e5a8a007e1
written without returning to the caller. This only occurs on pipes where either the number of bytes written is greater than the pipe buffer or if there is insufficient space in the pipe buffer because the reader is reading slower than the writer is writing.
131 lines
4.0 KiB
C
131 lines
4.0 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_writev.c,v 1.5 1998/04/29 09:59:34 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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writev(int fd, const struct iovec * iov, int iovcnt)
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{
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int blocking;
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int status;
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ssize_t n;
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ssize_t num = 0;
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ssize_t ret;
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struct iovec liov;
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/* Lock the file descriptor for write: */
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if ((ret = _thread_fd_lock(fd, FD_WRITE, NULL,
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__FILE__, __LINE__)) == 0) {
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/* Make a local copy of the caller's iov: */
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liov.iov_base = iov->iov_base;
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liov.iov_len = iov->iov_len;
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/* Check if file operations are to block */
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blocking = ((_thread_fd_table[fd]->flags & O_NONBLOCK) == 0);
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/*
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* Loop while no error occurs and until the expected number
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* of bytes are written if performing a blocking write:
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*/
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while (ret == 0) {
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/* Perform a non-blocking write syscall: */
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n = _thread_sys_writev(fd, &liov, iovcnt - num);
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/* Check if one or more bytes were written: */
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if (n > 0) {
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/* Update the local iov: */
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liov.iov_base += n;
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liov.iov_len += n;
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/*
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* Keep a count of the number of bytes
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* written:
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*/
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num += n;
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}
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/*
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* If performing a blocking write, check if the
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* write would have blocked or if some bytes
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* were written but there are still more to
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* write:
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*/
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if (blocking && ((n < 0 && (errno == EWOULDBLOCK ||
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errno == EAGAIN)) || num < iovcnt)) {
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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_FDW_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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/* Return an error: */
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ret = -1;
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}
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/*
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* If performing a non-blocking write or if an
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* error occurred, just return whatever the write
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* syscall did:
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*/
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} else if (!blocking || n < 0) {
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/* A non-blocking call might return zero: */
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ret = n;
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break;
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/* Check if the write has completed: */
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} else if (num >= iovcnt)
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/* Return the number of bytes written: */
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ret = num;
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}
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_thread_fd_unlock(fd, FD_RDWR);
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}
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return (ret);
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}
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#endif
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