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// Copyright 2018 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"debug/pe"
"fmt"
"io"
"sort"
)
func findPESymbol(r io.ReaderAt, symbolName string) (uint64, uint64, error) {
peFile, err := pe.NewFile(r)
if err != nil {
return maxUint64, maxUint64, cantParseError{err}
}
if peFile.FileHeader.Machine == pe.IMAGE_FILE_MACHINE_I386 {
// symbols in win32 exes seem to be prefixed with an underscore
symbolName = "_" + symbolName
}
sort.Slice(peFile.Symbols, func(i, j int) bool {
if peFile.Symbols[i].SectionNumber != peFile.Symbols[j].SectionNumber {
return peFile.Symbols[i].SectionNumber < peFile.Symbols[j].SectionNumber
}
return peFile.Symbols[i].Value < peFile.Symbols[j].Value
})
for i, symbol := range peFile.Symbols {
if symbol.Name == symbolName {
var nextSymbol *pe.Symbol
if i+1 < len(peFile.Symbols) {
nextSymbol = peFile.Symbols[i+1]
}
return calculatePESymbolOffset(peFile, symbol, nextSymbol)
}
}
return maxUint64, maxUint64, fmt.Errorf("symbol not found")
}
func calculatePESymbolOffset(file *pe.File, symbol *pe.Symbol, nextSymbol *pe.Symbol) (uint64, uint64, error) {
section := file.Sections[symbol.SectionNumber-1]
var end uint32
if nextSymbol != nil && nextSymbol.SectionNumber != symbol.SectionNumber {
nextSymbol = nil
}
if nextSymbol != nil {
end = nextSymbol.Value
} else {
end = section.Size
}
size := end - symbol.Value - 1
offset := section.Offset + symbol.Value
return uint64(offset), uint64(size), nil
}
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