Source file src/pkg/net/port.go

     1	// Copyright 2009 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// Read system port mappings from /etc/services
     6	
     7	package net
     8	
     9	import (
    10		"os"
    11		"sync"
    12	)
    13	
    14	var services map[string]map[string]int
    15	var servicesError os.Error
    16	var onceReadServices sync.Once
    17	
    18	func readServices() {
    19		services = make(map[string]map[string]int)
    20		var file *file
    21		if file, servicesError = open("/etc/services"); servicesError != nil {
    22			return
    23		}
    24		for line, ok := file.readLine(); ok; line, ok = file.readLine() {
    25			// "http 80/tcp www www-http # World Wide Web HTTP"
    26			if i := byteIndex(line, '#'); i >= 0 {
    27				line = line[0:i]
    28			}
    29			f := getFields(line)
    30			if len(f) < 2 {
    31				continue
    32			}
    33			portnet := f[1] // "tcp/80"
    34			port, j, ok := dtoi(portnet, 0)
    35			if !ok || port <= 0 || j >= len(portnet) || portnet[j] != '/' {
    36				continue
    37			}
    38			netw := portnet[j+1:] // "tcp"
    39			m, ok1 := services[netw]
    40			if !ok1 {
    41				m = make(map[string]int)
    42				services[netw] = m
    43			}
    44			for i := 0; i < len(f); i++ {
    45				if i != 1 { // f[1] was port/net
    46					m[f[i]] = port
    47				}
    48			}
    49		}
    50		file.close()
    51	}
    52	
    53	// goLookupPort is the native Go implementation of LookupPort.
    54	func goLookupPort(network, service string) (port int, err os.Error) {
    55		onceReadServices.Do(readServices)
    56	
    57		switch network {
    58		case "tcp4", "tcp6":
    59			network = "tcp"
    60		case "udp4", "udp6":
    61			network = "udp"
    62		}
    63	
    64		if m, ok := services[network]; ok {
    65			if port, ok = m[service]; ok {
    66				return
    67			}
    68		}
    69		return 0, &AddrError{"unknown port", network + "/" + service}
    70	}
The Go Programming Language

Source file src/pkg/net/port.go
