/usr/share/gocode/src/github.com/influxdata/influxdb/services/httpd/listen.go is in golang-github-influxdb-influxdb-dev 1.1.1+dfsg1-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 | package httpd
import (
"net"
"sync"
)
// LimitListener returns a Listener that accepts at most n simultaneous
// connections from the provided Listener and will drop extra connections.
func LimitListener(l net.Listener, n int) net.Listener {
return &limitListener{Listener: l, sem: make(chan struct{}, n)}
}
// limitListener is a listener that limits the number of active connections
// at any given time.
type limitListener struct {
net.Listener
sem chan struct{}
}
func (l *limitListener) release() {
<-l.sem
}
func (l *limitListener) Accept() (net.Conn, error) {
for {
c, err := l.Listener.Accept()
if err != nil {
return nil, err
}
select {
case l.sem <- struct{}{}:
return &limitListenerConn{Conn: c, release: l.release}, nil
default:
c.Close()
}
}
}
type limitListenerConn struct {
net.Conn
releaseOnce sync.Once
release func()
}
func (l *limitListenerConn) Close() error {
err := l.Conn.Close()
l.releaseOnce.Do(l.release)
return err
}
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