bin/csh/proc.c

/*-
 * Copyright (c) 1980, 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
static char sccsid[] = "@(#)proc.c	5.24 (Berkeley) 07/20/91";
#endif /* not lint */

#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#if __STDC__
# include <stdarg.h>
#else
# include <varargs.h>
#endif

#include "csh.h"
#include "dir.h"
#include "proc.h"
#include "extern.h"

#define BIGINDEX	9	/* largest desirable job index */

static struct rusage zru;

static void	 pflushall __P((void));
static void	 pflush __P((struct process *));
static void	 pclrcurr __P((struct process *));
static void	 padd __P((struct command *));
static int	 pprint __P((struct process *, int));
static void	 ptprint __P((struct process *));
static void	 pads __P((Char *));
static void	 pkill __P((Char **v, int));
static struct	process
		*pgetcurr __P((struct process *));
static void	 okpcntl __P((void));

/*
 * pchild - called at interrupt level by the SIGCHLD signal
 *	indicating that at least one child has terminated or stopped
 *	thus at least one wait system call will definitely return a
 *	childs status.  Top level routines (like pwait) must be sure
 *	to mask interrupts when playing with the proclist data structures!
 */
/* ARGUSED */
void
pchild(notused)
	int notused;
{
    register struct process *pp;
    register struct process *fp;
    register int pid;
    extern int insource;
    union wait w;
    int     jobflags;
    struct rusage ru;

loop:
    errno = 0;			/* reset, just in case */
    pid = wait3(&w.w_status,
       (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG), &ru);

    if (pid <= 0) {
	if (errno == EINTR) {
	    errno = 0;
	    goto loop;
	}
	pnoprocesses = pid == -1;
	return;
    }
    for (pp = proclist.p_next; pp != NULL; pp = pp->p_next)
	if (pid == pp->p_pid)
	    goto found;
    goto loop;
found:
    if (pid == atoi(short2str(value(STRchild))))
	unsetv(STRchild);
    pp->p_flags &= ~(PRUNNING | PSTOPPED | PREPORTED);
    if (WIFSTOPPED(w)) {
	pp->p_flags |= PSTOPPED;
	pp->p_reason = w.w_stopsig;
    }
    else {
	if (pp->p_flags & (PTIME | PPTIME) || adrof(STRtime))
	    (void) gettimeofday(&pp->p_etime, NULL);

	pp->p_rusage = ru;
	if (WIFSIGNALED(w)) {
	    if (w.w_termsig == SIGINT)
		pp->p_flags |= PINTERRUPTED;
	    else
		pp->p_flags |= PSIGNALED;
	    if (w.w_coredump)
		pp->p_flags |= PDUMPED;
	    pp->p_reason = w.w_termsig;
	}
	else {
	    pp->p_reason = w.w_retcode;
	    if (pp->p_reason != 0)
		pp->p_flags |= PAEXITED;
	    else
		pp->p_flags |= PNEXITED;
	}
    }
    jobflags = 0;
    fp = pp;
    do {
	if ((fp->p_flags & (PPTIME | PRUNNING | PSTOPPED)) == 0 &&
	    !child && adrof(STRtime) &&
	    fp->p_rusage.ru_utime.tv_sec + fp->p_rusage.ru_stime.tv_sec
	    >= atoi(short2str(value(STRtime))))
	    fp->p_flags |= PTIME;
	jobflags |= fp->p_flags;
    } while ((fp = fp->p_friends) != pp);
    pp->p_flags &= ~PFOREGND;
    if (pp == pp->p_friends && (pp->p_flags & PPTIME)) {
	pp->p_flags &= ~PPTIME;
	pp->p_flags |= PTIME;
    }
    if ((jobflags & (PRUNNING | PREPORTED)) == 0) {
	fp = pp;
	do {
	    if (fp->p_flags & PSTOPPED)
		fp->p_flags |= PREPORTED;
	} while ((fp = fp->p_friends) != pp);
	while (fp->p_pid != fp->p_jobid)
	    fp = fp->p_friends;
	if (jobflags & PSTOPPED) {
	    if (pcurrent && pcurrent != fp)
		pprevious = pcurrent;
	    pcurrent = fp;
	}
	else
	    pclrcurr(fp);
	if (jobflags & PFOREGND) {
	    if (jobflags & (PSIGNALED | PSTOPPED | PPTIME) ||
#ifdef IIASA
		jobflags & PAEXITED ||
#endif
		!eq(dcwd->di_name, fp->p_cwd->di_name)) {
		;		/* print in pjwait */
	    }
	    /* PWP: print a newline after ^C */
	    else if (jobflags & PINTERRUPTED) {
		(void) fputc('\r' | QUOTE, cshout);
		(void) fputc('\n', cshout);
	    }
	}
	else {
	    if (jobflags & PNOTIFY || adrof(STRnotify)) {
		(void) fputc('\r' | QUOTE, cshout);
		(void) fputc('\n', cshout);
		(void) pprint(pp, NUMBER | NAME | REASON);
		if ((jobflags & PSTOPPED) == 0)
		    pflush(pp);
	    }
	    else {
		fp->p_flags |= PNEEDNOTE;
		neednote++;
	    }
	}
    }
    goto loop;
}

void
pnote()
{
    register struct process *pp;
    int     flags;
    sigset_t omask;

    neednote = 0;
    for (pp = proclist.p_next; pp != NULL; pp = pp->p_next) {
	if (pp->p_flags & PNEEDNOTE) {
	    omask = sigblock(sigmask(SIGCHLD));
	    pp->p_flags &= ~PNEEDNOTE;
	    flags = pprint(pp, NUMBER | NAME | REASON);
	    if ((flags & (PRUNNING | PSTOPPED)) == 0)
		pflush(pp);
	    (void) sigsetmask(omask);
	}
    }
}

/*
 * pwait - wait for current job to terminate, maintaining integrity
 *	of current and previous job indicators.
 */
void
pwait()
{
    register struct process *fp, *pp;
    sigset_t omask;

    /*
     * Here's where dead procs get flushed.
     */
    omask = sigblock(sigmask(SIGCHLD));
    for (pp = (fp = &proclist)->p_next; pp != NULL; pp = (fp = pp)->p_next)
	if (pp->p_pid == 0) {
	    fp->p_next = pp->p_next;
	    xfree((ptr_t) pp->p_command);
	    if (pp->p_cwd && --pp->p_cwd->di_count == 0)
		if (pp->p_cwd->di_next == 0)
		    dfree(pp->p_cwd);
	    xfree((ptr_t) pp);
	    pp = fp;
	}
    (void) sigsetmask(omask);
    pjwait(pcurrjob);
}


/*
 * pjwait - wait for a job to finish or become stopped
 *	It is assumed to be in the foreground state (PFOREGND)
 */
void
pjwait(pp)
    register struct process *pp;
{
    register struct process *fp;
    int     jobflags, reason;
    sigset_t omask;

    while (pp->p_pid != pp->p_jobid)
	pp = pp->p_friends;
    fp = pp;

    do {
	if ((fp->p_flags & (PFOREGND | PRUNNING)) == PRUNNING)
	    (void) fprintf(csherr, "BUG: waiting for background job!\n");
    } while ((fp = fp->p_friends) != pp);
    /*
     * Now keep pausing as long as we are not interrupted (SIGINT), and the
     * target process, or any of its friends, are running
     */
    fp = pp;
    omask = sigblock(sigmask(SIGCHLD));
    for (;;) {
	(void) sigblock(sigmask(SIGCHLD));
	jobflags = 0;
	do
	    jobflags |= fp->p_flags;
	while ((fp = (fp->p_friends)) != pp);
	if ((jobflags & PRUNNING) == 0)
	    break;
#ifdef JOBDEBUG
	(void) fprintf(csherr, "starting to sigpause for  SIGCHLD on %d\n",
		       fp->p_pid);
#endif				/* JOBDEBUG */
	(void) sigpause(omask & ~sigmask(SIGCHLD));
    }
    (void) sigsetmask(omask);
    if (tpgrp > 0)		/* get tty back */
	(void) tcsetpgrp(FSHTTY, tpgrp);
    if ((jobflags & (PSIGNALED | PSTOPPED | PTIME)) ||
	!eq(dcwd->di_name, fp->p_cwd->di_name)) {
	if (jobflags & PSTOPPED) {
	    (void) fputc('\n', cshout);
	    if (adrof(STRlistjobs)) {
		Char   *jobcommand[3];

		jobcommand[0] = STRjobs;
		if (eq(value(STRlistjobs), STRlong))
		    jobcommand[1] = STRml;
		else
		    jobcommand[1] = NULL;
		jobcommand[2] = NULL;

		dojobs(jobcommand, NULL);
		(void) pprint(pp, SHELLDIR);
	    }
	    else
		(void) pprint(pp, AREASON | SHELLDIR);
	}
	else
	    (void) pprint(pp, AREASON | SHELLDIR);
    }
    if ((jobflags & (PINTERRUPTED | PSTOPPED)) && setintr &&
	(!gointr || !eq(gointr, STRminus))) {
	if ((jobflags & PSTOPPED) == 0)
	    pflush(pp);
	pintr1(0);
	/* NOTREACHED */
    }
    reason = 0;
    fp = pp;
    do {
	if (fp->p_reason)
	    reason = fp->p_flags & (PSIGNALED | PINTERRUPTED) ?
		fp->p_reason | META : fp->p_reason;
    } while ((fp = fp->p_friends) != pp);
    if ((reason != 0) && (adrof(STRprintexitvalue))) {
	(void) fprintf(cshout, "Exit %d\n", reason);
    }
    set(STRstatus, putn(reason));
    if (reason && exiterr)
	exitstat();
    pflush(pp);
}

/*
 * dowait - wait for all processes to finish
 */
void
/*ARGSUSED*/
dowait(v, t)
    Char **v;
    struct command *t;
{
    register struct process *pp;
    sigset_t omask;

    pjobs++;
    omask = sigblock(sigmask(SIGCHLD));
loop:
    for (pp = proclist.p_next; pp; pp = pp->p_next)
	if (pp->p_pid &&	/* pp->p_pid == pp->p_jobid && */
	    pp->p_flags & PRUNNING) {
	    (void) sigpause((sigset_t) 0);
	    goto loop;
	}
    (void) sigsetmask(omask);
    pjobs = 0;
}

/*
 * pflushall - flush all jobs from list (e.g. at fork())
 */
static void
pflushall()
{
    register struct process *pp;

    for (pp = proclist.p_next; pp != NULL; pp = pp->p_next)
	if (pp->p_pid)
	    pflush(pp);
}

/*
 * pflush - flag all process structures in the same job as the
 *	the argument process for deletion.  The actual free of the
 *	space is not done here since pflush is called at interrupt level.
 */
static void
pflush(pp)
    register struct process *pp;
{
    register struct process *np;
    register int idx;

    if (pp->p_pid == 0) {
	(void) fprintf(csherr, "BUG: process flushed twice");
	return;
    }
    while (pp->p_pid != pp->p_jobid)
	pp = pp->p_friends;
    pclrcurr(pp);
    if (pp == pcurrjob)
	pcurrjob = 0;
    idx = pp->p_index;
    np = pp;
    do {
	np->p_index = np->p_pid = 0;
	np->p_flags &= ~PNEEDNOTE;
    } while ((np = np->p_friends) != pp);
    if (idx == pmaxindex) {
	for (np = proclist.p_next, idx = 0; np; np = np->p_next)
	    if (np->p_index > idx)
		idx = np->p_index;
	pmaxindex = idx;
    }
}

/*
 * pclrcurr - make sure the given job is not the current or previous job;
 *	pp MUST be the job leader
 */
static void
pclrcurr(pp)
    register struct process *pp;
{

    if (pp == pcurrent)
	if (pprevious != NULL) {
	    pcurrent = pprevious;
	    pprevious = pgetcurr(pp);
	}
	else {
	    pcurrent = pgetcurr(pp);
	    pprevious = pgetcurr(pp);
	}
    else if (pp == pprevious)
	pprevious = pgetcurr(pp);
}

/* +4 here is 1 for '\0', 1 ea for << >& >> */
static Char command[PMAXLEN + 4];
static int cmdlen;
static Char *cmdp;

/*
 * palloc - allocate a process structure and fill it up.
 *	an important assumption is made that the process is running.
 */
void
palloc(pid, t)
    int     pid;
    register struct command *t;
{
    register struct process *pp;
    int     i;

    pp = (struct process *) xcalloc(1, (size_t) sizeof(struct process));
    pp->p_pid = pid;
    pp->p_flags = t->t_dflg & F_AMPERSAND ? PRUNNING : PRUNNING | PFOREGND;
    if (t->t_dflg & F_TIME)
	pp->p_flags |= PPTIME;
    cmdp = command;
    cmdlen = 0;
    padd(t);
    *cmdp++ = 0;
    if (t->t_dflg & F_PIPEOUT) {
	pp->p_flags |= PPOU;
	if (t->t_dflg & F_STDERR)
	    pp->p_flags |= PERR;
    }
    pp->p_command = Strsave(command);
    if (pcurrjob) {
	struct process *fp;

	/* careful here with interrupt level */
	pp->p_cwd = 0;
	pp->p_index = pcurrjob->p_index;
	pp->p_friends = pcurrjob;
	pp->p_jobid = pcurrjob->p_pid;
	for (fp = pcurrjob; fp->p_friends != pcurrjob; fp = fp->p_friends);
	fp->p_friends = pp;
    }
    else {
	pcurrjob = pp;
	pp->p_jobid = pid;
	pp->p_friends = pp;
	pp->p_cwd = dcwd;
	dcwd->di_count++;
	if (pmaxindex < BIGINDEX)
	    pp->p_index = ++pmaxindex;
	else {
	    struct process *np;

	    for (i = 1;; i++) {
		for (np = proclist.p_next; np; np = np->p_next)
		    if (np->p_index == i)
			goto tryagain;
		pp->p_index = i;
		if (i > pmaxindex)
		    pmaxindex = i;
		break;
	tryagain:;
	    }
	}
	if (pcurrent == NULL)
	    pcurrent = pp;
	else if (pprevious == NULL)
	    pprevious = pp;
    }
    pp->p_next = proclist.p_next;
    proclist.p_next = pp;
    (void) gettimeofday(&pp->p_btime, NULL);
}

static void
padd(t)
    register struct command *t;
{
    Char  **argp;

    if (t == 0)
	return;
    switch (t->t_dtyp) {

    case NODE_PAREN:
	pads(STRLparensp);
	padd(t->t_dspr);
	pads(STRspRparen);
	break;

    case NODE_COMMAND:
	for (argp = t->t_dcom; *argp; argp++) {
	    pads(*argp);
	    if (argp[1])
		pads(STRspace);
	}
	break;

    case NODE_OR:
    case NODE_AND:
    case NODE_PIPE:
    case NODE_LIST:
	padd(t->t_dcar);
	switch (t->t_dtyp) {
	case NODE_OR:
	    pads(STRspor2sp);
	    break;
	case NODE_AND:
	    pads(STRspand2sp);
	    break;
	case NODE_PIPE:
	    pads(STRsporsp);
	    break;
	case NODE_LIST:
	    pads(STRsemisp);
	    break;
	}
	padd(t->t_dcdr);
	return;
    }
    if ((t->t_dflg & F_PIPEIN) == 0 && t->t_dlef) {
	pads((t->t_dflg & F_READ) ? STRspLarrow2sp : STRspLarrowsp);
	pads(t->t_dlef);
    }
    if ((t->t_dflg & F_PIPEOUT) == 0 && t->t_drit) {
	pads((t->t_dflg & F_APPEND) ? STRspRarrow2 : STRspRarrow);
	if (t->t_dflg & F_STDERR)
	    pads(STRand);
	pads(STRspace);
	pads(t->t_drit);
    }
}

static void
pads(cp)
    Char   *cp;
{
    register int i;

    /*
     * Avoid the Quoted Space alias hack! Reported by:
     * sam@john-bigboote.ICS.UCI.EDU (Sam Horrocks)
     */
    if (cp[0] == STRQNULL[0])
	cp++;

    i = Strlen(cp);

    if (cmdlen >= PMAXLEN)
	return;
    if (cmdlen + i >= PMAXLEN) {
	(void) Strcpy(cmdp, STRsp3dots);
	cmdlen = PMAXLEN;
	cmdp += 4;
	return;
    }
    (void) Strcpy(cmdp, cp);
    cmdp += i;
    cmdlen += i;
}

/*
 * psavejob - temporarily save the current job on a one level stack
 *	so another job can be created.  Used for { } in exp6
 *	and `` in globbing.
 */
void
psavejob()
{

    pholdjob = pcurrjob;
    pcurrjob = NULL;
}

/*
 * prestjob - opposite of psavejob.  This may be missed if we are interrupted
 *	somewhere, but pendjob cleans up anyway.
 */
void
prestjob()
{

    pcurrjob = pholdjob;
    pholdjob = NULL;
}

/*
 * pendjob - indicate that a job (set of commands) has been completed
 *	or is about to begin.
 */
void
pendjob()
{
    register struct process *pp, *tp;

    if (pcurrjob && (pcurrjob->p_flags & (PFOREGND | PSTOPPED)) == 0) {
	pp = pcurrjob;
	while (pp->p_pid != pp->p_jobid)
	    pp = pp->p_friends;
	(void) fprintf(cshout, "[%d]", pp->p_index);
	tp = pp;
	do {
	    (void) fprintf(cshout, " %d", pp->p_pid);
	    pp = pp->p_friends;
	} while (pp != tp);
	(void) fputc('\n', cshout);
    }
    pholdjob = pcurrjob = 0;
}

/*
 * pprint - print a job
 */
static int
pprint(pp, flag)
    register struct process *pp;
    bool    flag;
{
    register status, reason;
    struct process *tp;
    int     jobflags, pstatus;
    bool hadnl = 1;	/* did we just have a newline */
    char   *format;

    (void) fpurge(cshout);

    while (pp->p_pid != pp->p_jobid)
	pp = pp->p_friends;
    if (pp == pp->p_friends && (pp->p_flags & PPTIME)) {
	pp->p_flags &= ~PPTIME;
	pp->p_flags |= PTIME;
    }
    tp = pp;
    status = reason = -1;
    jobflags = 0;
    do {
	jobflags |= pp->p_flags;
	pstatus = pp->p_flags & PALLSTATES;
	if (tp != pp && !hadnl && !(flag & FANCY) &&
	    ((pstatus == status && pp->p_reason == reason) ||
	     !(flag & REASON))) {
	    (void) fputc(' ', cshout);
	    hadnl = 0;
	}
	else {
	    if (tp != pp && !hadnl) {
		(void) fputc('\n', cshout);
		hadnl = 1;
	    }
	    if (flag & NUMBER) {
		if (pp == tp)
		    (void) fprintf(cshout, "[%d]%s %c ", pp->p_index,
			    pp->p_index < 10 ? " " : "",
			    pp == pcurrent ? '+' :
			    (pp == pprevious ? '-' : ' '));
		else
		    (void) fprintf(cshout, "       ");
		hadnl = 0;
	    }
	    if (flag & FANCY) {
		(void) fprintf(cshout, "%5d ", pp->p_pid);
		hadnl = 0;
	    }
	    if (flag & (REASON | AREASON)) {
		if (flag & NAME)
		    format = "%-23s";
		else
		    format = "%s";
		if (pstatus == status)
		    if (pp->p_reason == reason) {
			(void) fprintf(cshout, format, "");
			hadnl = 0;
			goto prcomd;
		    }
		    else
			reason = pp->p_reason;
		else {
		    status = pstatus;
		    reason = pp->p_reason;
		}
		switch (status) {

		case PRUNNING:
		    (void) fprintf(cshout, format, "Running ");
		    hadnl = 0;
		    break;

		case PINTERRUPTED:
		case PSTOPPED:
		case PSIGNALED:
                    /*
                     * tell what happened to the background job
                     * From: Michael Schroeder
                     * <mlschroe@immd4.informatik.uni-erlangen.de>
                     */
                    if ((flag & REASON)
                        || ((flag & AREASON)
                            && reason != SIGINT
                            && (reason != SIGPIPE
                                || (pp->p_flags & PPOU) == 0))) {
			(void) fprintf(cshout, format,
				       mesg[pp->p_reason].pname);
			hadnl = 0;
		    }
		    break;

		case PNEXITED:
		case PAEXITED:
		    if (flag & REASON) {
			if (pp->p_reason)
			    (void) fprintf(cshout, "Exit %-18d", pp->p_reason);
			else
			    (void) fprintf(cshout, format, "Done");
			hadnl = 0;
		    }
		    break;

		default:
		    (void) fprintf(csherr, "BUG: status=%-9o", status);
		}
	    }
	}
prcomd:
	if (flag & NAME) {
	    (void) fprintf(cshout, "%s", short2str(pp->p_command));
	    if (pp->p_flags & PPOU)
		(void) fprintf(cshout, " |");
	    if (pp->p_flags & PERR)
		(void) fputc('&', cshout);
	    hadnl = 0;
	}
	if (flag & (REASON | AREASON) && pp->p_flags & PDUMPED) {
	    (void) fprintf(cshout, " (core dumped)");
	    hadnl = 0;
	}
	if (tp == pp->p_friends) {
	    if (flag & AMPERSAND) {
		(void) fprintf(cshout, " &");
		hadnl = 0;
	    }
	    if (flag & JOBDIR &&
		!eq(tp->p_cwd->di_name, dcwd->di_name)) {
		(void) fprintf(cshout, " (wd: ");
		dtildepr(value(STRhome), tp->p_cwd->di_name);
		(void) fputc(')', cshout);
		hadnl = 0;
	    }
	}
	if (pp->p_flags & PPTIME && !(status & (PSTOPPED | PRUNNING))) {
	    if (!hadnl)
		(void) fprintf(cshout, "\n\t");
	    prusage(&zru, &pp->p_rusage, &pp->p_etime,
		    &pp->p_btime);
	    hadnl = 1;
	}
	if (tp == pp->p_friends) {
	    if (!hadnl) {
		(void) fputc('\n', cshout);
		hadnl = 1;
	    }
	    if (flag & SHELLDIR && !eq(tp->p_cwd->di_name, dcwd->di_name)) {
		(void) fprintf(cshout, "(wd now: ");
		dtildepr(value(STRhome), dcwd->di_name);
		(void) fprintf(cshout, ")\n");
		hadnl = 1;
	    }
	}
    } while ((pp = pp->p_friends) != tp);
    if (jobflags & PTIME && (jobflags & (PSTOPPED | PRUNNING)) == 0) {
	if (jobflags & NUMBER)
	    (void) fprintf(cshout, "       ");
	ptprint(tp);
	hadnl = 1;
    }
    (void) fflush(cshout);
    return (jobflags);
}

static void
ptprint(tp)
    register struct process *tp;
{
    struct timeval tetime, diff;
    static struct timeval ztime;
    struct rusage ru;
    static struct rusage zru;
    register struct process *pp = tp;

    ru = zru;
    tetime = ztime;
    do {
	ruadd(&ru, &pp->p_rusage);
	tvsub(&diff, &pp->p_etime, &pp->p_btime);
	if (timercmp(&diff, &tetime, >))
	    tetime = diff;
    } while ((pp = pp->p_friends) != tp);
    prusage(&zru, &ru, &tetime, &ztime);
}

/*
 * dojobs - print all jobs
 */
void
/*ARGSUSED*/
dojobs(v, t)
    Char **v;
    struct command *t;
{
    register struct process *pp;
    register int flag = NUMBER | NAME | REASON;
    int     i;

    if (chkstop)
	chkstop = 2;
    if (*++v) {
	if (v[1] || !eq(*v, STRml))
	    stderror(ERR_JOBS);
	flag |= FANCY | JOBDIR;
    }
    for (i = 1; i <= pmaxindex; i++)
	for (pp = proclist.p_next; pp; pp = pp->p_next)
	    if (pp->p_index == i && pp->p_pid == pp->p_jobid) {
		pp->p_flags &= ~PNEEDNOTE;
		if (!(pprint(pp, flag) & (PRUNNING | PSTOPPED)))
		    pflush(pp);
		break;
	    }
}

/*
 * dofg - builtin - put the job into the foreground
 */
void
/*ARGSUSED*/
dofg(v, t)
    Char **v;
    struct command *t;
{
    register struct process *pp;

    okpcntl();
    ++v;
    do {
	pp = pfind(*v);
	pstart(pp, 1);
	pjwait(pp);
    } while (*v && *++v);
}

/*
 * %... - builtin - put the job into the foreground
 */
void
/*ARGSUSED*/
dofg1(v, t)
    Char **v;
    struct command *t;
{
    register struct process *pp;

    okpcntl();
    pp = pfind(v[0]);
    pstart(pp, 1);
    pjwait(pp);
}

/*
 * dobg - builtin - put the job into the background
 */
void
/*ARGSUSED*/
dobg(v, t)
    Char **v;
    struct command *t;
{
    register struct process *pp;

    okpcntl();
    ++v;
    do {
	pp = pfind(*v);
	pstart(pp, 0);
    } while (*v && *++v);
}

/*
 * %... & - builtin - put the job into the background
 */
void
/*ARGSUSED*/
dobg1(v, t)
    Char **v;
    struct command *t;
{
    register struct process *pp;

    pp = pfind(v[0]);
    pstart(pp, 0);
}

/*
 * dostop - builtin - stop the job
 */
void
/*ARGSUSED*/
dostop(v, t)
    Char **v;
    struct command *t;
{
    pkill(++v, SIGSTOP);
}

/*
 * dokill - builtin - superset of kill (1)
 */
void
/*ARGSUSED*/
dokill(v, t)
    Char **v;
    struct command *t;
{
    register int signum, len = 0;
    register char *name;

    v++;
    if (v[0] && v[0][0] == '-') {
	if (v[0][1] == 'l') {
	    for (signum = 1; signum <= NSIG; signum++) {
		if ((name = mesg[signum].iname) != NULL) {
		    len += strlen(name) + 1;
		    if (len >= 80 - 1) {
			(void) fputc('\n', cshout);
			len = strlen(name) + 1;
		    }
		    (void) fprintf(cshout, "%s ", name);
		}
	    }
	    (void) fputc('\n', cshout);
	    return;
	}
	if (Isdigit(v[0][1])) {
	    signum = atoi(short2str(v[0] + 1));
	    if (signum < 0 || signum > NSIG)
		stderror(ERR_NAME | ERR_BADSIG);
	}
	else {
	    for (signum = 1; signum <= NSIG; signum++)
		if (mesg[signum].iname &&
		    eq(&v[0][1], str2short(mesg[signum].iname)))
		    goto gotsig;
	    setname(short2str(&v[0][1]));
	    stderror(ERR_NAME | ERR_UNKSIG);
	}
gotsig:
	v++;
    }
    else
	signum = SIGTERM;
    pkill(v, signum);
}

static void
pkill(v, signum)
    Char  **v;
    int     signum;
{
    register struct process *pp, *np;
    register int jobflags = 0;
    int     pid, err1 = 0;
    sigset_t omask;
    Char   *cp;

    omask = sigmask(SIGCHLD);
    if (setintr)
	omask |= sigmask(SIGINT);
    omask = sigblock(omask) & ~omask;
    gflag = 0, tglob(v);
    if (gflag) {
	v = globall(v);
	if (v == 0)
	    stderror(ERR_NAME | ERR_NOMATCH);
    }
    else {
	v = gargv = saveblk(v);
	trim(v);
    }

    while (v && (cp = *v)) {
	if (*cp == '%') {
	    np = pp = pfind(cp);
	    do
		jobflags |= np->p_flags;
	    while ((np = np->p_friends) != pp);
	    switch (signum) {

	    case SIGSTOP:
	    case SIGTSTP:
	    case SIGTTIN:
	    case SIGTTOU:
		if ((jobflags & PRUNNING) == 0) {
		    (void) fprintf(csherr, "%s: Already suspended\n",
				   short2str(cp));
		    err1++;
		    goto cont;
		}
		break;
		/*
		 * suspend a process, kill -CONT %, then type jobs; the shell
		 * says it is suspended, but it is running; thanks jaap..
		 */
	    case SIGCONT:
		pstart(pp, 0);
		goto cont;
	    }
	    if (killpg((pid_t) pp->p_jobid, signum) < 0) {
		(void) fprintf(csherr, "%s: %s\n", short2str(cp),
			       strerror(errno));
		err1++;
	    }
	    if (signum == SIGTERM || signum == SIGHUP)
		(void) killpg((pid_t) pp->p_jobid, SIGCONT);
	}
	else if (!(Isdigit(*cp) || *cp == '-'))
	    stderror(ERR_NAME | ERR_JOBARGS);
	else {
	    pid = atoi(short2str(cp));
	    if (kill((pid_t) pid, signum) < 0) {
		(void) fprintf(csherr, "%d: %s\n", pid, strerror(errno));
		err1++;
		goto cont;
	    }
	    if (signum == SIGTERM || signum == SIGHUP)
		(void) kill((pid_t) pid, SIGCONT);
	}
cont:
	v++;
    }
    if (gargv)
	blkfree(gargv), gargv = 0;
    (void) sigsetmask(omask);
    if (err1)
	stderror(ERR_SILENT);
}

/*
 * pstart - start the job in foreground/background
 */
void
pstart(pp, foregnd)
    register struct process *pp;
    int     foregnd;
{
    register struct process *np;
    sigset_t omask;
    long    jobflags = 0;

    omask = sigblock(sigmask(SIGCHLD));
    np = pp;
    do {
	jobflags |= np->p_flags;
	if (np->p_flags & (PRUNNING | PSTOPPED)) {
	    np->p_flags |= PRUNNING;
	    np->p_flags &= ~PSTOPPED;
	    if (foregnd)
		np->p_flags |= PFOREGND;
	    else
		np->p_flags &= ~PFOREGND;
	}
    } while ((np = np->p_friends) != pp);
    if (!foregnd)
	pclrcurr(pp);
    (void) pprint(pp, foregnd ? NAME | JOBDIR : NUMBER | NAME | AMPERSAND);
    if (foregnd)
	(void) tcsetpgrp(FSHTTY, pp->p_jobid);
    if (jobflags & PSTOPPED)
	(void) killpg((pid_t) pp->p_jobid, SIGCONT);
    (void) sigsetmask(omask);
}

void
panystop(neednl)
    bool    neednl;
{
    register struct process *pp;

    chkstop = 2;
    for (pp = proclist.p_next; pp; pp = pp->p_next)
	if (pp->p_flags & PSTOPPED)
	    stderror(ERR_STOPPED, neednl ? "\n" : "");
}

struct process *
pfind(cp)
    Char   *cp;
{
    register struct process *pp, *np;

    if (cp == 0 || cp[1] == 0 || eq(cp, STRcent2) || eq(cp, STRcentplus)) {
	if (pcurrent == NULL)
	    stderror(ERR_NAME | ERR_JOBCUR);
	return (pcurrent);
    }
    if (eq(cp, STRcentminus) || eq(cp, STRcenthash)) {
	if (pprevious == NULL)
	    stderror(ERR_NAME | ERR_JOBPREV);
	return (pprevious);
    }
    if (Isdigit(cp[1])) {
	int     idx = atoi(short2str(cp + 1));

	for (pp = proclist.p_next; pp; pp = pp->p_next)
	    if (pp->p_index == idx && pp->p_pid == pp->p_jobid)
		return (pp);
	stderror(ERR_NAME | ERR_NOSUCHJOB);
    }
    np = NULL;
    for (pp = proclist.p_next; pp; pp = pp->p_next)
	if (pp->p_pid == pp->p_jobid) {
	    if (cp[1] == '?') {
		register Char *dp;

		for (dp = pp->p_command; *dp; dp++) {
		    if (*dp != cp[2])
			continue;
		    if (prefix(cp + 2, dp))
			goto match;
		}
	    }
	    else if (prefix(cp + 1, pp->p_command)) {
	match:
		if (np)
		    stderror(ERR_NAME | ERR_AMBIG);
		np = pp;
	    }
	}
    if (np)
	return (np);
    stderror(ERR_NAME | cp[1] == '?' ? ERR_JOBPAT : ERR_NOSUCHJOB);
    /* NOTREACHED */
    return (0);
}


/*
 * pgetcurr - find most recent job that is not pp, preferably stopped
 */
static struct process *
pgetcurr(pp)
    register struct process *pp;
{
    register struct process *np;
    register struct process *xp = NULL;

    for (np = proclist.p_next; np; np = np->p_next)
	if (np != pcurrent && np != pp && np->p_pid &&
	    np->p_pid == np->p_jobid) {
	    if (np->p_flags & PSTOPPED)
		return (np);
	    if (xp == NULL)
		xp = np;
	}
    return (xp);
}

/*
 * donotify - flag the job so as to report termination asynchronously
 */
void
/*ARGSUSED*/
donotify(v, t)
    Char **v;
    struct command *t;
{
    register struct process *pp;

    pp = pfind(*++v);
    pp->p_flags |= PNOTIFY;
}

/*
 * Do the fork and whatever should be done in the child side that
 * should not be done if we are not forking at all (like for simple builtin's)
 * Also do everything that needs any signals fiddled with in the parent side
 *
 * Wanttty tells whether process and/or tty pgrps are to be manipulated:
 *	-1:	leave tty alone; inherit pgrp from parent
 *	 0:	already have tty; manipulate process pgrps only
 *	 1:	want to claim tty; manipulate process and tty pgrps
 * It is usually just the value of tpgrp.
 */

int
pfork(t, wanttty)
    struct command *t;		/* command we are forking for */
    int     wanttty;
{
    register int pid;
    bool    ignint = 0;
    int     pgrp;
    sigset_t omask;

    /*
     * A child will be uninterruptible only under very special conditions.
     * Remember that the semantics of '&' is implemented by disconnecting the
     * process from the tty so signals do not need to ignored just for '&'.
     * Thus signals are set to default action for children unless: we have had
     * an "onintr -" (then specifically ignored) we are not playing with
     * signals (inherit action)
     */
    if (setintr)
	ignint = (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT))
	    || (gointr && eq(gointr, STRminus));
    /*
     * Check for maximum nesting of 16 processes to avoid Forking loops
     */
    if (child == 16)
	stderror(ERR_NESTING, 16);
    /*
     * Hold SIGCHLD until we have the process installed in our table.
     */
    omask = sigblock(sigmask(SIGCHLD));
    while ((pid = fork()) < 0)
	if (setintr == 0)
	    (void) sleep(FORKSLEEP);
	else {
	    (void) sigsetmask(omask);
	    stderror(ERR_NOPROC);
	}
    if (pid == 0) {
	settimes();
	pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
	pflushall();
	pcurrjob = NULL;
	child++;
	if (setintr) {
	    setintr = 0;	/* until I think otherwise */
	    /*
	     * Children just get blown away on SIGINT, SIGQUIT unless "onintr
	     * -" seen.
	     */
	    (void) signal(SIGINT, ignint ? SIG_IGN : SIG_DFL);
	    (void) signal(SIGQUIT, ignint ? SIG_IGN : SIG_DFL);
	    if (wanttty >= 0) {
		/* make stoppable */
		(void) signal(SIGTSTP, SIG_DFL);
		(void) signal(SIGTTIN, SIG_DFL);
		(void) signal(SIGTTOU, SIG_DFL);
	    }
	    (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);
	/*
	 * Nohup and nice apply only to NODE_COMMAND's but it would be nice
	 * (?!?) if you could say "nohup (foo;bar)" Then the parser would have
	 * to know about nice/nohup/time
	 */
	if (t->t_dflg & F_NOHUP)
	    (void) signal(SIGHUP, SIG_IGN);
	if (t->t_dflg & F_NICE)
	    (void) setpriority(PRIO_PROCESS, 0, t->t_nice);
    }
    else {
	if (wanttty >= 0)
	    (void) setpgid(pid, pcurrjob ? pcurrjob->p_jobid : pid);
	palloc(pid, t);
	(void) sigsetmask(omask);
    }

    return (pid);
}

static void
okpcntl()
{
    if (tpgrp == -1)
	stderror(ERR_JOBCONTROL);
    if (tpgrp == 0)
	stderror(ERR_JOBCTRLSUB);
}

/*
 * if we don't have vfork(), things can still go in the wrong order
 * resulting in the famous 'Stopped (tty output)'. But some systems
 * don't permit the setpgid() call, (these are more recent secure
 * systems such as ibm's aix). Then we'd rather print an error message
 * than hang the shell!
 * I am open to suggestions how to fix that.
 */
void
pgetty(wanttty, pgrp)
    int     wanttty, pgrp;
{
    sigset_t omask = 0;

    /*
     * christos: I am blocking the tty signals till I've set things
     * correctly....
     */
    if (wanttty > 0)
	omask = sigblock(sigmask(SIGTSTP)|sigmask(SIGTTIN)|sigmask(SIGTTOU));
    /*
     * From: Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
     * Don't check for tpgrp >= 0 so even non-interactive shells give
     * background jobs process groups Same for the comparison in the other part
     * of the #ifdef
     */
    if (wanttty >= 0)
	if (setpgid(0, pgrp) == -1) {
	    (void) fprintf(csherr, "csh: setpgid error.\n");
	    xexit(0);
	}

    if (wanttty > 0) {
	(void) tcsetpgrp(FSHTTY, pgrp);
	(void) sigsetmask(omask);
    }

    if (tpgrp > 0)
	tpgrp = 0;		/* gave tty away */
}