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diff --git a/src/VBox/Runtime/r3/linux/RTFileCopyPartEx-linux.cpp b/src/VBox/Runtime/r3/linux/RTFileCopyPartEx-linux.cpp
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+++ b/src/VBox/Runtime/r3/linux/RTFileCopyPartEx-linux.cpp
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+/* $Id: RTFileCopyPartEx-linux.cpp $ */
+/** @file
+ * IPRT - RTFileCopyPartEx, linux specific implementation.
+ */
+
+/*
+ * Copyright (C) 2006-2020 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+* Header Files *
+*********************************************************************************************************************************/
+#include <iprt/file.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#ifndef __NR_copy_file_range
+# if defined(RT_ARCH_X86)
+# define __NR_copy_file_range 377
+# elif defined(RT_ARCH_AMD64)
+# define __NR_copy_file_range 326
+# endif
+#endif
+
+
+#ifndef __NR_copy_file_range
+# include "../../generic/RTFileCopyPartEx-generic.cpp"
+#else /* __NR_copy_file_range - whole file */
+/* Include the generic code as a fallback since copy_file_range is rather new . */
+# define IPRT_FALLBACK_VERSION
+# include "../../generic/RTFileCopyPartEx-generic.cpp"
+# undef IPRT_FALLBACK_VERSION
+
+
+/*********************************************************************************************************************************
+* Global Variables *
+*********************************************************************************************************************************/
+static int32_t volatile g_fCopyFileRangeSupported = -1;
+
+
+DECLINLINE(loff_t)
+MyCopyFileRangeSysCall(int fdIn, loff_t *poffIn, int fdOut, loff_t *poffOut, size_t cbChunk, unsigned int fFlags)
+{
+ return syscall(__NR_copy_file_range, fdIn, poffIn, fdOut, poffOut, cbChunk, fFlags);
+}
+
+
+DECL_NO_INLINE(static, bool) HasCopyFileRangeSyscallSlow(void)
+{
+ errno = 0;
+ MyCopyFileRangeSysCall(-1, NULL, -1, NULL, 4096, 0);
+ if (errno != ENOSYS)
+ {
+ ASMAtomicWriteS32(&g_fCopyFileRangeSupported, 1);
+ return true;
+ }
+ ASMAtomicWriteS32(&g_fCopyFileRangeSupported, 0);
+ return false;
+}
+
+DECLINLINE(bool) HasCopyFileRangeSyscall(void)
+{
+ int32_t i = ASMAtomicUoReadS32(&g_fCopyFileRangeSupported);
+ if (i != -1)
+ return i == 1;
+ return HasCopyFileRangeSyscallSlow();
+}
+
+
+
+RTDECL(int) RTFileCopyPartPrep(PRTFILECOPYPARTBUFSTATE pBufState, uint64_t cbToCopy)
+{
+ if (HasCopyFileRangeSyscall())
+ {
+ pBufState->iAllocType = -42;
+ pBufState->pbBuf = NULL;
+ pBufState->cbBuf = 0;
+ pBufState->uMagic = RTFILECOPYPARTBUFSTATE_MAGIC;
+ return VINF_SUCCESS;
+ }
+ return rtFileCopyPartPrepFallback(pBufState, cbToCopy);
+}
+
+
+RTDECL(void) RTFileCopyPartCleanup(PRTFILECOPYPARTBUFSTATE pBufState)
+{
+ return rtFileCopyPartCleanupFallback(pBufState);
+}
+
+
+RTDECL(int) RTFileCopyPartEx(RTFILE hFileSrc, RTFOFF offSrc, RTFILE hFileDst, RTFOFF offDst, uint64_t cbToCopy,
+ uint32_t fFlags, PRTFILECOPYPARTBUFSTATE pBufState, uint64_t *pcbCopied)
+{
+ /*
+ * Validate input.
+ */
+ if (pcbCopied)
+ *pcbCopied = 0;
+ AssertReturn(pBufState->uMagic == RTFILECOPYPARTBUFSTATE_MAGIC, VERR_INVALID_FLAGS);
+ if (pBufState->iAllocType == -42)
+ { /* more and more likely as time goes */ }
+ else
+ return rtFileCopyPartExFallback(hFileSrc, offSrc, hFileDst, offDst, cbToCopy, fFlags, pBufState, pcbCopied);
+ AssertReturn(offSrc >= 0, VERR_NEGATIVE_SEEK);
+ AssertReturn(offDst >= 0, VERR_NEGATIVE_SEEK);
+ AssertReturn(!fFlags, VERR_INVALID_FLAGS);
+
+ /*
+ * If nothing to copy, return right away.
+ */
+ if (!cbToCopy)
+ return VINF_SUCCESS;
+
+ /*
+ * Do the copying.
+ */
+ uint64_t cbCopied = 0;
+ int rc = VINF_SUCCESS;
+ do
+ {
+ size_t cbThisCopy = (size_t)RT_MIN(cbToCopy - cbCopied, _1G);
+ loff_t offThisDst = offSrc + cbCopied;
+ loff_t offThisSrc = offDst + cbCopied;
+ ssize_t cbActual = MyCopyFileRangeSysCall((int)RTFileToNative(hFileSrc), &offThisSrc,
+ (int)RTFileToNative(hFileDst), &offThisDst,
+ cbThisCopy, 0);
+ if (cbActual < 0)
+ {
+ rc = errno;
+ Assert(rc != 0);
+ rc = rc != 0 ? RTErrConvertFromErrno(rc) : VERR_READ_ERROR;
+ if (rc != VERR_NOT_SAME_DEVICE || cbCopied != 0)
+ break;
+
+ /* Fall back to generic implementation if the syscall refuses to handle the case. */
+ rc = rtFileCopyPartPrepFallback(pBufState, cbToCopy);
+ if (RT_SUCCESS(rc))
+ return rtFileCopyPartExFallback(hFileSrc, offSrc, hFileDst, offDst, cbToCopy, fFlags, pBufState, pcbCopied);
+ return rc;
+ }
+ Assert(offThisSrc == offSrc + (int64_t)cbCopied + cbActual);
+ Assert(offThisDst == offDst + (int64_t)cbCopied + cbActual);
+
+ if (cbActual == 0)
+ {
+ if (!pcbCopied)
+ rc = VERR_EOF;
+ break;
+ }
+
+ cbCopied += cbActual;
+ } while (cbCopied < cbToCopy);
+
+ if (pcbCopied)
+ *pcbCopied = cbCopied;
+
+ return rc;
+}
+
+#endif /* __NR_copy_file_range */
+