From ec623fbde90aed9b3258b9f98bb9f922692744e3 Mon Sep 17 00:00:00 2001 From: Nick Clark Date: Fri, 2 Nov 2018 05:20:31 -0600 Subject: [PATCH] Add README --- README.md | 43 +++++++++++++++++++++++++++++++++++++------ 1 file changed, 37 insertions(+), 6 deletions(-) diff --git a/README.md b/README.md index d938d46..d4ee8f0 100644 --- a/README.md +++ b/README.md @@ -1,9 +1,40 @@ -## PartFS: A FUSE filesystem for accessing part of a file. ## +## Introduction ## -PartFS is an in-development filesystem that lets a user mount a part of a file -as a virtual file, with a user-specified offset and length. +PartFS is a FUSE-based tool for accessing a chunk of a SOURCE file as if it +were a separate file at MOUNTPOINT. It's intended for use in +creating/modifying disk image files. -This allows a user to access a single partition in a larger disk image, as -well as other similar tasks. +Say that SOURCE was a 600000-byte file with the following layout: -PartFS is a work in progress. Expect to see changes added soon. + [Region 1] Bytes 1 to 5000: Bootloader region + [Region 2] Bytes 5001 to 105000: System data + [Region 3] Bytes 105001 to 205000: System Partition + [Region 4] Bytes 205001 to 600000: User Data + +PartFS would allow you to mount any of these regions and access them as if +they were standalone files. In the example given above, the correct mounting +parameters would be: + + partfs SOURCE MOUNTPOINT -o offset=0,sizelimit=5000 + partfs SOURCE MOUNTPOINT -o offset=5000,sizelimit=100000 + partfs SOURCE MOUNTPOINT -o offset=105000,sizelimit=100000 + partfs SOURCE MOUNTPOINT -o offset=205000,sizelimit=395000 + +Note that region 1 could also be mounted with no offset because it starts at +byte 0. Similarly, Region 4 could be mounted with no size-limit because it +goes to the end of the file. + +PartFS is logically similar to a loopback-mounted image under Linux. It has +two key differences though. First, it can be done as an unprivileged user. +And second, it doesn't offer direct access to any filesystems stored +within the mounted image. Consider using with fuse2fs or a similar tool +or unprivileged filesystem access. + +## Current Status ## + +At the time of this writing, PartFS is released as version 1.0 with a functional +test suite. There are no currently-known bugs. Use with pride. + +## License ## + +PartFS is proudly released under GPL 2.0.