120 lines
2.7 KiB
C
120 lines
2.7 KiB
C
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/*
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Dedicated treatment of the sigtrp system call, MON 48.
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*/
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/* $Header$ */
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#include <signal.h>
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#include "global.h"
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#include "log.h"
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#include "warn.h"
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#include "trap.h"
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/*************************** SIGTRP *************************************
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* The monitor call "sigtrp()" is handled by "do_sigtrp()". The first *
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* argument is a EM-trap number (0<=tn<=252), the second a UNIX signal *
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* number. The user wants trap "tn" to be generated, in case signal *
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* "sn" occurs. The report about this interpreter has a section, *
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* giving all details about signal handling. Do_sigtrp() returns the *
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* previous trap-number "sn" was mapped onto. A return value of -1 *
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* indicates an error. *
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************************************************************************/
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#define UNIX_trap(sn) (SIGILL <= sn && sn <= SIGSYS)
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PRIVATE int sig_map[NSIG+1]; /* maps signals onto trap numbers */
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PRIVATE int HndlIntSig(); /* handle signal to interpreter */
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PRIVATE int HndlEmSig(); /* handle signal to user program */
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init_signals() {
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int sn;
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for (sn = 0; sn < NSIG+1; sn++) {
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sig_map[sn] = -2; /* Default EM trap number */
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}
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for (sn = 0; sn < NSIG+1; sn++) {
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/* for all signals that would cause termination */
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if (!UNIX_trap(sn)) {
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if (signal(sn, SIG_IGN) != SIG_IGN) {
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/* we take our fate in our own hand */
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signal(sn, HndlIntSig);
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}
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}
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}
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}
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int do_sigtrp(tn, sn)
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int tn; /* EM trap number */
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int sn; /* UNIX signal number */
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{
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register int old_tn;
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if (sn <= 0 || sn > NSIG) {
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einval(WILLSN);
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return (-1);
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}
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if (UNIX_trap(sn)) {
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einval(WUNIXTR);
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return (-1);
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}
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old_tn = sig_map[sn];
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sig_map[sn] = tn;
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if (tn == -2) { /* reset default for signal sn */
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signal(sn, SIG_DFL);
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}
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else if (tn == -3) { /* ignore signal sn */
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signal(sn, SIG_IGN);
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}
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else if (tn >= 0 && tn <= 252) {/* legal tn */
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if ((int)signal(sn, HndlEmSig) == -1) {
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sig_map[sn] = old_tn;
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return (-1);
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}
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}
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else {
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/* illegal trap number */
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einval(WILLTN);
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sig_map[sn] = old_tn; /* restore sig_map */
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return (-1);
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}
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return (old_tn);
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}
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trap_signal()
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{
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/* execute the trap belonging to the signal that came in during
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the last instruction
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*/
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register int old_sig = signalled;
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signalled = 0;
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trap(sig_map[old_sig]);
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}
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/* The handling functions for the UNIX signals */
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PRIVATE HndlIntSig(sn)
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int sn;
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{
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/* The interpreter got the signal */
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signal(sn, SIG_IGN); /* peace and quiet for close_down() */
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LOG(("@t1 signal %d caught by interpreter", sn));
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message("interpreter received signal %d, which was not caught by the interpreted program",
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sn);
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close_down(1);
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}
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PRIVATE HndlEmSig(sn)
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int sn;
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{
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/* The EM machine got the signal */
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signal(sn, HndlIntSig); /* Revert to old situation */
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signalled = sn;
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}
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