762 lines
20 KiB
C
762 lines
20 KiB
C
/*
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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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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* $Id: uthread_fd.c,v 1.11 1999/06/20 08:28:18 jb Exp $
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*
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#ifdef _THREAD_SAFE
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#include <pthread.h>
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#include "pthread_private.h"
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/* Static variables: */
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static spinlock_t fd_table_lock = _SPINLOCK_INITIALIZER;
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/*
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* This function *must* return -1 and set the thread specific errno
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* as a system call. This is because the error return from this
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* function is propagated directly back from thread-wrapped system
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* calls.
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*/
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int
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_thread_fd_table_init(int fd)
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{
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int ret = 0;
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struct fd_table_entry *entry;
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int saved_errno;
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/* Check if the file descriptor is out of range: */
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if (fd < 0 || fd >= _thread_dtablesize) {
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/* Return a bad file descriptor error: */
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errno = EBADF;
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ret = -1;
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}
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/*
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* Check if memory has already been allocated for this file
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* descriptor:
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*/
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else if (_thread_fd_table[fd] != NULL) {
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/* Memory has already been allocated. */
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/* Allocate memory for the file descriptor table entry: */
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} else if ((entry = (struct fd_table_entry *)
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malloc(sizeof(struct fd_table_entry))) == NULL) {
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/* Return an insufficient memory error: */
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errno = ENOMEM;
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ret = -1;
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} else {
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/* Initialise the file locks: */
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memset(&entry->lock, 0, sizeof(entry->lock));
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entry->r_owner = NULL;
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entry->w_owner = NULL;
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entry->r_fname = NULL;
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entry->w_fname = NULL;
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entry->r_lineno = 0;
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entry->w_lineno = 0;
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entry->r_lockcount = 0;
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entry->w_lockcount = 0;
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/* Initialise the read/write queues: */
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TAILQ_INIT(&entry->r_queue);
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TAILQ_INIT(&entry->w_queue);
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/* Get the flags for the file: */
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if (((fd >= 3) || (_pthread_stdio_flags[fd] == -1)) &&
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(entry->flags = _thread_sys_fcntl(fd, F_GETFL, 0)) == -1) {
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ret = -1;
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}
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else {
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/* Check if a stdio descriptor: */
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if ((fd < 3) && (_pthread_stdio_flags[fd] != -1))
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/*
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* Use the stdio flags read by
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* _pthread_init() to avoid
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* mistaking the non-blocking
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* flag that, when set on one
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* stdio fd, is set on all stdio
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* fds.
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*/
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entry->flags = _pthread_stdio_flags[fd];
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/*
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* Make the file descriptor non-blocking.
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* This might fail if the device driver does
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* not support non-blocking calls, or if the
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* driver is naturally non-blocking.
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*/
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saved_errno = errno;
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_thread_sys_fcntl(fd, F_SETFL,
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entry->flags | O_NONBLOCK);
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errno = saved_errno;
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/* Lock the file descriptor table: */
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_SPINLOCK(&fd_table_lock);
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/*
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* Check if another thread allocated the
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* file descriptor entry while this thread
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* was doing the same thing. The table wasn't
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* kept locked during this operation because
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* it has the potential to recurse.
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*/
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if (_thread_fd_table[fd] == NULL) {
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/* This thread wins: */
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_thread_fd_table[fd] = entry;
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entry = NULL;
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}
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/* Unlock the file descriptor table: */
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_SPINUNLOCK(&fd_table_lock);
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}
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/*
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* Check if another thread initialised the table entry
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* before this one could:
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*/
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if (entry != NULL)
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/*
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* Throw away the table entry that this thread
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* prepared. The other thread wins.
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*/
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free(entry);
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}
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/* Return the completion status: */
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return (ret);
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}
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void
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_thread_fd_unlock(int fd, int lock_type)
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{
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int ret;
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/*
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* Check that the file descriptor table is initialised for this
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* entry:
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*/
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if ((ret = _thread_fd_table_init(fd)) == 0) {
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/*
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* Defer signals to protect the scheduling queues from
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* access by the signal handler:
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*/
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_thread_kern_sig_defer();
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/*
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* Lock the file descriptor table entry to prevent
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* other threads for clashing with the current
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* thread's accesses:
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*/
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_SPINLOCK(&_thread_fd_table[fd]->lock);
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/* Check if the running thread owns the read lock: */
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if (_thread_fd_table[fd]->r_owner == _thread_run) {
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/* Check the file descriptor and lock types: */
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if (lock_type == FD_READ || lock_type == FD_RDWR) {
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/*
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* Decrement the read lock count for the
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* running thread:
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*/
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_thread_fd_table[fd]->r_lockcount--;
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/*
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* Check if the running thread still has read
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* locks on this file descriptor:
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*/
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if (_thread_fd_table[fd]->r_lockcount != 0) {
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}
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/*
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* Get the next thread in the queue for a
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* read lock on this file descriptor:
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*/
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else if ((_thread_fd_table[fd]->r_owner = TAILQ_FIRST(&_thread_fd_table[fd]->r_queue)) == NULL) {
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} else {
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/* Remove this thread from the queue: */
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TAILQ_REMOVE(&_thread_fd_table[fd]->r_queue,
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_thread_fd_table[fd]->r_owner, qe);
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/*
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* Set the state of the new owner of
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* the thread to running:
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*/
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PTHREAD_NEW_STATE(_thread_fd_table[fd]->r_owner,PS_RUNNING);
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/*
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* Reset the number of read locks.
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* This will be incremented by the
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* new owner of the lock when it sees
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* that it has the lock.
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*/
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_thread_fd_table[fd]->r_lockcount = 0;
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}
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}
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}
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/* Check if the running thread owns the write lock: */
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if (_thread_fd_table[fd]->w_owner == _thread_run) {
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/* Check the file descriptor and lock types: */
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if (lock_type == FD_WRITE || lock_type == FD_RDWR) {
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/*
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* Decrement the write lock count for the
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* running thread:
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*/
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_thread_fd_table[fd]->w_lockcount--;
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/*
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* Check if the running thread still has
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* write locks on this file descriptor:
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*/
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if (_thread_fd_table[fd]->w_lockcount != 0) {
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}
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/*
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* Get the next thread in the queue for a
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* write lock on this file descriptor:
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*/
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else if ((_thread_fd_table[fd]->w_owner = TAILQ_FIRST(&_thread_fd_table[fd]->w_queue)) == NULL) {
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} else {
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/* Remove this thread from the queue: */
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TAILQ_REMOVE(&_thread_fd_table[fd]->w_queue,
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_thread_fd_table[fd]->w_owner, qe);
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/*
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* Set the state of the new owner of
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* the thread to running:
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*/
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PTHREAD_NEW_STATE(_thread_fd_table[fd]->w_owner,PS_RUNNING);
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/*
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* Reset the number of write locks.
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* This will be incremented by the
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* new owner of the lock when it
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* sees that it has the lock.
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*/
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_thread_fd_table[fd]->w_lockcount = 0;
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}
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}
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}
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/* Unlock the file descriptor table entry: */
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_SPINUNLOCK(&_thread_fd_table[fd]->lock);
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/*
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* Undefer and handle pending signals, yielding if
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* necessary:
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*/
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_thread_kern_sig_undefer();
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}
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/* Nothing to return. */
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return;
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}
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int
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_thread_fd_lock(int fd, int lock_type, struct timespec * timeout)
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{
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int ret;
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/*
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* Check that the file descriptor table is initialised for this
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* entry:
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*/
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if ((ret = _thread_fd_table_init(fd)) == 0) {
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/*
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* Lock the file descriptor table entry to prevent
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* other threads for clashing with the current
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* thread's accesses:
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*/
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_SPINLOCK(&_thread_fd_table[fd]->lock);
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/* Check the file descriptor and lock types: */
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if (lock_type == FD_READ || lock_type == FD_RDWR) {
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/*
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* Enter a loop to wait for the file descriptor to be
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* locked for read for the current thread:
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*/
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while (_thread_fd_table[fd]->r_owner != _thread_run) {
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/*
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* Check if the file descriptor is locked by
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* another thread:
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*/
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if (_thread_fd_table[fd]->r_owner != NULL) {
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/*
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* Another thread has locked the file
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* descriptor for read, so join the
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* queue of threads waiting for a
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* read lock on this file descriptor:
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*/
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TAILQ_INSERT_TAIL(&_thread_fd_table[fd]->r_queue, _thread_run, qe);
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/*
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* Save the file descriptor details
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* in the thread structure for the
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* running thread:
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*/
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_thread_run->data.fd.fd = fd;
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/* Set the timeout: */
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_thread_kern_set_timeout(timeout);
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/*
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* Unlock the file descriptor
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* table entry:
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*/
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_SPINUNLOCK(&_thread_fd_table[fd]->lock);
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/*
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* Schedule this thread to wait on
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* the read lock. It will only be
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* woken when it becomes the next in
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* the queue and is granted access
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* to the lock by the thread
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* that is unlocking the file
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* descriptor.
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*/
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_thread_kern_sched_state(PS_FDLR_WAIT, __FILE__, __LINE__);
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/*
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* Lock the file descriptor
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* table entry again:
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*/
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_SPINLOCK(&_thread_fd_table[fd]->lock);
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} else {
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/*
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* The running thread now owns the
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* read lock on this file descriptor:
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*/
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_thread_fd_table[fd]->r_owner = _thread_run;
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/*
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* Reset the number of read locks for
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* this file descriptor:
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*/
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_thread_fd_table[fd]->r_lockcount = 0;
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}
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}
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/* Increment the read lock count: */
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_thread_fd_table[fd]->r_lockcount++;
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}
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/* Check the file descriptor and lock types: */
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if (lock_type == FD_WRITE || lock_type == FD_RDWR) {
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/*
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* Enter a loop to wait for the file descriptor to be
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* locked for write for the current thread:
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*/
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while (_thread_fd_table[fd]->w_owner != _thread_run) {
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/*
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* Check if the file descriptor is locked by
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* another thread:
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*/
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if (_thread_fd_table[fd]->w_owner != NULL) {
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/*
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* Another thread has locked the file
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* descriptor for write, so join the
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* queue of threads waiting for a
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* write lock on this file
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* descriptor:
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*/
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TAILQ_INSERT_TAIL(&_thread_fd_table[fd]->w_queue, _thread_run, qe);
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/*
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* Save the file descriptor details
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* in the thread structure for the
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* running thread:
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*/
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_thread_run->data.fd.fd = fd;
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/* Set the timeout: */
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_thread_kern_set_timeout(timeout);
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/*
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* Unlock the file descriptor
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* table entry:
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*/
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_SPINUNLOCK(&_thread_fd_table[fd]->lock);
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/*
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* Schedule this thread to wait on
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* the write lock. It will only be
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* woken when it becomes the next in
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* the queue and is granted access to
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* the lock by the thread that is
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* unlocking the file descriptor.
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*/
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_thread_kern_sched_state(PS_FDLW_WAIT, __FILE__, __LINE__);
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/*
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* Lock the file descriptor
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* table entry again:
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*/
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_SPINLOCK(&_thread_fd_table[fd]->lock);
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} else {
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/*
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* The running thread now owns the
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* write lock on this file
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* descriptor:
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*/
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_thread_fd_table[fd]->w_owner = _thread_run;
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/*
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* Reset the number of write locks
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* for this file descriptor:
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*/
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_thread_fd_table[fd]->w_lockcount = 0;
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}
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}
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/* Increment the write lock count: */
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_thread_fd_table[fd]->w_lockcount++;
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}
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/* Unlock the file descriptor table entry: */
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_SPINUNLOCK(&_thread_fd_table[fd]->lock);
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}
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/* Return the completion status: */
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return (ret);
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}
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void
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_thread_fd_unlock_debug(int fd, int lock_type, char *fname, int lineno)
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{
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int ret;
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/*
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* Check that the file descriptor table is initialised for this
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* entry:
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*/
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if ((ret = _thread_fd_table_init(fd)) == 0) {
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/*
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* Defer signals to protect the scheduling queues from
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* access by the signal handler:
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*/
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_thread_kern_sig_defer();
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/*
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* Lock the file descriptor table entry to prevent
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* other threads for clashing with the current
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* thread's accesses:
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*/
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_spinlock_debug(&_thread_fd_table[fd]->lock, fname, lineno);
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/* Check if the running thread owns the read lock: */
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if (_thread_fd_table[fd]->r_owner == _thread_run) {
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/* Check the file descriptor and lock types: */
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if (lock_type == FD_READ || lock_type == FD_RDWR) {
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/*
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* Decrement the read lock count for the
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* running thread:
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*/
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_thread_fd_table[fd]->r_lockcount--;
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/*
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* Check if the running thread still has read
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* locks on this file descriptor:
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*/
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if (_thread_fd_table[fd]->r_lockcount != 0) {
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}
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/*
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* Get the next thread in the queue for a
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* read lock on this file descriptor:
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*/
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else if ((_thread_fd_table[fd]->r_owner = TAILQ_FIRST(&_thread_fd_table[fd]->r_queue)) == NULL) {
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} else {
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/* Remove this thread from the queue: */
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TAILQ_REMOVE(&_thread_fd_table[fd]->r_queue,
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_thread_fd_table[fd]->r_owner, qe);
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/*
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* Set the state of the new owner of
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* the thread to running:
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*/
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PTHREAD_NEW_STATE(_thread_fd_table[fd]->r_owner,PS_RUNNING);
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/*
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* Reset the number of read locks.
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* This will be incremented by the
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* new owner of the lock when it sees
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* that it has the lock.
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*/
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_thread_fd_table[fd]->r_lockcount = 0;
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}
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}
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}
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/* Check if the running thread owns the write lock: */
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if (_thread_fd_table[fd]->w_owner == _thread_run) {
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/* Check the file descriptor and lock types: */
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if (lock_type == FD_WRITE || lock_type == FD_RDWR) {
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/*
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* Decrement the write lock count for the
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* running thread:
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*/
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_thread_fd_table[fd]->w_lockcount--;
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/*
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* Check if the running thread still has
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* write locks on this file descriptor:
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*/
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if (_thread_fd_table[fd]->w_lockcount != 0) {
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}
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/*
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* Get the next thread in the queue for a
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* write lock on this file descriptor:
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*/
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else if ((_thread_fd_table[fd]->w_owner = TAILQ_FIRST(&_thread_fd_table[fd]->w_queue)) == NULL) {
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} else {
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/* Remove this thread from the queue: */
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TAILQ_REMOVE(&_thread_fd_table[fd]->w_queue,
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_thread_fd_table[fd]->w_owner, qe);
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/*
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* Set the state of the new owner of
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* the thread to running:
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*/
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PTHREAD_NEW_STATE(_thread_fd_table[fd]->w_owner,PS_RUNNING);
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/*
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* Reset the number of write locks.
|
|
* This will be incremented by the
|
|
* new owner of the lock when it
|
|
* sees that it has the lock.
|
|
*/
|
|
_thread_fd_table[fd]->w_lockcount = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Unlock the file descriptor table entry: */
|
|
_SPINUNLOCK(&_thread_fd_table[fd]->lock);
|
|
|
|
/*
|
|
* Undefer and handle pending signals, yielding if
|
|
* necessary.
|
|
*/
|
|
_thread_kern_sig_undefer();
|
|
}
|
|
|
|
/* Nothing to return. */
|
|
return;
|
|
}
|
|
|
|
int
|
|
_thread_fd_lock_debug(int fd, int lock_type, struct timespec * timeout,
|
|
char *fname, int lineno)
|
|
{
|
|
int ret;
|
|
|
|
/*
|
|
* Check that the file descriptor table is initialised for this
|
|
* entry:
|
|
*/
|
|
if ((ret = _thread_fd_table_init(fd)) == 0) {
|
|
/*
|
|
* Lock the file descriptor table entry to prevent
|
|
* other threads for clashing with the current
|
|
* thread's accesses:
|
|
*/
|
|
_spinlock_debug(&_thread_fd_table[fd]->lock, fname, lineno);
|
|
|
|
/* Check the file descriptor and lock types: */
|
|
if (lock_type == FD_READ || lock_type == FD_RDWR) {
|
|
/*
|
|
* Enter a loop to wait for the file descriptor to be
|
|
* locked for read for the current thread:
|
|
*/
|
|
while (_thread_fd_table[fd]->r_owner != _thread_run) {
|
|
/*
|
|
* Check if the file descriptor is locked by
|
|
* another thread:
|
|
*/
|
|
if (_thread_fd_table[fd]->r_owner != NULL) {
|
|
/*
|
|
* Another thread has locked the file
|
|
* descriptor for read, so join the
|
|
* queue of threads waiting for a
|
|
* read lock on this file descriptor:
|
|
*/
|
|
TAILQ_INSERT_TAIL(&_thread_fd_table[fd]->r_queue, _thread_run, qe);
|
|
|
|
/*
|
|
* Save the file descriptor details
|
|
* in the thread structure for the
|
|
* running thread:
|
|
*/
|
|
_thread_run->data.fd.fd = fd;
|
|
_thread_run->data.fd.branch = lineno;
|
|
_thread_run->data.fd.fname = fname;
|
|
|
|
/* Set the timeout: */
|
|
_thread_kern_set_timeout(timeout);
|
|
|
|
/*
|
|
* Unlock the file descriptor
|
|
* table entry:
|
|
*/
|
|
_SPINUNLOCK(&_thread_fd_table[fd]->lock);
|
|
|
|
/*
|
|
* Schedule this thread to wait on
|
|
* the read lock. It will only be
|
|
* woken when it becomes the next in
|
|
* the queue and is granted access
|
|
* to the lock by the thread
|
|
* that is unlocking the file
|
|
* descriptor.
|
|
*/
|
|
_thread_kern_sched_state(PS_FDLR_WAIT, __FILE__, __LINE__);
|
|
|
|
/*
|
|
* Lock the file descriptor
|
|
* table entry again:
|
|
*/
|
|
_SPINLOCK(&_thread_fd_table[fd]->lock);
|
|
|
|
} else {
|
|
/*
|
|
* The running thread now owns the
|
|
* read lock on this file descriptor:
|
|
*/
|
|
_thread_fd_table[fd]->r_owner = _thread_run;
|
|
|
|
/*
|
|
* Reset the number of read locks for
|
|
* this file descriptor:
|
|
*/
|
|
_thread_fd_table[fd]->r_lockcount = 0;
|
|
|
|
/*
|
|
* Save the source file details for
|
|
* debugging:
|
|
*/
|
|
_thread_fd_table[fd]->r_fname = fname;
|
|
_thread_fd_table[fd]->r_lineno = lineno;
|
|
}
|
|
}
|
|
|
|
/* Increment the read lock count: */
|
|
_thread_fd_table[fd]->r_lockcount++;
|
|
}
|
|
|
|
/* Check the file descriptor and lock types: */
|
|
if (lock_type == FD_WRITE || lock_type == FD_RDWR) {
|
|
/*
|
|
* Enter a loop to wait for the file descriptor to be
|
|
* locked for write for the current thread:
|
|
*/
|
|
while (_thread_fd_table[fd]->w_owner != _thread_run) {
|
|
/*
|
|
* Check if the file descriptor is locked by
|
|
* another thread:
|
|
*/
|
|
if (_thread_fd_table[fd]->w_owner != NULL) {
|
|
/*
|
|
* Another thread has locked the file
|
|
* descriptor for write, so join the
|
|
* queue of threads waiting for a
|
|
* write lock on this file
|
|
* descriptor:
|
|
*/
|
|
TAILQ_INSERT_TAIL(&_thread_fd_table[fd]->w_queue, _thread_run, qe);
|
|
|
|
/*
|
|
* Save the file descriptor details
|
|
* in the thread structure for the
|
|
* running thread:
|
|
*/
|
|
_thread_run->data.fd.fd = fd;
|
|
_thread_run->data.fd.branch = lineno;
|
|
_thread_run->data.fd.fname = fname;
|
|
|
|
/* Set the timeout: */
|
|
_thread_kern_set_timeout(timeout);
|
|
|
|
/*
|
|
* Unlock the file descriptor
|
|
* table entry:
|
|
*/
|
|
_SPINUNLOCK(&_thread_fd_table[fd]->lock);
|
|
|
|
/*
|
|
* Schedule this thread to wait on
|
|
* the write lock. It will only be
|
|
* woken when it becomes the next in
|
|
* the queue and is granted access to
|
|
* the lock by the thread that is
|
|
* unlocking the file descriptor.
|
|
*/
|
|
_thread_kern_sched_state(PS_FDLW_WAIT, __FILE__, __LINE__);
|
|
|
|
/*
|
|
* Lock the file descriptor
|
|
* table entry again:
|
|
*/
|
|
_SPINLOCK(&_thread_fd_table[fd]->lock);
|
|
} else {
|
|
/*
|
|
* The running thread now owns the
|
|
* write lock on this file
|
|
* descriptor:
|
|
*/
|
|
_thread_fd_table[fd]->w_owner = _thread_run;
|
|
|
|
/*
|
|
* Reset the number of write locks
|
|
* for this file descriptor:
|
|
*/
|
|
_thread_fd_table[fd]->w_lockcount = 0;
|
|
|
|
/*
|
|
* Save the source file details for
|
|
* debugging:
|
|
*/
|
|
_thread_fd_table[fd]->w_fname = fname;
|
|
_thread_fd_table[fd]->w_lineno = lineno;
|
|
}
|
|
}
|
|
|
|
/* Increment the write lock count: */
|
|
_thread_fd_table[fd]->w_lockcount++;
|
|
}
|
|
|
|
/* Unlock the file descriptor table entry: */
|
|
_SPINUNLOCK(&_thread_fd_table[fd]->lock);
|
|
}
|
|
|
|
/* Return the completion status: */
|
|
return (ret);
|
|
}
|
|
#endif
|