contrib/sb-bsd-sockets/name-service.lisp

   1 (in-package :sb-bsd-sockets)
   2
   3 (defclass host-ent ()
   4   ((name :initarg :name :reader host-ent-name
   5          :documentation "The name of the host")
   6    ;; Deliberately not documented, since this isn't very useful,
   7    ;; and the data isn't available when using getaddrinfo(). Unfortunately
   8    ;; it is exported.
   9    (aliases :initarg :aliases :reader host-ent-aliases)
  10    ;; presently always AF_INET. Not exported.
  11    (address-type :initarg :type :reader host-ent-address-type)
  12    (addresses :initarg :addresses :reader host-ent-addresses
  13               :documentation "A list of addresses for this host."))
  14   (:documentation "This class represents the results of an address lookup."))
  15
  16 (defgeneric host-ent-address (host-ent)
  17   (:documentation "Returns some valid address for HOST-ENT."))
  18
  19 (defmethod host-ent-address ((host-ent host-ent))
  20   (car (host-ent-addresses host-ent)))
  21
  22 (defun make-host-ent (h &optional errno)
  23   (when (sb-grovel::foreign-nullp h)
  24     (name-service-error "gethostbyname" errno))
  25   (let* ((length (sockint::hostent-length h))
  26          (aliases (loop for i = 0 then (1+ i)
  27                         for al = (sb-alien:deref (sockint::hostent-aliases h) i)
  28                         while al
  29                         collect al))
  30          (addresses
  31           (loop for i = 0 then (1+ i)
  32                 for ad = (sb-alien:deref (sockint::hostent-addresses h) i)
  33                 until (sb-alien:null-alien ad)
  34                 collect (ecase (sockint::hostent-type h)
  35                           (#.sockint::af-inet
  36                            ;; CLH: Work around x86-64 darwin bug here.
  37                            ;; The length is reported as 8, when it should be 4.
  38                            #+(and darwin x86-64)
  39                            (progn
  40                              (assert (or (= length 4) (= length 8)))
  41                              (naturalize-unsigned-byte-8-array ad 4))
  42                            #-(and darwin x86-64)
  43                            (progn
  44                              (assert (= length 4))
  45                              (naturalize-unsigned-byte-8-array ad length)))
  46                           #-win32
  47                           (#.sockint::af-local
  48                            (sb-alien:cast ad sb-alien:c-string))))))
  49     (make-instance 'host-ent
  50                    :name (sockint::hostent-name h)
  51                    :type (sockint::hostent-type h)
  52                    :aliases aliases
  53                    :addresses addresses)))
  54
  55 (defun naturalize-unsigned-byte-8-array (array length)
  56   (let ((addr (make-array 4 :element-type '(unsigned-byte 8))))
  57     (dotimes (i length)
  58       (setf (elt addr i) (sb-alien:deref array i)))
  59     addr))
  60
  61 ;;; Resolving
  62
  63 (defun get-host-by-name (host-name)
  64   "Returns a HOST-ENT instance for HOST-NAME or signals a NAME-SERVICE-ERROR.
  65 HOST-NAME may also be an IP address in dotted quad notation or some other
  66 weird stuff - see gethostbyname(3) or getaddrinfo(3) for the details."
  67   #+sb-bsd-sockets-addrinfo
  68   (get-address-info host-name)
  69   #-sb-bsd-sockets-addrinfo
  70   (make-host-ent (sockint::gethostbyname host-name)))
  71
  72 (defun get-host-by-address (address)
  73   "Returns a HOST-ENT instance for ADDRESS, which should be a vector of
  74  (integer 0 255), or signals a NAME-SERVICE-ERROR.  See gethostbyaddr(3)
  75  or gethostinfo(3) for details."
  76   #+sb-bsd-sockets-addrinfo
  77   (get-name-info address)
  78   #-sb-bsd-sockets-addrinfo
  79   (sockint::with-in-addr packed-addr ()
  80     (let ((addr-vector (coerce address 'vector)))
  81       (loop for i from 0 below (length addr-vector)
  82             do (setf (sb-alien:deref (sockint::in-addr-addr packed-addr) i)
  83                      (elt addr-vector i)))
  84       (make-host-ent (sockint::gethostbyaddr packed-addr
  85                                              4
  86                                              sockint::af-inet)))))
  87
  88 ;;; Emulate the above two functions with getaddrinfo / getnameinfo
  89
  90 #+sb-bsd-sockets-addrinfo
  91 (defun get-address-info (node)
  92   (sb-alien:with-alien ((res (* (* sockint::addrinfo)) :local
  93                              (sb-alien:make-alien (* sockint::addrinfo))))
  94     (let ((err (sockint::getaddrinfo node nil nil res)))
  95       (if (zerop err)
  96           (let ((host-ent (make-instance 'host-ent
  97                                          :name node
  98                                          :type sockint::af-inet
  99                                          :aliases nil
 100                                          :addresses nil)))
 101             (loop for sap = (sb-alien:deref res) then (sockint::addrinfo-next info)
 102                   until (sb-alien::null-alien sap)
 103                   for info = (sb-alien:cast sap (* sockint::addrinfo))
 104                   ;; Only handle AF_INET currently.
 105                   do (when (eq (sockint::addrinfo-family info) sockint::af-inet)
 106                        (let* ((sockaddr (sockint::addrinfo-addr info))
 107                               (address (sockint::sockaddr-in-addr sockaddr)))
 108                          ;; The same effective result can be multiple time
 109                          ;; in the list, with different socktypes. Only record
 110                          ;; each address once.
 111                          (setf (slot-value host-ent 'addresses)
 112                                (adjoin (naturalize-unsigned-byte-8-array address
 113                                                                          4)
 114                                        (host-ent-addresses host-ent)
 115                                        :test 'equalp)))))
 116             (sockint::free-addrinfo (sb-alien:deref res))
 117             host-ent)
 118           (addrinfo-error "getaddrinfo" err)))))
 119
 120 (defconstant ni-max-host 1025)
 121
 122 #+sb-bsd-sockets-addrinfo
 123 (defun get-name-info (address)
 124   (assert (= (length address) 4))
 125   (sockint::with-sockaddr-in sockaddr ()
 126     (sb-alien:with-alien ((host-buf (array char #.ni-max-host)))
 127       (setf (sockint::sockaddr-in-family sockaddr) sockint::af-inet)
 128       (dotimes (i 4)
 129         (setf (sb-alien:deref (sockint::sockaddr-in-addr sockaddr) i)
 130               (aref address i)))
 131       (let ((err (sockint::getnameinfo (sb-alien:alien-sap sockaddr)
 132                                        (sb-alien:alien-size sockint::sockaddr-in :bytes)
 133                                        (sb-alien:cast host-buf (* char)) ni-max-host
 134                                        nil 0
 135                                        sockint::ni-namereqd)))
 136         (if (zerop err)
 137             (make-instance 'host-ent
 138                            :name (sb-alien::c-string-to-string
 139                                   (sb-alien:alien-sap host-buf)
 140                                   (sb-impl::default-external-format)
 141                                   'character)
 142                            :type sockint::af-inet
 143                            :aliases nil
 144                            :addresses (list address))
 145             (addrinfo-error "getnameinfo" err))))))
 146
 147 ;;; Error handling
 148
 149 (defvar *name-service-errno* 0
 150   "The value of h_errno, after it's been fetched from Unix-land by calling
 151 GET-NAME-SERVICE-ERRNO")
 152
 153 (defun name-service-error (where &optional errno)
 154   ;; There was a dummy docstring here for the texinfo extractor, but I
 155   ;; see no reason for this to be documented in the manual, and removed
 156   ;; it. -- JES
 157   (let ((*name-service-errno* (get-name-service-errno errno)))
 158     ;; Comment next to NETDB_INTERNAL in netdb.h says "See errno.".
 159     ;; This special case treatment hasn't actually been tested yet.
 160     #-win32
 161     (if (= *name-service-errno* sockint::NETDB-INTERNAL)
 162         (socket-error where)
 163         (let ((condition
 164                (condition-for-name-service-errno *name-service-errno*)))
 165           (error condition :errno *name-service-errno* :syscall where)))))
 166
 167 (defun addrinfo-error (where error-code)
 168   (let ((condition (condition-for-name-service-error-code error-code)))
 169     (error condition :error-code error-code :syscall where)))
 170
 171 (define-condition name-service-error (condition)
 172   ((errno :initform nil :initarg :errno :reader name-service-error-errno)
 173    (error-code :initform nil :initarg :error-code
 174                :reader name-service-error-error-code)
 175    (symbol :initform nil :initarg :symbol :reader name-service-error-symbol)
 176    (syscall :initform "an unknown location" :initarg :syscall :reader name-service-error-syscall))
 177   (:report (lambda (c s)
 178              (let* ((errno (name-service-error-errno c))
 179                     (error-code (name-service-error-error-code c)))
 180                (format s "Name service error in \"~A\": ~A (~A)"
 181                        (name-service-error-syscall c)
 182                        (or (name-service-error-symbol c)
 183                            errno
 184                            error-code)
 185                        (get-name-service-error-message errno error-code))))))
 186
 187 (defparameter *conditions-for-name-service-errno* nil)
 188 ;; getaddrinfo and getnameinfo return an error code, rather than using
 189 ;; h_errno.  While on Linux there's no overlap between their possible
 190 ;; values, this doesn't seem to be guaranteed on all systems.
 191 (defparameter *conditions-for-name-service-error-code* nil)
 192
 193 ;; Define a special name-service-error for variour error cases, and associate
 194 ;; them with the matching h_errno / error code.
 195 (defmacro define-name-service-condition (errno-symbol error-code-symbol name)
 196   `(progn
 197      (define-condition ,name (name-service-error)
 198        ((errno-symbol :reader name-service-error-errno-symbol
 199                       :initform (quote ,errno-symbol))
 200         (error-code-symbol :reader name-service-error-error-code-symbol
 201                            :initform (quote ,error-code-symbol))))
 202      (push (cons ,errno-symbol (quote ,name))
 203            *conditions-for-name-service-errno*)
 204      #+sb-bsd-sockets-addrinfo
 205      (push (cons ,error-code-symbol (quote ,name))
 206            *conditions-for-name-service-error-code*)))
 207
 208 #-win32
 209 (define-name-service-condition
 210     sockint::NETDB-INTERNAL
 211     nil ;; Doesn't map directly to any getaddrinfo error code
 212     netdb-internal-error)
 213 #-win32
 214 (define-name-service-condition
 215     sockint::NETDB-SUCCESS
 216     nil ;; Doesn't map directly to any getaddrinfo error code
 217     netdb-success-error)
 218 (define-name-service-condition
 219     sockint::HOST-NOT-FOUND
 220     sockint::EAI-NONAME
 221     host-not-found-error)
 222 (define-name-service-condition
 223     sockint::TRY-AGAIN
 224     sockint::EAI-AGAIN
 225     try-again-error)
 226 (define-name-service-condition
 227     sockint::NO-RECOVERY
 228     sockint::EAI-FAIL
 229     no-recovery-error)
 230 (define-name-service-condition
 231     sockint::NO-ADDRESS  ;; Also defined as NO-DATA, with the same value
 232     #-freebsd sockint::EAI-NODATA #+freebsd nil
 233     no-address-error)
 234
 235 (defun condition-for-name-service-errno (err)
 236   (or (cdr (assoc err *conditions-for-name-service-errno* :test #'eql))
 237       'name-service-error))
 238
 239 (defun condition-for-name-service-error-code (err)
 240   (or (cdr (assoc err *conditions-for-name-service-error-code* :test #'eql))
 241       'name-service-error))
 242
 243 (defun get-name-service-errno (&optional errno)
 244   (setf *name-service-errno*
 245         (or errno
 246             (sb-alien:alien-funcall
 247              #-win32
 248              (sb-alien:extern-alien "get_h_errno" (function integer))
 249              #+win32
 250              (sb-alien:extern-alien "WSAGetLastError" (function integer))))))
 251
 252 (defun get-name-service-error-message (errno error-code)
 253   #-win32
 254   (if errno
 255       (sockint::h-strerror errno)
 256       (sockint::gai-strerror error-code)))