| // Copyright 2013 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 ELF executables (Linux, FreeBSD, and so on). |
| |
| package objfile |
| |
| import ( |
| "debug/elf" |
| "fmt" |
| "os" |
| ) |
| |
| type elfFile struct { |
| elf *elf.File |
| } |
| |
| func openElf(r *os.File) (rawFile, error) { |
| f, err := elf.NewFile(r) |
| if err != nil { |
| return nil, err |
| } |
| return &elfFile{f}, nil |
| } |
| |
| func (f *elfFile) symbols() ([]Sym, error) { |
| elfSyms, err := f.elf.Symbols() |
| if err != nil { |
| return nil, err |
| } |
| |
| var syms []Sym |
| for _, s := range elfSyms { |
| sym := Sym{Addr: s.Value, Name: s.Name, Size: int64(s.Size), Code: '?'} |
| switch s.Section { |
| case elf.SHN_UNDEF: |
| sym.Code = 'U' |
| case elf.SHN_COMMON: |
| sym.Code = 'B' |
| default: |
| i := int(s.Section) |
| if i < 0 || i >= len(f.elf.Sections) { |
| break |
| } |
| sect := f.elf.Sections[i] |
| switch sect.Flags & (elf.SHF_WRITE | elf.SHF_ALLOC | elf.SHF_EXECINSTR) { |
| case elf.SHF_ALLOC | elf.SHF_EXECINSTR: |
| sym.Code = 'T' |
| case elf.SHF_ALLOC: |
| sym.Code = 'R' |
| case elf.SHF_ALLOC | elf.SHF_WRITE: |
| sym.Code = 'D' |
| } |
| } |
| if elf.ST_BIND(s.Info) == elf.STB_LOCAL { |
| sym.Code += 'a' - 'A' |
| } |
| syms = append(syms, sym) |
| } |
| |
| return syms, nil |
| } |
| |
| func (f *elfFile) pcln() (textStart uint64, symtab, pclntab []byte, err error) { |
| if sect := f.elf.Section(".text"); sect != nil { |
| textStart = sect.Addr |
| } |
| if sect := f.elf.Section(".gosymtab"); sect != nil { |
| if symtab, err = sect.Data(); err != nil { |
| return 0, nil, nil, err |
| } |
| } |
| if sect := f.elf.Section(".gopclntab"); sect != nil { |
| if pclntab, err = sect.Data(); err != nil { |
| return 0, nil, nil, err |
| } |
| } |
| return textStart, symtab, pclntab, nil |
| } |
| |
| func (f *elfFile) text() (textStart uint64, text []byte, err error) { |
| sect := f.elf.Section(".text") |
| if sect == nil { |
| return 0, nil, fmt.Errorf("text section not found") |
| } |
| textStart = sect.Addr |
| text, err = sect.Data() |
| return |
| } |
| |
| func (f *elfFile) goarch() string { |
| switch f.elf.Machine { |
| case elf.EM_386: |
| return "386" |
| case elf.EM_X86_64: |
| return "amd64" |
| case elf.EM_ARM: |
| return "arm" |
| case elf.EM_PPC64: |
| return "power64" |
| } |
| return "" |
| } |