blob: b82850d6b5ba5eefebf8bde463705be4086ae0f7 [file] [log] [blame]
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build !cmd_go_bootstrap
// This is not built when bootstrapping to avoid having go_bootstrap depend on
// debug/elf.
package main
import (
"debug/elf"
"encoding/binary"
"fmt"
"io"
)
func rnd(v int32, r int32) int32 {
if r <= 0 {
return v
}
v += r - 1
c := v % r
if c < 0 {
c += r
}
v -= c
return v
}
func readwithpad(r io.Reader, sz int32) ([]byte, error) {
full := rnd(sz, 4)
data := make([]byte, full)
_, err := io.ReadFull(r, data)
if err != nil {
return nil, err
}
data = data[:sz]
return data, nil
}
func readnote(filename, name string, typ int32) ([]byte, error) {
f, err := elf.Open(filename)
if err != nil {
return nil, err
}
for _, sect := range f.Sections {
if sect.Type != elf.SHT_NOTE {
continue
}
r := sect.Open()
for {
var namesize, descsize, noteType int32
err = binary.Read(r, f.ByteOrder, &namesize)
if err != nil {
if err == io.EOF {
break
}
return nil, fmt.Errorf("read namesize failed:", err)
}
err = binary.Read(r, f.ByteOrder, &descsize)
if err != nil {
return nil, fmt.Errorf("read descsize failed:", err)
}
err = binary.Read(r, f.ByteOrder, &noteType)
if err != nil {
return nil, fmt.Errorf("read type failed:", err)
}
noteName, err := readwithpad(r, namesize)
if err != nil {
return nil, fmt.Errorf("read name failed:", err)
}
desc, err := readwithpad(r, descsize)
if err != nil {
return nil, fmt.Errorf("read desc failed:", err)
}
if name == string(noteName) && typ == noteType {
return desc, nil
}
}
}
return nil, nil
}