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;;;; stuff related to the toplevel read-eval-print loop, plus some
;;;; other miscellaneous functions that we don't have any better place
;;;; for
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
(in-package "SB!IMPL")
;;;; magic specials initialized by GENESIS
;;; FIXME: The DEFVAR here is redundant with the (DECLAIM (SPECIAL ..))
;;; of all static symbols in early-impl.lisp.
(progn
(defvar *current-catch-block*)
(defvar *current-unwind-protect-block*)
(defvar *free-interrupt-context-index*))
;;; specials initialized by !COLD-INIT
;;; FIXME: These could be converted to DEFVARs.
(declaim (special *gc-inhibit* *need-to-collect-garbage*
*before-gc-hooks* *after-gc-hooks*
#!+x86 *pseudo-atomic-atomic*
#!+x86 *pseudo-atomic-interrupted*
sb!unix::*interrupts-enabled*
sb!unix::*interrupt-pending*
*type-system-initialized*))
(defvar *cold-init-complete-p*)
;;; counts of nested errors (with internal errors double-counted)
(defvar *maximum-error-depth*)
(defvar *current-error-depth*)
;;;; miscellaneous utilities for working with with TOPLEVEL
;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
;;; by QUIT) is caught and any final processing and return codes are
;;; handled appropriately.
(defmacro handling-end-of-the-world (&body body)
(with-unique-names (caught)
`(let ((,caught (catch '%end-of-the-world
(/show0 "inside CATCH '%END-OF-THE-WORLD")
,@body)))
(/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
(flush-standard-output-streams)
(/show0 "calling UNIX-EXIT")
(sb!unix:unix-exit ,caught))))
;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
;;; of hyperspace.
(defmacro infinite-error-protect (&rest forms)
`(unless (infinite-error-protector)
(/show0 "back from INFINITE-ERROR-PROTECTOR")
(let ((*current-error-depth* (1+ *current-error-depth*)))
(/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
;; arbitrary truncation
#!+sb-show (sb!debug:backtrace 8)
,@forms)))
;;; a helper function for INFINITE-ERROR-PROTECT
(defun infinite-error-protector ()
(/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
(/hexstr *current-error-depth*)
(cond ((not *cold-init-complete-p*)
(%primitive print "Argh! error in cold init, halting")
(%primitive sb!c:halt))
((or (not (boundp '*current-error-depth*))
(not (realp *current-error-depth*))
(not (boundp '*maximum-error-depth*))
(not (realp *maximum-error-depth*)))
(%primitive print "Argh! corrupted error depth, halting")
(%primitive sb!c:halt))
((> *current-error-depth* *maximum-error-depth*)
(/show0 "*MAXIMUM-ERROR-DEPTH*=..")
(/hexstr *maximum-error-depth*)
(/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
(error-error "Help! "
*current-error-depth*
" nested errors. "
"SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
t)
(t
(/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
nil)))
;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
;;; one point (shown below), and SBCL cross-compiled it without
;;; warning about FORMS being undefined. Check whether that problem
;;; (missing warning) is repeatable in the final system and if so, fix
;;; it.
#|
(defun infinite-error-protector ()
`(cond ((not *cold-init-complete-p*)
(%primitive print "Argh! error in cold init, halting")
(%primitive sb!c:halt))
((or (not (boundp '*current-error-depth*))
(not (realp *current-error-depth*))
(not (boundp '*maximum-error-depth*))
(not (realp *maximum-error-depth*)))
(%primitive print "Argh! corrupted error depth, halting")
(%primitive sb!c:halt))
((> *current-error-depth* *maximum-error-depth*)
(/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
(error-error "Help! "
*current-error-depth*
" nested errors. "
"SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
(progn ,@forms)
t)
(t
(/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
nil)))
|#
;;;; miscellaneous external functions
(defun sleep (n)
#!+sb-doc
"This function causes execution to be suspended for N seconds. N may
be any non-negative, non-complex number."
(when (or (not (realp n))
(minusp n))
(error 'simple-type-error
:format-control "invalid argument to SLEEP: ~S"
:format-arguments (list n)
:datum n
:expected-type '(real 0)))
(multiple-value-bind (sec usec)
(if (integerp n)
(values n 0)
(multiple-value-bind (sec frac)
(truncate n)
(values sec (truncate frac 1e-6))))
(sb!unix:unix-select 0 0 0 0 sec usec))
nil)
;;;; SCRUB-CONTROL-STACK
(defconstant bytes-per-scrub-unit 2048)
;;; Zero the unused portion of the control stack so that old objects
;;; are not kept alive because of uninitialized stack variables.
;;; "To summarize the problem, since not all allocated stack frame
;;; slots are guaranteed to be written by the time you call an another
;;; function or GC, there may be garbage pointers retained in your
;;; dead stack locations. The stack scrubbing only affects the part
;;; of the stack from the SP to the end of the allocated stack."
;;; - ram, on cmucl-imp, Tue, 25 Sep 2001
;;; So, as an (admittedly lame) workaround, from time to time we call
;;; scrub-control-stack to zero out all the unused portion. This is
;;; supposed to happen when the stack is mostly empty, so that we have
;;; a chance of clearing more of it: callers are currently (2002.07.18)
;;; REPL and SUB-GC
(defun scrub-control-stack ()
(declare (optimize (speed 3) (safety 0))
(values (unsigned-byte 20))) ; FIXME: DECLARE VALUES?
#!-stack-grows-downward-not-upward
(let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
(initial-offset (logand csp (1- bytes-per-scrub-unit)))
(end-of-stack
(- (sb!vm:fixnumize sb!vm:*control-stack-end*)
sb!c:*backend-page-size*)))
(labels
((scrub (ptr offset count)
(declare (type system-area-pointer ptr)
(type (unsigned-byte 16) offset)
(type (unsigned-byte 20) count)
(values (unsigned-byte 20)))
(cond ((>= (sap-int ptr) end-of-stack) 0)
((= offset bytes-per-scrub-unit)
(look (sap+ ptr bytes-per-scrub-unit) 0 count))
(t
(setf (sap-ref-32 ptr offset) 0)
(scrub ptr (+ offset sb!vm:n-word-bytes) count))))
(look (ptr offset count)
(declare (type system-area-pointer ptr)
(type (unsigned-byte 16) offset)
(type (unsigned-byte 20) count)
(values (unsigned-byte 20)))
(cond ((>= (sap-int ptr) end-of-stack) 0)
((= offset bytes-per-scrub-unit)
count)
((zerop (sap-ref-32 ptr offset))
(look ptr (+ offset sb!vm:n-word-bytes) count))
(t
(scrub ptr offset (+ count sb!vm:n-word-bytes))))))
(declare (type (unsigned-byte 32) csp))
(scrub (int-sap (- csp initial-offset))
(* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
0)))
#!+stack-grows-downward-not-upward
(let* ((csp (sap-int (sb!c::control-stack-pointer-sap)))
(end-of-stack (+ (sb!vm:fixnumize sb!vm:*control-stack-start*)
sb!c:*backend-page-size*))
(initial-offset (logand csp (1- bytes-per-scrub-unit))))
(labels
((scrub (ptr offset count)
(declare (type system-area-pointer ptr)
(type (unsigned-byte 16) offset)
(type (unsigned-byte 20) count)
(values (unsigned-byte 20)))
(let ((loc (int-sap (- (sap-int ptr) (+ offset sb!vm:n-word-bytes)))))
(cond ((< (sap-int loc) end-of-stack) 0)
((= offset bytes-per-scrub-unit)
(look (int-sap (- (sap-int ptr) bytes-per-scrub-unit))
0 count))
(t ;; need to fix bug in %SET-STACK-REF
(setf (sap-ref-32 loc 0) 0)
(scrub ptr (+ offset sb!vm:n-word-bytes) count)))))
(look (ptr offset count)
(declare (type system-area-pointer ptr)
(type (unsigned-byte 16) offset)
(type (unsigned-byte 20) count)
(values (unsigned-byte 20)))
(let ((loc (int-sap (- (sap-int ptr) offset))))
(cond ((< (sap-int loc) end-of-stack) 0)
((= offset bytes-per-scrub-unit)
count)
((zerop (sb!kernel::get-lisp-obj-address (stack-ref loc 0)))
(look ptr (+ offset sb!vm:n-word-bytes) count))
(t
(scrub ptr offset (+ count sb!vm:n-word-bytes)))))))
(declare (type (unsigned-byte 32) csp))
(scrub (int-sap (+ csp initial-offset))
(* (floor initial-offset sb!vm:n-word-bytes) sb!vm:n-word-bytes)
0))))
;;;; the default toplevel function
(defvar / nil
#!+sb-doc
"a list of all the values returned by the most recent top level EVAL")
(defvar // nil #!+sb-doc "the previous value of /")
(defvar /// nil #!+sb-doc "the previous value of //")
(defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
(defvar ** nil #!+sb-doc "the previous value of *")
(defvar *** nil #!+sb-doc "the previous value of **")
(defvar + nil #!+sb-doc "the value of the most recent top level READ")
(defvar ++ nil #!+sb-doc "the previous value of +")
(defvar +++ nil #!+sb-doc "the previous value of ++")
(defvar - nil #!+sb-doc "the form currently being evaluated")
(defun interactive-eval (form)
"Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
+++, ++, +, ///, //, /, and -."
(setf - form)
(let ((results
(multiple-value-list
(eval-in-lexenv form
(make-null-interactive-lexenv)))))
(setf /// //
// /
/ results
*** **
** *
* (car results)))
(setf +++ ++
++ +
+ -)
(unless (boundp '*)
;; The bogon returned an unbound marker.
;; FIXME: It would be safer to check every one of the values in RESULTS,
;; instead of just the first one.
(setf * nil)
(cerror "Go on with * set to NIL."
"EVAL returned an unbound marker."))
(values-list /))
;;; Flush anything waiting on one of the ANSI Common Lisp standard
;;; output streams before proceeding.
(defun flush-standard-output-streams ()
(dolist (name '(*debug-io*
*error-output*
*query-io*
*standard-output*
*trace-output*))
(finish-output (symbol-value name)))
(values))
;;; the default system top level function
(defun toplevel-init ()
(/show0 "entering TOPLEVEL-INIT")
(setf sb!thread::*session-lock* (sb!thread:make-mutex :name "the terminal"))
(sb!thread::get-foreground)
(let (;; value of --sysinit option
(sysinit nil)
;; value of --userinit option
(userinit nil)
;; values of --eval options, in reverse order; and also any
;; other options (like --load) which're translated into --eval
;;
;; The values are stored as strings, so that they can be
;; passed to READ only after their predecessors have been
;; EVALed, so that things work when e.g. REQUIRE in one EVAL
;; form creates a package referred to in the next EVAL form.
(reversed-evals nil)
;; Has a --noprint option been seen?
(noprint nil)
;; everything in *POSIX-ARGV* except for argv[0]=programname
(options (rest *posix-argv*)))
(declare (type list options))
(/show0 "done with outer LET in TOPLEVEL-INIT")
;; FIXME: There are lots of ways for errors to happen around here
;; (e.g. bad command line syntax, or READ-ERROR while trying to
;; READ an --eval string). Make sure that they're handled
;; reasonably. Also, perhaps all errors while parsing the command
;; line should cause the system to QUIT, instead of trying to go
;; into the Lisp debugger, since trying to go into the debugger
;; gets into various annoying issues of where we should go after
;; the user tries to return from the debugger.
;; Parse command line options.
(loop while options do
(/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
(let ((option (first options)))
(flet ((pop-option ()
(if options
(pop options)
(error "unexpected end of command line options"))))
(cond ((string= option "--sysinit")
(pop-option)
(if sysinit
(error "multiple --sysinit options")
(setf sysinit (pop-option))))
((string= option "--userinit")
(pop-option)
(if userinit
(error "multiple --userinit options")
(setf userinit (pop-option))))
((string= option "--eval")
(pop-option)
(push (pop-option) reversed-evals))
((string= option "--load")
(pop-option)
(push
;; FIXME: see BUG 296
(concatenate 'string "(|LOAD| \"" (pop-option) "\")")
reversed-evals))
((string= option "--noprint")
(pop-option)
(setf noprint t))
;; FIXME: --noprogrammer was deprecated in 0.7.5, and
;; in a year or so this backwards compatibility can
;; go away.
((string= option "--noprogrammer")
(warn "treating deprecated --noprogrammer as --disable-debugger")
(pop-option)
(push "(|DISABLE-DEBUGGER|)" reversed-evals))
((string= option "--disable-debugger")
(pop-option)
(push "(|DISABLE-DEBUGGER|)" reversed-evals))
((string= option "--end-toplevel-options")
(pop-option)
(return))
(t
;; Anything we don't recognize as a toplevel
;; option must be the start of user-level
;; options.. except that if we encounter
;; "--end-toplevel-options" after we gave up
;; because we didn't recognize an option as a
;; toplevel option, then the option we gave up on
;; must have been an error. (E.g. in
;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
;; this test will let us detect that the string
;; "--eval(b)" is an error.)
(if (find "--end-toplevel-options" options
:test #'string=)
(error "bad toplevel option: ~S" (first options))
(return)))))))
(/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
;; Delete all the options that we processed, so that only
;; user-level options are left visible to user code.
(setf (rest *posix-argv*) options)
;; Handle initialization files.
(/show0 "handling initialization files in TOPLEVEL-INIT")
(flet (;; If any of POSSIBLE-INIT-FILE-NAMES names a real file,
;; return its truename.
(probe-init-files (&rest possible-init-file-names)
(declare (type list possible-init-file-names))
(/show0 "entering PROBE-INIT-FILES")
(prog1
(find-if (lambda (x)
(and (stringp x) (probe-file x)))
possible-init-file-names)
(/show0 "leaving PROBE-INIT-FILES"))))
(let* ((sbcl-home (posix-getenv "SBCL_HOME"))
(sysinit-truename (if sbcl-home
(probe-init-files sysinit
(concatenate 'string
sbcl-home
"/sbclrc"))
(probe-init-files sysinit
"/etc/sbclrc"
"/usr/local/etc/sbclrc")))
(user-home (or (posix-getenv "HOME")
(error "The HOME environment variable is unbound, ~
so user init file can't be found.")))
(userinit-truename (probe-init-files userinit
(concatenate 'string
user-home
"/.sbclrc"))))
;; We wrap all the pre-REPL user/system customized startup code
;; in a restart.
;;
;; (Why not wrap everything, even the stuff above, in this
;; restart? Errors above here are basically command line or
;; Unix environment errors, e.g. a missing file or a typo on
;; the Unix command line, and you don't need to get into Lisp
;; to debug them, you should just start over and do it right
;; at the Unix level. Errors below here are generally errors
;; in user Lisp code, and it might be helpful to let the user
;; reach the REPL in order to help figure out what's going
;; on.)
(restart-case
(progn
(flet ((process-init-file (truename)
(when truename
(unless (load truename)
(error "~S was not successfully loaded." truename))
(flush-standard-output-streams))))
(process-init-file sysinit-truename)
(process-init-file userinit-truename))
;; Process --eval options.
(/show0 "handling --eval options in TOPLEVEL-INIT")
(dolist (expr-as-string (reverse reversed-evals))
(/show0 "handling one --eval option in TOPLEVEL-INIT")
(let ((expr (with-input-from-string (eval-stream
expr-as-string)
(let* ((eof-marker (cons :eof :eof))
(result (read eval-stream nil eof-marker))
(eof (read eval-stream nil eof-marker)))
(cond ((eq result eof-marker)
(error "unable to parse ~S"
expr-as-string))
((not (eq eof eof-marker))
(error "more than one expression in ~S"
expr-as-string))
(t
result))))))
(eval expr)
(flush-standard-output-streams))))
(continue ()
:report
"Continue anyway (skipping to toplevel read/eval/print loop)."
(/show0 "CONTINUEing from pre-REPL RESTART-CASE")
(values)) ; (no-op, just fall through)
(quit ()
:report "Quit SBCL (calling #'QUIT, killing the process)."
(/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
(quit))))
;; one more time for good measure, in case we fell out of the
;; RESTART-CASE above before one of the flushes in the ordinary
;; flow of control had a chance to operate
(flush-standard-output-streams)
(/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
(toplevel-repl noprint)
;; (classic CMU CL error message: "You're certainly a clever child.":-)
(critically-unreachable "after TOPLEVEL-REPL"))))
;;; read-eval-print loop for the default system toplevel
(defun toplevel-repl (noprint)
(/show0 "entering TOPLEVEL-REPL")
(let ((* nil) (** nil) (*** nil)
(- nil)
(+ nil) (++ nil) (+++ nil)
(/// nil) (// nil) (/ nil))
;; WITH-SIMPLE-RESTART doesn't actually restart its body as some
;; (like WHN for an embarrassingly long time ca. 2001-12-07) might
;; think, but instead drops control back out at the end. So when a
;; TOPLEVEL or outermost-ABORT restart happens, we need this outer
;; LOOP wrapper to grab control and start over again. (And it also
;; wraps CATCH 'TOPLEVEL-CATCHER for similar reasons.)
(loop
(/show0 "about to set up restarts in TOPLEVEL-REPL")
;; There should only be one TOPLEVEL restart, and it's here, so
;; restarting at TOPLEVEL always bounces you all the way out here.
(with-simple-restart (toplevel
"Restart at toplevel READ/EVAL/PRINT loop.")
;; We add a new ABORT restart for every debugger level, so
;; restarting at ABORT in a nested debugger gets you out to the
;; innermost enclosing debugger, and only when you're in the
;; outermost, unnested debugger level does restarting at ABORT
;; get you out to here.
(with-simple-restart
(abort
"~@<Reduce debugger level (leaving debugger, returning to toplevel).~@:>")
(catch 'toplevel-catcher
#!-sunos (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
;; in the event of a control-stack-exhausted-error, we should
;; have unwound enough stack by the time we get here that this
;; is now possible
(sb!kernel::protect-control-stack-guard-page 1)
(funcall *repl-fun* noprint)
(critically-unreachable "after REPL")))))))
;;; Our default REPL prompt is the minimal traditional one.
(defun repl-prompt-fun (stream)
(fresh-line stream)
(write-string "* " stream)) ; arbitrary but customary REPL prompt
;;; Our default form reader does relatively little magic, but does
;;; handle the Unix-style EOF-is-end-of-process convention.
(defun repl-read-form-fun (in out)
(declare (type stream in out) (ignore out))
(let* ((eof-marker (cons nil nil))
(form (read in nil eof-marker)))
(if (eq form eof-marker)
(quit)
form)))
;;; hooks to support customized toplevels like ACL-style toplevel
;;; from KMR on sbcl-devel 2002-12-21
(defvar *repl-read-form-fun* #'repl-read-form-fun
"a function of two stream arguments IN and OUT for the toplevel REPL to
call: Return the next Lisp form to evaluate (possibly handling other
magic -- like ACL-style keyword commands -- which precede the next
Lisp form). The OUT stream is there to support magic which requires
issuing new prompts.")
(defvar *repl-prompt-fun* #'repl-prompt-fun
"a function of one argument STREAM for the toplevel REPL to call: Prompt
the user for input.")
(defvar *repl-fun* #'repl-fun
"a function of one argument NOPRINT that provides the REPL for the system.
Assumes that *standard-input* and *standard-output* are setup.")
(defun repl-fun (noprint)
(/show0 "entering REPL")
(loop
;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
(scrub-control-stack)
(unless noprint
(funcall *repl-prompt-fun* *standard-output*)
;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
;; odd. But maybe there *is* a valid reason in some
;; circumstances? perhaps some deadlock issue when being driven
;; by another process or something...)
(force-output *standard-output*))
(let* ((form (funcall *repl-read-form-fun*
*standard-input*
*standard-output*))
(results (multiple-value-list (interactive-eval form))))
(unless noprint
(dolist (result results)
(fresh-line)
(prin1 result))))))
;;; a convenient way to get into the assembly-level debugger
(defun %halt ()
(%primitive sb!c:halt))