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| -rw-r--r-- | README.md | 86 |
1 files changed, 37 insertions, 49 deletions
@@ -5,52 +5,40 @@ on embedded devices, live systems or simply as a compressed archive format. Think of it as a .tar.gz that you can mount (or XZ, LZO, LZ4, ZSTD). -As the name suggests, this is not the original user space tooling for -SquashFS, which is currently maintained in parallel elsewhere. After a -long period of silence on the SourceForge site and mailing list, I -attempted to fork the existing code base with the intention to -restructure/clean it up and add many features I personally perceived to -be missing, but I ultimately decided that it would be easier to start -from scratch than to work with the existing code. - -Here are some of the features that primarily distinguish this package from -the squashfs-tools 4.3 (latest recent version at the time this project was -started): - - - A shared library that encapsulates code for accessing SquashFS images, - usable by 3rd party applications. - - Reproducible, deterministic SquashFS images. - - Linux `gen_init_cpio` like file listing for micro managing the - file system contents, permissions, and ownership without having to replicate - the file system (and especially permissions) locally. - - Support for SELinux contexts file (see selabel_file(5)) to generate - SELinux labels. - - Structured and (hopefully) more readable source code that should be better - maintainable in the long run. - - -In addition to that, tools have been added to directly convert a tar archive -into a SquashFS filesystem image and back. This allows for using existing -tools can work on tar archives seamlessly on SquashFS images. - - -The tools in this package have different names, so they can be installed -together with the existing tools: +This project originally started out as a fork of squashfs-tools 4.3, after +encountering some short comings and realizing that there have been no updates +on the SourceForge site or mailing list for a long time. Even before the first +public release, the fork was replaced with a complete re-write after growing +frustrated with the existing code base. For lack of a better name, and because +the original appeared to be unmaintained at the time, the name squashfs-tools-ng +was kept, although the published code base technically never had any connection +to squashfs-tools. + +Maintenance of the original squashfs-tools has since resumed, squashfs-tools +version 4.4 was released and continues to be maintained in parallel. The +utilities provided by squashfs-tools-ng offer alternative tooling and are +intentionally named differently, so both packages can be installed side by +side. + +The actual guts of squashfs-tools-ng are encapsulated in a library with a +generic API designed to make SquashFS available to other applications as an +embeddable, extensible archive format (or to simply read, write or manipulate +SquashFS file systems). + +The utility programs are largely command line wrappers around the library. The +following tools are provided: - `gensquashfs` can be used to produce SquashFS images from `gen_init_cpio` - like file listings or simply pack an input directory. + like file listings or simply pack an input directory. Can use an SELinux + contexts file (see selabel_file(5)) to generate SELinux labels. - `rdsquashfs` can be used to inspect and unpack SquashFS images. - `sqfs2tar` can turn a SquashFS image into a tarball, written to stdout. - `tar2sqfs` can turn a tarball (read from stdin) into a SquashFS image. - `sqfsdiff` can compare the contents of two SquashFS images. - -Most of the actual logic of those tools is implemented in the `libsquashfs` -library that (by default) gets installed on the system along with its header -files, allowing 3rd party applications to use it (e.g. for embedding SquashFS -inside a custom container format without having to implement the SquashFS -part). - +The library and the tools that produce SquashFS images are designed to operate +deterministically. Same input will produce byte-for-byte identical +output. Failure to do so is treated as a critical bug. # Installing @@ -77,6 +65,16 @@ The headers and import libraries to build applications that use libsquashfs are included. For convenience, the pre-compiled, 3rd party dependency libraries also come with headers and import libraries. +# Copyright & License + +In short: libsquashfs is LGPLv3 licensed, the utility programs are GPLv3. + +Some 3rd party source code is included with more permissive licenses, some of +which is actually compiled into libsquashfs. Copyright notices for those must +be included when distributing either source or binaries of squashfs-tools-ng. + +See [COPYING.md](COPYING.md) for more detailed information. + # Getting and Building the Source Code Official release tarballs can be obtained here: @@ -195,13 +193,3 @@ found in the [documentation directory](doc/format.txt), which is based on an online version that can be found here: https://dr-emann.github.io/squashfs/ - -# Copyright & License - -In short: libsquashfs.so is LGPLv3 licensed, the utility programs are GPLv3. - -Some 3rd party source code is included with more permissive licenses, some of -which is actually compiled into libsquashfs. Copyright notices for those must -be included when distributing either source or binaries of squashfs-tools-ng. - -See [COPYING.md](COPYING.md) for copyright and licensing information. |