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https://github.com/golang/go
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7fdb0292a5
Some systems, like Ubuntu, pass --build-id when linking. The effect is to put a note in the output file. This is not useful when generating an object file with the -r option, as it eventually causes multiple build ID notes in the final executable, all but one of which are for tiny portions of the file and are therefore useless. Disable that by passing an explicit --build-id=none when linking with -r on systems that might do this. LGTM=bradfitz R=golang-codereviews, bradfitz CC=golang-codereviews https://golang.org/cl/119460043
78 lines
1.6 KiB
Go
78 lines
1.6 KiB
Go
// Copyright 2014 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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package cgotest
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// Test that we have no more than one build ID. In the past we used
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// to generate a separate build ID for each package using cgo, and the
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// linker concatenated them all. We don't want that--we only want
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// one.
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import (
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"bytes"
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"debug/elf"
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"os"
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"testing"
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)
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func testBuildID(t *testing.T) {
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f, err := elf.Open("/proc/self/exe")
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if err != nil {
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if os.IsNotExist(err) {
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t.Skip("no /proc/self/exe")
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}
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t.Fatalf("opening /proc/self/exe: ", err)
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}
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defer f.Close()
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c := 0
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for i, s := range f.Sections {
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if s.Type != elf.SHT_NOTE {
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continue
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}
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d, err := s.Data()
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if err != nil {
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t.Logf("reading data of note section %d: %v", i, err)
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continue
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}
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for len(d) > 0 {
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// ELF standards differ as to the sizes in
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// note sections. Both the GNU linker and
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// gold always generate 32-bit sizes, so that
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// is what we assume here.
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if len(d) < 12 {
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t.Logf("note section %d too short (%d < 12)", i, len(d))
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continue
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}
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namesz := f.ByteOrder.Uint32(d)
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descsz := f.ByteOrder.Uint32(d[4:])
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typ := f.ByteOrder.Uint32(d[8:])
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an := (namesz + 3) &^ 3
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ad := (descsz + 3) &^ 3
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if int(12+an+ad) > len(d) {
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t.Logf("note section %d too short for header (%d < 12 + align(%d,4) + align(%d,4))", i, len(d), namesz, descsz)
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continue
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}
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// 3 == NT_GNU_BUILD_ID
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if typ == 3 && namesz == 4 && bytes.Equal(d[12:16], []byte("GNU\000")) {
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c++
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}
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d = d[12+an+ad:]
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}
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}
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if c > 1 {
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t.Errorf("found %d build ID notes", c)
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}
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}
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