\f
;;;; LOAD-AS-SOURCE
-;;; Load a text file.
+;;; Load a text file. (Note that load-as-fasl is in another file.)
(defun load-as-source (stream verbose print)
(maybe-announce-load stream verbose)
(do ((sexpr (read stream nil *eof-object*)
(invalid-fasl-expected condition)
(invalid-fasl-fhsss condition)))))
-;;; a helper function for LOAD: Load the stuff in a file when we have
-;;; the name.
-;;;
-;;; FIXME: with the addition of the EXTERNAL-FORMAT argument, this
-;;; interface has become truly sucky.
-(defun internal-load (pathname truename if-does-not-exist verbose print
- &optional contents external-format)
- (declare (type (member nil :error) if-does-not-exist))
- (unless truename
- (if if-does-not-exist
- (error 'simple-file-error
- :pathname pathname
- :format-control "~S does not exist."
- :format-arguments (list (namestring pathname)))
- (return-from internal-load nil)))
+;; Pretty well any way of doing LOAD will expose race conditions: for
+;; example, a file might get deleted or renamed after we open it but
+;; before we find its truename. It seems useful to say that
+;; detectible ways the file system can fail to be static are good
+;; enough reason to stop loading, but to stop in a way that
+;; distinguishes errors that occur mid-way through LOAD from the
+;; initial failure to OPEN the file, so that handlers can try do
+;; defaulting only when the file didn't exist at the start of LOAD,
+;; while allowing race conditions to get through.
+(define-condition load-race-condition (error)
+ ((pathname :reader load-race-condition-pathname :initarg :pathname))
+ (:report (lambda (condition stream)
+ (format stream "~@<File ~S was deleted or renamed during LOAD.~:>"
+ (load-race-condition-pathname condition)))))
- (let ((*load-truename* truename)
- (*load-pathname* (merge-pathnames pathname)))
- (case contents
- (:source
- (with-open-file (stream truename
- :direction :input
- :if-does-not-exist if-does-not-exist
- :external-format external-format)
- (load-as-source stream verbose print)))
- (:binary
- (with-open-file (stream truename
- :direction :input
- :if-does-not-exist if-does-not-exist
- :element-type '(unsigned-byte 8))
- (load-as-fasl stream verbose print)))
- (t
- (let* ((fhsss *fasl-header-string-start-string*)
- (first-line (make-array (length fhsss)
- :element-type '(unsigned-byte 8)))
- (read-length
- (with-open-file (stream truename
- :direction :input
- :element-type '(unsigned-byte 8))
- (read-sequence first-line stream))))
- (cond
- ((and (= read-length (length fhsss))
- (do ((i 0 (1+ i)))
- ((= i read-length) t)
- (when (/= (char-code (aref fhsss i)) (aref first-line i))
- (return))))
- (internal-load pathname truename if-does-not-exist verbose print
- :binary))
- (t
- (when (string= (pathname-type truename) *fasl-file-type*)
- (error 'fasl-header-missing
- :stream (namestring truename)
- :fhsss first-line
- :expected fhsss))
- (internal-load pathname truename if-does-not-exist verbose print
- :source external-format))))))))
+(defmacro resignal-race-condition (&body body)
+ `(handler-case (progn ,@body)
+ (file-error (error)
+ (error 'load-race-condition :pathname (file-error-pathname error)))))
-;;; a helper function for INTERNAL-LOAD-DEFAULT-TYPE: Try the default
-;;; file type TYPE and return (VALUES PATHNAME TRUENAME) for a match,
-;;; or (VALUES PATHNAME NIL) if the file doesn't exist.
-;;;
-;;; This is analogous to CMU CL's TRY-DEFAULT-TYPES, but we only try a
-;;; single type. By avoiding CMU CL's generality here, we avoid having
-;;; to worry about some annoying ambiguities. (E.g. what if the
-;;; possible types are ".lisp" and ".cl", and both "foo.lisp" and
-;;; "foo.cl" exist?)
-(defun try-default-type (pathname type)
- (let ((pn (translate-logical-pathname (make-pathname :type type :defaults pathname))))
- (values pn (probe-file pn))))
+;;; The following comment preceded the pre 1.0.12.36 definition of
+;;; LOAD; it may no longer be accurate:
-;;; a helper function for LOAD: Handle the case of INTERNAL-LOAD where
-;;; the file does not exist.
-(defun internal-load-default-type
- (pathname if-does-not-exist verbose print external-format)
- (declare (type (member nil :error) if-does-not-exist))
- (multiple-value-bind (src-pn src-tn)
- (try-default-type pathname *load-source-default-type*)
- (multiple-value-bind (obj-pn obj-tn)
- (try-default-type pathname *fasl-file-type*)
- (cond
- ((and obj-tn
- src-tn
- (> (file-write-date src-tn) (file-write-date obj-tn)))
- (restart-case
- (error "The object file ~A is~@
- older than the presumed source:~% ~A."
- (namestring obj-tn)
- (namestring src-tn))
- (source () :report "load source file"
- (internal-load src-pn src-tn if-does-not-exist verbose print
- :source external-format))
- (object () :report "load object file"
- (internal-load src-pn obj-tn if-does-not-exist verbose print
- :binary))))
- (obj-tn
- (internal-load obj-pn obj-tn if-does-not-exist verbose print :binary))
- (src-pn
- (internal-load src-pn src-tn if-does-not-exist
- verbose print :source external-format))
- (t
- (internal-load pathname nil if-does-not-exist
- verbose print nil external-format))))))
+;; FIXME: Daniel Barlow's ilsb.tar ILISP-for-SBCL patches contain an
+;; implementation of "DEFUN SOURCE-FILE" which claims, in a comment,
+;; that CMU CL does not correctly record source file information when
+;; LOADing a non-compiled file. Check whether this bug exists in SBCL
+;; and fix it if so.
-;;; This function mainly sets up special bindings and then calls
-;;; sub-functions. We conditionally bind the switches with PROGV so
-;;; that people can set them in their init files and have the values
-;;; take effect. If the compiler is loaded, we make the
-;;; compiler-policy local to LOAD by binding it to itself.
-;;;
-;;; FIXME: Daniel Barlow's ilsb.tar ILISP-for-SBCL patches contain an
-;;; implementation of "DEFUN SOURCE-FILE" which claims, in a comment, that CMU
-;;; CL does not correctly record source file information when LOADing a
-;;; non-compiled file. Check whether this bug exists in SBCL and fix it if so.
-(defun load (filespec
- &key
- (verbose *load-verbose*)
- (print *load-print*)
- (if-does-not-exist t)
- (external-format :default))
+;;; This is our real LOAD. The LOAD below is just a wrapper that does
+;;; some defaulting in case the user asks us to load a file that
+;;; doesn't exist at the time we start.
+(defun %load (pathspec &key (verbose *load-verbose*) (print *load-print*)
+ (if-does-not-exist t) (external-format :default))
+ (when (streamp pathspec)
+ (let* ( ;; Bindings required by ANSI.
+ (*readtable* *readtable*)
+ (*package* (sane-package))
+ ;; FIXME: we should probably document the circumstances
+ ;; where *LOAD-PATHNAME* and *LOAD-TRUENAME* aren't
+ ;; pathnames during LOAD. ANSI makes no exceptions here.
+ (*load-pathname* (handler-case (pathname pathspec)
+ ;; FIXME: it should probably be a type
+ ;; error to try to get a pathname for a
+ ;; stream that doesn't have one, but I
+ ;; don't know if we guarantee that.
+ (error () nil)))
+ (*load-truename* (when *load-pathname*
+ (handler-case (truename *load-pathname*)
+ (file-error () nil))))
+ ;; Bindings used internally.
+ (*load-depth* (1+ *load-depth*))
+ ;; KLUDGE: I can't find in the ANSI spec where it says
+ ;; that DECLAIM/PROCLAIM of optimization policy should
+ ;; have file scope. CMU CL did this, and it seems
+ ;; reasonable, but it might not be right; after all,
+ ;; things like (PROCLAIM '(TYPE ..)) don't have file
+ ;; scope, and I can't find anything under PROCLAIM or
+ ;; COMPILE-FILE or LOAD or OPTIMIZE which justifies this
+ ;; behavior. Hmm. -- WHN 2001-04-06
+ (sb!c::*policy* sb!c::*policy*))
+ (return-from %load
+ (if (equal (stream-element-type pathspec) '(unsigned-byte 8))
+ (load-as-fasl pathspec verbose print)
+ (load-as-source pathspec verbose print)))))
+ ;; If we're here, PATHSPEC isn't a stream, so must be some other
+ ;; kind of pathname designator.
+ (with-open-file (stream pathspec
+ :element-type '(unsigned-byte 8)
+ :if-does-not-exist
+ (if if-does-not-exist :error nil))
+ (unless stream
+ (return-from %load nil))
+ (let* ((header-line (make-array
+ (length *fasl-header-string-start-string*)
+ :element-type '(unsigned-byte 8))))
+ (read-sequence header-line stream)
+ (if (mismatch header-line *fasl-header-string-start-string*
+ :test #'(lambda (code char) (= code (char-code char))))
+ (let ((truename (resignal-race-condition (probe-file stream))))
+ (when (and truename
+ (string= (pathname-type truename) *fasl-file-type*))
+ (error 'fasl-header-missing
+ :stream (namestring truename)
+ :fhsss header-line
+ :expected *fasl-header-string-start-string*)))
+ (progn
+ (file-position stream :start)
+ (return-from %load
+ (%load stream :verbose verbose :print print))))))
+ ;; Because we're just opening for input, we don't need
+ ;; WITH-OPEN-FILE's abort handling semantics, and we want to say
+ ;; it's an error for PATHSPEC to have existed before but not now, so
+ ;; WITH-OPEN-STREAM it is.
+ (with-open-stream (stream (resignal-race-condition
+ (open pathspec
+ :external-format external-format)))
+ (%load stream :verbose verbose :print print)))
+
+;; Given a simple %LOAD like the above, one can implement any
+;; particular defaulting strategy with a wrapper like this one:
+(defun load (pathspec &key (verbose *load-verbose*) (print *load-print*)
+ (if-does-not-exist :error) (external-format :default))
#!+sb-doc
"Load the file given by FILESPEC into the Lisp environment, returning
T on success."
- (let ((*load-depth* (1+ *load-depth*))
- ;; KLUDGE: I can't find in the ANSI spec where it says that
- ;; DECLAIM/PROCLAIM of optimization policy should have file
- ;; scope. CMU CL did this, and it seems reasonable, but it
- ;; might not be right; after all, things like (PROCLAIM '(TYPE
- ;; ..)) don't have file scope, and I can't find anything under
- ;; PROCLAIM or COMPILE-FILE or LOAD or OPTIMIZE which
- ;; justifies this behavior. Hmm. -- WHN 2001-04-06
- (sb!c::*policy* sb!c::*policy*)
- ;; The ANSI spec for LOAD says "LOAD binds *READTABLE* and
- ;; *PACKAGE* to the values they held before loading the file."
- (*package* (sane-package))
- (*readtable* *readtable*)
- ;; The old CMU CL LOAD function used an IF-DOES-NOT-EXIST
- ;; argument of (MEMBER :ERROR NIL) type. ANSI constrains us to
- ;; accept a generalized boolean argument value for this
- ;; externally-visible function, but the internal functions
- ;; still use the old convention.
- (internal-if-does-not-exist (if if-does-not-exist :error nil)))
- ;; FIXME: This VALUES wrapper is inherited from CMU CL. Once SBCL
- ;; gets function return type checking right, we can achieve a
- ;; similar effect better by adding FTYPE declarations.
- (values
- (if (streamp filespec)
- (if (or (equal (stream-element-type filespec)
- '(unsigned-byte 8)))
- (load-as-fasl filespec verbose print)
- (load-as-source filespec verbose print))
- (let* ((pathname (pathname filespec))
- (physical-pathname (translate-logical-pathname pathname))
- (probed-file (probe-file physical-pathname)))
- (if (or probed-file
- (pathname-type physical-pathname))
- (internal-load
- physical-pathname probed-file internal-if-does-not-exist
- verbose print nil external-format)
- (internal-load-default-type
- pathname internal-if-does-not-exist
- verbose print external-format)))))))
+ (handler-bind ((file-error
+ #'(lambda (error)
+ ;; This handler will run if %LOAD failed to OPEN
+ ;; the file to look for a fasl header.
+ (let ((pathname (file-error-pathname error)))
+ ;; As PROBE-FILE returned NIL, the file
+ ;; doesn't exist. If the filename we tried to
+ ;; open lacked a type, try loading a filename
+ ;; determined by our defaulting.
+ (when (null (handler-case (probe-file pathname)
+ (file-error (error) error)))
+ (when (null (pathname-type pathname))
+ (let ((default (probe-load-defaults pathname)))
+ (when default
+ (return-from load
+ (resignal-race-condition
+ (%load default
+ :verbose verbose
+ :print print
+ :external-format
+ external-format
+ :if-does-not-exist
+ if-does-not-exist))))))))
+ ;; If we're here, one of three things happened:
+ ;; (1) %LOAD errored and PROBE-FILE succeeded,
+ ;; in which case the file must be a bad symlink,
+ ;; unreadable, or it was created between %LOAD
+ ;; and PROBE-FILE; (2) %LOAD errored and
+ ;; PROBE-FILE errored, and so things are amiss
+ ;; in the file system (albeit possibly
+ ;; differently now than when OPEN errored); (3)
+ ;; our defaulting did not find a file. In any
+ ;; of these cases, decline to handle the
+ ;; original error or return NIL, depending on
+ ;; IF-DOES-NOT-EXIST.
+ (if if-does-not-exist
+ nil
+ (return-from load nil)))))
+ (%load pathspec :verbose verbose :print print
+ :external-format external-format)))
+
+;; This implements the defaulting SBCL seems to have inherited from
+;; CMU. This routine does not try to perform any loading; all it does
+;; is return the pathname (not the truename) of a file to be loaded,
+;; or NIL if no such file can be found. This routine is supposed to
+;; signal an error if a fasl's timestamp is older than its source
+;; file, but we protect against errors in PROBE-FILE, because any of
+;; the ways that we might fail to find a defaulted file are reasons
+;; not to load it, but not worth exposing to the user who didn't
+;; expicitly ask us to load a file with a made-up name (e.g., the
+;; defaulted filename might exceed filename length limits).
+(defun probe-load-defaults (pathname)
+ (destructuring-bind (defaulted-source-pathname
+ defaulted-source-truename
+ defaulted-fasl-pathname
+ defaulted-fasl-truename)
+ (loop for type in (list *load-source-default-type*
+ *fasl-file-type*)
+ as probe-pathname = (make-pathname :type type
+ :defaults pathname)
+ collect probe-pathname
+ collect (handler-case (probe-file probe-pathname)
+ (file-error () nil)))
+ (cond ((and defaulted-fasl-truename
+ defaulted-source-truename
+ (> (resignal-race-condition
+ (file-write-date defaulted-source-truename))
+ (resignal-race-condition
+ (file-write-date defaulted-fasl-truename))))
+ (restart-case
+ (error "The object file ~A is~@
+ older than the presumed source:~% ~A."
+ defaulted-fasl-truename
+ defaulted-source-truename)
+ (source () :report "load source file"
+ defaulted-source-pathname)
+ (object () :report "load object file"
+ defaulted-fasl-pathname)))
+ (defaulted-fasl-truename defaulted-fasl-pathname)
+ (defaulted-source-truename defaulted-source-pathname))))
\f
;;; Load a code object. BOX-NUM objects are popped off the stack for
;;; the boxed storage section, then SIZE bytes of code are read in.
projects / sbcl.git / blobdiff