github.com/goproxy0/go@v0.0.0-20171111080102-49cc0c489d2c/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  	BuildLinkshared        bool               // -linkshared flag
    26  	BuildMSan              bool               // -msan flag
    27  	BuildN                 bool               // -n flag
    28  	BuildO                 string             // -o flag
    29  	BuildP                 = runtime.NumCPU() // -p flag
    30  	BuildPkgdir            string             // -pkgdir flag
    31  	BuildRace              bool               // -race flag
    32  	BuildToolexec          []string           // -toolexec flag
    33  	BuildToolchainName     string
    34  	BuildToolchainCompiler func() string
    35  	BuildToolchainLinker   func() string
    36  	BuildV                 bool // -v flag
    37  	BuildWork              bool // -work flag
    38  	BuildX                 bool // -x flag
    39  
    40  	CmdName string // "build", "install", "list", etc.
    41  
    42  	DebugActiongraph string // -debug-actiongraph flag (undocumented, unstable)
    43  )
    44  
    45  func init() {
    46  	BuildToolchainCompiler = func() string { return "missing-compiler" }
    47  	BuildToolchainLinker = func() string { return "missing-linker" }
    48  }
    49  
    50  // An EnvVar is an environment variable Name=Value.
    51  type EnvVar struct {
    52  	Name  string
    53  	Value string
    54  }
    55  
    56  // OrigEnv is the original environment of the program at startup.
    57  var OrigEnv []string
    58  
    59  // CmdEnv is the new environment for running go tool commands.
    60  // User binaries (during go test or go run) are run with OrigEnv,
    61  // not CmdEnv.
    62  var CmdEnv []EnvVar
    63  
    64  // Global build parameters (used during package load)
    65  var (
    66  	Goarch    = BuildContext.GOARCH
    67  	Goos      = BuildContext.GOOS
    68  	ExeSuffix string
    69  	Gopath    = filepath.SplitList(BuildContext.GOPATH)
    70  )
    71  
    72  func init() {
    73  	if Goos == "windows" {
    74  		ExeSuffix = ".exe"
    75  	}
    76  }
    77  
    78  var (
    79  	GOROOT    = findGOROOT()
    80  	GOBIN     = os.Getenv("GOBIN")
    81  	GOROOTbin = filepath.Join(GOROOT, "bin")
    82  	GOROOTpkg = filepath.Join(GOROOT, "pkg")
    83  	GOROOTsrc = filepath.Join(GOROOT, "src")
    84  
    85  	// Used in envcmd.MkEnv and build ID computations.
    86  	GOARM = fmt.Sprint(objabi.GOARM)
    87  	GO386 = objabi.GO386
    88  )
    89  
    90  // Update build context to use our computed GOROOT.
    91  func init() {
    92  	BuildContext.GOROOT = GOROOT
    93  	// Note that we must use runtime.GOOS and runtime.GOARCH here,
    94  	// as the tool directory does not move based on environment variables.
    95  	// This matches the initialization of ToolDir in go/build,
    96  	// except for using GOROOT rather than runtime.GOROOT().
    97  	build.ToolDir = filepath.Join(GOROOT, "pkg/tool/"+runtime.GOOS+"_"+runtime.GOARCH)
    98  }
    99  
   100  func findGOROOT() string {
   101  	if env := os.Getenv("GOROOT"); env != "" {
   102  		return filepath.Clean(env)
   103  	}
   104  	def := filepath.Clean(runtime.GOROOT())
   105  	exe, err := os.Executable()
   106  	if err == nil {
   107  		exe, err = filepath.Abs(exe)
   108  		if err == nil {
   109  			if dir := filepath.Join(exe, "../.."); isGOROOT(dir) {
   110  				// If def (runtime.GOROOT()) and dir are the same
   111  				// directory, prefer the spelling used in def.
   112  				if isSameDir(def, dir) {
   113  					return def
   114  				}
   115  				return dir
   116  			}
   117  			exe, err = filepath.EvalSymlinks(exe)
   118  			if err == nil {
   119  				if dir := filepath.Join(exe, "../.."); isGOROOT(dir) {
   120  					if isSameDir(def, dir) {
   121  						return def
   122  					}
   123  					return dir
   124  				}
   125  			}
   126  		}
   127  	}
   128  	return def
   129  }
   130  
   131  // isSameDir reports whether dir1 and dir2 are the same directory.
   132  func isSameDir(dir1, dir2 string) bool {
   133  	if dir1 == dir2 {
   134  		return true
   135  	}
   136  	info1, err1 := os.Stat(dir1)
   137  	info2, err2 := os.Stat(dir2)
   138  	return err1 == nil && err2 == nil && os.SameFile(info1, info2)
   139  }
   140  
   141  // isGOROOT reports whether path looks like a GOROOT.
   142  //
   143  // It does this by looking for the path/pkg/tool directory,
   144  // which is necessary for useful operation of the cmd/go tool,
   145  // and is not typically present in a GOPATH.
   146  func isGOROOT(path string) bool {
   147  	stat, err := os.Stat(filepath.Join(path, "pkg", "tool"))
   148  	if err != nil {
   149  		return false
   150  	}
   151  	return stat.IsDir()
   152  }