thr_writev.c revision 36382 
1/*
2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by John Birrell.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $Id: uthread_writev.c,v 1.5 1998/04/29 09:59:34 jb Exp $
33 *
34 */
35#include <sys/types.h>
36#include <sys/fcntl.h>
37#include <sys/uio.h>
38#include <errno.h>
39#include <unistd.h>
40#ifdef _THREAD_SAFE
41#include <pthread.h>
42#include "pthread_private.h"
43
44ssize_t
45writev(int fd, const struct iovec * iov, int iovcnt)
46{
47	int	blocking;
48	int	status;
49	ssize_t n;
50	ssize_t num = 0;
51	ssize_t	ret;
52	struct iovec liov;
53
54	/* Lock the file descriptor for write: */
55	if ((ret = _thread_fd_lock(fd, FD_WRITE, NULL,
56	    __FILE__, __LINE__)) == 0) {
57		/* Make a local copy of the caller's iov: */
58		liov.iov_base = iov->iov_base;
59		liov.iov_len = iov->iov_len;
60
61		/* Check if file operations are to block */
62		blocking = ((_thread_fd_table[fd]->flags & O_NONBLOCK) == 0);
63
64		/*
65		 * Loop while no error occurs and until the expected number
66		 * of bytes are written if performing a blocking write:
67		 */
68		while (ret == 0) {
69			/* Perform a non-blocking write syscall: */
70			n = _thread_sys_writev(fd, &liov, iovcnt - num);
71
72			/* Check if one or more bytes were written: */
73			if (n > 0) {
74				/* Update the local iov: */
75				liov.iov_base += n;
76				liov.iov_len += n;
77
78				/*
79				 * Keep a count of the number of bytes
80				 * written:
81				 */
82				num += n;
83			}
84
85			/*
86			 * If performing a blocking write, check if the
87			 * write would have blocked or if some bytes
88			 * were written but there are still more to
89			 * write:
90			 */
91			if (blocking && ((n < 0 && (errno == EWOULDBLOCK ||
92			    errno == EAGAIN)) || num < iovcnt)) {
93				_thread_run->data.fd.fd = fd;
94				_thread_kern_set_timeout(NULL);
95
96				/* Reset the interrupted operation flag: */
97				_thread_run->interrupted = 0;
98
99				_thread_kern_sched_state(PS_FDW_WAIT,
100				    __FILE__, __LINE__);
101
102				/*
103				 * Check if the operation was
104				 * interrupted by a signal
105				 */
106				if (_thread_run->interrupted) {
107					/* Return an error: */
108					ret = -1;
109				}
110
111			/*
112			 * If performing a non-blocking write or if an
113			 * error occurred, just return whatever the write
114			 * syscall did:
115			 */
116			} else if (!blocking || n < 0) {
117				/* A non-blocking call might return zero: */
118				ret = n;
119				break;
120
121			/* Check if the write has completed: */
122			} else if (num >= iovcnt)
123				/* Return the number of bytes written: */
124				ret = num;
125		}
126		_thread_fd_unlock(fd, FD_RDWR);
127	}
128	return (ret);
129}
130#endif
131