devwatch

devwatch is a lightweight Linux device observability tool written in Rust.

Think: lsof + htop, but for Linux devices

🧠 Why devwatch?

Linux provides excellent tools for observing systems:

• Processes → top, htop
• Files → lsof

But there is no simple way to answer:

• Which process is using my GPU?
• Who opened /dev/video0?
• Which application is interacting with hardware devices?

devwatch fills this gap.

It bridges:

• /proc → processes

• /dev → device nodes

• /sys → kernel metadata (drivers, subsystems)

• By default, devwatch shows devices currently opened by processes.

• Use --all-devices to inspect all discoverable /dev device nodes.

• So you can clearly understand how software interacts with hardware and kernel subsystems in real time.

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✨ Features

• Process → device mapping via /proc
• /dev → /sys resolution using device numbers
• Subsystem detection (e.g., drm, input, sound)
• Driver detection with parent traversal
• Device classification:
  • physical
  • virtual
  • pseudo
• Cross-platform support:
  • x86 Linux
  • Raspberry Pi
  • Embedded Linux platforms (MPSoC, i.MX, etc.)

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🖥️ Example Output

== drm (3) ==
DEVICE                   PROCESSES                    KIND       DRIVER           DEVNUM         SYSFS
------------------------------------------------------------------------------------------------------------------------
/dev/dri/card1           chrome(3597) [468.2 MB]      physical   i915             226:1          /sys/class/drm/card1
                         code(6088) [241.7 MB]

/dev/dri/renderD128      chrome(3597) [468.2 MB]      physical   i915             226:128        /sys/class/drm/renderD128
                         code(6088) [241.7 MB]

📸 Screenshots

CLI Output

JSON Output

🏗️ Project Structure

src/
├── lib.rs               # Library entry
├── model.rs             # Shared data structures
├── procfs_layer.rs      # Process + FD discovery
├── dev_layer.rs         # /dev extraction & grouping
├── sysfs_layer.rs       # /dev -> /sys resolution
└── bin/
    └── devwatch.rs      # CLI entry point

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🔧 Build

Native build (x86_64)

cargo build --release
cargo run --bin devwatch

Cross compile (ARM64)

cargo build --release --target aarch64-unknown-linux-gnu --bin devwatch

🚀 Install

From source

git clone https://github.com/ravikiranbvn/devwatch
cd devwatch
cargo build --release
./target/release/devwatch

Prebuilt binaries

Download from GitHub Releases:

https://github.com/ravikiranbvn/devwatch/releases
tar -xzf devwatch-linux-x86_64.tar.gz
cd devwatch-linux-x86_64
./devwatch

Usage

# Default view (grouped by subsystem)
devwatch

# Filter by subsystem
devwatch --subsystem drm

# Filter by driver
devwatch --driver i915

# Filter by device name
devwatch --device video

# Show all devices (not just active ones)
devwatch --all-devices

# JSON output
devwatch --json

# Count only
devwatch --count-only

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🎯 Use Cases

• Debugging device access conflicts (e.g., camera, GPU)
• Understanding hardware usage by applications
• Inspecting device behavior on embedded Linux systems
• Exploring Linux internals (/proc, /dev, /sys) in a unified view

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🤝 Contributing

Feedback, issues, and pull requests are welcome.

Open an issue for bugs or feature requests Submit a PR for improvements