(c-system-include "unistd.h")
(c-system-include "pwd.h")
(c-system-include "sys/types.h")

;;> @subsubsubsection{@scheme{(user-information name-or-id)}}

;;> Returns the password entry for the given user.  @var{name-or-id}
;;> should be a string indicating the user name, or an integer
;;> for the user id.

(define-c-struct passwd
  predicate: user?
  (string  pw_name     user-name)
  (string  pw_passwd   user-password)
  (uid_t   pw_uid      user-id)
  (gid_t   pw_gid      user-group-id)
  (string  pw_gecos    user-gecos)
  (string  pw_dir      user-home)
  (string  pw_shell    user-shell))

;;> Accessors for the password entry structure returned by
;;> @scheme{user-information}.
;;/

(define-c uid_t (current-user-id "getuid") ())
(define-c gid_t (current-group-id "getgid") ())
(define-c uid_t (current-effective-user-id "geteuid") ())
(define-c gid_t (current-effective-group-id "getegid") ())

(define-c errno (set-current-user-id! "setuid") (uid_t))
(define-c errno (set-current-effective-user-id! "seteuid") (uid_t))
(define-c errno (set-current-group-id! "setgid") (gid_t))
(define-c errno (set-current-effective-group-id! "setegid") (gid_t))

;;> Accessors for the current user credentials.
;;/

;;> Returns the session id of the specified process,
;;> defaulting to the current process.

(define-c pid_t (current-session-id "getsid") ((default 0 pid_t)))

;;> Creates a new session.

(define-c pid_t (create-session "setsid") ())

;;> Set @var{string} to be the new root directory, so that
;;> paths beginning with "/" are resolved relative to the
;;> new root.

(define-c errno (set-root-directory! "chroot") (string))

(define-c errno getpwuid_r
  (uid_t (result passwd) (result (array char arg3))
         (value 1024 int) (result pointer passwd)))

(define-c errno getpwnam_r
  (string (result passwd) (result (array char arg3))
          (value 1024 int) (result pointer passwd)))