setup_v4l2loopback.sh

#!/bin/bash
set -euo pipefail

REPO_DIR="/home/user/Documents/v4l2loopback"
USER_NAME="user"   # replace with your username

# Clone repo if missing
if [ ! -d "$REPO_DIR" ]; then
    sudo -u "$USER_NAME" git clone https://github.com/aab18011/v4l2loopback.git "$REPO_DIR"
fi

cd "$REPO_DIR"

# Get current commit
CURRENT_COMMIT=$(sudo -u "$USER_NAME" git rev-parse HEAD 2>/dev/null || echo "none")

# Fetch latest
sudo -u "$USER_NAME" git fetch origin main

# Get remote commit
REMOTE_COMMIT=$(sudo -u "$USER_NAME" git rev-parse origin/main)

# Determine version (after potential update, but compute now for check)
# Note: Version computed from current code, but if updated, will recompute after reset
VERSION=$(sudo -u "$USER_NAME" git describe --always --dirty 2>/dev/null \
          || sudo -u "$USER_NAME" git describe --always 2>/dev/null \
          || echo snapshot)

# Get current kernel
CURRENT_KERNEL=$(uname -r)

# Check if installed for current kernel
if dkms status | grep -qE "^v4l2loopback,\s*$VERSION,\s*$CURRENT_KERNEL.*: installed$"; then
    INSTALLED=true
else
    INSTALLED=false
fi

if [ "$CURRENT_COMMIT" != "$REMOTE_COMMIT" ] || ! $INSTALLED; then
    # Updates available or not installed, proceed to update/install

    sudo -u "$USER_NAME" git reset --hard origin/main

    # Recompute version after reset
    VERSION=$(sudo -u "$USER_NAME" git describe --always --dirty 2>/dev/null \
              || sudo -u "$USER_NAME" git describe --always 2>/dev/null \
              || echo snapshot)

    echo "Preparing to install v4l2loopback version: $VERSION"

    # --- CLEANUP BROKEN DKMS ENTRIES ---
    for entry in $(dkms status | awk -F, '/^v4l2loopback,/{print $1","$2}' | tr -d ' '); do
        mod="${entry%,*}"
        ver="${entry#*,}"
        SRC_DIR="/var/lib/dkms/$mod/$ver/source"
        if [ ! -f "$SRC_DIR/dkms.conf" ]; then
            echo "Removing broken DKMS entry: $mod $ver"
            dkms remove -m "$mod" -v "$ver" --all || true
            rm -rf "/usr/src/$mod-$ver" "/var/lib/dkms/$mod/$ver"
        fi
    done

    # --- REMOVE OLD VERSIONS ---
    OLD_VERSIONS=$(dkms status | awk -F, '/^v4l2loopback,/{print $2}' | tr -d ' ')
    for ver in $OLD_VERSIONS; do
        if [ "$ver" != "$VERSION" ]; then
            echo "Removing old DKMS version: $ver"
            dkms remove -m v4l2loopback -v "$ver" --all || true
            rm -rf "/usr/src/v4l2loopback-$ver" "/var/lib/dkms/v4l2loopback/$ver"
        fi
    done

    # --- FORCE REMOVE CURRENT VERSION IF EXISTS ---
    dkms remove -m v4l2loopback -v "$VERSION" --all || true
    rm -rf "/var/lib/dkms/v4l2loopback/$VERSION"
    rm -rf "/usr/src/v4l2loopback-$VERSION"

    # --- COPY SOURCES ---
    cp -r . "/usr/src/v4l2loopback-$VERSION"

    # --- ADD / BUILD / INSTALL ---
    dkms add -m v4l2loopback -v "$VERSION"
    dkms build -m v4l2loopback -v "$VERSION"
    dkms install -m v4l2loopback -v "$VERSION" --force

else
    echo "No updates and already installed for current kernel, skipping install."
fi

# --- LOAD MODULE ---
modprobe -r v4l2loopback || true
modprobe v4l2loopback devices=16 exclusive_caps=1 \
    video_nr=$(seq -s, 0 15) \
    card_label=$(printf "'Cam%d'," {0..15} | sed 's/,$//')

echo "v4l2loopback $VERSION loaded."