go-deblob

go-deblob.go (2907B)

// This file is part of https://hacktivis.me/git/go-deblob
// Copyright © 2019 Haelwenn (lanodan) Monnier <contact+go-deblob-notice@hacktivis.me>
// SPDX-License-Identifier: BSD-3-Clause
package main
import (
	"bytes"
	"fmt"
	"git.sr.ht/~sircmpwn/getopt"
	"io"
	"log"
	"os"
	"path"
)
var excludes []string
var noop bool
func isBlob(filename string) (result bool) {
	result = false
	// 512 is larger than needed but it's one physical block size
	header := make([]byte, 512)
	file, err := os.Open(filename)
	if err != nil {
		log.Printf("os.Open(%s): %s\n", filename, err)
		return
	}
	defer file.Close()
	_, err = file.Read(header)
	if err != nil && err != io.EOF {
		log.Printf("(%s) os.Read: %s\n", filename, err)
		return
	}
	if bytes.HasPrefix(header, []byte("\x7fELF")) || bytes.HasPrefix(header, []byte("!<arch>\n")) || bytes.HasPrefix(header, []byte("\x55\xAA")) {
		result = true
	}
	return
}
func is_excluded(filename string) bool {
	for _, exclude := range excludes {
		matched, err := path.Match(exclude, filename)
		if err != nil {
			log.Printf("path.Match(%s, %s): %s\n", exclude, filename, err)
			return false
		}
		if matched {
			return true
		}
	}
	return false
}
func checkDir(dirname string, ignoring bool) {
	dirFd, err := os.Open(dirname)
	if err != nil {
		log.Printf("os.Open(%s): %s\n", dirname, err)
		return
	}
	defer dirFd.Close();
	files, err := dirFd.Readdir(0)
	if err != nil {
		log.Printf("(%s) os.Readdir: %v\n", dirname, err)
		return
	}
	for _, file := range files {
		filename := path.Join(dirname, file.Name())
		if !ignoring {
			ignoring = is_excluded(filename)
		}
		if file.IsDir() {
			checkDir(filename, ignoring)
		} else if isBlob(filename) {
			if ignoring {
				fmt.Printf("ignoring: %s\n", filename)
				continue
			}
			if noop {
				fmt.Printf("detected: %s\n", filename)
				continue
			}
			fmt.Printf("removing: %s\n", filename)
			err = os.Remove(filename)
			if err != nil {
				log.Printf("os.Remove(%s): %s\n", filename, err)
			}
		}
	}
}
func usage() {
	println("Usage: go-deblob [-e exclude] [-d workdir]")
	println("	-e	Exclude filepath from removal (defaults to none)")
	println("	-d	Set working directory (defaults to current dir)")
	println("	-n	No actual removal, only scan and log")
	println("See `man 1 go-deblob` for more information.")
}
func main() {
	log.SetFlags(log.Lshortfile)
	workdir := "."
	opts, _, err := getopt.Getopts(os.Args, "e:d:n")
	if err != nil {
		log.Fatal(err)
	}
	for _, opt := range opts {
		switch opt.Option {
		case 'e':
			excludes = append(excludes, string(opt.Value))
		case 'd':
			workdir = opt.Value
		case 'n':
			noop = true
		default:
			usage()
			os.Exit(1)
		}
	}
	err = os.Chdir(workdir)
	if err != nil {
		log.Printf("os.Chdir(%s): %s\n", workdir, err)
		os.Exit(1)
	}
	fmt.Println(":: Checking for blobs")
	checkDir(".", false)
	fmt.Println(":: Done checking for blobs")
}