169 lines
5.3 KiB
Scheme
169 lines
5.3 KiB
Scheme
;;; The signal-handling code in the last half of this file is obsolete. 8/23/96
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;;; Copyright (c) 1993 by Olin Shivers.
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;;; Job control code.
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(foreign-source
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"#include <sys/signal.h>"
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"#include <sys/types.h>"
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"#include <unistd.h>"
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""
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"extern int errno;"
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""
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"#define errno_or_false(x) (((x) == -1) ? ENTER_FIXNUM(errno) : SCHFALSE)"
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"" "")
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;;; Fork off a process that runs in its own process group. The process is
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;;; placed in its own process group before the process's actual work code is
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;;; executed. We block ^Z's until we've got the child into its own proc group.
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(define (fork-job . maybe-thunk)
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(flush-all-ports)
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((with-blocked-interrupts (bitwise-ior (blocked-interrupts) ; Block ^Z.
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(interrupt-set signal/tstp))
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(cond ((%fork) => (lambda (child) (lambda () child))) ; Parent
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(else ; Child
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(set-process-group (pid)) ; Put ourselves in our own proc group.
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(if (not (interrupt-handler signal/tstp)) ; If ignoring TSTP,
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(set-interrupt-handler signal/tstp #t)) ; reset to default.
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(set-batch-mode?! #t) ; Batch mode.
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(lambda () (and (pair? maybe-thunk) ; Release ^Z & do it.
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(call-terminally (car maybe-thunk)))))))))
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;;; Foreground a suspended or running background job.
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(define (foreground-job proc-group)
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(let ((iport (current-input-port)))
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(cond ((and (not (batch-mode?)) (is-control-tty? iport))
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(dynamic-wind
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(lambda () (set-tty-process-group iport proc-group))
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(lambda ()
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(signal-process-group proc-group signal/cont) ; You go;
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(wait proc-group wait/stopped-children)) ; I'll wait.
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(lambda ()
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(with-blocked-interrupts
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(bitwise-ior (blocked-interrupts)
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(interrupt-set signal/ttou))
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(set-tty-process-group iport (process-group))))))
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;; Oops, not really doing job control -- just wait on the process.
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(else (signal-process proc-group signal/cont) ; You go;
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(wait proc-group wait/stopped-children))))) ; I'll wait.
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;;; Background a suspended job.
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(define (background-job proc-group)
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(signal-process-group proc-group signal/cont))
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(define-simple-syntax (run . epf)
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(foreground-job (& . epf)))
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(define-simple-syntax (& . epf)
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(fork-job (lambda () (exec-epf . epf))))
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;;; Need repl loop that manages some kind of a job table.
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;;; Interactive startup must ignore ^Z.
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(define *control-tty-fdes* #f)
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(define (control-tty-fdes)
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(or *control-tty-fdes*
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(begin (set! *control-tty-fdes*
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(with-errno-handler ((errno data) (else #f))
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(open-fdes "/dev/tty" open/read)))
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*control-tty-fdes*)))
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(define (is-control-tty? fd/port)
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(with-errno-handler ((errno data) (else #f)) ; False if you fail.
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(tty-process-group fd/port))) ; Try it.
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;;; Blocking interrupts
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define (interrupt-set . interrupts)
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(let lp ((ints interrupts) (ans 0))
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(if (pair? ints)
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(lp (cdr ints) (bitwise-ior ans (arithmetic-shift 1 (- (car ints) 1))))
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ans)))
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(define-simple-syntax (with-blocked-interrupts mask body ...)
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(with-blocked-interrupts* mask (lambda () body ...)))
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(define (with-blocked-interrupts* mask thunk)
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(let ((old-mask #f))
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(dynamic-wind
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(lambda () (set! old-mask (set-blocked-interrupts mask)))
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thunk
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(lambda () (set-blocked-interrupts old-mask)))))
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(define (set-blocked-interrupts mask)
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(receive (hi-out lo-out)
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(%set-blocked-interrupts (hi8 mask) (lo24 mask))
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(compose-8/24 hi-out lo-out)))
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(define (blocked-interrupts)
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(call-with-values %blocked-interrupts compose-8/24))
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(define-foreign %set-blocked-interrupts (set_procmask (fixnum hi)
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(fixnum lo))
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fixnum ; hi
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fixnum) ; lo
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(define-foreign %blocked-interrupts (get_procmask)
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fixnum ; hi
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fixnum) ; lo
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;;; Get/Set interrupt handlers
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; I'm punting the MASK value for now.
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;;; I'm also punting returning real Scheme handlers for now.
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(define (set-interrupt-handler interrupt handler)
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(receive (handler flags) ; Should be (handler mask flags).
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(%set-interrupt-handler interrupt handler 0)
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handler))
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(define (interrupt-handler interrupt)
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(receive (handler flags) (%interrupt-handler interrupt)
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handler))
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(define (%interrupt-handler interrupt)
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(receive (err handler flags) (%%interrupt-handler interrupt)
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(if err (errno-error err interrupt-handler interrupt)
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(process-interrupt-handler-retvals handler flags))))
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;;; (%set-interrupt-handler interrupt handler [mask flags]) -> [handler mask flags]
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;;; Except no MASK for now.
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(define (%set-interrupt-handler interrupt handler . args)
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(let-optionals args ((flags 0))
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(receive (err handler flags)
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(%%set-interrupt-handler interrupt handler flags)
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(if err
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(errno-error err %set-interrupt-handler interrupt handler flags)
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(process-interrupt-handler-retvals handler flags)))))
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(define-foreign %%set-interrupt-handler (set_int_handler (fixnum signal)
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(desc handler)
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(fixnum flags))
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desc ; #f or errno
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desc ; handler
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fixnum) ; flags
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(define-foreign %%interrupt-handler (get_int_handler (fixnum signal))
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desc ; #f or errno
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desc ; handler
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fixnum) ; flags
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(define (process-interrupt-handler-retvals handler flags)
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(values (if (integer? handler)
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(error "We don't do Scheme handlers yet.")
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handler)
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flags))
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