[PATCH v2 02/18] mingw: implement `stat()` with symlink support

["Karsten Blees via GitGitGadget" <gitgitgadget@gmail.com>]

From: Karsten Blees <karsten.blees@gmail.com>

With respect to symlinks, the current `mingw_stat()` implementation is
almost identical to `mingw_lstat()`: except for the file type (`st_mode
& S_IFMT`), it returns information about the link rather than the target.

Implement `mingw_stat()` by opening the file handle requesting minimal
permissions, and then calling `GetFileInformationByHandle()` on it. This
way, all links are resolved by the Windows file system layer.

Signed-off-by: Karsten Blees <karsten.blees@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index ae6826948e..13970ae729 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1027,9 +1027,26 @@ int mingw_lstat(const char *file_name, struct stat *buf)
 {
 	return do_lstat(0, file_name, buf);
 }
+
 int mingw_stat(const char *file_name, struct stat *buf)
 {
-	return do_lstat(1, file_name, buf);
+	wchar_t wfile_name[MAX_PATH];
+	HANDLE hnd;
+	int result;
+
+	/* open the file and let Windows resolve the links */
+	if (xutftowcs_path(wfile_name, file_name) < 0)
+		return -1;
+	hnd = CreateFileW(wfile_name, 0,
+			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+			OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+	if (hnd == INVALID_HANDLE_VALUE) {
+		errno = err_win_to_posix(GetLastError());
+		return -1;
+	}
+	result = get_file_info_by_handle(hnd, buf);
+	CloseHandle(hnd);
+	return result;
 }
 
 int mingw_fstat(int fd, struct stat *buf)
-- 
gitgitgadget