1 /*
2 * Copyright (c) 2000, 2025, 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, jint fd, jboolean blocking)
81 {
82 if (configureBlocking(fd, blocking) < 0)
83 JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
84 }
85
86 JNIEXPORT jlong JNICALL
87 Java_sun_nio_ch_IOUtil_makePipe(JNIEnv *env, jobject this, jboolean blocking)
88 {
89 int fd[2];
90
91 if (pipe(fd) < 0) {
92 JNU_ThrowIOExceptionWithLastError(env, "Pipe failed");
93 return 0;
94 }
95 if (blocking == JNI_FALSE) {
96 if ((configureBlocking(fd[0], JNI_FALSE) < 0)
97 || (configureBlocking(fd[1], JNI_FALSE) < 0)) {
98 JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
99 close(fd[0]);
100 close(fd[1]);
101 return 0;
102 }
103 }
104 return ((jlong) fd[0] << 32) | (jlong) fd[1];
105 }
106
107 JNIEXPORT jint JNICALL
108 Java_sun_nio_ch_IOUtil_write1(JNIEnv *env, jclass cl, jint fd, jbyte b)
109 {
110 char c = (char)b;
111 return convertReturnVal(env, write(fd, &c, 1), JNI_FALSE);
112 }
113
114 JNIEXPORT jboolean JNICALL
115 Java_sun_nio_ch_IOUtil_drain(JNIEnv *env, jclass cl, jint fd)
116 {
117 char buf[16];
118 int tn = 0;
119
120 for (;;) {
121 int n = read(fd, buf, sizeof(buf));
122 tn += n;
123 if ((n < 0) && (errno != EAGAIN && errno != EWOULDBLOCK))
124 JNU_ThrowIOExceptionWithLastError(env, "Drain");
125 if (n == (int)sizeof(buf))
126 continue;
127 return (tn > 0) ? JNI_TRUE : JNI_FALSE;
128 }
129 }
130
131 JNIEXPORT jint JNICALL
132 Java_sun_nio_ch_IOUtil_drain1(JNIEnv *env, jclass cl, jint fd)
133 {
134 int res;
135 char buf[1];
136
137 res = read(fd, buf, 1);
138 if (res < 0) {
139 if (errno == EAGAIN || errno == EWOULDBLOCK) {
140 res = 0;
141 } else if (errno == EINTR) {
142 return IOS_INTERRUPTED;
143 } else {
144 JNU_ThrowIOExceptionWithLastError(env, "read");
145 return IOS_THROWN;
146 }
147 }
148 return res;
149 }
150
151 JNIEXPORT jint JNICALL
152 Java_sun_nio_ch_IOUtil_fdLimit(JNIEnv *env, jclass this)
153 {
154 struct rlimit rlp;
155 if (getrlimit(RLIMIT_NOFILE, &rlp) < 0) {
156 JNU_ThrowIOExceptionWithLastError(env, "getrlimit failed");
157 return -1;
158 }
159 if (rlp.rlim_max == RLIM_INFINITY ||
160 rlp.rlim_max > (rlim_t)java_lang_Integer_MAX_VALUE) {
161 return java_lang_Integer_MAX_VALUE;
162 } else {
163 return (jint)rlp.rlim_max;
164 }
165 }
166
167 JNIEXPORT jint JNICALL
168 Java_sun_nio_ch_IOUtil_iovMax(JNIEnv *env, jclass this)
169 {
170 jlong iov_max = sysconf(_SC_IOV_MAX);
171 if (iov_max == -1)
172 iov_max = 16;
173 return (jint)iov_max;
174 }
175
176 JNIEXPORT jlong JNICALL
177 Java_sun_nio_ch_IOUtil_writevMax(JNIEnv *env, jclass this)
178 {
179 #if defined(MACOSX) || defined(__linux__)
180 //
181 // The man pages of writev() on both Linux and macOS specify this
182 // constraint on the sum of all byte lengths in the iovec array:
183 //
184 // [EINVAL] The sum of the iov_len values in the iov array
185 // overflows a 32-bit integer.
186 //
187 // As of macOS 11 Big Sur, Darwin version 20, writev() started to
188 // actually enforce the constraint which had been previously ignored.
189 //
190 // In practice on Linux writev() has been observed not to write more
191 // than 0x7fff0000 (aarch64) or 0x7ffff000 (x64) bytes in one call.
192 //
193 return java_lang_Integer_MAX_VALUE;
194 #else
195 return java_lang_Long_MAX_VALUE;
196 #endif
197 }
198
199 /* Declared in nio_util.h for use elsewhere in NIO */
200
201 jint
202 convertReturnVal(JNIEnv *env, jint n, jboolean reading)
203 {
204 if (n > 0) /* Number of bytes written */
205 return n;
206 else if (n == 0) {
207 if (reading) {
208 return IOS_EOF; /* EOF is -1 in javaland */
209 } else {
210 return 0;
211 }
212 }
213 else if (errno == EAGAIN || errno == EWOULDBLOCK)
214 return IOS_UNAVAILABLE;
215 else if (errno == EINTR)
216 return IOS_INTERRUPTED;
217 else {
218 const char *msg = reading ? "Read failed" : "Write failed";
219 JNU_ThrowIOExceptionWithLastError(env, msg);
220 return IOS_THROWN;
221 }
222 }
223
224 /* Declared in nio_util.h for use elsewhere in NIO */
225
226 jlong
227 convertLongReturnVal(JNIEnv *env, jlong n, jboolean reading)
228 {
229 if (n > 0) /* Number of bytes written */
230 return n;
231 else if (n == 0) {
232 if (reading) {
233 return IOS_EOF; /* EOF is -1 in javaland */
234 } else {
235 return 0;
236 }
237 }
238 else if (errno == EAGAIN || errno == EWOULDBLOCK)
239 return IOS_UNAVAILABLE;
240 else if (errno == EINTR)
241 return IOS_INTERRUPTED;
242 else {
243 const char *msg = reading ? "Read failed" : "Write failed";
244 JNU_ThrowIOExceptionWithLastError(env, msg);
245 return IOS_THROWN;
246 }
247 }
248
249 jint
250 fdval(JNIEnv *env, jobject fdo)
251 {
252 return (*env)->GetIntField(env, fdo, fd_fdID);
253 }
254
255 void
256 setfdval(JNIEnv *env, jobject fdo, jint val) {
257 (*env)->SetIntField(env, fdo, fd_fdID, val);
258 }
259
260