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c8f9421298
The implementation is extremely similar to the nptl implementation, but with slight differences in the futex interface. This fixes some of BZ 25521.
368 lines
12 KiB
C
368 lines
12 KiB
C
/* Internal defenitions for pthreads library.
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Copyright (C) 2000-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _PT_INTERNAL_H
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#define _PT_INTERNAL_H 1
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#include <pthread.h>
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#include <stddef.h>
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#include <sched.h>
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#include <signal.h>
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#include <assert.h>
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#include <bits/types/res_state.h>
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#include <atomic.h>
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#include <pt-key.h>
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#include <pt-sysdep.h>
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#include <pt-machdep.h>
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#if IS_IN (libpthread)
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# include <ldsodefs.h>
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#endif
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#include <tls.h>
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/* Thread state. */
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enum pthread_state
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{
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/* The thread is running and joinable. */
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PTHREAD_JOINABLE = 0,
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/* The thread is running and detached. */
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PTHREAD_DETACHED,
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/* A joinable thread exited and its return code is available. */
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PTHREAD_EXITED,
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/* The thread structure is unallocated and available for reuse. */
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PTHREAD_TERMINATED
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};
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#ifndef PTHREAD_KEY_MEMBERS
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# define PTHREAD_KEY_MEMBERS
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#endif
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#ifndef PTHREAD_SYSDEP_MEMBERS
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# define PTHREAD_SYSDEP_MEMBERS
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#endif
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/* This structure describes a POSIX thread. */
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struct __pthread
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{
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/* Thread ID. */
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pthread_t thread;
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unsigned int nr_refs; /* Detached threads have a self reference only,
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while joinable threads have two references.
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These are used to keep the structure valid at
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thread destruction. Detaching/joining a thread
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drops a reference. */
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/* Cancellation. */
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pthread_mutex_t cancel_lock; /* Protect cancel_xxx members. */
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void (*cancel_hook) (void *); /* Called to unblock a thread blocking
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in a cancellation point (namely,
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__pthread_cond_timedwait_internal). */
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void *cancel_hook_arg;
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int cancel_state;
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int cancel_type;
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int cancel_pending;
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/* Thread stack. */
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void *stackaddr;
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size_t stacksize;
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size_t guardsize;
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int stack; /* Nonzero if the stack was allocated. */
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/* Exit status. */
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void *status;
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/* Thread state. */
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enum pthread_state state;
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pthread_mutex_t state_lock; /* Locks the state. */
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pthread_cond_t state_cond; /* Signalled when the state changes. */
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/* Resolver state. */
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struct __res_state res_state;
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/* Indicates whether is a C11 thread created by thrd_creat. */
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bool c11;
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/* Initial sigset for the thread. */
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sigset_t init_sigset;
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/* Thread context. */
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struct pthread_mcontext mcontext;
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PTHREAD_KEY_MEMBERS
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PTHREAD_SYSDEP_MEMBERS
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tcbhead_t *tcb;
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/* Queue links. Since PREVP is used to determine if a thread has been
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awaken, it must be protected by the queue lock. */
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struct __pthread *next, **prevp;
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};
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/* Enqueue an element THREAD on the queue *HEAD. */
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static inline void
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__pthread_enqueue (struct __pthread **head, struct __pthread *thread)
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{
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assert (thread->prevp == 0);
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thread->next = *head;
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thread->prevp = head;
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if (*head)
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(*head)->prevp = &thread->next;
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*head = thread;
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}
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/* Dequeue the element THREAD from the queue it is connected to. */
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static inline void
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__pthread_dequeue (struct __pthread *thread)
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{
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assert (thread);
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assert (thread->prevp);
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if (thread->next)
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thread->next->prevp = thread->prevp;
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*thread->prevp = thread->next;
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thread->prevp = 0;
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}
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/* Iterate over QUEUE storing each element in ELEMENT. */
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#define __pthread_queue_iterate(queue, element) \
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for (struct __pthread *__pdi_next = (queue); \
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((element) = __pdi_next) \
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&& ((__pdi_next = __pdi_next->next), \
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1); \
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)
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/* Iterate over QUEUE dequeuing each element, storing it in
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ELEMENT. */
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#define __pthread_dequeuing_iterate(queue, element) \
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for (struct __pthread *__pdi_next = (queue); \
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((element) = __pdi_next) \
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&& ((__pdi_next = __pdi_next->next), \
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((element)->prevp = 0), \
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1); \
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)
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/* The total number of threads currently active. */
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extern unsigned int __pthread_total;
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/* The total number of thread IDs currently in use, or on the list of
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available thread IDs. */
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extern int __pthread_num_threads;
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/* Concurrency hint. */
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extern int __pthread_concurrency;
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/* Array of __pthread structures and its lock. Indexed by the pthread
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id minus one. (Why not just use the pthread id? Because some
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brain-dead users of the pthread interface incorrectly assume that 0
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is an invalid pthread id.) */
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extern struct __pthread **__pthread_threads;
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extern int __pthread_max_threads;
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extern pthread_rwlock_t __pthread_threads_lock;
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#define __pthread_getid(thread) \
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({ struct __pthread *__t = NULL; \
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__pthread_rwlock_rdlock (&__pthread_threads_lock); \
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if (thread <= __pthread_max_threads) \
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__t = __pthread_threads[thread - 1]; \
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__pthread_rwlock_unlock (&__pthread_threads_lock); \
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__t; })
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#define __pthread_setid(thread, pthread) \
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__pthread_rwlock_wrlock (&__pthread_threads_lock); \
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__pthread_threads[thread - 1] = pthread; \
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__pthread_rwlock_unlock (&__pthread_threads_lock);
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/* Similar to pthread_self, but returns the thread descriptor instead
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of the thread ID. */
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#ifndef _pthread_self
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extern struct __pthread *_pthread_self (void);
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#endif
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/* Stores the stack of cleanup handlers for the thread. */
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extern __thread struct __pthread_cancelation_handler *__pthread_cleanup_stack;
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/* Initialize the pthreads library. */
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extern void ___pthread_init (void);
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/* Internal version of pthread_create. Rather than return the new
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tid, we return the whole __pthread structure in *PTHREAD. */
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extern int __pthread_create_internal (struct __pthread **__restrict pthread,
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const pthread_attr_t *__restrict attr,
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void *(*start_routine) (void *),
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void *__restrict arg);
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/* Allocate a new thread structure and a pthread thread ID (but not a
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kernel thread or a stack). THREAD has one reference. */
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extern int __pthread_alloc (struct __pthread **thread);
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/* Deallocate the thread structure. This is the dual of
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__pthread_alloc (N.B. it does not call __pthread_stack_dealloc nor
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__pthread_thread_terminate). THREAD loses one reference and is
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released if the reference counter drops to 0. */
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extern void __pthread_dealloc (struct __pthread *thread);
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/* Allocate a stack of size STACKSIZE. The stack base shall be
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returned in *STACKADDR. */
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extern int __pthread_stack_alloc (void **stackaddr, size_t stacksize);
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/* Deallocate the stack STACKADDR of size STACKSIZE. */
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extern void __pthread_stack_dealloc (void *stackaddr, size_t stacksize);
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/* Setup thread THREAD's context. */
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extern int __pthread_setup (struct __pthread *__restrict thread,
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void (*entry_point) (struct __pthread *,
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void *(*)(void *),
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void *),
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void *(*start_routine) (void *),
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void *__restrict arg);
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/* Allocate a kernel thread (and any miscellaneous system dependent
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resources) for THREAD; it must not be placed on the run queue. */
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extern int __pthread_thread_alloc (struct __pthread *thread);
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/* Start THREAD making it eligible to run. */
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extern int __pthread_thread_start (struct __pthread *thread);
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/* Terminate the kernel thread associated with THREAD, and deallocate its
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stack as well as any other kernel resource associated with it.
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In addition, THREAD looses one reference.
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This function can be called by any thread, including the target thread.
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Since some resources that are destroyed along the kernel thread are
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stored in thread-local variables, the conditions required for this
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function to behave correctly are a bit unusual : as long as the target
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thread hasn't been started, any thread can terminate it, but once it
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has started, no other thread can terminate it, so that thread-local
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variables created by that thread are correctly released. */
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extern void __pthread_thread_terminate (struct __pthread *thread);
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/* Called by a thread just before it calls the provided start
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routine. */
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extern void __pthread_startup (void);
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/* Block THREAD. */
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extern void __pthread_block (struct __pthread *thread);
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/* Block THREAD until *ABSTIME is reached. */
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extern error_t __pthread_timedblock (struct __pthread *__restrict thread,
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const struct timespec *__restrict abstime,
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clockid_t clock_id);
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/* Block THREAD with interrupts. */
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extern error_t __pthread_block_intr (struct __pthread *thread);
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/* Block THREAD until *ABSTIME is reached, with interrupts. */
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extern error_t __pthread_timedblock_intr (struct __pthread *__restrict thread,
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const struct timespec *__restrict abstime,
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clockid_t clock_id);
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/* Wakeup THREAD. */
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extern void __pthread_wakeup (struct __pthread *thread);
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/* Perform a cancelation. The CANCEL_LOCK member of the given thread must
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be locked before calling this function, which must unlock it. */
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extern int __pthread_do_cancel (struct __pthread *thread);
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/* Initialize the thread specific data structures. THREAD must be the
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calling thread. */
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extern error_t __pthread_init_specific (struct __pthread *thread);
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/* Call the destructors on all of the thread specific data in THREAD.
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THREAD must be the calling thread. */
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extern void __pthread_destroy_specific (struct __pthread *thread);
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/* Initialize newly create thread *THREAD's signal state data
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structures. */
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extern error_t __pthread_sigstate_init (struct __pthread *thread);
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/* Destroy the signal state data structures associcated with thread
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*THREAD. */
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extern void __pthread_sigstate_destroy (struct __pthread *thread);
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/* Modify thread *THREAD's signal state. */
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extern error_t __pthread_sigstate (struct __pthread *__restrict thread, int how,
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const sigset_t *__restrict set,
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sigset_t *__restrict oset,
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int clear_pending);
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/* If supported, check that MUTEX is locked by the caller. */
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extern int __pthread_mutex_checklocked (pthread_mutex_t *mtx);
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/* Default thread attributes. */
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extern struct __pthread_attr __pthread_default_attr;
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/* Default barrier attributes. */
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extern const struct __pthread_barrierattr __pthread_default_barrierattr;
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/* Default rdlock attributes. */
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extern const struct __pthread_rwlockattr __pthread_default_rwlockattr;
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/* Default condition attributes. */
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extern const struct __pthread_condattr __pthread_default_condattr;
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/* Semaphore encoding.
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See nptl implementation for the details. */
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struct new_sem
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{
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#if __HAVE_64B_ATOMICS
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/* The data field holds both value (in the least-significant 32 bits) and
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nwaiters. */
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# if __BYTE_ORDER == __LITTLE_ENDIAN
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# define SEM_VALUE_OFFSET 0
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# elif __BYTE_ORDER == __BIG_ENDIAN
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# define SEM_VALUE_OFFSET 1
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# else
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# error Unsupported byte order.
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# endif
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# define SEM_NWAITERS_SHIFT 32
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# define SEM_VALUE_MASK (~(unsigned int)0)
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uint64_t data;
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int pshared;
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#define __SEMAPHORE_INITIALIZER(value, pshared) \
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{ (value), (pshared) }
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#else
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# define SEM_VALUE_SHIFT 1
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# define SEM_NWAITERS_MASK ((unsigned int)1)
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unsigned int value;
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unsigned int nwaiters;
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int pshared;
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#define __SEMAPHORE_INITIALIZER(value, pshared) \
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{ (value) << SEM_VALUE_SHIFT, 0, (pshared) }
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#endif
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};
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extern int __sem_waitfast (struct new_sem *isem, int definitive_result);
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#endif /* pt-internal.h */
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