obj.go

Documentation: github.com/chenzhuoyu/iasm/obj

     1  package obj
     2  
     3  import (
     4      `fmt`
     5      `io`
     6      `os`
     7  )
     8  
     9  // Format represents the saved binary file format.
    10  type Format int
    11  
    12  const (
    13      // ELF indicates it should be saved as an ELF binary.
    14      ELF Format = iota
    15  
    16      // MachO indicates it should be saved as a Mach-O binary.
    17      MachO
    18  )
    19  
    20  var formatTab = [...]func(w io.Writer, code []byte, base uint64, entry uint64) error {
    21      ELF   : nil,
    22      MachO : assembleMachO,
    23  }
    24  
    25  var formatNames = map[Format]string {
    26      ELF   : "ELF",
    27      MachO : "Mach-O",
    28  }
    29  
    30  // String returns the name of a specified format.
    31  func (self Format) String() string {
    32      if v, ok := formatNames[self]; ok {
    33          return v
    34      } else {
    35          return fmt.Sprintf("Format(%d)", self)
    36      }
    37  }
    38  
    39  // Write assembles a binary executable.
    40  func (self Format) Write(w io.Writer, code []byte, base uint64, entry uint64) error {
    41      if self >= 0 && int(self) < len(formatTab) && formatTab[self] != nil {
    42          return formatTab[self](w, code, base, entry)
    43      } else {
    44          return fmt.Errorf("unsupported format: %s", self)
    45      }
    46  }
    47  
    48  // Generate generates a binary executable file from the specified code.
    49  func (self Format) Generate(name string, code []byte, base uint64, entry uint64) error {
    50      var fp *os.File
    51      var err error
    52  
    53      /* create the output file */
    54      if fp, err = os.Create(name); err != nil {
    55          return err
    56      }
    57  
    58      /* generate the code */
    59      if err = self.Write(fp, code, base, entry); err != nil {
    60          _ = fp.Close()
    61          _ = os.Remove(name)
    62          return err
    63      }
    64  
    65      /* close the file and make it executable */
    66      _ = fp.Close()
    67      _ = os.Chmod(name, 0755)
    68      return nil
    69  }
    70
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