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proc.c revision 1.11
      1 /*	$NetBSD: proc.c,v 1.11 1997/07/04 21:24:07 christos 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 #include <sys/cdefs.h>
     37 #ifndef lint
     38 #if 0
     39 static char sccsid[] = "@(#)proc.c	8.1 (Berkeley) 5/31/93";
     40 #else
     41 __RCSID("$NetBSD: proc.c,v 1.11 1997/07/04 21:24:07 christos Exp $");
     42 #endif
     43 #endif /* not lint */
     44 
     45 #include <sys/types.h>
     46 #include <sys/wait.h>
     47 #include <errno.h>
     48 #include <unistd.h>
     49 #include <stdlib.h>
     50 #include <string.h>
     51 #if __STDC__
     52 # include <stdarg.h>
     53 #else
     54 # include <varargs.h>
     55 #endif
     56 
     57 #include "csh.h"
     58 #include "dir.h"
     59 #include "proc.h"
     60 #include "extern.h"
     61 
     62 #define BIGINDEX	9	/* largest desirable job index */
     63 
     64 static struct rusage zru;
     65 
     66 static void	 pflushall __P((void));
     67 static void	 pflush __P((struct process *));
     68 static void	 pclrcurr __P((struct process *));
     69 static void	 padd __P((struct command *));
     70 static int	 pprint __P((struct process *, int));
     71 static void	 ptprint __P((struct process *));
     72 static void	 pads __P((Char *));
     73 static void	 pkill __P((Char **v, int));
     74 static struct	process
     75 		*pgetcurr __P((struct process *));
     76 static void	 okpcntl __P((void));
     77 
     78 /*
     79  * pchild - called at interrupt level by the SIGCHLD signal
     80  *	indicating that at least one child has terminated or stopped
     81  *	thus at least one wait system call will definitely return a
     82  *	childs status.  Top level routines (like pwait) must be sure
     83  *	to mask interrupts when playing with the proclist data structures!
     84  */
     85 /* ARGUSED */
     86 void
     87 pchild(notused)
     88 	int notused;
     89 {
     90     struct process *pp;
     91     struct process *fp;
     92     int pid;
     93     extern int insource;
     94     union wait w;
     95     int     jobflags;
     96     struct rusage ru;
     97 
     98 loop:
     99     errno = 0;			/* reset, just in case */
    100     pid = wait3(&w.w_status,
    101        (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG), &ru);
    102 
    103     if (pid <= 0) {
    104 	if (errno == EINTR) {
    105 	    errno = 0;
    106 	    goto loop;
    107 	}
    108 	pnoprocesses = pid == -1;
    109 	return;
    110     }
    111     for (pp = proclist.p_next; pp != NULL; pp = pp->p_next)
    112 	if (pid == pp->p_pid)
    113 	    goto found;
    114     goto loop;
    115 found:
    116     if (pid == atoi(short2str(value(STRchild))))
    117 	unsetv(STRchild);
    118     pp->p_flags &= ~(PRUNNING | PSTOPPED | PREPORTED);
    119     if (WIFSTOPPED(w)) {
    120 	pp->p_flags |= PSTOPPED;
    121 	pp->p_reason = w.w_stopsig;
    122     }
    123     else {
    124 	if (pp->p_flags & (PTIME | PPTIME) || adrof(STRtime))
    125 	    (void) gettimeofday(&pp->p_etime, NULL);
    126 
    127 	pp->p_rusage = ru;
    128 	if (WIFSIGNALED(w)) {
    129 	    if (w.w_termsig == SIGINT)
    130 		pp->p_flags |= PINTERRUPTED;
    131 	    else
    132 		pp->p_flags |= PSIGNALED;
    133 	    if (w.w_coredump)
    134 		pp->p_flags |= PDUMPED;
    135 	    pp->p_reason = w.w_termsig;
    136 	}
    137 	else {
    138 	    pp->p_reason = w.w_retcode;
    139 	    if (pp->p_reason != 0)
    140 		pp->p_flags |= PAEXITED;
    141 	    else
    142 		pp->p_flags |= PNEXITED;
    143 	}
    144     }
    145     jobflags = 0;
    146     fp = pp;
    147     do {
    148 	if ((fp->p_flags & (PPTIME | PRUNNING | PSTOPPED)) == 0 &&
    149 	    !child && adrof(STRtime) &&
    150 	    fp->p_rusage.ru_utime.tv_sec + fp->p_rusage.ru_stime.tv_sec
    151 	    >= atoi(short2str(value(STRtime))))
    152 	    fp->p_flags |= PTIME;
    153 	jobflags |= fp->p_flags;
    154     } while ((fp = fp->p_friends) != pp);
    155     pp->p_flags &= ~PFOREGND;
    156     if (pp == pp->p_friends && (pp->p_flags & PPTIME)) {
    157 	pp->p_flags &= ~PPTIME;
    158 	pp->p_flags |= PTIME;
    159     }
    160     if ((jobflags & (PRUNNING | PREPORTED)) == 0) {
    161 	fp = pp;
    162 	do {
    163 	    if (fp->p_flags & PSTOPPED)
    164 		fp->p_flags |= PREPORTED;
    165 	} while ((fp = fp->p_friends) != pp);
    166 	while (fp->p_pid != fp->p_jobid)
    167 	    fp = fp->p_friends;
    168 	if (jobflags & PSTOPPED) {
    169 	    if (pcurrent && pcurrent != fp)
    170 		pprevious = pcurrent;
    171 	    pcurrent = fp;
    172 	}
    173 	else
    174 	    pclrcurr(fp);
    175 	if (jobflags & PFOREGND) {
    176 	    if (jobflags & (PSIGNALED | PSTOPPED | PPTIME) ||
    177 #ifdef IIASA
    178 		jobflags & PAEXITED ||
    179 #endif
    180 		!eq(dcwd->di_name, fp->p_cwd->di_name)) {
    181 		;		/* print in pjwait */
    182 	    }
    183 	    /* PWP: print a newline after ^C */
    184 	    else if (jobflags & PINTERRUPTED) {
    185 		(void) vis_fputc('\r' | QUOTE, cshout);
    186 		(void) fputc('\n', cshout);
    187 	    }
    188 	}
    189 	else {
    190 	    if (jobflags & PNOTIFY || adrof(STRnotify)) {
    191 		(void) vis_fputc('\r' | QUOTE, cshout);
    192 		(void) fputc('\n', cshout);
    193 		(void) pprint(pp, NUMBER | NAME | REASON);
    194 		if ((jobflags & PSTOPPED) == 0)
    195 		    pflush(pp);
    196 	    }
    197 	    else {
    198 		fp->p_flags |= PNEEDNOTE;
    199 		neednote++;
    200 	    }
    201 	}
    202     }
    203     goto loop;
    204 }
    205 
    206 void
    207 pnote()
    208 {
    209     struct process *pp;
    210     int     flags;
    211     sigset_t sigset, osigset;
    212 
    213     neednote = 0;
    214     sigemptyset(&sigset);
    215     sigaddset(&sigset, SIGCHLD);
    216     for (pp = proclist.p_next; pp != NULL; pp = pp->p_next) {
    217 	if (pp->p_flags & PNEEDNOTE) {
    218 	    sigprocmask(SIG_BLOCK, &sigset, &osigset);
    219 	    pp->p_flags &= ~PNEEDNOTE;
    220 	    flags = pprint(pp, NUMBER | NAME | REASON);
    221 	    if ((flags & (PRUNNING | PSTOPPED)) == 0)
    222 		pflush(pp);
    223 	    sigprocmask(SIG_SETMASK, &osigset, NULL);
    224 	}
    225     }
    226 }
    227 
    228 /*
    229  * pwait - wait for current job to terminate, maintaining integrity
    230  *	of current and previous job indicators.
    231  */
    232 void
    233 pwait()
    234 {
    235     struct process *fp, *pp;
    236     sigset_t sigset, osigset;
    237 
    238     /*
    239      * Here's where dead procs get flushed.
    240      */
    241     sigemptyset(&sigset);
    242     sigaddset(&sigset, SIGCHLD);
    243     sigprocmask(SIG_BLOCK, &sigset, &osigset);
    244     for (pp = (fp = &proclist)->p_next; pp != NULL; pp = (fp = pp)->p_next)
    245 	if (pp->p_pid == 0) {
    246 	    fp->p_next = pp->p_next;
    247 	    xfree((ptr_t) pp->p_command);
    248 	    if (pp->p_cwd && --pp->p_cwd->di_count == 0)
    249 		if (pp->p_cwd->di_next == 0)
    250 		    dfree(pp->p_cwd);
    251 	    xfree((ptr_t) pp);
    252 	    pp = fp;
    253 	}
    254     sigprocmask(SIG_SETMASK, &osigset, NULL);
    255     pjwait(pcurrjob);
    256 }
    257 
    258 
    259 /*
    260  * pjwait - wait for a job to finish or become stopped
    261  *	It is assumed to be in the foreground state (PFOREGND)
    262  */
    263 void
    264 pjwait(pp)
    265     struct process *pp;
    266 {
    267     struct process *fp;
    268     int     jobflags, reason;
    269     sigset_t sigset, osigset;
    270 
    271     while (pp->p_pid != pp->p_jobid)
    272 	pp = pp->p_friends;
    273     fp = pp;
    274 
    275     do {
    276 	if ((fp->p_flags & (PFOREGND | PRUNNING)) == PRUNNING)
    277 	    (void) fprintf(csherr, "BUG: waiting for background job!\n");
    278     } while ((fp = fp->p_friends) != pp);
    279     /*
    280      * Now keep pausing as long as we are not interrupted (SIGINT), and the
    281      * target process, or any of its friends, are running
    282      */
    283     fp = pp;
    284     sigemptyset(&sigset);
    285     sigaddset(&sigset, SIGCHLD);
    286     sigprocmask(SIG_BLOCK, &sigset, &osigset);
    287     for (;;) {
    288 	sigemptyset(&sigset);
    289 	sigaddset(&sigset, SIGCHLD);
    290 	sigprocmask(SIG_BLOCK, &sigset, NULL);
    291 	jobflags = 0;
    292 	do
    293 	    jobflags |= fp->p_flags;
    294 	while ((fp = (fp->p_friends)) != pp);
    295 	if ((jobflags & PRUNNING) == 0)
    296 	    break;
    297 #ifdef JOBDEBUG
    298 	(void) fprintf(csherr, "starting to sigsuspend for  SIGCHLD on %d\n",
    299 		       fp->p_pid);
    300 #endif				/* JOBDEBUG */
    301 	sigset = osigset;
    302 	sigdelset(&sigset, SIGCHLD);
    303 	sigsuspend(&sigset);
    304     }
    305     sigprocmask(SIG_SETMASK, &osigset, NULL);
    306     if (tpgrp > 0)		/* get tty back */
    307 	(void) tcsetpgrp(FSHTTY, tpgrp);
    308     if ((jobflags & (PSIGNALED | PSTOPPED | PTIME)) ||
    309 	!eq(dcwd->di_name, fp->p_cwd->di_name)) {
    310 	if (jobflags & PSTOPPED) {
    311 	    (void) fputc('\n', cshout);
    312 	    if (adrof(STRlistjobs)) {
    313 		Char   *jobcommand[3];
    314 
    315 		jobcommand[0] = STRjobs;
    316 		if (eq(value(STRlistjobs), STRlong))
    317 		    jobcommand[1] = STRml;
    318 		else
    319 		    jobcommand[1] = NULL;
    320 		jobcommand[2] = NULL;
    321 
    322 		dojobs(jobcommand, NULL);
    323 		(void) pprint(pp, SHELLDIR);
    324 	    }
    325 	    else
    326 		(void) pprint(pp, AREASON | SHELLDIR);
    327 	}
    328 	else
    329 	    (void) pprint(pp, AREASON | SHELLDIR);
    330     }
    331     if ((jobflags & (PINTERRUPTED | PSTOPPED)) && setintr &&
    332 	(!gointr || !eq(gointr, STRminus))) {
    333 	if ((jobflags & PSTOPPED) == 0)
    334 	    pflush(pp);
    335 	pintr1(0);
    336 	/* NOTREACHED */
    337     }
    338     reason = 0;
    339     fp = pp;
    340     do {
    341 	if (fp->p_reason)
    342 	    reason = fp->p_flags & (PSIGNALED | PINTERRUPTED) ?
    343 		fp->p_reason | META : fp->p_reason;
    344     } while ((fp = fp->p_friends) != pp);
    345     if ((reason != 0) && (adrof(STRprintexitvalue))) {
    346 	(void) fprintf(cshout, "Exit %d\n", reason);
    347     }
    348     set(STRstatus, putn(reason));
    349     if (reason && exiterr)
    350 	exitstat();
    351     pflush(pp);
    352 }
    353 
    354 /*
    355  * dowait - wait for all processes to finish
    356  */
    357 void
    358 /*ARGSUSED*/
    359 dowait(v, t)
    360     Char **v;
    361     struct command *t;
    362 {
    363     struct process *pp;
    364     sigset_t sigset, osigset;
    365 
    366     pjobs++;
    367     sigemptyset(&sigset);
    368     sigaddset(&sigset, SIGCHLD);
    369     sigprocmask(SIG_BLOCK, &sigset, &osigset);
    370 loop:
    371     for (pp = proclist.p_next; pp; pp = pp->p_next)
    372 	if (pp->p_pid &&	/* pp->p_pid == pp->p_jobid && */
    373 	    pp->p_flags & PRUNNING) {
    374 	    sigemptyset(&sigset);
    375 	    sigsuspend(&sigset);
    376 	    goto loop;
    377 	}
    378     sigprocmask(SIG_SETMASK, &osigset, NULL);
    379     pjobs = 0;
    380 }
    381 
    382 /*
    383  * pflushall - flush all jobs from list (e.g. at fork())
    384  */
    385 static void
    386 pflushall()
    387 {
    388     struct process *pp;
    389 
    390     for (pp = proclist.p_next; pp != NULL; pp = pp->p_next)
    391 	if (pp->p_pid)
    392 	    pflush(pp);
    393 }
    394 
    395 /*
    396  * pflush - flag all process structures in the same job as the
    397  *	the argument process for deletion.  The actual free of the
    398  *	space is not done here since pflush is called at interrupt level.
    399  */
    400 static void
    401 pflush(pp)
    402     struct process *pp;
    403 {
    404     struct process *np;
    405     int idx;
    406 
    407     if (pp->p_pid == 0) {
    408 	(void) fprintf(csherr, "BUG: process flushed twice");
    409 	return;
    410     }
    411     while (pp->p_pid != pp->p_jobid)
    412 	pp = pp->p_friends;
    413     pclrcurr(pp);
    414     if (pp == pcurrjob)
    415 	pcurrjob = 0;
    416     idx = pp->p_index;
    417     np = pp;
    418     do {
    419 	np->p_index = np->p_pid = 0;
    420 	np->p_flags &= ~PNEEDNOTE;
    421     } while ((np = np->p_friends) != pp);
    422     if (idx == pmaxindex) {
    423 	for (np = proclist.p_next, idx = 0; np; np = np->p_next)
    424 	    if (np->p_index > idx)
    425 		idx = np->p_index;
    426 	pmaxindex = idx;
    427     }
    428 }
    429 
    430 /*
    431  * pclrcurr - make sure the given job is not the current or previous job;
    432  *	pp MUST be the job leader
    433  */
    434 static void
    435 pclrcurr(pp)
    436     struct process *pp;
    437 {
    438 
    439     if (pp == pcurrent)
    440 	if (pprevious != NULL) {
    441 	    pcurrent = pprevious;
    442 	    pprevious = pgetcurr(pp);
    443 	}
    444 	else {
    445 	    pcurrent = pgetcurr(pp);
    446 	    pprevious = pgetcurr(pp);
    447 	}
    448     else if (pp == pprevious)
    449 	pprevious = pgetcurr(pp);
    450 }
    451 
    452 /* +4 here is 1 for '\0', 1 ea for << >& >> */
    453 static Char command[PMAXLEN + 4];
    454 static int cmdlen;
    455 static Char *cmdp;
    456 
    457 /*
    458  * palloc - allocate a process structure and fill it up.
    459  *	an important assumption is made that the process is running.
    460  */
    461 void
    462 palloc(pid, t)
    463     int     pid;
    464     struct command *t;
    465 {
    466     struct process *pp;
    467     int     i;
    468 
    469     pp = (struct process *) xcalloc(1, (size_t) sizeof(struct process));
    470     pp->p_pid = pid;
    471     pp->p_flags = t->t_dflg & F_AMPERSAND ? PRUNNING : PRUNNING | PFOREGND;
    472     if (t->t_dflg & F_TIME)
    473 	pp->p_flags |= PPTIME;
    474     cmdp = command;
    475     cmdlen = 0;
    476     padd(t);
    477     *cmdp++ = 0;
    478     if (t->t_dflg & F_PIPEOUT) {
    479 	pp->p_flags |= PPOU;
    480 	if (t->t_dflg & F_STDERR)
    481 	    pp->p_flags |= PERR;
    482     }
    483     pp->p_command = Strsave(command);
    484     if (pcurrjob) {
    485 	struct process *fp;
    486 
    487 	/* careful here with interrupt level */
    488 	pp->p_cwd = 0;
    489 	pp->p_index = pcurrjob->p_index;
    490 	pp->p_friends = pcurrjob;
    491 	pp->p_jobid = pcurrjob->p_pid;
    492 	for (fp = pcurrjob; fp->p_friends != pcurrjob; fp = fp->p_friends)
    493 	    continue;
    494 	fp->p_friends = pp;
    495     }
    496     else {
    497 	pcurrjob = pp;
    498 	pp->p_jobid = pid;
    499 	pp->p_friends = pp;
    500 	pp->p_cwd = dcwd;
    501 	dcwd->di_count++;
    502 	if (pmaxindex < BIGINDEX)
    503 	    pp->p_index = ++pmaxindex;
    504 	else {
    505 	    struct process *np;
    506 
    507 	    for (i = 1;; i++) {
    508 		for (np = proclist.p_next; np; np = np->p_next)
    509 		    if (np->p_index == i)
    510 			goto tryagain;
    511 		pp->p_index = i;
    512 		if (i > pmaxindex)
    513 		    pmaxindex = i;
    514 		break;
    515 	tryagain:;
    516 	    }
    517 	}
    518 	if (pcurrent == NULL)
    519 	    pcurrent = pp;
    520 	else if (pprevious == NULL)
    521 	    pprevious = pp;
    522     }
    523     pp->p_next = proclist.p_next;
    524     proclist.p_next = pp;
    525     (void) gettimeofday(&pp->p_btime, NULL);
    526 }
    527 
    528 static void
    529 padd(t)
    530     struct command *t;
    531 {
    532     Char  **argp;
    533 
    534     if (t == 0)
    535 	return;
    536     switch (t->t_dtyp) {
    537 
    538     case NODE_PAREN:
    539 	pads(STRLparensp);
    540 	padd(t->t_dspr);
    541 	pads(STRspRparen);
    542 	break;
    543 
    544     case NODE_COMMAND:
    545 	for (argp = t->t_dcom; *argp; argp++) {
    546 	    pads(*argp);
    547 	    if (argp[1])
    548 		pads(STRspace);
    549 	}
    550 	break;
    551 
    552     case NODE_OR:
    553     case NODE_AND:
    554     case NODE_PIPE:
    555     case NODE_LIST:
    556 	padd(t->t_dcar);
    557 	switch (t->t_dtyp) {
    558 	case NODE_OR:
    559 	    pads(STRspor2sp);
    560 	    break;
    561 	case NODE_AND:
    562 	    pads(STRspand2sp);
    563 	    break;
    564 	case NODE_PIPE:
    565 	    pads(STRsporsp);
    566 	    break;
    567 	case NODE_LIST:
    568 	    pads(STRsemisp);
    569 	    break;
    570 	}
    571 	padd(t->t_dcdr);
    572 	return;
    573     }
    574     if ((t->t_dflg & F_PIPEIN) == 0 && t->t_dlef) {
    575 	pads((t->t_dflg & F_READ) ? STRspLarrow2sp : STRspLarrowsp);
    576 	pads(t->t_dlef);
    577     }
    578     if ((t->t_dflg & F_PIPEOUT) == 0 && t->t_drit) {
    579 	pads((t->t_dflg & F_APPEND) ? STRspRarrow2 : STRspRarrow);
    580 	if (t->t_dflg & F_STDERR)
    581 	    pads(STRand);
    582 	pads(STRspace);
    583 	pads(t->t_drit);
    584     }
    585 }
    586 
    587 static void
    588 pads(cp)
    589     Char   *cp;
    590 {
    591     int i;
    592 
    593     /*
    594      * Avoid the Quoted Space alias hack! Reported by:
    595      * sam (at) john-bigboote.ICS.UCI.EDU (Sam Horrocks)
    596      */
    597     if (cp[0] == STRQNULL[0])
    598 	cp++;
    599 
    600     i = Strlen(cp);
    601 
    602     if (cmdlen >= PMAXLEN)
    603 	return;
    604     if (cmdlen + i >= PMAXLEN) {
    605 	(void) Strcpy(cmdp, STRsp3dots);
    606 	cmdlen = PMAXLEN;
    607 	cmdp += 4;
    608 	return;
    609     }
    610     (void) Strcpy(cmdp, cp);
    611     cmdp += i;
    612     cmdlen += i;
    613 }
    614 
    615 /*
    616  * psavejob - temporarily save the current job on a one level stack
    617  *	so another job can be created.  Used for { } in exp6
    618  *	and `` in globbing.
    619  */
    620 void
    621 psavejob()
    622 {
    623 
    624     pholdjob = pcurrjob;
    625     pcurrjob = NULL;
    626 }
    627 
    628 /*
    629  * prestjob - opposite of psavejob.  This may be missed if we are interrupted
    630  *	somewhere, but pendjob cleans up anyway.
    631  */
    632 void
    633 prestjob()
    634 {
    635 
    636     pcurrjob = pholdjob;
    637     pholdjob = NULL;
    638 }
    639 
    640 /*
    641  * pendjob - indicate that a job (set of commands) has been completed
    642  *	or is about to begin.
    643  */
    644 void
    645 pendjob()
    646 {
    647     struct process *pp, *tp;
    648 
    649     if (pcurrjob && (pcurrjob->p_flags & (PFOREGND | PSTOPPED)) == 0) {
    650 	pp = pcurrjob;
    651 	while (pp->p_pid != pp->p_jobid)
    652 	    pp = pp->p_friends;
    653 	(void) fprintf(cshout, "[%d]", pp->p_index);
    654 	tp = pp;
    655 	do {
    656 	    (void) fprintf(cshout, " %d", pp->p_pid);
    657 	    pp = pp->p_friends;
    658 	} while (pp != tp);
    659 	(void) fputc('\n', cshout);
    660     }
    661     pholdjob = pcurrjob = 0;
    662 }
    663 
    664 /*
    665  * pprint - print a job
    666  */
    667 static int
    668 pprint(pp, flag)
    669     struct process *pp;
    670     bool    flag;
    671 {
    672     int status, reason;
    673     struct process *tp;
    674     int     jobflags, pstatus;
    675     bool hadnl = 1;	/* did we just have a newline */
    676     char   *format;
    677 
    678     (void) fpurge(cshout);
    679 
    680     while (pp->p_pid != pp->p_jobid)
    681 	pp = pp->p_friends;
    682     if (pp == pp->p_friends && (pp->p_flags & PPTIME)) {
    683 	pp->p_flags &= ~PPTIME;
    684 	pp->p_flags |= PTIME;
    685     }
    686     tp = pp;
    687     status = reason = -1;
    688     jobflags = 0;
    689     do {
    690 	jobflags |= pp->p_flags;
    691 	pstatus = pp->p_flags & PALLSTATES;
    692 	if (tp != pp && !hadnl && !(flag & FANCY) &&
    693 	    ((pstatus == status && pp->p_reason == reason) ||
    694 	     !(flag & REASON))) {
    695 	    (void) fputc(' ', cshout);
    696 	    hadnl = 0;
    697 	}
    698 	else {
    699 	    if (tp != pp && !hadnl) {
    700 		(void) fputc('\n', cshout);
    701 		hadnl = 1;
    702 	    }
    703 	    if (flag & NUMBER) {
    704 		if (pp == tp)
    705 		    (void) fprintf(cshout, "[%d]%s %c ", pp->p_index,
    706 			    pp->p_index < 10 ? " " : "",
    707 			    pp == pcurrent ? '+' :
    708 			    (pp == pprevious ? '-' : ' '));
    709 		else
    710 		    (void) fprintf(cshout, "       ");
    711 		hadnl = 0;
    712 	    }
    713 	    if (flag & FANCY) {
    714 		(void) fprintf(cshout, "%5d ", pp->p_pid);
    715 		hadnl = 0;
    716 	    }
    717 	    if (flag & (REASON | AREASON)) {
    718 		if (flag & NAME)
    719 		    format = "%-23s";
    720 		else
    721 		    format = "%s";
    722 		if (pstatus == status)
    723 		    if (pp->p_reason == reason) {
    724 			(void) fprintf(cshout, format, "");
    725 			hadnl = 0;
    726 			goto prcomd;
    727 		    }
    728 		    else
    729 			reason = pp->p_reason;
    730 		else {
    731 		    status = pstatus;
    732 		    reason = pp->p_reason;
    733 		}
    734 		switch (status) {
    735 
    736 		case PRUNNING:
    737 		    (void) fprintf(cshout, format, "Running ");
    738 		    hadnl = 0;
    739 		    break;
    740 
    741 		case PINTERRUPTED:
    742 		case PSTOPPED:
    743 		case PSIGNALED:
    744                     /*
    745                      * tell what happened to the background job
    746                      * From: Michael Schroeder
    747                      * <mlschroe (at) immd4.informatik.uni-erlangen.de>
    748                      */
    749                     if ((flag & REASON)
    750                         || ((flag & AREASON)
    751                             && reason != SIGINT
    752                             && (reason != SIGPIPE
    753                                 || (pp->p_flags & PPOU) == 0))) {
    754 			(void) fprintf(cshout, format,
    755 				       sys_siglist[(unsigned char)
    756 						   pp->p_reason]);
    757 			hadnl = 0;
    758 		    }
    759 		    break;
    760 
    761 		case PNEXITED:
    762 		case PAEXITED:
    763 		    if (flag & REASON) {
    764 			if (pp->p_reason)
    765 			    (void) fprintf(cshout, "Exit %-18d", pp->p_reason);
    766 			else
    767 			    (void) fprintf(cshout, format, "Done");
    768 			hadnl = 0;
    769 		    }
    770 		    break;
    771 
    772 		default:
    773 		    (void) fprintf(csherr, "BUG: status=%-9o", status);
    774 		}
    775 	    }
    776 	}
    777 prcomd:
    778 	if (flag & NAME) {
    779 	    (void) fprintf(cshout, "%s", vis_str(pp->p_command));
    780 	    if (pp->p_flags & PPOU)
    781 		(void) fprintf(cshout, " |");
    782 	    if (pp->p_flags & PERR)
    783 		(void) fputc('&', cshout);
    784 	    hadnl = 0;
    785 	}
    786 	if (flag & (REASON | AREASON) && pp->p_flags & PDUMPED) {
    787 	    (void) fprintf(cshout, " (core dumped)");
    788 	    hadnl = 0;
    789 	}
    790 	if (tp == pp->p_friends) {
    791 	    if (flag & AMPERSAND) {
    792 		(void) fprintf(cshout, " &");
    793 		hadnl = 0;
    794 	    }
    795 	    if (flag & JOBDIR &&
    796 		!eq(tp->p_cwd->di_name, dcwd->di_name)) {
    797 		(void) fprintf(cshout, " (wd: ");
    798 		dtildepr(value(STRhome), tp->p_cwd->di_name);
    799 		(void) fputc(')', cshout);
    800 		hadnl = 0;
    801 	    }
    802 	}
    803 	if (pp->p_flags & PPTIME && !(status & (PSTOPPED | PRUNNING))) {
    804 	    if (!hadnl)
    805 		(void) fprintf(cshout, "\n\t");
    806 	    prusage(&zru, &pp->p_rusage, &pp->p_etime,
    807 		    &pp->p_btime);
    808 	    hadnl = 1;
    809 	}
    810 	if (tp == pp->p_friends) {
    811 	    if (!hadnl) {
    812 		(void) fputc('\n', cshout);
    813 		hadnl = 1;
    814 	    }
    815 	    if (flag & SHELLDIR && !eq(tp->p_cwd->di_name, dcwd->di_name)) {
    816 		(void) fprintf(cshout, "(wd now: ");
    817 		dtildepr(value(STRhome), dcwd->di_name);
    818 		(void) fprintf(cshout, ")\n");
    819 		hadnl = 1;
    820 	    }
    821 	}
    822     } while ((pp = pp->p_friends) != tp);
    823     if (jobflags & PTIME && (jobflags & (PSTOPPED | PRUNNING)) == 0) {
    824 	if (jobflags & NUMBER)
    825 	    (void) fprintf(cshout, "       ");
    826 	ptprint(tp);
    827 	hadnl = 1;
    828     }
    829     (void) fflush(cshout);
    830     return (jobflags);
    831 }
    832 
    833 static void
    834 ptprint(tp)
    835     struct process *tp;
    836 {
    837     struct timeval tetime, diff;
    838     static struct timeval ztime;
    839     struct rusage ru;
    840     static struct rusage zru;
    841     struct process *pp = tp;
    842 
    843     ru = zru;
    844     tetime = ztime;
    845     do {
    846 	ruadd(&ru, &pp->p_rusage);
    847 	timersub(&pp->p_etime, &pp->p_btime, &diff);
    848 	if (timercmp(&diff, &tetime, >))
    849 	    tetime = diff;
    850     } while ((pp = pp->p_friends) != tp);
    851     prusage(&zru, &ru, &tetime, &ztime);
    852 }
    853 
    854 /*
    855  * dojobs - print all jobs
    856  */
    857 void
    858 /*ARGSUSED*/
    859 dojobs(v, t)
    860     Char **v;
    861     struct command *t;
    862 {
    863     struct process *pp;
    864     int flag = NUMBER | NAME | REASON;
    865     int     i;
    866 
    867     if (chkstop)
    868 	chkstop = 2;
    869     if (*++v) {
    870 	if (v[1] || !eq(*v, STRml))
    871 	    stderror(ERR_JOBS);
    872 	flag |= FANCY | JOBDIR;
    873     }
    874     for (i = 1; i <= pmaxindex; i++)
    875 	for (pp = proclist.p_next; pp; pp = pp->p_next)
    876 	    if (pp->p_index == i && pp->p_pid == pp->p_jobid) {
    877 		pp->p_flags &= ~PNEEDNOTE;
    878 		if (!(pprint(pp, flag) & (PRUNNING | PSTOPPED)))
    879 		    pflush(pp);
    880 		break;
    881 	    }
    882 }
    883 
    884 /*
    885  * dofg - builtin - put the job into the foreground
    886  */
    887 void
    888 /*ARGSUSED*/
    889 dofg(v, t)
    890     Char **v;
    891     struct command *t;
    892 {
    893     struct process *pp;
    894 
    895     okpcntl();
    896     ++v;
    897     do {
    898 	pp = pfind(*v);
    899 	pstart(pp, 1);
    900 	pjwait(pp);
    901     } while (*v && *++v);
    902 }
    903 
    904 /*
    905  * %... - builtin - put the job into the foreground
    906  */
    907 void
    908 /*ARGSUSED*/
    909 dofg1(v, t)
    910     Char **v;
    911     struct command *t;
    912 {
    913     struct process *pp;
    914 
    915     okpcntl();
    916     pp = pfind(v[0]);
    917     pstart(pp, 1);
    918     pjwait(pp);
    919 }
    920 
    921 /*
    922  * dobg - builtin - put the job into the background
    923  */
    924 void
    925 /*ARGSUSED*/
    926 dobg(v, t)
    927     Char **v;
    928     struct command *t;
    929 {
    930     struct process *pp;
    931 
    932     okpcntl();
    933     ++v;
    934     do {
    935 	pp = pfind(*v);
    936 	pstart(pp, 0);
    937     } while (*v && *++v);
    938 }
    939 
    940 /*
    941  * %... & - builtin - put the job into the background
    942  */
    943 void
    944 /*ARGSUSED*/
    945 dobg1(v, t)
    946     Char **v;
    947     struct command *t;
    948 {
    949     struct process *pp;
    950 
    951     pp = pfind(v[0]);
    952     pstart(pp, 0);
    953 }
    954 
    955 /*
    956  * dostop - builtin - stop the job
    957  */
    958 void
    959 /*ARGSUSED*/
    960 dostop(v, t)
    961     Char **v;
    962     struct command *t;
    963 {
    964     pkill(++v, SIGSTOP);
    965 }
    966 
    967 /*
    968  * dokill - builtin - superset of kill (1)
    969  */
    970 void
    971 /*ARGSUSED*/
    972 dokill(v, t)
    973     Char **v;
    974     struct command *t;
    975 {
    976     int signum = SIGTERM;
    977     char *name;
    978 
    979     v++;
    980     if (v[0] && v[0][0] == '-') {
    981 	if (v[0][1] == 'l') {
    982 	    for (signum = 1; signum < NSIG; signum++) {
    983 		(void) fprintf(cshout, "%s ", sys_signame[signum]);
    984 		if (signum == NSIG / 2)
    985 		    (void) fputc('\n', cshout);
    986 	    }
    987 	    (void) fputc('\n', cshout);
    988 	    return;
    989 	}
    990 	if (Isdigit(v[0][1])) {
    991 	    signum = atoi(short2str(v[0] + 1));
    992 	    if (signum < 0 || signum > NSIG)
    993 		stderror(ERR_NAME | ERR_BADSIG);
    994 	}
    995 	else {
    996 	    name = short2str(&v[0][1]);
    997 	    if (!strncasecmp(name, "sig", 3))
    998 		name += 3;
    999 
   1000 	    for (signum = 1; signum < NSIG; signum++)
   1001 		if (!strcasecmp(sys_signame[signum], name))
   1002 		    break;
   1003 
   1004 	    if (signum == NSIG) {
   1005 		setname(vis_str(&v[0][1]));
   1006 		stderror(ERR_NAME | ERR_UNKSIG);
   1007 	    }
   1008 	}
   1009 	v++;
   1010     }
   1011     pkill(v, signum);
   1012 }
   1013 
   1014 static void
   1015 pkill(v, signum)
   1016     Char  **v;
   1017     int     signum;
   1018 {
   1019     struct process *pp, *np;
   1020     int jobflags = 0;
   1021     int     pid, err1 = 0;
   1022     sigset_t sigset;
   1023     Char   *cp;
   1024 
   1025     sigemptyset(&sigset);
   1026     sigaddset(&sigset, SIGCHLD);
   1027     if (setintr)
   1028 	sigaddset(&sigset, SIGINT);
   1029     sigprocmask(SIG_BLOCK, &sigset, NULL);
   1030     gflag = 0, tglob(v);
   1031     if (gflag) {
   1032 	v = globall(v);
   1033 	if (v == 0)
   1034 	    stderror(ERR_NAME | ERR_NOMATCH);
   1035     }
   1036     else {
   1037 	v = gargv = saveblk(v);
   1038 	trim(v);
   1039     }
   1040 
   1041     while (v && (cp = *v)) {
   1042 	if (*cp == '%') {
   1043 	    np = pp = pfind(cp);
   1044 	    do
   1045 		jobflags |= np->p_flags;
   1046 	    while ((np = np->p_friends) != pp);
   1047 	    switch (signum) {
   1048 
   1049 	    case SIGSTOP:
   1050 	    case SIGTSTP:
   1051 	    case SIGTTIN:
   1052 	    case SIGTTOU:
   1053 		if ((jobflags & PRUNNING) == 0) {
   1054 		    (void) fprintf(csherr, "%s: Already suspended\n",
   1055 				   vis_str(cp));
   1056 		    err1++;
   1057 		    goto cont;
   1058 		}
   1059 		break;
   1060 		/*
   1061 		 * suspend a process, kill -CONT %, then type jobs; the shell
   1062 		 * says it is suspended, but it is running; thanks jaap..
   1063 		 */
   1064 	    case SIGCONT:
   1065 		pstart(pp, 0);
   1066 		goto cont;
   1067 	    }
   1068 	    if (kill(-pp->p_jobid, signum) < 0) {
   1069 		(void) fprintf(csherr, "%s: %s\n", vis_str(cp),
   1070 			       strerror(errno));
   1071 		err1++;
   1072 	    }
   1073 	    if (signum == SIGTERM || signum == SIGHUP)
   1074 		(void) kill(-pp->p_jobid, SIGCONT);
   1075 	}
   1076 	else if (!(Isdigit(*cp) || *cp == '-'))
   1077 	    stderror(ERR_NAME | ERR_JOBARGS);
   1078 	else {
   1079 	    pid = atoi(short2str(cp));
   1080 	    if (kill((pid_t) pid, signum) < 0) {
   1081 		(void) fprintf(csherr, "%d: %s\n", pid, strerror(errno));
   1082 		err1++;
   1083 		goto cont;
   1084 	    }
   1085 	    if (signum == SIGTERM || signum == SIGHUP)
   1086 		(void) kill((pid_t) pid, SIGCONT);
   1087 	}
   1088 cont:
   1089 	v++;
   1090     }
   1091     if (gargv)
   1092 	blkfree(gargv), gargv = 0;
   1093     sigprocmask(SIG_UNBLOCK, &sigset, NULL);
   1094     if (err1)
   1095 	stderror(ERR_SILENT);
   1096 }
   1097 
   1098 /*
   1099  * pstart - start the job in foreground/background
   1100  */
   1101 void
   1102 pstart(pp, foregnd)
   1103     struct process *pp;
   1104     int     foregnd;
   1105 {
   1106     struct process *np;
   1107     sigset_t sigset, osigset;
   1108     long    jobflags = 0;
   1109 
   1110     sigemptyset(&sigset);
   1111     sigaddset(&sigset, SIGCHLD);
   1112     sigprocmask(SIG_BLOCK, &sigset, &osigset);
   1113     np = pp;
   1114     do {
   1115 	jobflags |= np->p_flags;
   1116 	if (np->p_flags & (PRUNNING | PSTOPPED)) {
   1117 	    np->p_flags |= PRUNNING;
   1118 	    np->p_flags &= ~PSTOPPED;
   1119 	    if (foregnd)
   1120 		np->p_flags |= PFOREGND;
   1121 	    else
   1122 		np->p_flags &= ~PFOREGND;
   1123 	}
   1124     } while ((np = np->p_friends) != pp);
   1125     if (!foregnd)
   1126 	pclrcurr(pp);
   1127     (void) pprint(pp, foregnd ? NAME | JOBDIR : NUMBER | NAME | AMPERSAND);
   1128     if (foregnd)
   1129 	(void) tcsetpgrp(FSHTTY, pp->p_jobid);
   1130     if (jobflags & PSTOPPED)
   1131 	(void) kill(-pp->p_jobid, SIGCONT);
   1132     sigprocmask(SIG_SETMASK, &osigset, NULL);
   1133 }
   1134 
   1135 void
   1136 panystop(neednl)
   1137     bool    neednl;
   1138 {
   1139     struct process *pp;
   1140 
   1141     chkstop = 2;
   1142     for (pp = proclist.p_next; pp; pp = pp->p_next)
   1143 	if (pp->p_flags & PSTOPPED)
   1144 	    stderror(ERR_STOPPED, neednl ? "\n" : "");
   1145 }
   1146 
   1147 struct process *
   1148 pfind(cp)
   1149     Char   *cp;
   1150 {
   1151     struct process *pp, *np;
   1152 
   1153     if (cp == 0 || cp[1] == 0 || eq(cp, STRcent2) || eq(cp, STRcentplus)) {
   1154 	if (pcurrent == NULL)
   1155 	    stderror(ERR_NAME | ERR_JOBCUR);
   1156 	return (pcurrent);
   1157     }
   1158     if (eq(cp, STRcentminus) || eq(cp, STRcenthash)) {
   1159 	if (pprevious == NULL)
   1160 	    stderror(ERR_NAME | ERR_JOBPREV);
   1161 	return (pprevious);
   1162     }
   1163     if (Isdigit(cp[1])) {
   1164 	int     idx = atoi(short2str(cp + 1));
   1165 
   1166 	for (pp = proclist.p_next; pp; pp = pp->p_next)
   1167 	    if (pp->p_index == idx && pp->p_pid == pp->p_jobid)
   1168 		return (pp);
   1169 	stderror(ERR_NAME | ERR_NOSUCHJOB);
   1170     }
   1171     np = NULL;
   1172     for (pp = proclist.p_next; pp; pp = pp->p_next)
   1173 	if (pp->p_pid == pp->p_jobid) {
   1174 	    if (cp[1] == '?') {
   1175 		Char *dp;
   1176 
   1177 		for (dp = pp->p_command; *dp; dp++) {
   1178 		    if (*dp != cp[2])
   1179 			continue;
   1180 		    if (prefix(cp + 2, dp))
   1181 			goto match;
   1182 		}
   1183 	    }
   1184 	    else if (prefix(cp + 1, pp->p_command)) {
   1185 	match:
   1186 		if (np)
   1187 		    stderror(ERR_NAME | ERR_AMBIG);
   1188 		np = pp;
   1189 	    }
   1190 	}
   1191     if (np)
   1192 	return (np);
   1193     stderror(ERR_NAME | (cp[1] == '?' ? ERR_JOBPAT : ERR_NOSUCHJOB));
   1194     /* NOTREACHED */
   1195     return (0);
   1196 }
   1197 
   1198 
   1199 /*
   1200  * pgetcurr - find most recent job that is not pp, preferably stopped
   1201  */
   1202 static struct process *
   1203 pgetcurr(pp)
   1204     struct process *pp;
   1205 {
   1206     struct process *np;
   1207     struct process *xp = NULL;
   1208 
   1209     for (np = proclist.p_next; np; np = np->p_next)
   1210 	if (np != pcurrent && np != pp && np->p_pid &&
   1211 	    np->p_pid == np->p_jobid) {
   1212 	    if (np->p_flags & PSTOPPED)
   1213 		return (np);
   1214 	    if (xp == NULL)
   1215 		xp = np;
   1216 	}
   1217     return (xp);
   1218 }
   1219 
   1220 /*
   1221  * donotify - flag the job so as to report termination asynchronously
   1222  */
   1223 void
   1224 /*ARGSUSED*/
   1225 donotify(v, t)
   1226     Char **v;
   1227     struct command *t;
   1228 {
   1229     struct process *pp;
   1230 
   1231     pp = pfind(*++v);
   1232     pp->p_flags |= PNOTIFY;
   1233 }
   1234 
   1235 /*
   1236  * Do the fork and whatever should be done in the child side that
   1237  * should not be done if we are not forking at all (like for simple builtin's)
   1238  * Also do everything that needs any signals fiddled with in the parent side
   1239  *
   1240  * Wanttty tells whether process and/or tty pgrps are to be manipulated:
   1241  *	-1:	leave tty alone; inherit pgrp from parent
   1242  *	 0:	already have tty; manipulate process pgrps only
   1243  *	 1:	want to claim tty; manipulate process and tty pgrps
   1244  * It is usually just the value of tpgrp.
   1245  */
   1246 
   1247 int
   1248 pfork(t, wanttty)
   1249     struct command *t;		/* command we are forking for */
   1250     int     wanttty;
   1251 {
   1252     int pid;
   1253     bool    ignint = 0;
   1254     int     pgrp;
   1255     sigset_t sigset, osigset;
   1256 
   1257     /*
   1258      * A child will be uninterruptible only under very special conditions.
   1259      * Remember that the semantics of '&' is implemented by disconnecting the
   1260      * process from the tty so signals do not need to ignored just for '&'.
   1261      * Thus signals are set to default action for children unless: we have had
   1262      * an "onintr -" (then specifically ignored) we are not playing with
   1263      * signals (inherit action)
   1264      */
   1265     if (setintr)
   1266 	ignint = (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT))
   1267 	    || (gointr && eq(gointr, STRminus));
   1268     /*
   1269      * Check for maximum nesting of 16 processes to avoid Forking loops
   1270      */
   1271     if (child == 16)
   1272 	stderror(ERR_NESTING, 16);
   1273     /*
   1274      * Hold SIGCHLD until we have the process installed in our table.
   1275      */
   1276     sigemptyset(&sigset);
   1277     sigaddset(&sigset, SIGCHLD);
   1278     sigprocmask(SIG_BLOCK, &sigset, &osigset);
   1279     while ((pid = fork()) < 0)
   1280 	if (setintr == 0)
   1281 	    (void) sleep(FORKSLEEP);
   1282 	else {
   1283 	    sigprocmask(SIG_SETMASK, &osigset, NULL);
   1284 	    stderror(ERR_NOPROC);
   1285 	}
   1286     if (pid == 0) {
   1287 	settimes();
   1288 	pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
   1289 	pflushall();
   1290 	pcurrjob = NULL;
   1291 	child++;
   1292 	if (setintr) {
   1293 	    setintr = 0;	/* until I think otherwise */
   1294 	    /*
   1295 	     * Children just get blown away on SIGINT, SIGQUIT unless "onintr
   1296 	     * -" seen.
   1297 	     */
   1298 	    (void) signal(SIGINT, ignint ? SIG_IGN : SIG_DFL);
   1299 	    (void) signal(SIGQUIT, ignint ? SIG_IGN : SIG_DFL);
   1300 	    if (wanttty >= 0) {
   1301 		/* make stoppable */
   1302 		(void) signal(SIGTSTP, SIG_DFL);
   1303 		(void) signal(SIGTTIN, SIG_DFL);
   1304 		(void) signal(SIGTTOU, SIG_DFL);
   1305 	    }
   1306 	    (void) signal(SIGTERM, parterm);
   1307 	}
   1308 	else if (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT)) {
   1309 	    (void) signal(SIGINT, SIG_IGN);
   1310 	    (void) signal(SIGQUIT, SIG_IGN);
   1311 	}
   1312 	pgetty(wanttty, pgrp);
   1313 	/*
   1314 	 * Nohup and nice apply only to NODE_COMMAND's but it would be nice
   1315 	 * (?!?) if you could say "nohup (foo;bar)" Then the parser would have
   1316 	 * to know about nice/nohup/time
   1317 	 */
   1318 	if (t->t_dflg & F_NOHUP)
   1319 	    (void) signal(SIGHUP, SIG_IGN);
   1320 	if (t->t_dflg & F_NICE)
   1321 	    (void) setpriority(PRIO_PROCESS, 0, t->t_nice);
   1322     }
   1323     else {
   1324 	if (wanttty >= 0)
   1325 	    (void) setpgid(pid, pcurrjob ? pcurrjob->p_jobid : pid);
   1326 	palloc(pid, t);
   1327 	sigprocmask(SIG_SETMASK, &osigset, NULL);
   1328     }
   1329 
   1330     return (pid);
   1331 }
   1332 
   1333 static void
   1334 okpcntl()
   1335 {
   1336     if (tpgrp == -1)
   1337 	stderror(ERR_JOBCONTROL);
   1338     if (tpgrp == 0)
   1339 	stderror(ERR_JOBCTRLSUB);
   1340 }
   1341 
   1342 /*
   1343  * if we don't have vfork(), things can still go in the wrong order
   1344  * resulting in the famous 'Stopped (tty output)'. But some systems
   1345  * don't permit the setpgid() call, (these are more recent secure
   1346  * systems such as ibm's aix). Then we'd rather print an error message
   1347  * than hang the shell!
   1348  * I am open to suggestions how to fix that.
   1349  */
   1350 void
   1351 pgetty(wanttty, pgrp)
   1352     int     wanttty, pgrp;
   1353 {
   1354     sigset_t sigset, osigset;
   1355 
   1356     /*
   1357      * christos: I am blocking the tty signals till I've set things
   1358      * correctly....
   1359      */
   1360     if (wanttty > 0) {
   1361 	sigemptyset(&sigset);
   1362 	sigaddset(&sigset, SIGTSTP);
   1363 	sigaddset(&sigset, SIGTTIN);
   1364 	sigaddset(&sigset, SIGTTOU);
   1365 	sigprocmask(SIG_BLOCK, &sigset, &osigset);
   1366     }
   1367     /*
   1368      * From: Michael Schroeder <mlschroe (at) immd4.informatik.uni-erlangen.de>
   1369      * Don't check for tpgrp >= 0 so even non-interactive shells give
   1370      * background jobs process groups Same for the comparison in the other part
   1371      * of the #ifdef
   1372      */
   1373     if (wanttty >= 0)
   1374 	if (setpgid(0, pgrp) == -1) {
   1375 	    (void) fprintf(csherr, "csh: setpgid error.\n");
   1376 	    xexit(0);
   1377 	}
   1378 
   1379     if (wanttty > 0) {
   1380 	(void) tcsetpgrp(FSHTTY, pgrp);
   1381 	sigprocmask(SIG_SETMASK, &osigset, NULL);
   1382     }
   1383 
   1384     if (tpgrp > 0)
   1385 	tpgrp = 0;		/* gave tty away */
   1386 }
   1387