2003-04-01 03:46:29 +00:00
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/*
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2015-01-03 18:38:46 +00:00
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* Copyright (c) 2014 The FreeBSD Foundation.
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2005-04-02 01:20:00 +00:00
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* Copyright (C) 2005 David Xu <davidxu@freebsd.org>.
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* Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>.
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* Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
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2003-04-01 03:46:29 +00:00
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* All rights reserved.
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*
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2015-01-03 18:38:46 +00:00
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* Portions of this software were developed by Konstantin Belousov
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* under sponsorship from the FreeBSD Foundation.
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*
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2003-04-01 03:46:29 +00:00
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice(s), this list of conditions and the following disclaimer as
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* the first lines of this file unmodified other than the possible
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* addition of one or more copyright notices.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice(s), this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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2017-11-20 19:49:47 +00:00
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/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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2003-04-01 03:46:29 +00:00
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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2007-01-12 07:26:21 +00:00
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* 3. Neither the name of the author nor the names of any co-contributors
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2003-04-01 03:46:29 +00:00
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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2015-01-03 18:38:46 +00:00
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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2006-04-04 02:57:49 +00:00
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#include "namespace.h"
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2005-04-02 01:20:00 +00:00
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#include <sys/types.h>
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2003-04-01 03:46:29 +00:00
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#include <sys/mman.h>
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#include <sys/param.h>
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#include <sys/select.h>
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2005-04-02 01:20:00 +00:00
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#include <sys/signalvar.h>
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2004-09-16 13:55:46 +00:00
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#include <sys/socket.h>
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2005-04-02 01:20:00 +00:00
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#include <sys/stat.h>
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2003-04-01 03:46:29 +00:00
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#include <sys/time.h>
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#include <sys/uio.h>
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#include <sys/wait.h>
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#include <aio.h>
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#include <dirent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <poll.h>
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#include <signal.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <termios.h>
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#include <unistd.h>
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2005-04-02 01:20:00 +00:00
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#include <pthread.h>
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2006-04-04 02:57:49 +00:00
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#include "un-namespace.h"
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2003-04-01 03:46:29 +00:00
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2015-01-03 18:38:46 +00:00
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#include "libc_private.h"
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2003-04-01 03:46:29 +00:00
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#include "thr_private.h"
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2015-01-03 18:38:46 +00:00
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static int
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__thr_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
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2004-09-16 13:55:46 +00:00
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{
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2005-04-02 01:20:00 +00:00
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struct pthread *curthread;
|
2004-09-16 13:55:46 +00:00
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int ret;
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|
2005-04-02 01:20:00 +00:00
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curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
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|
_thr_cancel_enter(curthread);
|
2004-09-16 13:55:46 +00:00
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|
ret = __sys_accept(s, addr, addrlen);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
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_thr_cancel_leave(curthread, ret == -1);
|
2005-04-02 01:20:00 +00:00
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return (ret);
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2004-09-16 13:55:46 +00:00
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}
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2013-05-01 20:10:21 +00:00
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/*
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* Cancellation behavior:
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* If thread is canceled, no socket is created.
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*/
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2015-01-03 18:38:46 +00:00
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static int
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__thr_accept4(int s, struct sockaddr *addr, socklen_t *addrlen, int flags)
|
2013-05-01 20:10:21 +00:00
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|
{
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struct pthread *curthread;
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int ret;
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curthread = _get_curthread();
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_thr_cancel_enter(curthread);
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ret = __sys_accept4(s, addr, addrlen, flags);
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_thr_cancel_leave(curthread, ret == -1);
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return (ret);
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}
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2015-01-03 18:38:46 +00:00
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static int
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__thr_aio_suspend(const struct aiocb * const iocbs[], int niocb, const struct
|
2003-04-01 03:46:29 +00:00
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timespec *timeout)
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{
|
2015-01-03 18:38:46 +00:00
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struct pthread *curthread;
|
2005-04-02 01:20:00 +00:00
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int ret;
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2003-04-01 03:46:29 +00:00
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2015-01-03 18:38:46 +00:00
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curthread = _get_curthread();
|
2006-11-24 09:57:38 +00:00
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_thr_cancel_enter(curthread);
|
2003-04-01 03:46:29 +00:00
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ret = __sys_aio_suspend(iocbs, niocb, timeout);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
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|
_thr_cancel_leave(curthread, 1);
|
2003-04-01 03:46:29 +00:00
|
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|
2005-04-02 01:20:00 +00:00
|
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return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
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/*
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* Cancellation behavior:
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* According to manual of close(), the file descriptor is always deleted.
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* Here, thread is only canceled after the system call, so the file
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* descriptor is always deleted despite whether the thread is canceled
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* or not.
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*/
|
2015-01-03 18:38:46 +00:00
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static int
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__thr_close(int fd)
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2003-04-01 03:46:29 +00:00
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{
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2015-01-03 18:38:46 +00:00
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struct pthread *curthread;
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int ret;
|
2003-04-01 03:46:29 +00:00
|
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|
|
2015-01-03 18:38:46 +00:00
|
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|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
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_thr_cancel_enter2(curthread, 0);
|
2003-04-01 03:46:29 +00:00
|
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|
ret = __sys_close(fd);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, 1);
|
2003-04-01 03:46:29 +00:00
|
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|
2005-04-02 01:20:00 +00:00
|
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|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
2004-09-16 13:55:46 +00:00
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* If the thread is canceled, connection is not made.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_connect(int fd, const struct sockaddr *name, socklen_t namelen)
|
2004-09-16 13:55:46 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2004-09-16 13:55:46 +00:00
|
|
|
int ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2005-04-02 01:20:00 +00:00
|
|
|
ret = __sys_connect(fd, name, namelen);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2005-04-02 01:20:00 +00:00
|
|
|
|
|
|
|
return (ret);
|
2004-09-16 13:55:46 +00:00
|
|
|
}
|
2005-04-02 01:20:00 +00:00
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* According to specification, only F_SETLKW is a cancellation point.
|
|
|
|
* Thread is only canceled at start, or canceled if the system call
|
|
|
|
* is failure, this means the function does not generate side effect
|
|
|
|
* if it is canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_fcntl(int fd, int cmd, ...)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
2003-04-01 03:46:29 +00:00
|
|
|
va_list ap;
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
2003-04-01 03:46:29 +00:00
|
|
|
va_start(ap, cmd);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
if (cmd == F_OSETLKW || cmd == F_SETLKW) {
|
|
|
|
_thr_cancel_enter(curthread);
|
2010-08-20 04:15:05 +00:00
|
|
|
ret = __sys_fcntl(fd, cmd, va_arg(ap, void *));
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
|
|
|
} else {
|
2009-03-09 05:54:43 +00:00
|
|
|
ret = __sys_fcntl(fd, cmd, va_arg(ap, void *));
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
va_end(ap);
|
|
|
|
|
2005-04-02 01:20:00 +00:00
|
|
|
return (ret);
|
2004-06-27 10:01:35 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled after system call.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_fsync(int fd)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter2(curthread, 0);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_fsync(fd);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, 1);
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2005-04-02 01:20:00 +00:00
|
|
|
return (ret);
|
2004-09-16 13:55:46 +00:00
|
|
|
}
|
|
|
|
|
2016-08-16 08:27:03 +00:00
|
|
|
static int
|
|
|
|
__thr_fdatasync(int fd)
|
|
|
|
{
|
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
curthread = _get_curthread();
|
|
|
|
_thr_cancel_enter2(curthread, 0);
|
|
|
|
ret = __sys_fdatasync(fd);
|
|
|
|
_thr_cancel_leave(curthread, 1);
|
|
|
|
|
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled after system call.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_msync(void *addr, size_t len, int flags)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter2(curthread, 0);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_msync(addr, len, flags);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, 1);
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
2017-03-19 00:51:12 +00:00
|
|
|
static int
|
|
|
|
__thr_clock_nanosleep(clockid_t clock_id, int flags,
|
|
|
|
const struct timespec *time_to_sleep, struct timespec *time_remaining)
|
|
|
|
{
|
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
curthread = _get_curthread();
|
|
|
|
_thr_cancel_enter(curthread);
|
|
|
|
ret = __sys_clock_nanosleep(clock_id, flags, time_to_sleep,
|
|
|
|
time_remaining);
|
|
|
|
_thr_cancel_leave(curthread, 1);
|
|
|
|
|
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_nanosleep(const struct timespec *time_to_sleep,
|
2005-04-02 01:20:00 +00:00
|
|
|
struct timespec *time_remaining)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
2006-11-24 09:57:38 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_nanosleep(time_to_sleep, time_remaining);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, 1);
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2005-04-02 01:20:00 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* If the thread is canceled, file is not opened.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_openat(int fd, const char *path, int flags, ...)
|
2009-10-11 20:19:45 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
|
|
|
int mode, ret;
|
2009-10-11 20:19:45 +00:00
|
|
|
va_list ap;
|
|
|
|
|
|
|
|
|
|
|
|
/* Check if the file is being created: */
|
2015-01-03 18:38:46 +00:00
|
|
|
if ((flags & O_CREAT) != 0) {
|
2009-10-11 20:19:45 +00:00
|
|
|
/* Get the creation mode: */
|
|
|
|
va_start(ap, flags);
|
|
|
|
mode = va_arg(ap, int);
|
|
|
|
va_end(ap);
|
2015-01-03 18:38:46 +00:00
|
|
|
} else {
|
|
|
|
mode = 0;
|
2009-10-11 20:19:45 +00:00
|
|
|
}
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2009-10-11 20:19:45 +00:00
|
|
|
ret = __sys_openat(fd, path, flags, mode);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2009-10-11 20:19:45 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2009-10-11 20:19:45 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call returns something,
|
|
|
|
* the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_poll(struct pollfd *fds, unsigned int nfds, int timeout)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2003-04-01 03:46:29 +00:00
|
|
|
int ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_poll(fds, nfds, timeout);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
2015-04-18 21:35:41 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call returns something,
|
|
|
|
* the thread is not canceled.
|
|
|
|
*/
|
|
|
|
static int
|
|
|
|
__thr_ppoll(struct pollfd pfd[], nfds_t nfds, const struct timespec *
|
|
|
|
timeout, const sigset_t *newsigmask)
|
|
|
|
{
|
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
curthread = _get_curthread();
|
|
|
|
_thr_cancel_enter(curthread);
|
|
|
|
ret = __sys_ppoll(pfd, nfds, timeout, newsigmask);
|
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
|
|
|
|
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call returns something,
|
|
|
|
* the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_pselect(int count, fd_set *rfds, fd_set *wfds, fd_set *efds,
|
2003-04-01 03:46:29 +00:00
|
|
|
const struct timespec *timo, const sigset_t *mask)
|
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2003-04-01 03:46:29 +00:00
|
|
|
int ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2009-10-27 10:55:34 +00:00
|
|
|
ret = __sys_pselect(count, rfds, wfds, efds, timo, mask);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2003-04-01 03:46:29 +00:00
|
|
|
|
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
Make kevent(2) a cancellation point.
Note that to cancel blocked kevent(2) call, changelist must be empty,
since we cannot cancel a call which already made changes to the
process state. And in reverse, call which only makes changes to the
kqueue state, without waiting for an event, is not cancellable. This
makes a natural usage model to migrate kqueue loop to support
cancellation, where existing single kevent(2) call must be split into
two: first uncancellable update of kqueue, then cancellable wait for
events.
Note that this is ABI-incompatible change, but it is believed that
there is no cancel-safe code that relies on kevent(2) not being a
cancellation point. Option to preserve the ABI would be to keep
kevent(2) as is, but add new call with flags to specify cancellation
behaviour, which only value seems to add complications.
Suggested and reviewed by: jilles
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
2015-03-29 19:14:41 +00:00
|
|
|
static int
|
|
|
|
__thr_kevent(int kq, const struct kevent *changelist, int nchanges,
|
|
|
|
struct kevent *eventlist, int nevents, const struct timespec *timeout)
|
|
|
|
{
|
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (nevents == 0) {
|
|
|
|
/*
|
|
|
|
* No blocking, do not make the call cancellable.
|
|
|
|
*/
|
|
|
|
return (__sys_kevent(kq, changelist, nchanges, eventlist,
|
|
|
|
nevents, timeout));
|
|
|
|
}
|
|
|
|
curthread = _get_curthread();
|
|
|
|
_thr_cancel_enter(curthread);
|
|
|
|
ret = __sys_kevent(kq, changelist, nchanges, eventlist, nevents,
|
|
|
|
timeout);
|
|
|
|
_thr_cancel_leave(curthread, ret == -1 && nchanges == 0);
|
|
|
|
|
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call got some data,
|
|
|
|
* the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static ssize_t
|
|
|
|
__thr_read(int fd, void *buf, size_t nbytes)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2003-04-01 03:46:29 +00:00
|
|
|
ssize_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_read(fd, buf, nbytes);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call got some data,
|
|
|
|
* the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static ssize_t
|
|
|
|
__thr_readv(int fd, const struct iovec *iov, int iovcnt)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2003-04-01 03:46:29 +00:00
|
|
|
ssize_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_readv(fd, iov, iovcnt);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call got some data,
|
|
|
|
* the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static ssize_t
|
|
|
|
__thr_recvfrom(int s, void *b, size_t l, int f, struct sockaddr *from,
|
2004-09-16 13:55:46 +00:00
|
|
|
socklen_t *fl)
|
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2004-09-16 13:55:46 +00:00
|
|
|
ssize_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2004-09-16 13:55:46 +00:00
|
|
|
ret = __sys_recvfrom(s, b, l, f, from, fl);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2004-09-16 13:55:46 +00:00
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call got some data,
|
|
|
|
* the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static ssize_t
|
|
|
|
__thr_recvmsg(int s, struct msghdr *m, int f)
|
2004-09-16 13:55:46 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2004-09-16 13:55:46 +00:00
|
|
|
ssize_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2004-09-16 13:55:46 +00:00
|
|
|
ret = __sys_recvmsg(s, m, f);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2004-09-16 13:55:46 +00:00
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call returns something,
|
|
|
|
* the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_select(int numfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
|
2003-04-01 03:46:29 +00:00
|
|
|
struct timeval *timeout)
|
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2003-04-01 03:46:29 +00:00
|
|
|
int ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_select(numfds, readfds, writefds, exceptfds, timeout);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call sent
|
|
|
|
* data, the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static ssize_t
|
|
|
|
__thr_sendmsg(int s, const struct msghdr *m, int f)
|
2004-09-16 13:55:46 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2004-09-16 13:55:46 +00:00
|
|
|
ssize_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2004-09-16 13:55:46 +00:00
|
|
|
ret = __sys_sendmsg(s, m, f);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret <= 0);
|
2004-09-16 13:55:46 +00:00
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call sent some
|
|
|
|
* data, the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static ssize_t
|
|
|
|
__thr_sendto(int s, const void *m, size_t l, int f, const struct sockaddr *t,
|
2004-09-16 13:55:46 +00:00
|
|
|
socklen_t tl)
|
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2004-09-16 13:55:46 +00:00
|
|
|
ssize_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2004-09-16 13:55:46 +00:00
|
|
|
ret = __sys_sendto(s, m, l, f, t, tl);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret <= 0);
|
2004-09-16 13:55:46 +00:00
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_system(const char *string)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
2006-11-24 09:57:38 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2015-01-03 18:38:46 +00:00
|
|
|
ret = __libc_system(string);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, 1);
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* If thread is canceled, the system call is not completed,
|
|
|
|
* this means not all bytes were drained.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static int
|
|
|
|
__thr_tcdrain(int fd)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
|
|
|
int ret;
|
2003-04-01 03:46:29 +00:00
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2015-01-03 18:38:46 +00:00
|
|
|
ret = __libc_tcdrain(fd);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret == -1);
|
2005-04-02 01:20:00 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call returns
|
|
|
|
* a child pid, the thread is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static pid_t
|
|
|
|
__thr_wait4(pid_t pid, int *status, int options, struct rusage *rusage)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2003-04-01 03:46:29 +00:00
|
|
|
pid_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2006-07-25 12:50:05 +00:00
|
|
|
ret = __sys_wait4(pid, status, options, rusage);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, ret <= 0);
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
2015-04-18 21:35:41 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the system call returns
|
|
|
|
* a child pid, the thread is not canceled.
|
|
|
|
*/
|
|
|
|
static pid_t
|
|
|
|
__thr_wait6(idtype_t idtype, id_t id, int *status, int options,
|
|
|
|
struct __wrusage *ru, siginfo_t *infop)
|
|
|
|
{
|
|
|
|
struct pthread *curthread;
|
|
|
|
pid_t ret;
|
|
|
|
|
|
|
|
curthread = _get_curthread();
|
|
|
|
_thr_cancel_enter(curthread);
|
|
|
|
ret = __sys_wait6(idtype, id, status, options, ru, infop);
|
|
|
|
_thr_cancel_leave(curthread, ret <= 0);
|
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the thread wrote some data,
|
|
|
|
* it is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static ssize_t
|
|
|
|
__thr_write(int fd, const void *buf, size_t nbytes)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2003-04-01 03:46:29 +00:00
|
|
|
ssize_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_write(fd, buf, nbytes);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, (ret <= 0));
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|
|
|
|
|
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
2010-08-20 05:15:39 +00:00
|
|
|
/*
|
|
|
|
* Cancellation behavior:
|
|
|
|
* Thread may be canceled at start, but if the thread wrote some data,
|
|
|
|
* it is not canceled.
|
|
|
|
*/
|
2015-01-03 18:38:46 +00:00
|
|
|
static ssize_t
|
|
|
|
__thr_writev(int fd, const struct iovec *iov, int iovcnt)
|
2003-04-01 03:46:29 +00:00
|
|
|
{
|
2015-01-03 18:38:46 +00:00
|
|
|
struct pthread *curthread;
|
2003-04-01 03:46:29 +00:00
|
|
|
ssize_t ret;
|
|
|
|
|
2015-01-03 18:38:46 +00:00
|
|
|
curthread = _get_curthread();
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_enter(curthread);
|
2003-04-01 03:46:29 +00:00
|
|
|
ret = __sys_writev(fd, iov, iovcnt);
|
Add signal handler wrapper, the reason to add it becauses there are
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
2010-09-01 02:18:33 +00:00
|
|
|
_thr_cancel_leave(curthread, (ret <= 0));
|
2015-01-03 18:38:46 +00:00
|
|
|
return (ret);
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
__thr_interpose_libc(void)
|
|
|
|
{
|
|
|
|
|
2015-01-05 01:06:54 +00:00
|
|
|
__set_error_selector(__error_threaded);
|
2015-01-03 18:38:46 +00:00
|
|
|
#define SLOT(name) \
|
|
|
|
*(__libc_interposing_slot(INTERPOS_##name)) = \
|
|
|
|
(interpos_func_t)__thr_##name;
|
|
|
|
SLOT(accept);
|
|
|
|
SLOT(accept4);
|
|
|
|
SLOT(aio_suspend);
|
|
|
|
SLOT(close);
|
|
|
|
SLOT(connect);
|
|
|
|
SLOT(fcntl);
|
|
|
|
SLOT(fsync);
|
|
|
|
SLOT(fork);
|
|
|
|
SLOT(msync);
|
|
|
|
SLOT(nanosleep);
|
|
|
|
SLOT(openat);
|
|
|
|
SLOT(poll);
|
|
|
|
SLOT(pselect);
|
|
|
|
SLOT(read);
|
|
|
|
SLOT(readv);
|
|
|
|
SLOT(recvfrom);
|
|
|
|
SLOT(recvmsg);
|
|
|
|
SLOT(select);
|
|
|
|
SLOT(sendmsg);
|
|
|
|
SLOT(sendto);
|
|
|
|
SLOT(setcontext);
|
|
|
|
SLOT(sigaction);
|
|
|
|
SLOT(sigprocmask);
|
|
|
|
SLOT(sigsuspend);
|
|
|
|
SLOT(sigwait);
|
|
|
|
SLOT(sigtimedwait);
|
|
|
|
SLOT(sigwaitinfo);
|
|
|
|
SLOT(swapcontext);
|
|
|
|
SLOT(system);
|
|
|
|
SLOT(tcdrain);
|
|
|
|
SLOT(wait4);
|
|
|
|
SLOT(write);
|
|
|
|
SLOT(writev);
|
2015-02-14 11:47:40 +00:00
|
|
|
SLOT(spinlock);
|
|
|
|
SLOT(spinunlock);
|
Make kevent(2) a cancellation point.
Note that to cancel blocked kevent(2) call, changelist must be empty,
since we cannot cancel a call which already made changes to the
process state. And in reverse, call which only makes changes to the
kqueue state, without waiting for an event, is not cancellable. This
makes a natural usage model to migrate kqueue loop to support
cancellation, where existing single kevent(2) call must be split into
two: first uncancellable update of kqueue, then cancellable wait for
events.
Note that this is ABI-incompatible change, but it is believed that
there is no cancel-safe code that relies on kevent(2) not being a
cancellation point. Option to preserve the ABI would be to keep
kevent(2) as is, but add new call with flags to specify cancellation
behaviour, which only value seems to add complications.
Suggested and reviewed by: jilles
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
2015-03-29 19:14:41 +00:00
|
|
|
SLOT(kevent);
|
2015-04-18 21:35:41 +00:00
|
|
|
SLOT(wait6);
|
|
|
|
SLOT(ppoll);
|
2016-02-08 19:24:13 +00:00
|
|
|
SLOT(map_stacks_exec);
|
2016-08-16 08:27:03 +00:00
|
|
|
SLOT(fdatasync);
|
2017-03-19 00:51:12 +00:00
|
|
|
SLOT(clock_nanosleep);
|
2021-01-10 19:22:49 +00:00
|
|
|
SLOT(pdfork);
|
2015-01-03 18:38:46 +00:00
|
|
|
#undef SLOT
|
|
|
|
*(__libc_interposing_slot(
|
|
|
|
INTERPOS__pthread_mutex_init_calloc_cb)) =
|
|
|
|
(interpos_func_t)_pthread_mutex_init_calloc_cb;
|
2003-04-01 03:46:29 +00:00
|
|
|
}
|