BSD 4_4_Lite1 development

[unix-history] / usr / src / contrib / rc-1.4 / signal.c

/* signal.c: a Hugh-approved signal handler. */

#include <signal.h>
#include <setjmp.h>
#include "rc.h"
#include "sigmsgs.h"
#include "jbwrap.h"

Jbwrap slowbuf;
volatile SIG_ATOMIC_T slow, interrupt_happened;
void (*sighandlers[NUMOFSIGNALS])(int);

static volatile SIG_ATOMIC_T sigcount, caught[NUMOFSIGNALS];

extern void catcher(int s) {
       if (forked)
               exit(1); /* exit unconditionally on a signal in a child process */
       if (caught[s] == 0) {
               sigcount++;
               caught[s] = 1;
       }
       signal(s, catcher);
       interrupt_happened = TRUE;
       if (slow)
               longjmp(slowbuf.j, 1);
}

extern void sigchk() {
       void (*h)(int);
       int s, i;
       if (sigcount == 0)
               return; /* ho hum; life as usual */
       if (forked)
               exit(1); /* exit unconditionally on a signal in a child process */
       for (i = 0, s = -1; i < NUMOFSIGNALS; i++)
               if (caught[i] != 0) {
                       s = i;
                       --sigcount;
                       caught[s] = 0;
                       break;
               }
       if (s == -1)
               panic("all-zero sig vector with nonzero sigcount");
       if ((h = sighandlers[s]) == SIG_DFL)
               panic("caught signal set to SIG_DFL");
       if (h == SIG_IGN)
               panic("caught signal set to SIG_IGN");
       (*h)(s);
}

extern void (*rc_signal(int s, void (*h)(int)))(int) {
       void (*old)(int);
       SIGCHK;
       old = sighandlers[s];
       if (h == SIG_DFL || h == SIG_IGN) {
               signal(s, h);
               sighandlers[s] = h;
       } else {
               sighandlers[s] = h;
               signal(s, catcher);
       }
       return old;
}

extern void initsignal() {
       void (*h)(int);
       int i;
       for (i = 1; i < NUMOFSIGNALS; i++) {
               if ((h = signal(i, SIG_DFL)) != SIG_DFL)
                       signal(i, h);
               sighandlers[i] = h;
       }
}