61 lines
1.8 KiB
Go
61 lines
1.8 KiB
Go
// Copyright 2018 Google Inc.
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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 platform
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import (
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"fmt"
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"io/ioutil"
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"strconv"
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"strings"
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"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
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)
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// systemMMapMinAddrSource is the source file.
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const systemMMapMinAddrSource = "/proc/sys/vm/mmap_min_addr"
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// systemMMapMinAddr is the system's minimum map address.
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var systemMMapMinAddr uint64
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// SystemMMapMinAddr returns the minimum system address.
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func SystemMMapMinAddr() usermem.Addr {
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return usermem.Addr(systemMMapMinAddr)
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}
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// MMapMinAddr is a size zero struct that implements MinUserAddress based on
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// the system minimum address. It is suitable for embedding in platforms that
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// rely on the system mmap, and thus require the system minimum.
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type MMapMinAddr struct {
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}
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// MinUserAddress implements platform.MinUserAddresss.
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func (*MMapMinAddr) MinUserAddress() usermem.Addr {
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return SystemMMapMinAddr()
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}
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func init() {
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// Open the source file.
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b, err := ioutil.ReadFile(systemMMapMinAddrSource)
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if err != nil {
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panic(fmt.Sprintf("couldn't open %s: %v", systemMMapMinAddrSource, err))
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}
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// Parse the result.
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systemMMapMinAddr, err = strconv.ParseUint(strings.TrimSpace(string(b)), 10, 64)
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if err != nil {
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panic(fmt.Sprintf("couldn't parse %s from %s: %v", string(b), systemMMapMinAddrSource, err))
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}
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}
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