From f684355e0292b8e24a0870ecfda126fb15c9eb93 Mon Sep 17 00:00:00 2001 From: Aleksandr Platonov Date: Wed, 26 Aug 2020 22:10:35 +0300 Subject: [Support][Windows] Fix incorrect GetFinalPathNameByHandleW() return value check in realPathFromHandle() `GetFinalPathNameByHandleW(,,N,)` returns: - `< N` on success (this value does not include the size of the terminating null character) - `>= N` if buffer is too small (this value includes the size of the terminating null character) So, when `N == Buffer.capacity() - 1`, we need to resize buffer if return value is > `Buffer.capacity() - 2`. Also, we can set `N` to `Buffer.capacity()`. Thus, without this patch `realPathFromHandle()` returns unfilled buffer when length of the final path of the file is equal to `Buffer.capacity()` or `Buffer.capacity() - 1`. Reviewed By: andrewng, amccarth Differential Revision: https://reviews.llvm.org/D86564 (cherry picked from commit ceffd6993c350b57f43cec3b6371b159fc4a3149) --- llvm/lib/Support/Windows/Path.inc | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/llvm/lib/Support/Windows/Path.inc b/llvm/lib/Support/Windows/Path.inc index e352beb77616..365ab01c0a16 100644 --- a/llvm/lib/Support/Windows/Path.inc +++ b/llvm/lib/Support/Windows/Path.inc @@ -19,7 +19,6 @@ #include "llvm/Support/ConvertUTF.h" #include "llvm/Support/WindowsError.h" #include -#include #include #include @@ -352,13 +351,13 @@ std::error_code is_local(const Twine &path, bool &result) { static std::error_code realPathFromHandle(HANDLE H, SmallVectorImpl &Buffer) { DWORD CountChars = ::GetFinalPathNameByHandleW( - H, Buffer.begin(), Buffer.capacity() - 1, FILE_NAME_NORMALIZED); - if (CountChars > Buffer.capacity()) { + H, Buffer.begin(), Buffer.capacity(), FILE_NAME_NORMALIZED); + if (CountChars && CountChars >= Buffer.capacity()) { // The buffer wasn't big enough, try again. In this case the return value // *does* indicate the size of the null terminator. Buffer.reserve(CountChars); CountChars = ::GetFinalPathNameByHandleW( - H, Buffer.data(), Buffer.capacity() - 1, FILE_NAME_NORMALIZED); + H, Buffer.begin(), Buffer.capacity(), FILE_NAME_NORMALIZED); } if (CountChars == 0) return mapWindowsError(GetLastError()); -- cgit v1.2.3-65-gdbad