libgo/go/time/zoneinfo_unix.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 // +build darwin dragonfly freebsd linux 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
  12 package time
  13
  14 import (
  15         "errors"
  16         "runtime"
  17         "syscall"
  18 )
  19
  20 func initTestingZone() {
  21         syscall.Setenv("TZ", "America/Los_Angeles")
  22         initLocal()
  23 }
  24
  25 // Many systems use /usr/share/zoneinfo, Solaris 2 has
  26 // /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ.
  27 var zoneDirs = []string{
  28         "/usr/share/zoneinfo/",
  29         "/usr/share/lib/zoneinfo/",
  30         "/usr/lib/locale/TZ/",
  31         runtime.GOROOT() + "/lib/time/zoneinfo.zip",
  32 }
  33
  34 var origZoneDirs = zoneDirs
  35
  36 func forceZipFileForTesting(zipOnly bool) {
  37         zoneDirs = make([]string, len(origZoneDirs))
  38         copy(zoneDirs, origZoneDirs)
  39         if zipOnly {
  40                 for i := 0; i < len(zoneDirs)-1; i++ {
  41                         zoneDirs[i] = "/XXXNOEXIST"
  42                 }
  43         }
  44 }
  45
  46 func initLocal() {
  47         // consult $TZ to find the time zone to use.
  48         // no $TZ means use the system default /etc/localtime.
  49         // $TZ="" means use UTC.
  50         // $TZ="foo" means use /usr/share/zoneinfo/foo.
  51
  52         tz, ok := syscall.Getenv("TZ")
  53         switch {
  54         case !ok:
  55                 z, err := loadZoneFile("", "/etc/localtime")
  56                 if err == nil {
  57                         localLoc = *z
  58                         localLoc.name = "Local"
  59                         return
  60                 }
  61         case tz != "" && tz != "UTC":
  62                 if z, err := loadLocation(tz); err == nil {
  63                         localLoc = *z
  64                         return
  65                 }
  66         }
  67
  68         // Fall back to UTC.
  69         localLoc.name = "UTC"
  70 }
  71
  72 func loadLocation(name string) (*Location, error) {
  73         for _, zoneDir := range zoneDirs {
  74                 if z, err := loadZoneFile(zoneDir, name); err == nil {
  75                         z.name = name
  76                         return z, nil
  77                 }
  78         }
  79         return nil, errors.New("unknown time zone " + name)
  80 }