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 $
|
| 32 * $Id: uthread_writev.c,v 1.8 1998/06/09 23:21:05 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 int type; |
52 ssize_t cnt;
53 ssize_t n;
54 ssize_t num = 0;
55 ssize_t ret;
56 struct iovec liov[20];
57 struct iovec *p_iov = liov;
58
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: */
65 errno = ENOMEM;
66 return (-1);
67 }
68 }
69
70 /* Copy the caller's array so that it can be modified locally: */
71 memcpy(p_iov,iov,iovcnt * sizeof(struct iovec));
72
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_table[fd]->flags & O_ACCMODE;
77
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: */
81 errno = EBADF;
82 _FD_UNLOCK(fd, FD_WRITE);
83 return (-1);
84 }
85 |
86 /* Check if file operations are to block */
87 blocking = ((_thread_fd_table[fd]->flags & O_NONBLOCK) == 0);
88
89 /*
90 * Loop while no error occurs and until the expected number
91 * of bytes are written if performing a blocking write:
92 */
93 while (ret == 0) {
94 /* Perform a non-blocking write syscall: */
95 n = _thread_sys_writev(fd, &p_iov[idx], iovcnt - idx);
96
97 /* Check if one or more bytes were written: */
98 if (n > 0) {
99 /*
100 * Keep a count of the number of bytes
101 * written:
102 */
103 num += n;
104
105 /*
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
109 * ended:
110 */
111 cnt = n;
112 while (cnt > 0 && idx < iovcnt) {
113 /*
114 * If the residual count exceeds
115 * the size of this vector, then
116 * it was completely written:
117 */
118 if (cnt >= p_iov[idx].iov_len)
119 /*
120 * Decrement the residual
121 * count and increment the
122 * index to the next array
123 * entry:
124 */
125 cnt -= p_iov[idx++].iov_len;
126 else {
127 /*
128 * This entry was only
129 * partially written, so
130 * adjust it's length
131 * and base pointer ready
132 * for the next write:
133 */
134 p_iov[idx].iov_len -= cnt;
135 p_iov[idx].iov_base += cnt;
136 cnt = 0;
137 }
138 }
139 }
140
141 /*
142 * If performing a blocking write, check if the
143 * write would have blocked or if some bytes
144 * were written but there are still more to
145 * write:
146 */
147 if (blocking && ((n < 0 && (errno == EWOULDBLOCK ||
148 errno == EAGAIN)) || idx < iovcnt)) {
149 _thread_run->data.fd.fd = fd;
150 _thread_kern_set_timeout(NULL);
151
152 /* Reset the interrupted operation flag: */
153 _thread_run->interrupted = 0;
154
155 _thread_kern_sched_state(PS_FDW_WAIT,
156 __FILE__, __LINE__);
157
158 /*
159 * Check if the operation was
160 * interrupted by a signal
161 */
162 if (_thread_run->interrupted) {
163 /* Return an error: */
164 ret = -1;
165 }
166
167 /*
168 * If performing a non-blocking write or if an
169 * error occurred, just return whatever the write
170 * syscall did:
171 */
172 } else if (!blocking || n < 0) {
173 /* A non-blocking call might return zero: */
174 ret = n;
175 break;
176
177 /* Check if the write has completed: */
178 } else if (idx == iovcnt)
179 /* Return the number of bytes written: */
180 ret = num;
181 }
182 _FD_UNLOCK(fd, FD_RDWR);
183 }
184
185 /* If memory was allocated for the array, free it: */
186 if (p_iov != liov)
187 free(p_iov);
188
189 return (ret);
190}
191#endif
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