1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * collate.c - NTFS kernel collation handling. Part of the Linux-NTFS project.
4 *
5 * Copyright (c) 2004 Anton Altaparmakov
6 */
7
8 #include "collate.h"
9 #include "debug.h"
10 #include "ntfs.h"
11
12 static int ntfs_collate_binary(ntfs_volume *vol,
13 const void *data1, const int data1_len,
14 const void *data2, const int data2_len)
15 {
16 int rc;
17
18 ntfs_debug("Entering.");
19 rc = memcmp(data1, data2, min(data1_len, data2_len));
20 if (!rc && (data1_len != data2_len)) {
21 if (data1_len < data2_len)
22 rc = -1;
23 else
24 rc = 1;
25 }
26 ntfs_debug("Done, returning %i", rc);
27 return rc;
28 }
29
30 static int ntfs_collate_ntofs_ulong(ntfs_volume *vol,
31 const void *data1, const int data1_len,
32 const void *data2, const int data2_len)
33 {
34 int rc;
35 u32 d1, d2;
36
37 ntfs_debug("Entering.");
38 // FIXME: We don't really want to bug here.
39 BUG_ON(data1_len != data2_len);
40 BUG_ON(data1_len != 4);
41 d1 = le32_to_cpup(data1);
42 d2 = le32_to_cpup(data2);
43 if (d1 < d2)
44 rc = -1;
45 else {
46 if (d1 == d2)
47 rc = 0;
48 else
49 rc = 1;
50 }
51 ntfs_debug("Done, returning %i", rc);
52 return rc;
53 }
54
55 typedef int (*ntfs_collate_func_t)(ntfs_volume *, const void *, const int,
56 const void *, const int);
57
58 static ntfs_collate_func_t ntfs_do_collate0x0[3] = {
59 ntfs_collate_binary,
60 NULL/*ntfs_collate_file_name*/,
61 NULL/*ntfs_collate_unicode_string*/,
62 };
63
64 static ntfs_collate_func_t ntfs_do_collate0x1[4] = {
65 ntfs_collate_ntofs_ulong,
66 NULL/*ntfs_collate_ntofs_sid*/,
67 NULL/*ntfs_collate_ntofs_security_hash*/,
68 NULL/*ntfs_collate_ntofs_ulongs*/,
69 };
70
71 /**
72 * ntfs_collate - collate two data items using a specified collation rule
73 * @vol: ntfs volume to which the data items belong
74 * @cr: collation rule to use when comparing the items
75 * @data1: first data item to collate
76 * @data1_len: length in bytes of @data1
77 * @data2: second data item to collate
78 * @data2_len: length in bytes of @data2
79 *
80 * Collate the two data items @data1 and @data2 using the collation rule @cr
81 * and return -1, 0, ir 1 if @data1 is found, respectively, to collate before,
82 * to match, or to collate after @data2.
83 *
84 * For speed we use the collation rule @cr as an index into two tables of
85 * function pointers to call the appropriate collation function.
86 */
87 int ntfs_collate(ntfs_volume *vol, COLLATION_RULE cr,
88 const void *data1, const int data1_len,
89 const void *data2, const int data2_len) {
90 int i;
91
92 ntfs_debug("Entering.");
93 /*
94 * FIXME: At the moment we only support COLLATION_BINARY and
95 * COLLATION_NTOFS_ULONG, so we BUG() for everything else for now.
96 */
97 BUG_ON(cr != COLLATION_BINARY && cr != COLLATION_NTOFS_ULONG);
98 i = le32_to_cpu(cr);
99 BUG_ON(i < 0);
100 if (i <= 0x02)
101 return ntfs_do_collate0x0[i](vol, data1, data1_len,
102 data2, data2_len);
103 BUG_ON(i < 0x10);
104 i -= 0x10;
105 if (likely(i <= 3))
106 return ntfs_do_collate0x1[i](vol, data1, data1_len,
107 data2, data2_len);
108 BUG();
109 return 0;
110 }