[llvm] ceffd69 - [Support][Windows] Fix incorrect GetFinalPathNameByHandleW() return value check in realPathFromHandle()
Aleksandr Platonov via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 26 12:12:32 PDT 2020
Author: Aleksandr Platonov
Date: 2020-08-26T22:11:44+03:00
New Revision: ceffd6993c350b57f43cec3b6371b159fc4a3149
URL: https://github.com/llvm/llvm-project/commit/ceffd6993c350b57f43cec3b6371b159fc4a3149
DIFF: https://github.com/llvm/llvm-project/commit/ceffd6993c350b57f43cec3b6371b159fc4a3149.diff
LOG: [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
Added:
Modified:
llvm/lib/Support/Windows/Path.inc
Removed:
################################################################################
diff --git a/llvm/lib/Support/Windows/Path.inc b/llvm/lib/Support/Windows/Path.inc
index 0115161636c4..399b054d36bd 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 <fcntl.h>
-#include <io.h>
#include <sys/stat.h>
#include <sys/types.h>
@@ -352,13 +351,13 @@ std::error_code is_local(const Twine &path, bool &result) {
static std::error_code realPathFromHandle(HANDLE H,
SmallVectorImpl<wchar_t> &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());
More information about the llvm-commits
mailing list