File size: 3,341 Bytes
e36aeda | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 | // Copyright 2014 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.
// Parsing of Plan 9 a.out executables.
package objfile
import (
"debug/dwarf"
"debug/plan9obj"
"errors"
"fmt"
"io"
"slices"
"sort"
)
var validSymType = map[rune]bool{
'T': true,
't': true,
'D': true,
'd': true,
'B': true,
'b': true,
}
type plan9File struct {
plan9 *plan9obj.File
}
func openPlan9(r io.ReaderAt) (rawFile, error) {
f, err := plan9obj.NewFile(r)
if err != nil {
return nil, err
}
return &plan9File{f}, nil
}
func (f *plan9File) symbols() ([]Sym, error) {
plan9Syms, err := f.plan9.Symbols()
if err != nil {
return nil, err
}
// Build sorted list of addresses of all symbols.
// We infer the size of a symbol by looking at where the next symbol begins.
var addrs []uint64
for _, s := range plan9Syms {
if !validSymType[s.Type] {
continue
}
addrs = append(addrs, s.Value)
}
slices.Sort(addrs)
var syms []Sym
for _, s := range plan9Syms {
if !validSymType[s.Type] {
continue
}
sym := Sym{Addr: s.Value, Name: s.Name, Code: s.Type}
i := sort.Search(len(addrs), func(x int) bool { return addrs[x] > s.Value })
if i < len(addrs) {
sym.Size = int64(addrs[i] - s.Value)
}
syms = append(syms, sym)
}
return syms, nil
}
func (f *plan9File) pcln() (textStart uint64, pclntab []byte, err error) {
textStart = f.plan9.LoadAddress + f.plan9.HdrSize
if pclntab, err = loadPlan9Table(f.plan9, "runtime.pclntab", "runtime.epclntab"); err != nil {
// We didn't find the symbols, so look for the names used in 1.3 and earlier.
// TODO: Remove code looking for the old symbols when we no longer care about 1.3.
var err2 error
if pclntab, err2 = loadPlan9Table(f.plan9, "pclntab", "epclntab"); err2 != nil {
return 0, nil, err
}
}
return textStart, pclntab, nil
}
func (f *plan9File) text() (textStart uint64, text []byte, err error) {
sect := f.plan9.Section("text")
if sect == nil {
return 0, nil, fmt.Errorf("text section not found")
}
textStart = f.plan9.LoadAddress + f.plan9.HdrSize
text, err = sect.Data()
return
}
func findPlan9Symbol(f *plan9obj.File, name string) (*plan9obj.Sym, error) {
syms, err := f.Symbols()
if err != nil {
return nil, err
}
for _, s := range syms {
if s.Name != name {
continue
}
return &s, nil
}
return nil, fmt.Errorf("no %s symbol found", name)
}
func loadPlan9Table(f *plan9obj.File, sname, ename string) ([]byte, error) {
ssym, err := findPlan9Symbol(f, sname)
if err != nil {
return nil, err
}
esym, err := findPlan9Symbol(f, ename)
if err != nil {
return nil, err
}
sect := f.Section("text")
if sect == nil {
return nil, err
}
data, err := sect.Data()
if err != nil {
return nil, err
}
textStart := f.LoadAddress + f.HdrSize
return data[ssym.Value-textStart : esym.Value-textStart], nil
}
func (f *plan9File) goarch() string {
switch f.plan9.Magic {
case plan9obj.Magic386:
return "386"
case plan9obj.MagicAMD64:
return "amd64"
case plan9obj.MagicARM:
return "arm"
}
return ""
}
func (f *plan9File) loadAddress() (uint64, error) {
return 0, fmt.Errorf("unknown load address")
}
func (f *plan9File) dwarf() (*dwarf.Data, error) {
return nil, errors.New("no DWARF data in Plan 9 file")
}
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