add os.Chown

Signed-off-by: leongross <leon.gross@9elements.com>

src/os/file_anyos.go

@@ -147,6 +147,23 @@ func Chmod(name string, mode FileMode) error {
 	return nil
 }
 
+// Chown changes the numeric uid and gid of the named file.
+// If the file is a symbolic link, it changes the uid and gid of the link's target.
+// A uid or gid of -1 means to not change that value.
+// If there is an error, it will be of type *PathError.
+//
+// On Windows or Plan 9, Chown always returns the syscall.EWINDOWS or
+// EPLAN9 error, wrapped in *PathError.
+func Chown(name string, uid, gid int) error {
+	e := ignoringEINTR(func() error {
+		return syscall.Chown(name, uid, gid)
+	})
+	if e != nil {
+		return &PathError{Op: "chown", Path: name, Err: e}
+	}
+	return nil
+}
+
 // ignoringEINTR makes a function call and repeats it if it returns an
 // EINTR error. This appears to be required even though we install all
 // signal handlers with SA_RESTART: see #22838, #38033, #38836, #40846.

src/os/os_chmod_test.go

@@ -11,10 +11,12 @@ package os_test
 import (
 	. "os"
 	"runtime"
+	"syscall"
 	"testing"
 )
 
 func TestChmod(t *testing.T) {
+	// Chmod
 	f := newFile("TestChmod", t)
 	defer Remove(f.Name())
 	defer f.Close()
@@ -28,4 +30,26 @@ func TestChmod(t *testing.T) {
 		t.Fatalf("chmod %s %#o: %s", f.Name(), fm, err)
 	}
 	checkMode(t, f.Name(), fm)
+
+}
+
+func TestChown(t *testing.T) {
+	f := newFile("TestChown", t)
+	defer Remove(f.Name())
+	defer f.Close()
+
+	if runtime.GOOS != "windows" {
+		if err := Chown(f.Name(), 0, 0); err != nil {
+			t.Fatalf("chown %s 0 0: %s", f.Name(), err)
+		}
+
+		fi, err := Stat(f.Name())
+		if err != nil {
+			t.Fatalf("stat %s: %s", f.Name(), err)
+		}
+
+		if fi.Sys().(*syscall.Stat_t).Uid != 0 || fi.Sys().(*syscall.Stat_t).Gid != 0 {
+			t.Fatalf("chown %s 0 0: uid=%d gid=%d", f.Name(), fi.Sys().(*syscall.Stat_t).Uid, fi.Sys().(*syscall.Stat_t).Gid)
+		}
+	}
 }

src/syscall/syscall_libc.go

@@ -153,6 +153,15 @@ func Unlink(path string) (err error) {
 	return
 }
 
+func Chown(path string, uid, gid int) (err error) {
+	data := cstring(path)
+	fail := int(libc_chown(&data[0], uid, gid))
+	if fail < 0 {
+		err = getErrno()
+	}
+	return
+}
+
 func Faccessat(dirfd int, path string, mode uint32, flags int) (err error)
 
 func Kill(pid int, sig Signal) (err error) {
@@ -396,6 +405,11 @@ func libc_chdir(pathname *byte) int32
 //export chmod
 func libc_chmod(pathname *byte, mode uint32) int32
 
+// int chown(const char *pathname, uid_t owner, gid_t group);
+//
+//export chown
+func libc_chown(pathname *byte, owner, group int) int32
+
 // int mkdir(const char *pathname, mode_t mode);
 //
 //export mkdir