-;;;; support routines for dealing with Unix pathnames
-
-(defun unix-file-kind (name &optional check-for-links)
- #!+sb-doc
- "Return either :FILE, :DIRECTORY, :LINK, :SPECIAL, or NIL."
- (declare (simple-string name))
- (multiple-value-bind (res dev ino mode)
- (if check-for-links (unix-lstat name) (unix-stat name))
- (declare (type (or fixnum null) mode)
- (ignore dev ino))
- (when res
- (let ((kind (logand mode s-ifmt)))
- (cond ((eql kind s-ifdir) :directory)
- ((eql kind s-ifreg) :file)
- #!-win32
- ((eql kind s-iflnk) :link)
- (t :special))))))
-
-;;; Is the Unix pathname PATHNAME relative, instead of absolute? (E.g.
-;;; "passwd" or "etc/passwd" instead of "/etc/passwd"?)
-(defun relative-unix-pathname? (pathname)
- (declare (type simple-string pathname))
- (or (zerop (length pathname))
- (char/= (schar pathname 0) #\/)))
-
-;;; Return PATHNAME with all symbolic links resolved. PATHNAME should
-;;; already be a complete absolute Unix pathname, since at least in
-;;; sbcl-0.6.12.36 we're called only from TRUENAME, and only after
-;;; paths have been converted to absolute paths, so we don't need to
-;;; try to handle any more generality than that.
-(defun unix-resolve-links (pathname)
- (declare (type simple-string pathname))
- ;; KLUDGE: The Win32 platform doesn't have symbolic links, so
- ;; short-cut this computation (and the check for being an absolute
- ;; unix pathname...)
- #!+win32 (return-from unix-resolve-links pathname)
- (aver (not (relative-unix-pathname? pathname)))
- ;; KLUDGE: readlink and lstat are unreliable if given symlinks
- ;; ending in slashes -- fix the issue here instead of waiting for
- ;; libc to change...
- ;;
- ;; but be careful! Must not strip the final slash from "/". (This
- ;; adjustment might be a candidate for being transferred into the C
- ;; code in a wrap_readlink() function, too.) CSR, 2006-01-18
- (let ((len (length pathname)))
- (when (and (> len 1) (eql #\/ (schar pathname (1- len))))
- (setf pathname (subseq pathname 0 (1- len)))))
- (/noshow "entering UNIX-RESOLVE-LINKS")
- (loop with previous-pathnames = nil do
- (/noshow pathname previous-pathnames)
- (let ((link (unix-readlink pathname)))
- (/noshow link)
- ;; Unlike the old CMU CL code, we handle a broken symlink by
- ;; returning the link itself. That way, CL:TRUENAME on a
- ;; broken link returns the link itself, so that CL:DIRECTORY
- ;; can return broken links, so that even without
- ;; Unix-specific extensions to do interesting things with
- ;; them, at least Lisp programs can see them and, if
- ;; necessary, delete them. (This is handy e.g. when your
- ;; managed-by-Lisp directories are visited by Emacs, which
- ;; creates broken links as notes to itself.)
- (if (null link)
- (return pathname)
- (let ((new-pathname
- (simplify-namestring
- (if (relative-unix-pathname? link)
- (let* ((dir-len (1+ (position #\/
- pathname
- :from-end t)))
- (dir (subseq pathname 0 dir-len)))
- (/noshow dir)
- (concatenate 'string dir link))
- link))))
- (if (unix-file-kind new-pathname)
- (setf pathname new-pathname)
- (return pathname)))))
- ;; To generalize the principle that even if portable Lisp code
- ;; can't do anything interesting with a broken symlink, at
- ;; least it should be able to see and delete it, when we
- ;; detect a cyclic link, we return the link itself. (So even
- ;; though portable Lisp code can't do anything interesting
- ;; with a cyclic link, at least it can see it and delete it.)
- (if (member pathname previous-pathnames :test #'string=)
- (return pathname)
- (push pathname previous-pathnames))))
-\f
-