From patchwork Mon Aug 22 14:27:33 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella X-Patchwork-Id: 14842 Received: (qmail 72393 invoked by alias); 22 Aug 2016 14:27:52 -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 72350 invoked by uid 89); 22 Aug 2016 14:27:51 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 spammy=sem, asynchronous, act X-HELO: mail-ua0-f173.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references; bh=Ob3n1M+wKsOsNDJpG2SVTmKjjcBo60iKv6XZIRRaMIw=; b=jexKQz3w5B6lcpyw27ExKWTtw0jL4dBPaEqksuuoIe42fHjglNAW8SQNm2VQA1o8O8 bV6SVC3O1nh0KryUiHCoBB1DK3FYQPfBO8noZcnFO2P3lH5Y5UbmiIc6pfmwP+7cmMWT yCic1aQeacBs5CZZY3rhgxKW+dWmNG08wl83fjifYO6pQ00GxY52lLc7lVrfWqBCSFDJ NK8Gbjn+EFf/3fgY6gCjmsuWsc32kz1ZNK78swbSU/bm1hXbMMl6qA+NmZ3QMziNX/Yg mQRtbv+YH4sZhVbMFg/rekPYqvSHgHjRGN4puj835oIlcNsqV6Yieagx3PNkeZ1ET8EU ae/A== X-Gm-Message-State: AEkoousvhnMYNql/9zxy5tSHs47gV9hlbtcVvDXWym7bKOQFJyFzGum7OtZuNRA/TF/TIHJ/ X-Received: by 10.159.33.184 with SMTP id 53mr9304184uac.32.1471876064378; Mon, 22 Aug 2016 07:27:44 -0700 (PDT) From: Adhemerval Zanella To: libc-alpha@sourceware.org Subject: [PATCH 5/5] rt: Set shm_open as a non cancellation point (BZ #18243) Date: Mon, 22 Aug 2016 11:27:33 -0300 Message-Id: <1471876053-780-5-git-send-email-adhemerval.zanella@linaro.org> In-Reply-To: <1471876053-780-1-git-send-email-adhemerval.zanella@linaro.org> References: <1471876053-780-1-git-send-email-adhemerval.zanella@linaro.org> This patch changes shm_open to not act as a cancellation point. Cancellation is disable at start and reenable in function exit. It fixes BZ #18243. Tested on x86_64 and i686. [BZ #18243] * rt/Makefile (test): Add tst-shm-cancel. * rt/tst-shm-cancel.c: New file. * sysdeps/posix/shm_open.c: Disable asynchronous cancellation. --- rt/Makefile | 2 +- rt/tst-shm-cancel.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++ sysdeps/posix/shm_open.c | 7 +++ 3 files changed, 143 insertions(+), 1 deletion(-) create mode 100644 rt/tst-shm-cancel.c diff --git a/rt/Makefile b/rt/Makefile index cfa6837..7593b11 100644 --- a/rt/Makefile +++ b/rt/Makefile @@ -53,7 +53,7 @@ tests := tst-shm tst-clock tst-clock_nanosleep tst-timer tst-timer2 \ tst-timer3 tst-timer4 tst-timer5 \ tst-cpuclock1 tst-cpuclock2 \ tst-cputimer1 tst-cputimer2 tst-cputimer3 \ - tst-clock2 + tst-clock2 tst-shm-cancel extra-libs := librt extra-libs-others := $(extra-libs) diff --git a/rt/tst-shm-cancel.c b/rt/tst-shm-cancel.c new file mode 100644 index 0000000..de70c1a --- /dev/null +++ b/rt/tst-shm-cancel.c @@ -0,0 +1,135 @@ +/* Test for shm_open cancellation handling: BZ #18243. + Copyright (C) 2016 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 + . */ + +#include +#include +#include +#include +#include +#include +#include +#include + +static sem_t sem; /* Use to sync with thread start. */ +volatile int thread_ret; +static const char shm_name[] = "/glibc-shm_open-cancel"; + +static void +remove_shm (int status, void *arg) +{ + shm_unlink (shm_name); +} + +static void * +tf (void *arg) +{ + thread_ret = 0; + + pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, 0); + + if (sem_wait (&sem) != 0) + { + printf ("error: sem_wait failed: %m"); + thread_ret = 1; + return NULL; + } + + if (pthread_setcancelstate (PTHREAD_CANCEL_ENABLE, 0) != 0) + { + printf ("error: pthread_setcancelstate failed: %m"); + thread_ret = 1; + return NULL; + } + + /* Neither sem_unlink or sem_open should act on thread cancellation. */ + shm_unlink (shm_name); + on_exit (remove_shm, NULL); + + int fd = shm_open (shm_name, O_CREAT, 0600); + if (fd == -1) + { + if (errno == ENOSYS || errno == EACCES) + thread_ret = 77; + else + thread_ret = 1; + return NULL; + } + + if (pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, 0) != 0) + { + printf ("error: pthread_setcancelstate failed: %m"); + thread_ret = 1; + return NULL; + } + + if (close (fd) != 0) + { + printf ("error: pthread_setcancelstate failed: %m"); + thread_ret = 1; + } + + return NULL; +} + +static int +do_test (void) +{ + pthread_t td; + + if (sem_init (&sem, 0, 0)) + { + printf ("error: sem_init failed: %m\n"); + return 1; + } + + if (pthread_create (&td, NULL, tf, NULL) != 0) + { + printf ("error: pthread_create failed: %m\n"); + return 1; + } + + if (pthread_cancel (td) != 0) + { + printf ("error: pthread_cancel failed: %m\n"); + return 1; + } + + if (sem_post (&sem) != 0) + { + printf ("error: sem_post failed: %m\n"); + return 1; + } + + void *r; + if (pthread_join (td, &r) != 0) + { + printf ("error: pthread_join failed: %m\n"); + return 1; + } + + if (r == PTHREAD_CANCELED) + { + puts ("error: pthread_join returned PTHREAD_CANCELED"); + return 1; + } + + return thread_ret; +} + +#define TEST_FUNCTION do_test () +#include diff --git a/sysdeps/posix/shm_open.c b/sysdeps/posix/shm_open.c index f296162..0182e7b 100644 --- a/sysdeps/posix/shm_open.c +++ b/sysdeps/posix/shm_open.c @@ -40,6 +40,11 @@ shm_open (const char *name, int oflag, mode_t mode) # ifdef O_CLOEXEC oflag |= O_CLOEXEC; # endif + + /* Disable asynchronous cancellation. */ + int state; + pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state); + int fd = open (shm_name, oflag, mode); if (fd == -1 && __glibc_unlikely (errno == EISDIR)) /* It might be better to fold this error with EINVAL since @@ -70,6 +75,8 @@ shm_open (const char *name, int oflag, mode_t mode) } # endif + pthread_setcancelstate (state, NULL); + return fd; }