From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from elaine.keithp.com (home.keithp.com [63.227.221.253]) by sourceware.org (Postfix) with ESMTPS id E8F01394DAD7; Mon, 7 Dec 2020 18:39:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E8F01394DAD7 Received: from localhost (localhost [127.0.0.1]) by elaine.keithp.com (Postfix) with ESMTP id 077803F2DFE6; Mon, 7 Dec 2020 10:39:36 -0800 (PST) X-Virus-Scanned: Debian amavisd-new at keithp.com Received: from elaine.keithp.com ([127.0.0.1]) by localhost (elaine.keithp.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Hetg-DQkE4cL; Mon, 7 Dec 2020 10:39:31 -0800 (PST) Received: from keithp.com (koto.keithp.com [10.0.0.2]) by elaine.keithp.com (Postfix) with ESMTPSA id 9D1D53F2E1EB; Mon, 7 Dec 2020 10:39:30 -0800 (PST) Received: by keithp.com (Postfix, from userid 1000) id 68F711582185; Mon, 7 Dec 2020 10:39:30 -0800 (PST) From: Keith Packard To: libstdc++@gcc.gnu.org Cc: gcc@gcc.gnu.org, Keith Packard Subject: [PATCH 1/2] libstdc++: Add --enable-pure-stdio-libstdcxx option Date: Mon, 7 Dec 2020 10:39:26 -0800 Message-Id: <20201207183927.3275768-2-keithp@keithp.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201207183927.3275768-1-keithp@keithp.com> References: <20201207183927.3275768-1-keithp@keithp.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-10.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libstdc++@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++ mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Dec 2020 18:39:41 -0000 This option directs the library to only use simple stdio APIs instead of using fileno to get the file descriptor for use with POSIX APIs. Signed-off-by: Keith Packard --- libstdc++-v3/ChangeLog | 13 ++++++ libstdc++-v3/acinclude.m4 | 13 ++++++ libstdc++-v3/config/io/basic_file_stdio.cc | 46 +++++++++++++++++++--- libstdc++-v3/configure.ac | 1 + 4 files changed, 68 insertions(+), 5 deletions(-) diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index d3ee18ed7d1..7f6b0697534 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1147,6 +1147,19 @@ * include/bits/uniform_int_dist.h (uniform_int_distribution::_S_nd): Use qualified-id to refer to static member functions. +2020-11-04 Keith Packard + + * acinclude.m4: Add GLIBCXX_ENABLE_PURE_STDIO for + --enable-libstdcxx-pure-stdio + * configure.ac: Use GLIBCXX_ENABLE_PURE_STDIO for + --enable-libstdcxx-pure-stdio + * configure: regenerate + * config.h.in: regenerate + * config/io/basic_file_stdio.cc: Add support for + _GLIBCXX_USE_PURE_STDIO. This makes libstdc++ use only defined + stdio entry points for all I/O operations, without direct calls to + underlying POSIX functions. + 2020-11-03 Jonathan Wakely * include/std/syncstream: Include diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index fcd9ea3d23a..863695e68e7 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -2889,6 +2889,19 @@ AC_DEFUN([GLIBCXX_ENABLE_CSTDIO], [ ]) +dnl +dnl Check whether to use 'pure' stdio (no POSIX calls at all) +dnl +dnl Default is 'no' +AC_DEFUN([GLIBCXX_ENABLE_PURE_STDIO], [ + GLIBCXX_ENABLE(libstdcxx-pure-stdio,$1,,[use only stdio APIs]) + if test $enable_libstdcxx_pure_stdio = yes; then + AC_DEFINE(_GLIBCXX_USE_PURE_STDIO, 1, + [Define to restrict code to stdio APIs.]) + fi +]) + + dnl dnl Check for "unusual" flags to pass to the compiler while building. dnl diff --git a/libstdc++-v3/config/io/basic_file_stdio.cc b/libstdc++-v3/config/io/basic_file_stdio.cc index ba830fb9e97..d31da8497f4 100644 --- a/libstdc++-v3/config/io/basic_file_stdio.cc +++ b/libstdc++-v3/config/io/basic_file_stdio.cc @@ -111,13 +111,21 @@ namespace // Wrapper handling partial write. static std::streamsize +#ifdef _GLIBCXX_USE_PURE_STDIO + xwrite(FILE *__file, const char* __s, std::streamsize __n) +#else xwrite(int __fd, const char* __s, std::streamsize __n) +#endif { std::streamsize __nleft = __n; for (;;) { +#ifdef _GLIBCXX_USE_PURE_STDIO + const std::streamsize __ret = fwrite(__file, 1, __nleft, __file); +#else const std::streamsize __ret = write(__fd, __s, __nleft); +#endif if (__ret == -1L && errno == EINTR) continue; if (__ret == -1L) @@ -133,7 +141,7 @@ namespace return __n - __nleft; } -#ifdef _GLIBCXX_HAVE_WRITEV +#if defined(_GLIBCXX_HAVE_WRITEV) && !defined(_GLIBCXX_USE_PURE_STDIO) // Wrapper handling partial writev. static std::streamsize xwritev(int __fd, const char* __s1, std::streamsize __n1, @@ -286,9 +294,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION __basic_file::is_open() const throw () { return _M_cfile != 0; } +#ifndef _GLIBCCXX_USE_PURE_STDIO int __basic_file::fd() throw () { return fileno(_M_cfile); } +#endif __c_file* __basic_file::file() throw () @@ -315,28 +325,46 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { streamsize __ret; do +#ifdef _GLIBCXX_USE_PURE_STDIO + __ret = fread(__s, 1, __n, this->file()); +#else __ret = read(this->fd(), __s, __n); +#endif while (__ret == -1L && errno == EINTR); return __ret; } streamsize __basic_file::xsputn(const char* __s, streamsize __n) - { return xwrite(this->fd(), __s, __n); } + { +#ifdef _GLIBCXX_USE_PURE_STDIO + return xwrite(this->file(), __s, __n); +#else + return xwrite(this->fd(), __s, __n); +#endif + } streamsize __basic_file::xsputn_2(const char* __s1, streamsize __n1, const char* __s2, streamsize __n2) { streamsize __ret = 0; -#ifdef _GLIBCXX_HAVE_WRITEV +#if defined(_GLIBCXX_HAVE_WRITEV) && !defined(_GLIBCXX_USE_PURE_STDIO) __ret = xwritev(this->fd(), __s1, __n1, __s2, __n2); #else if (__n1) +#ifdef _GLIBCXX_USE_PURE_STDIO + __ret = xwrite(this->file(), __s1, __n1); +#else __ret = xwrite(this->fd(), __s1, __n1); +#endif if (__ret == __n1) +#ifdef _GLIBCXX_USE_PURE_STDIO + __ret += xwrite(this->file(), __s2, __n2); +#else __ret += xwrite(this->fd(), __s2, __n2); +#endif #endif return __ret; } @@ -350,7 +378,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION if (__off > numeric_limits::max() || __off < numeric_limits::min()) return -1L; +#ifdef _GLIBCXX_USE_PURE_STDIO + return fseek(this->file(), __off, __way); +#else return lseek(this->fd(), __off, __way); +#endif #endif } @@ -361,7 +393,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION streamsize __basic_file::showmanyc() { -#ifndef _GLIBCXX_NO_IOCTL +#if !defined(_GLIBCXX_NO_IOCTL) && !defined(_GLIBCXX_USE_PURE_STDIO) #ifdef FIONREAD // Pipes and sockets. int __num = 0; @@ -371,7 +403,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION #endif #endif -#ifdef _GLIBCXX_HAVE_POLL +#if defined(_GLIBCXX_HAVE_POLL) && !defined(_GLIBCXX_USE_PURE_STDIO) // Cheap test. struct pollfd __pfd[1]; __pfd[0].fd = this->fd(); @@ -395,8 +427,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION struct stat __buffer; const int __err = fstat(this->fd(), &__buffer); if (!__err && _GLIBCXX_ISREG(__buffer.st_mode)) +#ifdef _GLIBCXX_USE_PURE_STDIO + return __buffer.st_size - fseek(this->file(), 0, ios_base::cur); +#else return __buffer.st_size - lseek(this->fd(), 0, ios_base::cur); #endif +#endif #endif return 0; } diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac index cbfdf4c6bad..733154d070b 100644 --- a/libstdc++-v3/configure.ac +++ b/libstdc++-v3/configure.ac @@ -179,6 +179,7 @@ GLIBCXX_ENABLE_EXTERN_TEMPLATE([yes]) GLIBCXX_ENABLE_PYTHON GLIBCXX_ENABLE_WERROR([no]) GLIBCXX_ENABLE_VTABLE_VERIFY([no]) +GLIBCXX_ENABLE_PURE_STDIO # Checks for operating systems support that doesn't require linking. GLIBCXX_CHECK_STDIO_PROTO -- 2.29.2