source4/ntvfs/posix/pvfs_streams.c

   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 :$DATA suffix if there is one
  28   Note: this returns the existing pointer to the name if the name does
  29         not need normalising
  30  */
  31 static const char *stream_name_normalise(TALLOC_CTX *ctx, const char *name)
  32 {
  33         const char *c = strchr_m(name, ':');
  34         if (c == NULL || strcasecmp_m(c, ":$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 $DATA extension
  42  */
  43 static int stream_name_cmp(const char *name1, const char *name2)
  44 {
  45         const char *c1, *c2;
  46         int l1, l2, ret;
  47         c1 = strchr_m(name1, ':');
  48         c2 = strchr_m(name2, ':');
  49
  50         /* check the first part is the same */
  51         l1 = c1?(c1 - name1):strlen(name1);
  52         l2 = c2?(c2 - name2):strlen(name2);
  53         if (l1 != l2) {
  54                 return l1 - l2;
  55         }
  56         ret = strncasecmp_m(name1, name2, l1);
  57         if (ret != 0) {
  58                 return ret;
  59         }
  60
  61         /* the first parts are the same, check the suffix */
  62         if (c1 && c2) {
  63                 return strcasecmp_m(c1, c2);
  64         }
  65
  66         if (c1) {
  67                 return strcasecmp_m(c1, ":$DATA");
  68         }
  69         if (c2) {
  70                 return strcasecmp_m(c2, ":$DATA");
  71         }
  72
  73         /* neither names have a suffix */
  74         return 0;
  75 }
  76
  77
  78 /*
  79   return the list of file streams for RAW_FILEINFO_STREAM_INFORMATION
  80 */
  81 NTSTATUS pvfs_stream_information(struct pvfs_state *pvfs,
  82                                  TALLOC_CTX *mem_ctx,
  83                                  struct pvfs_filename *name, int fd,
  84                                  struct stream_information *info)
  85 {
  86         struct xattr_DosStreams *streams;
  87         int i;
  88         NTSTATUS status;
  89
  90         /* directories don't have streams */
  91         if (name->dos.attrib & FILE_ATTRIBUTE_DIRECTORY) {
  92                 info->num_streams = 0;
  93                 info->streams = NULL;
  94                 return NT_STATUS_OK;
  95         }
  96
  97         streams = talloc(mem_ctx, struct xattr_DosStreams);
  98         if (streams == NULL) {
  99                 return NT_STATUS_NO_MEMORY;
 100         }
 101
 102         status = pvfs_streams_load(pvfs, name, fd, streams);
 103         if (!NT_STATUS_IS_OK(status)) {
 104                 ZERO_STRUCTP(streams);
 105         }
 106
 107         info->num_streams = streams->num_streams+1;
 108         info->streams = talloc_array(mem_ctx, struct stream_struct, info->num_streams);
 109         if (!info->streams) {
 110                 return NT_STATUS_NO_MEMORY;
 111         }
 112
 113         info->streams[0].size          = name->st.st_size;
 114         info->streams[0].alloc_size    = name->dos.alloc_size;
 115         info->streams[0].stream_name.s = talloc_strdup(info->streams, "::$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)
 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,
 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,
 243                             const char *new_name, bool overwrite)
 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                 if (!overwrite) {
 293                         return NT_STATUS_OBJECT_NAME_COLLISION;
 294                 }
 295                 if (found_old != found_new) {
 296                         /* remove the old one and replace with the new one */
 297                         streams->streams[found_old].name = new_name;
 298                         memmove(&streams->streams[found_new],
 299                                 &streams->streams[found_new+1],
 300                                 sizeof(streams->streams[0]) *
 301                                 (streams->num_streams - (found_new+1)));
 302                         streams->num_streams--;
 303                 }
 304         }
 305
 306         status = pvfs_streams_save(pvfs, name, fd, streams);
 307
 308         if (NT_STATUS_IS_OK(status)) {
 309
 310                 /* update the in-memory copy of the name of the open file */
 311                 talloc_free(name->stream_name);
 312                 name->stream_name = talloc_strdup(name, new_name);
 313
 314                 talloc_free(streams);
 315         }
 316
 317         return status;
 318 }
 319
 320
 321 /*
 322   create the xattr for a alternate data stream
 323 */
 324 NTSTATUS pvfs_stream_create(struct pvfs_state *pvfs,
 325                             struct pvfs_filename *name,
 326                             int fd)
 327 {
 328         NTSTATUS status;
 329         status = pvfs_xattr_create(pvfs, name->full_name, fd,
 330                                    XATTR_DOSSTREAM_PREFIX, name->stream_name);
 331         if (!NT_STATUS_IS_OK(status)) {
 332                 return status;
 333         }
 334         return pvfs_stream_update_size(pvfs, name, fd, 0);
 335 }
 336
 337 /*
 338   delete the xattr for a alternate data stream
 339 */
 340 NTSTATUS pvfs_stream_delete(struct pvfs_state *pvfs,
 341                             struct pvfs_filename *name,
 342                             int fd)
 343 {
 344         NTSTATUS status;
 345         struct xattr_DosStreams *streams;
 346         int i;
 347
 348         status = pvfs_xattr_delete(pvfs, name->full_name, fd,
 349                                    XATTR_DOSSTREAM_PREFIX, name->stream_name);
 350         if (!NT_STATUS_IS_OK(status)) {
 351                 return status;
 352         }
 353
 354         streams = talloc(name, struct xattr_DosStreams);
 355         if (streams == NULL) {
 356                 return NT_STATUS_NO_MEMORY;
 357         }
 358
 359         status = pvfs_streams_load(pvfs, name, fd, streams);
 360         if (!NT_STATUS_IS_OK(status)) {
 361                 talloc_free(streams);
 362                 return status;
 363         }
 364
 365         for (i=0;i<streams->num_streams;i++) {
 366                 struct xattr_DosStream *s = &streams->streams[i];
 367                 if (stream_name_cmp(s->name, name->stream_name) == 0) {
 368                         memmove(s, s+1, (streams->num_streams - (i+1)) * sizeof(*s));
 369                         streams->num_streams--;
 370                         break;
 371                 }
 372         }
 373
 374         status = pvfs_streams_save(pvfs, name, fd, streams);
 375         talloc_free(streams);
 376
 377         return status;
 378 }
 379
 380 /*
 381    load a stream into a blob
 382 */
 383 static NTSTATUS pvfs_stream_load(struct pvfs_state *pvfs,
 384                                  TALLOC_CTX *mem_ctx,
 385                                  struct pvfs_filename *name,
 386                                  int fd,
 387                                  size_t estimated_size,
 388                                  DATA_BLOB *blob)
 389 {
 390         NTSTATUS status;
 391
 392         status = pvfs_xattr_load(pvfs, mem_ctx, name->full_name, fd,
 393                                  XATTR_DOSSTREAM_PREFIX,
 394                                  name->stream_name, estimated_size, blob);
 395
 396         if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
 397                 /* try with a case insensitive match */
 398                 struct xattr_DosStreams *streams;
 399                 int i;
 400
 401                 streams = talloc(mem_ctx, struct xattr_DosStreams);
 402                 if (streams == NULL) {
 403                         return NT_STATUS_NO_MEMORY;
 404                 }
 405
 406                 status = pvfs_streams_load(pvfs, name, fd, streams);
 407                 if (!NT_STATUS_IS_OK(status)) {
 408                         talloc_free(streams);
 409                         return NT_STATUS_NOT_FOUND;
 410                 }
 411                 for (i=0;i<streams->num_streams;i++) {
 412                         struct xattr_DosStream *s = &streams->streams[i];
 413                         if (stream_name_cmp(s->name, name->stream_name) == 0) {
 414                                 status = pvfs_xattr_load(pvfs, mem_ctx, name->full_name, fd,
 415                                                          XATTR_DOSSTREAM_PREFIX,
 416                                                          s->name, estimated_size, blob);
 417                                 talloc_free(streams);
 418                                 return status;
 419                         }
 420                 }
 421                 talloc_free(streams);
 422                 return NT_STATUS_NOT_FOUND;
 423         }
 424
 425         return status;
 426 }
 427
 428 /*
 429   the equvalent of pread() on a stream
 430 */
 431 ssize_t pvfs_stream_read(struct pvfs_state *pvfs,
 432                          struct pvfs_file_handle *h, void *data, size_t count, off_t offset)
 433 {
 434         NTSTATUS status;
 435         DATA_BLOB blob;
 436         if (count == 0) {
 437                 return 0;
 438         }
 439         status = pvfs_stream_load(pvfs, h, h->name, h->fd, offset+count, &blob);
 440         if (!NT_STATUS_IS_OK(status)) {
 441                 errno = EIO;
 442                 return -1;
 443         }
 444         if (offset >= blob.length) {
 445                 data_blob_free(&blob);
 446                 return 0;
 447         }
 448         if (count > blob.length - offset) {
 449                 count = blob.length - offset;
 450         }
 451         memcpy(data, blob.data + offset, count);
 452         data_blob_free(&blob);
 453         return count;
 454 }
 455
 456
 457 /*
 458   the equvalent of pwrite() on a stream
 459 */
 460 ssize_t pvfs_stream_write(struct pvfs_state *pvfs,
 461                           struct pvfs_file_handle *h, const void *data, size_t count, off_t offset)
 462 {
 463         NTSTATUS status;
 464         DATA_BLOB blob;
 465         if (count == 0) {
 466                 return 0;
 467         }
 468
 469         if (count+offset > XATTR_MAX_STREAM_SIZE) {
 470                 if (!pvfs->ea_db || count+offset > XATTR_MAX_STREAM_SIZE_TDB) {
 471                         errno = ENOSPC;
 472                         return -1;
 473                 }
 474         }
 475
 476         /* we have to load the existing stream, then modify, then save */
 477         status = pvfs_stream_load(pvfs, h, h->name, h->fd, offset+count, &blob);
 478         if (!NT_STATUS_IS_OK(status)) {
 479                 blob = data_blob(NULL, 0);
 480         }
 481         if (count+offset > blob.length) {
 482                 blob.data = talloc_realloc(blob.data, blob.data, uint8_t, count+offset);
 483                 if (blob.data == NULL) {
 484                         errno = ENOMEM;
 485                         return -1;
 486                 }
 487                 if (offset > blob.length) {
 488                         memset(blob.data+blob.length, 0, offset - blob.length);
 489                 }
 490                 blob.length = count+offset;
 491         }
 492         memcpy(blob.data + offset, data, count);
 493
 494         status = pvfs_xattr_save(pvfs, h->name->full_name, h->fd, XATTR_DOSSTREAM_PREFIX,
 495                                  h->name->stream_name, &blob);
 496         if (!NT_STATUS_IS_OK(status)) {
 497                 data_blob_free(&blob);
 498                 /* getting this error mapping right is probably
 499                    not worth it */
 500                 errno = ENOSPC;
 501                 return -1;
 502         }
 503
 504         status = pvfs_stream_update_size(pvfs, h->name, h->fd, blob.length);
 505
 506         data_blob_free(&blob);
 507
 508         if (!NT_STATUS_IS_OK(status)) {
 509                 errno = EIO;
 510                 return -1;
 511         }
 512
 513         return count;
 514 }
 515
 516 /*
 517   the equvalent of truncate() on a stream
 518 */
 519 NTSTATUS pvfs_stream_truncate(struct pvfs_state *pvfs,
 520                               struct pvfs_filename *name, int fd, off_t length)
 521 {
 522         NTSTATUS status;
 523         DATA_BLOB blob;
 524
 525         if (length > XATTR_MAX_STREAM_SIZE) {
 526                 if (!pvfs->ea_db || length > XATTR_MAX_STREAM_SIZE_TDB) {
 527                         return NT_STATUS_DISK_FULL;
 528                 }
 529         }
 530
 531         /* we have to load the existing stream, then modify, then save */
 532         status = pvfs_stream_load(pvfs, name, name, fd, length, &blob);
 533         if (!NT_STATUS_IS_OK(status)) {
 534                 return status;
 535         }
 536         if (length <= blob.length) {
 537                 blob.length = length;
 538         } else if (length > blob.length) {
 539                 blob.data = talloc_realloc(blob.data, blob.data, uint8_t, length);
 540                 if (blob.data == NULL) {
 541                         return NT_STATUS_NO_MEMORY;
 542                 }
 543                 memset(blob.data+blob.length, 0, length - blob.length);
 544                 blob.length = length;
 545         }
 546
 547         status = pvfs_xattr_save(pvfs, name->full_name, fd, XATTR_DOSSTREAM_PREFIX,
 548                                  name->stream_name, &blob);
 549
 550         if (NT_STATUS_IS_OK(status)) {
 551                 status = pvfs_stream_update_size(pvfs, name, fd, blob.length);
 552         }
 553         data_blob_free(&blob);
 554
 555         return status;
 556 }