aboutsummaryrefslogtreecommitdiff
path: root/main.go
diff options
context:
space:
mode:
Diffstat (limited to 'main.go')
-rw-r--r--main.go102
1 files changed, 85 insertions, 17 deletions
diff --git a/main.go b/main.go
index 88ff7c1..a0d217c 100644
--- a/main.go
+++ b/main.go
@@ -2,6 +2,7 @@ package main
import (
"bytes"
+ "compress/flate"
"encoding/json"
"errors"
"fmt"
@@ -9,6 +10,7 @@ import (
"io"
"log"
"os"
+ "path"
"time"
flag "github.com/spf13/pflag"
@@ -16,7 +18,9 @@ import (
func main() {
var zipFilename string
+ var output string
flag.StringVarP(&zipFilename, "filename", "f", "", "filename")
+ flag.StringVarP(&output, "output", "o", "./out/", "output directory")
flag.Parse()
f, err := os.Open(zipFilename)
@@ -27,7 +31,10 @@ func main() {
for {
var sig [4]byte
- if _, err = io.ReadFull(f, sig[:]); err != nil {
+ _, err = io.ReadFull(f, sig[:])
+ if err == io.EOF {
+ break
+ } else if err != nil {
log.Fatal("failed to read signature: ", err)
}
@@ -41,22 +48,47 @@ func main() {
pos, _ := f.Seek(0, io.SeekCurrent)
log.Fatalf("failed to read file header at 0x%x: %s", pos, err)
}
- hdr.HeaderOffset, _ = f.Seek(0, io.SeekCurrent)
+ hdr.Offset, _ = f.Seek(0, io.SeekCurrent)
j, _ := json.MarshalIndent(hdr, "", " ")
- log.Printf("File at 0x%x: %s", hdr.HeaderOffset, string(j))
+ log.Printf("File at 0x%x: %s", hdr.Offset, string(j))
+ hasDD := false
if hdr.Flags&0x08 > 0 {
- log.Printf("Searching for file's end...")
- if err = findAndUseDataDescriptor(&hdr, f); err != nil {
- log.Fatalf("failed to udpate using data descriptor at 0x%x: %s", hdr.HeaderOffset, err)
+ if hdr.CompressedSize == 0 {
+ log.Printf("Searching for file's end...")
+ if err = findAndUseDataDescriptor(&hdr, f); err != nil {
+ log.Fatalf("failed to udpate using data descriptor at 0x%x: %s", hdr.Offset, err)
+ }
}
+ hasDD = true
+ }
+ err := extract(f, &hdr, output)
+ if err != nil {
+ log.Fatalf("failed to extract file: %s", err)
}
- if pos, err := f.Seek(hdr.HeaderOffset+int64(hdr.CompressedSize), io.SeekStart); err != nil {
+ size := int64(hdr.CompressedSize)
+ if size == 0xFFFFFFFF {
+ size = int64(hdr.CompressedSize64)
+ }
+ pos, err := f.Seek(hdr.Offset+size, io.SeekStart)
+ if err != nil {
log.Fatalf("failed to seek to next header, stopped at 0x%x: %s", pos, err)
}
-
- case dataDescriptorSignature:
- io.CopyN(io.Discard, f, 12)
-
+ if hasDD {
+ if _, err = io.ReadFull(f, sig[:]); err != nil {
+ log.Fatal("failed to read DD signature: ", err)
+ }
+ sigb := readBuf(sig[:])
+ signature = sigb.uint32()
+ if signature != dataDescriptorSignature {
+ log.Fatalf("unexpected signature at 0x%x: got %08x", pos, signature)
+ }
+ log.Printf("Skipping data descriptor at 0x%x, zip64=%t...", pos, hdr.zip64)
+ if hdr.zip64 {
+ io.CopyN(io.Discard, f, 20)
+ } else {
+ io.CopyN(io.Discard, f, 12)
+ }
+ }
case directoryHeaderSignature:
var hdr File
if err = readDirectoryHeader(&hdr, f); err != nil {
@@ -109,7 +141,7 @@ func parseFileHeader(f *File, r io.Reader) error {
needUSize := f.UncompressedSize == ^uint32(0)
needCSize := f.CompressedSize == ^uint32(0)
- needHeaderOffset := f.HeaderOffset == int64(^uint32(0))
+ needHeaderOffset := f.Offset == int64(^uint32(0))
// Best effort to find what we need.
// Other zip authors might not even follow the basic format,
@@ -151,7 +183,7 @@ parseExtras:
if len(fieldBuf) < 8 {
return ErrFormat
}
- f.HeaderOffset = int64(fieldBuf.uint64())
+ f.Offset = int64(fieldBuf.uint64())
}
case ntfsExtraID:
if len(fieldBuf) < 4 {
@@ -299,11 +331,11 @@ func findAndUseDataDescriptor(f *File, r io.ReadSeeker) error {
if err := parseDataDescriptor(f, r); err != nil {
return fmt.Errorf("failed to read descriptor : %s", err)
}
- if descriptorPos-int64(f.DescriptorCompressedSize) == f.HeaderOffset+4 {
+ if descriptorPos-int64(f.DescriptorCompressedSize) == f.Offset+4 {
break
} else {
log.Printf("invalid size: expected offset %x (hex) != %x (hex), compsize=%d, size=%d",
- f.HeaderOffset+4, descriptorPos-int64(f.DescriptorCompressedSize), f.DescriptorCompressedSize, f.DescriptorUncompressedSize)
+ f.Offset+4, descriptorPos-int64(f.DescriptorCompressedSize), f.DescriptorCompressedSize, f.DescriptorUncompressedSize)
}
if pos, err = r.Seek(descriptorPos+4, io.SeekStart); err != nil {
return fmt.Errorf("failed to seek to descriptor at 0x%x: %s", pos, err)
@@ -313,8 +345,8 @@ func findAndUseDataDescriptor(f *File, r io.ReadSeeker) error {
}
// bring back at the beginning of the header (due to chunking)
- if _, err := r.Seek(f.HeaderOffset, io.SeekStart); err != nil {
- return fmt.Errorf("failed to seek to beginning at %d: %s", f.HeaderOffset, err)
+ if _, err := r.Seek(f.Offset, io.SeekStart); err != nil {
+ return fmt.Errorf("failed to seek to beginning at %d: %s", f.Offset, err)
}
crc := crc32.NewIEEE()
if _, err := io.CopyN(crc, r, int64(f.DescriptorCompressedSize)); err != nil {
@@ -331,3 +363,39 @@ func findAndUseDataDescriptor(f *File, r io.ReadSeeker) error {
return nil
}
+
+func extract(r io.ReadSeeker, f *File, outputDirectory string) error {
+ dir, base := path.Split(path.Clean(f.Name))
+ directory := path.Join(outputDirectory, dir)
+ err := os.MkdirAll(directory, 0o755)
+ if err != nil {
+ return err
+ }
+
+ w, err := os.OpenFile(path.Join(directory, base), os.O_WRONLY|os.O_CREATE, 0o644)
+ if err != nil {
+ return err
+ }
+ defer w.Close()
+ if _, err := r.Seek(f.Offset, io.SeekStart); err != nil {
+ return err
+ }
+ size := int64(f.UncompressedSize)
+ if size == 0xFFFFFFFF {
+ size = int64(f.UncompressedSize64)
+ }
+ if f.Method == Deflate {
+ fr := flate.NewReader(r)
+ if _, err := io.CopyN(w, fr, size); err != nil {
+ return err
+ }
+ } else if f.Method == Store {
+ if _, err := io.CopyN(w, r, size); err != nil {
+ return err
+ }
+ } else {
+ return errors.New("invalid method")
+ }
+
+ return nil
+}
generated by cgit v1.2.3 (git 2.46.0) at 2026-01-26 21:46:48 +0000