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, 2007 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   0
  48 #define XSTATE_DONE     1
  49 #define XSTATE_TODO     2
  50 #define XSTATE_LOCAL    3
  51
  52 #define USER_PREFIX "user."
  53 #define UPRE_LEN ((int)sizeof USER_PREFIX - 1)
  54 #define SYSTEM_PREFIX "system."
  55 #define SPRE_LEN ((int)sizeof SYSTEM_PREFIX - 1)
  56
  57 #ifdef HAVE_LINUX_XATTRS
  58 #define MIGHT_NEED_RPRE (am_root < 0)
  59 #define RSYNC_PREFIX USER_PREFIX "rsync."
  60 #else
  61 #define MIGHT_NEED_RPRE am_root
  62 #define RSYNC_PREFIX "rsync."
  63 #endif
  64 #define RPRE_LEN ((int)sizeof RSYNC_PREFIX - 1)
  65
  66 #define XSTAT_ATTR RSYNC_PREFIX "%stat"
  67 #define XACC_ACL_ATTR RSYNC_PREFIX "%aacl"
  68 #define XDEF_ACL_ATTR RSYNC_PREFIX "%dacl"
  69
  70 typedef struct {
  71         char *datum, *name;
  72         size_t datum_len, name_len;
  73 } rsync_xa;
  74
  75 static size_t namebuf_len = 0;
  76 static char *namebuf = NULL;
  77
  78 static item_list empty_xattr = EMPTY_ITEM_LIST;
  79 static item_list rsync_xal_l = EMPTY_ITEM_LIST;
  80
  81 /* ------------------------------------------------------------------------- */
  82
  83 static void rsync_xal_free(item_list *xalp)
  84 {
  85         size_t i;
  86         rsync_xa *rxas = xalp->items;
  87
  88         for (i = 0; i < xalp->count; i++) {
  89                 free(rxas[i].datum);
  90                 /*free(rxas[i].name);*/
  91         }
  92         xalp->count = 0;
  93 }
  94
  95 void free_xattr(stat_x *sxp)
  96 {
  97         if (!sxp->xattr)
  98                 return;
  99         rsync_xal_free(sxp->xattr);
 100         free(sxp->xattr);
 101         sxp->xattr = NULL;
 102 }
 103
 104 static int rsync_xal_compare_names(const void *x1, const void *x2)
 105 {
 106         const rsync_xa *xa1 = x1;
 107         const rsync_xa *xa2 = x2;
 108         return strcmp(xa1->name, xa2->name);
 109 }
 110
 111 static ssize_t get_xattr_names(const char *fname)
 112 {
 113         ssize_t list_len;
 114
 115         if (!namebuf) {
 116                 namebuf_len = 1024;
 117                 namebuf = new_array(char, namebuf_len);
 118                 if (!namebuf)
 119                         out_of_memory("get_xattr_names");
 120         }
 121
 122         /* The length returned includes all the '\0' terminators. */
 123         list_len = sys_llistxattr(fname, namebuf, namebuf_len);
 124         if (list_len > (ssize_t)namebuf_len) {
 125                 list_len = -1;
 126                 errno = ERANGE;
 127         }
 128         if (list_len >= 0)
 129                 return list_len;
 130         if (errno == ENOTSUP)
 131                 return 0;
 132         if (errno == ERANGE) {
 133                 list_len = sys_llistxattr(fname, NULL, 0);
 134                 if (list_len < 0) {
 135                         rsyserr(FERROR_XFER, errno,
 136                                 "get_xattr_names: llistxattr(\"%s\",0) failed",
 137                                 fname);
 138                         return -1;
 139                 }
 140                 if (namebuf_len)
 141                         free(namebuf);
 142                 namebuf_len = list_len + 1024;
 143                 namebuf = new_array(char, namebuf_len);
 144                 if (!namebuf)
 145                         out_of_memory("get_xattr_names");
 146                 list_len = sys_llistxattr(fname, namebuf, namebuf_len);
 147                 if (list_len >= 0)
 148                         return list_len;
 149         }
 150
 151         rsyserr(FERROR_XFER, errno,
 152                 "get_xattr_names: llistxattr(\"%s\",%ld) failed",
 153                 fname, (long)namebuf_len);
 154         return -1;
 155 }
 156
 157 /* On entry, the *len_ptr parameter contains the size of the extra space we
 158  * should allocate when we create a buffer for the data.  On exit, it contains
 159  * the length of the datum. */
 160 static char *get_xattr_data(const char *fname, const char *name, size_t *len_ptr,
 161                             int no_missing_error)
 162 {
 163         size_t datum_len = sys_lgetxattr(fname, name, NULL, 0);
 164         size_t extra_len = *len_ptr;
 165         char *ptr;
 166
 167         *len_ptr = datum_len;
 168
 169         if (datum_len == (size_t)-1) {
 170                 if (errno == ENOTSUP || no_missing_error)
 171                         return NULL;
 172                 rsyserr(FERROR_XFER, errno,
 173                         "get_xattr_data: lgetxattr(\"%s\",\"%s\",0) failed",
 174                         fname, name);
 175                 return NULL;
 176         }
 177
 178         if (!datum_len && !extra_len)
 179                 extra_len = 1; /* request non-zero amount of memory */
 180         if (datum_len + extra_len < datum_len /* checks for overflow */
 181          || !(ptr = new_array(char, datum_len + extra_len)))
 182                 out_of_memory("get_xattr_data");
 183
 184         if (datum_len) {
 185                 size_t len = sys_lgetxattr(fname, name, ptr, datum_len);
 186                 if (len != datum_len) {
 187                         if (len == (size_t)-1) {
 188                                 rsyserr(FERROR_XFER, errno,
 189                                     "get_xattr_data: lgetxattr(\"%s\",\"%s\",%ld)"
 190                                     " failed", fname, name, (long)datum_len);
 191                         } else {
 192                                 rprintf(FERROR_XFER,
 193                                     "get_xattr_data: lgetxattr(\"%s\",\"%s\",%ld)"
 194                                     " returned %ld\n", fname, name,
 195                                     (long)datum_len, (long)len);
 196                         }
 197                         free(ptr);
 198                         return NULL;
 199                 }
 200         }
 201
 202         return ptr;
 203 }
 204
 205 static int rsync_xal_get(const char *fname, item_list *xalp)
 206 {
 207         ssize_t list_len, name_len;
 208         size_t datum_len, name_offset;
 209         char *name, *ptr;
 210 #ifdef HAVE_LINUX_XATTRS
 211         int user_only = am_sender ? 0 : !am_root;
 212 #endif
 213
 214         /* This puts the name list into the "namebuf" buffer. */
 215         if ((list_len = get_xattr_names(fname)) < 0)
 216                 return -1;
 217
 218         for (name = namebuf; list_len > 0; name += name_len) {
 219                 rsync_xa *rxa;
 220
 221                 name_len = strlen(name) + 1;
 222                 list_len -= name_len;
 223
 224 #ifdef HAVE_LINUX_XATTRS
 225                 /* We always ignore the system namespace, and non-root
 226                  * ignores everything but the user namespace. */
 227                 if (user_only ? !HAS_PREFIX(name, USER_PREFIX)
 228                               : HAS_PREFIX(name, SYSTEM_PREFIX))
 229                         continue;
 230 #endif
 231
 232                 /* No rsync.%FOO attributes are copied w/o 2 -X options. */
 233                 if (name_len > RPRE_LEN && name[RPRE_LEN] == '%'
 234                  && HAS_PREFIX(name, RSYNC_PREFIX)) {
 235                         if ((am_sender && preserve_xattrs < 2)
 236                          || (am_root < 0 && strcmp(name, XSTAT_ATTR) == 0))
 237                                 continue;
 238                 }
 239
 240                 datum_len = name_len; /* Pass extra size to get_xattr_data() */
 241                 if (!(ptr = get_xattr_data(fname, name, &datum_len, 0)))
 242                         return -1;
 243
 244                 if (datum_len > MAX_FULL_DATUM) {
 245                         /* For large datums, we store a flag and a checksum. */
 246                         name_offset = 1 + MAX_DIGEST_LEN;
 247                         sum_init(checksum_seed);
 248                         sum_update(ptr, datum_len);
 249                         free(ptr);
 250
 251                         if (!(ptr = new_array(char, name_offset + name_len)))
 252                                 out_of_memory("rsync_xal_get");
 253                         *ptr = XSTATE_ABBREV;
 254                         sum_end(ptr + 1);
 255                 } else
 256                         name_offset = datum_len;
 257
 258 #ifdef HAVE_LINUX_XATTRS
 259                 if (am_root < 0 && name_len > RPRE_LEN && name[RPRE_LEN] != '%'
 260                  && HAS_PREFIX(name, RSYNC_PREFIX)) {
 261                         name += RPRE_LEN;
 262                         name_len -= RPRE_LEN;
 263                 }
 264 #endif
 265
 266                 rxa = EXPAND_ITEM_LIST(xalp, rsync_xa, RSYNC_XAL_INITIAL);
 267                 rxa->name = ptr + name_offset;
 268                 memcpy(rxa->name, name, name_len);
 269                 rxa->datum = ptr;
 270                 rxa->name_len = name_len;
 271                 rxa->datum_len = datum_len;
 272         }
 273         if (xalp->count > 1)
 274                 qsort(xalp->items, xalp->count, sizeof (rsync_xa), rsync_xal_compare_names);
 275         return 0;
 276 }
 277
 278 /* Read the xattr(s) for this filename. */
 279 int get_xattr(const char *fname, stat_x *sxp)
 280 {
 281         sxp->xattr = new(item_list);
 282         *sxp->xattr = empty_xattr;
 283         if (rsync_xal_get(fname, sxp->xattr) < 0) {
 284                 free_xattr(sxp);
 285                 return -1;
 286         }
 287         return 0;
 288 }
 289
 290 static int find_matching_xattr(item_list *xalp)
 291 {
 292         size_t i, j;
 293         item_list *lst = rsync_xal_l.items;
 294
 295         for (i = 0; i < rsync_xal_l.count; i++) {
 296                 rsync_xa *rxas1 = lst[i].items;
 297                 rsync_xa *rxas2 = xalp->items;
 298
 299                 /* Wrong number of elements? */
 300                 if (lst[i].count != xalp->count)
 301                         continue;
 302                 /* any elements different? */
 303                 for (j = 0; j < xalp->count; j++) {
 304                         if (rxas1[j].name_len != rxas2[j].name_len
 305                          || rxas1[j].datum_len != rxas2[j].datum_len
 306                          || strcmp(rxas1[j].name, rxas2[j].name))
 307                                 break;
 308                         if (rxas1[j].datum_len > MAX_FULL_DATUM) {
 309                                 if (memcmp(rxas1[j].datum + 1,
 310                                            rxas2[j].datum + 1,
 311                                            MAX_DIGEST_LEN) != 0)
 312                                         break;
 313                         } else {
 314                                 if (memcmp(rxas1[j].datum, rxas2[j].datum,
 315                                            rxas2[j].datum_len))
 316                                         break;
 317                         }
 318                 }
 319                 /* no differences found.  This is The One! */
 320                 if (j == xalp->count)
 321                         return i;
 322         }
 323
 324         return -1;
 325 }
 326
 327 /* Store *xalp on the end of rsync_xal_l */
 328 static void rsync_xal_store(item_list *xalp)
 329 {
 330         item_list *new_lst = EXPAND_ITEM_LIST(&rsync_xal_l, item_list, RSYNC_XAL_LIST_INITIAL);
 331         /* Since the following call starts a new list, we know it will hold the
 332          * entire initial-count, not just enough space for one new item. */
 333         *new_lst = empty_xattr;
 334         (void)EXPAND_ITEM_LIST(new_lst, rsync_xa, xalp->count);
 335         memcpy(new_lst->items, xalp->items, xalp->count * sizeof (rsync_xa));
 336         new_lst->count = xalp->count;
 337         xalp->count = 0;
 338 }
 339
 340 /* Send the make_xattr()-generated xattr list for this flist entry. */
 341 int send_xattr(stat_x *sxp, int f)
 342 {
 343         int ndx = find_matching_xattr(sxp->xattr);
 344
 345         /* Send 0 (-1 + 1) to indicate that literal xattr data follows. */
 346         write_varint(f, ndx + 1);
 347
 348         if (ndx < 0) {
 349                 rsync_xa *rxa;
 350                 int count = sxp->xattr->count;
 351                 write_varint(f, count);
 352                 for (rxa = sxp->xattr->items; count--; rxa++) {
 353 #ifdef HAVE_LINUX_XATTRS
 354                         write_varint(f, rxa->name_len);
 355                         write_varint(f, rxa->datum_len);
 356                         write_buf(f, rxa->name, rxa->name_len);
 357 #else
 358                         /* We strip the rsync prefix from disguised namespaces
 359                          * and put everything else in the user namespace. */
 360                         if (HAS_PREFIX(rxa->name, RSYNC_PREFIX)
 361                          && rxa->name[RPRE_LEN] != '%') {
 362                                 write_varint(f, rxa->name_len - RPRE_LEN);
 363                                 write_varint(f, rxa->datum_len);
 364                                 write_buf(f, rxa->name + RPRE_LEN, rxa->name_len - RPRE_LEN);
 365                         } else {
 366                                 write_varint(f, rxa->name_len + UPRE_LEN);
 367                                 write_varint(f, rxa->datum_len);
 368                                 write_buf(f, USER_PREFIX, UPRE_LEN);
 369                                 write_buf(f, rxa->name, rxa->name_len);
 370                         }
 371 #endif
 372                         if (rxa->datum_len > MAX_FULL_DATUM)
 373                                 write_buf(f, rxa->datum + 1, MAX_DIGEST_LEN);
 374                         else
 375                                 write_buf(f, rxa->datum, rxa->datum_len);
 376                 }
 377                 ndx = rsync_xal_l.count; /* pre-incremented count */
 378                 rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
 379         }
 380
 381         return ndx;
 382 }
 383
 384 /* Return a flag indicating if we need to change a file's xattrs.  If
 385  * "find_all" is specified, also mark any abbreviated xattrs that we
 386  * need so that send_xattr_request() can tell the sender about them. */
 387 int xattr_diff(struct file_struct *file, stat_x *sxp, int find_all)
 388 {
 389         item_list *lst = rsync_xal_l.items;
 390         rsync_xa *snd_rxa, *rec_rxa;
 391         int snd_cnt, rec_cnt;
 392         int cmp, same, xattrs_equal = 1;
 393
 394         if (sxp && XATTR_READY(*sxp)) {
 395                 rec_rxa = sxp->xattr->items;
 396                 rec_cnt = sxp->xattr->count;
 397         } else {
 398                 rec_rxa = NULL;
 399                 rec_cnt = 0;
 400         }
 401
 402         if (F_XATTR(file) >= 0)
 403                 lst += F_XATTR(file);
 404         else
 405                 lst = &empty_xattr;
 406
 407         snd_rxa = lst->items;
 408         snd_cnt = lst->count;
 409
 410         /* If the count of the sender's xattrs is different from our
 411          * (receiver's) xattrs, the lists are not the same. */
 412         if (snd_cnt != rec_cnt) {
 413                 if (!find_all)
 414                         return 1;
 415                 xattrs_equal = 0;
 416         }
 417
 418         while (snd_cnt) {
 419                 cmp = rec_cnt ? strcmp(snd_rxa->name, rec_rxa->name) : -1;
 420                 if (cmp > 0)
 421                         same = 0;
 422                 else if (snd_rxa->datum_len > MAX_FULL_DATUM) {
 423                         same = cmp == 0 && snd_rxa->datum_len == rec_rxa->datum_len
 424                             && memcmp(snd_rxa->datum + 1, rec_rxa->datum + 1,
 425                                       MAX_DIGEST_LEN) == 0;
 426                         /* Flag unrequested items that we need. */
 427                         if (!same && find_all && snd_rxa->datum[0] == XSTATE_ABBREV)
 428                                 snd_rxa->datum[0] = XSTATE_TODO;
 429                 } else {
 430                         same = cmp == 0 && snd_rxa->datum_len == rec_rxa->datum_len
 431                             && memcmp(snd_rxa->datum, rec_rxa->datum,
 432                                       snd_rxa->datum_len) == 0;
 433                 }
 434                 if (!same) {
 435                         if (!find_all)
 436                                 return 1;
 437                         xattrs_equal = 0;
 438                 }
 439
 440                 if (cmp <= 0) {
 441                         snd_rxa++;
 442                         snd_cnt--;
 443                 }
 444                 if (cmp >= 0) {
 445                         rec_rxa++;
 446                         rec_cnt--;
 447                 }
 448         }
 449
 450         if (rec_cnt)
 451                 xattrs_equal = 0;
 452
 453         return !xattrs_equal;
 454 }
 455
 456 /* When called by the generator with a NULL fname, this tells the sender
 457  * which abbreviated xattr values we need.  When called by the sender
 458  * (with a non-NULL fname), we send all the extra xattr data it needs. */
 459 void send_xattr_request(const char *fname, struct file_struct *file, int f_out)
 460 {
 461         item_list *lst = rsync_xal_l.items;
 462         int j, cnt, prior_req = -1;
 463         rsync_xa *rxa;
 464
 465         lst += F_XATTR(file);
 466         cnt = lst->count;
 467         for (rxa = lst->items, j = 0; j < cnt; rxa++, j++) {
 468                 if (rxa->datum_len <= MAX_FULL_DATUM)
 469                         continue;
 470                 switch (rxa->datum[0]) {
 471                 case XSTATE_LOCAL:
 472                         /* Items set locally will get cached by receiver. */
 473                         rxa->datum[0] = XSTATE_DONE;
 474                         continue;
 475                 case XSTATE_TODO:
 476                         break;
 477                 default:
 478                         continue;
 479                 }
 480
 481                 /* Flag that we handled this abbreviated item. */
 482                 rxa->datum[0] = XSTATE_DONE;
 483
 484                 write_varint(f_out, j - prior_req);
 485                 prior_req = j;
 486
 487                 if (fname) {
 488                         size_t len = 0;
 489                         char *ptr;
 490
 491                         /* Re-read the long datum. */
 492                         if (!(ptr = get_xattr_data(fname, rxa->name, &len, 0))) {
 493                                 rprintf(FERROR_XFER, "failed to re-read xattr %s for %s\n", rxa->name, fname);
 494                                 write_varint(f_out, 0);
 495                                 continue;
 496                         }
 497
 498                         write_varint(f_out, len); /* length might have changed! */
 499                         write_buf(f_out, ptr, len);
 500                         free(ptr);
 501                 }
 502         }
 503
 504         write_byte(f_out, 0); /* end the list */
 505 }
 506
 507 /* Any items set locally by the generator that the receiver doesn't
 508  * get told about get changed back to XSTATE_ABBREV. */
 509 void xattr_clear_locals(struct file_struct *file)
 510 {
 511         item_list *lst = rsync_xal_l.items;
 512         rsync_xa *rxa;
 513         int cnt;
 514
 515         if (F_XATTR(file) < 0)
 516                 return;
 517
 518         lst += F_XATTR(file);
 519         cnt = lst->count;
 520         for (rxa = lst->items; cnt--; rxa++) {
 521                 if (rxa->datum_len <= MAX_FULL_DATUM)
 522                         continue;
 523                 if (rxa->datum[0] == XSTATE_LOCAL)
 524                         rxa->datum[0] = XSTATE_ABBREV;
 525         }
 526 }
 527
 528 /* When called by the sender, read the request from the generator and mark
 529  * any needed xattrs with a flag that lets us know they need to be sent to
 530  * the receiver.  When called by the receiver, reads the sent data and
 531  * stores it in place of its checksum. */
 532 int recv_xattr_request(struct file_struct *file, int f_in)
 533 {
 534         item_list *lst = rsync_xal_l.items;
 535         char *old_datum, *name;
 536         rsync_xa *rxa;
 537         int rel_pos, cnt, got_xattr_data = 0;
 538
 539         if (F_XATTR(file) < 0) {
 540                 rprintf(FERROR, "recv_xattr_request: internal data error!\n");
 541                 exit_cleanup(RERR_STREAMIO);
 542         }
 543         lst += F_XATTR(file);
 544
 545         cnt = lst->count;
 546         rxa = lst->items;
 547         rxa -= 1;
 548         while ((rel_pos = read_varint(f_in)) != 0) {
 549                 rxa += rel_pos;
 550                 cnt -= rel_pos;
 551                 if (cnt < 0 || rxa->datum_len <= MAX_FULL_DATUM
 552                  || rxa->datum[0] != XSTATE_ABBREV) {
 553                         rprintf(FERROR, "recv_xattr_request: internal abbrev error!\n");
 554                         exit_cleanup(RERR_STREAMIO);
 555                 }
 556
 557                 if (am_sender) {
 558                         rxa->datum[0] = XSTATE_TODO;
 559                         continue;
 560                 }
 561
 562                 old_datum = rxa->datum;
 563                 rxa->datum_len = read_varint(f_in);
 564
 565                 if (rxa->name_len + rxa->datum_len < rxa->name_len)
 566                         out_of_memory("recv_xattr_request"); /* overflow */
 567                 rxa->datum = new_array(char, rxa->datum_len + rxa->name_len);
 568                 if (!rxa->datum)
 569                         out_of_memory("recv_xattr_request");
 570                 name = rxa->datum + rxa->datum_len;
 571                 memcpy(name, rxa->name, rxa->name_len);
 572                 rxa->name = name;
 573                 free(old_datum);
 574                 read_buf(f_in, rxa->datum, rxa->datum_len);
 575                 got_xattr_data = 1;
 576         }
 577
 578         return got_xattr_data;
 579 }
 580
 581 /* ------------------------------------------------------------------------- */
 582
 583 /* receive and build the rsync_xattr_lists */
 584 void receive_xattr(struct file_struct *file, int f)
 585 {
 586         static item_list temp_xattr = EMPTY_ITEM_LIST;
 587         int count;
 588         int ndx = read_varint(f);
 589
 590         if (ndx < 0 || (size_t)ndx > rsync_xal_l.count) {
 591                 rprintf(FERROR, "receive_xattr: xa index %d out of"
 592                         " range for %s\n", ndx, f_name(file, NULL));
 593                 exit_cleanup(RERR_STREAMIO);
 594         }
 595
 596         if (ndx != 0) {
 597                 F_XATTR(file) = ndx - 1;
 598                 return;
 599         }
 600
 601         if ((count = read_varint(f)) != 0) {
 602                 (void)EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, count);
 603                 temp_xattr.count = 0;
 604         }
 605
 606         while (count--) {
 607                 char *ptr, *name;
 608                 rsync_xa *rxa;
 609                 size_t name_len = read_varint(f);
 610                 size_t datum_len = read_varint(f);
 611                 size_t dget_len = datum_len > MAX_FULL_DATUM ? 1 + MAX_DIGEST_LEN : datum_len;
 612                 size_t extra_len = MIGHT_NEED_RPRE ? RPRE_LEN : 0;
 613                 if (dget_len + extra_len < dget_len)
 614                         out_of_memory("receive_xattr"); /* overflow */
 615                 if (dget_len + extra_len + name_len < dget_len)
 616                         out_of_memory("receive_xattr"); /* overflow */
 617                 ptr = new_array(char, dget_len + extra_len + name_len);
 618                 if (!ptr)
 619                         out_of_memory("receive_xattr");
 620                 name = ptr + dget_len + extra_len;
 621                 read_buf(f, name, name_len);
 622                 if (dget_len == datum_len)
 623                         read_buf(f, ptr, dget_len);
 624                 else {
 625                         *ptr = XSTATE_ABBREV;
 626                         read_buf(f, ptr + 1, MAX_DIGEST_LEN);
 627                 }
 628 #ifdef HAVE_LINUX_XATTRS
 629                 /* Non-root can only save the user namespace. */
 630                         if (am_root <= 0 && !HAS_PREFIX(name, USER_PREFIX)) {
 631                                 if (!am_root) {
 632                                         free(ptr);
 633                                         continue;
 634                                 }
 635                                 name -= RPRE_LEN;
 636                                 name_len += RPRE_LEN;
 637                                 memcpy(name, RSYNC_PREFIX, RPRE_LEN);
 638                 }
 639 #else
 640                 /* This OS only has a user namespace, so we either
 641                  * strip the user prefix, or we put a non-user
 642                  * namespace inside our rsync hierarchy. */
 643                 if (HAS_PREFIX(name, USER_PREFIX)) {
 644                         name += UPRE_LEN;
 645                         name_len -= UPRE_LEN;
 646                 } else if (am_root) {
 647                         name -= RPRE_LEN;
 648                         name_len += RPRE_LEN;
 649                         memcpy(name, RSYNC_PREFIX, RPRE_LEN);
 650                 } else {
 651                         free(ptr);
 652                         continue;
 653                 }
 654 #endif
 655                 /* No rsync.%FOO attributes are copied w/o 2 -X options. */
 656                 if (preserve_xattrs < 2 && name_len > RPRE_LEN
 657                  && name[RPRE_LEN] == '%' && HAS_PREFIX(name, RSYNC_PREFIX)) {
 658                         free(ptr);
 659                         continue;
 660                 }
 661                 rxa = EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, 1);
 662                 rxa->name = name;
 663                 rxa->datum = ptr;
 664                 rxa->name_len = name_len;
 665                 rxa->datum_len = datum_len;
 666         }
 667
 668         ndx = rsync_xal_l.count; /* pre-incremented count */
 669         rsync_xal_store(&temp_xattr); /* adds item to rsync_xal_l */
 670
 671         F_XATTR(file) = ndx;
 672 }
 673
 674 /* Turn the xattr data in stat_x into cached xattr data, setting the index
 675  * values in the file struct. */
 676 void cache_xattr(struct file_struct *file, stat_x *sxp)
 677 {
 678         int ndx;
 679
 680         if (!sxp->xattr)
 681                 return;
 682
 683         ndx = find_matching_xattr(sxp->xattr);
 684         if (ndx < 0)
 685                 rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
 686
 687         F_XATTR(file) = ndx;
 688 }
 689
 690 static int rsync_xal_set(const char *fname, item_list *xalp,
 691                          const char *fnamecmp, stat_x *sxp)
 692 {
 693         rsync_xa *rxas = xalp->items;
 694         ssize_t list_len;
 695         size_t i, len;
 696         char *name, *ptr, sum[MAX_DIGEST_LEN];
 697         int name_len, ret = 0;
 698
 699         /* This puts the current name list into the "namebuf" buffer. */
 700         if ((list_len = get_xattr_names(fname)) < 0)
 701                 return -1;
 702
 703         for (i = 0; i < xalp->count; i++) {
 704                 name = rxas[i].name;
 705
 706                 if (XATTR_ABBREV(rxas[i])) {
 707                         /* See if the fnamecmp version is identical. */
 708                         len = name_len = rxas[i].name_len;
 709                         if ((ptr = get_xattr_data(fnamecmp, name, &len, 1)) == NULL) {
 710                           still_abbrev:
 711                                 if (am_generator)
 712                                         continue;
 713                                 rprintf(FERROR, "Missing abbreviated xattr value, %s, for %s\n",
 714                                         rxas[i].name, full_fname(fname));
 715                                 ret = -1;
 716                                 continue;
 717                         }
 718                         if (len != rxas[i].datum_len) {
 719                                 free(ptr);
 720                                 goto still_abbrev;
 721                         }
 722
 723                         sum_init(checksum_seed);
 724                         sum_update(ptr, len);
 725                         sum_end(sum);
 726                         if (memcmp(sum, rxas[i].datum + 1, MAX_DIGEST_LEN) != 0) {
 727                                 free(ptr);
 728                                 goto still_abbrev;
 729                         }
 730
 731                         if (fname == fnamecmp)
 732                                 ; /* Value is already set when identical */
 733                         else if (sys_lsetxattr(fname, name, ptr, len) < 0) {
 734                                 rsyserr(FERROR_XFER, errno,
 735                                         "rsync_xal_set: lsetxattr(\"%s\",\"%s\") failed",
 736                                         fname, name);
 737                                 ret = -1;
 738                         } else /* make sure caller sets mtime */
 739                                 sxp->st.st_mtime = (time_t)-1;
 740
 741                         if (am_generator) { /* generator items stay abbreviated */
 742                                 if (rxas[i].datum[0] == XSTATE_ABBREV)
 743                                         rxas[i].datum[0] = XSTATE_LOCAL;
 744                                 free(ptr);
 745                                 continue;
 746                         }
 747
 748                         memcpy(ptr + len, name, name_len);
 749                         free(rxas[i].datum);
 750
 751                         rxas[i].name = name = ptr + len;
 752                         rxas[i].datum = ptr;
 753                         continue;
 754                 }
 755
 756                 if (sys_lsetxattr(fname, name, rxas[i].datum, rxas[i].datum_len) < 0) {
 757                         rsyserr(FERROR_XFER, errno,
 758                                 "rsync_xal_set: lsetxattr(\"%s\",\"%s\") failed",
 759                                 fname, name);
 760                         ret = -1;
 761                 } else /* make sure caller sets mtime */
 762                         sxp->st.st_mtime = (time_t)-1;
 763         }
 764
 765         /* Remove any extraneous names. */
 766         for (name = namebuf; list_len > 0; name += name_len) {
 767                 name_len = strlen(name) + 1;
 768                 list_len -= name_len;
 769
 770 #ifdef HAVE_LINUX_XATTRS
 771                 /* We always ignore the system namespace, and non-root
 772                  * ignores everything but the user namespace. */
 773                 if (am_root ? HAS_PREFIX(name, SYSTEM_PREFIX)
 774                             : !HAS_PREFIX(name, USER_PREFIX))
 775                         continue;
 776 #endif
 777                 if (am_root < 0 && name_len > RPRE_LEN
 778                  && name[RPRE_LEN] == '%' && strcmp(name, XSTAT_ATTR) == 0)
 779                         continue;
 780
 781                 for (i = 0; i < xalp->count; i++) {
 782                         if (strcmp(name, rxas[i].name) == 0)
 783                                 break;
 784                 }
 785                 if (i == xalp->count) {
 786                         if (sys_lremovexattr(fname, name) < 0) {
 787                                 rsyserr(FERROR_XFER, errno,
 788                                         "rsync_xal_clear: lremovexattr(\"%s\",\"%s\") failed",
 789                                         fname, name);
 790                                 ret = -1;
 791                         } else /* make sure caller sets mtime */
 792                                 sxp->st.st_mtime = (time_t)-1;
 793                 }
 794         }
 795
 796         return ret;
 797 }
 798
 799 /* Set extended attributes on indicated filename. */
 800 int set_xattr(const char *fname, const struct file_struct *file,
 801               const char *fnamecmp, stat_x *sxp)
 802 {
 803         int ndx;
 804         item_list *lst = rsync_xal_l.items;
 805
 806         if (dry_run)
 807                 return 1; /* FIXME: --dry-run needs to compute this value */
 808
 809         if (read_only || list_only) {
 810                 errno = EROFS;
 811                 return -1;
 812         }
 813
 814         ndx = F_XATTR(file);
 815         return rsync_xal_set(fname, lst + ndx, fnamecmp, sxp);
 816 }
 817
 818 #ifdef SUPPORT_ACLS
 819 char *get_xattr_acl(const char *fname, int is_access_acl, size_t *len_p)
 820 {
 821         const char *name = is_access_acl ? XACC_ACL_ATTR : XDEF_ACL_ATTR;
 822         *len_p = 0; /* no extra data alloc needed from get_xattr_data() */
 823         return get_xattr_data(fname, name, len_p, 1);
 824 }
 825
 826 int set_xattr_acl(const char *fname, int is_access_acl, const char *buf, size_t buf_len)
 827 {
 828         const char *name = is_access_acl ? XACC_ACL_ATTR : XDEF_ACL_ATTR;
 829         if (sys_lsetxattr(fname, name, buf, buf_len) < 0) {
 830                 rsyserr(FERROR_XFER, errno,
 831                         "set_xattr_acl: lsetxattr(\"%s\",\"%s\") failed",
 832                         fname, name);
 833                 return -1;
 834         }
 835         return 0;
 836 }
 837
 838 int del_def_xattr_acl(const char *fname)
 839 {
 840         return sys_lremovexattr(fname, XDEF_ACL_ATTR);
 841 }
 842 #endif
 843
 844 int get_stat_xattr(const char *fname, int fd, STRUCT_STAT *fst, STRUCT_STAT *xst)
 845 {
 846         int mode, rdev_major, rdev_minor, uid, gid, len;
 847         char buf[256];
 848
 849         if (am_root >= 0 || IS_DEVICE(fst->st_mode) || IS_SPECIAL(fst->st_mode))
 850                 return -1;
 851
 852         if (xst)
 853                 *xst = *fst;
 854         else
 855                 xst = fst;
 856         if (fname) {
 857                 fd = -1;
 858                 len = sys_lgetxattr(fname, XSTAT_ATTR, buf, sizeof buf - 1);
 859         } else {
 860                 fname = "fd";
 861                 len = sys_fgetxattr(fd, XSTAT_ATTR, buf, sizeof buf - 1);
 862         }
 863         if (len >= (int)sizeof buf) {
 864                 len = -1;
 865                 errno = ERANGE;
 866         }
 867         if (len < 0) {
 868                 if (errno == ENOTSUP || errno == ENOATTR)
 869                         return -1;
 870                 if (errno == EPERM && S_ISLNK(fst->st_mode)) {
 871                         xst->st_uid = 0;
 872                         xst->st_gid = 0;
 873                         return 0;
 874                 }
 875                 rsyserr(FERROR_XFER, errno, "failed to read xattr %s for %s",
 876                         XSTAT_ATTR, full_fname(fname));
 877                 return -1;
 878         }
 879         buf[len] = '\0';
 880
 881         if (sscanf(buf, "%o %d,%d %d:%d",
 882                    &mode, &rdev_major, &rdev_minor, &uid, &gid) != 5) {
 883                 rprintf(FERROR, "Corrupt %s xattr attached to %s: \"%s\"\n",
 884                         XSTAT_ATTR, full_fname(fname), buf);
 885                 exit_cleanup(RERR_FILEIO);
 886         }
 887
 888         xst->st_mode = from_wire_mode(mode);
 889         xst->st_rdev = MAKEDEV(rdev_major, rdev_minor);
 890         xst->st_uid = uid;
 891         xst->st_gid = gid;
 892
 893         return 0;
 894 }
 895
 896 int set_stat_xattr(const char *fname, struct file_struct *file, mode_t new_mode)
 897 {
 898         STRUCT_STAT fst, xst;
 899         dev_t rdev;
 900         mode_t mode, fmode;
 901
 902         if (dry_run)
 903                 return 0;
 904
 905         if (read_only || list_only) {
 906                 rsyserr(FERROR_XFER, EROFS, "failed to write xattr %s for %s",
 907                         XSTAT_ATTR, full_fname(fname));
 908                 return -1;
 909         }
 910
 911         if (x_lstat(fname, &fst, &xst) < 0) {
 912                 rsyserr(FERROR_XFER, errno, "failed to re-stat %s",
 913                         full_fname(fname));
 914                 return -1;
 915         }
 916
 917         fst.st_mode &= (_S_IFMT | CHMOD_BITS);
 918         fmode = new_mode & (_S_IFMT | CHMOD_BITS);
 919
 920         if (IS_DEVICE(fmode) || IS_SPECIAL(fmode)) {
 921                 uint32 *devp = F_RDEV_P(file);
 922                 rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
 923         } else
 924                 rdev = 0;
 925
 926         /* Dump the special permissions and enable full owner access. */
 927         mode = (fst.st_mode & _S_IFMT) | (fmode & ACCESSPERMS)
 928              | (S_ISDIR(fst.st_mode) ? 0700 : 0600);
 929         if (fst.st_mode != mode)
 930                 do_chmod(fname, mode);
 931         if (!IS_DEVICE(fst.st_mode) && !IS_SPECIAL(fst.st_mode))
 932                 fst.st_rdev = 0; /* just in case */
 933
 934         if (mode == fmode && fst.st_rdev == rdev
 935          && fst.st_uid == F_OWNER(file) && fst.st_gid == F_GROUP(file)) {
 936                 /* xst.st_mode will be 0 if there's no current stat xattr */
 937                 if (xst.st_mode && sys_lremovexattr(fname, XSTAT_ATTR) < 0) {
 938                         rsyserr(FERROR_XFER, errno,
 939                                 "delete of stat xattr failed for %s",
 940                                 full_fname(fname));
 941                         return -1;
 942                 }
 943                 return 0;
 944         }
 945
 946         if (xst.st_mode != fmode || xst.st_rdev != rdev
 947          || xst.st_uid != F_OWNER(file) || xst.st_gid != F_GROUP(file)) {
 948                 char buf[256];
 949                 int len = snprintf(buf, sizeof buf, "%o %u,%u %u:%u",
 950                         to_wire_mode(fmode),
 951                         (int)major(rdev), (int)minor(rdev),
 952                         F_OWNER(file), F_GROUP(file));
 953                 if (sys_lsetxattr(fname, XSTAT_ATTR, buf, len) < 0) {
 954                         if (errno == EPERM && S_ISLNK(fst.st_mode))
 955                                 return 0;
 956                         rsyserr(FERROR_XFER, errno,
 957                                 "failed to write xattr %s for %s",
 958                                 XSTAT_ATTR, full_fname(fname));
 959                         return -1;
 960                 }
 961         }
 962
 963         return 0;
 964 }
 965
 966 int x_stat(const char *fname, STRUCT_STAT *fst, STRUCT_STAT *xst)
 967 {
 968         int ret = do_stat(fname, fst);
 969         if ((ret < 0 || get_stat_xattr(fname, -1, fst, xst) < 0) && xst)
 970                 xst->st_mode = 0;
 971         return ret;
 972 }
 973
 974 int x_lstat(const char *fname, STRUCT_STAT *fst, STRUCT_STAT *xst)
 975 {
 976         int ret = do_lstat(fname, fst);
 977         if ((ret < 0 || get_stat_xattr(fname, -1, fst, xst) < 0) && xst)
 978                 xst->st_mode = 0;
 979         return ret;
 980 }
 981
 982 int x_fstat(int fd, STRUCT_STAT *fst, STRUCT_STAT *xst)
 983 {
 984         int ret = do_fstat(fd, fst);
 985         if ((ret < 0 || get_stat_xattr(NULL, fd, fst, xst) < 0) && xst)
 986                 xst->st_mode = 0;
 987         return ret;
 988 }
 989
 990 #endif /* SUPPORT_XATTRS */