9b0f1823b5
now type sema_t is a structure which can be put in a shared memory area, and multiple processes can operate it concurrently. User can either use mmap(MAP_SHARED) + sem_init(pshared=1) or use sem_open() to initialize a shared semaphore. Named semaphore uses file system and is located in /tmp directory, and its file name is prefixed with 'SEMD', so now it is chroot or jail friendly. In simplist cases, both for named and un-named semaphore, userland code does not have to enter kernel to reduce/increase semaphore's count. The semaphore is designed to be crash-safe, it means even if an application is crashed in the middle of operating semaphore, the semaphore state is still safely recovered by later use, there is no waiter counter maintained by userland code. The main semaphore code is in libc and libthr only has some necessary stubs, this makes it possible that a non-threaded application can use semaphore without linking to thread library. Old semaphore implementation is kept libc to maintain binary compatibility. The kernel ksem API is no longer used in the new implemenation. Discussed on: threads@
308 lines
13 KiB
C
308 lines
13 KiB
C
/*
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* Copyright (c) 2001 Daniel Eischen <deischen@FreeBSD.org>.
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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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*
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* THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS''
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* AND 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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <signal.h>
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#include <pthread.h>
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#include <stdlib.h>
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#include "libc_private.h"
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/*
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* Weak symbols: All libc internal usage of these functions should
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* use the weak symbol versions (_pthread_XXX). If libpthread is
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* linked, it will override these functions with (non-weak) routines.
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* The _pthread_XXX functions are provided solely for internal libc
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* usage to avoid unwanted cancellation points and to differentiate
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* between application locks and libc locks (threads holding the
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* latter can't be allowed to exit/terminate).
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*/
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/* Define a null pthread structure just to satisfy _pthread_self. */
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struct pthread {
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};
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static struct pthread main_thread;
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static int stub_main(void);
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static void *stub_null(void);
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static struct pthread *stub_self(void);
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static int stub_zero(void);
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static int stub_true(void);
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static void stub_exit(void);
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#define PJT_DUAL_ENTRY(entry) \
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(pthread_func_t)entry, (pthread_func_t)entry
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pthread_func_entry_t __thr_jtable[PJT_MAX] = {
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATFORK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_DESTROY */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_GETDETACHSTATE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_GETGUARDSIZE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_GETINHERITSCHED */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_GETSCHEDPARAM */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_GETSCHEDPOLICY */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_GETSCOPE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_GETSTACKADDR */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_GETSTACKSIZE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_INIT */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_SETDETACHSTATE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_SETGUARDSIZE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_SETINHERITSCHED */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_SETSCHEDPARAM */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_SETSCHEDPOLICY */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_SETSCOPE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_SETSTACKADDR */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ATTR_SETSTACKSIZE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_CANCEL */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_CLEANUP_POP */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_CLEANUP_PUSH */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_COND_BROADCAST */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_COND_DESTROY */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_COND_INIT */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_COND_SIGNAL */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_COND_TIMEDWAIT */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_COND_WAIT */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_DETACH */
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{PJT_DUAL_ENTRY(stub_true)}, /* PJT_EQUAL */
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{PJT_DUAL_ENTRY(stub_exit)}, /* PJT_EXIT */
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{PJT_DUAL_ENTRY(stub_null)}, /* PJT_GETSPECIFIC */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_JOIN */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_KEY_CREATE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_KEY_DELETE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_KILL */
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{PJT_DUAL_ENTRY(stub_main)}, /* PJT_MAIN_NP */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEXATTR_DESTROY */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEXATTR_INIT */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEXATTR_SETTYPE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEX_DESTROY */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEX_INIT */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEX_LOCK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEX_TRYLOCK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEX_UNLOCK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ONCE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_DESTROY */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_INIT */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_RDLOCK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_TRYRDLOCK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_TRYWRLOCK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_UNLOCK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_WRLOCK */
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{PJT_DUAL_ENTRY(stub_self)}, /* PJT_SELF */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_SETCANCELSTATE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_SETCANCELTYPE */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_SETSPECIFIC */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_SIGMASK */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_TESTCANCEL */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_CLEANUP_POP_IMP */
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{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_CLEANUP_PUSH_IMP */
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};
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/*
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* Weak aliases for exported (pthread_*) and internal (_pthread_*) routines.
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*/
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#define WEAK_REF(sym, alias) __weak_reference(sym, alias)
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#define FUNC_TYPE(name) __CONCAT(name, _func_t)
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#define FUNC_INT(name) __CONCAT(name, _int)
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#define FUNC_EXP(name) __CONCAT(name, _exp)
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#define STUB_FUNC(name, idx, ret) \
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static ret FUNC_EXP(name)(void) __used; \
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static ret FUNC_INT(name)(void) __used; \
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WEAK_REF(FUNC_EXP(name), name); \
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WEAK_REF(FUNC_INT(name), __CONCAT(_, name)); \
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typedef ret (*FUNC_TYPE(name))(void); \
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static ret FUNC_EXP(name)(void) \
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{ \
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FUNC_TYPE(name) func; \
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func = (FUNC_TYPE(name))__thr_jtable[idx][0]; \
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return (func()); \
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} \
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static ret FUNC_INT(name)(void) \
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{ \
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FUNC_TYPE(name) func; \
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func = (FUNC_TYPE(name))__thr_jtable[idx][1]; \
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return (func()); \
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}
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#define STUB_FUNC1(name, idx, ret, p0_type) \
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static ret FUNC_EXP(name)(p0_type) __used; \
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static ret FUNC_INT(name)(p0_type) __used; \
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WEAK_REF(FUNC_EXP(name), name); \
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WEAK_REF(FUNC_INT(name), __CONCAT(_, name)); \
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typedef ret (*FUNC_TYPE(name))(p0_type); \
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static ret FUNC_EXP(name)(p0_type p0) \
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{ \
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FUNC_TYPE(name) func; \
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func = (FUNC_TYPE(name))__thr_jtable[idx][0]; \
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return (func(p0)); \
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} \
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static ret FUNC_INT(name)(p0_type p0) \
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{ \
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FUNC_TYPE(name) func; \
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func = (FUNC_TYPE(name))__thr_jtable[idx][1]; \
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return (func(p0)); \
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}
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#define STUB_FUNC2(name, idx, ret, p0_type, p1_type) \
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static ret FUNC_EXP(name)(p0_type, p1_type) __used; \
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static ret FUNC_INT(name)(p0_type, p1_type) __used; \
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WEAK_REF(FUNC_EXP(name), name); \
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WEAK_REF(FUNC_INT(name), __CONCAT(_, name)); \
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typedef ret (*FUNC_TYPE(name))(p0_type, p1_type); \
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static ret FUNC_EXP(name)(p0_type p0, p1_type p1) \
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{ \
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FUNC_TYPE(name) func; \
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func = (FUNC_TYPE(name))__thr_jtable[idx][0]; \
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return (func(p0, p1)); \
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} \
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static ret FUNC_INT(name)(p0_type p0, p1_type p1) \
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{ \
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FUNC_TYPE(name) func; \
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func = (FUNC_TYPE(name))__thr_jtable[idx][1]; \
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return (func(p0, p1)); \
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}
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#define STUB_FUNC3(name, idx, ret, p0_type, p1_type, p2_type) \
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static ret FUNC_EXP(name)(p0_type, p1_type, p2_type) __used; \
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static ret FUNC_INT(name)(p0_type, p1_type, p2_type) __used; \
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WEAK_REF(FUNC_EXP(name), name); \
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WEAK_REF(FUNC_INT(name), __CONCAT(_, name)); \
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typedef ret (*FUNC_TYPE(name))(p0_type, p1_type, p2_type); \
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static ret FUNC_EXP(name)(p0_type p0, p1_type p1, p2_type p2) \
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{ \
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FUNC_TYPE(name) func; \
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func = (FUNC_TYPE(name))__thr_jtable[idx][0]; \
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return (func(p0, p1, p2)); \
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} \
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static ret FUNC_INT(name)(p0_type p0, p1_type p1, p2_type p2) \
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{ \
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FUNC_TYPE(name) func; \
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func = (FUNC_TYPE(name))__thr_jtable[idx][1]; \
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return (func(p0, p1, p2)); \
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}
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STUB_FUNC1(pthread_cond_broadcast, PJT_COND_BROADCAST, int, void *)
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STUB_FUNC1(pthread_cond_destroy, PJT_COND_DESTROY, int, void *)
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STUB_FUNC2(pthread_cond_init, PJT_COND_INIT, int, void *, void *)
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STUB_FUNC1(pthread_cond_signal, PJT_COND_SIGNAL, int, void *)
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STUB_FUNC2(pthread_cond_wait, PJT_COND_WAIT, int, void *, void *)
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STUB_FUNC1(pthread_getspecific, PJT_GETSPECIFIC, void *, pthread_key_t)
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STUB_FUNC2(pthread_key_create, PJT_KEY_CREATE, int, void *, void *)
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STUB_FUNC1(pthread_key_delete, PJT_KEY_DELETE, int, pthread_key_t)
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STUB_FUNC(pthread_main_np, PJT_MAIN_NP, int)
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STUB_FUNC1(pthread_mutex_destroy, PJT_MUTEX_DESTROY, int, void *)
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STUB_FUNC2(pthread_mutex_init, PJT_MUTEX_INIT, int, void *, void *)
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STUB_FUNC1(pthread_mutex_lock, PJT_MUTEX_LOCK, int, void *)
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STUB_FUNC1(pthread_mutex_trylock, PJT_MUTEX_TRYLOCK, int, void *)
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STUB_FUNC1(pthread_mutex_unlock, PJT_MUTEX_UNLOCK, int, void *)
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STUB_FUNC1(pthread_mutexattr_destroy, PJT_MUTEXATTR_DESTROY, int, void *)
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STUB_FUNC1(pthread_mutexattr_init, PJT_MUTEXATTR_INIT, int, void *)
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STUB_FUNC2(pthread_mutexattr_settype, PJT_MUTEXATTR_SETTYPE, int, void *, int)
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STUB_FUNC2(pthread_once, PJT_ONCE, int, void *, void *)
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STUB_FUNC1(pthread_rwlock_destroy, PJT_RWLOCK_DESTROY, int, void *)
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STUB_FUNC2(pthread_rwlock_init, PJT_RWLOCK_INIT, int, void *, void *)
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STUB_FUNC1(pthread_rwlock_rdlock, PJT_RWLOCK_RDLOCK, int, void *)
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STUB_FUNC1(pthread_rwlock_tryrdlock, PJT_RWLOCK_TRYRDLOCK, int, void *)
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STUB_FUNC1(pthread_rwlock_trywrlock, PJT_RWLOCK_TRYWRLOCK, int, void *)
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STUB_FUNC1(pthread_rwlock_unlock, PJT_RWLOCK_UNLOCK, int, void *)
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STUB_FUNC1(pthread_rwlock_wrlock, PJT_RWLOCK_WRLOCK, int, void *)
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STUB_FUNC(pthread_self, PJT_SELF, pthread_t)
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STUB_FUNC2(pthread_setspecific, PJT_SETSPECIFIC, int, pthread_key_t, void *)
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STUB_FUNC3(pthread_sigmask, PJT_SIGMASK, int, int, void *, void *)
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STUB_FUNC3(pthread_atfork, PJT_ATFORK, int, void *, void *, void*)
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STUB_FUNC1(pthread_attr_destroy, PJT_ATTR_DESTROY, int, void *);
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STUB_FUNC2(pthread_attr_getdetachstate, PJT_ATTR_GETDETACHSTATE, int, void *, void *)
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STUB_FUNC2(pthread_attr_getguardsize, PJT_ATTR_GETGUARDSIZE, int, void *, void *)
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STUB_FUNC2(pthread_attr_getstackaddr, PJT_ATTR_GETSTACKADDR, int, void *, void *)
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STUB_FUNC2(pthread_attr_getstacksize, PJT_ATTR_GETSTACKSIZE, int, void *, void *)
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STUB_FUNC2(pthread_attr_getinheritsched, PJT_ATTR_GETINHERITSCHED, int, void *, void *)
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STUB_FUNC2(pthread_attr_getschedparam, PJT_ATTR_GETSCHEDPARAM, int, void *, void *)
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STUB_FUNC2(pthread_attr_getschedpolicy, PJT_ATTR_GETSCHEDPOLICY, int, void *, void *)
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STUB_FUNC2(pthread_attr_getscope, PJT_ATTR_GETSCOPE, int, void *, void *)
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STUB_FUNC1(pthread_attr_init, PJT_ATTR_INIT, int, void *)
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STUB_FUNC2(pthread_attr_setdetachstate, PJT_ATTR_SETDETACHSTATE, int, void *, int)
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STUB_FUNC2(pthread_attr_setguardsize, PJT_ATTR_SETGUARDSIZE, int, void *, size_t)
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STUB_FUNC2(pthread_attr_setstackaddr, PJT_ATTR_SETSTACKADDR, int, void *, void *)
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STUB_FUNC2(pthread_attr_setstacksize, PJT_ATTR_SETSTACKSIZE, int, void *, size_t)
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STUB_FUNC2(pthread_attr_setinheritsched, PJT_ATTR_SETINHERITSCHED, int, void *, int)
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STUB_FUNC2(pthread_attr_setschedparam, PJT_ATTR_SETSCHEDPARAM, int, void *, void *)
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STUB_FUNC2(pthread_attr_setschedpolicy, PJT_ATTR_SETSCHEDPOLICY, int, void *, int)
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STUB_FUNC2(pthread_attr_setscope, PJT_ATTR_SETSCOPE, int, void *, int)
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STUB_FUNC1(pthread_cancel, PJT_CANCEL, int, void *)
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STUB_FUNC1(pthread_cleanup_pop, PJT_CLEANUP_POP, int, int)
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STUB_FUNC2(pthread_cleanup_push, PJT_CLEANUP_PUSH, void, void *, void *)
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STUB_FUNC3(pthread_cond_timedwait, PJT_COND_TIMEDWAIT, int, void *, void *, void *)
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STUB_FUNC1(pthread_detach, PJT_DETACH, int, void *)
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STUB_FUNC2(pthread_equal, PJT_EQUAL, int, void *, void *)
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STUB_FUNC1(pthread_exit, PJT_EXIT, void, void *)
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STUB_FUNC2(pthread_join, PJT_JOIN, int, void *, void *)
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STUB_FUNC2(pthread_kill, PJT_KILL, int, void *, int)
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STUB_FUNC2(pthread_setcancelstate, PJT_SETCANCELSTATE, int, int, void *)
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STUB_FUNC2(pthread_setcanceltype, PJT_SETCANCELTYPE, int, int, void *)
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STUB_FUNC(pthread_testcancel, PJT_TESTCANCEL, void)
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STUB_FUNC1(__pthread_cleanup_pop_imp, PJT_CLEANUP_POP_IMP, int, int)
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STUB_FUNC2(__pthread_cleanup_push_imp, PJT_CLEANUP_PUSH_IMP, void, void*, void *);
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static int
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stub_zero(void)
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{
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return (0);
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}
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static void *
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stub_null(void)
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{
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return (NULL);
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}
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static struct pthread *
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stub_self(void)
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{
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return (&main_thread);
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}
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static int
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stub_main(void)
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{
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return (-1);
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}
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static int
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stub_true(void)
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{
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return (1);
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}
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static void
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stub_exit(void)
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{
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exit(0);
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}
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