{call: "Seteuid(1)", fn: func() error { return syscall.Seteuid(1) }, filter: "Uid:", expect: "\t0\t1\t0\t1"},
		{call: "Setuid(0)", fn: func() error { return syscall.Setuid(0) }, filter: "Uid:", expect: "\t0\t0\t0\t0"},

		{call: "Setgid(1)", fn: func() error { return syscall.Setgid(1) }, filter: "Gid:", expect: "\t1\t1\t1\t1"},

		Method: Store,
		Mode:   0666,
	},
	{
		Name:   "bar",
		Data:   nil, // large data set in the test
		Method: Deflate,
		Mode:   0644,
	},
	{
		Name:   "setuid",
		Data:   []byte("setuid file"),
		Method: Deflate,
		Mode:   0755 | fs.ModeSetuid,
	},
	{
		Name:   "setgid",
		Data:   []byte("setgid file"),
		Method: Deflate,
		Mode:   0755 | fs.ModeSetgid,
	},
	{

	// Set file permission bits.
	mode = fs.FileMode(fi.h.Mode).Perm()

	// Set setuid, setgid and sticky bits.
	if fi.h.Mode&c_ISUID != 0 {
		mode |= fs.ModeSetuid
	}
	if fi.h.Mode&c_ISGID != 0 {
		mode |= fs.ModeSetgid
	}
	if fi.h.Mode&c_ISVTX != 0 {
		mode |= fs.ModeSticky
	}

	// Set file mode bits; clear perm, setuid, setgid, and sticky bits.
	switch m := fs.FileMode(fi.h.Mode) &^ 07777; m {

		h: &Header{
			Name:     "dev/initctl",
			Mode:     0600,
			Size:     0,
			ModTime:  time.Unix(1360578949, 0),
			Typeflag: TypeFifo,
		},
		fm: 0600 | fs.ModeNamedPipe,
	}, {
		// setuid.
		h: &Header{
			Name:     "bin/su",
			Mode:     0755 | c_ISUID,
			Size:     23232,
			ModTime:  time.Unix(1355405093, 0),
			Typeflag: TypeReg,
		},
		fm: 0755 | fs.ModeSetuid,
	}, {