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freebsd_amp_hwpstate/lib/libc_r/uthread/uthread_fd.c

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/*
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: uthread_fd.c,v 1.8 1998/06/09 23:16:53 jb Exp $
*
*/
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
/* Static variables: */
static spinlock_t fd_table_lock = _SPINLOCK_INITIALIZER;
/*
* This function *must* return -1 and set the thread specific errno
* as a system call. This is because the error return from this
* function is propagated directly back from thread-wrapped system
* calls.
*/
int
_thread_fd_table_init(int fd)
{
int ret = 0;
struct fd_table_entry *entry;
int saved_errno;
/* Check if the file descriptor is out of range: */
if (fd < 0 || fd >= _thread_dtablesize) {
/* Return a bad file descriptor error: */
errno = EBADF;
ret = -1;
}
/*
* Check if memory has already been allocated for this file
* descriptor:
*/
else if (_thread_fd_table[fd] != NULL) {
/* Memory has already been allocated. */
/* Allocate memory for the file descriptor table entry: */
} else if ((entry = (struct fd_table_entry *)
malloc(sizeof(struct fd_table_entry))) == NULL) {
/* Return an insufficient memory error: */
errno = ENOMEM;
ret = -1;
} else {
/* Initialise the file locks: */
memset(&entry->lock, 0, sizeof(entry->lock));
entry->r_owner = NULL;
entry->w_owner = NULL;
entry->r_fname = NULL;
entry->w_fname = NULL;
entry->r_lineno = 0;;
entry->w_lineno = 0;;
entry->r_lockcount = 0;;
entry->w_lockcount = 0;;
/* Initialise the read/write queues: */
_thread_queue_init(&entry->r_queue);
_thread_queue_init(&entry->w_queue);
/* Get the flags for the file: */
if (fd >= 3 && (entry->flags =
_thread_sys_fcntl(fd, F_GETFL, 0)) == -1) {
ret = -1;
}
else {
/* Check if a stdio descriptor: */
if (fd < 3)
/*
* Use the stdio flags read by
* _pthread_init() to avoid
* mistaking the non-blocking
* flag that, when set on one
* stdio fd, is set on all stdio
* fds.
*/
entry->flags = _pthread_stdio_flags[fd];
/*
* Make the file descriptor non-blocking.
* This might fail if the device driver does
* not support non-blocking calls, or if the
* driver is naturally non-blocking.
*/
saved_errno = errno;
_thread_sys_fcntl(fd, F_SETFL,
entry->flags | O_NONBLOCK);
errno = saved_errno;
/* Lock the file descriptor table: */
_SPINLOCK(&fd_table_lock);
/*
* Check if another thread allocated the
* file descriptor entry while this thread
* was doing the same thing. The table wasn't
* kept locked during this operation because
* it has the potential to recurse.
*/
if (_thread_fd_table[fd] == NULL) {
/* This thread wins: */
_thread_fd_table[fd] = entry;
entry = NULL;
}
/* Unlock the file descriptor table: */
_SPINUNLOCK(&fd_table_lock);
}
/*
* Check if another thread initialised the table entry
* before this one could:
*/
if (entry != NULL)
/*
* Throw away the table entry that this thread
* prepared. The other thread wins.
*/
free(entry);
}
/* Return the completion status: */
return (ret);
}
void
_thread_fd_unlock(int fd, int lock_type)
{
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(&_thread_fd_table[fd]->lock);
/* Check if the running thread owns the read lock: */
if (_thread_fd_table[fd]->r_owner == _thread_run) {
/* Check the file descriptor and lock types: */
if (lock_type == FD_READ || lock_type == FD_RDWR) {
/*
* Decrement the read lock count for the
* running thread:
*/
_thread_fd_table[fd]->r_lockcount--;
/*
* Check if the running thread still has read
* locks on this file descriptor:
*/
if (_thread_fd_table[fd]->r_lockcount != 0) {
}
/*
* Get the next thread in the queue for a
* read lock on this file descriptor:
*/
else if ((_thread_fd_table[fd]->r_owner = _thread_queue_deq(&_thread_fd_table[fd]->r_queue)) == NULL) {
} else {
/*
* Set the state of the new owner of
* the thread to running:
*/
PTHREAD_NEW_STATE(_thread_fd_table[fd]->r_owner,PS_RUNNING);
/*
* Reset the number of read locks.
* This will be incremented by the
* new owner of the lock when it sees
* that it has the lock.
*/
_thread_fd_table[fd]->r_lockcount = 0;
}
}
}
/* Check if the running thread owns the write lock: */
if (_thread_fd_table[fd]->w_owner == _thread_run) {
/* Check the file descriptor and lock types: */
if (lock_type == FD_WRITE || lock_type == FD_RDWR) {
/*
* Decrement the write lock count for the
* running thread:
*/
_thread_fd_table[fd]->w_lockcount--;
/*
* Check if the running thread still has
* write locks on this file descriptor:
*/
if (_thread_fd_table[fd]->w_lockcount != 0) {
}
/*
* Get the next thread in the queue for a
* write lock on this file descriptor:
*/
else if ((_thread_fd_table[fd]->w_owner = _thread_queue_deq(&_thread_fd_table[fd]->w_queue)) == NULL) {
} else {
/*
* Set the state of the new owner of
* the thread to running:
*/
PTHREAD_NEW_STATE(_thread_fd_table[fd]->w_owner,PS_RUNNING);
/*
* 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);
}
/* Nothing to return. */
return;
}
int
_thread_fd_lock(int fd, int lock_type, struct timespec * timeout)
{
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(&_thread_fd_table[fd]->lock);
/* 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:
*/
_thread_queue_enq(&_thread_fd_table[fd]->r_queue, _thread_run);
/*
* Save the file descriptor details
* in the thread structure for the
* running thread:
*/
_thread_run->data.fd.fd = fd;
/* 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;
}
}
/* 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:
*/
_thread_queue_enq(&_thread_fd_table[fd]->w_queue, _thread_run);
/*
* Save the file descriptor details
* in the thread structure for the
* running thread:
*/
_thread_run->data.fd.fd = fd;
/* 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;
}
}
/* 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);
}
void
_thread_fd_unlock_debug(int fd, int lock_type, 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 if the running thread owns the read lock: */
if (_thread_fd_table[fd]->r_owner == _thread_run) {
/* Check the file descriptor and lock types: */
if (lock_type == FD_READ || lock_type == FD_RDWR) {
/*
* Decrement the read lock count for the
* running thread:
*/
_thread_fd_table[fd]->r_lockcount--;
/*
* Check if the running thread still has read
* locks on this file descriptor:
*/
if (_thread_fd_table[fd]->r_lockcount != 0) {
}
/*
* Get the next thread in the queue for a
* read lock on this file descriptor:
*/
else if ((_thread_fd_table[fd]->r_owner = _thread_queue_deq(&_thread_fd_table[fd]->r_queue)) == NULL) {
} else {
/*
* Set the state of the new owner of
* the thread to running:
*/
PTHREAD_NEW_STATE(_thread_fd_table[fd]->r_owner,PS_RUNNING);
/*
* Reset the number of read locks.
* This will be incremented by the
* new owner of the lock when it sees
* that it has the lock.
*/
_thread_fd_table[fd]->r_lockcount = 0;
}
}
}
/* Check if the running thread owns the write lock: */
if (_thread_fd_table[fd]->w_owner == _thread_run) {
/* Check the file descriptor and lock types: */
if (lock_type == FD_WRITE || lock_type == FD_RDWR) {
/*
* Decrement the write lock count for the
* running thread:
*/
_thread_fd_table[fd]->w_lockcount--;
/*
* Check if the running thread still has
* write locks on this file descriptor:
*/
if (_thread_fd_table[fd]->w_lockcount != 0) {
}
/*
* Get the next thread in the queue for a
* write lock on this file descriptor:
*/
else if ((_thread_fd_table[fd]->w_owner = _thread_queue_deq(&_thread_fd_table[fd]->w_queue)) == NULL) {
} else {
/*
* Set the state of the new owner of
* the thread to running:
*/
PTHREAD_NEW_STATE(_thread_fd_table[fd]->w_owner,PS_RUNNING);
/*
* 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);
}
/* 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:
*/
_thread_queue_enq(&_thread_fd_table[fd]->r_queue, _thread_run);
/*
* 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:
*/
_thread_queue_enq(&_thread_fd_table[fd]->w_queue, _thread_run);
/*
* 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
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