zoneinfo_unix.go

Documentation: time

		 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 aix || (darwin && !ios) || dragonfly || freebsd || (linux && !android) || netbsd || openbsd || solaris
		 6  // +build aix darwin,!ios dragonfly freebsd linux,!android netbsd openbsd solaris
		 7  
		 8  // Parse "zoneinfo" time zone file.
		 9  // This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.
		10  // See tzfile(5), https://en.wikipedia.org/wiki/Zoneinfo,
		11  // and ftp://munnari.oz.au/pub/oldtz/
		12  
		13  package time
		14  
		15  import (
		16  	"runtime"
		17  	"syscall"
		18  )
		19  
		20  // Many systems use /usr/share/zoneinfo, Solaris 2 has
		21  // /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ.
		22  var zoneSources = []string{
		23  	"/usr/share/zoneinfo/",
		24  	"/usr/share/lib/zoneinfo/",
		25  	"/usr/lib/locale/TZ/",
		26  	runtime.GOROOT() + "/lib/time/zoneinfo.zip",
		27  }
		28  
		29  func initLocal() {
		30  	// consult $TZ to find the time zone to use.
		31  	// no $TZ means use the system default /etc/localtime.
		32  	// $TZ="" means use UTC.
		33  	// $TZ="foo" or $TZ=":foo" if foo is an absolute path, then the file pointed
		34  	// by foo will be used to initialize timezone; otherwise, file
		35  	// /usr/share/zoneinfo/foo will be used.
		36  
		37  	tz, ok := syscall.Getenv("TZ")
		38  	switch {
		39  	case !ok:
		40  		z, err := loadLocation("localtime", []string{"/etc"})
		41  		if err == nil {
		42  			localLoc = *z
		43  			localLoc.name = "Local"
		44  			return
		45  		}
		46  	case tz != "":
		47  		if tz[0] == ':' {
		48  			tz = tz[1:]
		49  		}
		50  		if tz != "" && tz[0] == '/' {
		51  			if z, err := loadLocation(tz, []string{""}); err == nil {
		52  				localLoc = *z
		53  				if tz == "/etc/localtime" {
		54  					localLoc.name = "Local"
		55  				} else {
		56  					localLoc.name = tz
		57  				}
		58  				return
		59  			}
		60  		} else if tz != "" && tz != "UTC" {
		61  			if z, err := loadLocation(tz, zoneSources); err == nil {
		62  				localLoc = *z
		63  				return
		64  			}
		65  		}
		66  	}
		67  
		68  	// Fall back to UTC.
		69  	localLoc.name = "UTC"
		70  }
		71
View as plain text