mirror_zfs/lib/libspl/include/sys/thread.h
Rob Norris 4d451bae8a libspl: hide global data objects
Currently libspl is a static archive that is linked into multiple shared
objects, which then re-export its symbols. We intend to fix this soon.

For the moment though, most programs shipped with OpenZFS depend on two
or more of these shared objects, and see the same symbols twice. For
functions this is not a problem, as they do not have any mutable state
and so the linker can simply select the first one and use that for all.

For global data objects however, each shared object will have direct
(non-relocatable) references to its own instance of the symbol, such
that changes on one will not necessarily be seen by the other. While
this shouldn't be a problem in practice as these reexported interfaces
are not supposed to be used, they are technically undefined behaviour in
C (C17 6.9.2) and are reported by ASAN as a violation of C++'s "One
Definition Rule".

To fix this, we hide these globals inside their compilation units, and
add access functions and macros as appropriate to preserve the existing
API (though not ABI).

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #17861
2025-11-12 10:04:22 -08:00

80 lines
2.4 KiB
C

// SPDX-License-Identifier: CDDL-1.0
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or https://opensource.org/licenses/CDDL-1.0.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2012, 2018 by Delphix. All rights reserved.
* Copyright (c) 2012, Joyent, Inc. All rights reserved.
*/
#ifndef _SYS_THREAD_H
#define _SYS_THREAD_H
#include <pthread.h>
/*
* Threads.
*/
typedef pthread_t kthread_t;
#define TS_RUN 0x00000002
#define TS_JOINABLE 0x00000004
#define curthread ((void *)(uintptr_t)pthread_self())
#define getcomm() "unknown"
#define thread_create_named(name, stk, stksize, func, arg, len, \
pp, state, pri) \
zk_thread_create(name, func, arg, stksize, state)
#define thread_create(stk, stksize, func, arg, len, pp, state, pri) \
zk_thread_create(#func, func, arg, stksize, state)
#define thread_exit() pthread_exit(NULL)
#define thread_join(t) pthread_join((pthread_t)(t), NULL)
#define newproc(f, a, cid, pri, ctp, pid) (ENOSYS)
/*
* Check if the current thread is a memory reclaim thread.
* Always returns false in userspace (no memory reclaim thread).
*/
#define current_is_reclaim_thread() (0)
/* in libzpool, p0 exists only to have its address taken */
typedef void (proc_t)(void);
extern void p0(void);
#define curproc (&p0)
#define PS_NONE -1
extern kthread_t *zk_thread_create(const char *name, void (*func)(void *),
void *arg, size_t stksize, int state);
#define issig() (FALSE)
#define KPREEMPT_SYNC (-1)
#define kpreempt(x) sched_yield()
#define kpreempt_disable() ((void)0)
#define kpreempt_enable() ((void)0)
#endif /* _SYS_THREAD_H */