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,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
  12 package time
  13
  14 import (
  15         "errors"
  16         "runtime"
  17         "syscall"
  18 )
  19
  20 func initTestingZone() {
  21         z, err := loadLocation("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.
  31 var 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
  38 var origZoneDirs = zoneDirs
  39
  40 func 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
  50 func 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
  76 func 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 }