root/source4/ntvfs/posix/pvfs_streams.c

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DEFINITIONS

This source file includes following definitions.
  1. stream_name_normalise
  2. stream_name_cmp
  3. pvfs_stream_information
  4. pvfs_stream_info
  5. pvfs_stream_update_size
  6. pvfs_stream_rename
  7. pvfs_stream_create
  8. pvfs_stream_delete
  9. pvfs_stream_load
  10. pvfs_stream_read
  11. pvfs_stream_write
  12. pvfs_stream_truncate

   1 /* 
   2    Unix SMB/CIFS implementation.
   3 
   4    POSIX NTVFS backend - alternate data streams
   5 
   6    Copyright (C) Andrew Tridgell 2004
   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
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21 
  22 #include "includes.h"
  23 #include "vfs_posix.h"
  24 #include "librpc/gen_ndr/xattr.h"
  25 
  26 /*
  27   normalise a stream name, removing a :$DATA suffix if there is one 
  28   Note: this returns the existing pointer to the name if the name does 
  29         not need normalising
  30  */
  31 static const char *stream_name_normalise(TALLOC_CTX *ctx, const char *name)
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  32 {
  33         const char *c = strchr_m(name, ':');
  34         if (c == NULL || strcasecmp_m(c, ":$DATA") != 0) {
  35                 return name;
  36         }
  37         return talloc_strndup(ctx, name, c-name);
  38 }
  39 
  40 /*
  41   compare two stream names, taking account of the default $DATA extension
  42  */
  43 static int stream_name_cmp(const char *name1, const char *name2)
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  44 {
  45         const char *c1, *c2;
  46         int l1, l2, ret;
  47         c1 = strchr_m(name1, ':');
  48         c2 = strchr_m(name2, ':');
  49         
  50         /* check the first part is the same */
  51         l1 = c1?(c1 - name1):strlen(name1);
  52         l2 = c2?(c2 - name2):strlen(name2);
  53         if (l1 != l2) {
  54                 return l1 - l2;
  55         }
  56         ret = strncasecmp_m(name1, name2, l1);
  57         if (ret != 0) {
  58                 return ret;
  59         }
  60 
  61         /* the first parts are the same, check the suffix */
  62         if (c1 && c2) {
  63                 return strcasecmp_m(c1, c2);
  64         }
  65 
  66         if (c1) {
  67                 return strcasecmp_m(c1, ":$DATA");
  68         }
  69         if (c2) {
  70                 return strcasecmp_m(c2, ":$DATA");
  71         }
  72 
  73         /* neither names have a suffix */
  74         return 0;
  75 }
  76 
  77 
  78 /*
  79   return the list of file streams for RAW_FILEINFO_STREAM_INFORMATION
  80 */
  81 NTSTATUS pvfs_stream_information(struct pvfs_state *pvfs, 
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  82                                  TALLOC_CTX *mem_ctx,
  83                                  struct pvfs_filename *name, int fd, 
  84                                  struct stream_information *info)
  85 {
  86         struct xattr_DosStreams *streams;
  87         int i;
  88         NTSTATUS status;
  89 
  90         /* directories don't have streams */
  91         if (name->dos.attrib & FILE_ATTRIBUTE_DIRECTORY) {
  92                 info->num_streams = 0;
  93                 info->streams = NULL;
  94                 return NT_STATUS_OK;
  95         }
  96 
  97         streams = talloc(mem_ctx, struct xattr_DosStreams);
  98         if (streams == NULL) {
  99                 return NT_STATUS_NO_MEMORY;
 100         }
 101 
 102         status = pvfs_streams_load(pvfs, name, fd, streams);
 103         if (!NT_STATUS_IS_OK(status)) {
 104                 ZERO_STRUCTP(streams);
 105         }
 106 
 107         info->num_streams = streams->num_streams+1;
 108         info->streams = talloc_array(mem_ctx, struct stream_struct, info->num_streams);
 109         if (!info->streams) {
 110                 return NT_STATUS_NO_MEMORY;
 111         }
 112 
 113         info->streams[0].size          = name->st.st_size;
 114         info->streams[0].alloc_size    = name->dos.alloc_size;
 115         info->streams[0].stream_name.s = talloc_strdup(info->streams, "::$DATA");
 116 
 117         for (i=0;i<streams->num_streams;i++) {
 118                 info->streams[i+1].size          = streams->streams[i].size;
 119                 info->streams[i+1].alloc_size    = streams->streams[i].alloc_size;
 120                 if (strchr(streams->streams[i].name, ':') == NULL) {
 121                         info->streams[i+1].stream_name.s = talloc_asprintf(streams->streams, 
 122                                                                            ":%s:$DATA",
 123                                                                            streams->streams[i].name);
 124                 } else {
 125                         info->streams[i+1].stream_name.s = talloc_strdup(streams->streams, 
 126                                                                          streams->streams[i].name);
 127                 }
 128         }
 129 
 130         return NT_STATUS_OK;
 131 }
 132 
 133 
 134 /*
 135   fill in the stream information for a name
 136 */
 137 NTSTATUS pvfs_stream_info(struct pvfs_state *pvfs, struct pvfs_filename *name, int fd)
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 138 {
 139         struct xattr_DosStreams *streams;
 140         int i;
 141         NTSTATUS status;
 142 
 143         /* the NULL stream always exists */
 144         if (name->stream_name == NULL) {
 145                 name->stream_exists = true;
 146                 return NT_STATUS_OK;
 147         }
 148 
 149         streams = talloc(name, struct xattr_DosStreams);
 150         if (streams == NULL) {
 151                 return NT_STATUS_NO_MEMORY;
 152         }
 153 
 154         status = pvfs_streams_load(pvfs, name, fd, streams);
 155         if (!NT_STATUS_IS_OK(status)) {
 156                 talloc_free(streams);
 157                 return status;
 158         }
 159 
 160         for (i=0;i<streams->num_streams;i++) {
 161                 struct xattr_DosStream *s = &streams->streams[i];
 162                 if (stream_name_cmp(s->name, name->stream_name) == 0) {
 163                         name->dos.alloc_size = pvfs_round_alloc_size(pvfs, s->alloc_size);
 164                         name->st.st_size     = s->size;
 165                         name->stream_exists = true;
 166                         talloc_free(streams);
 167                         return NT_STATUS_OK;
 168                 }
 169         }
 170 
 171         talloc_free(streams);
 172 
 173         name->dos.alloc_size = 0;
 174         name->st.st_size     = 0;
 175         name->stream_exists = false;
 176 
 177         return NT_STATUS_OK;
 178 }
 179 
 180 
 181 /*
 182   update size information for a stream
 183 */
 184 static NTSTATUS pvfs_stream_update_size(struct pvfs_state *pvfs, struct pvfs_filename *name, int fd,
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 185                                         off_t size)
 186 {
 187         struct xattr_DosStreams *streams;
 188         int i;
 189         NTSTATUS status;
 190 
 191         streams = talloc(name, struct xattr_DosStreams);
 192         if (streams == NULL) {
 193                 return NT_STATUS_NO_MEMORY;
 194         }
 195 
 196         status = pvfs_streams_load(pvfs, name, fd, streams);
 197         if (!NT_STATUS_IS_OK(status)) {
 198                 ZERO_STRUCTP(streams);
 199         }
 200 
 201         for (i=0;i<streams->num_streams;i++) {
 202                 struct xattr_DosStream *s = &streams->streams[i];
 203                 if (stream_name_cmp(s->name, name->stream_name) == 0) {
 204                         s->size       = size;
 205                         s->alloc_size = pvfs_round_alloc_size(pvfs, size);
 206                         break;
 207                 }
 208         }
 209 
 210         if (i == streams->num_streams) {
 211                 struct xattr_DosStream *s;
 212                 streams->streams = talloc_realloc(streams, streams->streams, 
 213                                                     struct xattr_DosStream,
 214                                                     streams->num_streams+1);
 215                 if (streams->streams == NULL) {
 216                         talloc_free(streams);
 217                         return NT_STATUS_NO_MEMORY;
 218                 }
 219                 streams->num_streams++;
 220                 s = &streams->streams[i];
 221                 
 222                 s->flags      = XATTR_STREAM_FLAG_INTERNAL;
 223                 s->size       = size;
 224                 s->alloc_size = pvfs_round_alloc_size(pvfs, size);
 225                 s->name       = stream_name_normalise(streams, name->stream_name);
 226                 if (s->name == NULL) {
 227                         talloc_free(streams);
 228                         return NT_STATUS_NO_MEMORY;
 229                 }
 230         }
 231 
 232         status = pvfs_streams_save(pvfs, name, fd, streams);
 233         talloc_free(streams);
 234 
 235         return status;
 236 }
 237 
 238 
 239 /*
 240   rename a stream
 241 */
 242 NTSTATUS pvfs_stream_rename(struct pvfs_state *pvfs, struct pvfs_filename *name, int fd,
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 243                             const char *new_name)
 244 {
 245         struct xattr_DosStreams *streams;
 246         int i, found_old, found_new;
 247         NTSTATUS status;
 248 
 249         streams = talloc(name, struct xattr_DosStreams);
 250         if (streams == NULL) {
 251                 return NT_STATUS_NO_MEMORY;
 252         }
 253 
 254         new_name = stream_name_normalise(streams, new_name);
 255         if (new_name == NULL) {
 256                 return NT_STATUS_NO_MEMORY;
 257         }
 258 
 259         status = pvfs_streams_load(pvfs, name, fd, streams);
 260         if (!NT_STATUS_IS_OK(status)) {
 261                 ZERO_STRUCTP(streams);
 262         }
 263 
 264         /* the default stream always exists */
 265         if (strcmp(new_name, "") == 0 ||
 266             strcasecmp_m(new_name, ":$DATA") == 0) {
 267                 return NT_STATUS_OBJECT_NAME_COLLISION;         
 268         }
 269 
 270         /* try to find the old/new names in the list */
 271         found_old = found_new = -1;
 272         for (i=0;i<streams->num_streams;i++) {
 273                 struct xattr_DosStream *s = &streams->streams[i];
 274                 if (stream_name_cmp(s->name, new_name) == 0) {
 275                         found_new = i;
 276                 }
 277                 if (stream_name_cmp(s->name, name->stream_name) == 0) {
 278                         found_old = i;
 279                 }
 280         }
 281 
 282         if (found_old == -1) {
 283                 talloc_free(streams);
 284                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;         
 285         }
 286 
 287         if (found_new == -1) {
 288                 /* a simple rename */
 289                 struct xattr_DosStream *s = &streams->streams[found_old];
 290                 s->name = new_name;
 291         } else {
 292                 /* remove the old one and replace with the new one */
 293                 streams->streams[found_old].name = new_name;
 294                 memmove(&streams->streams[found_new],
 295                         &streams->streams[found_new+1],
 296                         sizeof(streams->streams[0]) *
 297                         (streams->num_streams - (found_new+1)));
 298         }
 299 
 300         status = pvfs_streams_save(pvfs, name, fd, streams);
 301         talloc_free(streams);
 302 
 303         return status;
 304 }
 305 
 306 
 307 /*
 308   create the xattr for a alternate data stream
 309 */
 310 NTSTATUS pvfs_stream_create(struct pvfs_state *pvfs, 
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 311                             struct pvfs_filename *name, 
 312                             int fd)
 313 {
 314         NTSTATUS status;
 315         status = pvfs_xattr_create(pvfs, name->full_name, fd, 
 316                                    XATTR_DOSSTREAM_PREFIX, name->stream_name);
 317         if (!NT_STATUS_IS_OK(status)) {
 318                 return status;
 319         }
 320         return pvfs_stream_update_size(pvfs, name, fd, 0);
 321 }
 322 
 323 /*
 324   delete the xattr for a alternate data stream
 325 */
 326 NTSTATUS pvfs_stream_delete(struct pvfs_state *pvfs, 
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 327                             struct pvfs_filename *name, 
 328                             int fd)
 329 {
 330         NTSTATUS status;
 331         struct xattr_DosStreams *streams;
 332         int i;
 333 
 334         status = pvfs_xattr_delete(pvfs, name->full_name, fd, 
 335                                    XATTR_DOSSTREAM_PREFIX, name->stream_name);
 336         if (!NT_STATUS_IS_OK(status)) {
 337                 return status;
 338         }
 339 
 340         streams = talloc(name, struct xattr_DosStreams);
 341         if (streams == NULL) {
 342                 return NT_STATUS_NO_MEMORY;
 343         }
 344 
 345         status = pvfs_streams_load(pvfs, name, fd, streams);
 346         if (!NT_STATUS_IS_OK(status)) {
 347                 talloc_free(streams);
 348                 return status;
 349         }
 350 
 351         for (i=0;i<streams->num_streams;i++) {
 352                 struct xattr_DosStream *s = &streams->streams[i];
 353                 if (stream_name_cmp(s->name, name->stream_name) == 0) {
 354                         memmove(s, s+1, (streams->num_streams - (i+1)) * sizeof(*s));
 355                         streams->num_streams--;
 356                         break;
 357                 }
 358         }
 359 
 360         status = pvfs_streams_save(pvfs, name, fd, streams);
 361         talloc_free(streams);
 362 
 363         return status;
 364 }
 365 
 366 /* 
 367    load a stream into a blob
 368 */
 369 static NTSTATUS pvfs_stream_load(struct pvfs_state *pvfs,
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 370                                  TALLOC_CTX *mem_ctx,
 371                                  struct pvfs_filename *name,
 372                                  int fd,
 373                                  size_t estimated_size,
 374                                  DATA_BLOB *blob)
 375 {
 376         NTSTATUS status;
 377 
 378         status = pvfs_xattr_load(pvfs, mem_ctx, name->full_name, fd, 
 379                                  XATTR_DOSSTREAM_PREFIX,
 380                                  name->stream_name, estimated_size, blob);
 381 
 382         if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
 383                 /* try with a case insensitive match */
 384                 struct xattr_DosStreams *streams;
 385                 int i;
 386 
 387                 streams = talloc(mem_ctx, struct xattr_DosStreams);
 388                 if (streams == NULL) {
 389                         return NT_STATUS_NO_MEMORY;
 390                 }
 391                 
 392                 status = pvfs_streams_load(pvfs, name, fd, streams);
 393                 if (!NT_STATUS_IS_OK(status)) {
 394                         talloc_free(streams);
 395                         return NT_STATUS_NOT_FOUND;
 396                 }
 397                 for (i=0;i<streams->num_streams;i++) {
 398                         struct xattr_DosStream *s = &streams->streams[i];
 399                         if (stream_name_cmp(s->name, name->stream_name) == 0) {
 400                                 status = pvfs_xattr_load(pvfs, mem_ctx, name->full_name, fd, 
 401                                                          XATTR_DOSSTREAM_PREFIX,
 402                                                          s->name, estimated_size, blob);
 403                                 talloc_free(streams);
 404                                 return status;
 405                         }
 406                 }
 407                 talloc_free(streams);
 408                 return NT_STATUS_NOT_FOUND;
 409         }
 410         
 411         return status;
 412 }
 413 
 414 /*
 415   the equvalent of pread() on a stream
 416 */
 417 ssize_t pvfs_stream_read(struct pvfs_state *pvfs,
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 418                          struct pvfs_file_handle *h, void *data, size_t count, off_t offset)
 419 {
 420         NTSTATUS status;
 421         DATA_BLOB blob;
 422         if (count == 0) {
 423                 return 0;
 424         }
 425         status = pvfs_stream_load(pvfs, h, h->name, h->fd, offset+count, &blob);
 426         if (!NT_STATUS_IS_OK(status)) {
 427                 errno = EIO;
 428                 return -1;
 429         }
 430         if (offset >= blob.length) {
 431                 data_blob_free(&blob);
 432                 return 0;
 433         }
 434         if (count > blob.length - offset) {
 435                 count = blob.length - offset;
 436         }
 437         memcpy(data, blob.data + offset, count);
 438         data_blob_free(&blob);
 439         return count;
 440 }
 441 
 442 
 443 /*
 444   the equvalent of pwrite() on a stream
 445 */
 446 ssize_t pvfs_stream_write(struct pvfs_state *pvfs,
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 447                           struct pvfs_file_handle *h, const void *data, size_t count, off_t offset)
 448 {
 449         NTSTATUS status;
 450         DATA_BLOB blob;
 451         if (count == 0) {
 452                 return 0;
 453         }
 454 
 455         if (count+offset > XATTR_MAX_STREAM_SIZE) {
 456                 if (!pvfs->ea_db || count+offset > XATTR_MAX_STREAM_SIZE_TDB) {
 457                         errno = ENOSPC;
 458                         return -1;
 459                 }
 460         }
 461 
 462         /* we have to load the existing stream, then modify, then save */
 463         status = pvfs_stream_load(pvfs, h, h->name, h->fd, offset+count, &blob);
 464         if (!NT_STATUS_IS_OK(status)) {
 465                 blob = data_blob(NULL, 0);
 466         }
 467         if (count+offset > blob.length) {
 468                 blob.data = talloc_realloc(blob.data, blob.data, uint8_t, count+offset);
 469                 if (blob.data == NULL) {
 470                         errno = ENOMEM;
 471                         return -1;
 472                 }
 473                 if (offset > blob.length) {
 474                         memset(blob.data+blob.length, 0, offset - blob.length);
 475                 }
 476                 blob.length = count+offset;
 477         }
 478         memcpy(blob.data + offset, data, count);
 479 
 480         status = pvfs_xattr_save(pvfs, h->name->full_name, h->fd, XATTR_DOSSTREAM_PREFIX,
 481                                  h->name->stream_name, &blob);
 482         if (!NT_STATUS_IS_OK(status)) {
 483                 data_blob_free(&blob);
 484                 /* getting this error mapping right is probably
 485                    not worth it */
 486                 errno = ENOSPC;
 487                 return -1;
 488         }
 489 
 490         status = pvfs_stream_update_size(pvfs, h->name, h->fd, blob.length);
 491 
 492         data_blob_free(&blob);
 493 
 494         if (!NT_STATUS_IS_OK(status)) {
 495                 errno = EIO;
 496                 return -1;
 497         }
 498 
 499         return count;
 500 }
 501 
 502 /*
 503   the equvalent of truncate() on a stream
 504 */
 505 NTSTATUS pvfs_stream_truncate(struct pvfs_state *pvfs,
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 506                               struct pvfs_filename *name, int fd, off_t length)
 507 {
 508         NTSTATUS status;
 509         DATA_BLOB blob;
 510 
 511         if (length > XATTR_MAX_STREAM_SIZE) {
 512                 if (!pvfs->ea_db || length > XATTR_MAX_STREAM_SIZE_TDB) {
 513                         return NT_STATUS_DISK_FULL;
 514                 }
 515         }
 516 
 517         /* we have to load the existing stream, then modify, then save */
 518         status = pvfs_stream_load(pvfs, name, name, fd, length, &blob);
 519         if (!NT_STATUS_IS_OK(status)) {
 520                 return status;
 521         }
 522         if (length <= blob.length) {
 523                 blob.length = length;
 524         } else if (length > blob.length) {
 525                 blob.data = talloc_realloc(blob.data, blob.data, uint8_t, length);
 526                 if (blob.data == NULL) {
 527                         return NT_STATUS_NO_MEMORY;
 528                 }
 529                 memset(blob.data+blob.length, 0, length - blob.length);
 530                 blob.length = length;
 531         }
 532 
 533         status = pvfs_xattr_save(pvfs, name->full_name, fd, XATTR_DOSSTREAM_PREFIX,
 534                                  name->stream_name, &blob);
 535         data_blob_free(&blob);
 536 
 537         if (NT_STATUS_IS_OK(status)) {
 538                 status = pvfs_stream_update_size(pvfs, name, fd, blob.length);
 539         }
 540 
 541         return status;
 542 }

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