Win32: Fix drive root detection with \\?\-style paths

[wimlib] / src / win32_apply.c

diff --git a/src/win32_apply.c b/src/win32_apply.c
index f022e1d0bb1d2646e9edf291f51badd0a66e792c..1737fa1b49d0e9040cfe83f3efe393836240fc44 100644 (file)
--- a/src/win32_apply.c
+++ b/src/win32_apply.c
@@ -479,26 +479,6 @@ do_win32_extract_encrypted_stream(const wchar_t *path,
        return ret;
 }
 
-static bool
-path_is_root_of_drive(const wchar_t *path)
-{
-       if (*path == L'\0')
-               return false;
-
-       if (!wcsncmp(path, L"\\\\?\\", 4))
-               path += 4;
-
-       if (*path != L'/' && *path != L'\\') {
-               if (*(path + 1) == L':')
-                       path += 2;
-               else
-                       return false;
-       }
-       while (*path == L'/' || *path == L'\\')
-               path++;
-       return (*path == L'\0');
-}
-
 static inline DWORD
 win32_mask_attributes(DWORD i_attributes)
 {
@@ -602,7 +582,7 @@ win32_begin_extract_unnamed_stream(const struct wim_inode *inode,
         * to CreateFileW() will merely open the directory that was already
         * created rather than creating a new file. */
        if (inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY) {
-               if (!path_is_root_of_drive(path)) {
+               if (!win32_path_is_root_of_drive(path)) {
                        if (!CreateDirectoryW(path, NULL)) {
                                err = GetLastError();
                                if (err != ERROR_ALREADY_EXISTS) {
@@ -655,7 +635,7 @@ win32_begin_extract_unnamed_stream(const struct wim_inode *inode,
         * directory, so treat that as a special case and do not set attributes.
         * */
        if (*creationDisposition_ret == OPEN_EXISTING &&
-           !path_is_root_of_drive(path))
+           !win32_path_is_root_of_drive(path))
        {
                if (!SetFileAttributesW(path,
                                        win32_mask_attributes(inode->i_attributes)))
@@ -813,12 +793,12 @@ win32_extract_stream(const struct wim_dentry *dentry,
 
        if (stream_name_utf16) {
                /* Named stream.  Create a buffer that contains the UTF-16LE
-                * string [./]path:stream_name_utf16.  This is needed to
+                * string [.\]path:stream_name_utf16.  This is needed to
                 * create and open the stream using CreateFileW().  I'm not
                 * aware of any other APIs to do this.  Note: the '$DATA' suffix
-                * seems to be unneeded.  Additional note: a "./" prefix needs
-                * to be added when the path is not absolute to avoid ambiguity
-                * with drive letters. */
+                * seems to be unneeded.  Additional note: a ".\" prefix needs
+                * to be added when the path is a 1-character long relative path
+                * to avoid ambiguity with drive letters. */
                size_t stream_path_nchars;
                size_t path_nchars;
                size_t stream_name_nchars;
@@ -827,12 +807,10 @@ win32_extract_stream(const struct wim_dentry *dentry,
                path_nchars = wcslen(path);
                stream_name_nchars = wcslen(stream_name_utf16);
                stream_path_nchars = path_nchars + 1 + stream_name_nchars;
-               if (path[0] != cpu_to_le16(L'\0') &&
-                   path[0] != cpu_to_le16(L'/') &&
-                   path[0] != cpu_to_le16(L'\\') &&
-                   path[1] != cpu_to_le16(L':'))
-               {
-                       prefix = L"./";
+               if (path_nchars == 1 && !is_any_path_separator(path[0])) {
+                       static const wchar_t _prefix[] =
+                               {L'.', OS_PREFERRED_PATH_SEPARATOR, L'\0'};
+                       prefix = _prefix;
                        stream_path_nchars += 2;
                } else {
                        prefix = L"";
@@ -871,7 +849,7 @@ try_open_again:
        if (h == INVALID_HANDLE_VALUE) {
                err = GetLastError();
                if (err == ERROR_ACCESS_DENIED &&
-                   path_is_root_of_drive(stream_path))
+                   win32_path_is_root_of_drive(stream_path))
                {
                        ret = 0;
                        goto out;
@@ -1285,7 +1263,7 @@ win32_do_apply_dentry_timestamps(const wchar_t *path,
        /* Windows doesn't let you change the timestamps of the root directory
         * (at least on FAT, which is dumb but expected since FAT doesn't store
         * any metadata about the root directory...) */
-       if (path_is_root_of_drive(path))
+       if (win32_path_is_root_of_drive(path))
                return 0;
 
        DEBUG("Opening \"%ls\" to set timestamps", path);