98 lines
2.9 KiB
C
98 lines
2.9 KiB
C
/* Need to define sig2interrupt vector.
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** Interrupt-system mutators should probably hold interrupts while they
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** operate.
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*/
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#include <unistd.h>
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#include <sys/types.h>
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#include <signal.h>
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#include <stdio.h>
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#include "cstuff.h"
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/* Make sure our exports match up w/the implementation: */
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#include "sighandlers1.h"
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/* Import the OS-dependent set of signals and their translations
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** to S48 vm interrupts.
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*/
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#include "signals1.h"
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extern int errno;
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/* Translate Unix signal numbers to S48 interrupt numbers. */
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s48_value sig2interrupt(s48_value _signal)
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{
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int signal = s48_extract_fixnum (_signal);
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return s48_enter_fixnum (( signal < 0 || signal > max_sig ) ? -1 :
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sig2int[signal]);
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}
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/* This guy is responsible for making the default action for a
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** Unix signal happen. Because S48's signal handler system is
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** interposed between delivery-to-the-process and
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** delivery-to-the-scheme-handler, when the user sets a signal
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** handler to default, we install a Scheme proc that calls this
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** guy, instead of just slapping a SIGDFL in as the Unix handler.
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** We only have to do this for signals whose default isn't "ignore," i.e.:
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** Posix: SIGALRM SIGHUP SIGINT SIGQUIT SIGTERM SIGUSR1 SIGUSR2
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** Non-Posix: SIGINFO SIGPOLL SIGPROF SIGVTALRM SIGXCPU SIGXFSZ SIGIO
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** This way, the S48 signal-blocking mechanism can work.
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**
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** Weird, I know.
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*/
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s48_value do_default_sigaction(s48_value _signal)
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{
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sigset_t ss, old_ss;
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struct sigaction default_action, old_action;
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int signal = s48_extract_fixnum(_signal);
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/* fprintf(stderr, "Doing default for signal %d\n", signal); */
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sigfillset(&ss); /* Block everyone. */
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sigprocmask(SIG_SETMASK, &ss, &old_ss);
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default_action.sa_handler = SIG_DFL; /* Set for default. */
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sigemptyset(&default_action.sa_mask);
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default_action.sa_flags = 0;
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sigaction(signal, &default_action, &old_action);
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raise(signal); /* Raise the signal. */
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sigdelset(&ss, signal);
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sigprocmask(SIG_SETMASK, &ss, 0); /* Handle it. */
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/* Most likely, we'll never get to here, as the default for
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** the signals we're handling is "terminate," but we'll play it safe.
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*/
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sigaction(signal, &old_action, 0); /* Restore old handler, */
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sigprocmask(SIG_SETMASK, &old_ss, 0); /* and mask. */
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return S48_UNSPECIFIC;
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}
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s48_value ignore_signal(s48_value _signal)
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{
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sig_t res = signal(s48_extract_fixnum(_signal), SIG_IGN);
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if (res == SIG_ERR)
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s48_raise_os_error_1(errno, _signal);
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return S48_UNSPECIFIC;
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}
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s48_value handle_signal_default(s48_value _signal)
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{
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sig_t res = signal(s48_extract_fixnum(_signal), SIG_DFL);
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if (res == SIG_ERR)
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s48_raise_os_error_1(errno, _signal);
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return S48_UNSPECIFIC;
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}
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s48_value s48_init_sighandlers(void)
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{
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S48_EXPORT_FUNCTION(sig2interrupt);
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S48_EXPORT_FUNCTION(do_default_sigaction);
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S48_EXPORT_FUNCTION(ignore_signal);
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S48_EXPORT_FUNCTION(handle_signal_default);
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return S48_UNSPECIFIC;
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}
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