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* *already-maybe-gcing*
29 *need-to-collect-garbage*
31 *before-gc-hooks* *after-gc-hooks*
32 #!+x86 *pseudo-atomic-atomic*
33 #!+x86 *pseudo-atomic-interrupted*
34 sb!unix::*interrupts-enabled*
35 sb!unix::*interrupt-pending*
36 *type-system-initialized*))
38 (defvar *cold-init-complete-p*)
40 ;;; counts of nested errors (with internal errors double-counted)
41 (defvar *maximum-error-depth*)
42 (defvar *current-error-depth*)
44 ;;;; miscellaneous utilities for working with with TOPLEVEL
46 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
47 ;;; by QUIT) is caught and any final processing and return codes are
48 ;;; handled appropriately.
49 (defmacro handling-end-of-the-world (&body body)
50 (let ((caught (gensym "CAUGHT")))
51 `(let ((,caught (catch '%end-of-the-world
52 (/show0 "inside CATCH '%END-OF-THE-WORLD")
54 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
55 (flush-standard-output-streams)
56 (/show0 "calling UNIX-EXIT")
57 (sb!unix:unix-exit ,caught))))
59 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
61 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
63 (defmacro infinite-error-protect (&rest forms)
64 `(unless (infinite-error-protector)
65 (/show0 "back from INFINITE-ERROR-PROTECTOR")
66 (let ((*current-error-depth* (1+ *current-error-depth*)))
67 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
68 #+sb-show (sb-debug:backtrace)
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 "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 "KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
122 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
126 ;;;; miscellaneous external functions
128 #!-mp ; The multi-processing version is defined in multi-proc.lisp.
131 "This function causes execution to be suspended for N seconds. N may
132 be any non-negative, non-complex number."
133 (when (or (not (realp n))
135 (error 'simple-type-error
136 :format-control "invalid argument to SLEEP: ~S"
137 :format-arguments (list n)
139 :expected-type '(real 0)))
140 (multiple-value-bind (sec usec)
143 (multiple-value-bind (sec frac)
145 (values sec (truncate frac 1e-6))))
146 (sb!unix:unix-select 0 0 0 0 sec usec))
149 ;;;; SCRUB-CONTROL-STACK
151 (defconstant bytes-per-scrub-unit 2048)
153 ;;; Zero the unused portion of the control stack so that old objects
154 ;;; are not kept alive because of uninitialized stack variables.
156 ;;; "To summarize the problem, since not all allocated stack frame
157 ;;; slots are guaranteed to be written by the time you call an another
158 ;;; function or GC, there may be garbage pointers retained in your
159 ;;; dead stack locations. The stack scrubbing only affects the part
160 ;;; of the stack from the SP to the end of the allocated stack."
161 ;;; - ram, on cmucl-imp, Tue, 25 Sep 2001
163 ;;; So, as an (admittedly lame) workaround, from time to time we call
164 ;;; scrub-control-stack to zero out all the unused portion. This is
165 ;;; supposed to happen when the stack is mostly empty, so that we have
166 ;;; a chance of clearing more of it: callers are currently (2002.07.18)
169 (defun scrub-control-stack ()
170 (declare (optimize (speed 3) (safety 0))
171 (values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
173 #!-stack-grows-downward-not-upward
174 (let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
175 (initial-offset (logand csp (1- bytes-per-scrub-unit)))
177 (- sb!vm:control-stack-end 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:control-stack-start sb!c:*backend-page-size*))
210 (initial-offset (logand csp (1- bytes-per-scrub-unit))))
212 ((scrub (ptr offset count)
213 (declare (type system-area-pointer ptr)
214 (type (unsigned-byte 16) offset)
215 (type (unsigned-byte 20) count)
216 (values (unsigned-byte 20)))
217 (let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
218 (cond ((<= (sap-int loc) end-of-stack) 0)
219 ((= offset bytes-per-scrub-unit)
220 (look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
222 (t ;; need to fix bug in %SET-STACK-REF
223 (setf (sap-ref-32 loc 0) 0)
224 (scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
225 (look (ptr offset count)
226 (declare (type system-area-pointer ptr)
227 (type (unsigned-byte 16) offset)
228 (type (unsigned-byte 20) count)
229 (values (unsigned-byte 20)))
230 (let ((loc (int-sap (- (sap-int ptr) offset))))
231 (cond ((<= (sap-int loc) end-of-stack) 0)
232 ((= offset bytes-per-scrub-unit)
234 ((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
235 (look ptr (+ offset sb!vm:n-word-bytes) count))
237 (scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
238 (declare (type (unsigned-byte 32) csp))
239 (scrub (int-sap (+ csp initial-offset))
240 (* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
243 ;;;; the default toplevel function
247 "a list of all the values returned by the most recent top level EVAL")
248 (defvar // nil #!+sb-doc "the previous value of /")
249 (defvar /// nil #!+sb-doc "the previous value of //")
250 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
251 (defvar ** nil #!+sb-doc "the previous value of *")
252 (defvar *** nil #!+sb-doc "the previous value of **")
253 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
254 (defvar ++ nil #!+sb-doc "the previous value of +")
255 (defvar +++ nil #!+sb-doc "the previous value of ++")
256 (defvar - nil #!+sb-doc "the form currently being evaluated")
258 (defun interactive-eval (form)
259 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
260 +++, ++, +, ///, //, /, and -."
262 (let ((results (multiple-value-list (eval form))))
273 ;; The bogon returned an unbound marker.
274 ;; FIXME: It would be safer to check every one of the values in RESULTS,
275 ;; instead of just the first one.
277 (cerror "Go on with * set to NIL."
278 "EVAL returned an unbound marker."))
281 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
282 ;;; output streams before proceeding.
283 (defun flush-standard-output-streams ()
284 (dolist (name '(*debug-io*
289 (finish-output (symbol-value name)))
292 ;;; the default system top level function
293 (defun toplevel-init ()
295 (/show0 "entering TOPLEVEL-INIT")
297 (let ((sysinit nil) ; value of --sysinit option
298 (userinit nil) ; value of --userinit option
299 (reversed-evals nil) ; values of --eval options, in reverse order; and
300 ; also --load options, translated into --eval
301 (noprint nil) ; Has a --noprint option been seen?
302 (options (rest *posix-argv*))) ; skipping program name
304 (/show0 "done with outer LET in TOPLEVEL-INIT")
306 ;; FIXME: There are lots of ways for errors to happen around here
307 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
308 ;; READ an --eval string). Make sure that they're handled
309 ;; reasonably. Also, perhaps all errors while parsing the command
310 ;; line should cause the system to QUIT, instead of trying to go
311 ;; into the Lisp debugger, since trying to go into the debugger
312 ;; gets into various annoying issues of where we should go after
313 ;; the user tries to return from the debugger.
315 ;; Parse command line options.
316 (loop while options do
317 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
318 (let ((option (first options)))
319 (flet ((pop-option ()
322 (error "unexpected end of command line options"))))
323 (cond ((string= option "--sysinit")
326 (error "multiple --sysinit options")
327 (setf sysinit (pop-option))))
328 ((string= option "--userinit")
331 (error "multiple --userinit options")
332 (setf userinit (pop-option))))
333 ((string= option "--eval")
335 (let ((eval-as-string (pop-option)))
336 (with-input-from-string (eval-stream eval-as-string)
337 (let* ((eof-marker (cons :eof :eof))
338 (eval (read eval-stream nil eof-marker))
339 (eof (read eval-stream nil eof-marker)))
340 (cond ((eq eval eof-marker)
341 (error "unable to parse ~S"
343 ((not (eq eof eof-marker))
344 (error "more than one expression in ~S"
347 (push eval reversed-evals)))))))
348 ((string= option "--load")
350 (push `(load ,(pop-option)) reversed-evals))
351 ((string= option "--noprint")
354 ;; FIXME: --noprogrammer was deprecated in 0.7.5, and
355 ;; in a year or so this backwards compatibility can
357 ((string= option "--noprogrammer")
358 (warn "treating deprecated --noprogrammer as --disable-debugger")
360 (push '(disable-debugger) reversed-evals))
361 ((string= option "--disable-debugger")
363 (push '(disable-debugger) reversed-evals))
364 ((string= option "--end-toplevel-options")
368 ;; Anything we don't recognize as a toplevel
369 ;; option must be the start of user-level
370 ;; options.. except that if we encounter
371 ;; "--end-toplevel-options" after we gave up
372 ;; because we didn't recognize an option as a
373 ;; toplevel option, then the option we gave up on
374 ;; must have been an error. (E.g. in
375 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
376 ;; this test will let us detect that the string
377 ;; "--eval(b)" is an error.)
378 (if (find "--end-toplevel-options" options
380 (error "bad toplevel option: ~S" (first options))
382 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
384 ;; Excise all the options that we processed, so that only
385 ;; user-level options are left visible to user code.
386 (setf (rest *posix-argv*) options)
388 ;; Handle initialization files.
389 (/show0 "handling initialization files in TOPLEVEL-INIT")
390 (flet (;; If any of POSSIBLE-INIT-FILE-NAMES names a real file,
391 ;; return its truename.
392 (probe-init-files (&rest possible-init-file-names)
393 (/show0 "entering PROBE-INIT-FILES")
396 (and (stringp x) (probe-file x)))
397 possible-init-file-names)
398 (/show0 "leaving PROBE-INIT-FILES"))))
399 (let* ((sbcl-home (posix-getenv "SBCL_HOME"))
400 (sysinit-truename (if sbcl-home
401 (probe-init-files sysinit
405 (probe-init-files sysinit
407 "/usr/local/etc/sbclrc")))
408 (user-home (or (posix-getenv "HOME")
409 (error "The HOME environment variable is unbound, ~
410 so user init file can't be found.")))
411 (userinit-truename (probe-init-files userinit
416 ;; We wrap all the pre-REPL user/system customized startup code
419 ;; (Why not wrap everything, even the stuff above, in this
420 ;; restart? Errors above here are basically command line or
421 ;; Unix environment errors, e.g. a missing file or a typo on
422 ;; the Unix command line, and you don't need to get into Lisp
423 ;; to debug them, you should just start over and do it right
424 ;; at the Unix level. Errors below here are generally errors
425 ;; in user Lisp code, and it might be helpful to let the user
426 ;; reach the REPL in order to help figure out what's going
430 (flet ((process-init-file (truename)
432 (unless (load truename)
433 (error "~S was not successfully loaded." truename))
434 (flush-standard-output-streams))))
435 (process-init-file sysinit-truename)
436 (process-init-file userinit-truename))
438 ;; Process --eval options.
439 (/show0 "handling --eval options in TOPLEVEL-INIT")
440 (dolist (eval (reverse reversed-evals))
441 (/show0 "handling one --eval option in TOPLEVEL-INIT")
443 (flush-standard-output-streams)))
446 "Continue anyway (skipping to toplevel read/eval/print loop)."
447 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
448 (values)) ; (no-op, just fall through)
450 :report "Quit SBCL (calling #'QUIT, killing the process)."
451 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
454 ;; one more time for good measure, in case we fell out of the
455 ;; RESTART-CASE above before one of the flushes in the ordinary
456 ;; flow of control had a chance to operate
457 (flush-standard-output-streams)
459 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
460 (toplevel-repl noprint)
461 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
462 (critically-unreachable "after TOPLEVEL-REPL"))))
464 ;;; halt-on-failures and prompt-on-failures modes, suitable for
465 ;;; noninteractive and interactive use respectively
466 (defun disable-debugger ()
467 (setf *debugger-hook* 'noprogrammer-debugger-hook-fun
468 *debug-io* *error-output*))
469 (defun enable-debugger ()
470 (setf *debugger-hook* nil
471 *debug-io* *query-io*))
473 ;;; read-eval-print loop for the default system toplevel
474 (defun toplevel-repl (noprint)
475 (/show0 "entering TOPLEVEL-REPL")
476 (let ((* nil) (** nil) (*** nil)
478 (+ nil) (++ nil) (+++ nil)
479 (/// nil) (// nil) (/ nil))
480 ;; WITH-SIMPLE-RESTART doesn't actually restart its body as some
481 ;; (like WHN for an embarrassingly long time ca. 2001-12-07) might
482 ;; think, but instead drops control back out at the end. So when a
483 ;; TOPLEVEL or outermost-ABORT restart happens, we need this outer
484 ;; LOOP wrapper to grab control and start over again. (And it also
485 ;; wraps CATCH 'TOPLEVEL-CATCHER for similar reasons.)
487 (/show0 "about to set up restarts in TOPLEVEL-REPL")
488 ;; There should only be one TOPLEVEL restart, and it's here, so
489 ;; restarting at TOPLEVEL always bounces you all the way out here.
490 (with-simple-restart (toplevel
491 "Restart at toplevel READ/EVAL/PRINT loop.")
492 ;; We add a new ABORT restart for every debugger level, so
493 ;; restarting at ABORT in a nested debugger gets you out to the
494 ;; innermost enclosing debugger, and only when you're in the
495 ;; outermost, unnested debugger level does restarting at ABORT
496 ;; get you out to here.
499 "Reduce debugger level (leaving debugger, returning to toplevel).")
500 (catch 'toplevel-catcher
501 #!-sunos (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
502 ;; in the event of a control-stack-exhausted-error, we should
503 ;; have unwound enough stack by the time we get here that this
505 (sb!kernel::protect-control-stack-guard-page 1)
507 (critically-unreachable "after REPL")))))))
509 (defun repl (noprint)
510 (/show0 "entering REPL")
511 (let ((eof-marker (cons :eof nil)))
513 ;; see comment preceding definition of SCRUB-CONTROL-STACK
514 (scrub-control-stack)
517 (write-string "* ") ; arbitrary but customary REPL prompt
518 (flush-standard-output-streams))
519 (let ((form (read *standard-input* nil eof-marker)))
520 (cond ((eq form eof-marker)
521 (/show0 "doing QUIT for EOF in REPL")
524 (let ((results (multiple-value-list (interactive-eval form))))
526 (dolist (result results)
528 (prin1 result))))))))))
530 ;;; suitable value for *DEBUGGER-HOOK* for a noninteractive Unix-y program
531 (defun noprogrammer-debugger-hook-fun (condition old-debugger-hook)
532 (declare (ignore old-debugger-hook))
533 (flet ((failure-quit (&key recklessly-p)
534 (/show0 "in FAILURE-QUIT (in --disable-debugger debugger hook)")
535 (quit :unix-status 1 :recklessly-p recklessly-p)))
536 ;; This HANDLER-CASE is here mostly to stop output immediately
537 ;; (and fall through to QUIT) when there's an I/O error. Thus,
538 ;; when we're run under a shell script or something, we can die
539 ;; cleanly when the script dies (and our pipes are cut), instead
540 ;; of falling into ldb or something messy like that.
543 (format *error-output*
544 "~&~@<unhandled condition (of type ~S): ~2I~_~A~:>~2%"
547 ;; Flush *ERROR-OUTPUT* even before the BACKTRACE, so that
548 ;; even if we hit an error within BACKTRACE (e.g. a bug in
549 ;; the debugger's own frame-walking code, or a bug in a user
550 ;; PRINT-OBJECT method) we'll at least have the CONDITION
551 ;; printed out before we die.
552 (finish-output *error-output*)
553 ;; (Where to truncate the BACKTRACE is of course arbitrary, but
554 ;; it seems as though we should at least truncate it somewhere.)
555 (sb!debug:backtrace 128 *error-output*)
558 "~%unhandled condition in --disable-debugger mode, quitting~%")
559 (finish-output *error-output*)
562 ;; We IGNORE-ERRORS here because even %PRIMITIVE PRINT can
563 ;; fail when our output streams are blown away, as e.g. when
564 ;; we're running under a Unix shell script and it dies somehow
565 ;; (e.g. because of a SIGINT). In that case, we might as well
566 ;; just give it up for a bad job, and stop trying to notify
567 ;; the user of anything.
569 ;; Actually, the only way I've run across to exercise the
570 ;; problem is to have more than one layer of shell script.
571 ;; I have a shell script which does
572 ;; time nice -10 sh make.sh "$1" 2>&1 | tee make.tmp
573 ;; and the problem occurs when I interrupt this with Ctrl-C
574 ;; under Linux 2.2.14-5.0 and GNU bash, version 1.14.7(1).
575 ;; I haven't figured out whether it's bash, time, tee, Linux, or
576 ;; what that is responsible, but that it's possible at all
577 ;; means that we should IGNORE-ERRORS here. -- WHN 2001-04-24
580 "Argh! error within --disable-debugger error handling"))
581 (failure-quit :recklessly-p t)))))
583 ;;; a convenient way to get into the assembly-level debugger
585 (%primitive sb!c:halt))