github.com/sanprasirt/go@v0.0.0-20170607001320-a027466e4b6d/src/cmd/go/internal/cfg/cfg.go (about)

     1  // Copyright 2017 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  // Package cfg holds configuration shared by multiple parts
     6  // of the go command.
     7  package cfg
     8  
     9  import (
    10  	"fmt"
    11  	"go/build"
    12  	"os"
    13  	"path/filepath"
    14  	"runtime"
    15  
    16  	"cmd/internal/objabi"
    17  )
    18  
    19  // These are general "build flags" used by build and other commands.
    20  var (
    21  	BuildA                 bool   // -a flag
    22  	BuildBuildmode         string // -buildmode flag
    23  	BuildContext           = build.Default
    24  	BuildI                 bool               // -i flag
    25  	BuildLdflags           []string           // -ldflags flag
    26  	BuildLinkshared        bool               // -linkshared flag
    27  	BuildMSan              bool               // -msan flag
    28  	BuildN                 bool               // -n flag
    29  	BuildO                 string             // -o flag
    30  	BuildP                 = runtime.NumCPU() // -p flag
    31  	BuildPkgdir            string             // -pkgdir flag
    32  	BuildRace              bool               // -race flag
    33  	BuildToolexec          []string           // -toolexec flag
    34  	BuildToolchainName     string
    35  	BuildToolchainCompiler func() string
    36  	BuildToolchainLinker   func() string
    37  	BuildV                 bool // -v flag
    38  	BuildWork              bool // -work flag
    39  	BuildX                 bool // -x flag
    40  )
    41  
    42  func init() {
    43  	BuildToolchainCompiler = func() string { return "missing-compiler" }
    44  	BuildToolchainLinker = func() string { return "missing-linker" }
    45  }
    46  
    47  // An EnvVar is an environment variable Name=Value.
    48  type EnvVar struct {
    49  	Name  string
    50  	Value string
    51  }
    52  
    53  // OrigEnv is the original environment of the program at startup.
    54  var OrigEnv []string
    55  
    56  // CmdEnv is the new environment for running go tool commands.
    57  // User binaries (during go test or go run) are run with OrigEnv,
    58  // not CmdEnv.
    59  var CmdEnv []EnvVar
    60  
    61  // Global build parameters (used during package load)
    62  var (
    63  	Goarch    string
    64  	Goos      string
    65  	ExeSuffix string
    66  	Gopath    []string
    67  )
    68  
    69  var (
    70  	GOROOT    = findGOROOT()
    71  	GOBIN     = os.Getenv("GOBIN")
    72  	GOROOTbin = filepath.Join(GOROOT, "bin")
    73  	GOROOTpkg = filepath.Join(GOROOT, "pkg")
    74  	GOROOTsrc = filepath.Join(GOROOT, "src")
    75  
    76  	// Used in envcmd.MkEnv and build ID computations.
    77  	GOARM = fmt.Sprint(objabi.GOARM)
    78  	GO386 = objabi.GO386
    79  )
    80  
    81  func findGOROOT() string {
    82  	if env := os.Getenv("GOROOT"); env != "" {
    83  		return filepath.Clean(env)
    84  	}
    85  	exe, err := os.Executable()
    86  	if err == nil {
    87  		exe, err = filepath.Abs(exe)
    88  		if err == nil {
    89  			if dir := filepath.Join(exe, "../.."); isGOROOT(dir) {
    90  				return dir
    91  			}
    92  			exe, err = filepath.EvalSymlinks(exe)
    93  			if err == nil {
    94  				if dir := filepath.Join(exe, "../.."); isGOROOT(dir) {
    95  					return dir
    96  				}
    97  			}
    98  		}
    99  	}
   100  	return filepath.Clean(runtime.GOROOT())
   101  }
   102  
   103  // isGOROOT reports whether path looks like a GOROOT.
   104  //
   105  // It does this by looking for the path/pkg/tool directory,
   106  // which is necessary for useful operation of the cmd/go tool,
   107  // and is not typically present in a GOPATH.
   108  func isGOROOT(path string) bool {
   109  	stat, err := os.Stat(filepath.Join(path, "pkg", "tool"))
   110  	if err != nil {
   111  		return false
   112  	}
   113  	return stat.IsDir()
   114  }