5498f8548b
Test: symbol_inject -i a.out -o a.out2 -s symbol -v value Change-Id: I16cd8facbae754f679bef07ab0ba23638286e1d7
66 lines
1.7 KiB
Go
66 lines
1.7 KiB
Go
// Copyright 2018 Google Inc. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package main
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import (
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"debug/macho"
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"fmt"
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"io"
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)
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func findMachoSymbol(r io.ReaderAt, symbolName string) (uint64, uint64, error) {
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machoFile, err := macho.NewFile(r)
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if err != nil {
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return maxUint64, maxUint64, cantParseError{err}
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}
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// TODO(ccross): why?
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symbolName = "_" + symbolName
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for i, symbol := range machoFile.Symtab.Syms {
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if symbol.Sect == 0 {
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continue
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}
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if symbol.Name == symbolName {
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var nextSymbol *macho.Symbol
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if i+1 < len(machoFile.Symtab.Syms) {
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nextSymbol = &machoFile.Symtab.Syms[i+1]
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}
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return calculateMachoSymbolOffset(machoFile, symbol, nextSymbol)
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}
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}
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return maxUint64, maxUint64, fmt.Errorf("symbol not found")
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}
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func calculateMachoSymbolOffset(file *macho.File, symbol macho.Symbol, nextSymbol *macho.Symbol) (uint64, uint64, error) {
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section := file.Sections[symbol.Sect-1]
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var end uint64
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if nextSymbol != nil && nextSymbol.Sect != symbol.Sect {
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nextSymbol = nil
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}
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if nextSymbol != nil {
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end = nextSymbol.Value
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} else {
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end = section.Addr + section.Size
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}
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size := end - symbol.Value - 1
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offset := uint64(section.Offset) + (symbol.Value - section.Addr)
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return offset, size, nil
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}
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