From patchwork Thu Feb 13 14:00:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Schwab X-Patchwork-Id: 38028 Received: (qmail 104650 invoked by alias); 13 Feb 2020 14:01:05 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 103698 invoked by uid 89); 13 Feb 2020 14:00:50 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-15.3 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, SPF_PASS autolearn=ham version=3.3.1 spammy= X-HELO: mx2.suse.de From: Andreas Schwab To: libc-alpha@sourceware.org Subject: [PATCH] Always do locking when accessing streams (bug 15142, bug 14697) X-Yow: .. hubub, hubub, HUBUB, hubub, hubub, hubub, HUBUB, hubub, hubub, hubub. Date: Thu, 13 Feb 2020 15:00:43 +0100 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Now that abort no longer calls fflush there is no reason to avoid locking the stdio streams anywhere. This fixes a conformance issue and potential heap corruption during exit. The test nptl/tst-stdio1 is removed as that was expecting the problematic behaviour. --- libio/genops.c | 43 +++++++++--------------------------- libio/libioP.h | 1 - nptl/Makefile | 2 +- nptl/tst-stdio1.c | 56 ----------------------------------------------- 4 files changed, 11 insertions(+), 91 deletions(-) delete mode 100644 nptl/tst-stdio1.c diff --git a/libio/genops.c b/libio/genops.c index 28419cc963..0fbdbeca7c 100644 --- a/libio/genops.c +++ b/libio/genops.c @@ -682,7 +682,7 @@ _IO_adjust_column (unsigned start, const char *line, int count) libc_hidden_def (_IO_adjust_column) int -_IO_flush_all_lockp (int do_lock) +_IO_flush_all (void) { int result = 0; FILE *fp; @@ -695,8 +695,7 @@ _IO_flush_all_lockp (int do_lock) for (fp = (FILE *) _IO_list_all; fp != NULL; fp = fp->_chain) { run_fp = fp; - if (do_lock) - _IO_flockfile (fp); + _IO_flockfile (fp); if (((fp->_mode <= 0 && fp->_IO_write_ptr > fp->_IO_write_base) || (_IO_vtable_offset (fp) == 0 @@ -706,8 +705,7 @@ _IO_flush_all_lockp (int do_lock) && _IO_OVERFLOW (fp, EOF) == EOF) result = EOF; - if (do_lock) - _IO_funlockfile (fp); + _IO_funlockfile (fp); run_fp = NULL; } @@ -718,14 +716,6 @@ _IO_flush_all_lockp (int do_lock) return result; } - - -int -_IO_flush_all (void) -{ - /* We want locking. */ - return _IO_flush_all_lockp (1); -} libc_hidden_def (_IO_flush_all) void @@ -791,6 +781,9 @@ _IO_unbuffer_all (void) { int legacy = 0; + run_fp = fp; + _IO_flockfile (fp); + #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) if (__glibc_unlikely (_IO_vtable_offset (fp) != 0)) legacy = 1; @@ -800,18 +793,6 @@ _IO_unbuffer_all (void) /* Iff stream is un-orientated, it wasn't used. */ && (legacy || fp->_mode != 0)) { -#ifdef _IO_MTSAFE_IO - int cnt; -#define MAXTRIES 2 - for (cnt = 0; cnt < MAXTRIES; ++cnt) - if (fp->_lock == NULL || _IO_lock_trylock (*fp->_lock) == 0) - break; - else - /* Give the other thread time to finish up its use of the - stream. */ - __sched_yield (); -#endif - if (! legacy && ! dealloc_buffers && !(fp->_flags & _IO_USER_BUF)) { fp->_flags |= _IO_USER_BUF; @@ -825,17 +806,15 @@ _IO_unbuffer_all (void) if (! legacy && fp->_mode > 0) _IO_wsetb (fp, NULL, NULL, 0); - -#ifdef _IO_MTSAFE_IO - if (cnt < MAXTRIES && fp->_lock != NULL) - _IO_lock_unlock (*fp->_lock); -#endif } /* Make sure that never again the wide char functions can be used. */ if (! legacy) fp->_mode = -1; + + _IO_funlockfile (fp); + run_fp = NULL; } #ifdef _IO_MTSAFE_IO @@ -861,9 +840,7 @@ libc_freeres_fn (buffer_free) int _IO_cleanup (void) { - /* We do *not* want locking. Some threads might use streams but - that is their problem, we flush them underneath them. */ - int result = _IO_flush_all_lockp (0); + int result = _IO_flush_all (); /* We currently don't have a reliable mechanism for making sure that C++ static destructors are executed in the correct order. diff --git a/libio/libioP.h b/libio/libioP.h index 7e446e3030..55697b27cb 100644 --- a/libio/libioP.h +++ b/libio/libioP.h @@ -487,7 +487,6 @@ extern int _IO_new_do_write (FILE *, const char *, size_t); extern int _IO_old_do_write (FILE *, const char *, size_t); extern int _IO_wdo_write (FILE *, const wchar_t *, size_t); libc_hidden_proto (_IO_wdo_write) -extern int _IO_flush_all_lockp (int); extern int _IO_flush_all (void); libc_hidden_proto (_IO_flush_all) extern int _IO_cleanup (void); diff --git a/nptl/Makefile b/nptl/Makefile index 6f210d60e3..d248f1ddb6 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -277,7 +277,7 @@ tests = tst-attr2 tst-attr3 tst-default-attr \ tst-signal6 \ tst-exec1 tst-exec2 tst-exec3 tst-exec4 tst-exec5 \ tst-exit1 tst-exit2 tst-exit3 \ - tst-stdio1 tst-stdio2 \ + tst-stdio2 \ tst-stack1 tst-stack2 tst-stack3 tst-stack4 \ tst-pthread-attr-affinity tst-pthread-mutexattr \ tst-unload \ diff --git a/nptl/tst-stdio1.c b/nptl/tst-stdio1.c deleted file mode 100644 index 66696a92ee..0000000000 --- a/nptl/tst-stdio1.c +++ /dev/null @@ -1,56 +0,0 @@ -/* Copyright (C) 2002-2020 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Ulrich Drepper , 2002. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include -#include -#include - -static int do_test (void); - -#define TEST_FUNCTION do_test () -#include "../test-skeleton.c" - -static void *tf (void *a) -{ - flockfile (stdout); - /* This call should never return. */ - return a; -} - - -int -do_test (void) -{ - pthread_t th; - - flockfile (stdout); - - if (pthread_create (&th, NULL, tf, NULL) != 0) - { - write_message ("create failed\n"); - _exit (1); - } - - delayed_exit (1); - xpthread_join (th); - - puts ("join returned"); - - return 1; -}