From 4a52cf2eb9d6864ad85674ab56838e0d9ce27926 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 25 Jun 2021 18:31:23 +0100 Subject: [PATCH] libstdc++: Avoid intercepting exception in ostream::write Currently if ostream::write fails and sets badbit and that causes an exception, we will catch the exception, set badbit again, and rethrow the exception. This change delays setting badbit until after the try-catch block, so that if it causes an exception we don't need to catch and rethrow it. This removes the last remaining use of _M_write, so it can be made private (or removed entirely for versioned namespace builds, where ABI compatibility is not required). All other uses of _M_write were replaced by calls to __ostream_insert, so make _M_write use that too. libstdc++-v3/ChangeLog: * include/bits/ostream.tcc (basic_ostream::write): Call sputn directly instead of using _M_write. Do setstate(__err) all outside the try-catch block. * include/std/ostream (basic_ostream::_M_write): Declare private. Use __ostream_insert. Do not define for the versioned namespace. --- libstdc++-v3/include/bits/ostream.tcc | 8 +++++++- libstdc++-v3/include/std/ostream | 20 +++++++------------- 2 files changed, 14 insertions(+), 14 deletions(-) diff --git a/libstdc++-v3/include/bits/ostream.tcc b/libstdc++-v3/include/bits/ostream.tcc index d3220e8..06b2217 100644 --- a/libstdc++-v3/include/bits/ostream.tcc +++ b/libstdc++-v3/include/bits/ostream.tcc @@ -192,8 +192,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION sentry __cerb(*this); if (__cerb) { + ios_base::iostate __err = ios_base::goodbit; __try - { _M_write(__s, __n); } + { + if (this->rdbuf()->sputn(__s, __n) != __n) + __err = ios_base::badbit; + } __catch(__cxxabiv1::__forced_unwind&) { this->_M_setstate(ios_base::badbit); @@ -201,6 +205,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION } __catch(...) { this->_M_setstate(ios_base::badbit); } + if (__err) + this->setstate(ios_base::badbit); } return *this; } diff --git a/libstdc++-v3/include/std/ostream b/libstdc++-v3/include/std/ostream index 9816973..ddb33fe 100644 --- a/libstdc++-v3/include/std/ostream +++ b/libstdc++-v3/include/std/ostream @@ -309,19 +309,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION put(char_type __c); /** - * @brief Core write functionality, without sentry. - * @param __s The array to insert. - * @param __n Maximum number of characters to insert. - */ - void - _M_write(const char_type* __s, streamsize __n) - { - const streamsize __put = this->rdbuf()->sputn(__s, __n); - if (__put != __n) - this->setstate(ios_base::badbit); - } - - /** * @brief Character string insertion. * @param __s The array to insert. * @param __n Maximum number of characters to insert. @@ -419,6 +406,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template __ostream_type& _M_insert(_ValueT __v); + + private: +#if !_GLIBCXX_INLINE_VERSION + void + _M_write(const char_type* __s, streamsize __n) + { std::__ostream_insert(*this, __s, __n); } +#endif }; /** -- 2.7.4