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(p: data1, q: 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(p: data1); |
42 | d2 = le32_to_cpup(p: 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 | } |
111 | |