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 $
35 #include <sys/types.h>
36 #include <sys/fcntl.h>
43 #include "pthread_private.h"
46 _writev(int fd, const struct iovec * iov, int iovcnt)
48 struct pthread *curthread = _get_curthread();
56 struct iovec liov[20];
57 struct iovec *p_iov = liov;
59 /* Check if the array size exceeds to compiled in size: */
60 if (iovcnt > (sizeof(liov) / sizeof(struct iovec))) {
61 /* Allocate memory for the local array: */
62 if ((p_iov = (struct iovec *)
63 malloc(iovcnt * sizeof(struct iovec))) == NULL) {
64 /* Insufficient memory: */
70 /* Copy the caller's array so that it can be modified locally: */
71 memcpy(p_iov,iov,iovcnt * sizeof(struct iovec));
73 /* Lock the file descriptor for write: */
74 if ((ret = _FD_LOCK(fd, FD_WRITE, NULL)) == 0) {
75 /* Get the read/write mode type: */
76 type = _thread_fd_getflags(fd) & O_ACCMODE;
78 /* Check if the file is not open for write: */
79 if (type != O_WRONLY && type != O_RDWR) {
80 /* File is not open for write: */
82 _FD_UNLOCK(fd, FD_WRITE);
86 /* Check if file operations are to block */
87 blocking = ((_thread_fd_getflags(fd) & O_NONBLOCK) == 0);
90 * Loop while no error occurs and until the expected number
91 * of bytes are written if performing a blocking write:
94 /* Perform a non-blocking write syscall: */
95 n = __sys_writev(fd, &p_iov[idx], iovcnt - idx);
97 /* Check if one or more bytes were written: */
100 * Keep a count of the number of bytes
106 * Enter a loop to check if a short write
107 * occurred and move the index to the
108 * array entry where the short write
112 while (cnt > 0 && idx < iovcnt) {
114 * If the residual count exceeds
115 * the size of this vector, then
116 * it was completely written:
118 if (cnt >= p_iov[idx].iov_len)
120 * Decrement the residual
121 * count and increment the
122 * index to the next array
125 cnt -= p_iov[idx++].iov_len;
128 * This entry was only
129 * partially written, so
131 * and base pointer ready
132 * for the next write:
134 p_iov[idx].iov_len -= cnt;
135 p_iov[idx].iov_base += cnt;
141 * Avoid an infinite loop if the last iov_len is
144 while (idx < iovcnt && p_iov[idx].iov_len == 0)
154 * If performing a blocking write, check if the
155 * write would have blocked or if some bytes
156 * were written but there are still more to
159 if (blocking && ((n < 0 && (errno == EWOULDBLOCK ||
160 errno == EAGAIN)) || (n >= 0 && idx < iovcnt))) {
161 curthread->data.fd.fd = fd;
162 _thread_kern_set_timeout(NULL);
164 /* Reset the interrupted operation flag: */
165 curthread->interrupted = 0;
167 _thread_kern_sched_state(PS_FDW_WAIT,
171 * Check if the operation was
172 * interrupted by a signal
174 if (curthread->interrupted) {
176 /* Return partial success: */
179 /* Return an error: */
186 * If performing a non-blocking write,
187 * just return whatever the write syscall did:
189 } else if (!blocking) {
190 /* A non-blocking call might return zero: */
195 * If there was an error, return partial success
196 * (if any bytes were written) or else the error:
204 /* Check if the write has completed: */
205 } else if (idx == iovcnt)
206 /* Return the number of bytes written: */
209 _FD_UNLOCK(fd, FD_RDWR);
212 /* If memory was allocated for the array, free it: */
220 writev(int fd, const struct iovec *iov, int iovcnt)
224 _thread_enter_cancellation_point();
225 ret = _writev(fd, iov, iovcnt);
226 _thread_leave_cancellation_point();