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. Neither the name of the author nor the names of any co-contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/types.h>
33 #include <sys/fcntl.h>
40 #include "pthread_private.h"
42 __weak_reference(__writev, writev);
45 _writev(int fd, const struct iovec * iov, int iovcnt)
47 struct pthread *curthread = _get_curthread();
55 struct iovec liov[20];
56 struct iovec *p_iov = liov;
58 /* Check if the array size exceeds to compiled in size: */
59 if (iovcnt > (sizeof(liov) / sizeof(struct iovec))) {
60 /* Allocate memory for the local array: */
61 if ((p_iov = (struct iovec *)
62 malloc(iovcnt * sizeof(struct iovec))) == NULL) {
63 /* Insufficient memory: */
69 /* Copy the caller's array so that it can be modified locally: */
70 memcpy(p_iov,iov,iovcnt * sizeof(struct iovec));
72 /* Lock the file descriptor for write: */
73 if ((ret = _FD_LOCK(fd, FD_WRITE, NULL)) == 0) {
74 /* Get the read/write mode type: */
75 type = _thread_fd_getflags(fd) & O_ACCMODE;
77 /* Check if the file is not open for write: */
78 if (type != O_WRONLY && type != O_RDWR) {
79 /* File is not open for write: */
81 _FD_UNLOCK(fd, FD_WRITE);
85 /* Check if file operations are to block */
86 blocking = ((_thread_fd_getflags(fd) & O_NONBLOCK) == 0);
89 * Loop while no error occurs and until the expected number
90 * of bytes are written if performing a blocking write:
93 /* Perform a non-blocking write syscall: */
94 n = __sys_writev(fd, &p_iov[idx], iovcnt - idx);
96 /* Check if one or more bytes were written: */
99 * Keep a count of the number of bytes
105 * Enter a loop to check if a short write
106 * occurred and move the index to the
107 * array entry where the short write
111 while (cnt > 0 && idx < iovcnt) {
113 * If the residual count exceeds
114 * the size of this vector, then
115 * it was completely written:
117 if (cnt >= p_iov[idx].iov_len)
119 * Decrement the residual
120 * count and increment the
121 * index to the next array
124 cnt -= p_iov[idx++].iov_len;
127 * This entry was only
128 * partially written, so
130 * and base pointer ready
131 * for the next write:
133 p_iov[idx].iov_len -= cnt;
134 p_iov[idx].iov_base =
135 (char *)p_iov[idx].iov_base
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();