diff options
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | libio/memstream.c | 3 | ||||
| -rw-r--r-- | libio/wmemstream.c | 3 | ||||
| -rw-r--r-- | nptl/Makefile | 2 | ||||
| -rw-r--r-- | nptl/tst-memstream.c | 101 |
5 files changed, 115 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog index e2605cb9c3..96c76f72ec 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2017-07-14 Szabolcs Nagy <szabolcs.nagy@arm.com> + Florian Weimer <fweimer@redhat.com> + + * libio/memstream.c (__open_memstream): Set _IO_FLAGS2_NEED_LOCK. + * libio/wmemstream.c (open_wmemstream): Likewise. + * nptl/tst-memstream.c: New. + 2017-07-12 Jiong Wang <jiong.wang@arm.com> * sysdeps/arm/dl-machine.h (elf_machine_load_address): Also strip bit 0 diff --git a/libio/memstream.c b/libio/memstream.c index f83d4a5213..e391efd48a 100644 --- a/libio/memstream.c +++ b/libio/memstream.c @@ -96,6 +96,9 @@ __open_memstream (char **bufloc, _IO_size_t *sizeloc) new_f->fp.bufloc = bufloc; new_f->fp.sizeloc = sizeloc; + /* Disable single thread optimization. BZ 21735. */ + new_f->fp._sf._sbf._f._flags2 |= _IO_FLAGS2_NEED_LOCK; + return (_IO_FILE *) &new_f->fp._sf._sbf; } libc_hidden_def (__open_memstream) diff --git a/libio/wmemstream.c b/libio/wmemstream.c index 5bc77f52ee..103a760bf5 100644 --- a/libio/wmemstream.c +++ b/libio/wmemstream.c @@ -98,6 +98,9 @@ open_wmemstream (wchar_t **bufloc, _IO_size_t *sizeloc) new_f->fp.bufloc = bufloc; new_f->fp.sizeloc = sizeloc; + /* Disable single thread optimization. BZ 21735. */ + new_f->fp._sf._sbf._f._flags2 |= _IO_FLAGS2_NEED_LOCK; + return (_IO_FILE *) &new_f->fp._sf._sbf; } diff --git a/nptl/Makefile b/nptl/Makefile index 853da72e74..dd01994d3e 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -302,7 +302,7 @@ tests = tst-attr1 tst-attr2 tst-attr3 tst-default-attr \ c89 gnu89 c99 gnu99 c11 gnu11) \ tst-bad-schedattr \ tst-thread_local1 tst-mutex-errorcheck tst-robust10 \ - tst-robust-fork tst-create-detached + tst-robust-fork tst-create-detached tst-memstream tests-internal := tst-typesizes tst-rwlock19 tst-sem11 tst-sem12 tst-sem13 \ tst-barrier5 tst-signal7 tst-mutex8 tst-mutex8-static \ diff --git a/nptl/tst-memstream.c b/nptl/tst-memstream.c new file mode 100644 index 0000000000..c88f708a50 --- /dev/null +++ b/nptl/tst-memstream.c @@ -0,0 +1,101 @@ +/* Test for open_memstream locking. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 + <http://www.gnu.org/licenses/>. */ + +/* This test checks if concurrent writes to a FILE created with + open_memstream are correctly interleaved without loss or corruption + of data. Large number of concurrent fputc operations are used + and in the end the bytes written to the memstream buffer are + counted to see if they all got recorded. + + This is a regression test to see if the single threaded stdio + optimization broke multi-threaded open_memstream usage. */ + +#include <pthread.h> +#include <stdio.h> +#include <support/check.h> +#include <support/xthread.h> + +enum +{ + thread_count = 2, + byte_count = 1000000, +}; + +struct closure +{ + FILE *fp; + char b; +}; + +static void * +thread_func (void *closure) +{ + struct closure *args = closure; + + for (int i = 0; i < byte_count; ++i) + fputc (args->b, args->fp); + + return NULL; +} + +int +do_test (void) +{ + char *buffer = NULL; + size_t buffer_length = 0; + FILE *fp = open_memstream (&buffer, &buffer_length); + if (fp == NULL) + FAIL_RET ("open_memstream: %m"); + + pthread_t threads[thread_count]; + struct closure args[thread_count]; + + for (int i = 0; i < thread_count; ++i) + { + args[i].fp = fp; + args[i].b = 'A' + i; + threads[i] = xpthread_create (NULL, thread_func, args + i); + } + + for (int i = 0; i < thread_count; ++i) + xpthread_join (threads[i]); + + fclose (fp); + + if (buffer_length != thread_count * byte_count) + FAIL_RET ("unexpected number of written bytes: %zu (should be %d)", + buffer_length, thread_count * byte_count); + + /* Verify that each thread written its unique character byte_count times. */ + size_t counts[thread_count] = { 0, }; + for (size_t i = 0; i < buffer_length; ++i) + { + if (buffer[i] < 'A' || buffer[i] >= 'A' + thread_count) + FAIL_RET ("written byte at %zu out of range: %d", i, buffer[i] & 0xFF); + ++counts[buffer[i] - 'A']; + } + for (int i = 0; i < thread_count; ++i) + if (counts[i] != byte_count) + FAIL_RET ("incorrect write count for thread %d: %zu (should be %d)", i, + counts[i], byte_count); + + return 0; +} + +#define TIMEOUT 100 +#include <support/test-driver.c> |