gash/gash/built-ins/trap.scm

68 lines
2.2 KiB
Scheme

;;; Gash -- Guile As SHell
;;; Copyright © 2018 Timothy Sample <samplet@ngyro.com>
;;;
;;; This file is part of Gash.
;;;
;;; Gash is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation, either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; Gash is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with Gash. If not, see <http://www.gnu.org/licenses/>.
(define-module (gash built-ins trap)
#:use-module (gash environment)
#:use-module (ice-9 match))
;;; Commentary:
;;;
;;; The 'trap' utility.
;;;
;;; Code:
(define sh:eval (@@ (gash built-ins eval) main))
(define (action->handler action)
(let ((n (string->number action)))
(cond
((and n (integer? n) (>= n 0)) SIG_DFL)
((string=? action "-") SIG_DFL)
((string-null? action) SIG_IGN)
(else (lambda () (sh:eval action))))))
(define (condition->signum condition)
(let ((n (string->number condition)))
(cond
((and n (integer? n)) n)
((string-ci=? condition "EXIT") 0)
(else (let* ((name (if (string-prefix-ci? "SIG" condition)
(string-upcase condition)
(string-append "SIG" (string-upcase condition))))
(symb (string->symbol name)))
(or (and=> (module-variable (current-module) symb)
variable-ref)
-1))))))
(define (main . args)
(match args
(() "print")
(("--" . args) (main args))
((action conditions ..1)
(let ((handler (action->handler action)))
(for-each (lambda (condition)
(match (condition->signum condition)
(0 (set-atexit! handler))
(n (sigaction n handler))))
conditions))
EXIT_SUCCESS)
(_ (format (current-error-port)
"~a: trap: Invalid options ~s.~%"
(car (program-arguments)) args)
EXIT_FAILURE)))