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proc.c revision 1.6
      1 /*	$NetBSD: proc.c,v 1.6 1995/03/21 09:03:16 cgd Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1980, 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #ifndef lint
     37 #if 0
     38 static char sccsid[] = "@(#)proc.c	8.1 (Berkeley) 5/31/93";
     39 #else
     40 static char rcsid[] = "$NetBSD: proc.c,v 1.6 1995/03/21 09:03:16 cgd Exp $";
     41 #endif
     42 #endif /* not lint */
     43 
     44 #include <sys/types.h>
     45 #include <sys/wait.h>
     46 #include <errno.h>
     47 #include <unistd.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 #if __STDC__
     51 # include <stdarg.h>
     52 #else
     53 # include <varargs.h>
     54 #endif
     55 
     56 #include "csh.h"
     57 #include "dir.h"
     58 #include "proc.h"
     59 #include "extern.h"
     60 
     61 #define BIGINDEX	9	/* largest desirable job index */
     62 
     63 static struct rusage zru;
     64 
     65 static void	 pflushall __P((void));
     66 static void	 pflush __P((struct process *));
     67 static void	 pclrcurr __P((struct process *));
     68 static void	 padd __P((struct command *));
     69 static int	 pprint __P((struct process *, int));
     70 static void	 ptprint __P((struct process *));
     71 static void	 pads __P((Char *));
     72 static void	 pkill __P((Char **v, int));
     73 static struct	process
     74 		*pgetcurr __P((struct process *));
     75 static void	 okpcntl __P((void));
     76 
     77 /*
     78  * pchild - called at interrupt level by the SIGCHLD signal
     79  *	indicating that at least one child has terminated or stopped
     80  *	thus at least one wait system call will definitely return a
     81  *	childs status.  Top level routines (like pwait) must be sure
     82  *	to mask interrupts when playing with the proclist data structures!
     83  */
     84 /* ARGUSED */
     85 void
     86 pchild(notused)
     87 	int notused;
     88 {
     89     register struct process *pp;
     90     register struct process *fp;
     91     register int pid;
     92     extern int insource;
     93     union wait w;
     94     int     jobflags;
     95     struct rusage ru;
     96 
     97 loop:
     98     errno = 0;			/* reset, just in case */
     99     pid = wait3(&w.w_status,
    100        (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG), &ru);
    101 
    102     if (pid <= 0) {
    103 	if (errno == EINTR) {
    104 	    errno = 0;
    105 	    goto loop;
    106 	}
    107 	pnoprocesses = pid == -1;
    108 	return;
    109     }
    110     for (pp = proclist.p_next; pp != NULL; pp = pp->p_next)
    111 	if (pid == pp->p_pid)
    112 	    goto found;
    113     goto loop;
    114 found:
    115     if (pid == atoi(short2str(value(STRchild))))
    116 	unsetv(STRchild);
    117     pp->p_flags &= ~(PRUNNING | PSTOPPED | PREPORTED);
    118     if (WIFSTOPPED(w)) {
    119 	pp->p_flags |= PSTOPPED;
    120 	pp->p_reason = w.w_stopsig;
    121     }
    122     else {
    123 	if (pp->p_flags & (PTIME | PPTIME) || adrof(STRtime))
    124 	    (void) gettimeofday(&pp->p_etime, NULL);
    125 
    126 	pp->p_rusage = ru;
    127 	if (WIFSIGNALED(w)) {
    128 	    if (w.w_termsig == SIGINT)
    129 		pp->p_flags |= PINTERRUPTED;
    130 	    else
    131 		pp->p_flags |= PSIGNALED;
    132 	    if (w.w_coredump)
    133 		pp->p_flags |= PDUMPED;
    134 	    pp->p_reason = w.w_termsig;
    135 	}
    136 	else {
    137 	    pp->p_reason = w.w_retcode;
    138 	    if (pp->p_reason != 0)
    139 		pp->p_flags |= PAEXITED;
    140 	    else
    141 		pp->p_flags |= PNEXITED;
    142 	}
    143     }
    144     jobflags = 0;
    145     fp = pp;
    146     do {
    147 	if ((fp->p_flags & (PPTIME | PRUNNING | PSTOPPED)) == 0 &&
    148 	    !child && adrof(STRtime) &&
    149 	    fp->p_rusage.ru_utime.tv_sec + fp->p_rusage.ru_stime.tv_sec
    150 	    >= atoi(short2str(value(STRtime))))
    151 	    fp->p_flags |= PTIME;
    152 	jobflags |= fp->p_flags;
    153     } while ((fp = fp->p_friends) != pp);
    154     pp->p_flags &= ~PFOREGND;
    155     if (pp == pp->p_friends && (pp->p_flags & PPTIME)) {
    156 	pp->p_flags &= ~PPTIME;
    157 	pp->p_flags |= PTIME;
    158     }
    159     if ((jobflags & (PRUNNING | PREPORTED)) == 0) {
    160 	fp = pp;
    161 	do {
    162 	    if (fp->p_flags & PSTOPPED)
    163 		fp->p_flags |= PREPORTED;
    164 	} while ((fp = fp->p_friends) != pp);
    165 	while (fp->p_pid != fp->p_jobid)
    166 	    fp = fp->p_friends;
    167 	if (jobflags & PSTOPPED) {
    168 	    if (pcurrent && pcurrent != fp)
    169 		pprevious = pcurrent;
    170 	    pcurrent = fp;
    171 	}
    172 	else
    173 	    pclrcurr(fp);
    174 	if (jobflags & PFOREGND) {
    175 	    if (jobflags & (PSIGNALED | PSTOPPED | PPTIME) ||
    176 #ifdef IIASA
    177 		jobflags & PAEXITED ||
    178 #endif
    179 		!eq(dcwd->di_name, fp->p_cwd->di_name)) {
    180 		;		/* print in pjwait */
    181 	    }
    182 	    /* PWP: print a newline after ^C */
    183 	    else if (jobflags & PINTERRUPTED) {
    184 		(void) vis_fputc('\r' | QUOTE, cshout);
    185 		(void) fputc('\n', cshout);
    186 	    }
    187 	}
    188 	else {
    189 	    if (jobflags & PNOTIFY || adrof(STRnotify)) {
    190 		(void) vis_fputc('\r' | QUOTE, cshout);
    191 		(void) fputc('\n', cshout);
    192 		(void) pprint(pp, NUMBER | NAME | REASON);
    193 		if ((jobflags & PSTOPPED) == 0)
    194 		    pflush(pp);
    195 	    }
    196 	    else {
    197 		fp->p_flags |= PNEEDNOTE;
    198 		neednote++;
    199 	    }
    200 	}
    201     }
    202     goto loop;
    203 }
    204 
    205 void
    206 pnote()
    207 {
    208     register struct process *pp;
    209     int     flags;
    210     sigset_t omask;
    211 
    212     neednote = 0;
    213     for (pp = proclist.p_next; pp != NULL; pp = pp->p_next) {
    214 	if (pp->p_flags & PNEEDNOTE) {
    215 	    omask = sigblock(sigmask(SIGCHLD));
    216 	    pp->p_flags &= ~PNEEDNOTE;
    217 	    flags = pprint(pp, NUMBER | NAME | REASON);
    218 	    if ((flags & (PRUNNING | PSTOPPED)) == 0)
    219 		pflush(pp);
    220 	    (void) sigsetmask(omask);
    221 	}
    222     }
    223 }
    224 
    225 /*
    226  * pwait - wait for current job to terminate, maintaining integrity
    227  *	of current and previous job indicators.
    228  */
    229 void
    230 pwait()
    231 {
    232     register struct process *fp, *pp;
    233     sigset_t omask;
    234 
    235     /*
    236      * Here's where dead procs get flushed.
    237      */
    238     omask = sigblock(sigmask(SIGCHLD));
    239     for (pp = (fp = &proclist)->p_next; pp != NULL; pp = (fp = pp)->p_next)
    240 	if (pp->p_pid == 0) {
    241 	    fp->p_next = pp->p_next;
    242 	    xfree((ptr_t) pp->p_command);
    243 	    if (pp->p_cwd && --pp->p_cwd->di_count == 0)
    244 		if (pp->p_cwd->di_next == 0)
    245 		    dfree(pp->p_cwd);
    246 	    xfree((ptr_t) pp);
    247 	    pp = fp;
    248 	}
    249     (void) sigsetmask(omask);
    250     pjwait(pcurrjob);
    251 }
    252 
    253 
    254 /*
    255  * pjwait - wait for a job to finish or become stopped
    256  *	It is assumed to be in the foreground state (PFOREGND)
    257  */
    258 void
    259 pjwait(pp)
    260     register struct process *pp;
    261 {
    262     register struct process *fp;
    263     int     jobflags, reason;
    264     sigset_t omask;
    265 
    266     while (pp->p_pid != pp->p_jobid)
    267 	pp = pp->p_friends;
    268     fp = pp;
    269 
    270     do {
    271 	if ((fp->p_flags & (PFOREGND | PRUNNING)) == PRUNNING)
    272 	    (void) fprintf(csherr, "BUG: waiting for background job!\n");
    273     } while ((fp = fp->p_friends) != pp);
    274     /*
    275      * Now keep pausing as long as we are not interrupted (SIGINT), and the
    276      * target process, or any of its friends, are running
    277      */
    278     fp = pp;
    279     omask = sigblock(sigmask(SIGCHLD));
    280     for (;;) {
    281 	(void) sigblock(sigmask(SIGCHLD));
    282 	jobflags = 0;
    283 	do
    284 	    jobflags |= fp->p_flags;
    285 	while ((fp = (fp->p_friends)) != pp);
    286 	if ((jobflags & PRUNNING) == 0)
    287 	    break;
    288 #ifdef JOBDEBUG
    289 	(void) fprintf(csherr, "starting to sigpause for  SIGCHLD on %d\n",
    290 		       fp->p_pid);
    291 #endif				/* JOBDEBUG */
    292 	(void) sigpause(omask & ~sigmask(SIGCHLD));
    293     }
    294     (void) sigsetmask(omask);
    295     if (tpgrp > 0)		/* get tty back */
    296 	(void) tcsetpgrp(FSHTTY, tpgrp);
    297     if ((jobflags & (PSIGNALED | PSTOPPED | PTIME)) ||
    298 	!eq(dcwd->di_name, fp->p_cwd->di_name)) {
    299 	if (jobflags & PSTOPPED) {
    300 	    (void) fputc('\n', cshout);
    301 	    if (adrof(STRlistjobs)) {
    302 		Char   *jobcommand[3];
    303 
    304 		jobcommand[0] = STRjobs;
    305 		if (eq(value(STRlistjobs), STRlong))
    306 		    jobcommand[1] = STRml;
    307 		else
    308 		    jobcommand[1] = NULL;
    309 		jobcommand[2] = NULL;
    310 
    311 		dojobs(jobcommand, NULL);
    312 		(void) pprint(pp, SHELLDIR);
    313 	    }
    314 	    else
    315 		(void) pprint(pp, AREASON | SHELLDIR);
    316 	}
    317 	else
    318 	    (void) pprint(pp, AREASON | SHELLDIR);
    319     }
    320     if ((jobflags & (PINTERRUPTED | PSTOPPED)) && setintr &&
    321 	(!gointr || !eq(gointr, STRminus))) {
    322 	if ((jobflags & PSTOPPED) == 0)
    323 	    pflush(pp);
    324 	pintr1(0);
    325 	/* NOTREACHED */
    326     }
    327     reason = 0;
    328     fp = pp;
    329     do {
    330 	if (fp->p_reason)
    331 	    reason = fp->p_flags & (PSIGNALED | PINTERRUPTED) ?
    332 		fp->p_reason | META : fp->p_reason;
    333     } while ((fp = fp->p_friends) != pp);
    334     if ((reason != 0) && (adrof(STRprintexitvalue))) {
    335 	(void) fprintf(cshout, "Exit %d\n", reason);
    336     }
    337     set(STRstatus, putn(reason));
    338     if (reason && exiterr)
    339 	exitstat();
    340     pflush(pp);
    341 }
    342 
    343 /*
    344  * dowait - wait for all processes to finish
    345  */
    346 void
    347 /*ARGSUSED*/
    348 dowait(v, t)
    349     Char **v;
    350     struct command *t;
    351 {
    352     register struct process *pp;
    353     sigset_t omask;
    354 
    355     pjobs++;
    356     omask = sigblock(sigmask(SIGCHLD));
    357 loop:
    358     for (pp = proclist.p_next; pp; pp = pp->p_next)
    359 	if (pp->p_pid &&	/* pp->p_pid == pp->p_jobid && */
    360 	    pp->p_flags & PRUNNING) {
    361 	    (void) sigpause((sigset_t) 0);
    362 	    goto loop;
    363 	}
    364     (void) sigsetmask(omask);
    365     pjobs = 0;
    366 }
    367 
    368 /*
    369  * pflushall - flush all jobs from list (e.g. at fork())
    370  */
    371 static void
    372 pflushall()
    373 {
    374     register struct process *pp;
    375 
    376     for (pp = proclist.p_next; pp != NULL; pp = pp->p_next)
    377 	if (pp->p_pid)
    378 	    pflush(pp);
    379 }
    380 
    381 /*
    382  * pflush - flag all process structures in the same job as the
    383  *	the argument process for deletion.  The actual free of the
    384  *	space is not done here since pflush is called at interrupt level.
    385  */
    386 static void
    387 pflush(pp)
    388     register struct process *pp;
    389 {
    390     register struct process *np;
    391     register int idx;
    392 
    393     if (pp->p_pid == 0) {
    394 	(void) fprintf(csherr, "BUG: process flushed twice");
    395 	return;
    396     }
    397     while (pp->p_pid != pp->p_jobid)
    398 	pp = pp->p_friends;
    399     pclrcurr(pp);
    400     if (pp == pcurrjob)
    401 	pcurrjob = 0;
    402     idx = pp->p_index;
    403     np = pp;
    404     do {
    405 	np->p_index = np->p_pid = 0;
    406 	np->p_flags &= ~PNEEDNOTE;
    407     } while ((np = np->p_friends) != pp);
    408     if (idx == pmaxindex) {
    409 	for (np = proclist.p_next, idx = 0; np; np = np->p_next)
    410 	    if (np->p_index > idx)
    411 		idx = np->p_index;
    412 	pmaxindex = idx;
    413     }
    414 }
    415 
    416 /*
    417  * pclrcurr - make sure the given job is not the current or previous job;
    418  *	pp MUST be the job leader
    419  */
    420 static void
    421 pclrcurr(pp)
    422     register struct process *pp;
    423 {
    424 
    425     if (pp == pcurrent)
    426 	if (pprevious != NULL) {
    427 	    pcurrent = pprevious;
    428 	    pprevious = pgetcurr(pp);
    429 	}
    430 	else {
    431 	    pcurrent = pgetcurr(pp);
    432 	    pprevious = pgetcurr(pp);
    433 	}
    434     else if (pp == pprevious)
    435 	pprevious = pgetcurr(pp);
    436 }
    437 
    438 /* +4 here is 1 for '\0', 1 ea for << >& >> */
    439 static Char command[PMAXLEN + 4];
    440 static int cmdlen;
    441 static Char *cmdp;
    442 
    443 /*
    444  * palloc - allocate a process structure and fill it up.
    445  *	an important assumption is made that the process is running.
    446  */
    447 void
    448 palloc(pid, t)
    449     int     pid;
    450     register struct command *t;
    451 {
    452     register struct process *pp;
    453     int     i;
    454 
    455     pp = (struct process *) xcalloc(1, (size_t) sizeof(struct process));
    456     pp->p_pid = pid;
    457     pp->p_flags = t->t_dflg & F_AMPERSAND ? PRUNNING : PRUNNING | PFOREGND;
    458     if (t->t_dflg & F_TIME)
    459 	pp->p_flags |= PPTIME;
    460     cmdp = command;
    461     cmdlen = 0;
    462     padd(t);
    463     *cmdp++ = 0;
    464     if (t->t_dflg & F_PIPEOUT) {
    465 	pp->p_flags |= PPOU;
    466 	if (t->t_dflg & F_STDERR)
    467 	    pp->p_flags |= PERR;
    468     }
    469     pp->p_command = Strsave(command);
    470     if (pcurrjob) {
    471 	struct process *fp;
    472 
    473 	/* careful here with interrupt level */
    474 	pp->p_cwd = 0;
    475 	pp->p_index = pcurrjob->p_index;
    476 	pp->p_friends = pcurrjob;
    477 	pp->p_jobid = pcurrjob->p_pid;
    478 	for (fp = pcurrjob; fp->p_friends != pcurrjob; fp = fp->p_friends)
    479 	    continue;
    480 	fp->p_friends = pp;
    481     }
    482     else {
    483 	pcurrjob = pp;
    484 	pp->p_jobid = pid;
    485 	pp->p_friends = pp;
    486 	pp->p_cwd = dcwd;
    487 	dcwd->di_count++;
    488 	if (pmaxindex < BIGINDEX)
    489 	    pp->p_index = ++pmaxindex;
    490 	else {
    491 	    struct process *np;
    492 
    493 	    for (i = 1;; i++) {
    494 		for (np = proclist.p_next; np; np = np->p_next)
    495 		    if (np->p_index == i)
    496 			goto tryagain;
    497 		pp->p_index = i;
    498 		if (i > pmaxindex)
    499 		    pmaxindex = i;
    500 		break;
    501 	tryagain:;
    502 	    }
    503 	}
    504 	if (pcurrent == NULL)
    505 	    pcurrent = pp;
    506 	else if (pprevious == NULL)
    507 	    pprevious = pp;
    508     }
    509     pp->p_next = proclist.p_next;
    510     proclist.p_next = pp;
    511     (void) gettimeofday(&pp->p_btime, NULL);
    512 }
    513 
    514 static void
    515 padd(t)
    516     register struct command *t;
    517 {
    518     Char  **argp;
    519 
    520     if (t == 0)
    521 	return;
    522     switch (t->t_dtyp) {
    523 
    524     case NODE_PAREN:
    525 	pads(STRLparensp);
    526 	padd(t->t_dspr);
    527 	pads(STRspRparen);
    528 	break;
    529 
    530     case NODE_COMMAND:
    531 	for (argp = t->t_dcom; *argp; argp++) {
    532 	    pads(*argp);
    533 	    if (argp[1])
    534 		pads(STRspace);
    535 	}
    536 	break;
    537 
    538     case NODE_OR:
    539     case NODE_AND:
    540     case NODE_PIPE:
    541     case NODE_LIST:
    542 	padd(t->t_dcar);
    543 	switch (t->t_dtyp) {
    544 	case NODE_OR:
    545 	    pads(STRspor2sp);
    546 	    break;
    547 	case NODE_AND:
    548 	    pads(STRspand2sp);
    549 	    break;
    550 	case NODE_PIPE:
    551 	    pads(STRsporsp);
    552 	    break;
    553 	case NODE_LIST:
    554 	    pads(STRsemisp);
    555 	    break;
    556 	}
    557 	padd(t->t_dcdr);
    558 	return;
    559     }
    560     if ((t->t_dflg & F_PIPEIN) == 0 && t->t_dlef) {
    561 	pads((t->t_dflg & F_READ) ? STRspLarrow2sp : STRspLarrowsp);
    562 	pads(t->t_dlef);
    563     }
    564     if ((t->t_dflg & F_PIPEOUT) == 0 && t->t_drit) {
    565 	pads((t->t_dflg & F_APPEND) ? STRspRarrow2 : STRspRarrow);
    566 	if (t->t_dflg & F_STDERR)
    567 	    pads(STRand);
    568 	pads(STRspace);
    569 	pads(t->t_drit);
    570     }
    571 }
    572 
    573 static void
    574 pads(cp)
    575     Char   *cp;
    576 {
    577     register int i;
    578 
    579     /*
    580      * Avoid the Quoted Space alias hack! Reported by:
    581      * sam (at) john-bigboote.ICS.UCI.EDU (Sam Horrocks)
    582      */
    583     if (cp[0] == STRQNULL[0])
    584 	cp++;
    585 
    586     i = Strlen(cp);
    587 
    588     if (cmdlen >= PMAXLEN)
    589 	return;
    590     if (cmdlen + i >= PMAXLEN) {
    591 	(void) Strcpy(cmdp, STRsp3dots);
    592 	cmdlen = PMAXLEN;
    593 	cmdp += 4;
    594 	return;
    595     }
    596     (void) Strcpy(cmdp, cp);
    597     cmdp += i;
    598     cmdlen += i;
    599 }
    600 
    601 /*
    602  * psavejob - temporarily save the current job on a one level stack
    603  *	so another job can be created.  Used for { } in exp6
    604  *	and `` in globbing.
    605  */
    606 void
    607 psavejob()
    608 {
    609 
    610     pholdjob = pcurrjob;
    611     pcurrjob = NULL;
    612 }
    613 
    614 /*
    615  * prestjob - opposite of psavejob.  This may be missed if we are interrupted
    616  *	somewhere, but pendjob cleans up anyway.
    617  */
    618 void
    619 prestjob()
    620 {
    621 
    622     pcurrjob = pholdjob;
    623     pholdjob = NULL;
    624 }
    625 
    626 /*
    627  * pendjob - indicate that a job (set of commands) has been completed
    628  *	or is about to begin.
    629  */
    630 void
    631 pendjob()
    632 {
    633     register struct process *pp, *tp;
    634 
    635     if (pcurrjob && (pcurrjob->p_flags & (PFOREGND | PSTOPPED)) == 0) {
    636 	pp = pcurrjob;
    637 	while (pp->p_pid != pp->p_jobid)
    638 	    pp = pp->p_friends;
    639 	(void) fprintf(cshout, "[%d]", pp->p_index);
    640 	tp = pp;
    641 	do {
    642 	    (void) fprintf(cshout, " %d", pp->p_pid);
    643 	    pp = pp->p_friends;
    644 	} while (pp != tp);
    645 	(void) fputc('\n', cshout);
    646     }
    647     pholdjob = pcurrjob = 0;
    648 }
    649 
    650 /*
    651  * pprint - print a job
    652  */
    653 static int
    654 pprint(pp, flag)
    655     register struct process *pp;
    656     bool    flag;
    657 {
    658     register status, reason;
    659     struct process *tp;
    660     int     jobflags, pstatus;
    661     bool hadnl = 1;	/* did we just have a newline */
    662     char   *format;
    663 
    664     (void) fpurge(cshout);
    665 
    666     while (pp->p_pid != pp->p_jobid)
    667 	pp = pp->p_friends;
    668     if (pp == pp->p_friends && (pp->p_flags & PPTIME)) {
    669 	pp->p_flags &= ~PPTIME;
    670 	pp->p_flags |= PTIME;
    671     }
    672     tp = pp;
    673     status = reason = -1;
    674     jobflags = 0;
    675     do {
    676 	jobflags |= pp->p_flags;
    677 	pstatus = pp->p_flags & PALLSTATES;
    678 	if (tp != pp && !hadnl && !(flag & FANCY) &&
    679 	    ((pstatus == status && pp->p_reason == reason) ||
    680 	     !(flag & REASON))) {
    681 	    (void) fputc(' ', cshout);
    682 	    hadnl = 0;
    683 	}
    684 	else {
    685 	    if (tp != pp && !hadnl) {
    686 		(void) fputc('\n', cshout);
    687 		hadnl = 1;
    688 	    }
    689 	    if (flag & NUMBER) {
    690 		if (pp == tp)
    691 		    (void) fprintf(cshout, "[%d]%s %c ", pp->p_index,
    692 			    pp->p_index < 10 ? " " : "",
    693 			    pp == pcurrent ? '+' :
    694 			    (pp == pprevious ? '-' : ' '));
    695 		else
    696 		    (void) fprintf(cshout, "       ");
    697 		hadnl = 0;
    698 	    }
    699 	    if (flag & FANCY) {
    700 		(void) fprintf(cshout, "%5d ", pp->p_pid);
    701 		hadnl = 0;
    702 	    }
    703 	    if (flag & (REASON | AREASON)) {
    704 		if (flag & NAME)
    705 		    format = "%-23s";
    706 		else
    707 		    format = "%s";
    708 		if (pstatus == status)
    709 		    if (pp->p_reason == reason) {
    710 			(void) fprintf(cshout, format, "");
    711 			hadnl = 0;
    712 			goto prcomd;
    713 		    }
    714 		    else
    715 			reason = pp->p_reason;
    716 		else {
    717 		    status = pstatus;
    718 		    reason = pp->p_reason;
    719 		}
    720 		switch (status) {
    721 
    722 		case PRUNNING:
    723 		    (void) fprintf(cshout, format, "Running ");
    724 		    hadnl = 0;
    725 		    break;
    726 
    727 		case PINTERRUPTED:
    728 		case PSTOPPED:
    729 		case PSIGNALED:
    730                     /*
    731                      * tell what happened to the background job
    732                      * From: Michael Schroeder
    733                      * <mlschroe (at) immd4.informatik.uni-erlangen.de>
    734                      */
    735                     if ((flag & REASON)
    736                         || ((flag & AREASON)
    737                             && reason != SIGINT
    738                             && (reason != SIGPIPE
    739                                 || (pp->p_flags & PPOU) == 0))) {
    740 			(void) fprintf(cshout, format,
    741 				       sys_siglist[(unsigned char)
    742 						   pp->p_reason]);
    743 			hadnl = 0;
    744 		    }
    745 		    break;
    746 
    747 		case PNEXITED:
    748 		case PAEXITED:
    749 		    if (flag & REASON) {
    750 			if (pp->p_reason)
    751 			    (void) fprintf(cshout, "Exit %-18d", pp->p_reason);
    752 			else
    753 			    (void) fprintf(cshout, format, "Done");
    754 			hadnl = 0;
    755 		    }
    756 		    break;
    757 
    758 		default:
    759 		    (void) fprintf(csherr, "BUG: status=%-9o", status);
    760 		}
    761 	    }
    762 	}
    763 prcomd:
    764 	if (flag & NAME) {
    765 	    (void) fprintf(cshout, "%s", vis_str(pp->p_command));
    766 	    if (pp->p_flags & PPOU)
    767 		(void) fprintf(cshout, " |");
    768 	    if (pp->p_flags & PERR)
    769 		(void) fputc('&', cshout);
    770 	    hadnl = 0;
    771 	}
    772 	if (flag & (REASON | AREASON) && pp->p_flags & PDUMPED) {
    773 	    (void) fprintf(cshout, " (core dumped)");
    774 	    hadnl = 0;
    775 	}
    776 	if (tp == pp->p_friends) {
    777 	    if (flag & AMPERSAND) {
    778 		(void) fprintf(cshout, " &");
    779 		hadnl = 0;
    780 	    }
    781 	    if (flag & JOBDIR &&
    782 		!eq(tp->p_cwd->di_name, dcwd->di_name)) {
    783 		(void) fprintf(cshout, " (wd: ");
    784 		dtildepr(value(STRhome), tp->p_cwd->di_name);
    785 		(void) fputc(')', cshout);
    786 		hadnl = 0;
    787 	    }
    788 	}
    789 	if (pp->p_flags & PPTIME && !(status & (PSTOPPED | PRUNNING))) {
    790 	    if (!hadnl)
    791 		(void) fprintf(cshout, "\n\t");
    792 	    prusage(&zru, &pp->p_rusage, &pp->p_etime,
    793 		    &pp->p_btime);
    794 	    hadnl = 1;
    795 	}
    796 	if (tp == pp->p_friends) {
    797 	    if (!hadnl) {
    798 		(void) fputc('\n', cshout);
    799 		hadnl = 1;
    800 	    }
    801 	    if (flag & SHELLDIR && !eq(tp->p_cwd->di_name, dcwd->di_name)) {
    802 		(void) fprintf(cshout, "(wd now: ");
    803 		dtildepr(value(STRhome), dcwd->di_name);
    804 		(void) fprintf(cshout, ")\n");
    805 		hadnl = 1;
    806 	    }
    807 	}
    808     } while ((pp = pp->p_friends) != tp);
    809     if (jobflags & PTIME && (jobflags & (PSTOPPED | PRUNNING)) == 0) {
    810 	if (jobflags & NUMBER)
    811 	    (void) fprintf(cshout, "       ");
    812 	ptprint(tp);
    813 	hadnl = 1;
    814     }
    815     (void) fflush(cshout);
    816     return (jobflags);
    817 }
    818 
    819 static void
    820 ptprint(tp)
    821     register struct process *tp;
    822 {
    823     struct timeval tetime, diff;
    824     static struct timeval ztime;
    825     struct rusage ru;
    826     static struct rusage zru;
    827     register struct process *pp = tp;
    828 
    829     ru = zru;
    830     tetime = ztime;
    831     do {
    832 	ruadd(&ru, &pp->p_rusage);
    833 	tvsub(&diff, &pp->p_etime, &pp->p_btime);
    834 	if (timercmp(&diff, &tetime, >))
    835 	    tetime = diff;
    836     } while ((pp = pp->p_friends) != tp);
    837     prusage(&zru, &ru, &tetime, &ztime);
    838 }
    839 
    840 /*
    841  * dojobs - print all jobs
    842  */
    843 void
    844 /*ARGSUSED*/
    845 dojobs(v, t)
    846     Char **v;
    847     struct command *t;
    848 {
    849     register struct process *pp;
    850     register int flag = NUMBER | NAME | REASON;
    851     int     i;
    852 
    853     if (chkstop)
    854 	chkstop = 2;
    855     if (*++v) {
    856 	if (v[1] || !eq(*v, STRml))
    857 	    stderror(ERR_JOBS);
    858 	flag |= FANCY | JOBDIR;
    859     }
    860     for (i = 1; i <= pmaxindex; i++)
    861 	for (pp = proclist.p_next; pp; pp = pp->p_next)
    862 	    if (pp->p_index == i && pp->p_pid == pp->p_jobid) {
    863 		pp->p_flags &= ~PNEEDNOTE;
    864 		if (!(pprint(pp, flag) & (PRUNNING | PSTOPPED)))
    865 		    pflush(pp);
    866 		break;
    867 	    }
    868 }
    869 
    870 /*
    871  * dofg - builtin - put the job into the foreground
    872  */
    873 void
    874 /*ARGSUSED*/
    875 dofg(v, t)
    876     Char **v;
    877     struct command *t;
    878 {
    879     register struct process *pp;
    880 
    881     okpcntl();
    882     ++v;
    883     do {
    884 	pp = pfind(*v);
    885 	pstart(pp, 1);
    886 	pjwait(pp);
    887     } while (*v && *++v);
    888 }
    889 
    890 /*
    891  * %... - builtin - put the job into the foreground
    892  */
    893 void
    894 /*ARGSUSED*/
    895 dofg1(v, t)
    896     Char **v;
    897     struct command *t;
    898 {
    899     register struct process *pp;
    900 
    901     okpcntl();
    902     pp = pfind(v[0]);
    903     pstart(pp, 1);
    904     pjwait(pp);
    905 }
    906 
    907 /*
    908  * dobg - builtin - put the job into the background
    909  */
    910 void
    911 /*ARGSUSED*/
    912 dobg(v, t)
    913     Char **v;
    914     struct command *t;
    915 {
    916     register struct process *pp;
    917 
    918     okpcntl();
    919     ++v;
    920     do {
    921 	pp = pfind(*v);
    922 	pstart(pp, 0);
    923     } while (*v && *++v);
    924 }
    925 
    926 /*
    927  * %... & - builtin - put the job into the background
    928  */
    929 void
    930 /*ARGSUSED*/
    931 dobg1(v, t)
    932     Char **v;
    933     struct command *t;
    934 {
    935     register struct process *pp;
    936 
    937     pp = pfind(v[0]);
    938     pstart(pp, 0);
    939 }
    940 
    941 /*
    942  * dostop - builtin - stop the job
    943  */
    944 void
    945 /*ARGSUSED*/
    946 dostop(v, t)
    947     Char **v;
    948     struct command *t;
    949 {
    950     pkill(++v, SIGSTOP);
    951 }
    952 
    953 /*
    954  * dokill - builtin - superset of kill (1)
    955  */
    956 void
    957 /*ARGSUSED*/
    958 dokill(v, t)
    959     Char **v;
    960     struct command *t;
    961 {
    962     register int signum = SIGTERM;
    963     register char *name;
    964 
    965     v++;
    966     if (v[0] && v[0][0] == '-') {
    967 	if (v[0][1] == 'l') {
    968 	    for (signum = 1; signum < NSIG; signum++) {
    969 		(void) fprintf(cshout, "%s ", sys_signame[signum]);
    970 		if (signum == NSIG / 2)
    971 		    (void) fputc('\n', cshout);
    972 	    }
    973 	    (void) fputc('\n', cshout);
    974 	    return;
    975 	}
    976 	if (Isdigit(v[0][1])) {
    977 	    signum = atoi(short2str(v[0] + 1));
    978 	    if (signum < 0 || signum > NSIG)
    979 		stderror(ERR_NAME | ERR_BADSIG);
    980 	}
    981 	else {
    982 	    name = short2str(&v[0][1]);
    983 	    if (!strncasecmp(name, "sig", 3))
    984 		name += 3;
    985 
    986 	    for (signum = 1; signum < NSIG; signum++)
    987 		if (!strcasecmp(sys_signame[signum], name))
    988 		    break;
    989 
    990 	    if (signum == NSIG) {
    991 		setname(vis_str(&v[0][1]));
    992 		stderror(ERR_NAME | ERR_UNKSIG);
    993 	    }
    994 	}
    995 	v++;
    996     }
    997     pkill(v, signum);
    998 }
    999 
   1000 static void
   1001 pkill(v, signum)
   1002     Char  **v;
   1003     int     signum;
   1004 {
   1005     register struct process *pp, *np;
   1006     register int jobflags = 0;
   1007     int     pid, err1 = 0;
   1008     sigset_t omask;
   1009     Char   *cp;
   1010 
   1011     omask = sigmask(SIGCHLD);
   1012     if (setintr)
   1013 	omask |= sigmask(SIGINT);
   1014     omask = sigblock(omask) & ~omask;
   1015     gflag = 0, tglob(v);
   1016     if (gflag) {
   1017 	v = globall(v);
   1018 	if (v == 0)
   1019 	    stderror(ERR_NAME | ERR_NOMATCH);
   1020     }
   1021     else {
   1022 	v = gargv = saveblk(v);
   1023 	trim(v);
   1024     }
   1025 
   1026     while (v && (cp = *v)) {
   1027 	if (*cp == '%') {
   1028 	    np = pp = pfind(cp);
   1029 	    do
   1030 		jobflags |= np->p_flags;
   1031 	    while ((np = np->p_friends) != pp);
   1032 	    switch (signum) {
   1033 
   1034 	    case SIGSTOP:
   1035 	    case SIGTSTP:
   1036 	    case SIGTTIN:
   1037 	    case SIGTTOU:
   1038 		if ((jobflags & PRUNNING) == 0) {
   1039 		    (void) fprintf(csherr, "%s: Already suspended\n",
   1040 				   vis_str(cp));
   1041 		    err1++;
   1042 		    goto cont;
   1043 		}
   1044 		break;
   1045 		/*
   1046 		 * suspend a process, kill -CONT %, then type jobs; the shell
   1047 		 * says it is suspended, but it is running; thanks jaap..
   1048 		 */
   1049 	    case SIGCONT:
   1050 		pstart(pp, 0);
   1051 		goto cont;
   1052 	    }
   1053 	    if (killpg((pid_t) pp->p_jobid, signum) < 0) {
   1054 		(void) fprintf(csherr, "%s: %s\n", vis_str(cp),
   1055 			       strerror(errno));
   1056 		err1++;
   1057 	    }
   1058 	    if (signum == SIGTERM || signum == SIGHUP)
   1059 		(void) killpg((pid_t) pp->p_jobid, SIGCONT);
   1060 	}
   1061 	else if (!(Isdigit(*cp) || *cp == '-'))
   1062 	    stderror(ERR_NAME | ERR_JOBARGS);
   1063 	else {
   1064 	    pid = atoi(short2str(cp));
   1065 	    if (kill((pid_t) pid, signum) < 0) {
   1066 		(void) fprintf(csherr, "%d: %s\n", pid, strerror(errno));
   1067 		err1++;
   1068 		goto cont;
   1069 	    }
   1070 	    if (signum == SIGTERM || signum == SIGHUP)
   1071 		(void) kill((pid_t) pid, SIGCONT);
   1072 	}
   1073 cont:
   1074 	v++;
   1075     }
   1076     if (gargv)
   1077 	blkfree(gargv), gargv = 0;
   1078     (void) sigsetmask(omask);
   1079     if (err1)
   1080 	stderror(ERR_SILENT);
   1081 }
   1082 
   1083 /*
   1084  * pstart - start the job in foreground/background
   1085  */
   1086 void
   1087 pstart(pp, foregnd)
   1088     register struct process *pp;
   1089     int     foregnd;
   1090 {
   1091     register struct process *np;
   1092     sigset_t omask;
   1093     long    jobflags = 0;
   1094 
   1095     omask = sigblock(sigmask(SIGCHLD));
   1096     np = pp;
   1097     do {
   1098 	jobflags |= np->p_flags;
   1099 	if (np->p_flags & (PRUNNING | PSTOPPED)) {
   1100 	    np->p_flags |= PRUNNING;
   1101 	    np->p_flags &= ~PSTOPPED;
   1102 	    if (foregnd)
   1103 		np->p_flags |= PFOREGND;
   1104 	    else
   1105 		np->p_flags &= ~PFOREGND;
   1106 	}
   1107     } while ((np = np->p_friends) != pp);
   1108     if (!foregnd)
   1109 	pclrcurr(pp);
   1110     (void) pprint(pp, foregnd ? NAME | JOBDIR : NUMBER | NAME | AMPERSAND);
   1111     if (foregnd)
   1112 	(void) tcsetpgrp(FSHTTY, pp->p_jobid);
   1113     if (jobflags & PSTOPPED)
   1114 	(void) killpg((pid_t) pp->p_jobid, SIGCONT);
   1115     (void) sigsetmask(omask);
   1116 }
   1117 
   1118 void
   1119 panystop(neednl)
   1120     bool    neednl;
   1121 {
   1122     register struct process *pp;
   1123 
   1124     chkstop = 2;
   1125     for (pp = proclist.p_next; pp; pp = pp->p_next)
   1126 	if (pp->p_flags & PSTOPPED)
   1127 	    stderror(ERR_STOPPED, neednl ? "\n" : "");
   1128 }
   1129 
   1130 struct process *
   1131 pfind(cp)
   1132     Char   *cp;
   1133 {
   1134     register struct process *pp, *np;
   1135 
   1136     if (cp == 0 || cp[1] == 0 || eq(cp, STRcent2) || eq(cp, STRcentplus)) {
   1137 	if (pcurrent == NULL)
   1138 	    stderror(ERR_NAME | ERR_JOBCUR);
   1139 	return (pcurrent);
   1140     }
   1141     if (eq(cp, STRcentminus) || eq(cp, STRcenthash)) {
   1142 	if (pprevious == NULL)
   1143 	    stderror(ERR_NAME | ERR_JOBPREV);
   1144 	return (pprevious);
   1145     }
   1146     if (Isdigit(cp[1])) {
   1147 	int     idx = atoi(short2str(cp + 1));
   1148 
   1149 	for (pp = proclist.p_next; pp; pp = pp->p_next)
   1150 	    if (pp->p_index == idx && pp->p_pid == pp->p_jobid)
   1151 		return (pp);
   1152 	stderror(ERR_NAME | ERR_NOSUCHJOB);
   1153     }
   1154     np = NULL;
   1155     for (pp = proclist.p_next; pp; pp = pp->p_next)
   1156 	if (pp->p_pid == pp->p_jobid) {
   1157 	    if (cp[1] == '?') {
   1158 		register Char *dp;
   1159 
   1160 		for (dp = pp->p_command; *dp; dp++) {
   1161 		    if (*dp != cp[2])
   1162 			continue;
   1163 		    if (prefix(cp + 2, dp))
   1164 			goto match;
   1165 		}
   1166 	    }
   1167 	    else if (prefix(cp + 1, pp->p_command)) {
   1168 	match:
   1169 		if (np)
   1170 		    stderror(ERR_NAME | ERR_AMBIG);
   1171 		np = pp;
   1172 	    }
   1173 	}
   1174     if (np)
   1175 	return (np);
   1176     stderror(ERR_NAME | cp[1] == '?' ? ERR_JOBPAT : ERR_NOSUCHJOB);
   1177     /* NOTREACHED */
   1178     return (0);
   1179 }
   1180 
   1181 
   1182 /*
   1183  * pgetcurr - find most recent job that is not pp, preferably stopped
   1184  */
   1185 static struct process *
   1186 pgetcurr(pp)
   1187     register struct process *pp;
   1188 {
   1189     register struct process *np;
   1190     register struct process *xp = NULL;
   1191 
   1192     for (np = proclist.p_next; np; np = np->p_next)
   1193 	if (np != pcurrent && np != pp && np->p_pid &&
   1194 	    np->p_pid == np->p_jobid) {
   1195 	    if (np->p_flags & PSTOPPED)
   1196 		return (np);
   1197 	    if (xp == NULL)
   1198 		xp = np;
   1199 	}
   1200     return (xp);
   1201 }
   1202 
   1203 /*
   1204  * donotify - flag the job so as to report termination asynchronously
   1205  */
   1206 void
   1207 /*ARGSUSED*/
   1208 donotify(v, t)
   1209     Char **v;
   1210     struct command *t;
   1211 {
   1212     register struct process *pp;
   1213 
   1214     pp = pfind(*++v);
   1215     pp->p_flags |= PNOTIFY;
   1216 }
   1217 
   1218 /*
   1219  * Do the fork and whatever should be done in the child side that
   1220  * should not be done if we are not forking at all (like for simple builtin's)
   1221  * Also do everything that needs any signals fiddled with in the parent side
   1222  *
   1223  * Wanttty tells whether process and/or tty pgrps are to be manipulated:
   1224  *	-1:	leave tty alone; inherit pgrp from parent
   1225  *	 0:	already have tty; manipulate process pgrps only
   1226  *	 1:	want to claim tty; manipulate process and tty pgrps
   1227  * It is usually just the value of tpgrp.
   1228  */
   1229 
   1230 int
   1231 pfork(t, wanttty)
   1232     struct command *t;		/* command we are forking for */
   1233     int     wanttty;
   1234 {
   1235     register int pid;
   1236     bool    ignint = 0;
   1237     int     pgrp;
   1238     sigset_t omask;
   1239 
   1240     /*
   1241      * A child will be uninterruptible only under very special conditions.
   1242      * Remember that the semantics of '&' is implemented by disconnecting the
   1243      * process from the tty so signals do not need to ignored just for '&'.
   1244      * Thus signals are set to default action for children unless: we have had
   1245      * an "onintr -" (then specifically ignored) we are not playing with
   1246      * signals (inherit action)
   1247      */
   1248     if (setintr)
   1249 	ignint = (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT))
   1250 	    || (gointr && eq(gointr, STRminus));
   1251     /*
   1252      * Check for maximum nesting of 16 processes to avoid Forking loops
   1253      */
   1254     if (child == 16)
   1255 	stderror(ERR_NESTING, 16);
   1256     /*
   1257      * Hold SIGCHLD until we have the process installed in our table.
   1258      */
   1259     omask = sigblock(sigmask(SIGCHLD));
   1260     while ((pid = fork()) < 0)
   1261 	if (setintr == 0)
   1262 	    (void) sleep(FORKSLEEP);
   1263 	else {
   1264 	    (void) sigsetmask(omask);
   1265 	    stderror(ERR_NOPROC);
   1266 	}
   1267     if (pid == 0) {
   1268 	settimes();
   1269 	pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
   1270 	pflushall();
   1271 	pcurrjob = NULL;
   1272 	child++;
   1273 	if (setintr) {
   1274 	    setintr = 0;	/* until I think otherwise */
   1275 	    /*
   1276 	     * Children just get blown away on SIGINT, SIGQUIT unless "onintr
   1277 	     * -" seen.
   1278 	     */
   1279 	    (void) signal(SIGINT, ignint ? SIG_IGN : SIG_DFL);
   1280 	    (void) signal(SIGQUIT, ignint ? SIG_IGN : SIG_DFL);
   1281 	    if (wanttty >= 0) {
   1282 		/* make stoppable */
   1283 		(void) signal(SIGTSTP, SIG_DFL);
   1284 		(void) signal(SIGTTIN, SIG_DFL);
   1285 		(void) signal(SIGTTOU, SIG_DFL);
   1286 	    }
   1287 	    (void) signal(SIGTERM, parterm);
   1288 	}
   1289 	else if (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT)) {
   1290 	    (void) signal(SIGINT, SIG_IGN);
   1291 	    (void) signal(SIGQUIT, SIG_IGN);
   1292 	}
   1293 	pgetty(wanttty, pgrp);
   1294 	/*
   1295 	 * Nohup and nice apply only to NODE_COMMAND's but it would be nice
   1296 	 * (?!?) if you could say "nohup (foo;bar)" Then the parser would have
   1297 	 * to know about nice/nohup/time
   1298 	 */
   1299 	if (t->t_dflg & F_NOHUP)
   1300 	    (void) signal(SIGHUP, SIG_IGN);
   1301 	if (t->t_dflg & F_NICE)
   1302 	    (void) setpriority(PRIO_PROCESS, 0, t->t_nice);
   1303     }
   1304     else {
   1305 	if (wanttty >= 0)
   1306 	    (void) setpgid(pid, pcurrjob ? pcurrjob->p_jobid : pid);
   1307 	palloc(pid, t);
   1308 	(void) sigsetmask(omask);
   1309     }
   1310 
   1311     return (pid);
   1312 }
   1313 
   1314 static void
   1315 okpcntl()
   1316 {
   1317     if (tpgrp == -1)
   1318 	stderror(ERR_JOBCONTROL);
   1319     if (tpgrp == 0)
   1320 	stderror(ERR_JOBCTRLSUB);
   1321 }
   1322 
   1323 /*
   1324  * if we don't have vfork(), things can still go in the wrong order
   1325  * resulting in the famous 'Stopped (tty output)'. But some systems
   1326  * don't permit the setpgid() call, (these are more recent secure
   1327  * systems such as ibm's aix). Then we'd rather print an error message
   1328  * than hang the shell!
   1329  * I am open to suggestions how to fix that.
   1330  */
   1331 void
   1332 pgetty(wanttty, pgrp)
   1333     int     wanttty, pgrp;
   1334 {
   1335     sigset_t omask = 0;
   1336 
   1337     /*
   1338      * christos: I am blocking the tty signals till I've set things
   1339      * correctly....
   1340      */
   1341     if (wanttty > 0)
   1342 	omask = sigblock(sigmask(SIGTSTP)|sigmask(SIGTTIN)|sigmask(SIGTTOU));
   1343     /*
   1344      * From: Michael Schroeder <mlschroe (at) immd4.informatik.uni-erlangen.de>
   1345      * Don't check for tpgrp >= 0 so even non-interactive shells give
   1346      * background jobs process groups Same for the comparison in the other part
   1347      * of the #ifdef
   1348      */
   1349     if (wanttty >= 0)
   1350 	if (setpgid(0, pgrp) == -1) {
   1351 	    (void) fprintf(csherr, "csh: setpgid error.\n");
   1352 	    xexit(0);
   1353 	}
   1354 
   1355     if (wanttty > 0) {
   1356 	(void) tcsetpgrp(FSHTTY, pgrp);
   1357 	(void) sigsetmask(omask);
   1358     }
   1359 
   1360     if (tpgrp > 0)
   1361 	tpgrp = 0;		/* gave tty away */
   1362 }
   1363