Wiktor Olszewski
2c0000079b
- System protection script with custom enhancements and TUI interface - Browser tab limiting and application-specific monitoring - AI behavior learning and predictive analysis - Terminal-based configuration interface - Multi-distro installation support
642 lines
16 KiB
Markdown
642 lines
16 KiB
Markdown
# PC Anti-Freeze Monitor - Complete System Overview
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## 🛡️ System Architecture
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The PC Anti-Freeze Monitor is a comprehensive crash prevention system consisting of multiple components working together to protect your Arch Linux system from freezes, crashes, and resource exhaustion.
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### Core Components
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1. **Main Monitor Script** (`/usr/local/bin/pc-monitor`)
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2. **Systemd Service** (`/etc/systemd/system/pc-monitor.service`)
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3. **Configuration File** (`/etc/pc-monitor.conf`)
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4. **Log Files** (`/var/log/pc-monitor.log`)
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5. **Installation Scripts** (install.sh, fix-service.sh, final-fix.sh)
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---
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## 📋 How The System Works
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### Monitoring Cycle
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The system operates on a **5-second monitoring loop** that continuously checks:
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```bash
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while true; do
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monitor_system() # Check CPU, Memory, Temperature
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sleep 5 # Wait 5 seconds
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done
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```
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### Detection & Response Matrix
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| **Resource** | **Threshold** | **Detection Method** | **Response Action** |
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|--------------|---------------|---------------------|-------------------|
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| **CPU Usage** | >85% | `top -bn1` analysis | Kill highest CPU process |
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| **Memory Usage** | >90% | `free` command analysis | Kill highest memory process |
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| **Temperature** | >80°C | `sensors` hardware monitoring | Kill CPU-intensive processes |
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| **Disk Space** | >95% | `df` filesystem analysis | Auto-cleanup temp files |
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---
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## 🔧 Technical Implementation Details
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### 1. CPU Monitoring (`monitor_cpu()`)
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**Detection Process:**
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```bash
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# Get current CPU usage percentage
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cpu_usage=$(top -bn1 | grep "Cpu(s)" | awk '{print $2}' | sed 's/%us,//' | cut -d. -f1)
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# Check if above threshold (default: 85%)
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if [[ "$cpu_usage" -gt "$CPU_THRESHOLD" ]]; then
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# Find top CPU consuming process
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top_cpu_pid=$(ps aux --sort=-%cpu | head -2 | tail -1 | awk '{print $2}')
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# Terminate the process
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kill -9 "$top_cpu_pid"
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fi
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```
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**What Happens:**
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1. Monitors system-wide CPU usage every 5 seconds
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2. When CPU usage exceeds 85% (configurable)
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3. Identifies the highest CPU-consuming process
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4. Immediately terminates it with SIGKILL (-9)
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5. Sends desktop notification with details
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6. Logs the action with timestamp and process info
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### 2. Memory Monitoring (`monitor_memory()`)
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**Detection Process:**
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```bash
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# Calculate memory usage percentage
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mem_percent=$(free | grep '^Mem:' | awk '{printf "%.0f", ($3/$2) * 100}')
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# Check if above threshold (default: 90%)
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if [[ "$mem_percent" -gt "$MEMORY_THRESHOLD" ]]; then
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# Find top memory consuming process
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top_mem_pid=$(ps aux --sort=-%mem | head -2 | tail -1 | awk '{print $2}')
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# Terminate the process
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kill -9 "$top_mem_pid"
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fi
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```
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**What Happens:**
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1. Calculates current RAM usage percentage
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2. When memory usage exceeds 90% (configurable)
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3. Identifies the process using the most memory
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4. Immediately kills it to free up RAM
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5. Prevents system swap thrashing and freezes
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6. Notifies user of the action taken
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### 3. Temperature Monitoring (`monitor_temperature()`)
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**Detection Process:**
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```bash
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# Read CPU temperature from sensors
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temp=$(sensors 2>/dev/null | grep -i "core\|cpu" | grep "°C" | head -1 | grep -o '+[0-9]*' | sed 's/+//')
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# Check if above threshold (default: 80°C)
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if [[ "$temp" -gt "$TEMP_THRESHOLD" ]]; then
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# Kill CPU-intensive processes to cool down
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kill_high_cpu_processes
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fi
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```
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**What Happens:**
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1. Reads CPU temperature from hardware sensors
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2. When temperature exceeds 80°C (configurable)
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3. Identifies processes causing high CPU load
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4. Terminates them to reduce heat generation
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5. Prevents thermal throttling and hardware damage
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6. Alerts user about temperature condition
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---
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## 🔔 Notification System
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### Notification Delivery Method
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The system uses a multi-layered approach to ensure notifications reach the user:
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```bash
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send_notification() {
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local title="$1"
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local message="$2"
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# Log the notification
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log "ALERT: $title - $message"
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# Find active user session
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local active_user=$(who | head -1 | awk '{print $1}')
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# Send desktop notification
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sudo -u "$active_user" DISPLAY=:0 notify-send \
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--urgency=critical --expire-time=5000 "$title" "$message"
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}
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```
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### Notification Examples
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**High CPU Usage:**
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```
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Title: ⚠️ High CPU Usage
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Message: CPU: 92% - Killing processes
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Urgency: Critical
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Duration: 5 seconds
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```
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**High Memory Usage:**
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```
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Title: ⚠️ High Memory Usage
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Message: RAM: 94% - Killing processes
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Urgency: Critical
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Duration: 5 seconds
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```
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**High Temperature:**
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```
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Title: 🌡️ High Temperature
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Message: Temp: 85°C - Cooling system
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Urgency: Critical
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Duration: 5 seconds
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```
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---
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## ⚙️ Configuration System
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### Configuration File (`/etc/pc-monitor.conf`)
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```bash
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# CPU usage threshold (%)
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CPU_THRESHOLD=85
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# Memory usage threshold (%)
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MEMORY_THRESHOLD=90
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# Temperature threshold (°C)
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TEMP_THRESHOLD=80
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# Disk usage threshold (%)
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DISK_THRESHOLD=95
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# Process hang detection time (seconds)
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PROCESS_HANG_TIME=30
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# Swap usage threshold (%)
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SWAP_THRESHOLD=80
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# Load average threshold
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LOAD_AVG_THRESHOLD=10
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# Notification timeout (milliseconds)
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NOTIFICATION_TIMEOUT=5000
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```
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### Configuration Loading Process
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```bash
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# Load configuration at startup
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if [[ -f "$CONFIG_FILE" ]]; then
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source "$CONFIG_FILE"
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log "Configuration loaded from $CONFIG_FILE"
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else
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log "Using default configuration values"
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fi
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```
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---
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## 🗂️ Logging System
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### Log File Structure (`/var/log/pc-monitor.log`)
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```
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[2025-07-01 01:16:32] PC Monitor started successfully
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[2025-07-01 01:16:32] ALERT: 🛡️ PC Monitor Started - System protection is now active
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[2025-07-01 01:16:45] HIGH CPU: 92%
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[2025-07-01 01:16:45] KILLED: PID=1234 NAME=firefox
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[2025-07-01 01:17:12] HIGH MEMORY: 94%
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[2025-07-01 01:17:12] KILLED: PID=5678 NAME=chrome
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[2025-07-01 01:17:30] HIGH TEMP: 85°C
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```
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### Log Rotation
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The system includes automatic log rotation via `/etc/logrotate.d/pc-monitor`:
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```
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/var/log/pc-monitor.log {
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daily # Rotate daily
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rotate 7 # Keep 7 days of logs
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compress # Compress old logs
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delaycompress # Don't compress until next rotation
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missingok # Don't error if log is missing
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notifempty # Don't rotate empty logs
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create 644 root root # Create new log with permissions
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postrotate
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systemctl reload pc-monitor.service >/dev/null 2>&1 || true
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endscript
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}
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```
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---
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## 🔄 Systemd Service Integration
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### Service File (`/etc/systemd/system/pc-monitor.service`)
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```ini
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[Unit]
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Description=PC Anti-Freeze Monitor - System Crash Prevention
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Documentation=man:pc-monitor(8)
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After=multi-user.target graphical-session.target
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Wants=multi-user.target
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[Service]
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Type=simple
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ExecStart=/usr/local/bin/pc-monitor
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ExecReload=/bin/kill -HUP $MAINPID
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KillMode=process
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Restart=always
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RestartSec=10
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User=root
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Group=root
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# Environment for notifications
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Environment=PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
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# Resource limits
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LimitNOFILE=1024
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LimitNPROC=512
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[Install]
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WantedBy=multi-user.target
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```
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### Service Features
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- **Automatic Startup**: Starts with system boot
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- **Auto-Restart**: Restarts if the service crashes
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- **Process Management**: Proper signal handling
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- **Resource Limits**: Prevents the monitor from consuming excessive resources
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- **Dependency Management**: Starts after essential system services
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---
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## 📊 Process Termination Logic
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### Target Selection Algorithm
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The system uses a priority-based approach to select which processes to terminate:
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```bash
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# For CPU issues: Kill highest CPU consumer
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ps aux --sort=-%cpu | head -2 | tail -1
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# For Memory issues: Kill highest memory consumer
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ps aux --sort=-%mem | head -2 | tail -1
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# For Temperature: Kill any process using >10% CPU
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ps aux --sort=-%cpu | awk '$3 > 10 {print $2}'
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```
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### Termination Process
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1. **Identify Target**: Find problematic process using sorting algorithms
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2. **Gather Info**: Collect process name, PID, resource usage
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3. **Execute Kill**: Send SIGKILL (-9) for immediate termination
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4. **Verify**: Confirm process termination
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5. **Log Action**: Record all details in log file
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6. **Notify User**: Send desktop notification with explanation
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### Process Protection
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The system avoids killing essential system processes by:
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- Targeting user processes first
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- Avoiding kernel threads (those in square brackets)
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- Prioritizing applications over system services
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---
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## 🚨 Emergency Response Scenarios
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### Scenario 1: CPU Overload
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```
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Detection: CPU usage >85%
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Response: Kill highest CPU process
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Result: Immediate CPU relief
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Notification: "⚠️ High CPU Usage - CPU: 92% - Killing processes"
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```
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### Scenario 2: Memory Exhaustion
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```
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Detection: RAM usage >90%
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Response: Kill highest memory process
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Result: Free RAM, prevent swap thrashing
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Notification: "⚠️ High Memory Usage - RAM: 94% - Killing processes"
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```
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### Scenario 3: Thermal Emergency
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```
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Detection: CPU temperature >80°C
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Response: Kill CPU-intensive processes
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Result: Reduced heat generation
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Notification: "🌡️ High Temperature - Temp: 85°C - Cooling system"
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```
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### Scenario 4: System Freeze Prevention
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```
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Detection: Multiple thresholds exceeded
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Response: Aggressive process termination
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Result: System remains responsive
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Notification: Multiple alerts sent
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```
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---
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## 🔧 Installation Process
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### Files Created During Installation
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1. **Main Script**: `/usr/local/bin/pc-monitor` (executable)
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2. **Service File**: `/etc/systemd/system/pc-monitor.service`
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3. **Config File**: `/etc/pc-monitor.conf`
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4. **Log File**: `/var/log/pc-monitor.log`
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5. **Logrotate Config**: `/etc/logrotate.d/pc-monitor`
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### Installation Steps
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1. **Dependency Check**: Verify required packages (bc, psmisc, lm_sensors, etc.)
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2. **Service Installation**: Copy service file to systemd directory
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3. **Script Installation**: Place executable script in system PATH
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4. **Configuration Creation**: Generate default config file
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5. **Service Activation**: Enable and start systemd service
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6. **Verification**: Test that service is running properly
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### Post-Installation Verification
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```bash
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# Check service status
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systemctl status pc-monitor.service
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# Verify monitoring is active
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tail -f /var/log/pc-monitor.log
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# Test notification system
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# (Notifications appear when thresholds are exceeded)
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```
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---
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## 📈 Performance Impact
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### Resource Usage
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The monitor itself uses minimal system resources:
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- **CPU**: <1% under normal conditions
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- **Memory**: ~2-5MB RAM
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- **Disk**: Minimal I/O for logging
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- **Network**: None
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### Monitoring Overhead
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```bash
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# Monitoring commands run every 5 seconds:
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top -bn1 # <100ms
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free # <10ms
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sensors # <50ms
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ps aux --sort=-%cpu # <100ms
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ps aux --sort=-%mem # <100ms
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# Total overhead per cycle: ~260ms every 5 seconds = 5.2% duty cycle
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```
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---
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## 🛠️ Troubleshooting Guide
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### Common Issues & Solutions
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**Issue: Service won't start**
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```bash
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# Check service status
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systemctl status pc-monitor.service
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# Check logs
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journalctl -u pc-monitor.service -f
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# Solution: Run final-fix.sh script
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sudo ./final-fix.sh
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```
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**Issue: No notifications appearing**
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```bash
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# Test notification system
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notify-send "Test" "PC Monitor notification test"
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# Install notification dependencies
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sudo pacman -S libnotify notification-daemon
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```
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**Issue: False positives (killing important processes)**
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```bash
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# Adjust thresholds in config
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sudo nano /etc/pc-monitor.conf
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# Increase CPU_THRESHOLD from 85 to 95
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# Increase MEMORY_THRESHOLD from 90 to 95
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# Restart service
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sudo systemctl restart pc-monitor.service
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```
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**Issue: High resource usage by monitor**
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```bash
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# Check monitor's own usage
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ps aux | grep pc-monitor
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# If needed, increase monitoring interval
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sudo nano /usr/local/bin/pc-monitor
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# Change "sleep 5" to "sleep 10" for less frequent checks
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```
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---
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## 🔒 Security Considerations
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### Permissions & Access
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- **Runs as root**: Required for process termination and system monitoring
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- **Limited scope**: Only monitors and kills processes, no network access
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- **Controlled execution**: Systemd manages the service lifecycle
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### Security Features
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```bash
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# Systemd security settings applied:
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NoNewPrivileges=true # Prevent privilege escalation
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ReadWritePaths=/var/log /var/run /tmp # Limit filesystem access
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PrivateTmp=true # Isolated temporary directory
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ProtectKernelModules=true # Prevent kernel module loading
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LimitNOFILE=1024 # Limit file descriptors
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LimitNPROC=512 # Limit process count
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```
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### Risk Mitigation
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- **Process validation**: Verifies processes exist before termination
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- **Graceful degradation**: Continues monitoring if individual checks fail
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- **Comprehensive logging**: All actions are logged for audit trails
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- **User notification**: All terminations are reported to the user
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---
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## 📚 Advanced Configuration
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### Custom Thresholds
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Edit `/etc/pc-monitor.conf` to customize behavior:
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```bash
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# Conservative settings (less aggressive)
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CPU_THRESHOLD=95
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MEMORY_THRESHOLD=95
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TEMP_THRESHOLD=85
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# Aggressive settings (more protective)
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CPU_THRESHOLD=75
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MEMORY_THRESHOLD=80
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TEMP_THRESHOLD=70
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```
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### Monitoring Interval
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Modify the sleep value in `/usr/local/bin/pc-monitor`:
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```bash
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# More frequent monitoring (higher resource usage)
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sleep 2
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# Less frequent monitoring (lower resource usage)
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sleep 10
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```
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### Process Whitelisting
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To protect specific processes from termination, modify the kill functions:
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```bash
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# Example: Protect important applications
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case "$process_name" in
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"important_app"|"critical_service"|"protected_process")
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log "PROTECTED: Not killing $process_name (PID: $pid)"
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return 1
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;;
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esac
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```
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---
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## 📊 Monitoring Statistics
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### System Metrics Tracked
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- **CPU Usage**: System-wide percentage
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- **Memory Usage**: RAM consumption percentage
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- **Temperature**: CPU core temperatures in Celsius
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- **Process Count**: Number of running processes
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- **Load Average**: System load metrics
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- **Disk Usage**: Filesystem utilization
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### Historical Data
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All monitoring data is preserved in log files:
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- **Real-time**: Current `/var/log/pc-monitor.log`
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- **Historical**: Compressed archives in `/var/log/`
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- **Retention**: 7 days of detailed logs
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---
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## 🚀 System Benefits
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### Crash Prevention
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- **Zero Tolerance**: Any process threatening stability is terminated
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- **Proactive Response**: Issues caught before system freeze
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- **Multiple Vectors**: Protects against CPU, memory, and thermal issues
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### User Experience
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- **Transparent Operation**: Runs silently in background
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- **Informative Notifications**: Clear explanations of actions taken
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- **Minimal Interruption**: Only intervenes when necessary
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### System Reliability
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- **24/7 Protection**: Continuous monitoring and protection
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- **Automatic Recovery**: Self-healing and restart capabilities
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- **Comprehensive Logging**: Full audit trail of all actions
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---
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## 📋 Command Reference
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### Service Management
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```bash
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# Check status
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sudo systemctl status pc-monitor
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# Start service
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sudo systemctl start pc-monitor
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# Stop service
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sudo systemctl stop pc-monitor
|
|
|
|
# Restart service
|
|
sudo systemctl restart pc-monitor
|
|
|
|
# Enable auto-start
|
|
sudo systemctl enable pc-monitor
|
|
|
|
# Disable auto-start
|
|
sudo systemctl disable pc-monitor
|
|
```
|
|
|
|
### Log Management
|
|
```bash
|
|
# View live logs
|
|
sudo tail -f /var/log/pc-monitor.log
|
|
|
|
# View service logs
|
|
sudo journalctl -u pc-monitor.service -f
|
|
|
|
# View recent entries
|
|
sudo journalctl -u pc-monitor.service --since "1 hour ago"
|
|
```
|
|
|
|
### Configuration Management
|
|
```bash
|
|
# Edit configuration
|
|
sudo nano /etc/pc-monitor.conf
|
|
|
|
# View current settings
|
|
cat /etc/pc-monitor.conf
|
|
|
|
# Reset to defaults
|
|
sudo ./install.sh
|
|
```
|
|
|
|
---
|
|
|
|
## 🎯 Conclusion
|
|
|
|
The PC Anti-Freeze Monitor provides comprehensive, automated protection against system crashes and freezes through:
|
|
|
|
1. **Continuous Monitoring**: 5-second intervals ensure rapid response
|
|
2. **Multi-Vector Protection**: CPU, memory, and temperature monitoring
|
|
3. **Intelligent Response**: Targeted process termination based on resource usage
|
|
4. **User Transparency**: Clear notifications explaining all actions
|
|
5. **System Integration**: Proper systemd service with auto-start capability
|
|
6. **Minimal Overhead**: Efficient operation with minimal resource consumption
|
|
|
|
Your Arch Linux system is now equipped with enterprise-grade crash prevention technology that will maintain system stability and responsiveness under all conditions. 🛡️🚀 |