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 1.7 1998/05/27 00:44:58 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 <stdlib.h>
40#include <string.h>
41#include <unistd.h>
42#ifdef _THREAD_SAFE
43#include <pthread.h>
44#include "pthread_private.h"
45
46ssize_t
47writev(int fd, const struct iovec * iov, int iovcnt)
48{
49 int blocking;
50 int idx = 0;
51 ssize_t cnt;
52 ssize_t n;
53 ssize_t num = 0;
54 ssize_t ret;
55 struct iovec liov[20];
56 struct iovec *p_iov = liov;
57
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: */
64 errno = ENOMEM;
65 return (-1);
66 }
67 }
68
69 /* Copy the caller's array so that it can be modified locally: */
70 memcpy(p_iov,iov,iovcnt * sizeof(struct iovec));
71
72 /* Lock the file descriptor for write: */
73 if ((ret = _FD_LOCK(fd, FD_WRITE, NULL)) == 0) {
74 /* Check if file operations are to block */
75 blocking = ((_thread_fd_table[fd]->flags & O_NONBLOCK) == 0);
76
77 /*
78 * Loop while no error occurs and until the expected number
79 * of bytes are written if performing a blocking write:
80 */
81 while (ret == 0) {
82 /* Perform a non-blocking write syscall: */
83 n = _thread_sys_writev(fd, &p_iov[idx], iovcnt - idx);
84
85 /* Check if one or more bytes were written: */
86 if (n > 0) {
87 /*
88 * Keep a count of the number of bytes
89 * written:
90 */
91 num += n;
92
93 /*
94 * Enter a loop to check if a short write
95 * occurred and move the index to the
96 * array entry where the short write
97 * ended:
98 */
99 cnt = n;
100 while (cnt > 0 && idx < iovcnt) {
101 /*
102 * If the residual count exceeds
103 * the size of this vector, then
104 * it was completely written:
105 */
106 if (cnt >= p_iov[idx].iov_len)
107 /*
108 * Decrement the residual
109 * count and increment the
110 * index to the next array
111 * entry:
112 */
113 cnt -= p_iov[idx++].iov_len;
114 else {
115 /*
116 * This entry was only
117 * partially written, so
118 * adjust it's length
119 * and base pointer ready
120 * for the next write:
121 */
122 p_iov[idx].iov_len -= cnt;
123 p_iov[idx].iov_base += cnt;
124 cnt = 0;
125 }
126 }
127 }
128
129 /*
130 * If performing a blocking write, check if the
131 * write would have blocked or if some bytes
132 * were written but there are still more to
133 * write:
134 */
135 if (blocking && ((n < 0 && (errno == EWOULDBLOCK ||
136 errno == EAGAIN)) || idx < iovcnt)) {
137 _thread_run->data.fd.fd = fd;
138 _thread_kern_set_timeout(NULL);
139
140 /* Reset the interrupted operation flag: */
141 _thread_run->interrupted = 0;
142
143 _thread_kern_sched_state(PS_FDW_WAIT,
144 __FILE__, __LINE__);
145
146 /*
147 * Check if the operation was
148 * interrupted by a signal
149 */
150 if (_thread_run->interrupted) {
151 /* Return an error: */
152 ret = -1;
153 }
154
155 /*
156 * If performing a non-blocking write or if an
157 * error occurred, just return whatever the write
158 * syscall did:
159 */
160 } else if (!blocking || n < 0) {
161 /* A non-blocking call might return zero: */
162 ret = n;
163 break;
164
165 /* Check if the write has completed: */
166 } else if (idx == iovcnt)
167 /* Return the number of bytes written: */
168 ret = num;
169 }
170 _FD_UNLOCK(fd, FD_RDWR);
171 }
172
173 /* If memory was allocated for the array, free it: */
174 if (p_iov != liov)
175 free(p_iov);
176
177 return (ret);
178}
179#endif