github.com/bgentry/go@v0.0.0-20150121062915-6cf5a733d54d/src/cmd/internal/objfile/objfile.go (about)

     1  // Copyright 2014 The Go Authors.  All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package objfile implements portable access to OS-specific executable files.
     6  package objfile
     7  
     8  import (
     9  	"debug/gosym"
    10  	"fmt"
    11  	"os"
    12  	"sort"
    13  )
    14  
    15  type rawFile interface {
    16  	symbols() (syms []Sym, err error)
    17  	pcln() (textStart uint64, symtab, pclntab []byte, err error)
    18  	text() (textStart uint64, text []byte, err error)
    19  	goarch() string
    20  }
    21  
    22  // A File is an opened executable file.
    23  type File struct {
    24  	r   *os.File
    25  	raw rawFile
    26  }
    27  
    28  // A Sym is a symbol defined in an executable file.
    29  type Sym struct {
    30  	Name string // symbol name
    31  	Addr uint64 // virtual address of symbol
    32  	Size int64  // size in bytes
    33  	Code rune   // nm code (T for text, D for data, and so on)
    34  	Type string // XXX?
    35  }
    36  
    37  var openers = []func(*os.File) (rawFile, error){
    38  	openElf,
    39  	openGoobj,
    40  	openMacho,
    41  	openPE,
    42  	openPlan9,
    43  }
    44  
    45  // Open opens the named file.
    46  // The caller must call f.Close when the file is no longer needed.
    47  func Open(name string) (*File, error) {
    48  	r, err := os.Open(name)
    49  	if err != nil {
    50  		return nil, err
    51  	}
    52  	for _, try := range openers {
    53  		if raw, err := try(r); err == nil {
    54  			return &File{r, raw}, nil
    55  		}
    56  	}
    57  	r.Close()
    58  	return nil, fmt.Errorf("open %s: unrecognized object file", name)
    59  }
    60  
    61  func (f *File) Close() error {
    62  	return f.r.Close()
    63  }
    64  
    65  func (f *File) Symbols() ([]Sym, error) {
    66  	syms, err := f.raw.symbols()
    67  	if err != nil {
    68  		return nil, err
    69  	}
    70  	sort.Sort(byAddr(syms))
    71  	return syms, nil
    72  }
    73  
    74  type byAddr []Sym
    75  
    76  func (x byAddr) Less(i, j int) bool { return x[i].Addr < x[j].Addr }
    77  func (x byAddr) Len() int           { return len(x) }
    78  func (x byAddr) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
    79  
    80  func (f *File) PCLineTable() (*gosym.Table, error) {
    81  	textStart, symtab, pclntab, err := f.raw.pcln()
    82  	if err != nil {
    83  		return nil, err
    84  	}
    85  	return gosym.NewTable(symtab, gosym.NewLineTable(pclntab, textStart))
    86  }
    87  
    88  func (f *File) Text() (uint64, []byte, error) {
    89  	return f.raw.text()
    90  }
    91  
    92  func (f *File) GOARCH() string {
    93  	return f.raw.goarch()
    94  }