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jobs.c

/*    $NetBSD: jobs.c,v 1.63 2005/06/01 15:41:19 lukem Exp $      */

/*-
 * Copyright (c) 1991, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * 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.
 */

#if 0
#ifndef lint
static char sccsid[] = "@(#)jobs.c  8.5 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: jobs.c,v 1.63 2005/06/01 15:41:19 lukem Exp $");
#endif /* not lint */
#endif

#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>

#include "shell.h"
#if JOBS && !defined(_MSC_VER)
# include <termios.h>
#endif
#include "redir.h"
#include "show.h"
#include "main.h"
#include "parser.h"
#include "nodes.h"
#include "jobs.h"
#include "options.h"
#include "trap.h"
#include "syntax.h"
#include "input.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "mystring.h"
#include "shinstance.h"

//static struct job *jobtab;        /* array of jobs */
//static int njobs;                 /* size of array */
//static int jobs_invalid;          /* set in child */
//MKINIT pid_t backgndpid = -1;     /* pid of last background process */
#if JOBS
//int initialpgrp;            /* pgrp of shell on invocation */
//static int curjob = -1;           /* current job */
#endif
//static int ttyfd = -1;

STATIC void restartjob(shinstance *, struct job *);
STATIC void freejob(shinstance *, struct job *);
STATIC struct job *getjob(shinstance *, const char *, int);
STATIC int dowait(shinstance *, int, struct job *);
STATIC int waitproc(shinstance *, int, struct job *, int *);
STATIC void cmdtxt(shinstance *, union node *);
STATIC void cmdlist(shinstance *, union node *, int);
STATIC void cmdputs(shinstance *, const char *);


/*
 * Turn job control on and off.
 *
 * Note:  This code assumes that the third arg to ioctl is a character
 * pointer, which is true on Berkeley systems but not System V.  Since
 * System V doesn't have job control yet, this isn't a problem now.
 */

//MKINIT int jobctl;

void
setjobctl(shinstance *psh, int on)
{
      if (on == psh->jobctl || psh->rootshell == 0)
            return;
      if (on) {
            int err;
            int i;
            if (psh->ttyfd != -1)
                  shfile_close(&psh->fdtab, psh->ttyfd);
            if ((psh->ttyfd = shfile_open(&psh->fdtab, "/dev/tty", O_RDWR, 0)) == -1) {
                  for (i = 0; i < 3; i++) {
                        if (shfile_isatty(&psh->fdtab, i)
                         && (psh->ttyfd = shfile_dup(&psh->fdtab, i)) != -1)
                              break;
                  }
                  if (i == 3)
                        goto out;
            }
            /* Move to a high fd */
            for (i = 10; i > 2; i--) {
                  if ((err = shfile_fcntl(&psh->fdtab, psh->ttyfd, F_DUPFD, (1 << i) - 1)) != -1)
                        break;
            }
            if (err != -1) {
                  shfile_close(&psh->fdtab, psh->ttyfd);
                  psh->ttyfd = err;
            }
                err = shfile_cloexec(&psh->fdtab, psh->ttyfd, 1);
            if (err == -1) {
                  shfile_close(&psh->fdtab, psh->ttyfd);
                  psh->ttyfd = -1;
                  goto out;
            }
            do { /* while we are in the background */
                  if ((psh->initialpgrp = sh_tcgetpgrp(psh, psh->ttyfd)) < 0) {
out:
                        out2str(psh, "sh: can't access tty; job control turned off\n");
                        mflag(psh) = 0;
                        return;
                  }
                  if (psh->initialpgrp == -1)
                        psh->initialpgrp = sh_getpgrp(psh);
                  else if (psh->initialpgrp != sh_getpgrp(psh)) {
                        sh_killpg(psh, 0, SIGTTIN);
                        continue;
                  }
            } while (0);

            setsignal(psh, SIGTSTP, 0);
            setsignal(psh, SIGTTOU, 0);
            setsignal(psh, SIGTTIN, 0);
            if (sh_getpgid(psh, 0) != psh->rootpid && sh_setpgid(psh, 0, psh->rootpid) == -1)
                  error(psh, "Cannot set process group (%s) at %d",
                      strerror(errno), __LINE__);
            if (sh_tcsetpgrp(psh, psh->ttyfd, psh->rootpid) == -1)
                  error(psh, "Cannot set tty process group (%s) at %d",
                      strerror(errno), __LINE__);
      } else { /* turning job control off */
            if (sh_getpgid(psh, 0) != psh->initialpgrp && sh_setpgid(psh, 0, psh->initialpgrp) == -1)
                  error(psh, "Cannot set process group (%s) at %d",
                      strerror(errno), __LINE__);
            if (sh_tcsetpgrp(psh, psh->ttyfd, psh->initialpgrp) == -1)
                  error(psh, "Cannot set tty process group (%s) at %d",
                      strerror(errno), __LINE__);
            shfile_close(&psh->fdtab, psh->ttyfd);
            psh->ttyfd = -1;
            setsignal(psh, SIGTSTP, 0);
            setsignal(psh, SIGTTOU, 0);
            setsignal(psh, SIGTTIN, 0);
      }
      psh->jobctl = on;
}


#ifdef mkinit
INCLUDE <stdlib.h>

SHELLPROC {
      psh->backgndpid = -1;
#if JOBS
      psh->jobctl = 0;
#endif
}

#endif



#if JOBS
int
fgcmd(shinstance *psh, int argc, char **argv)
{
      struct job *jp;
      int i;
      int status;

      nextopt(psh, "");
      jp = getjob(psh, *psh->argptr, 0);
      if (jp->jobctl == 0)
            error(psh, "job not created under job control");
      out1fmt(psh, "%s", jp->ps[0].cmd);
      for (i = 1; i < jp->nprocs; i++)
            out1fmt(psh, " | %s", jp->ps[i].cmd );
      out1c(psh, '\n');
      output_flushall(psh);

      for (i = 0; i < jp->nprocs; i++)
          if (sh_tcsetpgrp(psh, psh->ttyfd, jp->ps[i].pid) != -1)
                break;

      if (i >= jp->nprocs) {
            error(psh, "Cannot set tty process group (%s) at %d",
                strerror(errno), __LINE__);
      }
      restartjob(psh, jp);
      INTOFF;
      status = waitforjob(psh, jp);
      INTON;
      return status;
}

static void
set_curjob(shinstance *psh, struct job *jp, int mode)
{
      struct job *jp1, *jp2;
      int i, ji;

      ji = (int)(jp - psh->jobtab);

      /* first remove from list */
      if (ji == psh->curjob)
            psh->curjob = jp->prev_job;
      else {
            for (i = 0; i < psh->njobs; i++) {
                  if (psh->jobtab[i].prev_job != ji)
                        continue;
                  psh->jobtab[i].prev_job = jp->prev_job;
                  break;
            }
      }

      /* Then re-insert in correct position */
      switch (mode) {
      case 0:     /* job being deleted */
            jp->prev_job = -1;
            break;
      case 1:     /* newly created job or backgrounded job,
               put after all stopped jobs. */
            if (psh->curjob != -1 && psh->jobtab[psh->curjob].state == JOBSTOPPED) {
                  for (jp1 = psh->jobtab + psh->curjob; ; jp1 = jp2) {
                        if (jp1->prev_job == -1)
                              break;
                        jp2 = psh->jobtab + jp1->prev_job;
                        if (jp2->state != JOBSTOPPED)
                              break;
                  }
                  jp->prev_job = jp1->prev_job;
                  jp1->prev_job = ji;
                  break;
            }
            /* FALLTHROUGH */
      case 2:     /* newly stopped job - becomes psh->curjob */
            jp->prev_job = psh->curjob;
            psh->curjob = ji;
            break;
      }
}

int
bgcmd(shinstance *psh, int argc, char **argv)
{
      struct job *jp;
      int i;

      nextopt(psh, "");
      do {
            jp = getjob(psh, *psh->argptr, 0);
            if (jp->jobctl == 0)
                  error(psh, "job not created under job control");
            set_curjob(psh, jp, 1);
            out1fmt(psh, "[%ld] %s", (long)(jp - psh->jobtab + 1), jp->ps[0].cmd);
            for (i = 1; i < jp->nprocs; i++)
                  out1fmt(psh, " | %s", jp->ps[i].cmd );
            out1c(psh, '\n');
            output_flushall(psh);
            restartjob(psh, jp);
      } while (*psh->argptr && *++psh->argptr);
      return 0;
}


STATIC void
restartjob(shinstance *psh, struct job *jp)
{
      struct procstat *ps;
      int i;

      if (jp->state == JOBDONE)
            return;
      INTOFF;
      for (i = 0; i < jp->nprocs; i++)
            if (sh_killpg(psh, jp->ps[i].pid, SIGCONT) != -1)
                  break;
      if (i >= jp->nprocs)
            error(psh, "Cannot continue job (%s)", strerror(errno));
      for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
            if (WIFSTOPPED(ps->status)) {
                  ps->status = -1;
                  jp->state = JOBRUNNING;
            }
      }
      INTON;
}
#endif

static void
showjob(shinstance *psh, struct output *out, struct job *jp, int mode)
{
      int procno;
      int st;
      struct procstat *ps;
      size_t col;
      char s[64];

#if JOBS
      if (mode & SHOW_PGID) {
            /* just output process (group) id of pipeline */
            outfmt(out, "%ld\n", (long)jp->ps->pid);
            return;
      }
#endif

      procno = jp->nprocs;
      if (!procno)
            return;

      if (mode & SHOW_PID)
            mode |= SHOW_MULTILINE;

      if ((procno > 1 && !(mode & SHOW_MULTILINE))
          || (mode & SHOW_SIGNALLED)) {
            /* See if we have more than one status to report */
            ps = jp->ps;
            st = ps->status;
            do {
                  int st1 = ps->status;
                  if (st1 != st)
                        /* yes - need multi-line output */
                        mode |= SHOW_MULTILINE;
                  if (st1 == -1 || !(mode & SHOW_SIGNALLED) || WIFEXITED(st1))
                        continue;
                  if (WIFSTOPPED(st1) || ((st1 = WTERMSIG(st1) & 0x7f)
                      && st1 != SIGINT && st1 != SIGPIPE))
                        mode |= SHOW_ISSIG;

            } while (ps++, --procno);
            procno = jp->nprocs;
      }

      if (mode & SHOW_SIGNALLED && !(mode & SHOW_ISSIG)) {
            if (jp->state == JOBDONE && !(mode & SHOW_NO_FREE)) {
                  TRACE((psh, "showjob: freeing job %d\n", jp - psh->jobtab + 1));
                  freejob(psh, jp);
            }
            return;
      }

      for (ps = jp->ps; --procno >= 0; ps++) {  /* for each process */
            if (ps == jp->ps)
                  fmtstr(s, 16, "[%ld] %c ",
                        (long)(jp - psh->jobtab + 1),
#if JOBS
                        jp == psh->jobtab + psh->curjob ? '+' :
                        psh->curjob != -1 && jp == psh->jobtab +
                                  psh->jobtab[psh->curjob].prev_job ? '-' :
#endif
                        ' ');
            else
                  fmtstr(s, 16, "      " );
            col = strlen(s);
            if (mode & SHOW_PID) {
                  fmtstr(s + col, 16, "%ld ", (long)ps->pid);
                       col += strlen(s + col);
            }
            if (ps->status == -1) {
                  scopy("Running", s + col);
            } else if (WIFEXITED(ps->status)) {
                  st = WEXITSTATUS(ps->status);
                  if (st)
                        fmtstr(s + col, 16, "Done(%d)", st);
                  else
                        fmtstr(s + col, 16, "Done");
            } else {
#if JOBS
                  if (WIFSTOPPED(ps->status))
                        st = WSTOPSIG(ps->status);
                  else /* WIFSIGNALED(ps->status) */
#endif
                        st = WTERMSIG(ps->status);
                  st &= 0x7f;
                  if (st < NSIG && sys_siglist[st])
                        scopyn(sys_siglist[st], s + col, 32);
                  else
                        fmtstr(s + col, 16, "Signal %d", st);
                  if (WCOREDUMP(ps->status)) {
                        col += strlen(s + col);
                        scopyn(" (core dumped)", s + col,  64 - col);
                  }
            }
            col += strlen(s + col);
            outstr(s, out);
            do {
                  outc(' ', out);
                  col++;
            } while (col < 30);
            outstr(ps->cmd, out);
            if (mode & SHOW_MULTILINE) {
                  if (procno > 0) {
                        outc(' ', out);
                        outc('|', out);
                  }
            } else {
                  while (--procno >= 0)
                        outfmt(out, " | %s", (++ps)->cmd );
            }
            outc('\n', out);
      }
      flushout(out);
      jp->changed = 0;
      if (jp->state == JOBDONE && !(mode & SHOW_NO_FREE))
            freejob(psh, jp);
}


int
jobscmd(shinstance *psh, int argc, char **argv)
{
      int mode, m;
      int sv = psh->jobs_invalid;

      psh->jobs_invalid = 0;
      mode = 0;
      while ((m = nextopt(psh, "lp")))
            if (m == 'l')
                  mode = SHOW_PID;
            else
                  mode = SHOW_PGID;
      if (*psh->argptr)
            do
                  showjob(psh, psh->out1, getjob(psh, *psh->argptr,0), mode);
            while (*++psh->argptr);
      else
            showjobs(psh, psh->out1, mode);
      psh->jobs_invalid = sv;
      return 0;
}


/*
 * Print a list of jobs.  If "change" is nonzero, only print jobs whose
 * statuses have changed since the last call to showjobs.
 *
 * If the shell is interrupted in the process of creating a job, the
 * result may be a job structure containing zero processes.  Such structures
 * will be freed here.
 */

void
showjobs(shinstance *psh, struct output *out, int mode)
{
      int jobno;
      struct job *jp;
      int silent = 0, gotpid;

      TRACE((psh, "showjobs(%x) called\n", mode));

      /* If not even one one job changed, there is nothing to do */
      gotpid = dowait(psh, 0, NULL);
      while (dowait(psh, 0, NULL) > 0)
            continue;
#ifdef JOBS
      /*
       * Check if we are not in our foreground group, and if not
       * put us in it.
       */
      if (mflag(psh) && gotpid != -1 && sh_tcgetpgrp(psh, psh->ttyfd) != sh_getpid(psh)) {
            if (sh_tcsetpgrp(psh, psh->ttyfd, sh_getpid(psh)) == -1)
                  error(psh, "Cannot set tty process group (%s) at %d",
                      strerror(errno), __LINE__);
            TRACE((psh, "repaired tty process group\n"));
            silent = 1;
      }
#endif
      if (psh->jobs_invalid)
            return;

      for (jobno = 1, jp = psh->jobtab ; jobno <= psh->njobs ; jobno++, jp++) {
            if (!jp->used)
                  continue;
            if (jp->nprocs == 0) {
                  freejob(psh, jp);
                  continue;
            }
            if ((mode & SHOW_CHANGED) && !jp->changed)
                  continue;
            if (silent && jp->changed) {
                  jp->changed = 0;
                  continue;
            }
            showjob(psh, out, jp, mode);
      }
}

/*
 * Mark a job structure as unused.
 */

STATIC void
freejob(shinstance *psh, struct job *jp)
{
      INTOFF;
      if (jp->ps != &jp->ps0) {
            ckfree(jp->ps);
            jp->ps = &jp->ps0;
      }
      jp->nprocs = 0;
      jp->used = 0;
#if JOBS
      set_curjob(psh, jp, 0);
#endif
      INTON;
}



int
waitcmd(shinstance *psh, int argc, char **argv)
{
      struct job *job;
      int status, retval;
      struct job *jp;

      nextopt(psh, "");

      if (!*psh->argptr) {
            /* wait for all jobs */
            jp = psh->jobtab;
            if (psh->jobs_invalid)
                  return 0;
            for (;;) {
                  if (jp >= psh->jobtab + psh->njobs) {
                        /* no running procs */
                        return 0;
                  }
                  if (!jp->used || jp->state != JOBRUNNING) {
                        jp++;
                        continue;
                  }
                  if (dowait(psh, 1, (struct job *)NULL) == -1)
                         return 128 + SIGINT;
                  jp = psh->jobtab;
            }
      }

      retval = 127;           /* XXXGCC: -Wuninitialized */
      for (; *psh->argptr; psh->argptr++) {
            job = getjob(psh, *psh->argptr, 1);
            if (!job) {
                  retval = 127;
                  continue;
            }
            /* loop until process terminated or stopped */
            while (job->state == JOBRUNNING) {
                  if (dowait(psh, 1, (struct job *)NULL) == -1)
                         return 128 + SIGINT;
            }
            status = job->ps[job->nprocs].status;
            if (WIFEXITED(status))
                  retval = WEXITSTATUS(status);
#if JOBS
            else if (WIFSTOPPED(status))
                  retval = WSTOPSIG(status) + 128;
#endif
            else {
                  /* XXX: limits number of signals */
                  retval = WTERMSIG(status) + 128;
            }
            if (!iflag(psh))
                  freejob(psh, job);
      }
      return retval;
}



int
jobidcmd(shinstance *psh, int argc, char **argv)
{
      struct job *jp;
      int i;

      nextopt(psh, "");
      jp = getjob(psh, *psh->argptr, 0);
      for (i = 0 ; i < jp->nprocs ; ) {
            out1fmt(psh, "%ld", (long)jp->ps[i].pid);
            out1c(psh, ++i < jp->nprocs ? ' ' : '\n');
      }
      return 0;
}

int
getjobpgrp(shinstance *psh, const char *name)
{
      struct job *jp;

      jp = getjob(psh, name, 1);
      if (jp == 0)
            return 0;
      return -jp->ps[0].pid;
}

/*
 * Convert a job name to a job structure.
 */

STATIC struct job *
getjob(shinstance *psh, const char *name, int noerror)
{
      int jobno = -1;
      struct job *jp;
      int pid;
      int i;
      const char *err_msg = "No such job: %s";

      if (name == NULL) {
#if JOBS
            jobno = psh->curjob;
#endif
            err_msg = "No current job";
      } else if (name[0] == '%') {
            if (is_number(name + 1)) {
                  jobno = number(psh, name + 1) - 1;
            } else if (!name[2]) {
                  switch (name[1]) {
#if JOBS
                  case 0:
                  case '+':
                  case '%':
                        jobno = psh->curjob;
                        err_msg = "No current job";
                        break;
                  case '-':
                        jobno = psh->curjob;
                        if (jobno != -1)
                              jobno = psh->jobtab[jobno].prev_job;
                        err_msg = "No previous job";
                        break;
#endif
                  default:
                        goto check_pattern;
                  }
            } else {
                  struct job *found;
    check_pattern:
                  found = NULL;
                  for (jp = psh->jobtab, i = psh->njobs ; --i >= 0 ; jp++) {
                        if (!jp->used || jp->nprocs <= 0)
                              continue;
                        if ((name[1] == '?'
                              && strstr(jp->ps[0].cmd, name + 2))
                            || prefix(name + 1, jp->ps[0].cmd)) {
                              if (found) {
                                    err_msg = "%s: ambiguous";
                                    found = 0;
                                    break;
                              }
                              found = jp;
                        }
                  }
                  if (found)
                        return found;
            }

      } else if (is_number(name)) {
            pid = number(psh, name);
            for (jp = psh->jobtab, i = psh->njobs ; --i >= 0 ; jp++) {
                  if (jp->used && jp->nprocs > 0
                   && jp->ps[jp->nprocs - 1].pid == pid)
                        return jp;
            }
      }

      if (!psh->jobs_invalid && jobno >= 0 && jobno < psh->njobs) {
            jp = psh->jobtab + jobno;
            if (jp->used)
                  return jp;
      }
      if (!noerror)
            error(psh, err_msg, name);
      return 0;
}



/*
 * Return a new job structure,
 */

struct job *
makejob(shinstance *psh, union node *node, int nprocs)
{
      int i;
      struct job *jp;

      if (psh->jobs_invalid) {
            for (i = psh->njobs, jp = psh->jobtab ; --i >= 0 ; jp++) {
                  if (jp->used)
                        freejob(psh, jp);
            }
            psh->jobs_invalid = 0;
      }

      for (i = psh->njobs, jp = psh->jobtab ; ; jp++) {
            if (--i < 0) {
                  INTOFF;
                  if (psh->njobs == 0) {
                        psh->jobtab = ckmalloc(4 * sizeof psh->jobtab[0]);
                  } else {
                        jp = ckmalloc((psh->njobs + 4) * sizeof psh->jobtab[0]);
                        memcpy(jp, psh->jobtab, psh->njobs * sizeof jp[0]);
                        /* Relocate `ps' pointers */
                        for (i = 0; i < psh->njobs; i++)
                              if (jp[i].ps == &psh->jobtab[i].ps0)
                                    jp[i].ps = &jp[i].ps0;
                        ckfree(psh->jobtab);
                        psh->jobtab = jp;
                  }
                  jp = psh->jobtab + psh->njobs;
                  for (i = 4 ; --i >= 0 ; psh->jobtab[psh->njobs++].used = 0);
                  INTON;
                  break;
            }
            if (jp->used == 0)
                  break;
      }
      INTOFF;
      jp->state = JOBRUNNING;
      jp->used = 1;
      jp->changed = 0;
      jp->nprocs = 0;
#if JOBS
      jp->jobctl = psh->jobctl;
      set_curjob(psh, jp, 1);
#endif
      if (nprocs > 1) {
            jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
      } else {
            jp->ps = &jp->ps0;
      }
      INTON;
      TRACE((psh, "makejob(0x%lx, %d) returns %%%d\n", (long)node, nprocs,
             jp - psh->jobtab + 1));
      return jp;
}


/*
 * Fork off a subshell.  If we are doing job control, give the subshell its
 * own process group.  Jp is a job structure that the job is to be added to.
 * N is the command that will be evaluated by the child.  Both jp and n may
 * be NULL.  The mode parameter can be one of the following:
 *    FORK_FG - Fork off a foreground process.
 *    FORK_BG - Fork off a background process.
 *    FORK_NOJOB - Like FORK_FG, but don't give the process its own
 *               process group even if job control is on.
 *
 * When job control is turned off, background processes have their standard
 * input redirected to /dev/null (except for the second and later processes
 * in a pipeline).
 */

int
forkshell(shinstance *psh, struct job *jp, union node *n, int mode)
{
      int pid;

      TRACE((psh, "forkshell(%%%d, %p, %d) called\n", jp - psh->jobtab, n, mode));
      switch ((pid = sh_fork(psh))) {
      case -1:
            TRACE((psh, "Fork failed, errno=%d\n", errno));
            INTON;
            error(psh, "Cannot fork");
            return -1; /* won't get here */
      case 0:
            forkchild(psh, jp, n, mode, 0);
            return 0;
      default:
            return forkparent(psh, jp, n, mode, pid);
      }
}

int
forkparent(shinstance *psh, struct job *jp, union node *n, int mode, pid_t pid)
{
      int pgrp;

      if (psh->rootshell && mode != FORK_NOJOB && mflag(psh)) {
            if (jp == NULL || jp->nprocs == 0)
                  pgrp = pid;
            else
                  pgrp = jp->ps[0].pid;
            /* This can fail because we are doing it in the child also */
            (void)sh_setpgid(psh, pid, pgrp);
      }
      if (mode == FORK_BG)
            psh->backgndpid = pid;        /* set $! */
      if (jp) {
            struct procstat *ps = &jp->ps[jp->nprocs++];
            ps->pid = pid;
            ps->status = -1;
            ps->cmd[0] = 0;
            if (/* iflag && rootshell && */ n)
                  commandtext(psh, ps, n);
      }
      TRACE((psh, "In parent shell:  child = %d\n", pid));
      return pid;
}

void
forkchild(shinstance *psh, struct job *jp, union node *n, int mode, int vforked)
{
      int wasroot;
      int pgrp;
      const char *devnull = _PATH_DEVNULL;
      const char *nullerr = "Can't open %s";

      wasroot = psh->rootshell;
      TRACE((psh, "Child shell %d\n", sh_getpid(psh)));
      if (!vforked)
            psh->rootshell = 0;

      closescript(psh, vforked);
      clear_traps(psh, vforked);
#if JOBS
      if (!vforked)
            psh->jobctl = 0;        /* do job control only in root shell */
      if (wasroot && mode != FORK_NOJOB && mflag(psh)) {
            if (jp == NULL || jp->nprocs == 0)
                  pgrp = sh_getpid(psh);
            else
                  pgrp = jp->ps[0].pid;
            /* This can fail because we are doing it in the parent also */
            (void)sh_setpgid(psh, 0, pgrp);
            if (mode == FORK_FG) {
                  if (sh_tcsetpgrp(psh, psh->ttyfd, pgrp) == -1)
                        error(psh, "Cannot set tty process group (%s) at %d",
                            strerror(errno), __LINE__);
            }
            setsignal(psh, SIGTSTP, vforked);
            setsignal(psh, SIGTTOU, vforked);
      } else if (mode == FORK_BG) {
            ignoresig(psh, SIGINT, vforked);
            ignoresig(psh, SIGQUIT, vforked);
            if ((jp == NULL || jp->nprocs == 0) &&
                ! fd0_redirected_p(psh)) {
                  shfile_close(&psh->fdtab, 0);
                  if (shfile_open(&psh->fdtab, devnull, O_RDONLY, 0) != 0)
                        error(psh, nullerr, devnull);
            }
      }
#else
      if (mode == FORK_BG) {
            ignoresig(psh, SIGINT, vforked);
            ignoresig(psh, SIGQUIT, vforked);
            if ((jp == NULL || jp->nprocs == 0) &&
                ! fd0_redirected_p(psh)) {
                  shfile_close(&psh->fdtab, 0);
                  if (shfile_open(&psh->fdtab, devnull, O_RDONLY, 0) != 0)
                        error(psh, nullerr, devnull);
            }
      }
#endif
      if (wasroot && iflag(psh)) {
            setsignal(psh, SIGINT, vforked);
            setsignal(psh, SIGQUIT, vforked);
            setsignal(psh, SIGTERM, vforked);
      }

      if (!vforked)
            psh->jobs_invalid = 1;
}

/*
 * Wait for job to finish.
 *
 * Under job control we have the problem that while a child process is
 * running interrupts generated by the user are sent to the child but not
 * to the shell.  This means that an infinite loop started by an inter-
 * active user may be hard to kill.  With job control turned off, an
 * interactive user may place an interactive program inside a loop.  If
 * the interactive program catches interrupts, the user doesn't want
 * these interrupts to also abort the loop.  The approach we take here
 * is to have the shell ignore interrupt signals while waiting for a
 * forground process to terminate, and then send itself an interrupt
 * signal if the child process was terminated by an interrupt signal.
 * Unfortunately, some programs want to do a bit of cleanup and then
 * exit on interrupt; unless these processes terminate themselves by
 * sending a signal to themselves (instead of calling exit) they will
 * confuse this approach.
 */

int
waitforjob(shinstance *psh, struct job *jp)
{
#if JOBS
      int mypgrp = sh_getpgrp(psh);
#endif
      int status;
      int st;

      INTOFF;
      TRACE((psh, "waitforjob(%%%d) called\n", jp - psh->jobtab + 1));
      while (jp->state == JOBRUNNING) {
            dowait(psh, 1, jp);
      }
#if JOBS
      if (jp->jobctl) {
            if (sh_tcsetpgrp(psh, psh->ttyfd, mypgrp) == -1)
                  error(psh, "Cannot set tty process group (%s) at %d",
                      strerror(errno), __LINE__);
      }
      if (jp->state == JOBSTOPPED && psh->curjob != jp - psh->jobtab)
            set_curjob(psh, jp, 2);
#endif
      status = jp->ps[jp->nprocs - 1].status;
      /* convert to 8 bits */
      if (WIFEXITED(status))
            st = WEXITSTATUS(status);
#if JOBS
      else if (WIFSTOPPED(status))
            st = WSTOPSIG(status) + 128;
#endif
      else
            st = WTERMSIG(status) + 128;
      TRACE((psh, "waitforjob: job %d, nproc %d, status %x, st %x\n",
            jp - psh->jobtab + 1, jp->nprocs, status, st ));
#if JOBS
      if (jp->jobctl) {
            /*
             * This is truly gross.
             * If we're doing job control, then we did a TIOCSPGRP which
             * caused us (the shell) to no longer be in the controlling
             * session -- so we wouldn't have seen any ^C/SIGINT.  So, we
             * intuit from the subprocess exit status whether a SIGINT
             * occurred, and if so interrupt ourselves.  Yuck.  - mycroft
             */
            if (WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
                  sh_raise_sigint(psh);/*raise(SIGINT);*/
      }
#endif
      if (! JOBS || jp->state == JOBDONE)
            freejob(psh, jp);
      INTON;
      return st;
}



/*
 * Wait for a process to terminate.
 */

STATIC int
dowait(shinstance *psh, int block, struct job *job)
{
      int pid;
      int status;
      struct procstat *sp;
      struct job *jp;
      struct job *thisjob;
      int done;
      int stopped;

      TRACE((psh, "dowait(%d) called\n", block));
      do {
            pid = waitproc(psh, block, job, &status);
            TRACE((psh, "wait returns pid %d, status %d\n", pid, status));
      } while (pid == -1 && errno == EINTR && psh->gotsig[SIGINT - 1] == 0);
      if (pid <= 0)
            return pid;
      INTOFF;
      thisjob = NULL;
      for (jp = psh->jobtab ; jp < psh->jobtab + psh->njobs ; jp++) {
            if (jp->used) {
                  done = 1;
                  stopped = 1;
                  for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
                        if (sp->pid == -1)
                              continue;
                        if (sp->pid == pid) {
                              TRACE((psh, "Job %d: changing status of proc %d from 0x%x to 0x%x\n", jp - psh->jobtab + 1, pid, sp->status, status));
                              sp->status = status;
                              thisjob = jp;
                        }
                        if (sp->status == -1)
                              stopped = 0;
                        else if (WIFSTOPPED(sp->status))
                              done = 0;
                  }
                  if (stopped) {          /* stopped or done */
                        int state = done ? JOBDONE : JOBSTOPPED;
                        if (jp->state != state) {
                              TRACE((psh, "Job %d: changing state from %d to %d\n", jp - psh->jobtab + 1, jp->state, state));
                              jp->state = state;
#if JOBS
                              if (done)
                                    set_curjob(psh, jp, 0);
#endif
                        }
                  }
            }
      }

      if (thisjob && thisjob->state != JOBRUNNING) {
            int mode = 0;
            if (!psh->rootshell || !iflag(psh))
                  mode = SHOW_SIGNALLED;
            if (job == thisjob)
                  mode = SHOW_SIGNALLED | SHOW_NO_FREE;
            if (mode)
                  showjob(psh, psh->out2, thisjob, mode);
            else {
                  TRACE((psh, "Not printing status, rootshell=%d, job=%p\n",
                        psh->rootshell, job));
                  thisjob->changed = 1;
            }
      }

      INTON;
      return pid;
}



/*
 * Do a wait system call.  If job control is compiled in, we accept
 * stopped processes.  If block is zero, we return a value of zero
 * rather than blocking.
 */
STATIC int
waitproc(shinstance *psh, int block, struct job *jp, int *status)
{
      int flags = 0;

#if JOBS
      if (jp != NULL && jp->jobctl)
            flags |= WUNTRACED;
#endif
      if (block == 0)
            flags |= WNOHANG;
      return sh_waitpid(psh, -1, status, flags);
}

/*
 * return 1 if there are stopped jobs, otherwise 0
 */
//int job_warning = 0;
int
stoppedjobs(shinstance *psh)
{
      int jobno;
      struct job *jp;

      if (psh->job_warning || psh->jobs_invalid)
            return (0);
      for (jobno = 1, jp = psh->jobtab; jobno <= psh->njobs; jobno++, jp++) {
            if (jp->used == 0)
                  continue;
            if (jp->state == JOBSTOPPED) {
                  out2str(psh, "You have stopped jobs.\n");
                  psh->job_warning = 2;
                  return (1);
            }
      }

      return (0);
}

/*
 * Return a string identifying a command (to be printed by the
 * jobs command).
 */

//STATIC char *cmdnextc;
//STATIC int cmdnleft;

void
commandtext(shinstance *psh, struct procstat *ps, union node *n)
{
      int len;

      psh->cmdnextc = ps->cmd;
      if (iflag(psh) || mflag(psh) || sizeof(ps->cmd) < 100)
            len = sizeof(ps->cmd);
      else
            len = sizeof(ps->cmd) / 10;
      psh->cmdnleft = len;
      cmdtxt(psh, n);
      if (psh->cmdnleft <= 0) {
            char *p = ps->cmd + len - 4;
            p[0] = '.';
            p[1] = '.';
            p[2] = '.';
            p[3] = 0;
      } else
            *psh->cmdnextc = '\0';
      TRACE((psh, "commandtext: ps->cmd %x, end %x, left %d\n\t\"%s\"\n",
            ps->cmd, psh->cmdnextc, psh->cmdnleft, ps->cmd));
}


STATIC void
cmdtxt(shinstance *psh, union node *n)
{
      union node *np;
      struct nodelist *lp;
      const char *p;
      int i;
      char s[2];

      if (n == NULL || psh->cmdnleft <= 0)
            return;
      switch (n->type) {
      case NSEMI:
            cmdtxt(psh, n->nbinary.ch1);
            cmdputs(psh, "; ");
            cmdtxt(psh, n->nbinary.ch2);
            break;
      case NAND:
            cmdtxt(psh, n->nbinary.ch1);
            cmdputs(psh, " && ");
            cmdtxt(psh, n->nbinary.ch2);
            break;
      case NOR:
            cmdtxt(psh, n->nbinary.ch1);
            cmdputs(psh, " || ");
            cmdtxt(psh, n->nbinary.ch2);
            break;
      case NPIPE:
            for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
                  cmdtxt(psh, lp->n);
                  if (lp->next)
                        cmdputs(psh, " | ");
            }
            break;
      case NSUBSHELL:
            cmdputs(psh, "(");
            cmdtxt(psh, n->nredir.n);
            cmdputs(psh, ")");
            break;
      case NREDIR:
      case NBACKGND:
            cmdtxt(psh, n->nredir.n);
            break;
      case NIF:
            cmdputs(psh, "if ");
            cmdtxt(psh, n->nif.test);
            cmdputs(psh, "; then ");
            cmdtxt(psh, n->nif.ifpart);
            if (n->nif.elsepart) {
                  cmdputs(psh, "; else ");
                  cmdtxt(psh, n->nif.elsepart);
            }
            cmdputs(psh, "; fi");
            break;
      case NWHILE:
            cmdputs(psh, "while ");
            goto until;
      case NUNTIL:
            cmdputs(psh, "until ");
until:
            cmdtxt(psh, n->nbinary.ch1);
            cmdputs(psh, "; do ");
            cmdtxt(psh, n->nbinary.ch2);
            cmdputs(psh, "; done");
            break;
      case NFOR:
            cmdputs(psh, "for ");
            cmdputs(psh, n->nfor.var);
            cmdputs(psh, " in ");
            cmdlist(psh, n->nfor.args, 1);
            cmdputs(psh, "; do ");
            cmdtxt(psh, n->nfor.body);
            cmdputs(psh, "; done");
            break;
      case NCASE:
            cmdputs(psh, "case ");
            cmdputs(psh, n->ncase.expr->narg.text);
            cmdputs(psh, " in ");
            for (np = n->ncase.cases; np; np = np->nclist.next) {
                  cmdtxt(psh, np->nclist.pattern);
                  cmdputs(psh, ") ");
                  cmdtxt(psh, np->nclist.body);
                  cmdputs(psh, ";; ");
            }
            cmdputs(psh, "esac");
            break;
      case NDEFUN:
            cmdputs(psh, n->narg.text);
            cmdputs(psh, "() { ... }");
            break;
      case NCMD:
            cmdlist(psh, n->ncmd.args, 1);
            cmdlist(psh, n->ncmd.redirect, 0);
            break;
      case NARG:
            cmdputs(psh, n->narg.text);
            break;
      case NTO:
            p = ">";  i = 1;  goto redir;
      case NCLOBBER:
            p = ">|";  i = 1;  goto redir;
      case NAPPEND:
            p = ">>";  i = 1;  goto redir;
      case NTOFD:
            p = ">&";  i = 1;  goto redir;
      case NFROM:
            p = "<";  i = 0;  goto redir;
      case NFROMFD:
            p = "<&";  i = 0;  goto redir;
      case NFROMTO:
            p = "<>";  i = 0;  goto redir;
redir:
            if (n->nfile.fd != i) {
                  s[0] = n->nfile.fd + '0';
                  s[1] = '\0';
                  cmdputs(psh, s);
            }
            cmdputs(psh, p);
            if (n->type == NTOFD || n->type == NFROMFD) {
                  s[0] = n->ndup.dupfd + '0';
                  s[1] = '\0';
                  cmdputs(psh, s);
            } else {
                  cmdtxt(psh, n->nfile.fname);
            }
            break;
      case NHERE:
      case NXHERE:
            cmdputs(psh, "<<...");
            break;
      default:
            cmdputs(psh, "???");
            break;
      }
}

STATIC void
cmdlist(shinstance *psh, union node *np, int sep)
{
      for (; np; np = np->narg.next) {
            if (!sep)
                  cmdputs(psh, " ");
            cmdtxt(psh, np);
            if (sep && np->narg.next)
                  cmdputs(psh, " ");
      }
}


STATIC void
cmdputs(shinstance *psh, const char *s)
{
      const char *p, *str = 0;
      char c, cc[2] = " ";
      char *nextc;
      int nleft;
      int subtype = 0;
      int quoted = 0;
      static char vstype[16][4] = { "", "}", "-", "+", "?", "=",
                              "#", "##", "%", "%%" };

      p = s;
      nextc = psh->cmdnextc;
      nleft = psh->cmdnleft;
      while (nleft > 0 && (c = *p++) != 0) {
            switch (c) {
            case CTLESC:
                  c = *p++;
                  break;
            case CTLVAR:
                  subtype = *p++;
                  if ((subtype & VSTYPE) == VSLENGTH)
                        str = "${#";
                  else
                        str = "${";
                  if (!(subtype & VSQUOTE) != !(quoted & 1)) {
                        quoted ^= 1;
                        c = '"';
                  } else
                        c = *str++;
                  break;
            case CTLENDVAR:
                  if (quoted & 1) {
                        c = '"';
                        str = "}";
                  } else
                        c = '}';
                  quoted >>= 1;
                  subtype = 0;
                  break;
            case CTLBACKQ:
                  c = '$';
                  str = "(...)";
                  break;
            case CTLBACKQ+CTLQUOTE:
                  c = '"';
                  str = "$(...)\"";
                  break;
            case CTLARI:
                  c = '$';
                  str = "((";
                  break;
            case CTLENDARI:
                  c = ')';
                  str = ")";
                  break;
            case CTLQUOTEMARK:
                  quoted ^= 1;
                  c = '"';
                  break;
            case '=':
                  if (subtype == 0)
                        break;
                  str = vstype[subtype & VSTYPE];
                  if (subtype & VSNUL)
                        c = ':';
                  else
                        c = *str++;
                  if (c != '}')
                        quoted <<= 1;
                  break;
            case '\'':
            case '\\':
            case '"':
            case '$':
                  /* These can only happen inside quotes */
                  cc[0] = c;
                  str = cc;
                  c = '\\';
                  break;
            default:
                  break;
            }
            do {
                  *nextc++ = c;
            } while (--nleft > 0 && str && (c = *str++));
            str = 0;
      }
      if ((quoted & 1) && nleft) {
            *nextc++ = '"';
            nleft--;
      }
      psh->cmdnleft = nleft;
      psh->cmdnextc = nextc;
}

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