2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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 AUTHOR 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
32 * $FreeBSD: src/lib/libc_r/uthread/uthread_writev.c,v 1.16.2.6 2002/11/15 18:39:21 archie Exp $
33 * $DragonFly: src/lib/libc_r/uthread/uthread_writev.c,v 1.4 2007/01/08 21:41:53 dillon Exp $
36 #include <sys/types.h>
37 #include <sys/fcntl.h>
44 #include "pthread_private.h"
47 _writev(int fd, const struct iovec * iov, int iovcnt)
49 struct pthread *curthread = _get_curthread();
57 struct iovec liov[20];
58 struct iovec *p_iov = liov;
60 /* Check if the array size exceeds to compiled in size: */
61 if (iovcnt > (sizeof(liov) / sizeof(struct iovec))) {
62 /* Allocate memory for the local array: */
63 if ((p_iov = (struct iovec *)
64 malloc(iovcnt * sizeof(struct iovec))) == NULL) {
65 /* Insufficient memory: */
71 /* Copy the caller's array so that it can be modified locally: */
72 memcpy(p_iov,iov,iovcnt * sizeof(struct iovec));
74 /* Lock the file descriptor for write: */
75 if ((ret = _FD_LOCK(fd, FD_WRITE, NULL)) == 0) {
76 /* Get the read/write mode type: */
77 type = _thread_fd_getflags(fd) & O_ACCMODE;
79 /* Check if the file is not open for write: */
80 if (type != O_WRONLY && type != O_RDWR) {
81 /* File is not open for write: */
83 _FD_UNLOCK(fd, FD_WRITE);
87 /* Check if file operations are to block */
88 blocking = ((_thread_fd_getflags(fd) & O_NONBLOCK) == 0);
91 * Loop while no error occurs and until the expected number
92 * of bytes are written if performing a blocking write:
95 /* Perform a non-blocking write syscall: */
96 n = __sys_extpwritev(fd, &p_iov[idx], iovcnt - idx, O_FNONBLOCKING, -1);
98 /* Check if one or more bytes were written: */
101 * Keep a count of the number of bytes
107 * Enter a loop to check if a short write
108 * occurred and move the index to the
109 * array entry where the short write
113 while (cnt > 0 && idx < iovcnt) {
115 * If the residual count exceeds
116 * the size of this vector, then
117 * it was completely written:
119 if (cnt >= p_iov[idx].iov_len)
121 * Decrement the residual
122 * count and increment the
123 * index to the next array
126 cnt -= p_iov[idx++].iov_len;
129 * This entry was only
130 * partially written, so
132 * and base pointer ready
133 * for the next write:
135 p_iov[idx].iov_len -= cnt;
136 p_iov[idx].iov_base += cnt;
142 * Avoid an infinite loop if the last iov_len is
145 while (idx < iovcnt && p_iov[idx].iov_len == 0)
155 * If performing a blocking write, check if the
156 * write would have blocked or if some bytes
157 * were written but there are still more to
160 if (blocking && ((n < 0 && (errno == EWOULDBLOCK ||
161 errno == EAGAIN)) || (n >= 0 && idx < iovcnt))) {
162 curthread->data.fd.fd = fd;
163 _thread_kern_set_timeout(NULL);
165 /* Reset the interrupted operation flag: */
166 curthread->interrupted = 0;
168 _thread_kern_sched_state(PS_FDW_WAIT,
172 * Check if the operation was
173 * interrupted by a signal
175 if (curthread->interrupted) {
177 /* Return partial success: */
180 /* Return an error: */
187 * If performing a non-blocking write,
188 * just return whatever the write syscall did:
190 } else if (!blocking) {
191 /* A non-blocking call might return zero: */
196 * If there was an error, return partial success
197 * (if any bytes were written) or else the error:
205 /* Check if the write has completed: */
206 } else if (idx == iovcnt)
207 /* Return the number of bytes written: */
210 _FD_UNLOCK(fd, FD_RDWR);
213 /* If memory was allocated for the array, free it: */
221 writev(int fd, const struct iovec *iov, int iovcnt)
225 _thread_enter_cancellation_point();
226 ret = _writev(fd, iov, iovcnt);
227 _thread_leave_cancellation_point();