add en elf dumper (#7)

.github/workflows/ci.yaml

@@ -39,9 +39,8 @@ jobs:
           go vet .
         if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.21.x'
 
-      - name: Staticcheck
-        uses: dominikh/staticcheck-action@v1.3.0
-        with:
-          version: "2022.1"
-          install-go: false
+      - name: Go vet
+        run: |
+          go install honnef.co/go/tools/cmd/staticcheck@latest
+          staticcheck .
         if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.21.x'

.vscode/launch.json

@@ -10,7 +10,7 @@
             "request": "launch",
             "mode": "debug",
             "program": "${file}",
-            "args": ["dump", "--file-header"]
+            "args": ["dump", "--file-header", "/bin/ls"]
         },
         {
             "name": "Attach to Process",

cmd/elfdump.go

@@ -1,14 +1,54 @@
+// Copyright 2018 Saferwall. All rights reserved.
+// Use of this source code is governed by Apache v2 license
+// license that can be found in the LICENSE file.
+
 package main
 
 import (
+	"flag"
 	"fmt"
+	"os"
+	"strings"
+	"text/tabwriter"
 
 	"github.com/saferwall/elf"
 )
 
-func main() {
+type config struct {
+	wantELFFileHeader bool
+}
+
+var Usage = func() {
+	fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
+	flag.PrintDefaults()
+}
+
+func dumpFileHeader(fileHdr elf.FileHeader) {
+	w := tabwriter.NewWriter(os.Stdout, 1, 1, 3, ' ', tabwriter.AlignRight)
+	fmt.Print("\n\t------[ File Header ]------\n\n")
+	fmt.Fprintf(w, "Magic:\t %v\n", fileHdr.Ident.Magic)
+	fmt.Fprintf(w, "Class:\t %v\n", fileHdr.Ident.Class)
+	fmt.Fprintf(w, "Data:\t %v\n", fileHdr.Ident.Data)
+	fmt.Fprintf(w, "Version:\t %v\n", fileHdr.Ident.Version)
+	fmt.Fprintf(w, "OS/ABI:\t %v\n", fileHdr.Ident.ABIVersion)
+	fmt.Fprintf(w, "Type:\t %v\n", fileHdr.Type)
+	fmt.Fprintf(w, "Machine:\t %v\n", fileHdr.Machine)
+	fmt.Fprintf(w, "Version:\t %v\n", fileHdr.Version)
+	fmt.Fprintf(w, "Entry point address :\t %v\n", fileHdr.Entry)
+	fmt.Fprintf(w, "Start of program headers:\t %v\n", fileHdr.ProgramHeaderOffset)
+	fmt.Fprintf(w, "Start of section headers:\t %v\n", fileHdr.SectionHeaderOffset)
+	fmt.Fprintf(w, "Flags:\t %v\n", fileHdr.Flags)
+	fmt.Fprintf(w, "Size of this header:\t %v\n", fileHdr.Size)
+	fmt.Fprintf(w, "Size of program headers:\t %v\n", fileHdr.ProgramHeaderEntrySize)
+	fmt.Fprintf(w, "Number of program headers:\t %v\n", fileHdr.ProgramHeaderNum)
+	fmt.Fprintf(w, "Size of section headers:\t %v\n", fileHdr.SectionHeaderEntrySize)
+	fmt.Fprintf(w, "Number of section headers:\t %v\n", fileHdr.SectionHeaderNum)
+	fmt.Fprintf(w, "Section header string table index:\t %v\n", fileHdr.SectionHeaderStringIdx)
+	w.Flush()
+}
 
-	p, err := elf.New("/bin/ls")
+func parse(filename string, cfg config) {
+	p, err := elf.New(filename)
 	defer p.CloseFile()
 	if err != nil {
 		panic(err)
@@ -17,9 +57,76 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
-	jsonFile, err := p.DumpRawJSON()
-	if err != nil {
-		panic(err)
+
+	if cfg.wantELFFileHeader {
+		dumpFileHeader(p.F.FileHeader)
+	}
+}
+
+func main() {
+
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, "This is not helpful.\n")
 	}
-	fmt.Println(jsonFile)
+	dumpCmd := flag.NewFlagSet("dump", flag.ExitOnError)
+	dumpELFFileHdr := dumpCmd.Bool("file-header", false, "Display the ELF file header")
+	verCmd := flag.NewFlagSet("version", flag.ExitOnError)
+
+	if len(os.Args) < 2 {
+		showHelp(nil)
+	}
+
+	switch os.Args[1] {
+
+	case "dump":
+		var filename string
+		for _, arg := range os.Args[2:] {
+			if !strings.HasPrefix(arg, "-") {
+				filename = arg
+			}
+		}
+		if len(filename) == 0 {
+			showHelp(dumpCmd)
+		}
+
+		if err := dumpCmd.Parse(os.Args[2:]); err != nil {
+			showHelp(dumpCmd)
+		}
+
+		cfg := config{
+			wantELFFileHeader: *dumpELFFileHdr,
+		}
+
+		parse(filename, cfg)
+
+	case "version":
+		verCmd.Parse(os.Args[2:])
+		fmt.Println("You are using version 0.4.0")
+	default:
+		showHelp(nil)
+	}
+}
+
+func showHelp(cmd *flag.FlagSet) {
+	fmt.Print(
+		`
+			┏┓┏┓┏┓┏┓┳┓┓ ┏┏┓┓ ┓
+			┗┓┣┫┣ ┣ ┣┫┃┃┃┣┫┃ ┃
+			┗┛┛┗┻ ┗┛┛┗┗┻┛┛┗┗┛┗┛
+			┏┓┓ ┏┓  ┏┓┏┓┳┓┏┓┏┓┳┓
+			┣ ┃ ┣   ┃┃┣┫┣┫┗┓┣ ┣┫
+			┗┛┗┛┻   ┣┛┛┗┛┗┗┛┗┛┛┗
+
+
+	An ELF Parser built for speed and malware-analysis in mind.
+	Brought to you by Saferwall (c) 2018 Apache-2.0
+`)
+	if cmd == nil {
+		fmt.Println("\nAvailable sub-commands 'dump' or 'version' subcommands !")
+	} else {
+		fmt.Println("\nUsage: elfdump <option(s)> elf-file(s)\nOptions are:")
+		cmd.PrintDefaults()
+	}
+
+	os.Exit(1)
 }