Ejemplo n.º 1
0
func lookupUnixGid(gid int) (*Group, error) {
	var grp syscall.Group
	var result *syscall.Group

	buf := alloc(groupBuffer)
	defer buf.free()

	err := retryWithBuffer(buf, func() syscall.Errno {
		syscall.Entersyscall()
		rv := libc_getgrgid_r(syscall.Gid_t(gid),
			&grp,
			buf.ptr,
			buf.size,
			&result)
		syscall.Exitsyscall()
		if rv != 0 {
			return syscall.GetErrno()
		}
		return 0
	})
	if err != nil {
		return nil, fmt.Errorf("user: lookup groupid %d: %v", gid, err)
	}
	if result == nil {
		return nil, UnknownGroupIdError(strconv.Itoa(gid))
	}
	return buildGroup(&grp), nil
}
Ejemplo n.º 2
0
func listGroups(u *User) ([]string, error) {
	ug, err := strconv.Atoi(u.Gid)
	if err != nil {
		return nil, fmt.Errorf("user: list groups for %s: invalid gid %q", u.Username, u.Gid)
	}
	userGID := syscall.Gid_t(ug)
	nameC, err := syscall.BytePtrFromString(u.Username)
	if err != nil {
		return nil, fmt.Errorf("user: invalid user name %q: %v", strconv.Quote(u.Username), err)
	}

	n := int32(256)
	gidsC := make([]syscall.Gid_t, n)
	syscall.Entersyscall()
	rv := libc_getgrouplist(nameC, userGID, &gidsC[0], &n)
	syscall.Exitsyscall()
	if rv == -1 {
		// More than initial buffer, but now n contains the correct size.
		const maxGroups = 2048
		if n > maxGroups {
			return nil, fmt.Errorf("user: list groups for %s: member of more than %d groups", u.Username, maxGroups)
		}
		gidsC = make([]syscall.Gid_t, n)
		syscall.Entersyscall()
		rv := libc_getgrouplist(nameC, userGID, &gidsC[0], &n)
		syscall.Exitsyscall()
		if rv == -1 {
			return nil, fmt.Errorf("user: list groups for %s failed (changed groups?)", u.Username)
		}
	}
	gidsC = gidsC[:n]
	gids := make([]string, 0, n)
	for _, g := range gidsC[:n] {
		gids = append(gids, strconv.Itoa(int(g)))
	}
	return gids, nil
}