mirror of
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5afdca0087
1998-03-11 00:42 Wolfram Gloger <wmglo@dent.med.uni-muenchen.de> * linuxthreads/manager.c: Enable resetting of the thread scheduling policy to SCHED_OTHER when the parent thread has a different one. 1998-02-01 13:51 Ulrich Drepper <drepper@cygnus.com> * sysdeps/unix/sysv/linux/bits/posix_opt.h: Define _POSIX_ASYNCHRONOUS_IO. * sysdeps/pthread/pthread.h: Define bits for Unix98 variants of mutexes. * mutex.c: Implement new mutex types. * internals.h: Include <signal.h>. * libpthread.map: Add __erno_location and __h_errno_location. * errno.c: Return pointer to variable actually in use. This might not be the one in the thread structure. * internals.h (struct _pthread_descr_struct): Add new fields p_errnop and p_h_errnop. * manager.c (__pthread_manager): Set p_errnop and p_h_errnop member of manager thread structure. (pthread_handle_create): Set p_errnop and p_h_errnop members for new thread. * pthread.c: Adapt initializer for thread structures. (__pthread_initial_thread): Set p_errnop and p_h_errnop member. (__pthread_reset_main_thread): Reset p_errnop and p_h_errnop of current thread to global variables. 1998-01-31 17:27 Ulrich Drepper <drepper@cygnus.com> * rwlock.c: New file. * Makefile (libpthread-routines): Add rwlock. * sysdeps/pthread/pthread.h: Define data structures and declare functions. * libpthread.map: Add new functions. 1997-12-18 13:50 Philip Blundell <pb@nexus.co.uk> * sysdeps/arm/pt-machine.h: New file; add ARM support. * sysdeps/arm/Implies: likewise. * README: Document it. 1997-12-13 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * signals.c: Remove unneeded initializer for sigwaited, saving a 1997-04-11 01:18 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * semaphore.c (sem_init): Set sem_spinlock only if available. 1997-12-04 01:48 Ulrich Drepper <drepper@cygnus.com> * mutex.c: Implement PTHREAD_MUTEX_CHECKERROR. * sysdeps/pthread/pthread.h: Define PTHREAD_MUTEX_CHECKERROR. * Makefile: Update from LinuxThreads 0.7. * internals.h. Likewise. * manager.c: Likewise. * mutex.c: Likewise. * pthread.c: Likewise. * signals.c: Likewise. * specific.c: Likewise. * Examples/ex3.c: Likewise. 1997-11-20 18:13 Ulrich Drepper <drepper@cygnus.com> * pthread.c (__pthread_reset_main_thread): Close pipe only if still open. 1997-10-29 05:38 Ulrich Drepper <drepper@cygnus.com> * wrapsyscall.c: Add socket functions which are also cancelation points. 1997-10-19 21:40 Wolfram Gloger <wg@wolfram.dent.med.uni-muenchen.de> * specific.c (__libc_internal_tsd_set, __libc_internal_tsd_get): New functions for fast thread specific data within libc. * internals.h: Add new array p_libc_specific to struct _pthread_descr_struct. * sysdeps/pthread/bits/libc-lock.h: Declare new functions. 1997-10-13 05:39 Ulrich Drepper <drepper@cygnus.com> * semaphore.h: Add __BEGIN_DECLS/__END_DECLS. Reported by Ralf Corsepius <corsepiu@faw.uni-ulm.de>. 1997-08-29 03:05 Ulrich Drepper <drepper@cygnus.com> * internals.h (struct _pthread_descr_struct): Add definitions for two-level specific key handling. * manager.c (pthread_handle_create): Initialize specific memory array. * specific.c: Implement two-level key handling. * weaks.c: Don't provide dummy key handling. * sysdeps/pthread/bits/libc-lock.h: Typedef __libc_lock_t (no #define). Add definition of __libc_key_t. * sysdeps/unix/sysv/linux/bits/local_lim.h: Define PTHREAD_KEYS_MAX as 1024. Add definition of _POSIX_THREAD_DESTRUCTOR_ITERATIONS and PTHREAD_DESTRUCTOR_ITERATIONS. * manager.c (pthread_handle_create): Compare mmap result with MAP_FAILED. * ptfork.c: Rename to __pthread_atfork and make old name a weak alias. * sysdeps/pthread/bits/pthread.h: Add prototype for __pthread_atfork. 1997-08-22 19:04 Richard Henderson <rth@cygnus.com> sysdeps/sparc -> sysdeps/sparc/sparc32 sysdeps/sparc64 -> sysdeps/sparc/sparc64 * internals.h: Change definition of THREAD_SELF to be an expression, not a statement that did a return. * sysdeps/alpha/pt-machine.h (THREAD_SELF): Update accordingly. * sysdeps/sparc/sparc32/pt-machine.h (THREAD_SELF, INIT_THREAD_SELF): Follow Solaris and use a "system reserved" register (%g6) to hold the thread descriptor. * sysdeps/sparc/sparc64/pt-machine.h: Likewise. 1997-08-03 00:09 Ulrich Drepper <drepper@cygnus.com> * mutex.c: Correct pthread_once. Patch by Xavier Leroy. * sysdeps/pthread/pthread.h: Add prototype for __pthread_once. * sysdeps/pthread/bits/pthread.h: Add macros for __libc_once. * semaphore.c: Include spinlock.h only when needed. * specific.c (__pthread_setsepcific, __pthread_getspecific): Reject keys for entries not in use. * weaks.c: Implement key handling functions for real. 1997-06-29 01:04 Richard Henderson <richard@gnu.ai.mit.edu> Initial sparc64-linux support: * linuxthreads/sysdeps/sparc64/Implies: New file. * linuxthreads/sysdeps/sparc64/pt-machine.h: Likewise. 1997-06-29 00:48 Ulrich Drepper <drepper@cygnus.com> * semaphore.c: Include spinlock.h at correct place. Patch by HJ Lu. 1997-06-13 10:06 Richard Henderson <rth@tamu.edu> The Great Bit File Move: * sysdeps/alpha/semaphorebits.h: -> .../bits/semaphore.h. * sysdeps/powerpc/semaphorebits.h: Likewise. * sysdeps/pthread/cmpxchg/semaphorebits.h: Likewise. * sysdeps/pthread/no-cmpxchg/semaphorebits.h: Likewise. * sysdeps/pthread/libc-lock.h: -> bits/ * sysdeps/pthread/stdio-lock.h: Likewise. * sysdeps/unix/sysv/linux/local_lim.h: Likewise. * sysdeps/unix/sysv/linux/posix_opt.h: Likewise. * semaphore.h: Likewise. * sysdeps/pthread/pthread.h: Likewise. * lockfile.c: <foo.h> -> <bits/foo.h>. * semaphore.h: Likewise. * Makefile: (headers): foo.h -> bits/foo.h. * sysdeps/pthread/Makefile: Likewise. 1997-04-11 01:18 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * semaphore.c (sem_init): Set sem_spinlock only if available. * sysdeps/m68k/pt-machine.h (testandset, __compare_and_swap): Fix asm constraints. 1997-04-09 03:00 Ulrich Drepper <drepper@cygnus.com> Update from LinuxThreads 0.6. * attr.c (pthread_attr_getdetachstate): Use __sched_get_priority_max and __sched_get_priority_min instead of names without `__'. * manager.c: Rewrite large parts to implement opaque pthread_t. * cancel.c: Adapt for opaque pthread_t type. * condvar.c: Likewise. * errno.c: Likewise. * join.c: Likewise. * mutex.c: Likewise. * pthread.c: Likewise. * signals.c: Likewise. * specific.c: Likewise. * restart.h: Likewise. * queue.h: Likewise. * Examples/ex3.c: Likewise. * Examples/ex4.c: Likewise. * sysdeps/pthread/pthread.h: Likewise. * pthread.c: Accumulate time for all threads in thread manager. * semaphore.c: Implement fallback implementation for architectures sometimes missing compare-exchange operations. * cancel.c (pthread_cancel): Validate handle argument. * join.c (pthread_join): Likewise. (pthread_detach): Likewise. * signals.c (pthread_kill): Likewise. * spinlock.h (acquire): Use __sched_yield not sched_yield. * queue.h (enqueue): Enqueue thread according to priority. * internals.c (struct pthread_start_args): New struct for passing args to cloning function. (struct _pthread): Rename to _pthread_descr_struct and adapt for opaque pthread_t. * Examples/Makefile (clean): Pass -f option to rm. * sysdeps/i386/pt-machine.h: Add check for compare-exchange instruction and define TEST_FOR_COMPARE_AND_SWAP. * sysdeps/i386/i486/pt-machine.h: Removed. * sysdeps/unix/sysv/linux/local_lim.h (PTHREAD_THREADS_MAX): Increase to 1024. 1997-04-04 16:38 Ulrich Drepper <drepper@cygnus.com> * restart.h (suspend): Clear p_signal before suspending. (suspend_with_cancellation): Likewise. Patch by Xavier Leroy <Xavier.Leroy@inria.fr>. * weaks.c: Make __pthread_key_create return 1. * sysdeps/pthread/libc-lock.h: Define __libc_key_create, __libc_getspecific, __libc_setspecific, and __libc_key_t. * sysdeps/pthread/stdio-lock.h: Don't care for implementation not using libio. 1997-03-19 15:13 Miguel de Icaza <miguel@nuclecu.unam.mx> * sysdeps/sparc/pt-machine (RELEASE): Fix. 1997-03-01 07:55 Geoff Keating <geoffk@ozemail.com.au> * sysdeps/powerpc/Implies: Added. * sysdeps/powerpc/pt-machine.h: Added. * sysdeps/powerpc/semaphorebits.h: Added. 1997-01-22 01:22 Ulrich Drepper <drepper@cygnus.com> * linuxtheads/pthread.c (__pthread_initial_thread): Correct initializer. (__pthread_manager_thread): Likewise. Reported by Andreas Jaeger. 1997-01-18 22:15 Richard Henderson <rth@tamu.edu> Since sigset_t no longer fits in a register, we can't pass in the thread's initial mask so easily. Take this opportunity to simplify the clone implementation by only accepting a single void* argument. * linuxthreads/manager.c (__pthread_manager): Put thread vitals in the thread struct instead of as arguments through clone. (pthread_start_thread): Look for them there. * linuxthreads/internals.h (struct _pthread): Add p_initial_fn, p_initial_fn_arg, p_initial_mask. Fix __pthread_manager proto. * linuxthreads/pthread.c (pthread_initialize_manager): Revise clone invocation.
237 lines
6.6 KiB
C
237 lines
6.6 KiB
C
/* Linuxthreads - a simple clone()-based implementation of Posix */
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/* threads for Linux. */
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/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
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/* */
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/* This program is free software; you can redistribute it and/or */
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/* modify it under the terms of the GNU Library General Public License */
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/* as published by the Free Software Foundation; either version 2 */
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/* of the License, or (at your option) any later version. */
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/* */
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/* This program 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 */
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/* GNU Library General Public License for more details. */
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/* Semaphores a la POSIX 1003.1b */
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#include "pthread.h"
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#include "semaphore.h"
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#include "internals.h"
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#include "restart.h"
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#if !defined HAS_COMPARE_AND_SWAP && !defined TEST_FOR_COMPARE_AND_SWAP
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/* If we have no atomic compare and swap, fake it using an extra spinlock. */
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#include "spinlock.h"
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static inline int sem_compare_and_swap(sem_t *sem, long oldval, long newval)
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{
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int ret;
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acquire(&sem->sem_spinlock);
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ret = (sem->sem_status == oldval);
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if (ret) sem->sem_status = newval;
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release(&sem->sem_spinlock);
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return ret;
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}
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#elif defined TEST_FOR_COMPARE_AND_SWAP
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#include "spinlock.h"
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static int has_compare_and_swap = -1; /* to be determined at run-time */
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static inline int sem_compare_and_swap(sem_t *sem, long oldval, long newval)
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{
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int ret;
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if (has_compare_and_swap == 1)
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return __compare_and_swap(&sem->sem_status, oldval, newval);
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acquire(&sem->sem_spinlock);
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ret = (sem->sem_status == oldval);
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if (ret) sem->sem_status = newval;
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release(&sem->sem_spinlock);
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return ret;
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}
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#else
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/* But if we do have an atomic compare and swap, use it! */
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static inline int sem_compare_and_swap(sem_t *sem, long oldval, long newval)
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{
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return __compare_and_swap(&sem->sem_status, oldval, newval);
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}
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#endif
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/* The state of a semaphore is represented by a long int encoding
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either the semaphore count if >= 0 and no thread is waiting on it,
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or the head of the list of threads waiting for the semaphore.
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To distinguish the two cases, we encode the semaphore count N
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as 2N+1, so that it has the lowest bit set.
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A sequence of sem_wait operations on a semaphore initialized to N
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result in the following successive states:
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2N+1, 2N-1, ..., 3, 1, &first_waiting_thread, &second_waiting_thread, ...
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*/
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static void sem_restart_list(pthread_descr waiting);
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int sem_init(sem_t *sem, int pshared, unsigned int value)
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{
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if ((long)value > SEM_VALUE_MAX) {
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errno = EINVAL;
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return -1;
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}
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if (pshared) {
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errno = ENOSYS;
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return -1;
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}
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#ifdef TEST_FOR_COMPARE_AND_SWAP
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if (has_compare_and_swap == -1) {
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has_compare_and_swap = compare_and_swap_is_available();
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}
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#endif
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#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP
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sem->sem_spinlock = 0;
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#endif
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sem->sem_status = ((long)value << 1) + 1;
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return 0;
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}
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int sem_wait(sem_t * sem)
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{
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long oldstatus, newstatus;
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volatile pthread_descr self = thread_self();
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pthread_descr * th;
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while (1) {
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do {
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oldstatus = sem->sem_status;
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if ((oldstatus & 1) && (oldstatus != 1))
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newstatus = oldstatus - 2;
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else {
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newstatus = (long) self;
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self->p_nextwaiting = (pthread_descr) oldstatus;
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}
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}
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while (! sem_compare_and_swap(sem, oldstatus, newstatus));
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if (newstatus & 1)
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/* We got the semaphore. */
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return 0;
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/* Wait for sem_post or cancellation */
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suspend_with_cancellation(self);
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/* This is a cancellation point */
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if (self->p_canceled && self->p_cancelstate == PTHREAD_CANCEL_ENABLE) {
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/* Remove ourselves from the waiting list if we're still on it */
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/* First check if we're at the head of the list. */
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do {
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oldstatus = sem->sem_status;
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if (oldstatus != (long) self) break;
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newstatus = (long) self->p_nextwaiting;
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}
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while (! sem_compare_and_swap(sem, oldstatus, newstatus));
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/* Now, check if we're somewhere in the list.
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There's a race condition with sem_post here, but it does not matter:
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the net result is that at the time pthread_exit is called,
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self is no longer reachable from sem->sem_status. */
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if (oldstatus != (long) self && (oldstatus & 1) == 0) {
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for (th = &(((pthread_descr) oldstatus)->p_nextwaiting);
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*th != NULL && *th != (pthread_descr) 1;
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th = &((*th)->p_nextwaiting)) {
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if (*th == self) {
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*th = self->p_nextwaiting;
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break;
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}
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}
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}
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pthread_exit(PTHREAD_CANCELED);
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}
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}
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}
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int sem_trywait(sem_t * sem)
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{
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long oldstatus, newstatus;
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do {
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oldstatus = sem->sem_status;
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if ((oldstatus & 1) == 0 || (oldstatus == 1)) {
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errno = EAGAIN;
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return -1;
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}
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newstatus = oldstatus - 2;
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}
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while (! sem_compare_and_swap(sem, oldstatus, newstatus));
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return 0;
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}
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int sem_post(sem_t * sem)
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{
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long oldstatus, newstatus;
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do {
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oldstatus = sem->sem_status;
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if ((oldstatus & 1) == 0)
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newstatus = 3;
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else {
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if (oldstatus >= SEM_VALUE_MAX) {
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/* Overflow */
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errno = ERANGE;
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return -1;
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}
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newstatus = oldstatus + 2;
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}
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}
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while (! sem_compare_and_swap(sem, oldstatus, newstatus));
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if ((oldstatus & 1) == 0)
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sem_restart_list((pthread_descr) oldstatus);
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return 0;
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}
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int sem_getvalue(sem_t * sem, int * sval)
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{
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long status = sem->sem_status;
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if (status & 1)
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*sval = (int)((unsigned long) status >> 1);
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else
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*sval = 0;
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return 0;
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}
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int sem_destroy(sem_t * sem)
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{
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if ((sem->sem_status & 1) == 0) {
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errno = EBUSY;
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return -1;
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}
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return 0;
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}
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/* Auxiliary function for restarting all threads on a waiting list,
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in priority order. */
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static void sem_restart_list(pthread_descr waiting)
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{
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pthread_descr th, towake, *p;
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/* Sort list of waiting threads by decreasing priority (insertion sort) */
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towake = NULL;
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while (waiting != (pthread_descr) 1) {
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th = waiting;
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waiting = waiting->p_nextwaiting;
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p = &towake;
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while (*p != NULL && th->p_priority < (*p)->p_priority)
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p = &((*p)->p_nextwaiting);
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th->p_nextwaiting = *p;
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*p = th;
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}
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/* Wake up threads in priority order */
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while (towake != NULL) {
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th = towake;
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towake = towake->p_nextwaiting;
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th->p_nextwaiting = NULL;
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restart(th);
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}
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}
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