github.com/palisadeinc/bor@v0.0.0-20230615125219-ab7196213d15/consensus/ethash/mmap_help_other.go (about)

     1  // Copyright 2021 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  //go:build !linux
    18  // +build !linux
    19  
    20  package ethash
    21  
    22  import (
    23  	"os"
    24  )
    25  
    26  // ensureSize expands the file to the given size. This is to prevent runtime
    27  // errors later on, if the underlying file expands beyond the disk capacity,
    28  // even though it ostensibly is already expanded, but due to being sparse
    29  // does not actually occupy the full declared size on disk.
    30  func ensureSize(f *os.File, size int64) error {
    31  	// On systems which do not support fallocate, we merely truncate it.
    32  	// More robust alternatives  would be to
    33  	// - Use posix_fallocate, or
    34  	// - explicitly fill the file with zeroes.
    35  	return f.Truncate(size)
    36  }