Consume inotify watches

consume_inotify.sh

#!/bin/bash

TARGET_PERCENT=${1:-60}
WATCH_LIMIT=$(cat /proc/sys/fs/inotify/max_user_watches)
TARGET_WATCHES=$((WATCH_LIMIT * TARGET_PERCENT / 100))

echo "==================================="
echo "Inotify Watch Consumer (Fixed)"
echo "==================================="
echo "System limit: $WATCH_LIMIT watches"
echo "Target: ${TARGET_PERCENT}% ($TARGET_WATCHES watches)"
echo ""

WORK_DIR=$(mktemp -d /tmp/inotify-test-XXXXXX)
echo "Creating test files in $WORK_DIR"

cleanup() {
    echo -e "\n\nCleaning up..."
    if [[ -n "$INOTIFY_PIDS" ]]; then
        kill $INOTIFY_PIDS 2>/dev/null
        wait $INOTIFY_PIDS 2>/dev/null
    fi
    rm -rf "$WORK_DIR"
    echo "Cleanup complete"
    exit 0
}

trap cleanup EXIT INT TERM

mkdir -p "$WORK_DIR"
FILES_NEEDED=$TARGET_WATCHES

echo "Creating $FILES_NEEDED files..."
for ((i=1; i<=FILES_NEEDED; i++)); do
    if ((i % 1000 == 0)); then
        echo "  Created $i/$FILES_NEEDED files ($(( i * 100 / FILES_NEEDED ))%)..."
    fi
    
    SUBDIR="$WORK_DIR/dir_$((i / 100))"
    mkdir -p "$SUBDIR"
    touch "$SUBDIR/file_$i"
done

echo -e "\nEstablishing inotify watches on individual files..."

if ! command -v inotifywait &> /dev/null; then
    echo "ERROR: inotifywait not found. Installing inotify-tools..."
    
    if command -v apt-get &> /dev/null; then
        apt-get update && apt-get install -y inotify-tools
    elif command -v yum &> /dev/null; then
        yum install -y inotify-tools
    elif command -v apk &> /dev/null; then
        apk add --no-cache inotify-tools
    else
        echo "Cannot install inotify-tools. Please install manually."
        exit 1
    fi
fi

INOTIFY_PIDS=""
BATCH_SIZE=1000
BATCH_NUM=0

for ((start=1; start<=FILES_NEEDED; start+=BATCH_SIZE)); do
    end=$((start + BATCH_SIZE - 1))
    if ((end > FILES_NEEDED)); then
        end=$FILES_NEEDED
    fi
    
    echo "  Setting watches on files $start-$end..."
    
    FILE_LIST=""
    for ((i=start; i<=end; i++)); do
        SUBDIR="$WORK_DIR/dir_$((i / 100))"
        FILE_LIST="$FILE_LIST $SUBDIR/file_$i"
    done
    
    inotifywait -m -q -e modify $FILE_LIST > /dev/null 2>&1 &
    INOTIFY_PIDS="$INOTIFY_PIDS $!"
    
    BATCH_NUM=$((BATCH_NUM + 1))
    
    sleep 0.1
done

sleep 3

get_current_watches() {
    local count=0
    for pid in /proc/[0-9]*; do
        [[ -d "$pid/fd" ]] || continue
        for fd in "$pid"/fd/*; do
            [[ -e "$fd" ]] || continue
            link=$(readlink "$fd" 2>/dev/null)
            if [[ "$link" == "anon_inode:inotify" ]]; then
                fdinfo="${fd/\/fd\//\/fdinfo\/}"
                if [[ -r "$fdinfo" ]]; then
                    watches=$(grep -c "^inotify" "$fdinfo" 2>/dev/null || echo 0)
                    count=$((count + watches))
                fi
            fi
        done
    done
    echo $count
}

CURRENT_WATCHES=$(get_current_watches)
USAGE_PERCENT=$(awk "BEGIN {printf \"%.1f\", $CURRENT_WATCHES * 100 / $WATCH_LIMIT}")

echo ""
echo "==================================="
echo "✓ Inotify watches established!"
echo "==================================="
echo "Current system-wide usage:"
echo "  Total watches: $CURRENT_WATCHES"
echo "  Usage: ${USAGE_PERCENT}%"
echo "  Active inotifywait processes: $(echo $INOTIFY_PIDS | wc -w)"
echo ""
echo "This container should trigger your killer if usage >60%"
echo ""
echo "Press Ctrl+C to release watches and exit"
echo ""

while true; do
    CURRENT=$(get_current_watches)
    PERCENT=$(awk "BEGIN {printf \"%.1f\", $CURRENT * 100 / $WATCH_LIMIT}")
    echo "[$(date '+%H:%M:%S')] Current usage: $CURRENT watches (${PERCENT}%)"
    sleep 10
done