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/* $Id: fileio-at-posix.cpp $ */
/** @file
* IPRT - File I/O, RTFileReadAt and RTFileWriteAt, posix.
*/
/*
* 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 <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include "internal/iprt.h"
#include <iprt/file.h>
#include <iprt/err.h>
#include <iprt/log.h>
RTDECL(int) RTFileReadAt(RTFILE hFile, RTFOFF off, void *pvBuf, size_t cbToRead, size_t *pcbRead)
{
ssize_t cbRead = pread(RTFileToNative(hFile), pvBuf, cbToRead, off);
if (cbRead >= 0)
{
if (pcbRead)
/* caller can handle partial read. */
*pcbRead = cbRead;
else
{
/* Caller expects all to be read. */
while ((ssize_t)cbToRead > cbRead)
{
ssize_t cbReadPart = pread(RTFileToNative(hFile), (char*)pvBuf + cbRead, cbToRead - cbRead, off + cbRead);
if (cbReadPart <= 0)
{
if (cbReadPart == 0)
return VERR_EOF;
return RTErrConvertFromErrno(errno);
}
cbRead += cbReadPart;
}
}
return VINF_SUCCESS;
}
return RTErrConvertFromErrno(errno);
}
RTDECL(int) RTFileWriteAt(RTFILE hFile, RTFOFF off, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
{
ssize_t cbWritten = pwrite(RTFileToNative(hFile), pvBuf, cbToWrite, off);
if (cbWritten >= 0)
{
if (pcbWritten)
/* caller can handle partial write. */
*pcbWritten = cbWritten;
else
{
/* Caller expects all to be write. */
while ((ssize_t)cbToWrite > cbWritten)
{
ssize_t cbWrittenPart = pwrite(RTFileToNative(hFile), (const char *)pvBuf + cbWritten, cbToWrite - cbWritten,
off + cbWritten);
if (cbWrittenPart < 0)
return cbWrittenPart < 0 ? RTErrConvertFromErrno(errno) : VERR_TRY_AGAIN;
cbWritten += cbWrittenPart;
}
}
return VINF_SUCCESS;
}
return RTErrConvertFromErrno(errno);
}
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