Add a tool to inject data into an elf, macho, or PE symbol
Test: symbol_inject -i a.out -o a.out2 -s symbol -v value
Change-Id: I16cd8facbae754f679bef07ab0ba23638286e1d7
diff --git a/cmd/symbol_inject/pe.go b/cmd/symbol_inject/pe.go
new file mode 100644
index 0000000..86f6162
--- /dev/null
+++ b/cmd/symbol_inject/pe.go
@@ -0,0 +1,67 @@
+// 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}
+ }
+
+ 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
+}