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comparison vendor/golang.org/x/sys/unix/sysvshm_unix.go @ 66:787b5ee0289d draft

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Use vendored modules Signed-off-by: Izuru Yakumo <yakumo.izuru@chaotic.ninja>
author yakumo.izuru
date Sun, 23 Jul 2023 13:18:53 +0000
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children 4b79810863f6
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65:6d985efa0f7a 66:787b5ee0289d
1 // Copyright 2021 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 //go:build (darwin && !ios) || linux
6 // +build darwin,!ios linux
7
8 package unix
9
10 import (
11 "unsafe"
12
13 "golang.org/x/sys/internal/unsafeheader"
14 )
15
16 // SysvShmAttach attaches the Sysv shared memory segment associated with the
17 // shared memory identifier id.
18 func SysvShmAttach(id int, addr uintptr, flag int) ([]byte, error) {
19 addr, errno := shmat(id, addr, flag)
20 if errno != nil {
21 return nil, errno
22 }
23
24 // Retrieve the size of the shared memory to enable slice creation
25 var info SysvShmDesc
26
27 _, err := SysvShmCtl(id, IPC_STAT, &info)
28 if err != nil {
29 // release the shared memory if we can't find the size
30
31 // ignoring error from shmdt as there's nothing sensible to return here
32 shmdt(addr)
33 return nil, err
34 }
35
36 // Use unsafe to convert addr into a []byte.
37 // TODO: convert to unsafe.Slice once we can assume Go 1.17
38 var b []byte
39 hdr := (*unsafeheader.Slice)(unsafe.Pointer(&b))
40 hdr.Data = unsafe.Pointer(addr)
41 hdr.Cap = int(info.Segsz)
42 hdr.Len = int(info.Segsz)
43 return b, nil
44 }
45
46 // SysvShmDetach unmaps the shared memory slice returned from SysvShmAttach.
47 //
48 // It is not safe to use the slice after calling this function.
49 func SysvShmDetach(data []byte) error {
50 if len(data) == 0 {
51 return EINVAL
52 }
53
54 return shmdt(uintptr(unsafe.Pointer(&data[0])))
55 }
56
57 // SysvShmGet returns the Sysv shared memory identifier associated with key.
58 // If the IPC_CREAT flag is specified a new segment is created.
59 func SysvShmGet(key, size, flag int) (id int, err error) {
60 return shmget(key, size, flag)
61 }