1 ;;;; stuff related to the toplevel read-eval-print loop, plus some
2 ;;;; other miscellaneous functions that we don't have any better place
5 ;;;; This software is part of the SBCL system. See the README file for
8 ;;;; This software is derived from the CMU CL system, which was
9 ;;;; written at Carnegie Mellon University and released into the
10 ;;;; public domain. The software is in the public domain and is
11 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
12 ;;;; files for more information.
14 (in-package "SB!IMPL")
16 ;;;; magic specials initialized by GENESIS
18 ;;; FIXME: The DEFVAR here is redundant with the (DECLAIM (SPECIAL ..))
19 ;;; of all static symbols in early-impl.lisp.
21 (defvar *current-catch-block*)
22 (defvar *current-unwind-protect-block*)
23 (defvar *free-interrupt-context-index*))
25 ;;; specials initialized by !COLD-INIT
27 ;;; FIXME: These could be converted to DEFVARs.
28 (declaim (special *gc-inhibit* *need-to-collect-garbage*
29 *before-gc-hooks* *after-gc-hooks*
30 #!+x86 *pseudo-atomic-atomic*
31 #!+x86 *pseudo-atomic-interrupted*
32 sb!unix::*interrupts-enabled*
33 sb!unix::*interrupt-pending*
34 *type-system-initialized*))
36 (defvar *cold-init-complete-p*)
38 ;;; counts of nested errors (with internal errors double-counted)
39 (defvar *maximum-error-depth*)
40 (defvar *current-error-depth*)
42 ;;;; miscellaneous utilities for working with with TOPLEVEL
44 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
45 ;;; by QUIT) is caught and any final processing and return codes are
46 ;;; handled appropriately.
47 (defmacro handling-end-of-the-world (&body body)
48 (with-unique-names (caught)
49 `(let ((,caught (catch '%end-of-the-world
50 (/show0 "inside CATCH '%END-OF-THE-WORLD")
52 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
53 (flush-standard-output-streams)
54 (sb!thread::terminate-session)
55 (/show0 "calling UNIX-EXIT")
56 (sb!unix:unix-exit ,caught))))
58 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
60 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
62 (defmacro infinite-error-protect (&rest forms)
63 `(unless (infinite-error-protector)
64 (/show0 "back from INFINITE-ERROR-PROTECTOR")
65 (let ((*current-error-depth* (1+ *current-error-depth*)))
66 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
67 ;; arbitrary truncation
68 #!+sb-show (sb!debug:backtrace 8)
71 ;;; a helper function for INFINITE-ERROR-PROTECT
72 (defun infinite-error-protector ()
73 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
74 (/hexstr *current-error-depth*)
75 (cond ((not *cold-init-complete-p*)
76 (%primitive print "Argh! error in cold init, halting")
77 (%primitive sb!c:halt))
78 ((or (not (boundp '*current-error-depth*))
79 (not (realp *current-error-depth*))
80 (not (boundp '*maximum-error-depth*))
81 (not (realp *maximum-error-depth*)))
82 (%primitive print "Argh! corrupted error depth, halting")
83 (%primitive sb!c:halt))
84 ((> *current-error-depth* *maximum-error-depth*)
85 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
86 (/hexstr *maximum-error-depth*)
87 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
91 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
94 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
97 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
98 ;;; one point (shown below), and SBCL cross-compiled it without
99 ;;; warning about FORMS being undefined. Check whether that problem
100 ;;; (missing warning) is repeatable in the final system and if so, fix
103 (defun infinite-error-protector ()
104 `(cond ((not *cold-init-complete-p*)
105 (%primitive print "Argh! error in cold init, halting")
106 (%primitive sb!c:halt))
107 ((or (not (boundp '*current-error-depth*))
108 (not (realp *current-error-depth*))
109 (not (boundp '*maximum-error-depth*))
110 (not (realp *maximum-error-depth*)))
111 (%primitive print "Argh! corrupted error depth, halting")
112 (%primitive sb!c:halt))
113 ((> *current-error-depth* *maximum-error-depth*)
114 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
115 (error-error "Help! "
116 *current-error-depth*
118 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
122 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
126 ;;;; miscellaneous external functions
130 "This function causes execution to be suspended for N seconds. N may
131 be any non-negative, non-complex number."
132 (when (or (not (realp n))
134 (error 'simple-type-error
135 :format-control "invalid argument to SLEEP: ~S"
136 :format-arguments (list n)
138 :expected-type '(real 0)))
139 (multiple-value-bind (sec usec)
142 (multiple-value-bind (sec frac)
144 (values sec (truncate frac 1e-6))))
145 (sb!unix:unix-select 0 0 0 0 sec usec))
148 ;;;; SCRUB-CONTROL-STACK
150 (defconstant bytes-per-scrub-unit 2048)
152 ;;; Zero the unused portion of the control stack so that old objects
153 ;;; are not kept alive because of uninitialized stack variables.
155 ;;; "To summarize the problem, since not all allocated stack frame
156 ;;; slots are guaranteed to be written by the time you call an another
157 ;;; function or GC, there may be garbage pointers retained in your
158 ;;; dead stack locations. The stack scrubbing only affects the part
159 ;;; of the stack from the SP to the end of the allocated stack."
160 ;;; - ram, on cmucl-imp, Tue, 25 Sep 2001
162 ;;; So, as an (admittedly lame) workaround, from time to time we call
163 ;;; scrub-control-stack to zero out all the unused portion. This is
164 ;;; supposed to happen when the stack is mostly empty, so that we have
165 ;;; a chance of clearing more of it: callers are currently (2002.07.18)
168 (defun scrub-control-stack ()
169 (declare (optimize (speed 3) (safety 0))
170 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
172 #!-stack-grows-downward-not-upward
173 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
174 (initial-offset (logand csp (1- bytes-per-scrub-unit)))
176 (- (sb!vm:fixnumize sb!vm:*control-stack-end*)
177 sb!c:*backend-page-size*)))
179 ((scrub (ptr offset count)
180 (declare (type system-area-pointer ptr)
181 (type (unsigned-byte 16) offset)
182 (type (unsigned-byte 20) count)
183 (values (unsigned-byte 20)))
184 (cond ((>= (sap-int ptr) end-of-stack) 0)
185 ((= offset bytes-per-scrub-unit)
186 (look (sap+ ptr bytes-per-scrub-unit) 0 count))
188 (setf (sap-ref-32 ptr offset) 0)
189 (scrub ptr (+ offset sb!vm:n-word-bytes) count))))
190 (look (ptr offset count)
191 (declare (type system-area-pointer ptr)
192 (type (unsigned-byte 16) offset)
193 (type (unsigned-byte 20) count)
194 (values (unsigned-byte 20)))
195 (cond ((>= (sap-int ptr) end-of-stack) 0)
196 ((= offset bytes-per-scrub-unit)
198 ((zerop (sap-ref-32 ptr offset))
199 (look ptr (+ offset sb!vm:n-word-bytes) count))
201 (scrub ptr offset (+ count sb!vm:n-word-bytes))))))
202 (declare (type (unsigned-byte 32) csp))
203 (scrub (int-sap (- csp initial-offset))
204 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
207 #!+stack-grows-downward-not-upward
208 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
209 (end-of-stack (+ (sb!vm:fixnumize sb!vm:*control-stack-start*)
210 sb!c:*backend-page-size*))
211 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
213 ((scrub (ptr offset count)
214 (declare (type system-area-pointer ptr)
215 (type (unsigned-byte 16) offset)
216 (type (unsigned-byte 20) count)
217 (values (unsigned-byte 20)))
218 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
219 (cond ((< (sap-int loc) end-of-stack) 0)
220 ((= offset bytes-per-scrub-unit)
221 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
223 (t ;; need to fix bug in %SET-STACK-REF
224 (setf (sap-ref-32 loc 0) 0)
225 (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
226 (look (ptr offset count)
227 (declare (type system-area-pointer ptr)
228 (type (unsigned-byte 16) offset)
229 (type (unsigned-byte 20) count)
230 (values (unsigned-byte 20)))
231 (let ((loc (int-sap (- (sap-int ptr) offset))))
232 (cond ((< (sap-int loc) end-of-stack) 0)
233 ((= offset bytes-per-scrub-unit)
235 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
236 (look ptr (+ offset sb!vm:n-word-bytes) count))
238 (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
239 (declare (type (unsigned-byte 32) csp))
240 (scrub (int-sap (+ csp initial-offset))
241 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
244 ;;;; the default toplevel function
248 "a list of all the values returned by the most recent top level EVAL")
249 (defvar // nil #!+sb-doc "the previous value of /")
250 (defvar /// nil #!+sb-doc "the previous value of //")
251 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
252 (defvar ** nil #!+sb-doc "the previous value of *")
253 (defvar *** nil #!+sb-doc "the previous value of **")
254 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
255 (defvar ++ nil #!+sb-doc "the previous value of +")
256 (defvar +++ nil #!+sb-doc "the previous value of ++")
257 (defvar - nil #!+sb-doc "the form currently being evaluated")
259 (defun interactive-eval (form)
260 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
261 +++, ++, +, ///, //, /, and -."
266 (make-null-interactive-lexenv)))))
277 ;; The bogon returned an unbound marker.
278 ;; FIXME: It would be safer to check every one of the values in RESULTS,
279 ;; instead of just the first one.
281 (cerror "Go on with * set to NIL."
282 "EVAL returned an unbound marker."))
285 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
286 ;;; output streams before proceeding.
287 (defun flush-standard-output-streams ()
288 (dolist (name '(*debug-io*
293 (finish-output (symbol-value name)))
296 ;;; the default system top level function
297 (defun toplevel-init ()
299 (/show0 "entering TOPLEVEL-INIT")
300 (sb!thread::init-job-control)
301 (sb!thread::get-foreground)
302 (let (;; value of --sysinit option
304 ;; value of --userinit option
306 ;; values of --eval options, in reverse order; and also any
307 ;; other options (like --load) which're translated into --eval
309 ;; The values are stored as strings, so that they can be
310 ;; passed to READ only after their predecessors have been
311 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL
312 ;; form creates a package referred to in the next EVAL form.
314 ;; Has a --noprint option been seen?
316 ;; everything in *POSIX-ARGV* except for argv[0]=programname
317 (options (rest *posix-argv*)))
319 (declare (type list options))
321 (/show0 "done with outer LET in TOPLEVEL-INIT")
323 ;; FIXME: There are lots of ways for errors to happen around here
324 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
325 ;; READ an --eval string). Make sure that they're handled
326 ;; reasonably. Also, perhaps all errors while parsing the command
327 ;; line should cause the system to QUIT, instead of trying to go
328 ;; into the Lisp debugger, since trying to go into the debugger
329 ;; gets into various annoying issues of where we should go after
330 ;; the user tries to return from the debugger.
332 ;; Parse command line options.
333 (loop while options do
334 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
335 (let ((option (first options)))
336 (flet ((pop-option ()
339 (error "unexpected end of command line options"))))
340 (cond ((string= option "--sysinit")
343 (error "multiple --sysinit options")
344 (setf sysinit (pop-option))))
345 ((string= option "--userinit")
348 (error "multiple --userinit options")
349 (setf userinit (pop-option))))
350 ((string= option "--eval")
352 (push (pop-option) reversed-evals))
353 ((string= option "--load")
356 ;; FIXME: see BUG 296
357 (concatenate 'string "(|LOAD| \"" (pop-option) "\")")
359 ((string= option "--noprint")
362 ;; FIXME: --noprogrammer was deprecated in 0.7.5, and
363 ;; in a year or so this backwards compatibility can
365 ((string= option "--noprogrammer")
366 (warn "treating deprecated --noprogrammer as --disable-debugger")
368 (push "(|DISABLE-DEBUGGER|)" reversed-evals))
369 ((string= option "--disable-debugger")
371 (push "(|DISABLE-DEBUGGER|)" reversed-evals))
372 ((string= option "--end-toplevel-options")
376 ;; Anything we don't recognize as a toplevel
377 ;; option must be the start of user-level
378 ;; options.. except that if we encounter
379 ;; "--end-toplevel-options" after we gave up
380 ;; because we didn't recognize an option as a
381 ;; toplevel option, then the option we gave up on
382 ;; must have been an error. (E.g. in
383 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
384 ;; this test will let us detect that the string
385 ;; "--eval(b)" is an error.)
386 (if (find "--end-toplevel-options" options
388 (error "bad toplevel option: ~S" (first options))
390 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
392 ;; Delete all the options that we processed, so that only
393 ;; user-level options are left visible to user code.
394 (setf (rest *posix-argv*) options)
396 ;; Handle initialization files.
397 (/show0 "handling initialization files in TOPLEVEL-INIT")
398 (flet (;; If any of POSSIBLE-INIT-FILE-NAMES names a real file,
399 ;; return its truename.
400 (probe-init-files (&rest possible-init-file-names)
401 (declare (type list possible-init-file-names))
402 (/show0 "entering PROBE-INIT-FILES")
405 (and (stringp x) (probe-file x)))
406 possible-init-file-names)
407 (/show0 "leaving PROBE-INIT-FILES"))))
408 (let* ((sbcl-home (posix-getenv "SBCL_HOME"))
410 (probe-init-files sysinit
411 (concatenate 'string sbcl-home "/sbclrc")
413 (user-home (or (posix-getenv "HOME")
414 (error "The HOME environment variable is unbound, ~
415 so user init file can't be found.")))
416 (userinit-truename (probe-init-files userinit
421 ;; We wrap all the pre-REPL user/system customized startup code
424 ;; (Why not wrap everything, even the stuff above, in this
425 ;; restart? Errors above here are basically command line or
426 ;; Unix environment errors, e.g. a missing file or a typo on
427 ;; the Unix command line, and you don't need to get into Lisp
428 ;; to debug them, you should just start over and do it right
429 ;; at the Unix level. Errors below here are generally errors
430 ;; in user Lisp code, and it might be helpful to let the user
431 ;; reach the REPL in order to help figure out what's going
435 (flet ((process-init-file (truename)
437 (unless (load truename)
438 (error "~S was not successfully loaded." truename))
439 (flush-standard-output-streams))))
440 (process-init-file sysinit-truename)
441 (process-init-file userinit-truename))
443 ;; Process --eval options.
444 (/show0 "handling --eval options in TOPLEVEL-INIT")
445 (dolist (expr-as-string (reverse reversed-evals))
446 (/show0 "handling one --eval option in TOPLEVEL-INIT")
447 (let ((expr (with-input-from-string (eval-stream
449 (let* ((eof-marker (cons :eof :eof))
450 (result (read eval-stream nil eof-marker))
451 (eof (read eval-stream nil eof-marker)))
452 (cond ((eq result eof-marker)
453 (error "unable to parse ~S"
455 ((not (eq eof eof-marker))
456 (error "more than one expression in ~S"
461 (flush-standard-output-streams))))
464 "Continue anyway (skipping to toplevel read/eval/print loop)."
465 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
466 (values)) ; (no-op, just fall through)
468 :report "Quit SBCL (calling #'QUIT, killing the process)."
469 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
472 ;; one more time for good measure, in case we fell out of the
473 ;; RESTART-CASE above before one of the flushes in the ordinary
474 ;; flow of control had a chance to operate
475 (flush-standard-output-streams)
477 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
478 (toplevel-repl noprint)
479 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
480 (critically-unreachable "after TOPLEVEL-REPL"))))
482 ;;; hooks to support customized toplevels like ACL-style toplevel from
483 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
484 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
485 (defvar *repl-read-form-fun* #'repl-read-form-fun
486 "a function of two stream arguments IN and OUT for the toplevel REPL to
487 call: Return the next Lisp form to evaluate (possibly handling other
488 magic -- like ACL-style keyword commands -- which precede the next
489 Lisp form). The OUT stream is there to support magic which requires
490 issuing new prompts.")
491 (defvar *repl-prompt-fun* #'repl-prompt-fun
492 "a function of one argument STREAM for the toplevel REPL to call: Prompt
493 the user for input.")
494 (defvar *repl-fun-generator* (constantly #'repl-fun)
495 "a function of no arguments returning a function of one argument
496 NOPRINT that provides the REPL for the system. Assumes that
497 *STANDARD-INPUT* and *STANDARD-OUTPUT* are set up.")
499 ;;; read-eval-print loop for the default system toplevel
500 (defun toplevel-repl (noprint)
501 (/show0 "entering TOPLEVEL-REPL")
502 (let ((* nil) (** nil) (*** nil)
504 (+ nil) (++ nil) (+++ nil)
505 (/// nil) (// nil) (/ nil))
506 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
507 (let ((repl-fun (funcall *repl-fun-generator*)))
508 ;; Each REPL in a multithreaded world should have bindings of
509 ;; most CL specials (most critically *PACKAGE*).
510 (with-rebound-io-syntax
511 ;; WITH-SIMPLE-RESTART doesn't actually restart its body as
512 ;; some (like WHN for an embarrassingly long time
513 ;; ca. 2001-12-07) might think, but instead drops control back
514 ;; out at the end. So when a TOPLEVEL or outermost-ABORT
515 ;; restart happens, we need this outer LOOP wrapper to grab
516 ;; control and start over again. (And it also wraps CATCH
517 ;; 'TOPLEVEL-CATCHER for similar reasons.)
519 (/show0 "about to set up restarts in TOPLEVEL-REPL")
520 ;; There should only be one TOPLEVEL restart, and it's here,
521 ;; so restarting at TOPLEVEL always bounces you all the way
523 (with-simple-restart (toplevel
524 "Restart at toplevel READ/EVAL/PRINT loop.")
525 ;; We add a new ABORT restart for every debugger level, so
526 ;; restarting at ABORT in a nested debugger gets you out to
527 ;; the innermost enclosing debugger, and only when you're
528 ;; in the outermost, unnested debugger level does
529 ;; restarting at ABORT get you out to here.
532 "~@<Reduce debugger level (leaving debugger, returning to toplevel).~@:>")
533 (catch 'toplevel-catcher
534 (sb!unix::reset-signal-mask)
535 ;; In the event of a control-stack-exhausted-error, we
536 ;; should have unwound enough stack by the time we get
537 ;; here that this is now possible.
538 (sb!kernel::protect-control-stack-guard-page 1)
539 (funcall repl-fun noprint)
540 (critically-unreachable "after REPL")))))))))
542 ;;; Our default REPL prompt is the minimal traditional one.
543 (defun repl-prompt-fun (stream)
545 (write-string "* " stream)) ; arbitrary but customary REPL prompt
547 ;;; Our default form reader does relatively little magic, but does
548 ;;; handle the Unix-style EOF-is-end-of-process convention.
549 (defun repl-read-form-fun (in out)
550 (declare (type stream in out) (ignore out))
551 (let* ((eof-marker (cons nil nil))
552 (form (read in nil eof-marker)))
553 (if (eq form eof-marker)
557 (defun repl-fun (noprint)
558 (/show0 "entering REPL")
560 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
561 (scrub-control-stack)
562 (sb!thread::get-foreground)
564 (funcall *repl-prompt-fun* *standard-output*)
565 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
566 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
567 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
568 ;; odd. But maybe there *is* a valid reason in some
569 ;; circumstances? perhaps some deadlock issue when being driven
570 ;; by another process or something...)
571 (force-output *standard-output*))
572 (let* ((form (funcall *repl-read-form-fun*
575 (results (multiple-value-list (interactive-eval form))))
577 (dolist (result results)
581 ;;; a convenient way to get into the assembly-level debugger
583 (%primitive sb!c:halt))