freebsd-dev/lib/libc_r/uthread/uthread_read.c
deischen f33bb8954f Remove much of the dereferencing of the fd table entries to look
at file flags and replace it with functions that will avoid null
pointer checks.

MFC to be done by archie ;-)

PR:		42100
Reviewed by:	archie, robert
MFC after:	3 days
2002-08-29 23:06:07 +00:00

112 lines
3.3 KiB
C

/*
* 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 AUTHOR 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.
*
* $FreeBSD$
*
*/
#include <sys/types.h>
#include <sys/fcntl.h>
#include <sys/uio.h>
#include <errno.h>
#include <unistd.h>
#include <pthread.h>
#include "pthread_private.h"
__weak_reference(__read, read);
ssize_t
_read(int fd, void *buf, size_t nbytes)
{
struct pthread *curthread = _get_curthread();
int ret;
int type;
/* POSIX says to do just this: */
if (nbytes == 0) {
return (0);
}
/* Lock the file descriptor for read: */
if ((ret = _FD_LOCK(fd, FD_READ, NULL)) == 0) {
/* Get the read/write mode type: */
type = _thread_fd_getflags(fd) & O_ACCMODE;
/* Check if the file is not open for read: */
if (type != O_RDONLY && type != O_RDWR) {
/* File is not open for read: */
errno = EBADF;
_FD_UNLOCK(fd, FD_READ);
return (-1);
}
/* Perform a non-blocking read syscall: */
while ((ret = __sys_read(fd, buf, nbytes)) < 0) {
if ((_thread_fd_getflags(fd) & O_NONBLOCK) == 0 &&
(errno == EWOULDBLOCK || errno == EAGAIN)) {
curthread->data.fd.fd = fd;
_thread_kern_set_timeout(NULL);
/* Reset the interrupted operation flag: */
curthread->interrupted = 0;
_thread_kern_sched_state(PS_FDR_WAIT,
__FILE__, __LINE__);
/*
* Check if the operation was
* interrupted by a signal
*/
if (curthread->interrupted) {
errno = EINTR;
ret = -1;
break;
}
} else {
break;
}
}
_FD_UNLOCK(fd, FD_READ);
}
return (ret);
}
ssize_t
__read(int fd, void *buf, size_t nbytes)
{
ssize_t ret;
_thread_enter_cancellation_point();
ret = _read(fd, buf, nbytes);
_thread_leave_cancellation_point();
return ret;
}