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mingw: let mingw_lstat() error early upon problems with reparse points

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When obtaining lstat information for reparse points, we need to call
`FindFirstFile()` in addition to `GetFileInformationEx()` to obtain
the type of the reparse point (symlink, mount point etc.). However,
currently there is no error handling whatsoever if `FindFirstFile()`
fails.

Call `FindFirstFile()` before modifying the `stat *buf` output parameter
and error out if the call fails.

Note: The `FindFirstFile()` return value includes all the data
that we get from `GetFileAttributesEx()`, so we could replace
`GetFileAttributesEx()` with `FindFirstFile()`. We don't do that because
`GetFileAttributesEx()` is about twice as fast for single files. I.e.
we only pay the extra cost of calling `FindFirstFile()` in the rare case
that we encounter a reparse point.

Please also note that the indentation the remaining reparse point
code changed, and hence the best way to look at this diff is with
`--color-moved -w`. That code was _not_ moved because a subsequent
commit will move it to an altogether different function, anyway.

Signed-off-by: Karsten Blees <karsten.blees@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Karsten Blees 2026-01-09 20:05:01 +00:00 committed by Junio C Hamano
parent 882e5e0528
commit 2c37842ff9
1 changed files with 14 additions and 10 deletions
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24
compat/mingw.c
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@ -920,6 +920,7 @@ static int has_valid_directory_prefix(wchar_t *wfilename)
int mingw_lstat(const char *file_name, struct stat *buf)
{
WIN32_FILE_ATTRIBUTE_DATA fdata;
WIN32_FIND_DATAW findbuf = { 0 };
wchar_t wfilename[MAX_PATH];
int wlen = xutftowcs_path(wfilename, file_name);
if (wlen < 0)
@ -934,6 +935,13 @@ int mingw_lstat(const char *file_name, struct stat *buf)
}
if (GetFileAttributesExW(wfilename, GetFileExInfoStandard, &fdata)) {
/* for reparse points, use FindFirstFile to get the reparse tag */
if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
HANDLE handle = FindFirstFileW(wfilename, &findbuf);
if (handle == INVALID_HANDLE_VALUE)
goto error;
FindClose(handle);
}
buf->st_ino = 0;
buf->st_gid = 0;
buf->st_uid = 0;
@ -946,20 +954,16 @@ int mingw_lstat(const char *file_name, struct stat *buf)
filetime_to_timespec(&(fdata.ftLastWriteTime), &(buf->st_mtim));
filetime_to_timespec(&(fdata.ftCreationTime), &(buf->st_ctim));
if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
WIN32_FIND_DATAW findbuf;
HANDLE handle = FindFirstFileW(wfilename, &findbuf);
if (handle != INVALID_HANDLE_VALUE) {
if ((findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
(findbuf.dwReserved0 == IO_REPARSE_TAG_SYMLINK)) {
buf->st_mode = S_IFLNK | S_IREAD;
if (!(findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
buf->st_mode |= S_IWRITE;
}
FindClose(handle);
if ((findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
(findbuf.dwReserved0 == IO_REPARSE_TAG_SYMLINK)) {
buf->st_mode = S_IFLNK | S_IREAD;
if (!(findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
buf->st_mode |= S_IWRITE;
}
}
return 0;
}
error:
switch (GetLastError()) {
case ERROR_ACCESS_DENIED:
case ERROR_SHARING_VIOLATION: