mkfs-sysv

Create SVR4 (System V) filesystem images in Rust.

The on-disk format matches Linux's sysv_fs.h (SVR4 variant), so images can be mounted with the kernel sysv module.

Install

From crates.io:

cargo install mkfs-sysv

This installs a binary called mkfs-sysv. Pre-built binaries for Linux (x86_64 / aarch64), macOS (universal), and Windows are also attached to each GitHub release.

Usage

# Create an empty 4 MB image.
mkfs-sysv out.sysv 4

# Populate from a directory tree (recursive — subdirectories are preserved).
mkfs-sysv -d ./payload out.sysv 4

# Mount on Linux.
sudo mount -o loop,ro -t sysv out.sysv /mnt

Limits

This is a "test image" mkfs:

• 256 inodes total (fixed by layout: 32 inode blocks × 8 inodes/block).
• 14-byte filenames; longer names are truncated.
• Files use direct-only block addressing (10 zone pointers), so the largest file is 10 × 512 = 5 KB.
• Same upper bound applies to directory listings (~320 entries).

License

WTFPL with one extra clause: don't blame me. See LICENSE.