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| 3bd1f2 | 1 | // Copyright 2016 Tom Thorogood. All rights reserved. |
| Z | 2 | // Use of this source code is governed by a |
| 3 | // Modified BSD License license that can be found in | |
| 4 | // the LICENSE file. | |
| 5 | ||
| 6 | package shm | |
| 7 | ||
| 8 | import ( | |
| 9 | "golang.org/x/sys/unix" | |
| 10 | "sync/atomic" | |
| 11 | "unsafe" | |
| 12 | ||
| 13 | "github.com/tmthrgd/go-shm" | |
| 14 | ) | |
| 15 | ||
| 16 | func OpenSimplex(name string) (*ReadWriteCloser, error) { | |
| 17 | file, err := shm.Open(name, unix.O_RDWR, 0) | |
| 18 | if err != nil { | |
| 19 | return nil, err | |
| 20 | } | |
| 21 | ||
| 22 | defer file.Close() | |
| 23 | ||
| 24 | data, err := unix.Mmap(int(file.Fd()), 0, sharedHeaderSize, unix.PROT_READ, unix.MAP_SHARED) | |
| 25 | if err != nil { | |
| 26 | return nil, err | |
| 27 | } | |
| 28 | ||
| 29 | shared := (*sharedMem)(unsafe.Pointer(&data[0])) | |
| 30 | ||
| 31 | if atomic.LoadUint32((*uint32)(&shared.Version)) != version { | |
| 32 | return nil, ErrInvalidSharedMemory | |
| 33 | } | |
| 34 | ||
| 35 | blockCount, blockSize := uint64(shared.BlockCount), uint64(shared.BlockSize) | |
| 36 | ||
| 37 | if err = unix.Munmap(data); err != nil { | |
| 38 | return nil, err | |
| 39 | } | |
| 40 | ||
| 41 | size := sharedHeaderSize + (blockHeaderSize+blockSize)*blockCount | |
| 42 | ||
| 43 | data, err = unix.Mmap(int(file.Fd()), 0, int(size), unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED) | |
| 44 | if err != nil { | |
| 45 | return nil, err | |
| 46 | } | |
| 47 | ||
| 48 | shared = (*sharedMem)(unsafe.Pointer(&data[0])) | |
| 49 | return &ReadWriteCloser{ | |
| 50 | name: name, | |
| 51 | ||
| 52 | data: data, | |
| 53 | readShared: shared, | |
| 54 | writeShared: shared, | |
| 55 | size: size, | |
| 56 | fullBlockSize: blockHeaderSize + blockSize, | |
| 57 | ||
| 58 | Flags: (*[len(shared.Flags)]uint32)(unsafe.Pointer(&shared.Flags[0])), | |
| 59 | }, nil | |
| 60 | } | |
| 61 | ||
| 62 | func OpenDuplex(name string) (*ReadWriteCloser, error) { | |
| 63 | file, err := shm.Open(name, unix.O_RDWR, 0) | |
| 64 | if err != nil { | |
| 65 | return nil, err | |
| 66 | } | |
| 67 | ||
| 68 | defer file.Close() | |
| 69 | ||
| 70 | data, err := unix.Mmap(int(file.Fd()), 0, sharedHeaderSize, unix.PROT_READ, unix.MAP_SHARED) | |
| 71 | if err != nil { | |
| 72 | return nil, err | |
| 73 | } | |
| 74 | ||
| 75 | shared := (*sharedMem)(unsafe.Pointer(&data[0])) | |
| 76 | ||
| 77 | if atomic.LoadUint32((*uint32)(&shared.Version)) != version { | |
| 78 | return nil, ErrInvalidSharedMemory | |
| 79 | } | |
| 80 | ||
| 81 | blockCount, blockSize := uint64(shared.BlockCount), uint64(shared.BlockSize) | |
| 82 | ||
| 83 | if err = unix.Munmap(data); err != nil { | |
| 84 | return nil, err | |
| 85 | } | |
| 86 | ||
| 87 | sharedSize := sharedHeaderSize + (blockHeaderSize+blockSize)*blockCount | |
| 88 | size := 2 * sharedSize | |
| 89 | ||
| 90 | data, err = unix.Mmap(int(file.Fd()), 0, int(size), unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED) | |
| 91 | if err != nil { | |
| 92 | return nil, err | |
| 93 | } | |
| 94 | ||
| 95 | writeShared := (*sharedMem)(unsafe.Pointer(&data[0])) | |
| 96 | return &ReadWriteCloser{ | |
| 97 | name: name, | |
| 98 | ||
| 99 | data: data, | |
| 100 | readShared: (*sharedMem)(unsafe.Pointer(&data[sharedSize])), | |
| 101 | writeShared: writeShared, | |
| 102 | size: size, | |
| 103 | fullBlockSize: blockHeaderSize + blockSize, | |
| 104 | ||
| 105 | Flags: (*[len(writeShared.Flags)]uint32)(unsafe.Pointer(&writeShared.Flags[0])), | |
| 106 | }, nil | |
| 107 | } | |
