1 /*
2 * Copyright (c) 2000, 2021, 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
26 #include <sys/types.h>
27 #include <string.h>
28 #include <sys/resource.h>
29
30 #include "jni.h"
31 #include "jni_util.h"
32 #include "jvm.h"
33 #include "jlong.h"
34 #include "sun_nio_ch_IOUtil.h"
35 #include "java_lang_Integer.h"
36 #include "java_lang_Long.h"
37 #include "nio.h"
38 #include "nio_util.h"
39
40 static jfieldID fd_fdID; /* for jint 'fd' in java.io.FileDescriptor */
41
42
43 JNIEXPORT void JNICALL
44 Java_sun_nio_ch_IOUtil_initIDs(JNIEnv *env, jclass clazz)
45 {
46 CHECK_NULL(clazz = (*env)->FindClass(env, "java/io/FileDescriptor"));
47 CHECK_NULL(fd_fdID = (*env)->GetFieldID(env, clazz, "fd", "I"));
48 }
49
50 JNIEXPORT jboolean JNICALL
51 Java_sun_nio_ch_IOUtil_randomBytes(JNIEnv *env, jclass clazz,
52 jbyteArray randArray)
53 {
54 JNU_ThrowByName(env, "java/lang/UnsupportedOperationException", NULL);
55 return JNI_FALSE;
56 }
57
58 JNIEXPORT jint JNICALL
59 Java_sun_nio_ch_IOUtil_fdVal(JNIEnv *env, jclass clazz, jobject fdo)
60 {
61 return (*env)->GetIntField(env, fdo, fd_fdID);
62 }
63
64 JNIEXPORT void JNICALL
65 Java_sun_nio_ch_IOUtil_setfdVal(JNIEnv *env, jclass clazz, jobject fdo, jint val)
66 {
67 setfdval(env, fdo, val);
68 }
69
70 static int
71 configureBlocking(int fd, jboolean blocking)
72 {
73 int flags = fcntl(fd, F_GETFL);
74 int newflags = blocking ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK);
75
76 return (flags == newflags) ? 0 : fcntl(fd, F_SETFL, newflags);
77 }
78
79 JNIEXPORT void JNICALL
80 Java_sun_nio_ch_IOUtil_configureBlocking(JNIEnv *env, jclass clazz,
81 jobject fdo, jboolean blocking)
82 {
83 if (configureBlocking(fdval(env, fdo), blocking) < 0)
84 JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
85 }
86
87 JNIEXPORT jlong JNICALL
88 Java_sun_nio_ch_IOUtil_makePipe(JNIEnv *env, jobject this, jboolean blocking)
89 {
90 int fd[2];
91
92 if (pipe(fd) < 0) {
93 JNU_ThrowIOExceptionWithLastError(env, "Pipe failed");
94 return 0;
95 }
96 if (blocking == JNI_FALSE) {
97 if ((configureBlocking(fd[0], JNI_FALSE) < 0)
98 || (configureBlocking(fd[1], JNI_FALSE) < 0)) {
99 JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
100 close(fd[0]);
101 close(fd[1]);
102 return 0;
103 }
104 }
105 return ((jlong) fd[0] << 32) | (jlong) fd[1];
106 }
107
108 JNIEXPORT jint JNICALL
109 Java_sun_nio_ch_IOUtil_write1(JNIEnv *env, jclass cl, jint fd, jbyte b)
110 {
111 char c = (char)b;
112 return convertReturnVal(env, write(fd, &c, 1), JNI_FALSE);
113 }
114
115 JNIEXPORT jboolean JNICALL
116 Java_sun_nio_ch_IOUtil_drain(JNIEnv *env, jclass cl, jint fd)
117 {
118 char buf[16];
119 int tn = 0;
120
121 for (;;) {
122 int n = read(fd, buf, sizeof(buf));
123 tn += n;
124 if ((n < 0) && (errno != EAGAIN && errno != EWOULDBLOCK))
125 JNU_ThrowIOExceptionWithLastError(env, "Drain");
126 if (n == (int)sizeof(buf))
127 continue;
128 return (tn > 0) ? JNI_TRUE : JNI_FALSE;
129 }
130 }
131
132 JNIEXPORT jint JNICALL
133 Java_sun_nio_ch_IOUtil_drain1(JNIEnv *env, jclass cl, jint fd)
134 {
135 int res;
136 char buf[1];
137
138 res = read(fd, buf, 1);
139 if (res < 0) {
140 if (errno == EAGAIN || errno == EWOULDBLOCK) {
141 res = 0;
142 } else if (errno == EINTR) {
143 return IOS_INTERRUPTED;
144 } else {
145 JNU_ThrowIOExceptionWithLastError(env, "read");
146 return IOS_THROWN;
147 }
148 }
149 return res;
150 }
151
152 JNIEXPORT jint JNICALL
153 Java_sun_nio_ch_IOUtil_fdLimit(JNIEnv *env, jclass this)
154 {
155 struct rlimit rlp;
156 if (getrlimit(RLIMIT_NOFILE, &rlp) < 0) {
157 JNU_ThrowIOExceptionWithLastError(env, "getrlimit failed");
158 return -1;
159 }
160 if (rlp.rlim_max == RLIM_INFINITY ||
161 rlp.rlim_max > (rlim_t)java_lang_Integer_MAX_VALUE) {
162 return java_lang_Integer_MAX_VALUE;
163 } else {
164 return (jint)rlp.rlim_max;
165 }
166 }
167
168 JNIEXPORT jint JNICALL
169 Java_sun_nio_ch_IOUtil_iovMax(JNIEnv *env, jclass this)
170 {
171 jlong iov_max = sysconf(_SC_IOV_MAX);
172 if (iov_max == -1)
173 iov_max = 16;
174 return (jint)iov_max;
175 }
176
177 JNIEXPORT jlong JNICALL
178 Java_sun_nio_ch_IOUtil_writevMax(JNIEnv *env, jclass this)
179 {
180 #if defined(MACOSX) || defined(__linux__)
181 //
182 // The man pages of writev() on both Linux and macOS specify this
183 // constraint on the sum of all byte lengths in the iovec array:
184 //
185 // [EINVAL] The sum of the iov_len values in the iov array
186 // overflows a 32-bit integer.
187 //
188 // As of macOS 11 Big Sur, Darwin version 20, writev() started to
189 // actually enforce the constraint which had been previously ignored.
190 //
191 // In practice on Linux writev() has been observed not to write more
192 // than 0x7fff0000 (aarch64) or 0x7ffff000 (x64) bytes in one call.
193 //
194 return java_lang_Integer_MAX_VALUE;
195 #else
196 return java_lang_Long_MAX_VALUE;
197 #endif
198 }
199
200 /* Declared in nio_util.h for use elsewhere in NIO */
201
202 jint
203 convertReturnVal(JNIEnv *env, jint n, jboolean reading)
204 {
205 if (n > 0) /* Number of bytes written */
206 return n;
207 else if (n == 0) {
208 if (reading) {
209 return IOS_EOF; /* EOF is -1 in javaland */
210 } else {
211 return 0;
212 }
213 }
214 else if (errno == EAGAIN || errno == EWOULDBLOCK)
215 return IOS_UNAVAILABLE;
216 else if (errno == EINTR)
217 return IOS_INTERRUPTED;
218 else {
219 const char *msg = reading ? "Read failed" : "Write failed";
220 JNU_ThrowIOExceptionWithLastError(env, msg);
221 return IOS_THROWN;
222 }
223 }
224
225 /* Declared in nio_util.h for use elsewhere in NIO */
226
227 jlong
228 convertLongReturnVal(JNIEnv *env, jlong n, jboolean reading)
229 {
230 if (n > 0) /* Number of bytes written */
231 return n;
232 else if (n == 0) {
233 if (reading) {
234 return IOS_EOF; /* EOF is -1 in javaland */
235 } else {
236 return 0;
237 }
238 }
239 else if (errno == EAGAIN || errno == EWOULDBLOCK)
240 return IOS_UNAVAILABLE;
241 else if (errno == EINTR)
242 return IOS_INTERRUPTED;
243 else {
244 const char *msg = reading ? "Read failed" : "Write failed";
245 JNU_ThrowIOExceptionWithLastError(env, msg);
246 return IOS_THROWN;
247 }
248 }
249
250 jint
251 fdval(JNIEnv *env, jobject fdo)
252 {
253 return (*env)->GetIntField(env, fdo, fd_fdID);
254 }
255
256 void
257 setfdval(JNIEnv *env, jobject fdo, jint val) {
258 (*env)->SetIntField(env, fdo, fd_fdID, val);
259 }
260
261