398 lines
11 KiB
C
398 lines
11 KiB
C
/*
|
|
* Copyright (c) 1995 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.
|
|
*
|
|
*/
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <stdlib.h>
|
|
#ifdef _THREAD_SAFE
|
|
#include <pthread.h>
|
|
#include "pthread_private.h"
|
|
|
|
int
|
|
_thread_fd_table_init(int fd)
|
|
{
|
|
int ret = 0;
|
|
int status;
|
|
|
|
/* Block signals: */
|
|
_thread_kern_sig_block(&status);
|
|
|
|
/* Check if the file descriptor is out of range: */
|
|
if (fd < 0 || fd >= _thread_dtablesize)
|
|
/* Return a bad file descriptor error: */
|
|
ret = EBADF;
|
|
|
|
/*
|
|
* 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 ((_thread_fd_table[fd] = (struct fd_table_entry *)
|
|
malloc(sizeof(struct fd_table_entry))) == NULL)
|
|
/* Return a bad file descriptor error: */
|
|
ret = EBADF;
|
|
else {
|
|
/* Assume that the operation will succeed: */
|
|
ret = 0;
|
|
|
|
/* Initialise the file locks: */
|
|
_thread_fd_table[fd]->r_owner = NULL;
|
|
_thread_fd_table[fd]->w_owner = NULL;
|
|
_thread_fd_table[fd]->r_fname = NULL;
|
|
_thread_fd_table[fd]->w_fname = NULL;
|
|
_thread_fd_table[fd]->r_lineno = 0;;
|
|
_thread_fd_table[fd]->w_lineno = 0;;
|
|
_thread_fd_table[fd]->r_lockcount = 0;;
|
|
_thread_fd_table[fd]->w_lockcount = 0;;
|
|
|
|
/* Initialise the read/write queues: */
|
|
_thread_queue_init(&_thread_fd_table[fd]->r_queue);
|
|
_thread_queue_init(&_thread_fd_table[fd]->w_queue);
|
|
|
|
/* Get the flags for the file: */
|
|
if (fd >= 3 && (_thread_fd_table[fd]->flags =
|
|
_thread_sys_fcntl(fd, F_GETFL, 0)) == -1)
|
|
ret = errno;
|
|
|
|
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.
|
|
*/
|
|
_thread_fd_table[fd]->flags =
|
|
_pthread_stdio_flags[fd];
|
|
|
|
/* Make the file descriptor non-blocking: */
|
|
if (_thread_sys_fcntl(fd, F_SETFL,
|
|
_thread_fd_table[fd]->flags | O_NONBLOCK) == -1)
|
|
ret = errno;
|
|
}
|
|
|
|
/* Check if one of the fcntl calls failed: */
|
|
if (ret != 0) {
|
|
/* Free the file descriptor table entry: */
|
|
free(_thread_fd_table[fd]);
|
|
_thread_fd_table[fd] = NULL;
|
|
}
|
|
}
|
|
|
|
/* Unblock signals: */
|
|
_thread_kern_sig_unblock(status);
|
|
|
|
/* Return the completion status: */
|
|
return (ret);
|
|
}
|
|
|
|
void
|
|
_thread_fd_unlock(int fd, int lock_type)
|
|
{
|
|
int ret;
|
|
int status;
|
|
|
|
/* Block signals while the file descriptor lock is tested: */
|
|
_thread_kern_sig_block(&status);
|
|
|
|
/*
|
|
* Check that the file descriptor table is initialised for this
|
|
* entry:
|
|
*/
|
|
if ((ret = _thread_fd_table_init(fd)) != 0) {
|
|
} else {
|
|
/* 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;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Unblock signals again: */
|
|
_thread_kern_sig_unblock(status);
|
|
|
|
/* Nothing to return. */
|
|
return;
|
|
}
|
|
|
|
int
|
|
_thread_fd_lock(int fd, int lock_type, struct timespec * timeout,
|
|
char *fname, int lineno)
|
|
{
|
|
int ret;
|
|
int status;
|
|
|
|
/* Block signals while the file descriptor lock is tested: */
|
|
_thread_kern_sig_block(&status);
|
|
|
|
/*
|
|
* Check that the file descriptor table is initialised for this
|
|
* entry:
|
|
*/
|
|
if ((ret = _thread_fd_table_init(fd)) != 0) {
|
|
} else {
|
|
/* 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);
|
|
|
|
/*
|
|
* 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__);
|
|
|
|
/*
|
|
* Block signals so that the file
|
|
* descriptor lock can again be
|
|
* tested:
|
|
*/
|
|
_thread_kern_sig_block(NULL);
|
|
} 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);
|
|
|
|
/*
|
|
* 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__);
|
|
|
|
/*
|
|
* Block signals so that the file
|
|
* descriptor lock can again be
|
|
* tested:
|
|
*/
|
|
_thread_kern_sig_block(NULL);
|
|
} 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++;
|
|
}
|
|
}
|
|
|
|
/* Unblock signals again: */
|
|
_thread_kern_sig_unblock(status);
|
|
|
|
/* Return the completion status: */
|
|
return (ret);
|
|
}
|
|
#endif
|