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// +build darwin,386 darwin,amd64 dragonfly freebsd linux,!android nacl netbsd openbsd solaris 6 7// Parse "zoneinfo" time zone file. 8// This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others. 9// See tzfile(5), http://en.wikipedia.org/wiki/Zoneinfo, 10// and ftp://munnari.oz.au/pub/oldtz/ 11 12package time 13 14import ( 15 "errors" 16 "runtime" 17 "syscall" 18) 19 20func initTestingZone() { 21 z, err := loadZoneFile(runtime.GOROOT()+"/lib/time/zoneinfo.zip", "America/Los_Angeles") 22 if err != nil { 23 panic("cannot load America/Los_Angeles for testing: " + err.Error()) 24 } 25 z.name = "Local" 26 localLoc = *z 27} 28 29// Many systems use /usr/share/zoneinfo, Solaris 2 has 30// /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ. 31var zoneDirs = []string{ 32 "/usr/share/zoneinfo/", 33 "/usr/share/lib/zoneinfo/", 34 "/usr/lib/locale/TZ/", 35 runtime.GOROOT() + "/lib/time/zoneinfo.zip", 36} 37 38var origZoneDirs = zoneDirs 39 40func forceZipFileForTesting(zipOnly bool) { 41 zoneDirs = make([]string, len(origZoneDirs)) 42 copy(zoneDirs, origZoneDirs) 43 if zipOnly { 44 for i := 0; i < len(zoneDirs)-1; i++ { 45 zoneDirs[i] = "/XXXNOEXIST" 46 } 47 } 48} 49 50func initLocal() { 51 // consult $TZ to find the time zone to use. 52 // no $TZ means use the system default /etc/localtime. 53 // $TZ="" means use UTC. 54 // $TZ="foo" means use /usr/share/zoneinfo/foo. 55 56 tz, ok := syscall.Getenv("TZ") 57 switch { 58 case !ok: 59 z, err := loadZoneFile("", "/etc/localtime") 60 if err == nil { 61 localLoc = *z 62 localLoc.name = "Local" 63 return 64 } 65 case tz != "" && tz != "UTC": 66 if z, err := loadLocation(tz); err == nil { 67 localLoc = *z 68 return 69 } 70 } 71 72 // Fall back to UTC. 73 localLoc.name = "UTC" 74} 75 76func loadLocation(name string) (*Location, error) { 77 var firstErr error 78 for _, zoneDir := range zoneDirs { 79 if z, err := loadZoneFile(zoneDir, name); err == nil { 80 z.name = name 81 return z, nil 82 } else if firstErr == nil && !isNotExist(err) { 83 firstErr = err 84 } 85 } 86 if firstErr != nil { 87 return nil, firstErr 88 } 89 return nil, errors.New("unknown time zone " + name) 90} 91