diff -r db4911b0c721 -r 445e01aede7e vendor/golang.org/x/sys/unix/sysvshm_unix.go --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/vendor/golang.org/x/sys/unix/sysvshm_unix.go Tue Aug 23 22:39:43 2022 +0200 @@ -0,0 +1,61 @@ +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +//go:build (darwin && !ios) || linux +// +build darwin,!ios linux + +package unix + +import ( + "unsafe" + + "golang.org/x/sys/internal/unsafeheader" +) + +// SysvShmAttach attaches the Sysv shared memory segment associated with the +// shared memory identifier id. +func SysvShmAttach(id int, addr uintptr, flag int) ([]byte, error) { + addr, errno := shmat(id, addr, flag) + if errno != nil { + return nil, errno + } + + // Retrieve the size of the shared memory to enable slice creation + var info SysvShmDesc + + _, err := SysvShmCtl(id, IPC_STAT, &info) + if err != nil { + // release the shared memory if we can't find the size + + // ignoring error from shmdt as there's nothing sensible to return here + shmdt(addr) + return nil, err + } + + // Use unsafe to convert addr into a []byte. + // TODO: convert to unsafe.Slice once we can assume Go 1.17 + var b []byte + hdr := (*unsafeheader.Slice)(unsafe.Pointer(&b)) + hdr.Data = unsafe.Pointer(addr) + hdr.Cap = int(info.Segsz) + hdr.Len = int(info.Segsz) + return b, nil +} + +// SysvShmDetach unmaps the shared memory slice returned from SysvShmAttach. +// +// It is not safe to use the slice after calling this function. +func SysvShmDetach(data []byte) error { + if len(data) == 0 { + return EINVAL + } + + return shmdt(uintptr(unsafe.Pointer(&data[0]))) +} + +// SysvShmGet returns the Sysv shared memory identifier associated with key. +// If the IPC_CREAT flag is specified a new segment is created. +func SysvShmGet(key, size, flag int) (id int, err error) { + return shmget(key, size, flag) +}