_len))
 359                                         break;
 360                         }
 361                 }
 362                 /* no differences found.  This is The One! */
 363                 if (j == xalp->count)
 364                         return i;
 365         }
 366
 367         return -1;
 368 }
 369
 370 /* Store *xalp on the end of rsync_xal_l */
 371 static void rsync_xal_store(item_list *xalp)
 372 {
 373         item_list *new_lst = EXPAND_ITEM_LIST(&rsync_xal_l, item_list, RSYNC_XAL_LIST_INITIAL);
 374         /* Since the following call starts a new list, we know it will hold the
 375          * entire initial-count, not just enough space for one new item. */
 376         *new_lst = empty_xattr;
 377         (void)EXPAND_ITEM_LIST(new_lst, rsync_xa, xalp->count);
 378         memcpy(new_lst->items, xalp->items, xalp->count * sizeof (rsync_xa));
 379         new_lst->count = xalp->count;
 380         xalp->count = 0;
 381 }
 382
 383 /* Send the make_xattr()-generated xattr list for this flist entry. */
 384 int send_xattr(stat_x *sxp, int f)
 385 {
 386         int ndx = find_matching_xattr(sxp->xattr);
 387
 388         /* Send 0 (-1 + 1) to indicate that literal xattr data follows. */
 389         write_varint(f, ndx + 1);
 390
 391         if (ndx < 0) {
 392                 rsync_xa *rxa;
 393                 int count = sxp->xattr->count;
 394                 write_varint(f, count);
 395                 for (rxa = sxp->xattr->items; count--; rxa++) {
 396                         size_t name_len = rxa->name_len;
 397                         const char *name = rxa->name;
 398                         /* Strip the rsync prefix from disguised namespaces. */
 399                         if (name_len > RPRE_LEN
 400 #ifdef HAVE_LINUX_XATTRS
 401                          && am_root < 0
 402 #endif
 403                          && name[RPRE_LEN] != '%' && HAS_PREFIX(name, RSYNC_PREFIX)) {
 404                                 name += RPRE_LEN;
 405                                 name_len -= RPRE_LEN;
 406                         }
 407 #ifndef HAVE_LINUX_XATTRS
 408                         else {
 409                                 /* Put everything else in the user namespace. */
 410                                 name_len += UPRE_LEN;
 411                         }
 412 #endif
 413                         write_varint(f, name_len);
 414                         write_varint(f, rxa->datum_len);
 415 #ifndef HAVE_LINUX_XATTRS
 416                         if (name_len > rxa->name_len) {
 417                                 write_buf(f, USER_PREFIX, UPRE_LEN);
 418                                 name_len -= UPRE_LEN;
 419                         }
 420 #endif
 421                         write_buf(f, name, name_len);
 422                         if (rxa->datum_len > MAX_FULL_DATUM)
 423                                 write_buf(f, rxa->datum + 1, MAX_DIGEST_LEN);
 424                         else
 425                                 write_buf(f, rxa->datum, rxa->datum_len);
 426                 }
 427                 ndx = rsync_xal_l.count; /* pre-incremented count */
 428                 rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
 429         }
 430
 431         return ndx;
 432 }
 433
 434 /* Return a flag indicating if we need to change a file's xattrs.  If
 435  * "find_all" is specified, also mark any abbreviated xattrs that we
 436  * need so that send_xattr_request() can tell the sender about them. */
 437 int xattr_diff(struct file_struct *file, stat_x *sxp, int find_all)
 438 {
 439         item_list *lst = rsync_xal_l.items;
 440         rsync_xa *snd_rxa, *rec_rxa;
 441         int snd_cnt, rec_cnt;
 442         int cmp, same, xattrs_equal = 1;
 443
 444         if (sxp && XATTR_READY(*sxp)) {
 445                 rec_rxa = sxp->xattr->items;
 446                 rec_cnt = sxp->xattr->count;
 447         } else {
 448                 rec_rxa = NULL;
 449                 rec_cnt = 0;
 450         }
 451
 452         if (F_XATTR(file) >= 0)
 453                 lst += F_XATTR(file);
 454         else
 455                 lst = &empty_xattr;
 456
 457         snd_rxa = lst->items;
 458         snd_cnt = lst->count;
 459
 460         /* If the count of the sender's xattrs is different from our
 461          * (receiver's) xattrs, the lists are not the same. */
 462         if (snd_cnt != rec_cnt) {
 463                 if (!find_all)
 464                         return 1;
 465                 xattrs_equal = 0;
 466         }
 467
 468         while (snd_cnt) {
 469                 cmp = rec_cnt ? strcmp(snd_rxa->name, rec_rxa->name) : -1;
 470                 if (cmp > 0)
 471                         same = 0;
 472                 else if (snd_rxa->datum_len > MAX_FULL_DATUM) {
 473                         same = cmp == 0 && snd_rxa->datum_len == rec_rxa->datum_len
 474                             && memcmp(snd_rxa->datum + 1, rec_rxa->datum + 1,
 475                                       MAX_DIGEST_LEN) == 0;
 476                         /* Flag unrequested items that we need. */
 477                         if (!same && find_all && snd_rxa->datum[0] == XSTATE_ABBREV)
 478                                 snd_rxa->datum[0] = XSTATE_TODO;
 479                 } else {
 480                         same = cmp == 0 && snd_rxa->datum_len == rec_rxa->datum_len
 481                             && memcmp(snd_rxa->datum, rec_rxa->datum,
 482                                       snd_rxa->datum_len) == 0;
 483                 }
 484                 if (!same) {
 485                         if (!find_all)
 486                                 return 1;
 487                         xattrs_equal = 0;
 488                 }
 489
 490                 if (cmp <= 0) {
 491                         snd_rxa++;
 492                         snd_cnt--;
 493                 }
 494                 if (cmp >= 0) {
 495                         rec_rxa++;
 496                         rec_cnt--;
 497                 }
 498         }
 499
 500         if (rec_cnt)
 501                 xattrs_equal = 0;
 502
 503         return !xattrs_equal;
 504 }
 505
 506 /* When called by the generator (with a NULL fname), this tells the sender
 507  * all the abbreviated xattr values we need.  When called by the sender
 508  * (with a non-NULL fname), we send all the extra xattr data it needs.
 509  * The generator may also call with f_out < 0 to just change all the
 510  * XSTATE_ABBREV states into XSTATE_DONE. */
 511 void send_xattr_request(const char *fname, struct file_struct *file, int f_out)
 512 {
 513         item_list *lst = rsync_xal_l.items;
 514         int cnt, prior_req = 0;
 515         rsync_xa *rxa;
 516
 517         lst += F_XATTR(file);
 518         for (rxa = lst->items, cnt = lst->count; cnt--; rxa++) {
 519                 if (rxa->datum_len <= MAX_FULL_DATUM)
 520                         continue;
 521                 switch (rxa->datum[0]) {
 522                 case XSTATE_ABBREV:
 523                         /* Items left abbreviated matched the sender's checksum, so
 524                          * the receiver will cache the local data for future use. */
 525                         if (am_generator)
 526                                 rxa->datum[0] = XSTATE_DONE;
 527                         continue;
 528                 case XSTATE_TODO:
 529                         assert(f_out >= 0);
 530                         break;
 531                 default:
 532                         continue;
 533                 }
 534
 535                 /* Flag that we handled this abbreviated item. */
 536                 rxa->datum[0] = XSTATE_DONE;
 537
 538                 write_varint(f_out, rxa->num - prior_req);
 539                 prior_req = rxa->num;
 540
 541                 if (fname) {
 542                         size_t len = 0;
 543                         char *ptr;
 544
 545                         /* Re-read the long datum. */
 546                         if (!(ptr = get_xattr_data(fname, rxa->name, &len, 0))) {
 547                                 rprintf(FERROR_XFER, "failed to re-read xattr %s for %s\n", rxa->name, fname);
 548                                 write_varint(f_out, 0);
 549                                 continue;
 550                         }
 551
 552                         write_varint(f_out, len); /* length might have changed! */
 553                         write_buf(f_out, ptr, len);
 554                         free(ptr);
 555                 }
 556         }
 557
 558         if (f_out >= 0)
 559                 write_byte(f_out, 0); /* end the list */
 560 }
 561
 562 /* When called by the sender, read the request from the generator and mark
 563  * any needed xattrs with a flag that lets us know they need to be sent to
 564  * the receiver.  When called by the receiver, reads the sent data and
 565  * stores it in place of its checksum. */
 566 int recv_xattr_request(struct file_struct *file, int f_in)
 567 {
 568         item_list *lst = rsync_xal_l.items;
 569         char *old_datum, *name;
 570         rsync_xa *rxa;
 571         int rel_pos, cnt, num, got_xattr_data = 0;
 572
 573         if (F_XATTR(file) < 0) {
 574                 rprintf(FERROR, "recv_xattr_request: internal data error!\n");
 575                 exit_cleanup(RERR_STREAMIO);
 576         }
 577         lst += F_XATTR(file);
 578
 579         cnt = lst->count;
 580         rxa = lst->items;
 581         num = 0;
 582         while ((rel_pos = read_varint(f_in)) != 0) {
 583                 num += rel_pos;
 584                 while (cnt && rxa->num < num) {
 585                     rxa++;
 586                     cnt--;
 587                 }
 588                 if (!cnt || rxa->num != num) {
 589                         rprintf(FERROR, "[%s] could not find xattr #%d for %s\n",
 590                                 who_am_i(), num, f_name(file, NULL));
 591                         exit_cleanup(RERR_STREAMIO);
 592                 }
 593                 if (!XATTR_ABBREV(*rxa) || rxa->datum[0] != XSTATE_ABBREV) {
 594                         rprintf(FERROR, "[%s] internal abbrev error on %s (%s, len=%ld)!\n",
 595                                 who_am_i(), f_name(file, NULL), rxa->name, (long)rxa->datum_len);
 596                         exit_cleanup(RERR_STREAMIO);
 597                 }
 598
 599                 if (am_sender) {
 600                         rxa->datum[0] = XSTATE_TODO;
 601                         continue;
 602                 }
 603
 604                 old_datum = rxa->datum;
 605                 rxa->datum_len = read_varint(f_in);
 606
 607                 if (rxa->name_len + rxa->datum_len < rxa->name_len)
 608                         overflow_exit("recv_xattr_request");
 609                 rxa->datum = new_array(char, rxa->datum_len + rxa->name_len);
 610                 if (!rxa->datum)
 611                         out_of_memory("recv_xattr_request");
 612                 name = rxa->datum + rxa->datum_len;
 613                 memcpy(name, rxa->name, rxa->name_len);
 614                 rxa->name = name;
 615                 free(old_datum);
 616                 read_buf(f_in, rxa->datum, rxa->datum_len);
 617                 got_xattr_data = 1;
 618         }
 619
 620         return got_xattr_data;
 621 }
 622
 623 /* ------------------------------------------------------------------------- */
 624
 625 /* receive and build the rsync_xattr_lists */
 626 void receive_xattr(struct file_struct *file, int f)
 627 {
 628         static item_list temp_xattr = EMPTY_ITEM_LIST;
 629         int count, num;
 630 #ifdef HAVE_LINUX_XATTRS
 631         int need_sort = 0;
 632 #else
 633         int need_sort = 1;
 634 #endif
 635         int ndx = read_varint(f);
 636
 637         if (ndx < 0 || (size_t)ndx > rsync_xal_l.count) {
 638                 rprintf(FERROR, "receive_xattr: xa index %d out of"
 639                         " range for %s\n", ndx, f_name(file, NULL));
 640                 exit_cleanup(RERR_STREAMIO);
 641         }
 642
 643         if (ndx != 0) {
 644                 F_XATTR(file) = ndx - 1;
 645                 return;
 646         }
 647
 648         if ((count = read_varint(f)) != 0) {
 649                 (void)EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, count);
 650                 temp_xattr.count = 0;
 651         }
 652
 653         for (num = 1; num <= count; num++) {
 654                 char *ptr, *name;
 655                 rsync_xa *rxa;
 656                 size_t name_len = read_varint(f);
 657                 size_t datum_len = read_varint(f);
 658                 size_t dget_len = datum_len > MAX_FULL_DATUM ? 1 + MAX_DIGEST_LEN : datum_len;
 659                 size_t extra_len = MIGHT_NEED_RPRE ? RPRE_LEN : 0;
 660                 if ((dget_len + extra_len < dget_len)
 661                  || (dget_len + extra_len + name_len < dget_len))
 662                         overflow_exit("receive_xattr");
 663                 ptr = new_array(char, dget_len + extra_len + name_len);
 664                 if (!ptr)
 665                         out_of_memory("receive_xattr");
 666                 name = ptr + dget_len + extra_len;
 667                 read_buf(f, name, name_len);
 668                 if (dget_len == datum_len)
 669                         read_buf(f, ptr, dget_len);
 670                 else {
 671                         *ptr = XSTATE_ABBREV;
 672                         read_buf(f, ptr + 1, MAX_DIGEST_LEN);
 673                 }
 674 #ifdef HAVE_LINUX_XATTRS
 675                 /* Non-root can only save the user namespace. */
 676                 if (am_root <= 0 && !HAS_PREFIX(name, USER_PREFIX)) {
 677                         if (!am_root) {
 678                                 free(ptr);
 679                                 continue;
 680                         }
 681                         name -= RPRE_LEN;
 682                         name_len += RPRE_LEN;
 683                         memcpy(name, RSYNC_PREFIX, RPRE_LEN);
 684                         need_sort = 1;
 685                 }
 686 #else
 687                 /* This OS only has a user namespace, so we either
 688                  * strip the user prefix, or we put a non-user
 689                  * namespace inside our rsync hierarchy. */
 690                 if (HAS_PREFIX(name, USER_PREFIX)) {
 691                         name += UPRE_LEN;
 692                         name_len -= UPRE_LEN;
 693                 } else if (am_root) {
 694                         name -= RPRE_LEN;
 695                         name_len += RPRE_LEN;
 696                         memcpy(name, RSYNC_PREFIX, RPRE_LEN);
 697                 } else {
 698                         free(ptr);
 699                         continue;
 700                 }
 701 #endif
 702                 /* No rsync.%FOO attributes are copied w/o 2 -X options. */
 703                 if (preserve_xattrs < 2 && name_len > RPRE_LEN
 704                  && name[RPRE_LEN] == '%' && HAS_PREFIX(name, RSYNC_PREFIX)) {
 705                         free(ptr);
 706                         continue;
 707                 }
 708                 rxa = EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, 1);
 709                 rxa->name = name;
 710                 rxa->datum = ptr;
 711                 rxa->name_len = name_len;
 712                 rxa->datum_len = datum_len;
 713                 rxa->num = num;
 714         }
 715
 716         if (need_sort && count > 1)
 717                 qsort(temp_xattr.items, count, sizeof (rsync_xa), rsync_xal_compare_names);
 718
 719         ndx = rsync_xal_l.count; /* pre-incremented count */
 720         rsync_xal_store(&temp_xattr); /* adds item to rsync_xal_l */
 721
 722         F_XATTR(file) = ndx;
 723 }
 724
 725 /* Turn the xattr data in stat_x into cached xattr data, setting the index
 726  * values in the file struct. */
 727 void cache_xattr(struct file_struct *file, stat_x *sxp)
 728 {
 729         int ndx;
 730
 731         if (!sxp->xattr)
 732                 return;
 733
 734         ndx = find_matching_xattr(sxp->xattr);
 735         if (ndx < 0)
 736                 rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
 737
 738         F_XATTR(file) = ndx;
 739 }
 740
 741 static int rsync_xal_set(const char *fname, item_list *xalp,
 742                          const char *fnamecmp, stat_x *sxp)
 743 {
 744         rsync_xa *rxas = xalp->items;
 745         ssize_t list_len;
 746         size_t i, len;
 747         char *name, *ptr, sum[MAX_DIGEST_LEN];
 748         size_t name_len;
 749         int ret = 0;
 750
 751         /* This puts the current name list into the "namebuf" buffer. */
 752         if ((list_len = get_xattr_names(fname)) < 0)
 753                 return -1;
 754
 755         for (i = 0; i < xalp->count; i++) {
 756                 name = rxas[i].name;
 757
 758                 if (XATTR_ABBREV(rxas[i])) {
 759                         /* See if the fnamecmp version is identical. */
 760                         len = name_len = rxas[i].name_len;
 761                         if ((ptr = get_xattr_data(fnamecmp, name, &len, 1)) == NULL) {
 762                           still_abbrev:
 763                                 if (am_generator)
 764                                         continue;
 765                                 rprintf(FERROR, "Missing abbreviated xattr value, %s, for %s\n",
 766                                         rxas[i].name, full_fname(fname));
 767                                 ret = -1;
 768                                 continue;
 769                         }
 770                         if (len != rxas[i].datum_len) {
 771                                 free(ptr);
 772                                 goto still_abbrev;
 773                         }
 774
 775                         sum_init(checksum_seed);
 776                         sum_update(ptr, len);
 777                         sum_end(sum);
 778                         if (memcmp(sum, rxas[i].datum + 1, MAX_DIGEST_LEN) != 0) {
 779                                 free(ptr);
 780                                 goto still_abbrev;
 781                         }
 782
 783                         if (fname == fnamecmp)
 784                                 ; /* Value is already set when identical */
 785                         else if (sys_lsetxattr(fname, name, ptr, len) < 0) {
 786                                 rsyserr(FERROR_XFER, errno,
 787                                         "rsync_xal_set: lsetxattr(\"%s\",\"%s\") failed",
 788                                         fname, name);
 789                                 ret = -1;
 790                         } else /* make sure caller sets mtime */
 791                                 sxp->st.st_mtime = (time_t)-1;
 792
 793                         if (am_generator) { /* generator items stay abbreviated */
 794                                 free(ptr);
 795                                 continue;
 796                         }
 797
 798                         memcpy(ptr + len, name, name_len);
 799                         free(rxas[i].datum);
 800
 801                         rxas[i].name = name = ptr + len;
 802                         rxas[i].datum = ptr;
 803                         continue;
 804                 }
 805
 806                 if (sys_lsetxattr(fname, name, rxas[i].datum, rxas[i].datum_len) < 0) {
 807                         rsyserr(FERROR_XFER, errno,
 808                                 "rsync_xal_set: lsetxattr(\"%s\",\"%s\") failed",
 809                                 fname, name);
 810                         ret = -1;
 811                 } else /* make sure caller sets mtime */
 812                         sxp->st.st_mtime = (time_t)-1;
 813         }
 814
 815         /* Remove any extraneous names. */
 816         for (name = namebuf; list_len > 0; name += name_len) {
 817                 name_len = strlen(name) + 1;
 818                 list_len -= name_len;
 819
 820 #ifdef HAVE_LINUX_XATTRS
 821                 /* We always ignore the system namespace, and non-root
 822                  * ignores everything but the user namespace. */
 823                 if (am_root ? HAS_PREFIX(name, SYSTEM_PREFIX)
 824                             : !HAS_PREFIX(name, USER_PREFIX))
 825                         continue;
 826 #endif
 827                 if (am_root < 0 && name_len > RPRE_LEN
 828                  && name[RPRE_LEN] == '%' && strcmp(name, XSTAT_ATTR) == 0)
 829                         continue;
 830
 831                 for (i = 0; i < xalp->count; i++) {
 832                         if (strcmp(name, rxas[i].name) == 0)
 833                                 break;
 834                 }
 835                 if (i == xalp->count) {
 836                         if (sys_lremovexattr(fname, name) < 0) {
 837                                 rsyserr(FERROR_XFER, errno,
 838                                         "rsync_xal_clear: lremovexattr(\"%s\",\"%s\") failed",
 839                                         fname, name);
 840                                 ret = -1;
 841                         } else /* make sure caller sets mtime */
 842                                 sxp->st.st_mtime = (time_t)-1;
 843                 }
 844         }
 845
 846         return ret;
 847 }
 848
 849 /* Set extended attributes on indicated filename. */
 850 int set_xattr(const char *fname, const struct file_struct *file,
 851               const char *fnamecmp, stat_x *sxp)
 852 {
 853         int ndx;
 854         item_list *lst = rsync_xal_l.items;
 855
 856         if (dry_run)
 857                 return 1; /* FIXME: --dry-run needs to compute this value */
 858
 859         if (read_only || list_only) {
 860                 errno = EROFS;
 861                 return -1;
 862         }
 863
 864         ndx = F_XATTR(file);
 865         return rsync_xal_set(fname, lst + ndx, fnamecmp, sxp);
 866 }
 867
 868 #ifdef SUPPORT_ACLS
 869 char *get_xattr_acl(const char *fname, int is_access_acl, size_t *len_p)
 870 {
 871         const char *name = is_access_acl ? XACC_ACL_ATTR : XDEF_ACL_ATTR;
 872         *len_p = 0; /* no extra data alloc needed from get_xattr_data() */
 873         return get_xattr_data(fname, name, len_p, 1);
 874 }
 875
 876 int set_xattr_acl(const char *fname, int is_access_acl, const char *buf, size_t buf_len)
 877 {
 878         const char *name = is_access_acl ? XACC_ACL_ATTR : XDEF_ACL_ATTR;
 879         if (sys_lsetxattr(fname, name, buf, buf_len) < 0) {
 880                 rsyserr(FERROR_XFER, errno,
 881                         "set_xattr_acl: lsetxattr(\"%s\",\"%s\") failed",
 882                         fname, name);
 883                 return -1;
 884         }
 885         return 0;
 886 }
 887
 888 int del_def_xattr_acl(const char *fname)
 889 {
 890         return sys_lremovexattr(fname, XDEF_ACL_ATTR);
 891 }
 892 #endif
 893
 894 int get_stat_xattr(const char *fname, int fd, STRUCT_STAT *fst, STRUCT_STAT *xst)
 895 {
 896         int mode, rdev_major, rdev_minor, uid, gid, len;
 897         char buf[256];
 898
 899         if (am_root >= 0 || IS_DEVICE(fst->st_mode) || IS_SPECIAL(fst->st_mode))
 900                 return -1;
 901
 902         if (xst)
 903                 *xst = *fst;
 904         else
 905                 xst = fst;
 906         if (fname) {
 907                 fd = -1;
 908                 len = sys_lgetxattr(fname, XSTAT_ATTR, buf, sizeof buf - 1);
 909         } else {
 910                 fname = "fd";
 911                 len = sys_fgetxattr(fd, XSTAT_ATTR, buf, sizeof buf - 1);
 912         }
 913         if (len >= (int)sizeof buf) {
 914                 len = -1;
 915                 errno = ERANGE;
 916         }
 917         if (len < 0) {
 918                 if (errno == ENOTSUP || errno == ENOATTR)
 919                         return -1;
 920                 if (errno == EPERM && S_ISLNK(fst->st_mode)) {
 921                         xst->st_uid = 0;
 922                         xst->st_gid = 0;
 923                         return 0;
 924                 }
 925                 rsyserr(FERROR_XFER, errno, "failed to read xattr %s for %s",
 926                         XSTAT_ATTR, full_fname(fname));
 927                 return -1;
 928         }
 929         buf[len] = '\0';
 930
 931         if (sscanf(buf, "%o %d,%d %d:%d",
 932                    &mode, &rdev_major, &rdev_minor, &uid, &gid) != 5) {
 933                 rprintf(FERROR, "Corrupt %s xattr attached to %s: \"%s\"\n",
 934                         XSTAT_ATTR, full_fname(fname), buf);
 935                 exit_cleanup(RERR_FILEIO);
 936         }
 937
 938         xst->st_mode = from_wire_mode(mode);
 939         xst->st_rdev = MAKEDEV(rdev_major, rdev_minor);
 940         xst->st_uid = uid;
 941         xst->st_gid = gid;
 942
 943         return 0;
 944 }
 945
 946 int set_stat_xattr(const char *fname, struct file_struct *file, mode_t new_mode)
 947 {
 948         STRUCT_STAT fst, xst;
 949         dev_t rdev;
 950         mode_t mode, fmode;
 951
 952         if (dry_run)
 953                 return 0;
 954
 955         if (read_only || list_only) {
 956                 rsyserr(FERROR_XFER, EROFS, "failed to write xattr %s for %s",
 957                         XSTAT_ATTR, full_fname(fname));
 958                 return -1;
 959         }
 960
 961         if (x_lstat(fname, &fst, &xst) < 0) {
 962                 rsyserr(FERROR_XFER, errno, "failed to re-stat %s",
 963                         full_fname(fname));
 964                 return -1;
 965         }
 966
 967         fst.st_mode &= (_S_IFMT | CHMOD_BITS);
 968         fmode = new_mode & (_S_IFMT | CHMOD_BITS);
 969
 970         if (IS_DEVICE(fmode) || IS_SPECIAL(fmode)) {
 971                 uint32 *devp = F_RDEV_P(file);
 972                 rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
 973         } else
 974                 rdev = 0;
 975
 976         /* Dump the special permissions and enable full owner access. */
 977         mode = (fst.st_mode & _S_IFMT) | (fmode & ACCESSPERMS)
 978              | (S_ISDIR(fst.st_mode) ? 0700 : 0600);
 979         if (fst.st_mode != mode)
 980                 do_chmod(fname, mode);
 981         if (!IS_DEVICE(fst.st_mode) && !IS_SPECIAL(fst.st_mode))
 982                 fst.st_rdev = 0; /* just in case */
 983
 984         if (mode == fmode && fst.st_rdev == rdev
 985          && fst.st_uid == F_OWNER(file) && fst.st_gid == F_GROUP(file)) {
 986                 /* xst.st_mode will be 0 if there's no current stat xattr */
 987                 if (xst.st_mode && sys_lremovexattr(fname, XSTAT_ATTR) < 0) {
 988                         rsyserr(FERROR_XFER, errno,
 989                                 "delete of stat xattr failed for %s",
 990                                 full_fname(fname));
 991                         return -1;
 992                 }
 993                 return 0;
 994         }
 995
 996         if (xst.st_mode != fmode || xst.st_rdev != rdev
 997          || xst.st_uid != F_OWNER(file) || xst.st_gid != F_GROUP(file)) {
 998                 char buf[256];
 999                 int len = snprintf(buf, sizeof buf, "%o %u,%u %u:%u",
1000                         to_wire_mode(fmode),
1001                         (int)major(rdev), (int)minor(rdev),
1002                         F_OWNER(file), F_GROUP(file));
1003                 if (sys_lsetxattr(fname, XSTAT_ATTR, buf, len) < 0) {
1004                         if (errno == EPERM && S_ISLNK(fst.st_mode))
1005                                 return 0;
1006                         rsyserr(FERROR_XFER, errno,
1007                                 "failed to write xattr %s for %s",
1008                                 XSTAT_ATTR, full_fname(fname));
1009                         return -1;
1010                 }
1011         }
1012
1013         return 0;
1014 }
1015
1016 int x_stat(const char *fname, STRUCT_STAT *fst, STRUCT_STAT *xst)
1017 {
1018         int ret = do_stat(fname, fst);
1019         if ((ret < 0 || get_stat_xattr(fname, -1, fst, xst) < 0) && xst)
1020                 xst->st_mode = 0;
1021         return ret;
1022 }
1023
1024 int x_lstat(const char *fname, STRUCT_STAT *fst, STRUCT_STAT *xst)
1025 {
1026         int ret = do_lstat(fname, fst);
1027         if ((ret < 0 || get_stat_xattr(fname, -1, fst, xst) < 0) && xst)
1028                 xst->st_mode = 0;
1029         return ret;
1030 }
1031
1032 int x_fstat(int fd, STRUCT_STAT *fst, STRUCT_STAT *xst)
1033 {
1034         int ret = do_fstat(fd, fst);
1035         if ((ret < 0 || get_stat_xattr(NULL, fd, fst, xst) < 0) && xst)
1036                 xst->st_mode = 0;
1037         return ret;
1038 }
1039
1040 #endif /* SUPPORT_XATTRS */