File size: 4,274 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 | // 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.
// Package objfile implements portable access to OS-specific executable files.
package objfile
import (
"cmd/internal/archive"
"cmp"
"debug/dwarf"
"debug/gosym"
"fmt"
"io"
"os"
"slices"
)
type rawFile interface {
symbols() (syms []Sym, err error)
pcln() (textStart uint64, pclntab []byte, err error)
text() (textStart uint64, text []byte, err error)
goarch() string
loadAddress() (uint64, error)
dwarf() (*dwarf.Data, error)
}
// A File is an opened executable file.
type File struct {
r *os.File
entries []*Entry
}
type Entry struct {
name string
raw rawFile
}
// A Sym is a symbol defined in an executable file.
type Sym struct {
Name string // symbol name
Addr uint64 // virtual address of symbol
Size int64 // size in bytes
Code rune // nm code (T for text, D for data, and so on)
Type string // XXX?
Relocs []Reloc // in increasing Addr order
}
type Reloc struct {
Addr uint64 // Address of first byte that reloc applies to.
Size uint64 // Number of bytes
Stringer RelocStringer
}
type RelocStringer interface {
// insnOffset is the offset of the instruction containing the relocation
// from the start of the symbol containing the relocation.
String(insnOffset uint64) string
}
var openers = []func(io.ReaderAt) (rawFile, error){
openElf,
openMacho,
openPE,
openPlan9,
openXcoff,
}
// Open opens the named file.
// The caller must call f.Close when the file is no longer needed.
func Open(name string) (*File, error) {
r, err := os.Open(name)
if err != nil {
return nil, err
}
if f, err := openGoFile(r); err == nil {
return f, nil
} else if _, ok := err.(archive.ErrGoObjOtherVersion); ok {
return nil, fmt.Errorf("open %s: %v", name, err)
}
for _, try := range openers {
if raw, err := try(r); err == nil {
return &File{r, []*Entry{{raw: raw}}}, nil
}
}
r.Close()
return nil, fmt.Errorf("open %s: unrecognized object file", name)
}
func (f *File) Close() error {
return f.r.Close()
}
func (f *File) Entries() []*Entry {
return f.entries
}
func (f *File) Symbols() ([]Sym, error) {
return f.entries[0].Symbols()
}
func (f *File) PCLineTable() (Liner, error) {
return f.entries[0].PCLineTable()
}
func (f *File) Text() (uint64, []byte, error) {
return f.entries[0].Text()
}
func (f *File) GOARCH() string {
return f.entries[0].GOARCH()
}
func (f *File) LoadAddress() (uint64, error) {
return f.entries[0].LoadAddress()
}
func (f *File) DWARF() (*dwarf.Data, error) {
return f.entries[0].DWARF()
}
func (e *Entry) Name() string {
return e.name
}
func (e *Entry) Symbols() ([]Sym, error) {
syms, err := e.raw.symbols()
if err != nil {
return nil, err
}
slices.SortFunc(syms, func(a, b Sym) int {
return cmp.Compare(a.Addr, b.Addr)
})
return syms, nil
}
func (e *Entry) PCLineTable() (Liner, error) {
// If the raw file implements Liner directly, use that.
// Currently, only Go intermediate objects and archives (goobj) use this path.
if pcln, ok := e.raw.(Liner); ok {
return pcln, nil
}
// Otherwise, read the pcln tables and build a Liner out of that.
textStart, pclntab, err := e.raw.pcln()
if err != nil {
return nil, err
}
syms, err := e.raw.symbols()
if err == nil {
for _, s := range syms {
if s.Name == "runtime.text" {
textStart = s.Addr
break
}
}
}
return gosym.NewTable(nil, gosym.NewLineTable(pclntab, textStart))
}
func (e *Entry) Text() (uint64, []byte, error) {
return e.raw.text()
}
func (e *Entry) GOARCH() string {
return e.raw.goarch()
}
// LoadAddress returns the expected load address of the file.
// This differs from the actual load address for a position-independent
// executable.
func (e *Entry) LoadAddress() (uint64, error) {
return e.raw.loadAddress()
}
// DWARF returns DWARF debug data for the file, if any.
// This is for cmd/pprof to locate cgo functions.
func (e *Entry) DWARF() (*dwarf.Data, error) {
return e.raw.dwarf()
}
type Liner interface {
// Given a pc, returns the corresponding file, line, and function data.
// If unknown, returns "",0,nil.
PCToLine(uint64) (string, int, *gosym.Func)
}
|