1 /*
2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 #include <malloc.h>
26
27 #include "net_util.h"
28
29 #include "java_net_SocketOutputStream.h"
30
31 /************************************************************************
32 * SocketOutputStream
33 */
34 static jfieldID IO_fd_fdID;
35
36 /*
37 * Class: java_net_SocketOutputStream
38 * Method: init
39 * Signature: ()V
40 */
41 JNIEXPORT void JNICALL
42 Java_java_net_SocketOutputStream_init(JNIEnv *env, jclass cls) {
43 IO_fd_fdID = NET_GetFileDescriptorID(env);
44 }
45
46 /*
47 * Class: java_net_SocketOutputStream
48 * Method: socketWrite
49 * Signature: (Ljava/io/FileDescriptor;[BII)V
50 */
51 JNIEXPORT void JNICALL
52 Java_java_net_SocketOutputStream_socketWrite0(JNIEnv *env, jobject this,
53 jobject fdObj, jbyteArray data,
54 jint off, jint len) {
55 char *bufP;
56 char BUF[MAX_BUFFER_LEN];
57 int buflen;
58 int fd;
59
60 if (IS_NULL(fdObj)) {
61 JNU_ThrowByName(env, JNU_JAVANETPKG "SocketException", "Socket closed");
62 return;
63 } else {
64 fd = (*env)->GetIntField(env, fdObj, IO_fd_fdID);
65 }
66 if (IS_NULL(data)) {
67 JNU_ThrowNullPointerException(env, "data argument");
68 return;
69 }
70
71 /*
72 * Use stack allocate buffer if possible. For large sizes we allocate
73 * an intermediate buffer from the heap (up to a maximum). If heap is
74 * unavailable just use our stack buffer.
75 */
76 if (len <= MAX_BUFFER_LEN) {
77 bufP = BUF;
78 buflen = MAX_BUFFER_LEN;
79 } else {
80 buflen = min(MAX_HEAP_BUFFER_LEN, len);
81 bufP = (char *)malloc((size_t)buflen);
82 if (bufP == NULL) {
83 bufP = BUF;
84 buflen = MAX_BUFFER_LEN;
85 }
86 }
87
88 while(len > 0) {
89 int loff = 0;
90 int chunkLen = min(buflen, len);
91 int llen = chunkLen;
92 int retry = 0;
93
94 (*env)->GetByteArrayRegion(env, data, off, chunkLen, (jbyte *)bufP);
95 if ((*env)->ExceptionCheck(env)) {
96 break;
97 } else {
98 while(llen > 0) {
99 int n = send(fd, bufP + loff, llen, 0);
100 if (n > 0) {
101 JVM_callFileWriteBytes(env, n);
102 llen -= n;
103 loff += n;
104 continue;
105 }
106
107 /*
108 * Due to a bug in Windows Sockets (observed on NT and Windows
109 * 2000) it may be necessary to retry the send. The issue is that
110 * on blocking sockets send/WSASend is supposed to block if there
111 * is insufficient buffer space available. If there are a large
112 * number of threads blocked on write due to congestion then it's
113 * possile to hit the NT/2000 bug whereby send returns WSAENOBUFS.
114 * The workaround we use is to retry the send. If we have a
115 * large buffer to send (>2k) then we retry with a maximum of
116 * 2k buffer. If we hit the issue with <=2k buffer then we backoff
117 * for 1 second and retry again. We repeat this up to a reasonable
118 * limit before bailing out and throwing an exception. In load
119 * conditions we've observed that the send will succeed after 2-3
120 * attempts but this depends on network buffers associated with
121 * other sockets draining.
122 */
123 if (WSAGetLastError() == WSAENOBUFS) {
124 if (llen > MAX_BUFFER_LEN) {
125 buflen = MAX_BUFFER_LEN;
126 chunkLen = MAX_BUFFER_LEN;
127 llen = MAX_BUFFER_LEN;
128 continue;
129 }
130 if (retry >= 30) {
131 JNU_ThrowByName(env, JNU_JAVANETPKG "SocketException",
132 "No buffer space available - exhausted attempts to queue buffer");
133 if (bufP != BUF) {
134 free(bufP);
135 }
136 return;
137 }
138 Sleep(1000);
139 retry++;
140 continue;
141 }
142
143 /*
144 * Send failed - can be caused by close or write error.
145 */
146 if (WSAGetLastError() == WSAENOTSOCK) {
147 JNU_ThrowByName(env, JNU_JAVANETPKG "SocketException", "Socket closed");
148 } else {
149 NET_ThrowCurrent(env, "socket write error");
150 }
151 if (bufP != BUF) {
152 free(bufP);
153 }
154 return;
155 }
156 len -= chunkLen;
157 off += chunkLen;
158 }
159 }
160
161 if (bufP != BUF) {
162 free(bufP);
163 }
164 }