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W32: Don't always strip path prefixes

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Extended path prefix looks like "\\?\",
and NT object path prefix looks like "\??\".
Strip them only if they are followed by a character
(any character) and a colon (:), indicating that
it's a DOS path with a drive.
Otherwise stripping such prefix might result in a patch
that looks like a relative path.

For example, "\\?\Volume{GUID}\" becomes "Volume{GUID}\",
which is a valid directory name.

Currently it's up to the user to make sense of such paths.
This commit is contained in:
Руслан Ижбулатов 2018-08-08 22:22:08 +00:00
parent b7fba1a5e3
commit 05fdd09740
2 changed files with 116 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
glib/gstdio-private.c Normal file
View File

@ -0,0 +1,77 @@
/* gstdio-private.c - private glib functions for gstdio.c
*
* Copyright 2004 Tor Lillqvist
* Copyright 2018 Руслан Ижбулатов
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/* Strips "\\\\?\\" extended prefix or
* "\\??\\" NT Object Manager prefix from
* @str in-place, using memmove.
* @str_size must point to the size of @str
* in gunichar2s, including NUL-terminator
* (if @str is NUL-terminated; it doesn't have to be).
* On return @str_size will correctly reflect changes
* in @str size (if any).
* Returns TRUE if @str was modified.
*/
static gboolean
_g_win32_strip_extended_ntobjm_prefix (gunichar2 *str,
gsize *str_size)
{
const wchar_t *extended_prefix = L"\\\\?\\";
const gsize extended_prefix_len = wcslen (extended_prefix);
const gsize extended_prefix_len_bytes = sizeof (gunichar2) * extended_prefix_len;
const gsize extended_prefix_with_drive_len_bytes = sizeof (gunichar2) * (extended_prefix_len + 2);
const wchar_t *ntobjm_prefix = L"\\??\\";
const gsize ntobjm_prefix_len = wcslen (ntobjm_prefix);
const gsize ntobjm_prefix_len_bytes = sizeof (gunichar2) * ntobjm_prefix_len;
const gsize ntobjm_prefix_with_drive_len_bytes = sizeof (gunichar2) * (ntobjm_prefix_len + 2);
gboolean do_move = FALSE;
gsize move_shift = 0;
if ((*str_size) * sizeof (gunichar2) > extended_prefix_with_drive_len_bytes &&
memcmp (str,
extended_prefix,
extended_prefix_len_bytes) == 0 &&
iswascii (str[extended_prefix_len]) &&
iswalpha (str[extended_prefix_len]) &&
str[extended_prefix_len + 1] == L':')
{
do_move = TRUE;
move_shift = extended_prefix_len;
}
else if ((*str_size) * sizeof (gunichar2) > ntobjm_prefix_with_drive_len_bytes &&
memcmp (str,
ntobjm_prefix,
ntobjm_prefix_len_bytes) == 0 &&
iswascii (str[ntobjm_prefix_len]) &&
iswalpha (str[ntobjm_prefix_len]) &&
str[ntobjm_prefix_len + 1] == L':')
{
do_move = TRUE;
move_shift = ntobjm_prefix_len;
}
if (do_move)
{
*str_size -= move_shift;
memmove (str,
str + move_shift,
(*str_size) * sizeof (gunichar2));
}
return do_move;
}

67
glib/gstdio.c
View File

@ -121,6 +121,8 @@ w32_error_to_errno (DWORD error_code)
}
}
#include "gstdio-private.c"
static int
_g_win32_stat_utf16_no_trailing_slashes (const gunichar2 *filename,
int fd,
@ -259,15 +261,11 @@ _g_win32_stat_utf16_no_trailing_slashes (const gunichar2 *filename,
if (new_len > 0)
{
const wchar_t *extended_prefix = L"\\\\?\\";
const gsize extended_prefix_len = wcslen (extended_prefix);
const gsize extended_prefix_len_bytes = sizeof (wchar_t) * extended_prefix_len;
/* Pretend that new_len doesn't count the terminating NUL char,
* and ask for a bit more space than is needed.
* and ask for a bit more space than is needed, and allocate even more.
*/
filename_target_len = new_len + 5;
filename_target = g_malloc (filename_target_len * sizeof (wchar_t));
filename_target_len = new_len + 3;
filename_target = g_malloc ((filename_target_len + 1) * sizeof (wchar_t));
new_len = GetFinalPathNameByHandleW (file_handle,
filename_target,
@ -284,17 +282,32 @@ _g_win32_stat_utf16_no_trailing_slashes (const gunichar2 *filename,
error_code = ERROR_BUFFER_OVERFLOW;
g_clear_pointer (&filename_target, g_free);
}
/* GetFinalPathNameByHandle() is documented to return extended paths,
* strip the extended prefix.
*/
else if (new_len > extended_prefix_len &&
memcmp (filename_target, extended_prefix, extended_prefix_len_bytes) == 0)
else if (new_len == 0)
{
new_len -= extended_prefix_len;
memmove (filename_target,
filename_target + extended_prefix_len,
(new_len + 1) * sizeof (wchar_t));
g_clear_pointer (&filename_target, g_free);
}
/* GetFinalPathNameByHandle() is documented to return extended paths,
* strip the extended prefix, if it is followed by a drive letter
* and a colon. Otherwise keep it (the path could be
* \\\\?\\Volume{GUID}\\ - it's only usable in extended form).
*/
else if (new_len > 0)
{
gsize len = new_len;
/* Account for NUL-terminator maybe not being counted.
* This is why we overallocated earlier.
*/
if (filename_target[len] != L'\0')
{
len++;
filename_target[len] = L'\0';
}
_g_win32_strip_extended_ntobjm_prefix (filename_target, &len);
new_len = len;
}
}
if (new_len == 0)
@ -513,10 +526,8 @@ _g_win32_readlink_utf16 (const gunichar2 *filename,
gunichar2 *buf,
gsize buf_size)
{
const wchar_t *ntobjm_prefix = L"\\??\\";
const gsize ntobjm_prefix_len_unichar2 = wcslen (ntobjm_prefix);
const gsize ntobjm_prefix_len_bytes = sizeof (gunichar2) * ntobjm_prefix_len_unichar2;
int result = _g_win32_readlink_utf16_raw (filename, buf, buf_size);
int result = _g_win32_readlink_utf16_raw (filename, buf, buf_size);
gsize string_size;
if (result <= 0)
return result;
@ -532,16 +543,16 @@ _g_win32_readlink_utf16 (const gunichar2 *filename,
/* DeviceIoControl () tends to return filenames as NT Object Manager
* names , i.e. "\\??\\C:\\foo\\bar".
* Remove the leading 4-byte \??\ prefix, as glib (as well as many W32 API
* functions) is unprepared to deal with it.
* functions) is unprepared to deal with it. Unless it has no 'x:' drive
* letter part after the prefix, in which case we leave everything
* as-is, because the path could be "\??\Volume{GUID}" - stripping
* the prefix will allow it to be confused with relative links
* targeting "Volume{GUID}".
*/
if (result > ntobjm_prefix_len_bytes &&
memcmp (buf, ntobjm_prefix, ntobjm_prefix_len_bytes) == 0)
{
result -= ntobjm_prefix_len_bytes;
memmove (buf, buf + ntobjm_prefix_len_unichar2, result);
}
string_size = result / sizeof (gunichar2);
_g_win32_strip_extended_ntobjm_prefix (buf, &string_size);
return result;
return string_size * sizeof (gunichar2);
}
static gchar *