view release on metacpan or  search on metacpan

exercises/compile-tcsh/tcsh-6.10.00/sh.sem.c  view on Meta::CPAN

	else {			/* not a command */
	    bifunc = NULL;
	    if (noexec)
		break;
	}

	/*
	 * We fork only if we are timed, or are not the end of a parenthesized
	 * list and not a simple builtin function. Simple meaning one that is
	 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not
	 * fork in some of these cases.
	 */
	/*
	 * Prevent forking cd, pushd, popd, chdir cause this will cause the
	 * shell not to change dir!
	 */
#ifdef BACKPIPE
	/*
	 * Can't have NOFORK for the tail of a pipe - because it is not the
	 * last command spawned (even if it is at the end of a parenthesised
	 * list).
	 */
	if (t->t_dflg & F_PIPEIN)
	    t->t_dflg &= ~(F_NOFORK);
#endif /* BACKPIPE */
	if (bifunc && (bifunc->bfunct == (bfunc_t)dochngd ||
		       bifunc->bfunct == (bfunc_t)dopushd ||
		       bifunc->bfunct == (bfunc_t)dopopd))
	    t->t_dflg &= ~(F_NICE);
	if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 &&
	     (!bifunc || t->t_dflg &
	      (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP | F_HUP)))) ||
	/*
	 * We have to fork for eval too.
	 */
	    (bifunc && (t->t_dflg & F_PIPEIN) != 0 &&
	     bifunc->bfunct == (bfunc_t)doeval)) {
#ifdef VFORK
	    if (t->t_dtyp == NODE_PAREN ||
		t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc)
#endif /* VFORK */
	    {
		forked++;
		/*
		 * We need to block SIGCHLD here, so that if the process does
		 * not die before we can set the process group
		 */
		if (wanttty >= 0 && !nosigchld) {
#ifdef BSDSIGS
		    csigmask = sigblock(sigmask(SIGCHLD));
#else /* !BSDSIGS */
		    (void) sighold(SIGCHLD);
#endif /* BSDSIGS */

		    nosigchld = 1;
		}

		pid = pfork(t, wanttty);
		if (pid == 0 && nosigchld) {
#ifdef BSDSIGS
		    (void) sigsetmask(csigmask);
#else /* !BSDSIGS */
		    (void) sigrelse(SIGCHLD);
#endif /* BSDSIGS */
		    nosigchld = 0;
		}
		else if (pid != 0 && (t->t_dflg & F_AMPERSAND))
		    backpid = pid;
	    }

#ifdef VFORK
	    else {
		int     ochild, osetintr, ohaderr, odidfds;
		int     oSHIN, oSHOUT, oSHDIAG, oOLDSTD, otpgrp;
		int     oisoutatty, oisdiagatty;

# ifndef CLOSE_ON_EXEC
		int     odidcch;
# endif  /* !CLOSE_ON_EXEC */
# ifdef BSDSIGS
		sigmask_t omask, ocsigmask;
# endif /* BSDSIGS */

		/*
		 * Prepare for the vfork by saving everything that the child
		 * corrupts before it exec's. Note that in some signal
		 * implementations which keep the signal info in user space
		 * (e.g. Sun's) it will also be necessary to save and restore
		 * the current sigvec's for the signals the child touches
		 * before it exec's.
		 */

		/*
		 * Sooooo true... If this is a Sun, save the sigvec's. (Skip
		 * Gilbrech - 11/22/87)
		 */
# ifdef SAVESIGVEC
		sigvec_t savesv[NSIGSAVED];
		sigmask_t savesm;

# endif /* SAVESIGVEC */
		if (wanttty >= 0 && !nosigchld && !noexec) {
# ifdef BSDSIGS
		    csigmask = sigblock(sigmask(SIGCHLD));
# else /* !BSDSIGS */
		    (void) sighold(SIGCHLD);
# endif  /* BSDSIGS */
		    nosigchld = 1;
		}
# ifdef BSDSIGS
		omask = sigblock(sigmask(SIGCHLD)|sigmask(SIGINT));
# else /* !BSDSIGS */
		(void) sighold(SIGCHLD);
		(void) sighold(SIGINT);
# endif  /* BSDSIGS */
		ochild = child;
		osetintr = setintr;
		ohaderr = haderr;
		odidfds = didfds;
# ifndef CLOSE_ON_EXEC
		odidcch = didcch;
# endif /* !CLOSE_ON_EXEC */
		oSHIN = SHIN;
		oSHOUT = SHOUT;
		oSHDIAG = SHDIAG;
		oOLDSTD = OLDSTD;
		otpgrp = tpgrp;
		oisoutatty = isoutatty;
		oisdiagatty = isdiagatty;
# ifdef BSDSIGS
		ocsigmask = csigmask;
# endif /* BSDSIGS */
		onosigchld = nosigchld;
		Vsav = Vdp = 0;
		Vexpath = 0;
		Vt = 0;
# ifdef SAVESIGVEC
		savesm = savesigvec(savesv);
# endif /* SAVESIGVEC */
		if (use_fork)
		    pid = fork();
		else
		    pid = vfork();

		if (pid < 0) {
# ifdef BSDSIGS
#  ifdef SAVESIGVEC
		    restoresigvec(savesv, savesm);
#  endif /* SAVESIGVEC */
		    (void) sigsetmask(omask);
# else /* !BSDSIGS */
		    (void) sigrelse(SIGCHLD);
		    (void) sigrelse(SIGINT);
# endif  /* BSDSIGS */
		    stderror(ERR_NOPROC);
		}
		forked++;
		if (pid) {	/* parent */
# ifdef SAVESIGVEC
		    restoresigvec(savesv, savesm);
# endif /* SAVESIGVEC */
		    child = ochild;
		    setintr = osetintr;
		    haderr = ohaderr;
		    didfds = odidfds;
		    SHIN = oSHIN;
# ifndef CLOSE_ON_EXEC
		    didcch = odidcch;
# endif /* !CLOSE_ON_EXEC */
		    SHOUT = oSHOUT;
		    SHDIAG = oSHDIAG;
		    OLDSTD = oOLDSTD;
		    tpgrp = otpgrp;
		    isoutatty = oisoutatty;
		    isdiagatty = oisdiagatty;
# ifdef BSDSIGS
		    csigmask = ocsigmask;
# endif /* BSDSIGS */
		    nosigchld = onosigchld;

		    xfree((ptr_t) Vsav);
		    Vsav = 0;
		    xfree((ptr_t) Vdp);
		    Vdp = 0;
		    xfree((ptr_t) Vexpath);
		    Vexpath = 0;
		    blkfree((Char **) Vt);
		    Vt = 0;
		    /* this is from pfork() */
		    palloc(pid, t);
# ifdef BSDSIGS
		    (void) sigsetmask(omask);
# else /* !BSDSIGS */
		    (void) sigrelse(SIGCHLD);
		    (void) sigrelse(SIGINT);
# endif  /* BSDSIGS */
		}
		else {		/* child */
		    /* this is from pfork() */
		    int     pgrp;
		    bool    ignint = 0;
		    if (nosigchld) {
# ifdef BSDSIGS
			(void) sigsetmask(csigmask);
# else /* !BSDSIGS */
			(void) sigrelse(SIGCHLD);
# endif /* BSDSIGS */
			nosigchld = 0;
		    }

		    if (setintr)
			ignint = (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT))
				|| (gointr && eq(gointr, STRminus));
		    pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
		    child++;
		    if (setintr) {
			setintr = 0;
/*
 * casts made right for SunOS 4.0 by Douglas C. Schmidt
 * <schmidt%sunshine.ics.uci.edu@ROME.ICS.UCI.EDU>
 * (thanks! -- PWP)
 *
 * ignint ifs cleaned by Johan Widen <mcvax!osiris.sics.se!jw@uunet.UU.NET>
 * (thanks again)
 */
			if (ignint) {
			    (void) signal(SIGINT, SIG_IGN);
			    (void) signal(SIGQUIT, SIG_IGN);
			}
			else {
			    (void) signal(SIGINT,  vffree);
			    (void) signal(SIGQUIT, SIG_DFL);
			}
# ifdef BSDJOBS
			if (wanttty >= 0) {
			    (void) signal(SIGTSTP, SIG_DFL);
			    (void) signal(SIGTTIN, SIG_DFL);
			    (void) signal(SIGTTOU, SIG_DFL);
			}
# endif /* BSDJOBS */

			(void) signal(SIGTERM, parterm);
		    }
		    else if (tpgrp == -1 &&
			     (t->t_dflg & F_NOINTERRUPT)) {
			(void) signal(SIGINT, SIG_IGN);
			(void) signal(SIGQUIT, SIG_IGN);
		    }

		    pgetty(wanttty, pgrp);

		    if (t->t_dflg & F_NOHUP)
			(void) signal(SIGHUP, SIG_IGN);
		    if (t->t_dflg & F_HUP)
			(void) signal(SIGHUP, SIG_DFL);
		    if (t->t_dflg & F_NICE) {
			int nval = SIGN_EXTEND_CHAR(t->t_nice);
# ifdef BSDNICE
			(void) setpriority(PRIO_PROCESS, 0, nval);
# else /* !BSDNICE */
			(void) nice(nval);
# endif /* BSDNICE */
		    }
# ifdef F_VER
		    if (t->t_dflg & F_VER) {
			tsetenv(STRSYSTYPE, t->t_systype ? STRbsd43 : STRsys53);
			dohash(NULL, NULL);
		    }
# endif /* F_VER */
		}

	    }
#endif /* VFORK */
	}
	if (pid != 0) {
	    /*
	     * It would be better if we could wait for the whole job when we
	     * knew the last process had been started.  Pwait, in fact, does
	     * wait for the whole job anyway, but this test doesn't really
	     * express our intentions.
	     */
#ifdef BACKPIPE
	    if (didfds == 0 && t->t_dflg & F_PIPEOUT) {
		(void) close(pipeout[0]);
		(void) close(pipeout[1]);
	    }
	    if ((t->t_dflg & F_PIPEIN) != 0)
		break;
#else /* !BACKPIPE */
	    if (didfds == 0 && t->t_dflg & F_PIPEIN) {
		(void) close(pipein[0]);
		(void) close(pipein[1]);
	    }
	    if ((t->t_dflg & F_PIPEOUT) != 0)
		break;
#endif /* BACKPIPE */

	    if (nosigchld) {
#ifdef BSDSIGS
		(void) sigsetmask(csigmask);
#else /* !BSDSIGS */
		(void) sigrelse(SIGCHLD);
#endif /* BSDSIGS */
		nosigchld = 0;
	    }
	    if ((t->t_dflg & F_AMPERSAND) == 0)
		pwait();
	    break;
	}

	doio(t, pipein, pipeout);
#ifdef BACKPIPE
	if (t->t_dflg & F_PIPEIN) {
	    (void) close(pipein[0]);
	    (void) close(pipein[1]);
	}
#else /* !BACKPIPE */
	if (t->t_dflg & F_PIPEOUT) {
	    (void) close(pipeout[0]);
	    (void) close(pipeout[1]);
	}
#endif /* BACKPIPE */
	/*
	 * Perform a builtin function. If we are not forked, arrange for
	 * possible stopping
	 */
	if (bifunc) {
	    func(t, bifunc);
	    if (forked)
		exitstat();
	    break;
	}
	if (t->t_dtyp != NODE_PAREN) {
	    doexec(t);
	    /* NOTREACHED */
	}
	/*
	 * For () commands must put new 0,1,2 in FSH* and recurse
	 */
	OLDSTD = dcopy(0, FOLDSTD);
	SHOUT = dcopy(1, FSHOUT);
	isoutatty = isatty(SHOUT);
	SHDIAG = dcopy(2, FSHDIAG);
	isdiagatty = isatty(SHDIAG);
	(void) close(SHIN);
	SHIN = -1;
#ifndef CLOSE_ON_EXEC
	didcch = 0;
#endif /* !CLOSE_ON_EXEC */
	didfds = 0;
	wanttty = -1;
	t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT;
	execute(t->t_dspr, wanttty, NULL, NULL);
	exitstat();

    case NODE_PIPE:
#ifdef BACKPIPE
	t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
			(F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT));
	execute(t->t_dcdr, wanttty, pv, pipeout);