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8271308: (fc) FileChannel.transferTo() transfers no more than Integer.MAX_VALUE bytes in one call

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Reviewed-by: alanb, vtewari
This commit is contained in:
Brian Burkhalter 2021-08-05 16:10:04 +00:00
parent 7234a433f8
commit e2c5bfe083
4 changed files with 183 additions and 16 deletions
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32
src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -65,6 +65,9 @@ public class FileChannelImpl
private static final JavaIOFileDescriptorAccess fdAccess =
SharedSecrets.getJavaIOFileDescriptorAccess();
// Maximum direct transfer size
private static final int MAX_DIRECT_TRANSFER_SIZE;
// Used to make native read and write calls
private final FileDispatcher nd;
@ -622,18 +625,18 @@ public class FileChannelImpl
return count - remaining;
}
private long transferToArbitraryChannel(long position, int icount,
private long transferToArbitraryChannel(long position, long count,
WritableByteChannel target)
throws IOException
{
// Untrusted target: Use a newly-erased buffer
int c = Math.min(icount, TRANSFER_SIZE);
int c = (int)Math.min(count, TRANSFER_SIZE);
ByteBuffer bb = ByteBuffer.allocate(c);
long tw = 0; // Total bytes written
long pos = position;
try {
while (tw < icount) {
bb.limit(Math.min((int)(icount - tw), TRANSFER_SIZE));
while (tw < count) {
bb.limit((int)Math.min(count - tw, TRANSFER_SIZE));
int nr = read(bb, pos);
if (nr <= 0)
break;
@ -672,22 +675,23 @@ public class FileChannelImpl
long sz = size();
if (position > sz)
return 0;
int icount = (int)Math.min(count, Integer.MAX_VALUE);
if ((sz - position) < icount)
icount = (int)(sz - position);
if ((sz - position) < count)
count = (int)(sz - position);
// Attempt a direct transfer, if the kernel supports it, limiting
// the number of bytes according to which platform
int icount = (int)Math.min(count, MAX_DIRECT_TRANSFER_SIZE);
long n;
// Attempt a direct transfer, if the kernel supports it
if ((n = transferToDirectly(position, icount, target)) >= 0)
return n;
// Attempt a mapped transfer, but only to trusted channel types
if ((n = transferToTrustedChannel(position, icount, target)) >= 0)
if ((n = transferToTrustedChannel(position, count, target)) >= 0)
return n;
// Slow path for untrusted targets
return transferToArbitraryChannel(position, icount, target);
return transferToArbitraryChannel(position, count, target);
}
private long transferFromFileChannel(FileChannelImpl src,
@ -1348,11 +1352,15 @@ public class FileChannelImpl
private native long transferTo0(FileDescriptor src, long position,
long count, FileDescriptor dst);
// Retrieves the maximum size of a transfer
private static native int maxDirectTransferSize0();
// Caches fieldIDs
private static native long initIDs();
static {
IOUtil.load();
allocationGranularity = initIDs();
MAX_DIRECT_TRANSFER_SIZE = maxDirectTransferSize0();
}
}