From 7c54988b1b3b9eb4d2f3650c1ba5ffe97673ca92 Mon Sep 17 00:00:00 2001 From: Pino Toscano Date: Thu, 10 Feb 2022 08:26:11 +0100 Subject: [PATCH] Avoid a stack buffer when not needed Allocate a PATH_MAX-sized buffer on stack only in case we are not using realpath(X, null), i.e. on platforms with older POSIX versions, macOS, or Android. This fixes the build on platforms that do not have PATH_MAX (e.g. GNU/Hurd), and it provides a minor optimization on realpath(X, null) platforms. Change-Id: Icd92a1b15ec18c5eef8113408e9610dfac774101 Reviewed-by: Thiago Macieira --- src/corelib/io/qfilesystemengine_unix.cpp | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/corelib/io/qfilesystemengine_unix.cpp b/src/corelib/io/qfilesystemengine_unix.cpp index 6e8229daec..fb66d47d38 100644 --- a/src/corelib/io/qfilesystemengine_unix.cpp +++ b/src/corelib/io/qfilesystemengine_unix.cpp @@ -686,7 +686,9 @@ QFileSystemEntry QFileSystemEngine::canonicalName(const QFileSystemEntry &entry, Q_UNUSED(data); return QFileSystemEntry(slowCanonicalized(absoluteName(entry).filePath())); #else +# if defined(Q_OS_DARWIN) || defined(Q_OS_ANDROID) || _POSIX_VERSION < 200801L char stack_result[PATH_MAX+1]; +# endif char *resolved_name = nullptr; # if defined(Q_OS_DARWIN) || defined(Q_OS_ANDROID) // On some Android and macOS versions, realpath() will return a path even if @@ -714,8 +716,10 @@ QFileSystemEntry QFileSystemEngine::canonicalName(const QFileSystemEntry &entry, data.knownFlagsMask |= QFileSystemMetaData::ExistsAttribute; data.entryFlags |= QFileSystemMetaData::ExistsAttribute; QString canonicalPath = QDir::cleanPath(QFile::decodeName(resolved_name)); +# if defined(Q_OS_DARWIN) || defined(Q_OS_ANDROID) || _POSIX_VERSION < 200801L if (resolved_name != stack_result) free(resolved_name); +# endif return QFileSystemEntry(canonicalPath); } else if (errno == ENOENT || errno == ENOTDIR) { // file doesn't exist data.knownFlagsMask |= QFileSystemMetaData::ExistsAttribute; -- 2.34.1