stain/sunzip repository overview

⁠Synopsis

sunzip is a streaming unzip utility. It will read a .zip file from stdin and decompress its contents into the current directory. Command line options allow specifying a different destination directory, overwriting existing files (normally prevented), and testing or listing the contents of .zip file instead of writing the decompressed files.

sunzip can decompress methods 0 (stored), 8 (deflated), 9 (Deflate64), 10 (DCL imploded), and 12 (bzip2). sunzip handles Zip64 .zip files. It does not handle encrypted .zip files.

⁠Motivation

Most unzip utilities require random access to the .zip file, since they first read the central directory at the end, and then use that to access the entries in the .zip file. Those utilities cannot accept a .zip file on a pipe. sunzip reads and processes the .zip file contents sequentially. The entry information in the central directory is applied to the already decompressed files when the central directory is read.

⁠Installation

Compile and link with zlib, infback9.c and inftree9.c (found in zlib's contrib directory), blast.c (also in contrib), and libbz2. blast.c from zlib 1.2.9 or later must be used.

⁠Example: Debian/Ubuntu

The below example compiles a recent zlib⁠ that is installed to /usr/local/lib - then contrib/blast and contrib/infback9 before finally downloading and compiling sunzip.c.

Modify the URLs below to use different versions.

apt-get -y install build-essential libbz2-dev curl ca-certificates
cd /tmp

curl -L -o zlib.tar.gz https://github.com/madler/zlib/archive/v1.2.11.tar.gz
tar zxfv zlib.tar.gz
mv zlib-* zlib && cd zlib
./configure && make
sudo make install

cd contrib/blast
gcc -O3 -D_LARGEFILE64_SOURCE=1 -DHAVE_HIDDEN  -I .  -I ../../ -c -Wall -Werror -fpic blast.c
cd ../infback9
gcc  -O3 -D_LARGEFILE64_SOURCE=1 -DHAVE_HIDDEN  -I .  -I ../../ -c -Wall -Werror -fpic infback9.c inftree9.c

cd /tmp
curl -L -o sunzip.tar.gz https://github.com/madler/sunzip/archive/v0.4.tar.gz
tar zxfv sunzip.tar.gz
cd sunzip-*
gcc  -O3 -D_LARGEFILE64_SOURCE=1 -DHAVE_HIDDEN \
  -I ../zlib/contrib/infback9 \
  -I ../zlib/contrib/blast \
  -I ../zlib/contrib/bz \
  -I /usr/local/include \
  -L /usr/local/lib \
  -Wl,-rpath=/usr/local/lib \
  -o sunzip \
  ../zlib/zutil.o \
  ../zlib/contrib/blast/blast.o \
  ../zlib/contrib/infback9/infback9.o  \
  ../zlib/contrib/infback9/inftree9.o  \
  sunzip.c -lbz2 -lz

sudo cp sunzip /usr/local/bin
sunzip

⁠Usage

cat any.zip | sunzip

For help, run sunzip without arguments on a terminal:

sunzip 0.4, streaming unzip by Mark Adler
usage: ... | sunzip [-t] [-o] [-p x] [-q[q]] [dir]
       sunzip [-t] [-o] [-p x] [-q[q]] [dir] < infile.zip

	-t: test -- don't write files
	-l: list zip filenames -- don't write files
	-o: overwrite existing files
	-p x: replace parent reference .. with this character
	-q: quiet -- display summary info and errors only
	-qq: really quiet -- display errors only
	dir: subdirectory to create files in (if writing)

⁠Docker

If you have Docker⁠, you can build a Debian-compatible binary using:

docker build -t stain/sunzip .

The above Docker image is also available at Docker Hub⁠:

docker pull stain/sunzip

The Docker image has the /data volume as default working directory where files will be extracted.

The below example extract from a ZIP URL and extracts it into the host /tmp/1 exposed as /data.

URL=https://github.com/madler/sunzip/archive/master.zip
curl --fail -L $URL | docker run -i -v /tmp/1:/data stain/sunzip

Tip: To avoid extracted files owned by root make sure the mapped directory exists and specify the Docker option --user with your UID:

    mkdir /tmp/5
    URL=https://github.com/madler/sunzip/archive/master.zip
    curl --fail -L $URL | docker run --user `id -u` -i -v /tmp/5:/data stain/sunzip
    ls -al /tmp/5

sunzip will decompress to the current directory unless dir is specified.

The sunzip -t option will test decompression and verify crc checksums without writing any files to disk.

The sunzip -l option is equivalent to -t -q -q, but instead of testing decompression will only print the file and directory names as they are encountered in the stream. Note that file names from the local file headers are less reliable than the end-of-file TOC that would otherwise be used, and may include duplicates, deleted and encrypted files.

⁠License

This code is under the zlib license⁠, permitting free commercial use.