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sh.proc.c

/* $Header: /p/tcsh/cvsroot/tcsh/sh.proc.c,v 3.119 2011/04/14 18:25:25 christos Exp $ */
/*
 * sh.proc.c: Job manipulations
 */
/*-
 * Copyright (c) 1980, 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include "sh.h"

RCSID("$tcsh: sh.proc.c,v 3.119 2011/04/14 18:25:25 christos Exp $")

#include "ed.h"
#include "tc.h"
#include "tc.wait.h"

#ifdef WINNT_NATIVE
#undef POSIX
#define POSIX
#endif /* WINNT_NATIVE */
#ifdef aiws
# undef HZ
# define HZ 16
#endif /* aiws */

#if defined(_BSD) || (defined(IRIS4D) && __STDC__) || defined(__lucid) || defined(__linux__) || defined(__GNU__) || defined(__GLIBC__)
# if !defined(__ANDROID__)
#  define BSDWAIT
# endif
#endif /* _BSD || (IRIS4D && __STDC__) || __lucid || glibc */
#ifndef WTERMSIG
# define WTERMSIG(w)    (((union wait *) &(w))->w_termsig)
# ifndef BSDWAIT
#  define BSDWAIT
# endif /* !BSDWAIT */
#endif /* !WTERMSIG */
#ifndef WEXITSTATUS
# define WEXITSTATUS(w) (((union wait *) &(w))->w_retcode)
#endif /* !WEXITSTATUS */
#ifndef WSTOPSIG
# define WSTOPSIG(w)    (((union wait *) &(w))->w_stopsig)
#endif /* !WSTOPSIG */

#ifdef __osf__
# ifndef WCOREDUMP
#  define WCOREDUMP(x) (_W_INT(x) & WCOREFLAG)
# endif
#endif

#ifndef WCOREDUMP
# ifdef BSDWAIT
#  define WCOREDUMP(w)  (((union wait *) &(w))->w_coredump)
# else /* !BSDWAIT */
#  define WCOREDUMP(w)  ((w) & 0200)
# endif /* !BSDWAIT */
#endif /* !WCOREDUMP */

#ifndef JOBDEBUG
# define jobdebug_xprintf(x)  (void)0
# define jobdebug_flush()     (void)0
#else
# define jobdebug_xprintf(s)  xprintf s
# define jobdebug_flush()     flush()
#endif

/*
 * C Shell - functions that manage processes, handling hanging, termination
 */

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

#ifdef BSDTIMES
# ifdef convex
/* use 'cvxrusage' to get parallel statistics */
static struct cvxrusage zru = {{0L, 0L}, {0L, 0L}, 0L, 0L, 0L, 0L,
                        0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L,
                        {0L, 0L}, 0LL, 0LL, 0LL, 0LL, 0L, 0L, 0L,
                        0LL, 0LL, {0L, 0L, 0L, 0L, 0L}};
# else
static struct rusage zru;
# endif /* convex */
#else /* !BSDTIMES */
# ifdef _SEQUENT_
static struct process_stats zru = {{0L, 0L}, {0L, 0L}, 0, 0, 0, 0, 0, 0, 0,
                           0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
# else /* !_SEQUENT_ */
#  ifdef _SX
static struct tms zru = {0, 0, 0, 0}, lru = {0, 0, 0, 0};
#  else     /* !_SX */
static struct tms zru = {0L, 0L, 0L, 0L}, lru = {0L, 0L, 0L, 0L};
#  endif    /* !_SX */
# endif     /* !_SEQUENT_ */
#endif /* !BSDTIMES */

#ifndef BSDTIMES
static int timesdone;   /* shtimes buffer full ? */
#endif /* BSDTIMES */

#ifndef RUSAGE_CHILDREN
# define    RUSAGE_CHILDREN   -1
#endif /* RUSAGE_CHILDREN */

static      void         pflushall  (void);
static      void         pflush           (struct process *);
static      void         pfree            (struct process *);
static      void         pclrcurr   (struct process *);
static      void         morecommand      (size_t);
static      void         padd       (struct command *);
static      int          pprint           (struct process *, int);
static      void         ptprint    (struct process *);
static      void         pads       (Char *);
static      void         pkill            (Char **, int);
static      struct process    *pgetcurr   (struct process *);
static      void         okpcntl    (void);
static      void         setttypgrp (int);

/*
 * pchild - call queued 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!
 */
void
pchild(void)
{
    struct process *pp;
    struct process *fp;
    pid_t pid;
#ifdef BSDWAIT
    union wait w;
#else /* !BSDWAIT */
    int     w;
#endif /* !BSDWAIT */
    int     jobflags;
#ifdef BSDTIMES
    struct sysrusage ru;
#else /* !BSDTIMES */
# ifdef _SEQUENT_
    struct process_stats ru;
    struct process_stats cpst1, cpst2;
    timeval_t tv;
# else /* !_SEQUENT_ */
    struct tms proctimes;

    if (!timesdone) {
      timesdone++;
      (void) times(&shtimes);
    }
# endif     /* !_SEQUENT_ */
#endif /* !BSDTIMES */

    jobdebug_xprintf(("pchild()\n"));

loop:
    jobdebug_xprintf(("Waiting...\n"));
    jobdebug_flush();
    errno = 0;                /* reset, just in case */

#ifndef WINNT_NATIVE
# ifdef BSDJOBS
#  ifdef BSDTIMES
#   ifdef convex
    /* use 'cvxwait' to get parallel statistics */
    pid = cvxwait(&w,
        (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG), &ru);
#   else
    /* both a wait3 and rusage */
#    if !defined(BSDWAIT) || defined(NeXT) || defined(MACH) || defined(__linux__) || defined(__GNU__) || defined(__GLIBC__) || (defined(IRIS4D) && SYSVREL <= 3) || defined(__lucid) || defined(__osf__)
    pid = wait3(&w,
       (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG), &ru);
#    else /* BSDWAIT */
    pid = wait3(&w.w_status,
       (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG), &ru);
#    endif /* BSDWAIT */
#   endif /* convex */
#  else /* !BSDTIMES */
#   ifdef _SEQUENT_
    (void) get_process_stats(&tv, PS_SELF, 0, &cpst1);
    pid = waitpid(-1, &w,
          (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG));
    (void) get_process_stats(&tv, PS_SELF, 0, &cpst2);
    pr_stat_sub(&cpst2, &cpst1, &ru);
#   else    /* !_SEQUENT_ */
#    ifndef POSIX
    /* we have a wait3, but no rusage stuff */
    pid = wait3(&w.w_status,
       (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG), 0);
#    else /* POSIX */
    pid = waitpid(-1, &w,
          (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG));
#    endif /* POSIX */
#   endif /* !_SEQUENT_ */
#  endif    /* !BSDTIMES */
# else /* !BSDJOBS */
#  ifdef BSDTIMES
#   define HAVEwait3
    /* both a wait3 and rusage */
#   ifdef hpux
    pid = wait3(&w.w_status, WNOHANG, 0);
#   else    /* !hpux */
#     ifndef BSDWAIT
    pid = wait3(&w, WNOHANG, &ru);
#     else
    pid = wait3(&w.w_status, WNOHANG, &ru);
#     endif /* BSDWAIT */
#   endif /* !hpux */
#  else /* !BSDTIMES */
#   ifdef ODT  /* For Sco Unix 3.2.0 or ODT 1.0 */
#    define HAVEwait3
    pid = waitpid(-1, &w,
          (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG));
#   endif /* ODT */         
#   if defined(aiws) || defined(uts)
#    define HAVEwait3
    pid = wait3(&w.w_status, 
      (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG), 0);
#   endif /* aiws || uts */
#   ifndef HAVEwait3
#    ifndef BSDWAIT
     /* no wait3, therefore no rusage */
     /* on Sys V, this may hang.  I hope it's not going to be a problem */
    pid = wait(&w);
#    else /* BSDWAIT */
     /* 
      * XXX: for greater than 3 we should use waitpid(). 
      * but then again, SVR4 falls into the POSIX/BSDJOBS category.
      */
    pid = wait(&w.w_status);
#    endif /* BSDWAIT */
#   endif /* !HAVEwait3 */
#  endif    /* !BSDTIMES */
# endif /* !BSDJOBS */
#else /* WINNT_NATIVE */
    pid = waitpid(-1, &w,
          (setintr && (intty || insource) ? WNOHANG | WUNTRACED : WNOHANG));
#endif /* WINNT_NATIVE */

    jobdebug_xprintf(("parent %d pid %d, retval %x termsig %x retcode %x\n",
                  (int)getpid(), (int)pid, w, WTERMSIG(w),
                  WEXITSTATUS(w)));
    jobdebug_flush();

    if ((pid == 0) || (pid == -1)) {
      (void)handle_pending_signals();
      jobdebug_xprintf(("errno == %d\n", errno));
      if (errno == EINTR)
          goto loop;
      goto end;
    }
    for (pp = proclist.p_next; pp != NULL; pp = pp->p_next)
      if (pid == pp->p_procid)
          goto found;
#if !defined(BSDJOBS) && !defined(WINNT_NATIVE)
    /* this should never have happened */
    stderror(ERR_SYNC, pid);
    xexit(0);
#else /* BSDJOBS || WINNT_NATIVE */
    goto loop;
#endif /* !BSDJOBS && !WINNT_NATIVE */
found:
    pp->p_flags &= ~(PRUNNING | PSTOPPED | PREPORTED);
    if (WIFSTOPPED(w)) {
      pp->p_flags |= PSTOPPED;
      pp->p_reason = WSTOPSIG(w);
    }
    else {
      if (pp->p_flags & (PTIME | PPTIME) || adrof(STRtime))
#ifndef BSDTIMES
# ifdef _SEQUENT_
          (void) get_process_stats(&pp->p_etime, PS_SELF, NULL, NULL);
# else      /* !_SEQUENT_ */
          pp->p_etime = times(&proctimes);
# endif     /* !_SEQUENT_ */
#else /* BSDTIMES */
          (void) gettimeofday(&pp->p_etime, NULL);
#endif /* BSDTIMES */


#if defined(BSDTIMES) || defined(_SEQUENT_)
      pp->p_rusage = ru;
#else /* !BSDTIMES && !_SEQUENT_ */
      (void) times(&proctimes);
      pp->p_utime = proctimes.tms_cutime - shtimes.tms_cutime;
      pp->p_stime = proctimes.tms_cstime - shtimes.tms_cstime;
      shtimes = proctimes;
#endif /* !BSDTIMES && !_SEQUENT_ */
      if (WIFSIGNALED(w)) {
          if (WTERMSIG(w) == SIGINT)
            pp->p_flags |= PINTERRUPTED;
          else
            pp->p_flags |= PSIGNALED;
          if (WCOREDUMP(w))
            pp->p_flags |= PDUMPED;
          pp->p_reason = WTERMSIG(w);
      }
      else {
          pp->p_reason = WEXITSTATUS(w);
          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) &&
#ifdef BSDTIMES
          fp->p_rusage.ru_utime.tv_sec + fp->p_rusage.ru_stime.tv_sec
#else /* !BSDTIMES */
# ifdef _SEQUENT_
          fp->p_rusage.ps_utime.tv_sec + fp->p_rusage.ps_stime.tv_sec
# else /* !_SEQUENT_ */
#  ifndef POSIX
          (fp->p_utime + fp->p_stime) / HZ
#  else /* POSIX */
          (fp->p_utime + fp->p_stime) / clk_tck
#  endif /* POSIX */
# endif /* !_SEQUENT_ */
#endif /* !BSDTIMES */
          >= atoi(short2str(varval(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_procid != 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 notdef
            jobflags & PAEXITED ||
#endif /* notdef */
            !eq(dcwd->di_name, fp->p_cwd->di_name))) {
          /* PWP: print a newline after ^C */
            if (jobflags & PINTERRUPTED) {
                xputchar('\r' | QUOTE);
                xputchar('\n');
            }
#ifdef notdef
            else if ((jobflags & (PTIME|PSTOPPED)) == PTIME)
                ptprint(fp);
#endif /* notdef */
          }
      }
      else {
          if (jobflags & PNOTIFY || adrof(STRnotify)) {
              xputchar('\r' | QUOTE);
            xputchar('\n');
            (void) pprint(pp, NUMBER | NAME | REASON);
            if ((jobflags & PSTOPPED) == 0)
                pflush(pp);
            if (GettingInput) {
                errno = 0;
                (void) Rawmode();
#ifdef notdef
                /*
                 * don't really want to do that, because it
                 * will erase our message in case of multi-line
                 * input
                 */
                ClearLines();
#endif /* notdef */
                ClearDisp();
                Refresh();
            }
          }
          else {
            fp->p_flags |= PNEEDNOTE;
            neednote = 1;
          }
      }
    }
#if defined(BSDJOBS) || defined(HAVEwait3) ||defined(WINNT_NATIVE)
    goto loop;
#endif /* BSDJOBS || HAVEwait3 */
 end:
    ;
}

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

    neednote = 0;
    for (pp = proclist.p_next; pp != NULL; pp = pp->p_next) {
      if (pp->p_flags & PNEEDNOTE) {
          pchild_disabled++;
          cleanup_push(&pchild_disabled, disabled_cleanup);
          pp->p_flags &= ~PNEEDNOTE;
          flags = pprint(pp, NUMBER | NAME | REASON);
          if ((flags & (PRUNNING | PSTOPPED)) == 0)
            pflush(pp);
          cleanup_until(&pchild_disabled);
      }
    }
}


static void
pfree(struct process *pp)
{     
    xfree(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(pp);
}


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

    /*
     * Here's where dead procs get flushed.
     */
    for (pp = (fp = &proclist)->p_next; pp != NULL; pp = (fp = pp)->p_next)
      if (pp->p_procid == 0) {
          fp->p_next = pp->p_next;
          pfree(pp);
          pp = fp;
      }
    pjwait(pcurrjob);
}


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

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

    do {
      if ((fp->p_flags & (PFOREGND | PRUNNING)) == PRUNNING)
        xprintf("%s", CGETS(17, 1, "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;
    sigemptyset(&set);
    sigaddset(&set, SIGINT);
    sigaddset(&set, SIGCHLD);
    (void)sigprocmask(SIG_BLOCK, &set, &oset);
    cleanup_push(&oset, sigprocmask_cleanup);
    pause_mask = oset;
    sigdelset(&pause_mask, SIGCHLD);
    for (;;) {
      (void)handle_pending_signals();
      jobflags = 0;
      do
          jobflags |= fp->p_flags;
      while ((fp = (fp->p_friends)) != pp);
      if ((jobflags & PRUNNING) == 0)
          break;
      jobdebug_xprintf(("%d starting to sigsuspend for SIGCHLD on %d\n",
                    getpid(), fp->p_procid));
      sigsuspend(&pause_mask);
    }
    cleanup_until(&oset);
    jobdebug_xprintf(("%d returned from sigsuspend loop\n", getpid()));
#ifdef BSDJOBS
    if (tpgrp > 0)            /* get tty back */
      (void) tcsetpgrp(FSHTTY, tpgrp);
#endif /* BSDJOBS */
    if ((jobflags & (PSIGNALED | PSTOPPED | PTIME)) ||
      fp->p_cwd == NULL || !eq(dcwd->di_name, fp->p_cwd->di_name)) {
      if (jobflags & PSTOPPED) {
          xputchar('\n');
          if (adrof(STRlistjobs)) {
            Char   *jobcommand[3];

            jobcommand[0] = STRjobs;
            if (eq(varval(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 {
      /* In case of pipelines only the result of the last
       * command should be taken in account */
      if (!anyerror && !(fp->p_flags & PBRACE)
            && ((fp->p_flags & PPOU) || (fp->p_flags & PBACKQ)))
          continue;
      if (fp->p_reason)
          reason = fp->p_flags & (PSIGNALED | PINTERRUPTED) ?
            fp->p_reason | META : fp->p_reason;
    } while ((fp = fp->p_friends) != pp);
    /*
     * Don't report on backquoted jobs, cause it will mess up 
     * their output.
     */
    if ((reason != 0) && (adrof(STRprintexitvalue)) && 
      (pp->p_flags & PBACKQ) == 0)
      xprintf(CGETS(17, 2, "Exit %d\n"), reason);
    reason_str = putn((tcsh_number_t)reason);
    cleanup_push(reason_str, xfree);
    setv(STRstatus, reason_str, VAR_READWRITE);
    cleanup_ignore(reason_str);
    cleanup_until(reason_str);
    if (reason && exiterr)
      exitstat();
    pflush(pp);
}

/*
 * dowait - wait for all processes to finish
 */

/*ARGSUSED*/
void
dowait(Char **v, struct command *c)
{
    struct process *pp;
    sigset_t pause_mask;

    USE(c);
    USE(v);
    pjobs++;
    sigprocmask(SIG_BLOCK, NULL, &pause_mask);
    sigdelset(&pause_mask, SIGCHLD);
    if (setintr)
      sigdelset(&pause_mask, SIGINT);
loop:
    for (pp = proclist.p_next; pp; pp = pp->p_next)
      if (pp->p_procid &&     /* pp->p_procid == pp->p_jobid && */
          pp->p_flags & PRUNNING) {
          (void)handle_pending_signals();
          sigsuspend(&pause_mask);
          if (handle_pending_signals())
            break;
          goto loop;
      }
    pjobs = 0;
}

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

    for (pp = proclist.p_next; pp != NULL; pp = pp->p_next)
      if (pp->p_procid)
          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(struct process *pp)
{
    struct process *np;
    int idx;

    if (pp->p_procid == 0) {
      xprintf("%s", CGETS(17, 3, "BUG: process flushed twice"));
      return;
    }
    while (pp->p_procid != 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_procid = 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(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 *cmdstr;
static size_t cmdmax;
static size_t cmdlen;
static Char *cmdp;
#define CMD_INIT 1024
#define CMD_INCR 64

static void
morecommand(size_t s)
{
    Char *ncmdstr;
    ptrdiff_t d;

    cmdmax += s;
    ncmdstr = xrealloc(cmdstr, cmdmax * sizeof(*cmdstr));
    d = ncmdstr - cmdstr;
    cmdstr = ncmdstr;
    cmdp += d;
}

/* GrP
 * unparse - Export padd() functionality 
 */
Char *
unparse(struct command *t)
{
    if (cmdmax == 0)
      morecommand(CMD_INIT);
    cmdp = cmdstr;
    cmdlen = 0;
    padd(t);
    *cmdp++ = '\0';
    return Strsave(cmdstr);
}


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

    pp = xcalloc(1, sizeof(struct process));
    pp->p_procid = pid;
    pp->p_parentid = shpgrp;
    pp->p_flags = ((t->t_dflg & F_AMPERSAND) ? 0 : PFOREGND) | PRUNNING;
    if (t->t_dflg & F_TIME)
      pp->p_flags |= PPTIME;
    if (t->t_dflg & F_BACKQ)
      pp->p_flags |= PBACKQ;
    if (t->t_dflg & F_HUP)
      pp->p_flags |= PHUP;
    if (t->t_dcom && t->t_dcom[0] && (*t->t_dcom[0] == '{'))
      pp->p_flags |= PBRACE;
    if (cmdmax == 0)
      morecommand(CMD_INIT);
    cmdp = cmdstr;
    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 |= PDIAG;
    }
    pp->p_command = Strsave(cmdstr);
    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_procid;
      for (fp = pcurrjob; fp->p_friends != pcurrjob; fp = fp->p_friends)
          continue;
      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;
#ifdef BSDTIMES
    (void) gettimeofday(&pp->p_btime, NULL);
#else /* !BSDTIMES */
# ifdef _SEQUENT_
    (void) get_process_stats(&pp->p_btime, PS_SELF, NULL, NULL);
# else /* !_SEQUENT_ */
    {
      struct tms tmptimes;

      pp->p_btime = times(&tmptimes);
    }
# endif /* !_SEQUENT_ */
#endif /* !BSDTIMES */
}

static void
padd(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;
      default:
          break;
      }
      padd(t->t_dcdr);
      return;

    default:
      break;
    }
    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(Char *cp)
{
    size_t i, len;

    /*
     * 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);

    len = cmdlen + i + CMD_INCR;
    if (len >= cmdmax)
      morecommand(len);
    (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(void)
{
    pholdjob = pcurrjob;
    pcurrjob = NULL;
}

void
psavejob_cleanup(void *dummy)
{
    USE(dummy);
    pcurrjob = pholdjob;
    pholdjob = NULL;
}

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

    if (pcurrjob && (pcurrjob->p_flags & (PFOREGND | PSTOPPED)) == 0) {
      pp = pcurrjob;
      pcurrjob = NULL;
      while (pp->p_procid != pp->p_jobid)
          pp = pp->p_friends;
      xprintf("[%d]", pp->p_index);
      tp = pp;
      do {
          xprintf(" %d", pp->p_procid);
          pp = pp->p_friends;
      } while (pp != tp);
      xputchar('\n');
    }
    pholdjob = pcurrjob = 0;
}

/*
 * pprint - print a job
 */

/*
 * Hacks have been added for SVR4 to deal with pipe's being spawned in
 * reverse order
 *
 * David Dawes (dawes@physics.su.oz.au) Oct 1991
 */

static int
pprint(struct process *pp, int flag)
{
    int status, reason;
    struct process *tp;
    int     jobflags, pstatus, pcond;
    const char *format;

#ifdef BACKPIPE
    struct process *pipehead = NULL, *pipetail = NULL, *pmarker = NULL;
    int inpipe = 0;
#endif /* BACKPIPE */

    while (pp->p_procid != 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 {
#ifdef BACKPIPE
      /*
       * The pipeline is reversed, so locate the real head of the pipeline
       * if pp is at the tail of a pipe (and not already in a pipeline)
       */
      if ((pp->p_friends->p_flags & PPOU) && !inpipe && (flag & NAME)) {
          inpipe = 1;
          pipetail = pp;
          do 
            pp = pp->p_friends;
          while (pp->p_friends->p_flags & PPOU);
          pipehead = pp;
          pmarker = pp;
      /*
       * pmarker is used to hold the place of the proc being processed, so
       * we can search for the next one downstream later.
       */
      }
      pcond = (tp != pp || (inpipe && tp == pp));
#else /* !BACKPIPE */
      pcond = (tp != pp);
#endif /* BACKPIPE */       

      jobflags |= pp->p_flags;
      pstatus = (int) (pp->p_flags & PALLSTATES);
      if (pcond && linp != linbuf && !(flag & FANCY) &&
          ((pstatus == status && pp->p_reason == reason) ||
           !(flag & REASON)))
          xputchar(' ');
      else {
          if (pcond && linp != linbuf)
            xputchar('\n');
          if (flag & NUMBER) {
#ifdef BACKPIPE
            pcond = ((pp == tp && !inpipe) ||
                   (inpipe && pipetail == tp && pp == pipehead));
#else /* BACKPIPE */
            pcond = (pp == tp);
#endif /* BACKPIPE */
            if (pcond)
                xprintf("[%d]%s %c ", pp->p_index,
                      pp->p_index < 10 ? " " : "",
                      pp == pcurrent ? '+' :
                      (pp == pprevious ? '-' : ' '));
            else
                xprintf("       ");
          }
          if (flag & FANCY) {
            xprintf("%5d ", pp->p_procid);
#ifdef TCF
            xprintf("%11s ", sitename(pp->p_procid));
#endif /* TCF */
          }
          if (flag & (REASON | AREASON)) {
            if (flag & NAME)
                format = "%-30s";
            else
                format = "%s";
            if (pstatus == status) {
                if (pp->p_reason == reason) {
                  xprintf(format, "");
                  goto prcomd;
                }
                else
                  reason = (int) pp->p_reason;
            }
            else {
                status = pstatus;
                reason = (int) pp->p_reason;
            }
            switch (status) {

            case PRUNNING:
                xprintf(format, CGETS(17, 4, "Running "));
                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))) {
                  char *ptr;
                  int free_ptr;

                  free_ptr = 0;
                  ptr = (char *)(intptr_t)mesg[pp->p_reason & 0177].pname;
                  if (ptr == NULL) {
                      ptr = xasprintf("%s %d", CGETS(17, 5, "Signal"),
                                  pp->p_reason & 0177);
                      cleanup_push(ptr, xfree);
                      free_ptr = 1;
                  }
                  xprintf(format, ptr);
                  if (free_ptr != 0)
                      cleanup_until(ptr);
                }
                else
                  reason = -1;
                break;

            case PNEXITED:
            case PAEXITED:
                if (flag & REASON) {
                  if (pp->p_reason)
                      xprintf(CGETS(17, 6, "Exit %-25d"), pp->p_reason);
                  else
                      xprintf(format, CGETS(17, 7, "Done"));
                }
                break;

            default:
                xprintf(CGETS(17, 8, "BUG: status=%-9o"),
                      status);
            }
          }
      }
prcomd:
      if (flag & NAME) {
          xprintf("%S", pp->p_command);
          if (pp->p_flags & PPOU)
            xprintf(" |");
          if (pp->p_flags & PDIAG)
            xprintf("&");
      }
      if (flag & (REASON | AREASON) && pp->p_flags & PDUMPED)
          xprintf("%s", CGETS(17, 9, " (core dumped)"));
      if (tp == pp->p_friends) {
          if (flag & AMPERSAND)
            xprintf(" &");
          if (flag & JOBDIR &&
            !eq(tp->p_cwd->di_name, dcwd->di_name)) {
            xprintf("%s", CGETS(17, 10, " (wd: "));
            dtildepr(tp->p_cwd->di_name);
            xprintf(")");
          }
      }
      if (pp->p_flags & PPTIME && !(status & (PSTOPPED | PRUNNING))) {
          if (linp != linbuf)
            xprintf("\n\t");
#if defined(BSDTIMES) || defined(_SEQUENT_)
          prusage(&zru, &pp->p_rusage, &pp->p_etime,
                &pp->p_btime);
#else /* !BSDTIMES && !SEQUENT */
          lru.tms_utime = pp->p_utime;
          lru.tms_stime = pp->p_stime;
          lru.tms_cutime = 0;
          lru.tms_cstime = 0;
          prusage(&zru, &lru, pp->p_etime,
                pp->p_btime);
#endif /* !BSDTIMES && !SEQUENT */

      }
#ifdef BACKPIPE
      pcond = ((tp == pp->p_friends && !inpipe) ||
             (inpipe && pipehead->p_friends == tp && pp == pipetail));
#else  /* !BACKPIPE */
      pcond = (tp == pp->p_friends);
#endif /* BACKPIPE */
      if (pcond) {
          if (linp != linbuf)
            xputchar('\n');
          if (flag & SHELLDIR && !eq(tp->p_cwd->di_name, dcwd->di_name)) {
            xprintf("%s", CGETS(17, 11, "(wd now: "));
            dtildepr(dcwd->di_name);
            xprintf(")\n");
          }
      }
#ifdef BACKPIPE
      if (inpipe) {
          /*
           * if pmaker == pipetail, we are finished that pipeline, and
           * can now skip to past the head
           */
          if (pmarker == pipetail) {
            inpipe = 0;
            pp = pipehead;
          }
          else {
          /*
           * set pp to one before the one we want next, so the while below
           * increments to the correct spot.
           */
            do
                pp = pp->p_friends;
            while (pp->p_friends->p_friends != pmarker);
            pmarker = pp->p_friends;
          }
      }
      pcond = ((pp = pp->p_friends) != tp || inpipe);
#else /* !BACKPIPE */
      pcond = ((pp = pp->p_friends) != tp);
#endif /* BACKPIPE */
    } while (pcond);

    if (jobflags & PTIME && (jobflags & (PSTOPPED | PRUNNING)) == 0) {
      if (jobflags & NUMBER)
          xprintf("       ");
      ptprint(tp);
    }
    return (jobflags);
}

/*
 * All 4.3 BSD derived implementations are buggy and I've had enough.
 * The following implementation produces similar code and works in all
 * cases. The 4.3BSD one works only for <, >, !=
 */
# undef timercmp
#  define timercmp(tvp, uvp, cmp) \
      (((tvp)->tv_sec == (uvp)->tv_sec) ? \
         ((tvp)->tv_usec cmp (uvp)->tv_usec) : \
         ((tvp)->tv_sec  cmp (uvp)->tv_sec))

static void
ptprint(struct process *tp)
{
#ifdef BSDTIMES
    struct timeval tetime, diff;
    static struct timeval ztime;
    struct sysrusage ru;
    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);
#else /* !BSDTIMES */
# ifdef _SEQUENT_
    timeval_t tetime, diff;
    static timeval_t ztime;
    struct process_stats ru;
    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);
# else /* !_SEQUENT_ */
#  ifndef POSIX
    static time_t ztime = 0;
    static time_t zu_time = 0;
    static time_t zs_time = 0;
    time_t  tetime, diff;
    time_t  u_time, s_time;

#  else     /* POSIX */
    static clock_t ztime = 0;
    static clock_t zu_time = 0;
    static clock_t zs_time = 0;
    clock_t tetime, diff;
    clock_t u_time, s_time;

#  endif /* POSIX */
    struct tms zts, rts;
    struct process *pp = tp;

    u_time = zu_time;
    s_time = zs_time;
    tetime = ztime;
    do {
      u_time += pp->p_utime;
      s_time += pp->p_stime;
      diff = pp->p_etime - pp->p_btime;
      if (diff > tetime)
          tetime = diff;
    } while ((pp = pp->p_friends) != tp);
    zts.tms_utime = zu_time;
    zts.tms_stime = zs_time;
    zts.tms_cutime = 0;
    zts.tms_cstime = 0;
    rts.tms_utime = u_time;
    rts.tms_stime = s_time;
    rts.tms_cutime = 0;
    rts.tms_cstime = 0;
    prusage(&zts, &rts, tetime, ztime);
# endif /* !_SEQUENT_ */
#endif      /* !BSDTIMES */
}

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

    USE(c);
    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_procid == pp->p_jobid) {
            pp->p_flags &= ~PNEEDNOTE;
            if (!(pprint(pp, flag) & (PRUNNING | PSTOPPED)))
                pflush(pp);
            break;
          }
}

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

    USE(c);
    okpcntl();
    ++v;
    do {
      pp = pfind(*v);
      if (!pstart(pp, 1)) {
          pp->p_procid = 0;
          stderror(ERR_NAME|ERR_BADJOB, pp->p_command, strerror(errno));
          continue;
      }
      pjwait(pp);
    } while (*v && *++v);
}

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

    USE(c);
    okpcntl();
    pp = pfind(v[0]);
    if (!pstart(pp, 1)) {
      pp->p_procid = 0;
      stderror(ERR_NAME|ERR_BADJOB, pp->p_command, strerror(errno));
      return;
    }
    pjwait(pp);
}

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

    USE(c);
    okpcntl();
    ++v;
    do {
      pp = pfind(*v);
      if (!pstart(pp, 0)) {
          pp->p_procid = 0;
          stderror(ERR_NAME|ERR_BADJOB, pp->p_command, strerror(errno));
      }
    } while (*v && *++v);
}

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

    USE(c);
    pp = pfind(v[0]);
    if (!pstart(pp, 0)) {
      pp->p_procid = 0;
      stderror(ERR_NAME|ERR_BADJOB, pp->p_command, strerror(errno));
    }
}

/*
 * dostop - builtin - stop the job
 */
/*ARGSUSED*/
void
dostop(Char **v, struct command *c)
{
    USE(c);
#ifdef BSDJOBS
    pkill(++v, SIGSTOP);
#endif /* BSDJOBS */
}

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

    USE(c);
    v++;
    if (v[0] && v[0][0] == '-') {
      if (v[0][1] == 'l') {
          for (signum = 0; signum <= nsig; signum++) {
            if ((name = mesg[signum].iname) != NULL) {
                len += strlen(name) + 1;
                if (len >= TermH - 1) {
                  xputchar('\n');
                  len = strlen(name) + 1;
                }
                xprintf("%s ", name);
            }
          }
          xputchar('\n');
          return;
      }
      sigptr = &v[0][1];
      if (v[0][1] == 's') {
          if (v[1]) {
            v++;
            sigptr = &v[0][0];
          } else {
            stderror(ERR_NAME | ERR_TOOFEW);
          }
      }
      if (Isdigit(*sigptr)) {
          char *ep;
          signum = strtoul(short2str(sigptr), &ep, 0);
          if (*ep || signum < 0 || signum > (MAXSIG-1))
            stderror(ERR_NAME | ERR_BADSIG);
      }
      else {
          for (signum = 0; signum <= nsig; signum++)
            if (mesg[signum].iname &&
                eq(sigptr, str2short(mesg[signum].iname)))
                goto gotsig;
          setname(short2str(sigptr));
          stderror(ERR_NAME | ERR_UNKSIG);
      }
gotsig:
      v++;
    }
    else
      signum = SIGTERM;
    pkill(v, signum);
}

static void
pkill(Char **v, int signum)
{
    struct process *pp, *np;
    int jobflags = 0, err1 = 0;
    pid_t     pid;
    Char *cp, **vp, **globbed;

    /* Avoid globbing %?x patterns */
    for (vp = v; vp && *vp; vp++)
      if (**vp == '%')
          (void) quote(*vp);

    v = glob_all_or_error(v);
    globbed = v;
    cleanup_push(globbed, blk_cleanup);

    pchild_disabled++;
    cleanup_push(&pchild_disabled, disabled_cleanup);
    if (setintr) {
      pintr_disabled++;
      cleanup_push(&pintr_disabled, disabled_cleanup);
    }

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

          case SIGSTOP:
          case SIGTSTP:
          case SIGTTIN:
          case SIGTTOU:
            if ((jobflags & PRUNNING) == 0) {
# ifdef SUSPENDED
                xprintf(CGETS(17, 12, "%S: Already suspended\n"), cp);
# else /* !SUSPENDED */
                xprintf(CGETS(17, 13, "%S: Already stopped\n"), cp);
# endif /* !SUSPENDED */
                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:
            if (!pstart(pp, 0)) {
                pp->p_procid = 0;
                stderror(ERR_NAME|ERR_BADJOB, pp->p_command,
                       strerror(errno));
            }
            goto cont;
          default:
            break;
          }
#endif /* BSDJOBS */
          if (killpg(pp->p_jobid, signum) < 0) {
            xprintf("%S: %s\n", cp, strerror(errno));
            err1++;
          }
#ifdef BSDJOBS
          if (signum == SIGTERM || signum == SIGHUP)
            (void) killpg(pp->p_jobid, SIGCONT);
#endif /* BSDJOBS */
      }
      else if (!(Isdigit(*cp) || *cp == '-'))
          stderror(ERR_NAME | ERR_JOBARGS);
      else {
          char *ep;
#ifndef WINNT_NATIVE
          pid = strtol(short2str(cp), &ep, 10);
#else
          pid = strtoul(short2str(cp), &ep, 0);
#endif /* WINNT_NATIVE */
          if (*ep)
            stderror(ERR_NAME | ERR_JOBARGS);
          else if (kill(pid, signum) < 0) {
            xprintf("%d: %s\n", pid, strerror(errno));
            err1++;
            goto cont;
          }
#ifdef BSDJOBS
          if (signum == SIGTERM || signum == SIGHUP)
            (void) kill(pid, SIGCONT);
#endif /* BSDJOBS */
      }
cont:
      v++;
    }
    cleanup_until(&pchild_disabled);
    if (err1)
      stderror(ERR_SILENT);
}

/*
 * pstart - start the job in foreground/background
 */
int
pstart(struct process *pp, int foregnd)
{
    int rv = 0;
    struct process *np;
    /* We don't use jobflags in this function right now (see below) */
    /* long    jobflags = 0; */

    pchild_disabled++;
    cleanup_push(&pchild_disabled, disabled_cleanup);
    np = pp;
    do {
      /* We don't use jobflags in this function right now (see below) */
      /* 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);

    /* GrP run jobcmd hook if foregrounding */
    if (foregnd) {
      job_cmd(pp->p_command);
    }

#ifdef BSDJOBS
    if (foregnd) {
      rv = tcsetpgrp(FSHTTY, pp->p_jobid);
    }
    /*
     * 1. child process of csh (shell script) receives SIGTTIN/SIGTTOU
     * 2. parent process (csh) receives SIGCHLD
     * 3. The "csh" signal handling function pchild() is invoked
     *    with a SIGCHLD signal.
     * 4. pchild() calls wait3(WNOHANG) which returns 0.
     *    The child process is NOT ready to be waited for at this time.
     *    pchild() returns without picking-up the correct status
     *    for the child process which generated the SIGCHLD.
     * 5. CONSEQUENCE : csh is UNaware that the process is stopped
     * 6. THIS LINE HAS BEEN COMMENTED OUT : if (jobflags&PSTOPPED)
     *        (beto@aixwiz.austin.ibm.com - aug/03/91)
     * 7. I removed the line completely and added extra checks for
     *    pstart, so that if a job gets attached to and dies inside
     *    a debugger it does not confuse the shell. [christos]
     * 8. on the nec sx-4 there seems to be a problem, which requires
     *    a syscall(151, getpid(), getpid()) in osinit. Don't ask me
     *    what this is doing. [schott@rzg.mpg.de]
     */

    if (rv != -1)
      rv = killpg(pp->p_jobid, SIGCONT);
#endif /* BSDJOBS */
    cleanup_until(&pchild_disabled);
    return rv != -1;
}

void
panystop(int neednl)
{
    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(Char *cp)
{
    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_procid == 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_procid == pp->p_jobid) {
          if (cp[1] == '?') {
            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(struct process *pp)
{
    struct process *np;
    struct process *xp = NULL;

    for (np = proclist.p_next; np; np = np->p_next)
      if (np != pcurrent && np != pp && np->p_procid &&
          np->p_procid == 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
 */
/*ARGSUSED*/
void
donotify(Char **v, struct command *c)
{
    struct process *pp;

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

#ifdef SIGSYNCH
static void
synch_handler(int sno)
{
    USE(sno);
}
#endif /* SIGSYNCH */

/*
 * 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.
 */

pid_t
pfork(struct command *t, int wanttty)
{
    pid_t pid;
    int    ignint = 0;
    pid_t pgrp;
#ifdef SIGSYNCH
    struct sigaction osa, nsa;
#endif /* SIGSYNCH */

    /*
     * 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);
#ifdef SIGSYNCH
    nsa.sa_handler = synch_handler;
    sigfillset(&nsa.sa_mask);
    nsa.sa_flags = SA_RESTART;
    if (sigaction(SIGSYNCH, &nsa, &osa))
      stderror(ERR_SYSTEM, "pfork: sigaction set", strerror(errno));
#endif /* SIGSYNCH */
    /*
     * Hold pchild() until we have the process installed in our table.
     */
    if (wanttty < 0) {
      pchild_disabled++;
      cleanup_push(&pchild_disabled, disabled_cleanup);
    }
    while ((pid = fork()) == -1)
      if (setintr == 0)
          (void) sleep(FORKSLEEP);
      else
          stderror(ERR_NOPROC);
    if (pid == 0) {
      (void)cleanup_push_mark(); /* Never to be popped */
      pchild_disabled = 0;
      settimes();
      pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
      pflushall();
      pcurrjob = NULL;
#if !defined(BSDTIMES) && !defined(_SEQUENT_) 
      timesdone = 0;
#endif /* !defined(BSDTIMES) && !defined(_SEQUENT_) */
      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);
#ifdef BSDJOBS
          if (wanttty >= 0) {
            /* make stoppable */
            (void) signal(SIGTSTP, SIG_DFL);
            (void) signal(SIGTTIN, SIG_DFL);
            (void) signal(SIGTTOU, SIG_DFL);
          }
#endif /* BSDJOBS */
          sigaction(SIGTERM, &parterm, NULL);
      }
      else if (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT)) {
          (void) signal(SIGINT, SIG_IGN);
          (void) signal(SIGQUIT, SIG_IGN);
      }
#ifdef OREO
      signal(SIGIO, SIG_IGN); /* ignore SIGIO in child too */
#endif /* OREO */

      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) {
          int nval = SIGN_EXTEND_CHAR(t->t_nice);
#ifdef HAVE_SETPRIORITY
          if (setpriority(PRIO_PROCESS, 0, nval) == -1 && errno)
            stderror(ERR_SYSTEM, "setpriority", strerror(errno));
#else /* !HAVE_SETPRIORITY */
          (void) nice(nval);
#endif /* !HAVE_SETPRIORITY */
      }
#ifdef F_VER
        if (t->t_dflg & F_VER) {
          tsetenv(STRSYSTYPE, t->t_systype ? STRbsd43 : STRsys53);
          dohash(NULL, NULL);
      }
#endif /* F_VER */
#ifdef SIGSYNCH
      /* rfw 8/89 now parent can continue */
      if (kill(getppid(), SIGSYNCH))
          stderror(ERR_SYSTEM, "pfork child: kill", strerror(errno));
#endif /* SIGSYNCH */

    }
    else {
#ifdef POSIXJOBS
        if (wanttty >= 0) {
          /*
           * `Walking' process group fix from Beto Appleton.
           * (beto@aixwiz.austin.ibm.com)
           * If setpgid fails at this point that means that
           * our process leader has died. We flush the current
           * job and become the process leader ourselves.
           * The parent will figure that out later.
           */
          pgrp = pcurrjob ? pcurrjob->p_jobid : pid;
          if (setpgid(pid, pgrp) == -1 && errno == EPERM) {
            pcurrjob = NULL;
            /* 
             * We don't care if this causes an error here;
             * then we are already in the right process group
             */
            (void) setpgid(pid, pgrp = pid);
          }
      }
#endif /* POSIXJOBS */
      palloc(pid, t);
#ifdef SIGSYNCH
      {
          sigset_t pause_mask;

      /*
       * rfw 8/89 Wait for child to own terminal.  Solves half of ugly
       * synchronization problem.  With this change, we know that the only
       * reason setpgrp to a previous process in a pipeline can fail is that
       * the previous process has already exited. Without this hack, he may
       * either have exited or not yet started to run.  Two uglies become
       * one.
       */
          sigprocmask(SIG_BLOCK, NULL, &pause);
          sigdelset(&pause_mask, SIGCHLD);
          sigdelset(&pause_mask, SIGSYNCH);
          sigsuspend(&pause_mask);
          (void)handle_pending_signals();
          if (sigaction(SIGSYNCH, &osa, NULL))
            stderror(ERR_SYSTEM, "pfork parent: sigaction restore",
                   strerror(errno));
      }
#endif /* SIGSYNCH */

      if (wanttty < 0)
          cleanup_until(&pchild_disabled);
    }
    return (pid);
}

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


static void
setttypgrp(int pgrp)
{
    /*
     * If we are piping out a builtin, eg. 'echo | more' things can go
     * out of sequence, i.e. the more can run before the echo. This
     * can happen even if we have vfork, since the echo will be forked
     * with the regular fork. In this case, we need to set the tty
     * pgrp ourselves. If that happens, then the process will be still
     * alive. And the tty process group will already be set.
     * This should fix the famous sequent problem as a side effect:
     *    The controlling terminal is lost if all processes in the
     *    terminal process group are zombies. In this case tcgetpgrp()
     *    returns 0. If this happens we must set the terminal process
     *    group again.
     */
    if (tcgetpgrp(FSHTTY) != pgrp) {
#ifdef POSIXJOBS
      struct sigaction old;

        /*
       * tcsetpgrp will set SIGTTOU to all the the processes in 
       * the background according to POSIX... We ignore this here.
       */
      sigaction(SIGTTOU, NULL, &old);
      signal(SIGTTOU, SIG_IGN);
#endif
      (void) tcsetpgrp(FSHTTY, pgrp);
# ifdef POSIXJOBS
      sigaction(SIGTTOU, &old, NULL);
# endif

    }
}


/*
 * 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), when they do. Then we'd rather print 
 * an error message than hang the shell!
 * I am open to suggestions how to fix that.
 */
void
pgetty(int wanttty, pid_t pgrp)
{
#ifdef BSDJOBS
# ifdef POSIXJOBS
    sigset_t oset, set;
# endif /* POSIXJOBS */

    jobdebug_xprintf(("wanttty %d pid %d opgrp%d pgrp %d tpgrp %d\n",
                  wanttty, (int)getpid(), (int)pgrp, (int)mygetpgrp(),
                  (int)tcgetpgrp(FSHTTY)));
# ifdef POSIXJOBS
    /*
     * christos: I am blocking the tty signals till I've set things
     * correctly....
     */
    if (wanttty > 0) {
      sigemptyset(&set);
      sigaddset(&set, SIGTSTP);
      sigaddset(&set, SIGTTIN);
      (void)sigprocmask(SIG_BLOCK, &set, &oset);
      cleanup_push(&oset, sigprocmask_cleanup);
    }
# endif /* POSIXJOBS */

# ifndef POSIXJOBS
    if (wanttty > 0)
      setttypgrp(pgrp);
# endif /* !POSIXJOBS */

    /*
     * 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) {
# ifdef POSIXJOBS
          /* Walking process group fix; see above */
          if (setpgid(0, pgrp = getpid()) == -1) {
# endif /* POSIXJOBS */
            stderror(ERR_SYSTEM, "setpgid child:\n", strerror(errno));
            xexit(0);
# ifdef POSIXJOBS
          }
          wanttty = pgrp;  /* Now we really want the tty, since we became the
                        * the process group leader
                        */
# endif /* POSIXJOBS */
      }
    }

# ifdef POSIXJOBS
    if (wanttty > 0) {
      setttypgrp(pgrp);
      cleanup_until(&oset);
    }
# endif /* POSIXJOBS */

    jobdebug_xprintf(("wanttty %d pid %d pgrp %d tpgrp %d\n",
                  wanttty, getpid(), mygetpgrp(), tcgetpgrp(FSHTTY)));

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

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