1 /* gstdio-private.c - private glib functions for gstdio.c
2 *
3 * Copyright 2004 Tor Lillqvist
4 * Copyright 2018 Руслан Ижбулатов
5 *
6 * SPDX-License-Identifier: LGPL-2.1-or-later
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this library; if not, see <http://www.gnu.org/licenses/>.
20 */
21
22 /* Strips "\\\\?\\" extended prefix or
23 * "\\??\\" NT Object Manager prefix from
24 * @str in-place, using memmove.
25 * @str_size must point to the size of @str
26 * in gunichar2s, including NUL-terminator
27 * (if @str is NUL-terminated; it doesn't have to be).
28 * On return @str_size will correctly reflect changes
29 * in @str size (if any).
30 * Returns TRUE if @str was modified.
31 */
32 static gboolean
33 _g_win32_strip_extended_ntobjm_prefix (gunichar2 *str,
34 gsize *str_size)
35 {
36 const wchar_t *extended_prefix = L"\\\\?\\";
37 const gsize extended_prefix_len = wcslen (extended_prefix);
38 const gsize extended_prefix_len_bytes = sizeof (gunichar2) * extended_prefix_len;
39 const gsize extended_prefix_with_drive_len_bytes = sizeof (gunichar2) * (extended_prefix_len + 2);
40 const wchar_t *ntobjm_prefix = L"\\??\\";
41 const gsize ntobjm_prefix_len = wcslen (ntobjm_prefix);
42 const gsize ntobjm_prefix_len_bytes = sizeof (gunichar2) * ntobjm_prefix_len;
43 const gsize ntobjm_prefix_with_drive_len_bytes = sizeof (gunichar2) * (ntobjm_prefix_len + 2);
44 gboolean do_move = FALSE;
45 gsize move_shift = 0;
46
47 if ((*str_size) * sizeof (gunichar2) > extended_prefix_with_drive_len_bytes &&
48 memcmp (str,
49 extended_prefix,
50 extended_prefix_len_bytes) == 0 &&
51 iswascii (str[extended_prefix_len]) &&
52 iswalpha (str[extended_prefix_len]) &&
53 str[extended_prefix_len + 1] == L':')
54 {
55 do_move = TRUE;
56 move_shift = extended_prefix_len;
57 }
58 else if ((*str_size) * sizeof (gunichar2) > ntobjm_prefix_with_drive_len_bytes &&
59 memcmp (str,
60 ntobjm_prefix,
61 ntobjm_prefix_len_bytes) == 0 &&
62 iswascii (str[ntobjm_prefix_len]) &&
63 iswalpha (str[ntobjm_prefix_len]) &&
64 str[ntobjm_prefix_len + 1] == L':')
65 {
66 do_move = TRUE;
67 move_shift = ntobjm_prefix_len;
68 }
69
70 if (do_move)
71 {
72 *str_size -= move_shift;
73 memmove (str,
74 str + move_shift,
75 (*str_size) * sizeof (gunichar2));
76 }
77
78 return do_move;
79 }
80
81 static int
82 _g_win32_copy_and_maybe_terminate (const guchar *data,
83 gsize in_to_copy,
84 gunichar2 *buf,
85 gsize buf_size,
86 gunichar2 **alloc_buf,
87 gboolean terminate)
88 {
89 gsize to_copy = in_to_copy;
90 /* Number of bytes we can use to add extra zeroes for NUL-termination.
91 * 0 means that we can destroy up to 2 bytes of data,
92 * 1 means that we can destroy up to 1 byte of data,
93 * 2 means that we do not perform destructive NUL-termination
94 */
95 gsize extra_bytes = terminate ? 2 : 0;
96 char *buf_in_chars;
97
98 if (to_copy == 0)
99 return 0;
100
101 /* 2 bytes is sizeof (wchar_t), for an extra NUL-terminator. */
102 if (buf)
103 {
104 if (to_copy >= buf_size)
105 {
106 extra_bytes = 0;
107 to_copy = buf_size;
108 }
109 else if (to_copy > buf_size - 2)
110 {
111 extra_bytes = 1;
112 }
113
114 memcpy (buf, data, to_copy);
115 }
116 else
117 {
118 /* Note that SubstituteNameLength is USHORT, so to_copy + 2, being
119 * gsize, never overflows.
120 */
121 *alloc_buf = g_malloc (to_copy + extra_bytes);
122 memcpy (*alloc_buf, data, to_copy);
123 }
124
125 if (!terminate)
126 return to_copy;
127
128 if (buf)
129 buf_in_chars = (char *) buf;
130 else
131 buf_in_chars = (char *) *alloc_buf;
132
133 if (to_copy >= 2 && buf_in_chars[to_copy - 2] == 0 &&
134 buf_in_chars[to_copy - 1] == 0)
135 {
136 /* Fully NUL-terminated, do nothing */
137 }
138 else if ((to_copy == 1 || buf_in_chars[to_copy - 2] != 0) &&
139 buf_in_chars[to_copy - 1] == 0)
140 {
141 /* Have one zero, try to add another one */
142 if (extra_bytes > 0)
143 {
144 /* Append trailing zero */
145 buf_in_chars[to_copy] = 0;
146 /* Be precise about the number of bytes we return */
147 to_copy += 1;
148 }
149 else if (to_copy >= 2)
150 {
151 /* No space for appending, destroy one byte */
152 buf_in_chars[to_copy - 2] = 0;
153 }
154 /* else there's no space at all (to_copy == 1), do nothing */
155 }
156 else if (extra_bytes > 0 || to_copy >= 2)
157 {
158 buf_in_chars[to_copy - 2 + extra_bytes] = 0;
159 buf_in_chars[to_copy - 1 + extra_bytes] = 0;
160 to_copy += extra_bytes;
161 }
162 else /* extra_bytes == 0 && to_copy == 1 */
163 {
164 buf_in_chars[0] = 0;
165 }
166
167 return to_copy;
168 }