| blob | b12a4606b3d5d8210a274f520a0447dadaa228ca |
1 /*
2 * linux/fs/hfs/file_hdr.c
3 *
4 * Copyright (C) 1995-1997 Paul H. Hargrove
5 * This file may be distributed under the terms of the GNU Public License.
6 *
7 * This file contains the file_ops and inode_ops for the metadata
8 * files under the AppleDouble and Netatalk representations.
9 *
10 * The source code distributions of Netatalk, versions 1.3.3b2 and
11 * 1.4b2, were used as a specification of the location and format of
12 * files used by Netatalk's afpd. No code from Netatalk appears in
13 * hfs_fs. hfs_fs is not a work ``derived'' from Netatalk in the
14 * sense of intellectual property law.
15 *
16 * "XXX" in a comment is a note to myself to consider changing something.
17 *
18 * In function preconditions the term "valid" applied to a pointer to
19 * a structure means that the pointer is non-NULL and the structure it
20 * points to has all fields initialized to consistent values.
21 *
22 * XXX: Note the reason that there is not bmap() for AppleDouble
23 * header files is that dynamic nature of their structure make it
24 * very difficult to safely mmap them. Maybe in the distant future
25 * I'll get bored enough to implement it.
26 */
29 #include <linux/hfs_fs_sb.h>
30 #include <linux/hfs_fs_i.h>
31 #include <linux/hfs_fs.h>
33 /*================ Forward declarations ================*/
40 /*================ Global variables ================*/
57 NULL /* lock - none */
58 };
76 header part has no disk block */
81 NULL /* revalidate */
82 };
94 },
101 }
102 };
113 },
119 }
120 };
132 },
139 }
140 };
142 /*================ File-local variables ================*/
147 /*================ File-local data types ================*/
150 hfs_lword_t magic;
151 hfs_lword_t version;
153 hfs_word_t entries;
155 };
157 /*================ File-local functions ================*/
159 /*
160 * dlength()
161 */
164 {
167 /* handle auto-sized entries */
175 }
183 }
192 }
193 }
195 }
197 /*
198 * hdr_build_meta()
199 */
203 {
214 }
222 }
223 }
225 /*
226 * dup_layout ()
227 */
229 {
237 }
238 }
240 }
242 /*
243 * init_layout()
244 */
247 {
256 }
262 }
264 /* Sort the 'order' array using an insertion sort */
273 }
274 }
275 }
277 /*
278 * adjust_forks()
279 */
282 {
296 }
297 }
298 }
300 /*
301 * get_dates()
302 */
305 {
307 /* AFPD compatible: use un*x times */
315 }
316 }
318 /*
319 * set_dates()
320 */
323 {
324 hfs_u32 tmp;
326 /* AFPD compatible: use un*x times */
331 }
338 }
343 }
349 }
356 }
361 }
362 }
363 }
365 /*
366 * hdr_read()
367 *
368 * This is the read field in the inode_operations structure for
369 * header files. The purpose is to transfer up to 'count' bytes
370 * from the file corresponding to 'inode', beginning at
371 * 'filp->offset' bytes into the file. The data is transfered to
372 * user-space at the address 'buf'. Returns the number of bytes
373 * successfully transfered.
374 */
375 /* XXX: what about the entry count changing on us? */
378 {
389 }
395 }
397 /* Adjust count to fit within the bounds of the file */
402 }
404 /* Handle the fixed-location portion */
413 }
421 }
424 }
426 /* Handle the actual data */
431 off_t limit;
433 /* stop reading if we run out of descriptors early */
436 }
438 /* find start and length of this entry */
442 /* Skip to next entry if this one is empty or isn't needed */
445 }
447 /* Pad with zeros to the start of this entry if needed */
452 }
458 }
461 }
463 /* locate and/or construct the data for this entry */
492 }
508 }
515 }
517 /* limit the transfer to the available data
518 of to the stated length of the entry. */
521 }
526 }
529 }
531 /* transfer the data */
543 }
544 }
549 }
551 /* Pad the file out with zeros */
556 }
558 done:
562 }
564 }
566 /*
567 * hdr_write()
568 *
569 * This is the write() entry in the file_operations structure for
570 * header files. The purpose is to transfer up to 'count' bytes
571 * to the file corresponding to 'inode' beginning at offset
572 * '*ppos' from user-space at the address 'buf'.
573 * The return value is the number of bytes actually transferred.
574 */
577 {
585 off_t pos;
590 }
593 }
599 }
602 /* Handle the 'magic', 'version', 'filler' and 'entries' fields */
611 }
618 /* XXX: should allocate slots dynamically */
622 }
628 }
631 }
633 /* We know for certain how many entries we have, so process them */
638 }
643 }
653 /* Handle possible size changes for the forks */
657 }
658 }
660 /* Handle the actual data */
665 off_t limit;
667 /* stop writing if we run out of descriptors early */
670 }
672 /* find start and length of this entry */
680 }
683 }
685 /* Trim length to avoid overlap with the next entry */
689 }
691 /* Skip to next entry if this one is empty or isn't needed */
694 }
696 /* Skip any padding that may exist between entries */
701 }
706 }
709 }
711 /* locate and/or construct the data for this entry */
716 #if 0
717 /* Can't yet write to the data fork via a header file, since there is the
718 * possibility to write via the data file, and the only locking is at the
719 * inode level.
720 */
723 #else
725 #endif
743 }
759 }
767 }
769 /* limit the transfer to the available data
770 of to the stated length of the entry. */
773 }
778 }
781 }
783 /* transfer the data from user space */
788 }
790 /* process the data */
801 }
807 }
808 }
826 }
836 }
837 }
838 }
848 }
851 }
857 }
863 }
865 /* Skip any padding at the end */
869 }
871 done:
877 }
879 }
881 /*
882 * hdr_truncate()
883 *
884 * This is the truncate field in the inode_operations structure for
885 * header files. The purpose is to allocate or release blocks as needed
886 * to satisfy a change in file length.
887 */
889 {
890 /*struct inode *inode = dentry->d_inode;*/
898 }
905 hfs_u32 offset;
909 }
913 #if 0
914 /* Can't yet truncate the data fork via a header file, since there is the
915 * possibility to truncate via the data file, and the only locking is at
916 * the inode level.
917 */
920 #endif
923 }
929 }
935 }
940 }
941 }
942 }