#!/usr/bin/env bash
# go.sh <name> <seconds>  -- create a private network namespace (loopback only, no route),
# run run.sh inside it, then tear the namespace down. Env knobs pass through to run.sh.
export REPRO=${REPRO:-$(cd "$(dirname "$0")" && pwd)}
export RUNS=${RUNS:-$HOME/fd-guard-runs}
OUT=$RUNS/$1; mkdir -p "$OUT"
setsid unshare -rn sh -c "ip link set lo up && echo \$\$ > $OUT/ns.pid && exec sleep infinity" </dev/null >/dev/null 2>&1 &
for _ in 1 2 3 4 5 6 7 8 9 10; do [ -s "$OUT/ns.pid" ] && break; sleep 0.3; done
NSP=$(cat "$OUT/ns.pid")
cp "$REPRO/run.sh" "$OUT/run.sh.snapshot"   # run a frozen copy: editing run.sh cannot disturb a live run
nsenter -t "$NSP" -U -n --preserve-credentials bash "$OUT/run.sh.snapshot" "$@" > "$OUT/go.txt" 2>&1
rc=$?
kill "$NSP" 2>/dev/null
echo "go.sh: run.sh rc=$rc, namespace holder $NSP killed" >> "$OUT/go.txt"