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The official Couchbase JVM Core IO Library
/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
#include
#include
#include
#include
#include
#include
#include
#include "netty_unix_errors.h"
#include "netty_unix_filedescriptor.h"
#include "netty_unix_jni.h"
#include "netty_unix_util.h"
#include "netty_jni_util.h"
#define FILEDESCRIPTOR_CLASSNAME "io/netty/channel/unix/FileDescriptor"
static jmethodID posId = NULL;
static jmethodID limitId = NULL;
static jfieldID posFieldId = NULL;
static jfieldID limitFieldId = NULL;
// Optional external methods
extern int pipe2(int pipefd[2], int flags) __attribute__((weak)) __attribute__((weak_import));
static jint _write(JNIEnv* env, jclass clazz, jint fd, void* buffer, jint pos, jint limit) {
ssize_t res;
int err;
do {
res = write(fd, buffer + pos, (size_t) (limit - pos));
// keep on writing if it was interrupted
} while (res == -1 && ((err = errno) == EINTR));
if (res < 0) {
return -err;
}
return (jint) res;
}
static jlong _writev(JNIEnv* env, jclass clazz, jint fd, struct iovec* iov, jint length) {
ssize_t res;
int err;
do {
res = writev(fd, iov, length);
// keep on writing if it was interrupted
} while (res == -1 && ((err = errno) == EINTR));
if (res < 0) {
return -err;
}
return (jlong) res;
}
static jint _read(JNIEnv* env, jclass clazz, jint fd, void* buffer, jint pos, jint limit) {
ssize_t res;
int err;
do {
res = read(fd, buffer + pos, (size_t) (limit - pos));
// Keep on reading if we was interrupted
} while (res == -1 && ((err = errno) == EINTR));
if (res < 0) {
return -err;
}
return (jint) res;
}
// JNI Registered Methods Begin
static jint netty_unix_filedescriptor_close(JNIEnv* env, jclass clazz, jint fd) {
if (close(fd) < 0) {
// There is really nothing "sane" we can do when EINTR was reported on close. So just ignore it and "assume"
// everything is fine == we closed the file descriptor.
//
// For more details see:
// - https://bugs.chromium.org/p/chromium/issues/detail?id=269623
// - https://lwn.net/Articles/576478/
if (errno != EINTR) {
return -errno;
}
}
return 0;
}
static jint netty_unix_filedescriptor_open(JNIEnv* env, jclass clazz, jstring path) {
const char* f_path = (*env)->GetStringUTFChars(env, path, 0);
int res = open(f_path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
(*env)->ReleaseStringUTFChars(env, path, f_path);
if (res < 0) {
return -errno;
}
return res;
}
static jint netty_unix_filedescriptor_write(JNIEnv* env, jclass clazz, jint fd, jobject jbuffer, jint pos, jint limit) {
// We check that GetDirectBufferAddress will not return NULL in OnLoad
return _write(env, clazz, fd, (*env)->GetDirectBufferAddress(env, jbuffer), pos, limit);
}
static jint netty_unix_filedescriptor_writeAddress(JNIEnv* env, jclass clazz, jint fd, jlong address, jint pos, jint limit) {
return _write(env, clazz, fd, (void*) (intptr_t) address, pos, limit);
}
static jlong netty_unix_filedescriptor_writevAddresses(JNIEnv* env, jclass clazz, jint fd, jlong memoryAddress, jint length) {
struct iovec* iov = (struct iovec*) (intptr_t) memoryAddress;
return _writev(env, clazz, fd, iov, length);
}
static jlong netty_unix_filedescriptor_writev(JNIEnv* env, jclass clazz, jint fd, jobjectArray buffers, const jint offset, jint length, jlong maxBytesToWrite) {
struct iovec iov[length];
struct iovec* iovptr = iov;
int i;
int num = offset + length;
if (posFieldId != NULL && limitFieldId != NULL) {
for (i = offset; i < num; ++i) {
jobject bufObj = (*env)->GetObjectArrayElement(env, buffers, i);
jint pos = (*env)->GetIntField(env, bufObj, posFieldId);
jint limit = (*env)->GetIntField(env, bufObj, limitFieldId);
size_t bytesLength = (size_t) (limit - pos);
if (bytesLength > maxBytesToWrite && i != offset) {
length = i - offset;
break;
}
maxBytesToWrite -= bytesLength;
void* buffer = (*env)->GetDirectBufferAddress(env, bufObj);
// We check that GetDirectBufferAddress will not return NULL in OnLoad
iovptr->iov_base = buffer + pos;
iovptr->iov_len = bytesLength;
++iovptr;
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
}
} else if (posFieldId != NULL && limitFieldId == NULL) {
for (i = offset; i < num; ++i) {
jobject bufObj = (*env)->GetObjectArrayElement(env, buffers, i);
jint pos = (*env)->GetIntField(env, bufObj, posFieldId);
jint limit = (*env)->CallIntMethod(env, bufObj, limitId, NULL);
size_t bytesLength = (size_t) (limit - pos);
if (bytesLength > maxBytesToWrite && i != offset) {
length = i - offset;
break;
}
maxBytesToWrite -= bytesLength;
void* buffer = (*env)->GetDirectBufferAddress(env, bufObj);
// We check that GetDirectBufferAddress will not return NULL in OnLoad
iovptr->iov_base = buffer + pos;
iovptr->iov_len = bytesLength;
++iovptr;
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
}
} else if (limitFieldId != NULL) {
for (i = offset; i < num; ++i) {
jobject bufObj = (*env)->GetObjectArrayElement(env, buffers, i);
jint pos = (*env)->CallIntMethod(env, bufObj, posId, NULL);
jint limit = (*env)->GetIntField(env, bufObj, limitFieldId);
size_t bytesLength = (size_t) (limit - pos);
if (bytesLength > maxBytesToWrite && i != offset) {
length = i - offset;
break;
}
maxBytesToWrite -= bytesLength;
void* buffer = (*env)->GetDirectBufferAddress(env, bufObj);
// We check that GetDirectBufferAddress will not return NULL in OnLoad
iovptr->iov_base = buffer + pos;
iovptr->iov_len = bytesLength;
++iovptr;
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
}
} else {
for (i = offset; i < num; ++i) {
jobject bufObj = (*env)->GetObjectArrayElement(env, buffers, i);
jint pos = (*env)->CallIntMethod(env, bufObj, posId, NULL);
jint limit = (*env)->CallIntMethod(env, bufObj, limitId, NULL);
size_t bytesLength = (size_t) (limit - pos);
if (bytesLength > maxBytesToWrite && i != offset) {
length = i - offset;
break;
}
maxBytesToWrite -= bytesLength;
void* buffer = (*env)->GetDirectBufferAddress(env, bufObj);
// We check that GetDirectBufferAddress will not return NULL in OnLoad
iovptr->iov_base = buffer + pos;
iovptr->iov_len = bytesLength;
++iovptr;
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
}
}
return _writev(env, clazz, fd, iov, length);
}
static jint netty_unix_filedescriptor_read(JNIEnv* env, jclass clazz, jint fd, jobject jbuffer, jint pos, jint limit) {
// We check that GetDirectBufferAddress will not return NULL in OnLoad
return _read(env, clazz, fd, (*env)->GetDirectBufferAddress(env, jbuffer), pos, limit);
}
static jint netty_unix_filedescriptor_readAddress(JNIEnv* env, jclass clazz, jint fd, jlong address, jint pos, jint limit) {
return _read(env, clazz, fd, (void*) (intptr_t) address, pos, limit);
}
static jlong netty_unix_filedescriptor_newPipe(JNIEnv* env, jclass clazz) {
int fd[2];
if (pipe2) {
// we can just use pipe2 and so save extra syscalls;
if (pipe2(fd, O_NONBLOCK) != 0) {
return -errno;
}
} else {
if (pipe(fd) == 0) {
if (fcntl(fd[0], F_SETFD, O_NONBLOCK) < 0) {
int err = errno;
close(fd[0]);
close(fd[1]);
return -err;
}
if (fcntl(fd[1], F_SETFD, O_NONBLOCK) < 0) {
int err = errno;
close(fd[0]);
close(fd[1]);
return -err;
}
} else {
return -errno;
}
}
// encode the fds into a 64 bit value
return (((jlong) fd[0]) << 32) | fd[1];
}
// JNI Registered Methods End
// JNI Method Registration Table Begin
static const JNINativeMethod method_table[] = {
{ "close", "(I)I", (void *) netty_unix_filedescriptor_close },
{ "open", "(Ljava/lang/String;)I", (void *) netty_unix_filedescriptor_open },
{ "write", "(ILjava/nio/ByteBuffer;II)I", (void *) netty_unix_filedescriptor_write },
{ "writeAddress", "(IJII)I", (void *) netty_unix_filedescriptor_writeAddress },
{ "writevAddresses", "(IJI)J", (void *) netty_unix_filedescriptor_writevAddresses },
{ "writev", "(I[Ljava/nio/ByteBuffer;IIJ)J", (void *) netty_unix_filedescriptor_writev },
{ "read", "(ILjava/nio/ByteBuffer;II)I", (void *) netty_unix_filedescriptor_read },
{ "readAddress", "(IJII)I", (void *) netty_unix_filedescriptor_readAddress },
{ "newPipe", "()J", (void *) netty_unix_filedescriptor_newPipe }
};
static const jint method_table_size = sizeof(method_table) / sizeof(method_table[0]);
// JNI Method Registration Table End
// IMPORTANT: If you add any NETTY_JNI_UTIL_LOAD_CLASS or NETTY_JNI_UTIL_FIND_CLASS calls you also need to update
// Unix to reflect that.
jint netty_unix_filedescriptor_JNI_OnLoad(JNIEnv* env, const char* packagePrefix) {
int ret = JNI_ERR;
void* mem = NULL;
if (netty_jni_util_register_natives(env, packagePrefix, FILEDESCRIPTOR_CLASSNAME, method_table, method_table_size) != 0) {
goto done;
}
if ((mem = malloc(1)) == NULL) {
goto done;
}
jobject directBuffer = (*env)->NewDirectByteBuffer(env, mem, 1);
if (directBuffer == NULL) {
goto done;
}
if ((*env)->GetDirectBufferAddress(env, directBuffer) == NULL) {
goto done;
}
jclass cls = (*env)->GetObjectClass(env, directBuffer);
if (cls == NULL) {
goto done;
}
// Get the method id for Buffer.position() and Buffer.limit(). These are used as fallback if
// it is not possible to obtain the position and limit using the fields directly.
NETTY_JNI_UTIL_GET_METHOD(env, cls, posId, "position", "()I", done);
NETTY_JNI_UTIL_GET_METHOD(env, cls, limitId, "limit", "()I", done);
// Try to get the ids of the position and limit fields. We later then check if we was able
// to find them and if so use them get the position and limit of the buffer. This is
// much faster then call back into java via (*env)->CallIntMethod(...).
NETTY_JNI_UTIL_TRY_GET_FIELD(env, cls, posFieldId, "position", "I");
NETTY_JNI_UTIL_TRY_GET_FIELD(env, cls, limitFieldId, "limit", "I");
ret = NETTY_JNI_UTIL_JNI_VERSION;
done:
free(mem);
return ret;
}
void netty_unix_filedescriptor_JNI_OnUnLoad(JNIEnv* env, const char* packagePrefix) {
netty_jni_util_unregister_natives(env, packagePrefix, FILEDESCRIPTOR_CLASSNAME);
}