1 ;;;; handling UNIX signals
3 ;;;; This software is part of the SBCL system. See the README file for
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.
12 (in-package "SB!UNIX")
17 ;;;; macros for dynamically enabling and disabling signal handling
19 ;;; Notes on how the without-interrupts/with-interrupts stuff works:
21 ;;; Before invoking the supplied handler for any of the signals that
22 ;;; can be blocked, the C interrupt support code checks to see whether
23 ;;; *interrupts-enabled* has been bound to NIL. If so, it saves the
24 ;;; signal number and the value of the signal mask (from the signal
25 ;;; context), sets the signal mask to block all blockable signals,
26 ;;; sets *interrupt-pending* and returns without handling the signal.
28 ;;; When we drop out the without interrupts, we check to see whether
29 ;;; *interrupt-pending* has been set. If so, we call
30 ;;; do-pending-interrupt, which generates a SIGTRAP. The C code
31 ;;; invokes the handler for the saved signal instead of the SIGTRAP
32 ;;; after replacing the signal mask in the signal context with the
33 ;;; saved value. When that hander returns, the original signal mask is
34 ;;; installed, allowing any other pending signals to be handled.
36 ;;; This means that the cost of without-interrupts is just a special
37 ;;; binding in the case when no signals are delivered (the normal
38 ;;; case). It's only when a signal is actually delivered that we use
39 ;;; any system calls, and by then the cost of the extra system calls
40 ;;; are lost in the noise when compared with the cost of delivering
41 ;;; the signal in the first place.
43 ;;; Magically converted by the compiler into a break instruction.
44 (defun do-pending-interrupt ()
45 (do-pending-interrupt))
49 (defvar *interrupts-enabled* t)
50 (defvar *interrupt-pending* nil)
52 (sb!xc:defmacro without-interrupts (&body body)
54 "Execute BODY in a context impervious to interrupts."
55 (let ((name (gensym)))
56 `(flet ((,name () ,@body))
57 (if *interrupts-enabled*
59 (let ((*interrupts-enabled* nil))
61 ;; FIXME: Does it matter that an interrupt coming in here
62 ;; could be executed before any of the pending interrupts?
63 ;; Or do incoming interrupts have the good grace to check
64 ;; whether interrupts are pending before executing themselves
66 (when *interrupt-pending*
67 (do-pending-interrupt)))
70 (sb!xc:defmacro with-interrupts (&body body)
72 "Allow interrupts while executing BODY. As interrupts are normally allowed,
73 this is only useful inside a WITHOUT-INTERRUPTS."
74 (let ((name (gensym)))
75 `(flet ((,name () ,@body))
76 (if *interrupts-enabled*
78 (let ((*interrupts-enabled* t))
79 (when *interrupt-pending*
80 (do-pending-interrupt))
85 ;;; On the GENGC system, we have to do it slightly differently because of the
86 ;;; existence of threads. Each thread has a suspends_disabled_count in its
87 ;;; mutator structure. When this value is other then zero, the low level stuff
88 ;;; will not suspend the thread, but will instead set the suspend_pending flag
89 ;;; (also in the mutator). So when we finish the without-interrupts, we just
90 ;;; check the suspend_pending flag and trigger a do-pending-interrupt if
94 (defmacro without-interrupts (&body body)
98 (declare (optimize (speed 3) (safety 0)))
99 (incf (sb!kernel:mutator-interrupts-disabled-count)))
102 (declare (optimize (speed 3) (safety 0)))
103 (when (and (zerop (decf (sb!kernel:mutator-interrupts-disabled-count)))
104 (not (zerop (sb!kernel:mutator-interrupt-pending))))
105 (do-pending-interrupt)))))
107 ;;;; utilities for dealing with signal names and numbers
109 (defstruct (unix-signal
110 (:constructor make-unix-signal (%name %number %description)))
111 %name ; signal keyword
112 (%number nil :type integer) ; UNIX signal number
113 (%description nil :type string)) ; documentation
115 (defvar *unix-signals* nil
117 "A list of Unix signal structures.")
119 (defmacro def-unix-signal (name number description)
120 (let ((symbol (intern (symbol-name name))))
122 ;; KLUDGE: This PUSH should be probably be something like PUSHNEW if we
123 ;; want to be able to cleanly reload this file. (Or perhaps
124 ;; *UNIX-SIGNALS* should be a hash table keyed by signal name, or a
125 ;; vector keyed by signal number?)
126 (push (make-unix-signal ,name ,number ,description) *unix-signals*)
127 ;; This is to make the new signal lookup stuff compatible with
128 ;; old code which expects the symbol with the same print name as
129 ;; our keywords to be a constant with a value equal to the signal
131 (defconstant ,symbol ,number ,description)
132 (let ((sb!int::*rogue-export* "DEF-MATH-RTN"))
133 (export ',symbol)))))
135 (defun unix-signal-or-lose (arg)
136 (let ((signal (find arg *unix-signals*
138 (symbol #'unix-signal-%name)
139 (number #'unix-signal-%number)))))
141 (error "~S is not a valid signal name or number." arg))
144 (defun unix-signal-name (signal)
146 "Return the name of the signal as a string. Signal should be a valid
147 signal number or a keyword of the standard UNIX signal name."
148 (symbol-name (unix-signal-%name (unix-signal-or-lose signal))))
150 (defun unix-signal-description (signal)
152 "Return a string describing signal. Signal should be a valid signal
153 number or a keyword of the standard UNIX signal name."
154 (unix-signal-%description (unix-signal-or-lose signal)))
156 (defun unix-signal-number (signal)
158 "Return the number of the given signal. Signal should be a valid
159 signal number or a keyword of the standard UNIX signal name."
160 (unix-signal-%number (unix-signal-or-lose signal)))
163 (def-unix-signal :CHECK 0 "Check")
165 (def-unix-signal :SIGHUP 1 "Hangup")
166 (def-unix-signal :SIGINT 2 "Interrupt")
167 (def-unix-signal :SIGQUIT 3 "Quit")
168 (def-unix-signal :SIGILL 4 "Illegal instruction")
169 (def-unix-signal :SIGTRAP 5 "Trace trap")
170 (def-unix-signal :SIGIOT 6 "Iot instruction")
172 (def-unix-signal :SIGEMT 7 "Emt instruction")
173 (def-unix-signal :SIGFPE 8 "Floating point exception")
174 (def-unix-signal :SIGKILL 9 "Kill")
175 (def-unix-signal :SIGBUS #!-linux 10 #!+linux 7 "Bus error")
176 (def-unix-signal :SIGSEGV 11 "Segmentation violation")
178 (def-unix-signal :SIGSYS 12 "Bad argument to system call")
179 (def-unix-signal :SIGPIPE 13 "Write on a pipe with no one to read it")
180 (def-unix-signal :SIGALRM 14 "Alarm clock")
181 (def-unix-signal :SIGTERM 15 "Software termination signal")
183 (def-unix-signal :SIGSTKFLT 16 "Stack fault on coprocessor")
184 (def-unix-signal :SIGURG #!+svr4 21 #!-(or hpux svr4 linux) 16 #!+hpux 29
185 #!+linux 23 "Urgent condition present on socket")
186 (def-unix-signal :SIGSTOP #!-(or hpux svr4 linux) 17 #!+hpux 24 #!+svr4 23
188 (def-unix-signal :SIGTSTP #!-(or hpux svr4 linux) 18 #!+hpux 25 #!+svr4 24
189 #!+linux 20 "Stop signal generated from keyboard")
190 (def-unix-signal :SIGCONT #!-(or hpux svr4 linux) 19 #!+hpux 26 #!+svr4 25
191 #!+linux 18 "Continue after stop")
192 (def-unix-signal :SIGCHLD #!-(or linux hpux) 20
193 #!+hpux 18 #!+linux 17 "Child status has changed")
194 (def-unix-signal :SIGTTIN #!-(or hpux svr4) 21 #!+hpux 27 #!+svr4 26
195 "Background read attempted from control terminal")
196 (def-unix-signal :SIGTTOU #!-(or hpux svr4) 22 #!+hpux 28 #!+svr4 27
197 "Background write attempted to control terminal")
198 (def-unix-signal :SIGIO #!-(or hpux irix linux) 23 #!+(or hpux irix) 22
200 "I/O is possible on a descriptor")
202 (def-unix-signal :SIGXCPU #!-svr4 24 #!+svr4 30 "Cpu time limit exceeded")
204 (def-unix-signal :SIGXFSZ #!-svr4 25 #!+svr4 31 "File size limit exceeded")
205 (def-unix-signal :SIGVTALRM #!-(or hpux svr4) 26 #!+hpux 20 #!+svr4 28
206 "Virtual time alarm")
207 (def-unix-signal :SIGPROF #!-(or hpux svr4 linux) 27 #!+hpux 21 #!+svr4 29
208 #!+linux 30 "Profiling timer alarm")
209 (def-unix-signal :SIGWINCH #!-(or hpux svr4) 28 #!+hpux 23 #!+svr4 20
210 "Window size change")
211 (def-unix-signal :SIGUSR1 #!-(or hpux svr4 linux) 30 #!+(or hpux svr4) 16
212 #!+linux 10 "User defined signal 1")
213 (def-unix-signal :SIGUSR2 #!-(or hpux svr4 linux) 31 #!+(or hpux svr4) 17
214 #!+linux 12 "User defined signal 2")
217 (def-unix-signal :SIGEMSG 30 "Mach Emergency message")
219 (def-unix-signal :SIGMSG 31 "Mach message")
221 ;;; SVR4 (or Solaris?) specific signals
223 (def-unix-signal :SIGWAITING 32 "Process's lwps are blocked")
225 (sb!xc:defmacro sigmask (&rest signals)
227 "Returns a mask given a set of signals."
229 (mapcar #'(lambda (signal)
230 (ash 1 (1- (unix-signal-number signal))))