github.com/westcoastroms/westcoastroms-build@v0.0.0-20190928114312-2350e5a73030/build/soong/cmd/symbol_inject/pe.go (about)

     1  // Copyright 2018 Google Inc. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package main
    16  
    17  import (
    18  	"debug/pe"
    19  	"fmt"
    20  	"io"
    21  	"sort"
    22  	"strings"
    23  )
    24  
    25  func peSymbolsFromFile(r io.ReaderAt) (*File, error) {
    26  	peFile, err := pe.NewFile(r)
    27  	if err != nil {
    28  		return nil, cantParseError{err}
    29  	}
    30  
    31  	return extractPESymbols(peFile)
    32  }
    33  
    34  func extractPESymbols(peFile *pe.File) (*File, error) {
    35  	var prefix string
    36  	if peFile.FileHeader.Machine == pe.IMAGE_FILE_MACHINE_I386 {
    37  		// symbols in win32 exes seem to be prefixed with an underscore
    38  		prefix = "_"
    39  	}
    40  
    41  	symbols := peFile.Symbols
    42  	sort.SliceStable(symbols, func(i, j int) bool {
    43  		if symbols[i].SectionNumber != symbols[j].SectionNumber {
    44  			return symbols[i].SectionNumber < symbols[j].SectionNumber
    45  		}
    46  		return symbols[i].Value < symbols[j].Value
    47  	})
    48  
    49  	file := &File{}
    50  
    51  	for _, section := range peFile.Sections {
    52  		file.Sections = append(file.Sections, &Section{
    53  			Name:   section.Name,
    54  			Addr:   uint64(section.VirtualAddress),
    55  			Offset: uint64(section.Offset),
    56  			Size:   uint64(section.VirtualSize),
    57  		})
    58  	}
    59  
    60  	for _, symbol := range symbols {
    61  		if symbol.SectionNumber > 0 {
    62  			file.Symbols = append(file.Symbols, &Symbol{
    63  				Name: strings.TrimPrefix(symbol.Name, prefix),
    64  				// PE symbol value is the offset of the symbol into the section
    65  				Addr: uint64(symbol.Value),
    66  				// PE symbols don't have size information
    67  				Size:    0,
    68  				Section: file.Sections[symbol.SectionNumber-1],
    69  			})
    70  		}
    71  	}
    72  
    73  	return file, nil
    74  }
    75  
    76  func dumpPESymbols(r io.ReaderAt) error {
    77  	peFile, err := pe.NewFile(r)
    78  	if err != nil {
    79  		return cantParseError{err}
    80  	}
    81  
    82  	fmt.Println("&pe.File{")
    83  	fmt.Println("\tFileHeader: pe.FileHeader{")
    84  	fmt.Printf("\t\tMachine: %#v,\n", peFile.FileHeader.Machine)
    85  	fmt.Println("\t},")
    86  
    87  	fmt.Println("\tSections: []*pe.Section{")
    88  	for _, section := range peFile.Sections {
    89  		fmt.Printf("\t\t&pe.Section{SectionHeader: %#v},\n", section.SectionHeader)
    90  	}
    91  	fmt.Println("\t},")
    92  
    93  	fmt.Println("\tSymbols: []*pe.Symbol{")
    94  	for _, symbol := range peFile.Symbols {
    95  		fmt.Printf("\t\t%#v,\n", symbol)
    96  	}
    97  	fmt.Println("\t},")
    98  
    99  	fmt.Println("}")
   100  
   101  	return nil
   102  }