macro and text revision (-mdoc version 3)

[unix-history] / usr / src / lib / libc / gen / signalsim.c

/*      signalsim.c     4.4     84/11/04        */

/*
* Almost backwards compatible signal.
*/
#include <signal.h>

enum {NATIVE = 0x0, UNKNOWN = 0x1, SIMULATE = 0x3} _sigsim = UNKNOWN;

int (*
signalsim(s, a))()
       int s, (*a)();
{
       struct sigvec osv, sv;
       int badcall();

       switch (_sigsim) {
       case UNKNOWN:
               sv.sv_handler = badcall;
               sv.sv_mask = sv.sv_onstack = 0;
               if (sigvec(SIGSYS, &sv, &osv) < 0) {
                       _sigsim = SIMULATE;
               } else {
                       _sigsim = NATIVE;
                       signal(SIGSYS, osv.sv_handler);
               }
               /* fall through */
       case NATIVE:
       case SIMULATE:
               sv.sv_handler = a;
               sv.sv_mask = sv.sv_onstack = 0;
               if (sigvec(s, &sv, &osv) < 0)
                       return (BADSIG);
               return (osv.sv_handler);
       }
}

/*
* Signal call will trap to here if not implemented
*/
badcall()
{
       _sigsim = SIMULATE;
}