44 lines
1.2 KiB
Bash
Executable file
44 lines
1.2 KiB
Bash
Executable file
#!/run/current-system/sw/bin/bash
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# cpu-watchdog - Detect sustained CPU abuse, kill after 5 consecutive violations
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# Runs every minute via systemd timer
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set -euo pipefail
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# NixOS paths
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PATH="/run/current-system/sw/bin:$PATH"
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THRESHOLD=180 # 180% CPU (almost 2 cores)
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MAX_STRIKES=5
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COUNTDIR="/var/lib/cpu-watchdog"
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mkdir -p "$COUNTDIR"
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for homedir in /home/*; do
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user=$(basename "$homedir")
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# Skip if not a real user
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id "$user" &>/dev/null || continue
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# Get total CPU usage for user
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pct=$(ps -u "$user" -o %cpu= 2>/dev/null | awk '{s+=$1}END{print int(s)}' | tr -d '[:space:]' || echo 0)
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pct=${pct:-0}
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[[ "$pct" =~ ^[0-9]+$ ]] || pct=0
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if [ "$pct" -gt "$THRESHOLD" ]; then
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# Increment strike counter
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count=$(cat "$COUNTDIR/$user" 2>/dev/null || echo 0)
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count=$((count + 1))
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echo "$count" > "$COUNTDIR/$user"
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logger -t cpu-watchdog "User $user at ${pct}% CPU (strike $count/$MAX_STRIKES)"
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if [ "$count" -ge "$MAX_STRIKES" ]; then
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killswitch "$user" "sustained CPU abuse (${pct}%)"
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rm -f "$COUNTDIR/$user"
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fi
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else
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# Reset counter if below threshold
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rm -f "$COUNTDIR/$user"
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fi
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done
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