]> Cypherpunks repositories - gostls13.git/commitdiff
os: add Executable() (string, error)
authorShenghou Ma <minux@golang.org>
Sun, 1 Nov 2015 09:18:58 +0000 (04:18 -0500)
committerBrad Fitzpatrick <bradfitz@golang.org>
Mon, 7 Nov 2016 22:34:48 +0000 (22:34 +0000)
// Executable returns the path name for the executable that started
// the current process. There is no guarantee that the path is still
// pointing to the correct executable. If a symlink was used to start
// the process, depending on the operating system, the result might
// be the symlink or the path it pointed to. If a stable result is
// needed, path/filepath.EvalSymlinks might help.
//
// Executable returns an absolute path unless an error occurred.
//
// The main use case is finding resources located relative to an
// executable.
//
// Executable is not supported on nacl or OpenBSD (unless procfs is
// mounted.)
func Executable() (string, error) {
return executable()
}

Fixes #12773.

Change-Id: I469738d905b12f0b633ea4d88954f8859227a88c
Reviewed-on: https://go-review.googlesource.com/16551
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
src/os/executable.go [new file with mode: 0644]
src/os/executable_darwin.go [new file with mode: 0644]
src/os/executable_freebsd.go [new file with mode: 0644]
src/os/executable_plan9.go [new file with mode: 0644]
src/os/executable_procfs.go [new file with mode: 0644]
src/os/executable_solaris.go [new file with mode: 0644]
src/os/executable_test.go [new file with mode: 0644]
src/os/executable_windows.go [new file with mode: 0644]

diff --git a/src/os/executable.go b/src/os/executable.go
new file mode 100644 (file)
index 0000000..8c21246
--- /dev/null
@@ -0,0 +1,23 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package os
+
+// Executable returns the path name for the executable that started
+// the current process. There is no guarantee that the path is still
+// pointing to the correct executable. If a symlink was used to start
+// the process, depending on the operating system, the result might
+// be the symlink or the path it pointed to. If a stable result is
+// needed, path/filepath.EvalSymlinks might help.
+//
+// Executable returns an absolute path unless an error occurred.
+//
+// The main use case is finding resources located relative to an
+// executable.
+//
+// Executable is not supported on nacl or OpenBSD (unless procfs is
+// mounted.)
+func Executable() (string, error) {
+       return executable()
+}
diff --git a/src/os/executable_darwin.go b/src/os/executable_darwin.go
new file mode 100644 (file)
index 0000000..ce5b814
--- /dev/null
@@ -0,0 +1,24 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package os
+
+var executablePath string // set by ../runtime/os_darwin.go
+
+var initCwd, initCwdErr = Getwd()
+
+func executable() (string, error) {
+       ep := executablePath
+       if ep[0] != '/' {
+               if initCwdErr != nil {
+                       return ep, initCwdErr
+               }
+               if len(ep) > 2 && ep[0:2] == "./" {
+                       // skip "./"
+                       ep = ep[2:]
+               }
+               ep = initCwd + "/" + ep
+       }
+       return ep, nil
+}
diff --git a/src/os/executable_freebsd.go b/src/os/executable_freebsd.go
new file mode 100644 (file)
index 0000000..ccaf8e6
--- /dev/null
@@ -0,0 +1,33 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package os
+
+import (
+       "syscall"
+       "unsafe"
+)
+
+func executable() (string, error) {
+       mib := [4]int32{1 /* CTL_KERN */, 14 /* KERN_PROC */, 12 /* KERN_PROC_PATHNAME */, -1}
+
+       n := uintptr(0)
+       // get length
+       _, _, err := syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, 0, uintptr(unsafe.Pointer(&n)), 0, 0)
+       if err != 0 {
+               return "", err
+       }
+       if n == 0 { // shouldn't happen
+               return "", nil
+       }
+       buf := make([]byte, n)
+       _, _, err = syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, uintptr(unsafe.Pointer(&buf[0])), uintptr(unsafe.Pointer(&n)), 0, 0)
+       if err != 0 {
+               return "", err
+       }
+       if n == 0 { // shouldn't happen
+               return "", nil
+       }
+       return string(buf[:n-1]), nil
+}
diff --git a/src/os/executable_plan9.go b/src/os/executable_plan9.go
new file mode 100644 (file)
index 0000000..a5947ea
--- /dev/null
@@ -0,0 +1,19 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build plan9
+
+package os
+
+import "syscall"
+
+func executable() (string, error) {
+       fn := "/proc/" + itoa(Getpid()) + "/text"
+       f, err := Open(fn)
+       if err != nil {
+               return "", err
+       }
+       defer f.Close()
+       return syscall.Fd2path(int(f.Fd()))
+}
diff --git a/src/os/executable_procfs.go b/src/os/executable_procfs.go
new file mode 100644 (file)
index 0000000..597ab7d
--- /dev/null
@@ -0,0 +1,36 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux netbsd openbsd dragonfly nacl
+
+package os
+
+import (
+       "errors"
+       "runtime"
+)
+
+// We query the executable path at init time to avoid the problem of
+// readlink returns a path appended with " (deleted)" when the original
+// binary gets deleted.
+var executablePath, executablePathErr = func () (string, error) {
+       var procfn string
+       switch runtime.GOOS {
+       default:
+               return "", errors.New("Executable not implemented for " + runtime.GOOS)
+       case "linux":
+               procfn = "/proc/self/exe"
+       case "netbsd":
+               procfn = "/proc/curproc/exe"
+       case "openbsd":
+               procfn = "/proc/curproc/file"
+       case "dragonfly":
+               procfn = "/proc/curproc/file"
+       }
+       return Readlink(procfn)
+}()
+
+func executable() (string, error) {
+       return executablePath, executablePathErr
+}
diff --git a/src/os/executable_solaris.go b/src/os/executable_solaris.go
new file mode 100644 (file)
index 0000000..80f9372
--- /dev/null
@@ -0,0 +1,27 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package os
+
+import "syscall"
+
+var initCwd, initCwdErr = Getwd()
+
+func executable() (string, error) {
+       path, err := syscall.Getexecname()
+       if err != nil {
+               return path, err
+       }
+       if len(path) > 0 && path[0] != '/' {
+               if initCwdErr != nil {
+                       return path, initCwdErr
+               }
+               if len(path) > 2 && path[0:2] == "./" {
+                       // skip "./"
+                       path = path[2:]
+               }
+               return initCwd + "/" + path, nil
+       }
+       return path, nil
+}
diff --git a/src/os/executable_test.go b/src/os/executable_test.go
new file mode 100644 (file)
index 0000000..a4d8909
--- /dev/null
@@ -0,0 +1,87 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package os_test
+
+import (
+       "fmt"
+       "internal/testenv"
+       "os"
+       osexec "os/exec"
+       "path/filepath"
+       "runtime"
+       "testing"
+)
+
+const executable_EnvVar = "OSTEST_OUTPUT_EXECPATH"
+
+func TestExecutable(t *testing.T) {
+       testenv.MustHaveExec(t) // will also execlude nacl, which doesn't support Executable anyway
+       ep, err := os.Executable()
+       if err != nil {
+               switch goos := runtime.GOOS; goos {
+               case "openbsd": // procfs is not mounted by default
+                       t.Skipf("Executable failed on %s: %v, expected", goos, err)
+               }
+               t.Fatalf("Executable failed: %v", err)
+       }
+       // we want fn to be of the form "dir/prog"
+       dir := filepath.Dir(filepath.Dir(ep))
+       fn, err := filepath.Rel(dir, ep)
+       if err != nil {
+               t.Fatalf("filepath.Rel: %v", err)
+       }
+       cmd := &osexec.Cmd{}
+       // make child start with a relative program path
+       cmd.Dir = dir
+       cmd.Path = fn
+       // forge argv[0] for child, so that we can verify we could correctly
+       // get real path of the executable without influenced by argv[0].
+       cmd.Args = []string{"-", "-test.run=XXXX"}
+       cmd.Env = append(os.Environ(), fmt.Sprintf("%s=1", executable_EnvVar))
+       out, err := cmd.CombinedOutput()
+       if err != nil {
+               t.Fatalf("exec(self) failed: %v", err)
+       }
+       outs := string(out)
+       if !filepath.IsAbs(outs) {
+               t.Fatalf("Child returned %q, want an absolute path", out)
+       }
+       if !sameFile(outs, ep) {
+               t.Fatalf("Child returned %q, not the same file as %q", out, ep)
+       }
+}
+
+func sameFile(fn1, fn2 string) bool {
+       fi1, err := os.Stat(fn1)
+       if err != nil {
+               return false
+       }
+       fi2, err := os.Stat(fn2)
+       if err != nil {
+               return false
+       }
+       return os.SameFile(fi1, fi2)
+}
+
+func init() {
+       if e := os.Getenv(executable_EnvVar); e != "" {
+               // first chdir to another path
+               dir := "/"
+               if runtime.GOOS == "windows" {
+                       cwd, err := os.Getwd()
+                       if err != nil {
+                               panic(err)
+                       }
+                       dir = filepath.VolumeName(cwd)
+               }
+               os.Chdir(dir)
+               if ep, err := os.Executable(); err != nil {
+                       fmt.Fprint(os.Stderr, "ERROR: ", err)
+               } else {
+                       fmt.Fprint(os.Stderr, ep)
+               }
+               os.Exit(0)
+       }
+}
diff --git a/src/os/executable_windows.go b/src/os/executable_windows.go
new file mode 100644 (file)
index 0000000..fc5cf86
--- /dev/null
@@ -0,0 +1,32 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package os
+
+import (
+       "internal/syscall/windows"
+       "syscall"
+)
+
+func getModuleFileName(handle syscall.Handle) (string, error) {
+       n := uint32(1024)
+       var buf []uint16
+       for {
+               buf = make([]uint16, n)
+               r, err := windows.GetModuleFileName(handle, &buf[0], n)
+               if err != nil {
+                       return "", err
+               }
+               if r < n {
+                       break
+               }
+               // r == n means n not big enough
+               n += 1024
+       }
+       return syscall.UTF16ToString(buf), nil
+}
+
+func executable() (string, error) {
+       return getModuleFileName(0)
+}