BSD 4_1c_2 release

[unix-history] / usr / src / bin / sh / fault.c

/*      fault.c 4.1     82/05/07        */

#
/*
* UNIX shell
*
* S. R. Bourne
* Bell Telephone Laboratories
*
*/

#include        "defs.h"


STRING          trapcom[MAXTRAP];
BOOL            trapflg[MAXTRAP];

/* ========     fault handling routines    ======== */


VOID    fault(sig)
       REG INT         sig;
{
       REG INT         flag;

       signal(sig,fault);
       IF sig==MEMF
       THEN    IF setbrk(brkincr) == -1
               THEN    error(nospace);
               FI
       ELIF sig==ALARM
       THEN    IF flags&waiting
               THEN    done();
               FI
       ELSE    flag = (trapcom[sig] ? TRAPSET : SIGSET);
               trapnote |= flag;
               trapflg[sig] |= flag;
       FI
}

stdsigs()
{
       ignsig(QUIT);
       getsig(INTR);
       getsig(MEMF);
       getsig(ALARM);
}

ignsig(n)
{
       REG INT         s, i;

       IF (s=signal(i=n,1)&01)==0
       THEN    trapflg[i] |= SIGMOD;
       FI
       return(s);
}

getsig(n)
{
       REG INT         i;

       IF trapflg[i=n]&SIGMOD ORF ignsig(i)==0
       THEN    signal(i,fault);
       FI
}

oldsigs()
{
       REG INT         i;
       REG STRING      t;

       i=MAXTRAP;
       WHILE i--
       DO  t=trapcom[i];
           IF t==0 ORF *t
           THEN clrsig(i);
           FI
           trapflg[i]=0;
       OD
       trapnote=0;
}

clrsig(i)
       INT             i;
{
       free(trapcom[i]); trapcom[i]=0;
       IF trapflg[i]&SIGMOD
       THEN    signal(i,fault);
               trapflg[i] &= ~SIGMOD;
       FI
}

chktrap()
{
       /* check for traps */
       REG INT         i=MAXTRAP;
       REG STRING      t;

       trapnote &= ~TRAPSET;
       WHILE --i
       DO IF trapflg[i]&TRAPSET
          THEN trapflg[i] &= ~TRAPSET;
               IF t=trapcom[i]
               THEN    INT     savxit=exitval;
                       execexp(t,0);
                       exitval=savxit; exitset();
               FI
          FI
       OD
}