/* $Id: RTFileSetAllocationSize-linux.cpp $ */
/** @file
 * IPRT - RTFileSetAllocationSize, linux implementation.
 */

/*
 * Copyright (C) 2016-2023 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, in version 3 of the
 * License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <https://www.gnu.org/licenses>.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
 * in the VirtualBox 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.
 *
 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#define LOG_GROUP RTLOGGROUP_FILE
#include <iprt/file.h>
#include "internal/iprt.h"

#include <iprt/assert.h>
#include <iprt/errcore.h>

#include <dlfcn.h>
#include <errno.h>
#include <unistd.h>
#include <sys/fcntl.h>

/**
 * The Linux specific fallocate() method.
 */
typedef int (*PFNLNXFALLOCATE) (int iFd, int fMode, off_t offStart, off_t cb);
/** Flag to specify that the file size should not be extended. */
#define LNX_FALLOC_FL_KEEP_SIZE 1

RTDECL(int) RTFileSetAllocationSize(RTFILE hFile, uint64_t cbSize, uint32_t fFlags)
{
    AssertReturn(hFile != NIL_RTFILE, VERR_INVALID_PARAMETER);
    AssertReturn(!(fFlags & ~RTFILE_ALLOC_SIZE_F_VALID), VERR_INVALID_PARAMETER);
    AssertMsgReturn(sizeof(off_t) >= sizeof(cbSize) ||  RT_HIDWORD(cbSize) == 0,
                    ("64-bit filesize not supported! cbSize=%lld\n", cbSize),
                    VERR_NOT_SUPPORTED);

    int rc;
    PFNLNXFALLOCATE pfnLnxFAllocate = (PFNLNXFALLOCATE)(uintptr_t)dlsym(RTLD_DEFAULT, "fallocate64");
    if (RT_VALID_PTR(pfnLnxFAllocate))
    {
        int fLnxFlags = (fFlags & RTFILE_ALLOC_SIZE_F_KEEP_SIZE) ? LNX_FALLOC_FL_KEEP_SIZE : 0;
        int rcLnx = pfnLnxFAllocate(RTFileToNative(hFile), fLnxFlags, 0, cbSize);
        if (rcLnx == 0)
            rc = VINF_SUCCESS;
        else if (errno == EOPNOTSUPP)
            rc = VERR_NOT_SUPPORTED;
        else
            rc = RTErrConvertFromErrno(errno);
    }
    else
        rc = VERR_NOT_SUPPORTED;

    return rc;
}
RT_EXPORT_SYMBOL(RTFileSetAllocationSize);