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Annotation of 42BSD/bin/csh/sh.sig.c, revision 1.1.1.1

1.1       root        1: static char *sccsid = "@(#)sh.sig.c    4.1 (Berkeley) 83/06/11";
                      2: 
                      3: /*
                      4:  * C shell - old jobs library sigrelse meant unblock mask
                      5:  *          AND reinstall handler, so we simulate it here.
                      6:  */
                      7: #include <signal.h>
                      8: 
                      9: #define        mask(s) (1 << ((s)-1))
                     10: 
                     11: static int (*actions[NSIG])();
                     12: static int achanged[NSIG];
                     13: 
                     14: /*
                     15:  * Perform action and save handler state.
                     16:  */
                     17: sigset(s, a)
                     18:        int s, (*a)();
                     19: {
                     20: 
                     21:        actions[s] = a;
                     22:        achanged[s] = 0;
                     23:        return ((int)signal(s, a));
                     24: }
                     25: 
                     26: /*
                     27:  * Release any masking of signal and
                     28:  * reinstall handler in case someone's
                     29:  * done a sigignore.
                     30:  */
                     31: sigrelse(s)
                     32:        int s;
                     33: {
                     34: 
                     35:        if (achanged[s]) {
                     36:                signal(s, actions[s]);
                     37:                achanged[s] = 0;
                     38:        }
                     39:        sigsetmask(sigblock(0) &~ mask(s));
                     40: }
                     41: 
                     42: /*
                     43:  * Ignore signal but maintain state so sigrelse
                     44:  * will restore handler.  We avoid the overhead
                     45:  * of doing a signal for each sigrelse call by
                     46:  * marking the signal's action as changed.
                     47:  */
                     48: sigignore(s)
                     49:        int s;
                     50: {
                     51: 
                     52:        if (actions[s] != SIG_IGN)
                     53:                achanged[s] = 1;
                     54:        signal(s, SIG_IGN);
                     55: }

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