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 aix 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         "runtime"
  16         "syscall"
  17 )
  18
  19 // Many systems use /usr/share/zoneinfo, Solaris 2 has
  20 // /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ.
  21 var zoneSources = []string{
  22         "/usr/share/zoneinfo/",
  23         "/usr/share/lib/zoneinfo/",
  24         "/usr/lib/locale/TZ/",
  25         runtime.GOROOT() + "/lib/time/zoneinfo.zip",
  26 }
  27
  28 func initLocal() {
  29         // consult $TZ to find the time zone to use.
  30         // no $TZ means use the system default /etc/localtime.
  31         // $TZ="" means use UTC.
  32         // $TZ="foo" means use /usr/share/zoneinfo/foo.
  33
  34         tz, ok := syscall.Getenv("TZ")
  35         switch {
  36         case !ok:
  37                 z, err := loadLocation("localtime", []string{"/etc/"})
  38                 if err == nil {
  39                         localLoc = *z
  40                         localLoc.name = "Local"
  41                         return
  42                 }
  43         case tz != "" && tz != "UTC":
  44                 if z, err := loadLocation(tz, zoneSources); err == nil {
  45                         localLoc = *z
  46                         return
  47                 }
  48         }
  49
  50         // Fall back to UTC.
  51         localLoc.name = "UTC"
  52 }