From 3dd74b8edbf721932508dc8fe11fa99267aa0610 Mon Sep 17 00:00:00 2001 From: Aaron Ballman Date: Mon, 20 Jun 2016 20:28:49 +0000 Subject: Fix a relatively nasty bug with fs::getPathFromOpenFD() on Windows. The GetFinalPathNameByHandle API does not behave as documented; if given a buffer that has enough space for the path but not the null terminator, the call will return the number of characters required *without* the null terminator (despite being documented otherwise) and it will not set GetLastError(). The result was that this function would return a bogus path and no error. Instead, ensure there is sufficient space for a null terminator (we already strip it off manually for compatibility with older versions of Windows). llvm-svn: 273195 --- llvm/lib/Support/Windows/Path.inc | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'llvm/lib/Support/Windows') diff --git a/llvm/lib/Support/Windows/Path.inc b/llvm/lib/Support/Windows/Path.inc index 5f588d7884e..8e5931ce6d8 100644 --- a/llvm/lib/Support/Windows/Path.inc +++ b/llvm/lib/Support/Windows/Path.inc @@ -821,11 +821,19 @@ std::error_code getPathFromOpenFD(int FD, SmallVectorImpl &ResultPath) { DWORD CharCount; do { + // FIXME: We should be using the W version of this API and converting the + // resulting path to UTF-8 to handle non-ASCII file paths. CharCount = ::GetFinalPathNameByHandleA(FileHandle, ResultPath.begin(), - ResultPath.capacity(), FILE_NAME_NORMALIZED); - if (CharCount <= ResultPath.capacity()) + ResultPath.capacity(), + FILE_NAME_NORMALIZED); + if (CharCount < ResultPath.capacity()) break; - ResultPath.reserve(CharCount); + + // Reserve sufficient space for the path as well as the null character. Even + // though the API does not document that it is required, if we reserve just + // CharCount space, the function call will not store the resulting path and + // still report success. + ResultPath.reserve(CharCount + 1); } while (true); if (CharCount == 0) @@ -833,7 +841,8 @@ std::error_code getPathFromOpenFD(int FD, SmallVectorImpl &ResultPath) { ResultPath.set_size(CharCount); - // On earlier Windows releases, the character count includes the terminating null. + // On earlier Windows releases, the character count includes the terminating + // null. if (ResultPath.back() == '\0') ResultPath.pop_back(); -- cgit v1.2.3