forked from wrenn/wrenn
The envd port scanner used gopsutil's net.Connections() which walks
/proc/{pid}/fd to enumerate socket inodes. This corrupts Go runtime
semaphore state when the VM is paused mid-operation and restored from
a Firecracker snapshot.
Replace with a direct /proc/net/tcp + /proc/net/tcp6 parser that reads
a single file per address family — no /proc/{pid}/fd walk, no goroutines,
no WaitGroups. Also replace concurrent-map (smap) in the scanner with a
plain sync.RWMutex-protected map, since concurrent-map's Items() spawns
goroutines with a WaitGroup internally, which is equally unsafe across
snapshot boundaries.
Use socket inode instead of PID for the port forwarding map key, since
inode is available directly from /proc/net/tcp without the fd walk.