| blob | 9479fab08c90d2cd7a0541e39c02d765c22e3709 |
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 {
309 }
311 /*
312 * set_dates()
313 */
316 {
317 hfs_u32 tmp;
323 }
330 }
335 }
336 }
338 /*
339 * hdr_read()
340 *
341 * This is the read field in the inode_operations structure for
342 * header files. The purpose is to transfer up to 'count' bytes
343 * from the file corresponding to 'inode', beginning at
344 * 'filp->offset' bytes into the file. The data is transfered to
345 * user-space at the address 'buf'. Returns the number of bytes
346 * successfully transfered.
347 */
348 /* XXX: what about the entry count changing on us? */
351 {
362 }
368 }
370 /* Adjust count to fit within the bounds of the file */
375 }
377 /* Handle the fixed-location portion */
386 }
394 }
397 }
399 /* Handle the actual data */
404 off_t limit;
406 /* stop reading if we run out of descriptors early */
409 }
411 /* find start and length of this entry */
415 /* Skip to next entry if this one is empty or isn't needed */
418 }
420 /* Pad with zeros to the start of this entry if needed */
425 }
431 }
434 }
436 /* locate and/or construct the data for this entry */
465 }
481 }
488 }
490 /* limit the transfer to the available data
491 of to the stated length of the entry. */
494 }
499 }
502 }
504 /* transfer the data */
516 }
517 }
522 }
524 /* Pad the file out with zeros */
529 }
531 done:
536 }
538 }
540 /*
541 * hdr_write()
542 *
543 * This is the write() entry in the file_operations structure for
544 * header files. The purpose is to transfer up to 'count' bytes
545 * to the file corresponding to 'inode' beginning at offset
546 * '*ppos' from user-space at the address 'buf'.
547 * The return value is the number of bytes actually transferred.
548 */
551 {
559 off_t pos;
564 }
567 }
573 }
576 /* Handle the 'magic', 'version', 'filler' and 'entries' fields */
585 }
592 /* XXX: should allocate slots dynamically */
596 }
602 }
605 }
607 /* We know for certain how many entries we have, so process them */
612 }
617 }
627 /* Handle possible size changes for the forks */
631 }
632 }
634 /* Handle the actual data */
639 off_t limit;
641 /* stop writing if we run out of descriptors early */
644 }
646 /* find start and length of this entry */
654 }
657 }
659 /* Trim length to avoid overlap with the next entry */
663 }
665 /* Skip to next entry if this one is empty or isn't needed */
668 }
670 /* Skip any padding that may exist between entries */
675 }
680 }
683 }
685 /* locate and/or construct the data for this entry */
690 #if 0
691 /* Can't yet write to the data fork via a header file, since there is the
692 * possibility to write via the data file, and the only locking is at the
693 * inode level.
694 */
697 #else
699 #endif
717 }
733 }
741 }
743 /* limit the transfer to the available data
744 of to the stated length of the entry. */
747 }
752 }
755 }
757 /* transfer the data from user space */
762 }
764 /* process the data */
775 }
781 }
782 }
800 }
810 }
811 }
812 }
822 }
825 }
831 }
837 }
839 /* Skip any padding at the end */
843 }
845 done:
852 }
854 }
856 /*
857 * hdr_truncate()
858 *
859 * This is the truncate field in the inode_operations structure for
860 * header files. The purpose is to allocate or release blocks as needed
861 * to satisfy a change in file length.
862 */
864 {
872 }
879 hfs_u32 offset;
883 }
887 #if 0
888 /* Can't yet truncate the data fork via a header file, since there is the
889 * possibility to truncate via the data file, and the only locking is at
890 * the inode level.
891 */
894 #endif
897 }
903 }
909 }
914 }
915 }
916 }