// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build aix darwin dragonfly freebsd js,wasm linux netbsd openbsd solaris nacl
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// Read system port mappings from /etc/services
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package net
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import (
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"internal/bytealg"
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"sync"
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)
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var onceReadServices sync.Once
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func readServices() {
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file, err := open("/etc/services")
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if err != nil {
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return
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}
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defer file.close()
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for line, ok := file.readLine(); ok; line, ok = file.readLine() {
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// "http 80/tcp www www-http # World Wide Web HTTP"
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if i := bytealg.IndexByteString(line, '#'); i >= 0 {
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line = line[:i]
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}
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f := getFields(line)
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if len(f) < 2 {
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continue
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}
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portnet := f[1] // "80/tcp"
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port, j, ok := dtoi(portnet)
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if !ok || port <= 0 || j >= len(portnet) || portnet[j] != '/' {
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continue
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}
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netw := portnet[j+1:] // "tcp"
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m, ok1 := services[netw]
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if !ok1 {
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m = make(map[string]int)
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services[netw] = m
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}
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for i := 0; i < len(f); i++ {
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if i != 1 { // f[1] was port/net
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m[f[i]] = port
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}
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}
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}
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}
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// goLookupPort is the native Go implementation of LookupPort.
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func goLookupPort(network, service string) (port int, err error) {
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onceReadServices.Do(readServices)
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return lookupPortMap(network, service)
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}
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