issue10607a.go

     1  // skip
     2  
     3  // Copyright 2015 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // This is built by issue10607.go with a -B option.
     8  // Verify that we have one build-id note with the expected value.
     9  
    10  package main
    11  
    12  import (
    13  	"bytes"
    14  	"debug/elf"
    15  	"fmt"
    16  	"os"
    17  )
    18  
    19  func main() {
    20  	f, err := elf.Open("/proc/self/exe")
    21  	if err != nil {
    22  		if os.IsNotExist(err) {
    23  			return
    24  		}
    25  		fmt.Fprintln(os.Stderr, "opening /proc/self/exe:", err)
    26  		os.Exit(1)
    27  	}
    28  
    29  	c := 0
    30  	fail := false
    31  	for i, s := range f.Sections {
    32  		if s.Type != elf.SHT_NOTE {
    33  			continue
    34  		}
    35  
    36  		d, err := s.Data()
    37  		if err != nil {
    38  			fmt.Fprintf(os.Stderr, "reading data of note section %d: %v\n", i, err)
    39  			continue
    40  		}
    41  
    42  		for len(d) > 0 {
    43  			namesz := f.ByteOrder.Uint32(d)
    44  			descsz := f.ByteOrder.Uint32(d[4:])
    45  			typ := f.ByteOrder.Uint32(d[8:])
    46  
    47  			an := (namesz + 3) &^ 3
    48  			ad := (descsz + 3) &^ 3
    49  
    50  			if int(12+an+ad) > len(d) {
    51  				fmt.Fprintf(os.Stderr, "note section %d too short for header (%d < 12 + align(%d,4) + align(%d,4))\n", i, len(d), namesz, descsz)
    52  				break
    53  			}
    54  
    55  			// 3 == NT_GNU_BUILD_ID
    56  			if typ == 3 && namesz == 4 && bytes.Equal(d[12:16], []byte("GNU\000")) {
    57  				id := string(d[12+an:12+an+descsz])
    58  				if id == "\x12\x34\x56\x78" {
    59  					c++
    60  				} else {
    61  					fmt.Fprintf(os.Stderr, "wrong build ID data: %q\n", id)
    62  					fail = true
    63  				}
    64  			}
    65  
    66  			d = d[12+an+ad:]
    67  		}
    68  	}
    69  
    70  	if c == 0 {
    71  		fmt.Fprintln(os.Stderr, "no build-id note")
    72  		fail = true
    73  	} else if c > 1 {
    74  		fmt.Fprintln(os.Stderr, c, "build-id notes")
    75  		fail = true
    76  	}
    77  
    78  	if fail {
    79  		os.Exit(1)
    80  	}
    81  }
    82
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