8eb25828ad
that might never be possible if the file was not opened in the corrent mode. This prevents a hang for bad programs. Why do people code like that?
98 lines
3.1 KiB
C
98 lines
3.1 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 REGENTS 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_read.c,v 1.5 1998/06/09 23:20:53 jb Exp $
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*
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*/
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#include <sys/types.h>
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#include <sys/fcntl.h>
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#include <sys/uio.h>
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#include <errno.h>
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#include <unistd.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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ssize_t
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read(int fd, void *buf, size_t nbytes)
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{
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int ret;
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int type;
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/* POSIX says to do just this: */
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if (nbytes == 0)
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return (0);
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/* Lock the file descriptor for read: */
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if ((ret = _FD_LOCK(fd, FD_READ, NULL)) == 0) {
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/* Get the read/write mode type: */
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type = _thread_fd_table[fd]->flags & O_ACCMODE;
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/* Check if the file is not open for read: */
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if (type != O_RDONLY && type != O_RDWR) {
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/* File is not open for read: */
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errno = EBADF;
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_FD_UNLOCK(fd, FD_READ);
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return (-1);
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}
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/* Perform a non-blocking read syscall: */
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while ((ret = _thread_sys_read(fd, buf, nbytes)) < 0) {
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if ((_thread_fd_table[fd]->flags & O_NONBLOCK) == 0 &&
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(errno == EWOULDBLOCK || errno == EAGAIN)) {
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_thread_run->data.fd.fd = fd;
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_thread_kern_set_timeout(NULL);
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/* Reset the interrupted operation flag: */
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_thread_run->interrupted = 0;
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_thread_kern_sched_state(PS_FDR_WAIT,
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__FILE__, __LINE__);
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/*
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* Check if the operation was
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* interrupted by a signal
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*/
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if (_thread_run->interrupted) {
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errno = EINTR;
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ret = -1;
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break;
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}
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} else {
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break;
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}
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}
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_FD_UNLOCK(fd, FD_READ);
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}
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return (ret);
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}
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#endif
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