github.com/zuoyebang/bitalosdb@v1.1.1-0.20240516111551-79a8c4d8ce20/internal/mmap/mmap_unix.go (about)

     1  // Copyright 2021 The Bitalosdb author(hustxrb@163.com) and other contributors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  //go:build darwin || dragonfly || freebsd || linux || openbsd || solaris || netbsd
    16  // +build darwin dragonfly freebsd linux openbsd solaris netbsd
    17  
    18  package mmap
    19  
    20  import (
    21  	"golang.org/x/sys/unix"
    22  )
    23  
    24  func mmapfd(len int, inprot, inflags, fd uintptr, off int64) ([]byte, error) {
    25  	flags := unix.MAP_SHARED
    26  	prot := unix.PROT_READ
    27  	switch {
    28  	case inprot&COPY != 0:
    29  		prot |= unix.PROT_WRITE
    30  		flags = unix.MAP_PRIVATE
    31  	case inprot&RDWR != 0:
    32  		prot |= unix.PROT_WRITE
    33  	}
    34  	if inprot&EXEC != 0 {
    35  		prot |= unix.PROT_EXEC
    36  	}
    37  	if inflags&ANON != 0 {
    38  		flags |= unix.MAP_ANON
    39  	}
    40  
    41  	b, err := unix.Mmap(int(fd), off, len, prot, flags)
    42  	if err != nil {
    43  		return nil, err
    44  	}
    45  	return b, nil
    46  }
    47  
    48  func (m Mbuf) flush() error {
    49  	return unix.Msync([]byte(m), unix.MS_SYNC)
    50  }
    51  
    52  func (m Mbuf) lock() error {
    53  	return unix.Mlock([]byte(m))
    54  }
    55  
    56  func (m Mbuf) unlock() error {
    57  	return unix.Munlock([]byte(m))
    58  }
    59  
    60  func (m Mbuf) unmap() error {
    61  	return unix.Munmap([]byte(m))
    62  }