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2204b6615f
Updates tailscale/tailscale#5793 Fixes golang/go#57336 Change-Id: I4f8128bebcc58f265d447ecaaad2473aafa9131c Reviewed-on: https://go-review.googlesource.com/c/sys/+/458315 Reviewed-by: Michael Pratt <mpratt@google.com> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> Auto-Submit: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: David Chase <drchase@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
55 lines
1.1 KiB
Go
55 lines
1.1 KiB
Go
// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build linux && arm64
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// +build linux,arm64
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package cpu
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import (
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"errors"
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"io"
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"os"
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"strings"
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)
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func readLinuxProcCPUInfo() error {
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f, err := os.Open("/proc/cpuinfo")
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if err != nil {
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return err
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}
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defer f.Close()
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var buf [1 << 10]byte // enough for first CPU
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n, err := io.ReadFull(f, buf[:])
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if err != nil && err != io.ErrUnexpectedEOF {
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return err
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}
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in := string(buf[:n])
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const features = "\nFeatures : "
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i := strings.Index(in, features)
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if i == -1 {
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return errors.New("no CPU features found")
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}
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in = in[i+len(features):]
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if i := strings.Index(in, "\n"); i != -1 {
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in = in[:i]
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}
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m := map[string]*bool{}
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initOptions() // need it early here; it's harmless to call twice
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for _, o := range options {
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m[o.Name] = o.Feature
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}
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// The EVTSTRM field has alias "evstrm" in Go, but Linux calls it "evtstrm".
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m["evtstrm"] = &ARM64.HasEVTSTRM
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for _, f := range strings.Fields(in) {
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if p, ok := m[f]; ok {
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*p = true
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}
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}
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return nil
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}
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