src/code/target-signal.lisp

   1 ;;;; code for handling UNIX signals
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!UNIX")
  13
  14 (defmacro with-interrupt-bindings (&body body)
  15   (with-unique-names (empty)
  16     `(let*
  17          ;; KLUDGE: Whatever is on the PCL stacks before the interrupt
  18          ;; handler runs doesn't really matter, since we're not on the
  19          ;; same call stack, really -- and if we don't bind these (esp.
  20          ;; the cache one) we can get a bogus metacircle if an interrupt
  21          ;; handler calls a GF that was being computed when the interrupt
  22          ;; hit.
  23          ((sb!pcl::*cache-miss-values-stack* nil)
  24           (sb!pcl::*dfun-miss-gfs-on-stack* nil)
  25           ;; Unless we do this, ADJUST-ARRAY and SORT would need to
  26           ;; disable interrupts.
  27           (,empty (vector))
  28           (sb!impl::*zap-array-data-temp* ,empty)
  29           (sb!impl::*merge-sort-temp-vector* ,empty))
  30        ,@body)))
  31
  32 (defun invoke-interruption (function)
  33   (without-interrupts
  34     (with-interrupt-bindings
  35       ;; Reset signal mask: the C-side handler has blocked all
  36       ;; deferrable interrupts before arranging return to lisp. This is
  37       ;; safe because we can't get a pending interrupt before we unblock
  38       ;; signals.
  39       ;;
  40       ;; FIXME: Should we not reset the _entire_ mask, but just
  41       ;; restore it to the state before we got the interrupt?
  42       (reset-signal-mask)
  43       (let ((sb!debug:*stack-top-hint* (nth-value 1 (sb!kernel:find-interrupted-name-and-frame))))
  44         (allow-with-interrupts (funcall function))))))
  45
  46 (defmacro in-interruption ((&key) &body body)
  47   #!+sb-doc
  48   "Convenience macro on top of INVOKE-INTERRUPTION."
  49   `(dx-flet ((interruption () ,@body))
  50      (invoke-interruption #'interruption)))
  51 \f
  52 ;;;; system calls that deal with signals
  53
  54 ;;; Send the signal SIGNAL to the process with process id PID. SIGNAL
  55 ;;; should be a valid signal number
  56 #!-sb-fluid (declaim (inline real-unix-kill))
  57 (sb!alien:define-alien-routine ("kill" unix-kill) sb!alien:int
  58   (pid sb!alien:int)
  59   (signal sb!alien:int))
  60
  61 ;;; Send the signal SIGNAL to the all the process in process group
  62 ;;; PGRP. SIGNAL should be a valid signal number
  63 #!-sb-fluid (declaim (inline real-unix-killpg))
  64 (sb!alien:define-alien-routine ("killpg" unix-killpg) sb!alien:int
  65   (pgrp sb!alien:int)
  66   (signal sb!alien:int))
  67
  68 ;;; Reset the current set of masked signals (those being blocked from
  69 ;;; delivery).
  70 ;;;
  71 ;;; (Note: CMU CL had a more general SIGSETMASK call and a SIGMASK
  72 ;;; operator to create masks, but since we only ever reset to 0, we no
  73 ;;; longer support it. If you need it, you can pull it out of the CMU
  74 ;;; CL sources, or the old SBCL sources; but you might also consider
  75 ;;; doing things the SBCL way and moving this kind of C-level work
  76 ;;; down to C wrapper functions.)
  77
  78 ;;; When inappropriate build options are used, this also prints messages
  79 ;;; listing the signals that were masked
  80 (sb!alien:define-alien-routine "reset_signal_mask" sb!alien:void)
  81
  82 \f
  83 ;;;; C routines that actually do all the work of establishing signal handlers
  84 (sb!alien:define-alien-routine ("install_handler" install-handler)
  85                                sb!alien:unsigned-long
  86   (signal sb!alien:int)
  87   (handler sb!alien:unsigned-long))
  88
  89 ;;;; interface to enabling and disabling signal handlers
  90
  91 (defun enable-interrupt (signal handler)
  92   (declare (type (or function fixnum (member :default :ignore)) handler))
  93   (/show0 "enable-interrupt")
  94   (flet ((run-handler (&rest args)
  95            (declare (truly-dynamic-extent args))
  96            (in-interruption ()
  97              (apply handler args))))
  98     (without-gcing
  99       (let ((result (install-handler signal
 100                                      (case handler
 101                                        (:default sig-dfl)
 102                                        (:ignore sig-ign)
 103                                        (t
 104                                         (sb!kernel:get-lisp-obj-address
 105                                          #'run-handler))))))
 106         (cond ((= result sig-dfl) :default)
 107               ((= result sig-ign) :ignore)
 108               (t (the (or function fixnum)
 109                    (sb!kernel:make-lisp-obj result))))))))
 110
 111 (defun default-interrupt (signal)
 112   (enable-interrupt signal :default))
 113
 114 (defun ignore-interrupt (signal)
 115   (enable-interrupt signal :ignore))
 116 \f
 117 ;;;; default LISP signal handlers
 118 ;;;;
 119 ;;;; Most of these just call ERROR to report the presence of the signal.
 120
 121 ;;; SIGINT is handled like BREAK, except that ANSI BREAK ignores
 122 ;;; *DEBUGGER-HOOK*, but we want SIGINT's BREAK to respect it, so that
 123 ;;; SIGINT in --disable-debugger mode will cleanly terminate the system
 124 ;;; (by respecting the *DEBUGGER-HOOK* established in that mode).
 125 (eval-when (:compile-toplevel :execute)
 126   (sb!xc:defmacro define-signal-handler (name what &optional (function 'error))
 127     `(defun ,name (signal info context)
 128        (declare (ignore signal info))
 129        (declare (type system-area-pointer context))
 130        (/show "in Lisp-level signal handler" ,(symbol-name name)
 131               (sap-int context))
 132        (with-interrupts
 133          (,function ,(concatenate 'simple-string what " at #X~X")
 134                     (with-alien ((context (* os-context-t) context))
 135                       (sap-int (sb!vm:context-pc context))))))))
 136
 137 (define-signal-handler sigill-handler "illegal instruction")
 138 #!-linux
 139 (define-signal-handler sigemt-handler "SIGEMT")
 140 (define-signal-handler sigbus-handler "bus error")
 141 (define-signal-handler sigsegv-handler "segmentation violation")
 142 #!-linux
 143 (define-signal-handler sigsys-handler "bad argument to a system call")
 144
 145 (defun sigint-handler (signal info context)
 146   (declare (ignore signal info))
 147   (declare (type system-area-pointer context))
 148   (/show "in Lisp-level SIGINT handler" (sap-int context))
 149   (flet ((interrupt-it ()
 150            (with-alien ((context (* os-context-t) context))
 151              (%break 'sigint 'interactive-interrupt
 152                      :context context
 153                      :address (sap-int (sb!vm:context-pc context))))))
 154     (sb!thread:interrupt-thread (sb!thread::foreground-thread)
 155                                 #'interrupt-it)))
 156
 157 (defun sigalrm-handler (signal info context)
 158   (declare (ignore signal info context))
 159   (declare (type system-area-pointer context))
 160   (sb!impl::run-expired-timers))
 161
 162 (defun sigterm-handler (signal code context)
 163   (declare (ignore signal code context))
 164   (sb!thread::terminate-session)
 165   (sb!ext:quit))
 166
 167 ;; Also known as SIGABRT.
 168 (defun sigiot-handler (signal code context)
 169   (declare (ignore signal code context))
 170   (sb!impl::%halt))
 171
 172 (defun sb!kernel:signal-cold-init-or-reinit ()
 173   #!+sb-doc
 174   "Enable all the default signals that Lisp knows how to deal with."
 175   (enable-interrupt sigint #'sigint-handler)
 176   (enable-interrupt sigterm #'sigterm-handler)
 177   (enable-interrupt sigill #'sigill-handler)
 178   (enable-interrupt sigiot #'sigiot-handler)
 179   #!-linux
 180   (enable-interrupt sigemt #'sigemt-handler)
 181   (enable-interrupt sigfpe #'sb!vm:sigfpe-handler)
 182   (enable-interrupt sigbus #'sigbus-handler)
 183   (enable-interrupt sigsegv #'sigsegv-handler)
 184   #!-linux
 185   (enable-interrupt sigsys #'sigsys-handler)
 186   (ignore-interrupt sigpipe)
 187   (enable-interrupt sigalrm #'sigalrm-handler)
 188   (sb!unix::reset-signal-mask)
 189   (values))
 190 \f
 191 ;;;; etc.
 192
 193 ;;; extract si_code from siginfo_t
 194 (sb!alien:define-alien-routine ("siginfo_code" siginfo-code) sb!alien:int
 195   (info system-area-pointer))
 196
 197 ;;; CMU CL comment:
 198 ;;;   Magically converted by the compiler into a break instruction.
 199 (defun receive-pending-interrupt ()
 200   (receive-pending-interrupt))