1 /* ----------------------------------------------------------------------- *
2 *
3 * Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, Inc., 53 Temple Place Ste 330,
8 * Boston MA 02111-1307, USA; either version 2 of the License, or
9 * (at your option) any later version; incorporated herein by reference.
10 *
11 * ----------------------------------------------------------------------- */
12
13 /*
14 * searchdir.c
15 *
16 * Search a FAT directory for a particular pre-mangled filename.
17 * Copies the directory entry into direntry and returns the starting cluster
18 * if found; returns -2 on not found, -1 on error, 0 on empty file.
19 */
20
21 #include <string.h>
22 #include "libfatint.h"
23
libfat_searchdir(struct libfat_filesystem * fs,int32_t dirclust,const void * name,struct libfat_direntry * direntry)24 int32_t libfat_searchdir(struct libfat_filesystem *fs, int32_t dirclust,
25 const void *name, struct libfat_direntry *direntry)
26 {
27 struct fat_dirent *dep;
28 int nent;
29 libfat_sector_t s = libfat_clustertosector(fs, dirclust);
30
31 while (1) {
32 if (s == 0)
33 return -2; /* Not found */
34 else if (s == (libfat_sector_t) - 1)
35 return -1; /* Error */
36
37 dep = libfat_get_sector(fs, s);
38 if (!dep)
39 return -1; /* Read error */
40
41 for (nent = 0; nent < LIBFAT_SECTOR_SIZE;
42 nent += sizeof(struct fat_dirent)) {
43 if (!memcmp(dep->name, name, 11)) {
44 if (direntry) {
45 memcpy(direntry->entry, dep, sizeof(*dep));
46 direntry->sector = s;
47 direntry->offset = nent;
48 }
49 if (read32(&dep->size) == 0)
50 return 0; /* An empty file has no clusters */
51 else
52 return read16(&dep->clustlo) +
53 (read16(&dep->clusthi) << 16);
54 }
55
56 if (dep->name[0] == 0)
57 return -2; /* Hit high water mark */
58
59 dep++;
60 }
61
62 s = libfat_nextsector(fs, s);
63 }
64 }
65