NetBSD/lib/libpthread/pthreads/fd.c
proven 1c3caff3ff RCS ids added.
pthread_once() moved to separate file.
pthread_detach(), and pthread_join() routines added,
and sleep now sleeps only the running thread not the process.
1994-02-07 22:04:13 +00:00

563 lines
15 KiB
C

/* ==== fd.c ============================================================
* Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu
* 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 Chris Provenzano.
* 4. The name of Chris Provenzano may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``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 CHRIS PROVENZANO 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.
*
* Description : All the syscalls dealing with fds.
*
* 1.00 93/08/14 proven
* -Started coding this file.
*
* 1.01 93/11/13 proven
* -The functions readv() and writev() added.
*/
#ifndef lint
static const char rcsid[] = "$Id: fd.c,v 1.3 1994/02/07 22:04:15 proven Exp $ $provenid: fd.c,v 1.16 1994/02/07 02:18:39 proven Exp $";
#endif
#include <pthread.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <stdarg.h>
#include <fcntl.h>
#include <errno.h>
#include <pthread/posix.h>
/*
* These first functions really should not be called by the user.
*
* I really should dynamically figure out what the table size is.
*/
int dtablesize = 64;
static struct fd_table_entry fd_entry[64];
/* ==========================================================================
* fd_init()
*/
void fd_init(void)
{
int i;
for (i = 0; i < dtablesize; i++) {
fd_table[i] = &fd_entry[i];
fd_table[i]->ops = NULL;
fd_table[i]->type = FD_NT;
fd_table[i]->fd.i = NOTOK;
fd_table[i]->flags = 0;
fd_table[i]->count = 0;
pthread_queue_init(&(fd_table[i]->r_queue));
pthread_queue_init(&(fd_table[i]->w_queue));
fd_table[i]->r_owner = NULL;
fd_table[i]->w_owner = NULL;
fd_table[i]->lock = SEMAPHORE_CLEAR;
fd_table[i]->next = NULL;
fd_table[i]->lockcount = 0;
}
/* Currently only initialize first 3 fds. */
fd_kern_init(0);
fd_kern_init(1);
fd_kern_init(2);
printf ("Warning: threaded process may have changed open file descriptors\n");
}
/* ==========================================================================
* fd_allocate()
*/
int fd_allocate()
{
semaphore *lock;
int i;
for (i = 0; i < dtablesize; i++) {
lock = &(fd_table[i]->lock);
while (SEMAPHORE_TEST_AND_SET(lock)) {
continue;
}
if (fd_table[i]->count || fd_table[i]->r_owner
|| fd_table[i]->w_owner) {
SEMAPHORE_RESET(lock);
continue;
}
if (fd_table[i]->type == FD_NT) {
/* Test to see if the kernel version is in use */
/* If so continue; */
}
fd_table[i]->count++;
SEMAPHORE_RESET(lock);
return(i);
}
pthread_run->error = ENFILE;
return(NOTOK);
}
/* ==========================================================================
* fd_free()
*
* Assumes fd is locked and owner by pthread_run
* Don't clear the queues, fd_unlock will do that.
*/
int fd_free(int fd)
{
struct fd_table_entry *fd_valid;
int ret;
if (ret = --fd_table[fd]->count) {
/* Separate pthread queue into two distinct queues. */
fd_valid = fd_table[fd];
fd_table[fd] = fd_table[fd]->next;
fd_valid->next = fd_table[fd]->next;
}
fd_table[fd]->type = FD_NIU;
fd_table[fd]->fd.i = NOTOK;
fd_table[fd]->next = NULL;
fd_table[fd]->flags = 0;
fd_table[fd]->count = 0;
return(ret);
}
/* ==========================================================================
* fd_basic_unlock()
*
* The real work of unlock without the locking of fd_table[fd].lock.
*/
void fd_basic_unlock(int fd, int lock_type)
{
struct pthread *pthread;
semaphore *plock;
if (fd_table[fd]->r_owner == pthread_run) {
if (pthread = pthread_queue_get(&fd_table[fd]->r_queue)) {
plock = &(pthread->lock);
while (SEMAPHORE_TEST_AND_SET(plock)) {
pthread_yield();
}
pthread_queue_deq(&fd_table[fd]->r_queue);
fd_table[fd]->r_owner = pthread;
pthread->state = PS_RUNNING;
SEMAPHORE_RESET(plock);
} else {
fd_table[fd]->r_owner = NULL;
}
}
if (fd_table[fd]->w_owner == pthread_run) {
if (pthread = pthread_queue_get(&fd_table[fd]->w_queue)) {
plock = &(pthread->lock);
while (SEMAPHORE_TEST_AND_SET(plock)) {
pthread_yield();
}
pthread_queue_deq(&fd_table[fd]->r_queue);
fd_table[fd]->w_owner = pthread;
pthread->state = PS_RUNNING;
SEMAPHORE_RESET(plock);
} else {
fd_table[fd]->w_owner = NULL;
}
}
}
/* ==========================================================================
* fd_unlock()
* If there is a lock count then the function fileunlock will do
* the unlocking, just return.
*/
void fd_unlock(int fd, int lock_type)
{
semaphore *lock;
if (!(fd_table[fd]->lockcount)) {
lock = &(fd_table[fd]->lock);
while (SEMAPHORE_TEST_AND_SET(lock)) {
pthread_yield();
}
fd_basic_unlock(fd, lock_type);
SEMAPHORE_RESET(lock);
}
}
/* ==========================================================================
* fd_basic_lock()
*
* The real work of lock without the locking of fd_table[fd].lock.
* Be sure to leave the lock the same way you found it. i.e. locked.
*/
int fd_basic_lock(unsigned int fd, int lock_type, semaphore * lock)
{
semaphore *plock;
/* If not in use return EBADF error */
if (fd_table[fd]->type == FD_NIU) {
return(NOTOK);
}
/* If not tested, test it and see if it is valid */
if (fd_table[fd]->type == FD_NT) {
/* If not ok return EBADF error */
if (fd_kern_init(fd) != OK) {
return(NOTOK);
}
}
if ((fd_table[fd]->type == FD_HALF_DUPLEX) ||
(lock_type & FD_READ)) {
if (fd_table[fd]->r_owner) {
if (fd_table[fd]->r_owner != pthread_run) {
plock = &(pthread_run->lock);
while (SEMAPHORE_TEST_AND_SET(plock)) {
pthread_yield();
}
pthread_queue_enq(&fd_table[fd]->r_queue, pthread_run);
SEMAPHORE_RESET(lock);
/* Reschedule will unlock pthread_run */
reschedule(PS_FDLR_WAIT);
while(SEMAPHORE_TEST_AND_SET(lock)) {
pthread_yield();
}
} else {
if (!fd_table[fd]->lockcount) {
PANIC();
}
}
}
fd_table[fd]->r_owner = pthread_run;
}
if ((fd_table[fd]->type != FD_HALF_DUPLEX) &&
(lock_type & FD_WRITE)) {
if (fd_table[fd]->w_owner) {
if (fd_table[fd]->w_owner != pthread_run) {
plock = &(pthread_run->lock);
while (SEMAPHORE_TEST_AND_SET(plock)) {
pthread_yield();
}
pthread_queue_enq(&fd_table[fd]->w_queue, pthread_run);
SEMAPHORE_RESET(lock);
/* Reschedule will unlock pthread_run */
reschedule(PS_FDLW_WAIT);
while(SEMAPHORE_TEST_AND_SET(lock)) {
pthread_yield();
}
}
}
fd_table[fd]->w_owner = pthread_run;
}
if (!fd_table[fd]->count) {
fd_basic_unlock(fd, lock_type);
return(NOTOK);
}
return(OK);
}
/* ==========================================================================
* fd_lock()
*/
int fd_lock(unsigned int fd, int lock_type)
{
semaphore *lock;
int error;
if (fd < dtablesize) {
lock = &(fd_table[fd]->lock);
while (SEMAPHORE_TEST_AND_SET(lock)) {
pthread_yield();
}
error = fd_basic_lock(fd, lock_type, lock);
SEMAPHORE_RESET(lock);
return(error);
}
return(NOTOK);
}
/* ==========================================================================
* ======================================================================= */
/* ==========================================================================
* read()
*/
ssize_t read(int fd, void *buf, size_t nbytes)
{
int ret;
if ((ret = fd_lock(fd, FD_READ)) == OK) {
ret = fd_table[fd]->ops->read(fd_table[fd]->fd,
fd_table[fd]->flags, buf, nbytes);
fd_unlock(fd, FD_READ);
}
return(ret);
}
/* ==========================================================================
* readv()
*/
int readv(int fd, const struct iovec *iov, int iovcnt)
{
int ret;
if ((ret = fd_lock(fd, FD_READ)) == OK) {
ret = fd_table[fd]->ops->readv(fd_table[fd]->fd,
fd_table[fd]->flags, iov, iovcnt);
fd_unlock(fd, FD_READ);
}
return(ret);
}
/* ==========================================================================
* write()
*/
ssize_t write(int fd, const void *buf, size_t nbytes)
{
int ret;
if ((ret = fd_lock(fd, FD_WRITE)) == OK) {
ret = fd_table[fd]->ops->write(fd_table[fd]->fd,
fd_table[fd]->flags, buf, nbytes);
fd_unlock(fd, FD_WRITE);
}
return(ret);
}
/* ==========================================================================
* writev()
*/
int writev(int fd, const struct iovec *iov, int iovcnt)
{
int ret;
if ((ret = fd_lock(fd, FD_WRITE)) == OK) {
ret = fd_table[fd]->ops->writev(fd_table[fd]->fd,
fd_table[fd]->flags, iov, iovcnt);
fd_unlock(fd, FD_WRITE);
}
return(ret);
}
/* ==========================================================================
* lseek()
*/
off_t lseek(int fd, off_t offset, int whence)
{
int ret;
if ((ret = fd_lock(fd, FD_RDWR)) == OK) {
ret = fd_table[fd]->ops->seek(fd_table[fd]->fd,
fd_table[fd]->flags, offset, whence);
fd_unlock(fd, FD_RDWR);
}
return(ret);
}
/* ==========================================================================
* close()
*
* The whole close procedure is a bit odd and needs a bit of a rethink.
* For now close() locks the fd, calls fd_free() which checks to see if
* there are any other fd values poinging to the same real fd. If so
* It breaks the wait queue into two sections those that are waiting on fd
* and those waiting on other fd's. Those that are waiting on fd are connected
* to the fd_table[fd] queue, and the count is set to zero, (BUT THE LOCK IS NOT
* RELEASED). close() then calls fd_unlock which give the fd to the next queued
* element which determins that the fd is closed and then calls fd_unlock etc...
*/
int close(int fd)
{
union fd_data realfd;
int ret, flags;
if ((ret = fd_lock(fd, FD_RDWR)) == OK) {
flags = fd_table[fd]->flags;
realfd = fd_table[fd]->fd;
if (fd_free(fd) == OK) {
ret = fd_table[fd]->ops->close(realfd, flags);
}
fd_unlock(fd, FD_RDWR);
}
return(ret);
}
/* ==========================================================================
* fd_basic_dup()
*
* Might need to do more than just what's below.
*/
static inline void fd_basic_dup(int fd, int newfd)
{
fd_table[newfd]->next = fd_table[fd]->next;
fd_table[fd]->next = fd_table[newfd];
fd_table[fd]->count++;
}
/* ==========================================================================
* dup2()
*
* Always lock the lower number fd first to avoid deadlocks.
* newfd must be locked by hand so it can be closed if it is open,
* or it won't be opened while dup is in progress.
*/
int dup2(fd, newfd)
{
union fd_data realfd;
semaphore *lock;
int ret, flags;
if (newfd < dtablesize) {
if (fd < newfd) {
if ((ret = fd_lock(fd, FD_RDWR)) == OK) {
/* Need to lock the newfd by hand */
lock = &(fd_table[newfd]->lock);
while(SEMAPHORE_TEST_AND_SET(lock)) {
pthread_yield();
}
/* Is it inuse */
if (fd_basic_lock(newfd, FD_RDWR, lock) == OK) {
/* free it and check close status */
flags = fd_table[fd]->flags;
realfd = fd_table[fd]->fd;
if (fd_free(fd) == OK) {
ret = fd_table[fd]->ops->close(realfd, flags);
} else {
/* Lots of work to do */
}
}
fd_basic_dup(fd, newfd);
}
fd_unlock(fd, FD_RDWR);
} else {
/* Need to lock the newfd by hand */
lock = &(fd_table[newfd]->lock);
while(SEMAPHORE_TEST_AND_SET(lock)) {
pthread_yield();
}
if ((ret = fd_lock(fd, FD_RDWR)) == OK) {
}
/* Is it inuse */
if ((ret = fd_basic_lock(newfd, FD_RDWR, lock)) == OK) {
/* free it and check close status */
flags = fd_table[fd]->flags;
realfd = fd_table[fd]->fd;
if (fd_free(fd) == OK) {
ret = fd_table[fd]->ops->close(realfd, flags);
} else {
/* Lots of work to do */
}
fd_basic_dup(fd, newfd);
fd_unlock(fd, FD_RDWR);
}
SEMAPHORE_RESET(lock);
}
} else {
ret = NOTOK;
}
return(ret);
}
/* ==========================================================================
* dup()
*/
int dup(int fd)
{
int ret;
if ((ret = fd_lock(fd, FD_RDWR)) == OK) {
ret = fd_allocate();
fd_basic_dup(fd, ret);
fd_unlock(fd, FD_RDWR);
}
return(ret);
}
/* ==========================================================================
* fcntl()
*/
int fcntl(int fd, int cmd, ...)
{
int ret, realfd, flags;
struct flock *flock;
semaphore *plock;
va_list ap;
flags = 0;
if ((ret = fd_lock(fd, FD_RDWR)) == OK) {
va_start(ap, cmd);
switch(cmd) {
case F_DUPFD:
ret = fd_allocate();
fd_basic_dup(va_arg(ap, int), ret);
break;
case F_SETFD:
flags = va_arg(ap, int);
case F_GETFD:
ret = fd_table[fd]->ops->fcntl(fd_table[fd]->fd,
fd_table[fd]->flags, cmd, flags | __FD_NONBLOCK);
break;
case F_GETFL:
ret = fd_table[fd]->flags;
break;
case F_SETFL:
flags = va_arg(ap, int);
if ((ret = fd_table[fd]->ops->fcntl(fd_table[fd]->fd,
fd_table[fd]->flags, cmd, flags | __FD_NONBLOCK)) == OK) {
fd_table[fd]->flags = flags;
}
break;
/* case F_SETLKW: */
/*
* Do the same as SETLK but if it fails with EACCES or EAGAIN
* block the thread and try again later, not implemented yet
*/
/* case F_SETLK: */
/* case F_GETLK:
flock = va_arg(ap, struct flock*);
ret = fd_table[fd]->ops->fcntl(fd_table[fd]->fd,
fd_table[fd]->flags, cmd, flock);
break; */
default:
/* Might want to make va_arg use a union */
ret = fd_table[fd]->ops->fcntl(fd_table[fd]->fd,
fd_table[fd]->flags, cmd, va_arg(ap, void*));
break;
}
va_end(ap);
fd_unlock(fd, FD_RDWR);
}
return(ret);
}