+ :format-control "~@<can't find the ~A of wild pathname ~A~
+ (physicalized from ~A).~:>"
+ :format-arguments (list query-for pathname pathspec)))
+ (flet ((fail (note-format pathname errno)
+ (if errorp
+ (simple-file-perror note-format pathname errno)
+ (return-from query-file-system nil))))
+ (let ((filename (native-namestring pathname :as-file t)))
+ (multiple-value-bind (existsp errno ino mode nlink uid gid rdev size
+ atime mtime)
+ (sb!unix:unix-stat filename)
+ (declare (ignore ino nlink gid rdev size atime))
+ (if existsp
+ (case query-for
+ (:truename (nth-value
+ 0
+ (parse-native-namestring
+ ;; Note: in case the file is stat'able, POSIX
+ ;; realpath(3) gets us a canonical absolute
+ ;; filename, even if the post-merge PATHNAME
+ ;; is not absolute...
+ (multiple-value-bind (realpath errno)
+ (sb!unix:unix-realpath filename)
+ (if realpath
+ realpath
+ (fail "couldn't resolve ~A" filename errno)))
+ (pathname-host pathname)
+ (sane-default-pathname-defaults)
+ ;; ... but without any trailing slash.
+ :as-directory (eql (logand mode sb!unix:s-ifmt)
+ sb!unix:s-ifdir))))
+ (:author (sb!unix:uid-username uid))
+ (:write-date (+ unix-to-universal-time mtime)))
+ (progn
+ ;; SBCL has for many years had a policy that a pathname
+ ;; that names an existing, dangling or self-referential
+ ;; symlink denotes the symlink itself. stat(2) fails
+ ;; and sets errno to ENOENT or ELOOP respectively, but
+ ;; we must distinguish cases where the symlink exists
+ ;; from ones where there's a loop in the apparent
+ ;; containing directory.
+ #!-win32
+ (multiple-value-bind (linkp ignore ino mode nlink uid gid rdev
+ size atime mtime)
+ (sb!unix:unix-lstat filename)
+ (declare (ignore ignore ino mode nlink gid rdev size atime))
+ (when (and (or (= errno sb!unix:enoent)
+ (= errno sb!unix:eloop))
+ linkp)
+ (return-from query-file-system
+ (case query-for
+ (:truename
+ ;; So here's a trick: since lstat succeded,
+ ;; FILENAME exists, so its directory exists and
+ ;; only the non-directory part is loopy. So
+ ;; let's resolve FILENAME's directory part with
+ ;; realpath(3), in order to get a canonical
+ ;; absolute name for the directory, and then
+ ;; return a pathname having PATHNAME's name,
+ ;; type, and version, but the rest from the
+ ;; truename of the directory. Since we turned
+ ;; PATHNAME into FILENAME "as a file", FILENAME
+ ;; does not end in a slash, and so we get the
+ ;; directory part of FILENAME by reparsing
+ ;; FILENAME and masking off its name, type, and
+ ;; version bits. But note not to call ourselves
+ ;; recursively, because we don't want to
+ ;; re-merge against *DEFAULT-PATHNAME-DEFAULTS*,
+ ;; since PATHNAME may be a relative pathname.
+ (merge-pathnames
+ (nth-value
+ 0
+ (parse-native-namestring
+ (multiple-value-bind (realpath errno)
+ (sb!unix:unix-realpath
+ (native-namestring
+ (make-pathname
+ :name :unspecific
+ :type :unspecific
+ :version :unspecific
+ :defaults (parse-native-namestring
+ filename
+ (pathname-host pathname)
+ (sane-default-pathname-defaults)))))
+ (if realpath
+ realpath
+ (fail "couldn't resolve ~A" filename errno)))
+ (pathname-host pathname)
+ (sane-default-pathname-defaults)
+ :as-directory t))
+ pathname))
+ (:author (sb!unix:uid-username uid))
+ (:write-date (+ unix-to-universal-time mtime))))))
+ ;; If we're still here, the file doesn't exist; error.
+ (fail
+ (format nil "failed to find the ~A of ~~A" query-for)
+ pathspec errno))))))))
+
+
+(defun probe-file (pathspec)
+ #!+sb-doc
+ "Return the truename of PATHSPEC if the truename can be found,
+or NIL otherwise. See TRUENAME for more information."
+ (query-file-system pathspec :truename nil))
+
+(defun truename (pathspec)
+ #!+sb-doc
+ "If PATHSPEC is a pathname that names an existing file, return
+a pathname that denotes a canonicalized name for the file. If
+pathspec is a stream associated with a file, return a pathname
+that denotes a canonicalized name for the file associated with
+the stream.
+
+An error of type FILE-ERROR is signalled if no such file exists
+or if the file system is such that a canonicalized file name
+cannot be determined or if the pathname is wild.
+
+Under Unix, the TRUENAME of a symlink that links to itself or to
+a file that doesn't exist is considered to be the name of the
+broken symlink itself."
+ ;; Note that eventually this routine might be different for streams
+ ;; than for other pathname designators.
+ (if (streamp pathspec)
+ (query-file-system pathspec :truename)
+ (query-file-system pathspec :truename)))
+
+(defun file-author (pathspec)
+ #!+sb-doc
+ "Return the author of the file specified by PATHSPEC. Signal an
+error of type FILE-ERROR if no such file exists, or if PATHSPEC
+is a wild pathname."
+ (query-file-system pathspec :author))