github.com/AndrienkoAleksandr/go@v0.0.19/src/time/zoneinfo_unix.go (about) 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 //go:build unix && !ios && !android 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), https://en.wikipedia.org/wiki/Zoneinfo, 10 // and ftp://munnari.oz.au/pub/oldtz/ 11 12 package time 13 14 import ( 15 "syscall" 16 ) 17 18 // Many systems use /usr/share/zoneinfo, Solaris 2 has 19 // /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ, 20 // NixOS has /etc/zoneinfo. 21 var platformZoneSources = []string{ 22 "/usr/share/zoneinfo/", 23 "/usr/share/lib/zoneinfo/", 24 "/usr/lib/locale/TZ/", 25 "/etc/zoneinfo", 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" or $TZ=":foo" if foo is an absolute path, then the file pointed 33 // by foo will be used to initialize timezone; otherwise, file 34 // /usr/share/zoneinfo/foo will be used. 35 36 tz, ok := syscall.Getenv("TZ") 37 switch { 38 case !ok: 39 z, err := loadLocation("localtime", []string{"/etc"}) 40 if err == nil { 41 localLoc = *z 42 localLoc.name = "Local" 43 return 44 } 45 case tz != "": 46 if tz[0] == ':' { 47 tz = tz[1:] 48 } 49 if tz != "" && tz[0] == '/' { 50 if z, err := loadLocation(tz, []string{""}); err == nil { 51 localLoc = *z 52 if tz == "/etc/localtime" { 53 localLoc.name = "Local" 54 } else { 55 localLoc.name = tz 56 } 57 return 58 } 59 } else if tz != "" && tz != "UTC" { 60 if z, err := loadLocation(tz, platformZoneSources); err == nil { 61 localLoc = *z 62 return 63 } 64 } 65 } 66 67 // Fall back to UTC. 68 localLoc.name = "UTC" 69 }