;;;; hacking the Unix environment
(def-alien-routine ("getenv" posix-getenv) c-string
- "Return the environment string \"name=value\" which corresponds to NAME, or
- NIL if there is none."
+ "Return the \"value\" part of the environment string \"name=value\" which
+ corresponds to NAME, or NIL if there is none."
(name c-string))
\f
;;; from stdio.h
;;; Return the real user-id associated with the current process.
(def-alien-routine ("getuid" unix-getuid) int)
-;;; Invoke readlink(2) on the file name specified by the simple string
-;;; PATH. Return up to two values: the contents of the symbolic link
-;;; if the call is successful, or NIL and the Unix error number.
+;;; Invoke readlink(2) on the file name specified by PATH. Return
+;;; (VALUES LINKSTRING NIL) on success, or (VALUES NIL ERRNO) on
+;;; failure.
(defun unix-readlink (path)
(declare (type unix-pathname path))
- (with-alien ((buf (array char 1024)))
- (syscall ("readlink" c-string (* char) int)
- (let ((string (make-string result)))
- (sb!kernel:copy-from-system-area
- (alien-sap buf) 0
- string (* sb!vm:vector-data-offset sb!vm:word-bits)
- (* result sb!vm:byte-bits))
- string)
- path (cast buf (* char)) 1024)))
+ (with-alien ((ptr (* char)
+ (alien-funcall (extern-alien
+ "wrapped_readlink"
+ (function (* char) c-string))
+ path)))
+ (if (null-alien ptr)
+ (values nil (get-errno))
+ (multiple-value-prog1
+ (values (with-alien ((c-string c-string ptr)) c-string)
+ nil)
+ (free-alien ptr)))))
;;; UNIX-UNLINK accepts a name and deletes the directory entry for that
;;; name and the file if this is the last link.
#!-sb-fluid (declaim (inline unix-fast-getrusage))
(defun unix-fast-getrusage (who)
(declare (values (member t)
- (unsigned-byte 31) (mod 1000000)
- (unsigned-byte 31) (mod 1000000)))
+ (unsigned-byte 31) (integer 0 1000000)
+ (unsigned-byte 31) (integer 0 1000000)))
(with-alien ((usage (struct rusage)))
(syscall* ("getrusage" int (* (struct rusage)))
(values t
((eql kind s-iflnk) :link)
(t :special))))))
-;;; Return the pathname with all symbolic links resolved.
-;;;
-;;; FIXME: Could we just use Unix readlink(2) instead?
+;;; 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 (simple-string pathname))
- (let ((len (length pathname))
- (pending pathname))
- (declare (fixnum len) (simple-string pending))
- (if (zerop len)
- pathname
- (let ((result (make-string 1024 :initial-element (code-char 0)))
- (fill-ptr 0)
- (name-start 0))
- (loop
- (let* ((name-end (or (position #\/ pending :start name-start) len))
- (new-fill-ptr (+ fill-ptr (- name-end name-start))))
- (replace result pending
- :start1 fill-ptr
- :end1 new-fill-ptr
- :start2 name-start
- :end2 name-end)
- (let ((kind (unix-file-kind (if (zerop name-end) "/" result) t)))
- (unless kind (return nil))
- (cond ((eq kind :link)
- (multiple-value-bind (link err) (unix-readlink result)
- (unless link
- (error 'simple-file-error
- :pathname pathname
- :format-control
- "~@<error reading link ~S: ~2I~_~A~:>"
- :format-arguments (list (subseq
- result 0 fill-ptr)
- (strerror err))))
- (cond ((or (zerop (length link))
- (char/= (schar link 0) #\/))
- ;; It's a relative link.
- (fill result (code-char 0)
- :start fill-ptr
- :end new-fill-ptr))
- ((string= result "/../" :end1 4)
- ;; It's across the super-root.
- (let ((slash (or (position #\/ result :start 4)
- 0)))
- (fill result (code-char 0)
- :start slash
- :end new-fill-ptr)
- (setf fill-ptr slash)))
- (t
- ;; It's absolute.
- (and (> (length link) 0)
- (char= (schar link 0) #\/))
- (fill result (code-char 0) :end new-fill-ptr)
- (setf fill-ptr 0)))
- (setf pending
- (if (= name-end len)
- link
- (concatenate 'simple-string
- link
- (subseq pending name-end))))
- (setf len (length pending))
- (setf name-start 0)))
- ((= name-end len)
- (return (subseq result 0 new-fill-ptr)))
- ((eq kind :directory)
- (setf (schar result new-fill-ptr) #\/)
- (setf fill-ptr (1+ new-fill-ptr))
- (setf name-start (1+ name-end)))
- (t
- (return nil))))))))))
+ (declare (type simple-string pathname))
+ (aver (not (relative-unix-pathname? pathname)))
+ (/show "entering UNIX-RESOLVE-LINKS")
+ (loop with previous-pathnames = nil do
+ (/show pathname previous-pathnames)
+ (let ((link (unix-readlink pathname)))
+ (/show 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
+ (unix-simplify-pathname
+ (if (relative-unix-pathname? link)
+ (let* ((dir-len (1+ (position #\/
+ pathname
+ :from-end t)))
+ (dir (subseq pathname 0 dir-len)))
+ (/show 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))))
(defun unix-simplify-pathname (src)
- (declare (simple-string src))
+ (declare (type simple-string src))
(let* ((src-len (length src))
(dst (make-string src-len))
(dst-len 0)
(dots 0)
(last-slash nil))
(macrolet ((deposit (char)
- `(progn
- (setf (schar dst dst-len) ,char)
- (incf dst-len))))
+ `(progn
+ (setf (schar dst dst-len) ,char)
+ (incf dst-len))))
(dotimes (src-index src-len)
(let ((char (schar src src-index)))
(cond ((char= char #\.)
((char= char #\/)
(case dots
(0
- ;; Either ``/...' or ``...//...'
+ ;; either ``/...' or ``...//...'
(unless last-slash
(setf last-slash dst-len)
(deposit char)))
(1
- ;; Either ``./...'' or ``..././...''
+ ;; either ``./...'' or ``..././...''
(decf dst-len))
(2
;; We've found ..
(setf last-slash dst-len)
(deposit char))))
(t
- ;; Something other than a dot between slashes.
+ ;; something other than a dot between slashes
(setf last-slash dst-len)
(deposit char)))
(setf dots 0))