webcam-toggle-setup


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#!/usr/bin/env bash
# webcam-toggle-setup — Interactive setup for webcam-toggle.
# Lists all connected uvcvideo webcams and lets the user choose which one
# to target.  Saves the selection to /var/lib/webcam-toggle/device.
#
# Must be run as root:  sudo webcam-toggle-setup
#
# Can also be run non-interactively:
#   sudo webcam-toggle-setup --list          Print detected webcams
#   sudo webcam-toggle-setup --device 1-5    Set the target device directly

# --- Hardened PATH --------------------------------------------------------
export PATH="/usr/bin:/bin:/usr/sbin:/sbin"

set -euo pipefail

STATE_DIR="/var/lib/webcam-toggle"
DEVICE_FILE="${STATE_DIR}/device"

mkdir -p "$STATE_DIR"
chmod 0755 "$STATE_DIR"

# ---------------------------------------------------------------------------
# validate_dev_id
# ---------------------------------------------------------------------------
validate_dev_id() {
    local id="$1"
    if [[ ! "$id" =~ ^[0-9]+-[0-9]+(\.[0-9]+)*$ ]]; then
        echo "error: invalid device id: '$id'" >&2
        exit 1
    fi
}

# ---------------------------------------------------------------------------
# get_product_name — read the USB product string for a device.
# ---------------------------------------------------------------------------
get_product_name() {
    local dev_id="$1"
    local product_file="/sys/bus/usb/devices/${dev_id}/product"
    if [ -r "$product_file" ]; then
        cat "$product_file"
    else
        echo "(unknown)"
    fi
}

# ---------------------------------------------------------------------------
# list_webcam_devices — enumerate uvcvideo-bound USB devices (deduplicated).
# ---------------------------------------------------------------------------
list_webcam_devices() {
    local seen="" intf intf_dir intf_name dev_id
    for intf in /sys/bus/usb/drivers/uvcvideo/*/driver; do
        [ -e "$intf" ] || continue
        intf_dir="$(dirname "$intf")"
        intf_name="$(basename "$intf_dir")"
        dev_id="${intf_name%%:*}"
        case "$seen" in
            *"|${dev_id}|"*) continue ;;
        esac
        seen="${seen}|${dev_id}|"
        echo "$dev_id"
    done
}

# ---------------------------------------------------------------------------
# save_device — persist the chosen device id.
# ---------------------------------------------------------------------------
save_device() {
    local dev_id="$1"
    validate_dev_id "$dev_id"
    echo "$dev_id" > "$DEVICE_FILE"
    chmod 0600 "$DEVICE_FILE"
    # Clear stale state so the next toggle reads live status.
    rm -f "${STATE_DIR}/unbound"
    echo "Saved device $dev_id ($(get_product_name "$dev_id")) as the target webcam."
}

# ---------------------------------------------------------------------------
# print_list — display a numbered list of webcams.
# Expects the CAMS array to be populated by the caller.
# ---------------------------------------------------------------------------
print_list() {
    local current=""
    [ -f "$DEVICE_FILE" ] && current="$(cat "$DEVICE_FILE")"

    local i
    for i in "${!CAMS[@]}"; do
        local dev_id="${CAMS[$i]}"
        local name
        name="$(get_product_name "$dev_id")"
        local marker=""
        [ "$dev_id" = "$current" ] && marker=" [current]"
        printf "  %d) %-12s %s%s\n" $((i + 1)) "$dev_id" "$name" "$marker"
    done
}

# ---------------------------------------------------------------------------
# Main
# ---------------------------------------------------------------------------

# Populate CAMS once — all subcommands and interactive mode use this snapshot.
mapfile -t CAMS < <(list_webcam_devices)

case "${1:-}" in
    --list)
        if [ "${#CAMS[@]}" -eq 0 ]; then
            echo "No webcams detected."
            exit 1
        fi
        print_list
        exit
        ;;
    --device)
        if [ -z "${2:-}" ]; then
            echo "usage: webcam-toggle-setup --device <bus-port>" >&2
            exit 1
        fi
        save_device "$2"
        exit
        ;;
    "")
        # Interactive mode — fall through
        ;;
    *)
        echo "usage: webcam-toggle-setup [--list | --device <bus-port>]" >&2
        exit 1
        ;;
esac

# --- Interactive selection ------------------------------------------------
if [ "${#CAMS[@]}" -eq 0 ]; then
    echo "No webcams detected."
    exit 1
fi

echo "Detected webcams:"
print_list
echo ""

if [ "${#CAMS[@]}" -eq 1 ]; then
    save_device "${CAMS[0]}"
    exit
fi

while true; do
    printf "Select the webcam to toggle [1-%d]: " "${#CAMS[@]}"
    read -r choice
    if [[ "$choice" =~ ^[0-9]+$ ]] && [ "$choice" -ge 1 ] && [ "$choice" -le "${#CAMS[@]}" ]; then
        save_device "${CAMS[$((choice - 1))]}"
        exit
    fi
    echo "Invalid selection."
done