mirror of
https://github.com/netbirdio/gvisor.git
synced 2026-05-22 17:12:49 -07:00
Andrei Vagin
5f4abad306
It is an idea of running codespell as part of our presubmit checks. Before enabling it for new changes, let's fix what it has found. Signed-off-by: Andrei Vagin <avagin@gmail.com>
60 lines
1.7 KiB
Go
60 lines
1.7 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package sharedmem
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import (
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"fmt"
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"reflect"
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"unsafe"
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"golang.org/x/sys/unix"
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"gvisor.dev/gvisor/pkg/atomicbitops"
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"gvisor.dev/gvisor/pkg/memutil"
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)
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// sharedDataPointer converts the shared data slice into a pointer so that it
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// can be used in atomic operations.
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func sharedDataPointer(sharedData []byte) *atomicbitops.Uint32 {
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return (*atomicbitops.Uint32)(unsafe.Pointer(&sharedData[0:4][0]))
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}
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// getBuffer returns a memory region mapped to the full contents of the given
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// file descriptor.
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func getBuffer(fd int) ([]byte, error) {
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var s unix.Stat_t
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if err := unix.Fstat(fd, &s); err != nil {
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return nil, err
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}
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// Check that size doesn't overflow an int.
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if s.Size > int64(^uint(0)>>1) {
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return nil, unix.EDOM
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}
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addr, err := memutil.MapFile(0 /* addr */, uintptr(s.Size), unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED|unix.MAP_FILE, uintptr(fd), 0 /*offset*/)
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if err != nil {
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return nil, fmt.Errorf("failed to map memory for buffer fd: %d, error: %s", fd, err)
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}
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// Use unsafe to convert addr into a []byte.
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var b []byte
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hdr := (*reflect.SliceHeader)(unsafe.Pointer(&b))
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hdr.Data = addr
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hdr.Len = int(s.Size)
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hdr.Cap = int(s.Size)
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return b, nil
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}
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