OpenBSD-4.6/lib/libpthread/uthread/uthread_writev.c
/* $OpenBSD: uthread_writev.c,v 1.13 2007/05/18 19:28:50 kurt Exp $ */
/*
* 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: uthread_writev.c,v 1.12 1999/08/28 00:03:55 peter Exp $
*
*/
#include <sys/types.h>
#include <sys/fcntl.h>
#include <sys/uio.h>
#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
ssize_t
writev(int fd, const struct iovec * iov, int iovcnt)
{
struct pthread *curthread = _get_curthread();
int blocking;
int idx = 0;
int type;
ssize_t num = 0;
size_t cnt;
ssize_t n;
ssize_t ret;
struct iovec liov[20];
struct iovec *p_iov = liov;
/* This is a cancellation point: */
_thread_enter_cancellation_point();
/* Check if the array size exceeds to compiled in size: */
if (iovcnt > (int) (sizeof(liov) / sizeof(struct iovec))) {
/* Allocate memory for the local array: */
if ((p_iov = (struct iovec *)
malloc((size_t)iovcnt * sizeof(struct iovec))) == NULL) {
/* Insufficient memory: */
errno = ENOMEM;
_thread_leave_cancellation_point();
return (-1);
}
} else if (iovcnt <= 0) {
errno = EINVAL;
_thread_leave_cancellation_point();
return (-1);
}
/* Copy the caller's array so that it can be modified locally: */
memcpy(p_iov,iov,(size_t)iovcnt * sizeof(struct iovec));
/* Lock the file descriptor for write: */
if ((ret = _FD_LOCK(fd, FD_WRITE, NULL)) == 0) {
/* Get the read/write mode type: */
type = _thread_fd_table[fd]->status_flags->flags & O_ACCMODE;
/* Check if the file is not open for write: */
if (type != O_WRONLY && type != O_RDWR) {
/* File is not open for write: */
errno = EBADF;
_FD_UNLOCK(fd, FD_WRITE);
if (p_iov != liov)
free(p_iov);
_thread_leave_cancellation_point();
return (-1);
}
/* Check if file operations are to block */
blocking = ((_thread_fd_table[fd]->status_flags->flags & O_NONBLOCK) == 0);
/*
* Loop while no error occurs and until the expected number
* of bytes are written if performing a blocking write:
*/
while (ret == 0) {
/* Perform a non-blocking write syscall: */
n = _thread_sys_writev(fd, &p_iov[idx], iovcnt - idx);
/* Check if one or more bytes were written: */
if (n > 0) {
/*
* Keep a count of the number of bytes
* written:
*/
num += n;
/*
* Enter a loop to check if a short write
* occurred and move the index to the
* array entry where the short write
* ended:
*/
cnt = (size_t)n;
while (cnt > 0 && idx < iovcnt) {
/*
* If the residual count exceeds
* the size of this vector, then
* it was completely written:
*/
if (cnt >= p_iov[idx].iov_len)
/*
* Decrement the residual
* count and increment the
* index to the next array
* entry:
*/
cnt -= p_iov[idx++].iov_len;
else {
/*
* This entry was only
* partially written, so
* adjust it's length
* and base pointer ready
* for the next write:
*/
p_iov[idx].iov_len -= cnt;
p_iov[idx].iov_base =
(char *)p_iov[idx].iov_base
+ (ptrdiff_t)cnt;
cnt = 0;
}
}
} else if (n == 0) {
/*
* Avoid an infinite loop if the last iov_len is
* 0.
*/
while (idx < iovcnt && p_iov[idx].iov_len == 0)
idx++;
if (idx == iovcnt) {
ret = num;
break;
}
}
/*
* If performing a blocking write, check if the
* write would have blocked or if some bytes
* were written but there are still more to
* write:
*/
if (blocking && ((n < 0 && (errno == EWOULDBLOCK ||
errno == EAGAIN)) || (n >= 0 && idx < iovcnt))) {
curthread->data.fd.fd = fd;
_thread_kern_set_timeout(NULL);
/* Reset the interrupted operation flag: */
curthread->interrupted = 0;
curthread->closing_fd = 0;
_thread_kern_sched_state(PS_FDW_WAIT,
__FILE__, __LINE__);
/*
* Check if the operation was
* interrupted by a signal
*/
if (curthread->interrupted || curthread->closing_fd) {
if (num > 0) {
/* Return partial success: */
ret = num;
} else {
/* Return an error: */
if (curthread->closing_fd)
errno = EBADF;
else
errno = EINTR;
ret = -1;
}
}
/*
* If performing a non-blocking write,
* just return whatever the write syscall did:
*/
} else if (!blocking) {
/* A non-blocking call might return zero: */
ret = n;
break;
/*
* If there was an error, return partial success
* (if any bytes were written) or else the error:
*/
} else if (n < 0) {
if (num > 0)
ret = num;
else
ret = n;
/* Check if the write has completed: */
} else if (idx == iovcnt)
/* Return the number of bytes written: */
ret = num;
}
_FD_UNLOCK(fd, FD_WRITE);
}
/* If memory was allocated for the array, free it: */
if (p_iov != liov)
free(p_iov);
/* No longer in a cancellation point: */
_thread_leave_cancellation_point();
return (ret);
}
#endif