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xec.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*                  Copyright (c) 1982-2005 AT&T Corp.                  *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                            by AT&T Corp.                             *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                  David Korn <dgk@research.att.com>                   *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * UNIX shell parse tree executer
 *
 *   David Korn
 *   AT&T Labs
 *
 */

#include    "defs.h"
#include    <fcin.h>
#include    "variables.h"
#include    "path.h"
#include    "name.h"
#include    "io.h"
#include    "shnodes.h"
#include    "jobs.h"
#include    "test.h"
#include    "builtins.h"
#include    "FEATURE/time"
#include    "FEATURE/externs"
#include    "FEATURE/locale"
#include    "streval.h"

#if !_std_malloc
#   include <vmalloc.h>
#endif

#define SH_NTFORK SH_TIMING

#if _lib_nice
    extern int    nice(int);
#endif /* _lib_nice */
#if !_lib_spawnveg
#   define spawnveg(a,b,c,d)    spawnve(a,b,c)
#endif /* !_lib_spawnveg */
#if SHOPT_SPAWN
    static pid_t sh_ntfork(const Shnode_t*,char*[],int*,int);
#endif /* SHOPT_SPAWN */

static void sh_funct(Namval_t*, int, char*[], struct argnod*,int);
static int  trim_eq(const char*, const char*);
static char *word_trim(struct argnod*, int);
static void coproc_init(int pipes[]);

static void *timeout;
static char pipejob;

struct funenv
{
      Namval_t    *node;
      struct argnod     *env;
};

/* ======== command execution ========*/

/*
 * print time <t> in h:m:s format with precision <p>
 */
static void     l_time(Sfio_t *outfile,register clock_t t,int p)
{
      register int  min, sec, frac;
      register int hr;
      if(p)
      {
            frac = t%sh.lim.clk_tck;
            frac = (frac*100)/sh.lim.clk_tck;
      }
      t /= sh.lim.clk_tck;
      sec = t%60;
      t /= 60;
      min = t%60;
      if(hr=t/60)
            sfprintf(outfile,"%dh",hr);
      if(p)
            sfprintf(outfile,"%dm%d%c%0*ds",min,sec,GETDECIMAL(0),p,frac);
      else
            sfprintf(outfile,"%dm%ds",min,sec);
}

static int p_time(Sfio_t *out, const char *format, clock_t *tm)
{
      int c,p,l,n,offset = staktell();
      const char *first;
      double d;
      for(first=format ; c= *format; format++)
      {
            if(c!='%')
                  continue;
            stakwrite(first, format-first);
            n = l = 0;
            p = 3;
            if((c= *++format) == '%')
            {
                  first = format;
                  continue;
            }
            if(c>='0' && c <='9')
            {
                  p = (c>'3')?3:(c-'0');
                  c = *++format;
            }
            else if(c=='P')
            {
                  if(d=tm[0])
                        d = 100.*(((double)(tm[1]+tm[2]))/d);
                  p = 2;
                  goto skip;
            }
            if(c=='l')
            {
                  l = 1;
                  c = *++format;
            }
            if(c=='U')
                  n = 1;
            else if(c=='S')
                  n = 2;
            else if(c!='R')
            {
                  stakseek(offset);
                  errormsg(SH_DICT,ERROR_exit(0),e_badtformat,c);
                  return(0);
            }
            d = (double)tm[n]/60;
      skip:
            if(l)
                  l_time(stkstd, tm[n], p);
            else
                  sfprintf(stkstd,"%.*f",p, d);
            first = format+1;
      }
      if(format>first)
            stakwrite(first, format-first);
      stakputc('\n');
      n = staktell()-offset;
      sfwrite(out,stakptr(offset),n);
      stakseek(offset);
      return(n);
}

#if SHOPT_OPTIMIZE
/*
 * clear argument pointers that point into the stack
 */
static void p_arg(struct argnod*,int);
static void p_switch(struct regnod*);
static void p_comarg(register struct comnod *com)
{
      Namval_t *np;
      p_arg(com->comset,ARG_ASSIGN);
      if(com->comarg && (com->comtyp&COMSCAN))
            p_arg(com->comarg,0);
      if(com->comstate  && (np=com->comnamp))
      {
            /* call builtin to cleanup state */
            Nambltin_t bdata; 
            bdata.shp = &sh;
            bdata.np = com->comnamq;
            bdata.ptr =nv_context(np);
            bdata.data = com->comstate;
            bdata.flags = SH_END_OPTIM;
            (*funptr(np))(0,(char**)0, &bdata);
      }
      com->comstate = 0;
}

extern void sh_optclear(Shell_t*, void*);

static void sh_tclear(register Shnode_t *t)
{
      if(!t)
            return;
      switch(t->tre.tretyp&COMMSK)
      {
            case TTIME:
            case TPAR:
                  sh_tclear(t->par.partre); 
                  return;
            case TCOM:
                  p_comarg((struct comnod*)t);
                  return;
            case TSETIO:
            case TFORK:
                  sh_tclear(t->fork.forktre);
                  return;
            case TIF:
                  sh_tclear(t->if_.iftre);
                  sh_tclear(t->if_.thtre);
                  sh_tclear(t->if_.eltre);
                  return;
            case TWH:
                  if(t->wh.whinc)
                        sh_tclear((Shnode_t*)(t->wh.whinc));
                  sh_tclear(t->wh.whtre);
                  sh_tclear(t->wh.dotre);
                  return;
            case TLST:
            case TAND:
            case TORF:
            case TFIL:
                  sh_tclear(t->lst.lstlef);
                  sh_tclear(t->lst.lstrit);
                  return;
            case TARITH:
                  p_arg(t->ar.arexpr,ARG_ARITH);
                  return;
            case TFOR:
                  sh_tclear(t->for_.fortre);
                  sh_tclear((Shnode_t*)t->for_.forlst);
                  return;
            case TSW:
                  p_arg(t->sw.swarg,0);
                  p_switch(t->sw.swlst);
                  return;
            case TFUN:
                  sh_tclear(t->funct.functtre);
                  sh_tclear((Shnode_t*)t->funct.functargs);
                  return;
            case TTST:
                  if((t->tre.tretyp&TPAREN)==TPAREN)
                        sh_tclear(t->lst.lstlef); 
                  else
                  {
                        p_arg(&(t->lst.lstlef->arg),0);
                        if(t->tre.tretyp&TBINARY)
                              p_arg(&(t->lst.lstrit->arg),0);
                  }
                  return;
      }
      return;
}

static void p_arg(register struct argnod *arg,int flag)
{
      while(arg)
      {
            if(strlen(arg->argval) || (flag==0 && (arg->argflag&~ARG_APPEND)))
                  arg->argchn.ap = 0;
            else
                  sh_tclear(((struct fornod*)arg->argchn.ap)->fortre);
            arg = arg->argnxt.ap;
      }
}

static void p_switch(register struct regnod *reg)
{
      while(reg)
      {
            p_arg(reg->regptr,0);
            sh_tclear(reg->regcom);
            reg = reg->regnxt;
      }
}
#   define OPTIMIZE_FLAG      (ARG_OPTIMIZE)
#   define OPTIMIZE           (flags&OPTIMIZE_FLAG)
#else
#   define OPTIMIZE_FLAG      (0)
#   define OPTIMIZE           (0)
#   define sh_tclear(x)
#endif /* SHOPT_OPTIMIZE */

static void out_pattern(Sfio_t *iop, register const char *cp, int n)
{
      register int c;
      do
      {
            switch(c= *cp)
            {
                case 0:
                  if(n<0)
                        return;
                  c = n;
                  break;
                case '\n':
                  sfputr(iop,"$'\\n",'\'');
                  continue;
                case '\\':
                  if(c= *cp)
                        cp++;
                case ' ':
                case '<': case '>': case ';':
                case '$': case '`': case '\t':
                  sfputc(iop,'\\');
            }
            sfputc(iop,c);
      }
      while(*cp++);
}

static void out_string(Sfio_t *iop, register const char *cp, int c, int quoted)
{
      if(quoted)
      {
            int n = staktell();
            cp = sh_fmtq(cp);
            if(iop==stkstd && cp==stkptr(stkstd,n))
            {
                  *stkptr(stkstd,stktell(stkstd)-1) = c;
                  return;
            }
      }
      sfputr(iop,cp,c);
}

struct Level
{
      Namfun_t    hdr;
      short       maxlevel;
};

/*
 * this is for a debugger but it hasn't been tested yet
 * if a debug script sets .sh.level it should set up the scope
 *  as if you were executing in that level
 */ 
static void put_level(Namval_t* np,const char *val,int flags,Namfun_t *fp)
{
      Shscope_t   *sp;
      struct Level *lp = (struct Level*)fp;
      short level, oldlevel = (short)nv_getnum(np);
      nv_putv(np,val,flags,fp);
      level = nv_getnum(np);
      if(level<0 || level > lp->maxlevel)
      {
            nv_putv(np, (char*)&oldlevel, flags, fp);
            /* perhaps this should be an error */
            return;
      }
      if(level==oldlevel)
            return;
      sp = sh_getscope(level,SEEK_SET);
      sh_setscope(sp);
      error_info.line = sp->lineno;
      nv_putval(SH_PATHNAMENOD, sh.st.filename ,NV_NOFREE);
}

static const Namdisc_t level_disc = {  0, put_level };

/*
 * write the current common on the stack and make it available as .sh.command
 */
int sh_debug(const char *trap, const char *name, const char *subscript, char *const argv[], int flags)
{
      struct sh_scoped savst;
      Shscope_t   *sp, *topmost;
      Namval_t    *np = SH_COMMANDNOD;
      struct Level      lev;
      char        *sav = stakptr(0);
      int         n=4, offset=staktell();
      const char  *cp = "+=( ";
      Sfio_t            *iop = stkstd;
      short       level;
      if(name)
      {
            sfputr(iop,name,-1);
            if(subscript)
            {
                  sfputc(iop,'[');
                  out_string(iop,subscript,']',1);
            }
            if(!(flags&ARG_APPEND))
                  cp+=1, n-=1;
            if(!(flags&ARG_ASSIGN))
                  n -= 2;
            sfwrite(iop,cp,n);
      }
      if(!(flags&ARG_RAW))
            out_string(iop, *argv++,' ', 0);
      n = (flags&ARG_ARITH);
      while(cp = *argv++)
      {
            if((flags&ARG_EXP) && argv[1]==0)
                  out_pattern(iop, cp,' ');
            else
                  out_string(iop, cp,' ',n?0: (flags&(ARG_RAW|ARG_NOGLOB))||*argv);
      }
      if(flags&ARG_ASSIGN)
            sfputc(iop,')');
      else if(iop==stkstd)
            *stakptr(staktell()-1) = 0;
      np->nvalue.cp = stakfreeze(1);
      sh.st.lineno = error_info.line;
      /* now setup .sh.level variable */
      topmost = sh_getscope(0,SEEK_END);
      for(level=0, sp=topmost; sp; sp=sp->par_scope)
            level++;
      memset((void*)&lev,0,sizeof(lev));
      lev.hdr.disc = &level_disc;
      lev.maxlevel = --level;
      nv_unset(SH_LEVELNOD);
      nv_onattr(SH_LEVELNOD,NV_INTEGER|NV_SHORT|NV_NOFREE);
      nv_putval(SH_LEVELNOD,(char*)&level,NV_INTEGER|NV_SHORT);
      nv_disc(SH_LEVELNOD,&lev.hdr,NV_FIRST);
      savst = sh.st;
      sh.st.trap[SH_DEBUGTRAP] = 0;
      n = sh_trap(trap,0);
      np->nvalue.cp = 0;
      nv_putval(SH_LEVELNOD,(char*)&level,NV_INTEGER|NV_SHORT);
      nv_disc(SH_LEVELNOD,&lev.hdr,NV_POP);
      nv_unset(SH_LEVELNOD);
      nv_putval(SH_PATHNAMENOD, sh.st.filename ,NV_NOFREE);
      sh.st = savst;
      if(sav != stakptr(0))
            stakset(sav,0);
      else
            stakseek(offset);
      return(n);
}

/*
 * Given stream <iop> compile and execute
 */
int sh_eval(register Sfio_t *iop, int mode)
{
      register Shnode_t *t;
      Shell_t  *shp = sh_getinterp();
      struct slnod *saveslp = shp->st.staklist;
      int jmpval;
      struct checkpt *pp = (struct checkpt*)shp->jmplist;
      struct checkpt buff;
      static Sfio_t *io_save;
      io_save = iop; /* preserve correct value across longjmp */
      sh_pushcontext(&buff,SH_JMPEVAL);
      buff.olist = pp->olist;
      jmpval = sigsetjmp(buff.buff,0);
      if(jmpval==0)
      {
            t = (Shnode_t*)sh_parse(shp,iop,SH_NL);
            sfclose(iop);
            io_save = 0;
            if(!sh_isoption(SH_VERBOSE))
                  sh_offstate(SH_VERBOSE);
            if(mode && shp->hist_ptr)
            {
                  hist_flush(shp->hist_ptr);
                  mode = sh_state(SH_INTERACTIVE);
            }
            sh_exec(t,sh_isstate(SH_ERREXIT)|mode);
      }
      sh_popcontext(&buff);
      if(io_save)
            sfclose(io_save);
      sh_freeup();
      shp->st.staklist = saveslp;
      if(jmpval>SH_JMPEVAL)
            siglongjmp(*shp->jmplist,jmpval);
      return(sh.exitval);
}

#if SHOPT_FASTPIPE
static int pipe_exec(int pv[], Shnode_t *t, int errorflg)
{
      struct checkpt buff;
      register Shnode_t *tchild = t->fork.forktre;
      Namval_t *np;
      Sfio_t *iop;
      int jmpval,r;
      if((tchild->tre.tretyp&COMMSK)!=TCOM || !(np=(Namval_t*)(tchild->com.comnamp)))
      {
            sh_pipe(pv);
            return(sh_exec(t,errorflg));
      }
      pv[0] = sh.lim.open_max;
      sh.fdstatus[pv[0]] = IOREAD|IODUP|IOSEEK;
      pv[1] = sh.lim.open_max+1;
      sh.fdstatus[pv[1]] = IOWRITE|IOSEEK;
      iop = sftmp(IOBSIZE+1);
      sh.sftable[sh.lim.open_max+1] = iop;
      sh_pushcontext(&buff,SH_JMPIO);
      if(t->tre.tretyp&FPIN)
            sh_iosave(0,sh.topfd);
      sh_iosave(1,sh.topfd);
      jmpval = sigsetjmp(buff.buff,0);
      if(jmpval==0)
      {
            if(t->tre.tretyp&FPIN)
                  sh_iorenumber(sh.inpipe[0],0);
            sh_iorenumber(sh.lim.open_max+1,1);
            r = sh_exec(tchild,errorflg);
            if(sffileno(sfstdout)>=0)
                  pv[0] = sfsetfd(sfstdout,10);
            iop = sfswap(sfstdout,0);
      }
      sh_popcontext(&buff);
      sh.sftable[pv[0]] = iop;
      sh.fdstatus[pv[0]] = IOREAD|IODUP|IOSEEK;
      sfset(iop,SF_WRITE,0);
      sfseek(iop,0L,SEEK_SET);
      sh_iorestore(buff.topfd,jmpval);
      if(jmpval>SH_JMPIO)
            siglongjmp(*sh.jmplist,jmpval);
      return(r);
}
#endif /* SHOPT_FASTPIPE */

/*
 * returns 1 when option -<c> is specified
 */
static int checkopt(char *argv[], int c)
{
      char *cp;
      while(cp = *++argv)
      {
            if(*cp=='+')
                  continue;
            if(*cp!='-' || cp[1]=='-')
                  break;
            if(strchr(cp,c))
                  return(1);
      }
      return(0);
}

static void free_list(struct openlist *olist)
{
      struct openlist *item,*next;
      for(item=olist;item;item=next)
      {
            next = item->next;
            free((void*)item);
      }
}

int sh_exec(register const Shnode_t *t, int flags)
{
      sh_sigcheck();
      if(t && !sh.st.execbrk && !sh_isoption(SH_NOEXEC))
      {
            register int      type = flags;
            register char     *com0 = 0;
            int         errorflg = (type&sh_state(SH_ERREXIT))|OPTIMIZE;
            int         execflg = (type&sh_state(SH_NOFORK));
            int         mainloop = (type&sh_state(SH_INTERACTIVE));
#if SHOPT_SPAWN
            int         ntflag = (type&sh_state(SH_NTFORK));
#endif
            int         topfd = sh.topfd;
            char        *sav=stakptr(0);
            char        *cp=0, **com=0;
            int         argn;
            int         skipexitset = 0;
            int         was_interactive = 0;
            int         was_errexit = sh_isstate(SH_ERREXIT);
            int         was_monitor = sh_isstate(SH_MONITOR);
            int         echeck = 0;
            if(flags&sh_state(SH_INTERACTIVE))
            {
                  pipejob = 0;
                  job.curpgid = 0;
                  flags &= ~sh_state(SH_INTERACTIVE);
            }
            sh_offstate(SH_ERREXIT);
            sh_offstate(SH_DEFPATH);
            if(was_errexit&flags)
                  sh_onstate(SH_ERREXIT);
            if(was_monitor&flags)
                  sh_onstate(SH_MONITOR);
            type = t->tre.tretyp;
            if(!sh.intrap)
                  sh.oldexit=sh.exitval;
            sh.exitval=0;
            sh.lastsig = 0;
            sh.lastpath = 0;
            switch(type&COMMSK)
            {
                case TCOM:
                {
                  register struct argnod  *argp;
                  char        *trap;
                  Namval_t    *np, *nq;
                  struct ionod      *io;
                  int         command=0;
                  error_info.line = t->com.comline-sh.st.firstline;
                  com = sh_argbuild(&argn,&(t->com),OPTIMIZE);
                  echeck = 1;
                  if(t->tre.tretyp&COMSCAN)
                  {
                        argp = t->com.comarg;
                        if(argp && *com && !(argp->argflag&ARG_RAW))
                              sh_sigcheck();
                  }
                  np = (Namval_t*)(t->com.comnamp);
                  nq = (Namval_t*)(t->com.comnamq);
                  com0 = com[0];
                  sh.xargexit = 0;
                  while(np==SYSCOMMAND)
                  {
                        register int n = b_command(0,com,&sh);
                        if(n==0)
                              break;
                        command += n;
                        np = 0;
                        if(!(com0= *(com+=n)))
                              break;
                        np = nv_bfsearch(com0, sh.bltin_tree, &nq, &cp); 
                  }
                  if(sh.xargexit)
                  {
                        sh.xargmin -= command;
                        sh.xargmax -= command;
                  }
                  else
                        sh.xargmin = 0;
                  argn -= command;
                  if(!command && np && is_abuiltin(np))
                        np = dtsearch(sh.fun_tree,np);
                  if(com0 && !np && !strchr(com0,'/'))
                  {
                        Dt_t *root = command?sh.bltin_tree:sh.fun_tree;
                        np = nv_bfsearch(com0, root, &nq, &cp); 
#if SHOPT_NAMESPACE
                        if(sh.namespace && !nq && !cp)
                        {
                              int offset = staktell();
                              stakputs(nv_name(sh.namespace));
                              stakputc('.');
                              stakputs(com0);
                              stakseek(offset);
                              np = nv_bfsearch(stakptr(offset), root, &nq, &cp); 
                        }
#endif /* SHOPT_NAMESPACE */
                  }
                  io = t->tre.treio;
                  if(sh.envlist = argp = t->com.comset)
                  {
                        if(argn==0 || (np && !command && nv_isattr(np,BLT_SPC)))
                        {
                              register int flgs=NV_VARNAME|NV_ASSIGN;
#if SHOPT_BASH
                              if(np==SYSLOCAL)
                              {
                                    if(!nv_getval(SH_FUNNAMENOD))
                                          errormsg(SH_DICT,ERROR_exit(1),"%s: can only be used in a function",com0);
                                    if(!sh.st.var_local)
                                    {
                                          nv_scope((struct argnod*)0);
                                          sh.st.var_local = sh.var_tree;
                                    }
                  
                              }
                              if(np==SYSTYPESET || np==SYSLOCAL)
#else
                              if(np==SYSTYPESET)
#endif
                              {
                                    if(checkopt(com,'n'))
                                          flgs |= NV_NOREF;
                                    if(sh.fn_depth || np==SYSLOCAL)
                                          flgs |= NV_NOSCOPE;
                              }
                              else if(np)
                                    flgs = NV_IDENT|NV_ASSIGN;
#if 0
                              if(OPTIMIZE)
                                    flgs |= NV_TAGGED;
#endif
                              nv_setlist(argp,flgs);
                              argp = NULL;
                        }
                  }
                  sh.last_table = 0;
                  if((io||argn))
                  {
                        static char *argv[1];
                        if(argn==0)
                        {
                              /* fake 'true' built-in */
                              argn=1;
                              np = SYSTRUE;
                              *argv = nv_name(np);
                              com = argv;
                        }
                        /* set +x doesn't echo */
                        else if((np!=SYSSET) && sh_isoption(SH_XTRACE))
                              sh_trace(com-command,1);
                        if(trap=sh.st.trap[SH_DEBUGTRAP])
                              sh_debug(trap,(char*)0, (char*)0, com, ARG_RAW);
                        if(io)
                              sfsync(sh.outpool);
                        sh.lastpath = 0;
                        if(!np  && !strchr(com0,'/'))
                        {
#ifdef PATH_BFPATH
                              if(path_search(com0,NIL(Pathcomp_t*),1))
                                    np=nv_search(com0,sh.fun_tree,0);
                              else
                              {
                                    if((np=nv_search(com0,sh.track_tree,0)) && !nv_isattr(np,NV_NOALIAS) && np->nvalue.cp)
                                          np=nv_search(nv_getval(np),sh.bltin_tree,0);
                                    else
                                          np = 0;
                              }
#else
                              if(path_search(com0,NIL(char*),1))
                                    np=nv_search(com0,sh.fun_tree,0);
                              if(sh.lastpath)
                                    np=nv_search(sh.lastpath,sh.bltin_tree,0);
#endif
                        }
                        /* check for builtins */
                        if(np && is_abuiltin(np))
                        {
                              Nambltin_t bdata; 
                              void *context;
                              int scope=0, jmpval, save_prompt,share;
                              struct checkpt buff;
                              unsigned long was_vi=0, was_emacs=0, was_gmacs=0;
                              if(strchr(nv_name(np),'/'))
                              {
                                    /*
                                     * disable editors for built-in
                                     * versions of commands on PATH
                                     */
                                    was_vi = sh_isoption(SH_VI);
                                    was_emacs = sh_isoption(SH_EMACS);
                                    was_gmacs = sh_isoption(SH_GMACS);
                                    sh_offoption(SH_VI);
                                    sh_offoption(SH_EMACS);
                                    sh_offoption(SH_GMACS);
                              }
                              sh_pushcontext(&buff,SH_JMPCMD);
                              jmpval = sigsetjmp(buff.buff,1);
                              if(jmpval == 0)
                              {
                                    if(!(nv_isattr(np,BLT_ENV)))
                                          error_info.flags |= ERROR_SILENT;
                                    errorpush(&buff.err,0);
                                    if(io)
                                    {
                                          struct openlist *item;
                                          if(np==SYSLOGIN)
                                                type=1;
                                          else if(np==SYSEXEC)
                                                type=1+!com[1];
                                          else
                                                type = (execflg && !sh.subshell && !sh.st.trapcom[0]);
                                          sh_redirect(io,type);
                                          for(item=buff.olist;item;item=item->next)
                                                item->strm=0;
                                    }
                                    if(!(nv_isattr(np,BLT_ENV)))
                                    {
                                          share = sfset(sfstdin,SF_SHARE,0);
                                          sh_onstate(SH_STOPOK);
                                          sfpool(sfstderr,NIL(Sfio_t*),SF_WRITE);
                                          save_prompt = sh.nextprompt;
                                          sh.nextprompt = 0;
                                    }
                                    if(argp)
                                    {
                                          scope++;
                                          nv_scope(argp);
                                    }
                                    opt_info.index = opt_info.offset = 0;
                                    opt_info.disc = 0;
                                    error_info.id = *com;
                                    sh.exitval = 0;
                                    if(!(context=nv_context(np)))
                                          context = (void*)&sh;
                                    sh.bltinfun = funptr(np);
                                    if(nv_isattr(np,NV_BLTINOPT))
                                    {
                                          bdata.shp = &sh;
                                          bdata.np = nq;
                                          bdata.ptr = context;
                                          bdata.data = t->com.comstate;
                                          bdata.flags = (OPTIMIZE!=0);
                                          context = (void*)&bdata;
                                    }
                                    sh.exitval = (*sh.bltinfun)(argn,com,context);
                                    if(error_info.flags&ERROR_INTERACTIVE)
                                          tty_check(ERRIO);
                                    if(nv_isattr(np,NV_BLTINOPT))
                                          ((Shnode_t*)t)->com.comstate = bdata.data;
                                    if(!nv_isattr(np,BLT_EXIT) && sh.exitval!=SH_RUNPROG)
                                          sh.exitval &= SH_EXITMASK;
                              }
                              else
                              {
                                    struct openlist *item;
                                    for(item=buff.olist;item;item=item->next)
                                    {
                                          if(item->strm)
                                          {
                                                sfclrlock(item->strm);
                                                sfclose(item->strm);
                                          }
                                    }
                                    /* failure on special built-ins fatal */
                                    if(jmpval<=SH_JMPCMD  && (!nv_isattr(np,BLT_SPC) || command))
                                          jmpval=0;
                              }
                              if(!(nv_isattr(np,BLT_ENV)))
                              {
                                    sh_offstate(SH_STOPOK);
                                    if(share&SF_SHARE)
                                          sfset(sfstdin,SF_PUBLIC|SF_SHARE,1);
                                    sfpool(sfstderr,sh.outpool,SF_WRITE);
                                    sfpool(sfstdin,NIL(Sfio_t*),SF_WRITE);
                                    sh.nextprompt = save_prompt;
                              }
                              sh_popcontext(&buff);
                              errorpop(&buff.err);
                              error_info.flags &= ~ERROR_SILENT;
                              sh.bltinfun = 0;
                              if(buff.olist)
                                    free_list(buff.olist);
                              if(was_vi)
                                    sh_onoption(SH_VI);
                              else if(was_emacs)
                                    sh_onoption(SH_EMACS);
                              else if(was_gmacs)
                                    sh_onoption(SH_GMACS);
                              if(scope)
                                    nv_unscope();
                              /* don't restore for subshell exec */
                              if(io && !sh.subshell || np!=SYSEXEC)
                                    sh_iorestore(buff.topfd,jmpval);
                              if(jmpval)
                                    siglongjmp(*sh.jmplist,jmpval);
                              if(sh.exitval >=0)
                                    goto setexit;
                              np = 0;
                              type=0;
                        }
                        /* check for functions */
                        if(!command && np && nv_isattr(np,NV_FUNCTION))
                        {
                              int indx,jmpval=0;
                              struct checkpt buff;
                              register struct slnod *slp;
                              if(!np->nvalue.ip)
                              {
#ifdef PATH_BFPATH
                                    indx = path_search(com0,NIL(Pathcomp_t*),0);
#else
                                    indx = path_search(com0,NIL(char*),0);
#endif
                                    if(indx==1)
                                          np = nv_search(com0,sh.fun_tree,HASH_NOSCOPE);
                                    if(!np->nvalue.ip)
                                    {
                                          if(indx==1)
                                          {
                                                errormsg(SH_DICT,ERROR_exit(0),e_defined,com0);
                                                sh.exitval = ERROR_NOEXEC;
                                          }
                                          else
                                          {
                                                errormsg(SH_DICT,ERROR_exit(0),e_found,"function");
                                                sh.exitval = ERROR_NOENT;
                                          }
                                          goto setexit;
                                    }
                              }
                              /* increase refcnt for unset */
                              slp = (struct slnod*)np->nvenv;
                              sh_funstaks(slp->slchild,1);
                              staklink(slp->slptr);
                              if(nq)
                              {
                                    nv_putval(SH_NAMENOD, nv_name(nq), NV_NOFREE);
                                    if(nv_arrayptr(nq))
                                          nv_putval(SH_SUBSCRNOD,nv_getsub(nq),NV_NOFREE);
                              }
                              if(io)
                              {
                                    indx = sh.topfd;
                                    sh_pushcontext(&buff,SH_JMPCMD);
                                    jmpval = sigsetjmp(buff.buff,0);
                              }
                              if(jmpval == 0)
                              {
                                    if(io)
                                          indx = sh_redirect(io,execflg);
                                    sh_funct(np,argn,com,t->com.comset,(flags&~OPTIMIZE_FLAG));
                              }
                              if(io)
                              {
                                    if(buff.olist)
                                          free_list(buff.olist);
                                    sh_popcontext(&buff);
                                    sh_iorestore(indx,jmpval);
                              }
                              if(nq)
                              {
                                    nv_unset(SH_NAMENOD);
                                    nv_unset(SH_SUBSCRNOD);
                              }
                              sh_funstaks(slp->slchild,-1);
                              stakdelete(slp->slptr);
                              if(jmpval > SH_JMPFUN)
                                    siglongjmp(*sh.jmplist,jmpval);
                              goto setexit;
                        }
                  }
                  else if(!io)
                  {
                  setexit:
                        exitset();
                        break;
                  }
                }
                case TFORK:
                {
                  register pid_t parent;
                  int no_fork,jobid;
                  int pipes[2];
                  no_fork = (execflg && !(type&(FAMP|FPOU)) &&
                        !sh.subshell && !sh.st.trapcom[0] && 
                        !sh.st.trap[SH_ERRTRAP] && sh.fn_depth==0);
                  if(sh.subshell)
                        sh_subtmpfile();
                  if(sh_isstate(SH_PROFILE) || sh.dot_depth)
                  {
                        /* disable foreground job monitor */
                        if(!(type&FAMP))
                              sh_offstate(SH_MONITOR);
#if SHOPT_DEVFD
                        else if(!(type&FINT))
                              sh_offstate(SH_MONITOR);
#endif /* SHOPT_DEVFD */
                  }
                  if(no_fork)
                        job.parent=parent=0;
                  else
                  {
                        if(type&FCOOP)
                              coproc_init(pipes);
                        nv_getval(RANDNOD);
#ifdef SHOPT_AMP
                        if((type&(FAMP|FINT)) == (FAMP|FINT))
                              parent = sh_ntfork(t,com,&jobid,ntflag);
                        else
                              parent = sh_fork(type,&jobid);
                        if(parent<0)
                              break;
#else
#if SHOPT_SPAWN
#   ifdef _lib_fork
                        if(com)
                              parent = sh_ntfork(t,com,&jobid,ntflag);
                        else
                              parent = sh_fork(type,&jobid);
#   else
                        if((parent = sh_ntfork(t,com,&jobid,ntflag))<=0)
                              break;
#   endif /* _lib_fork */
                        if(parent<0)
                              break;
#else
                        parent = sh_fork(type,&jobid);
#endif /* SHOPT_SPAWN */
#endif
                  }
                  if(job.parent=parent)
                  /* This is the parent branch of fork
                   * It may or may not wait for the child
                   */
                  {
                        if(type&FPCL)
                              sh_close(sh.inpipe[0]);
                        if(type&(FCOOP|FAMP))
                              sh.bckpid = parent;
                        if(!(type&(FAMP|FPOU)))
                        {
                              if(sh.topfd > topfd)
                                    sh_iorestore(topfd,0);
                              job_wait(parent);
                        }
                        if(type&FAMP)
                        {
                              if(sh_isstate(SH_PROFILE) || sh_isstate(SH_INTERACTIVE))
                              {
                                    /* print job number */
#ifdef JOBS
                                    sfprintf(sfstderr,"[%d]\t%d\n",jobid,parent);
#else
                                    sfprintf(sfstderr,"%d\n",parent);
#endif /* JOBS */
                              }
                        }
                        break;
                  }
                  else
                  /*
                   * this is the FORKED branch (child) of execute
                   */
                  {
                        int jmpval;
                        struct checkpt buff;
                        if(no_fork)
                              sh_sigreset(2);
                        sh_pushcontext(&buff,SH_JMPEXIT);
                        jmpval = sigsetjmp(buff.buff,0);
                        if(jmpval)
                              goto done;
                        if((type&FINT) && !sh_isstate(SH_MONITOR))
                        {
                              /* default std input for & */
                              signal(SIGINT,SIG_IGN);
                              signal(SIGQUIT,SIG_IGN);
                              if(!sh.st.ioset)
                              {
                                    if(sh_close(0)>=0)
                                          sh_chkopen(e_devnull);
                              }
                        }
                        sh_offstate(SH_MONITOR);
                        /* pipe in or out */
#ifdef _lib_nice
                        if((type&FAMP) && sh_isoption(SH_BGNICE))
                              nice(4);
#endif /* _lib_nice */
                        if(type&FPIN)
                        {
                              sh_iorenumber(sh.inpipe[0],0);
                              if(!(type&FPOU) || (type&FCOOP))
                                    sh_close(sh.inpipe[1]);
                        }
                        if(type&FPOU)
                        {
                              sh_iorenumber(sh.outpipe[1],1);
                              sh_pclose(sh.outpipe);
                        }
                        if((type&COMMSK)!=TCOM)
                              error_info.line = t->fork.forkline-sh.st.firstline;
                        sh_redirect(t->tre.treio,1);
                        if(sh.topfd)
                              sh_iounsave();
                        if((type&COMMSK)!=TCOM)
                        {
                              /* don't clear job table for out
                                 pipes so that jobs comand can
                                 be used in a pipeline
                               */
                              if(!no_fork && !(type&FPOU))
                                    job_clear();
                              sh_exec(t->fork.forktre,flags|sh_state(SH_NOFORK));
                        }
                        else if(com0)
                        {
                              sh_offoption(SH_ERREXIT);
                              sh_freeup();
                              path_exec(com0,com,t->com.comset);
                        }
                  done:
                        sh_popcontext(&buff);
                        if(jmpval>SH_JMPEXIT)
                              siglongjmp(*sh.jmplist,jmpval);
                        sh_done(0);
                  }
                }

                case TSETIO:
                {
                /*
                 * don't create a new process, just
                 * save and restore io-streams
                 */
                  pid_t pid;
                  int jmpval, waitall;
                  struct checkpt buff;
                  if(sh.subshell)
                  {
                        flags &= ~sh_state(SH_NOFORK);
                        execflg = 0;
                  }
                  sh_pushcontext(&buff,SH_JMPIO);
                  if(type&FPIN)
                  {
                        was_interactive = sh_isstate(SH_INTERACTIVE);
                        sh_offstate(SH_INTERACTIVE);
                        if(!execflg)
                              sh_iosave(0,sh.topfd);
                        sh_iorenumber(sh.inpipe[0],0);
                        /*
                         * if read end of pipe is a simple command
                         * treat as non-sharable to improve performance
                         */
                        if((t->fork.forktre->tre.tretyp&COMMSK)==TCOM)
                              sfset(sfstdin,SF_PUBLIC|SF_SHARE,0);
                        waitall = job.waitall;
                        job.waitall = 0;
                        pid = job.parent;
                  }
                  else
                        error_info.line = t->fork.forkline-sh.st.firstline;
                  jmpval = sigsetjmp(buff.buff,0);
                  if(jmpval==0)
                  {
                        sh_redirect(t->fork.forkio,execflg);
                        sh_exec(t->fork.forktre,flags);
                  }
                  sh_popcontext(&buff);
                  sh_iorestore(buff.topfd,jmpval);
                  if(type&FPIN)
                  {
                        job.waitall = waitall;
                        type = sh.exitval;
                        if(!(type&SH_EXITSIG))
                        {
                              /* wait for remainder of pipline */
                              job_wait(waitall?pid:0);
                              if(type || !sh_isoption(SH_PIPEFAIL))
                                    sh.exitval = type;
                        }
                        sh.st.ioset = 0;
                  }
                  if(jmpval>SH_JMPIO)
                        siglongjmp(*sh.jmplist,jmpval);
                  break;
                }

                case TPAR:
                  echeck = 1;
                  flags &= ~OPTIMIZE_FLAG;
                  if(!sh.subshell && !sh.st.trapcom[0] && !sh.st.trap[SH_ERRTRAP] && (flags&sh_state(SH_NOFORK)))
                  {
                        int jmpval;
                        struct checkpt buff;
                        sh_pushcontext(&buff,SH_JMPEXIT);
                        jmpval = sigsetjmp(buff.buff,0);
                        if(jmpval==0)
                              sh_exec(t->par.partre,flags);
                        sh_popcontext(&buff);
                        if(jmpval > SH_JMPEXIT)
                              siglongjmp(*sh.jmplist,jmpval);
                        sh_done(0);
                  }
                  else
                        sh_subshell(t->par.partre,flags,0);
                  break;

                case TFIL:
                {
                /*
                 * This code sets up a pipe.
                 * All elements of the pipe are started by the parent.
                 * The last element executes in current environment
                 */
                  int   pvo[2];     /* old pipe for multi-stage */
                  int   pvn[2];     /* current set up pipe */
                  int   savepipe = pipejob;
                  pid_t savepgid = job.curpgid;
                  if(sh.subshell)
                        sh_subtmpfile();
                  sh.inpipe = pvo;
                  sh.outpipe = pvn;
                  pvo[1] = -1;
                  if(sh_isoption(SH_PIPEFAIL))
                        job.waitall = 1;
                  else
                        job.waitall |= !pipejob && sh_isstate(SH_MONITOR);
                  do
                  {
#if SHOPT_FASTPIPE
                        type = pipe_exec(pvn,t->lst.lstlef, errorflg);
#else
                        /* create the pipe */
                        sh_pipe(pvn);
                        /* execute out part of pipe no wait */
                        type = sh_exec(t->lst.lstlef, errorflg);
#endif /* SHOPT_FASTPIPE */
                        pipejob=1;
                        /* save the pipe stream-ids */
                        pvo[0] = pvn[0];
                        /* close out-part of pipe */
                        sh_close(pvn[1]);
                        /* pipeline all in one process group */
                        t = t->lst.lstrit;
                  }
                  /* repeat until end of pipeline */
                  while(!type && t->tre.tretyp==TFIL);
                  sh.inpipe = pvn;
                  sh.outpipe = 0;
                  if(type == 0)
                        /*
                         * execute last element of pipeline
                         * in the current process
                         */
                        sh_exec(t,flags);
                  else
                        /* execution failure, close pipe */
                        sh_pclose(pvn);
                  pipejob = savepipe;
#ifdef SIGTSTP
                  if(!pipejob && sh_isstate(SH_MONITOR))
                        tcsetpgrp(JOBTTY,sh.pid);
#endif /*SIGTSTP */
                  job.curpgid = savepgid;
                  break;
                }

                case TLST:
                {
                  /*  a list of commands are executed here */
                  do
                  {
                        sh_exec(t->lst.lstlef,errorflg|OPTIMIZE);
                        t = t->lst.lstrit;
                  }
                  while(t->tre.tretyp == TLST);
                  sh_exec(t,flags);
                  break;
                }

                case TAND:
                  if(type&TTEST)
                        skipexitset++;
                  if(sh_exec(t->lst.lstlef,OPTIMIZE)==0)
                        sh_exec(t->lst.lstrit,flags);
                  break;

                case TORF:
                  if(type&TTEST)
                        skipexitset++;
                  if(sh_exec(t->lst.lstlef,OPTIMIZE)!=0)
                        sh_exec(t->lst.lstrit,flags);
                  break;

                case TFOR: /* for and select */
                {
                  register char **args;
                  register int nargs;
                  register Namval_t *np;
                  int flag = errorflg|OPTIMIZE_FLAG;
                  struct dolnod     *argsav=0;
                  struct comnod     *tp;
                  char *cp, *trap, *nullptr = 0;
                  int nameref, refresh=1;
                  static char *av[5] = { "for", 0, "in" };
#if SHOPT_OPTIMIZE
                  int  jmpval = ((struct checkpt*)sh.jmplist)->mode;
                  struct checkpt buff;
                  void *optlist = sh.optlist;
                  sh.optlist = 0;
                  sh_tclear(t->for_.fortre);
                  sh_pushcontext(&buff,jmpval);
                  jmpval = sigsetjmp(buff.buff,0);
                  if(jmpval)
                        goto endfor;
#endif /* SHOPT_OPTIMIZE */
                  error_info.line = t->for_.forline-sh.st.firstline;
                  if(!(tp=t->for_.forlst))
                  {
                        args=sh.st.dolv+1;
                        nargs = sh.st.dolc;
                        argsav=sh_arguse();
                  }
                  else
                  {
                        args=sh_argbuild(&argn,tp,0);
                        nargs = argn;
                  }
                  np = nv_open(t->for_.fornam, sh.var_tree,NV_NOASSIGN|NV_ARRAY|NV_VARNAME|NV_NOREF);
                  nameref = nv_isref(np)!=0;
                  sh.st.loopcnt++;
                  cp = *args;
                  while(cp && sh.st.execbrk==0)
                  {
                        if(t->tre.tretyp&COMSCAN)
                        {
                              char *val;
                              int save_prompt;
                              /* reuse register */
                              if(refresh)
                              {
                                    sh_menu(sfstderr,nargs,args);
                                    refresh = 0;
                              }
                              save_prompt = sh.nextprompt;
                              sh.nextprompt = 3;
                              sh.timeout = 0;
                              sh.exitval=sh_readline(&sh,&nullptr,0,1,1000*sh.st.tmout);
                              sh.nextprompt = save_prompt;
                              if(sh.exitval||sfeof(sfstdin)||sferror(sfstdin))
                              {
                                    sh.exitval = 1;
                                    break;
                              }
                              if(!(val=nv_getval(nv_scoped(REPLYNOD))))
                                    continue;
                              else
                              {
                                    if(*(cp=val) == 0)
                                    {
                                          refresh++;
                                          goto check;
                                    }
                                    while(type = *cp++)
                                          if(type < '0' && type > '9')
                                                break;
                                    if(type!=0)
                                          type = nargs;
                                    else
                                          type = (int)strtol(val, (char**)0, 10)-1;
                                    if(type<0 || type >= nargs)
                                          cp = "";
                                    else
                                          cp = args[type];
                              }
                        }
                        if(nameref)
                              nv_offattr(np,NV_REF);
                        else if(nv_isattr(np, NV_ARRAY))
                              nv_putsub(np,NIL(char*),0L);
                        nv_putval(np,cp,0);
                        if(nameref)
                              nv_setref(np);
                        if(trap=sh.st.trap[SH_DEBUGTRAP])
                        {
                              av[0] = (t->tre.tretyp&COMSCAN)?"select":"for";
                              av[1] = t->for_.fornam;
                              av[3] = cp;
                              sh_debug(trap,(char*)0,(char*)0,av,0);
                        }
                        sh_exec(t->for_.fortre,flag);
                        flag &= ~OPTIMIZE_FLAG;
                        if(t->tre.tretyp&COMSCAN)
                        {
                              if((cp=nv_getval(nv_scoped(REPLYNOD))) && *cp==0)
                                    refresh++;
                        }
                        else
                              cp = *++args;
                  check:
                        if(sh.st.breakcnt<0)
                              sh.st.execbrk = (++sh.st.breakcnt !=0);
                  }
#if SHOPT_OPTIMIZE
            endfor:
                  sh_popcontext(&buff);
                  sh_tclear(t->for_.fortre);
                  sh_optclear(&sh,optlist);
                  if(jmpval)
                        siglongjmp(*sh.jmplist,jmpval);
#endif /*SHOPT_OPTIMIZE */
                  if(sh.st.breakcnt>0)
                        sh.st.execbrk = (--sh.st.breakcnt !=0);
                  sh.st.loopcnt--;
                  sh_argfree(argsav,0);
                  nv_close(np);
                  break;
                }

                case TWH: /* while and until */
                {
                  register int      r=0;
                  int first = OPTIMIZE_FLAG;
                  Shnode_t *tt = t->wh.whtre;
#if SHOPT_FILESCAN
                  Sfio_t *iop=0;
                  int savein,fd;
#endif /*SHOPT_FILESCAN*/
#if SHOPT_OPTIMIZE
                  int  jmpval = ((struct checkpt*)sh.jmplist)->mode;
                  struct checkpt buff;
                  void *optlist = sh.optlist;
                  sh.optlist = 0;
                  sh_tclear(t->wh.whtre);
                  sh_tclear(t->wh.dotre);
                  sh_pushcontext(&buff,jmpval);
                  jmpval = sigsetjmp(buff.buff,0);
                  if(jmpval)
                        goto endwhile;
#endif /* SHOPT_OPTIMIZE */
#if SHOPT_FILESCAN
                  if(type==TWH && tt->tre.tretyp==TCOM && !tt->com.comarg && tt->com.comio)
                  {
                        fd = sh_redirect(tt->com.comio,3);
                        savein = dup(0);
                        if(fd==0)
                              fd = savein;
                        iop = sfnew(NULL,NULL,SF_UNBOUND,fd,SF_READ);
                        close(0);
                        open("/dev/null",O_RDONLY);
                        sh.offsets[0] = -1;
                        sh.offsets[1] = 0;
                        if(tt->com.comset)
                              nv_setlist(tt->com.comset,NV_IDENT|NV_ASSIGN);
                  }
#endif /*SHOPT_FILESCAN */
                  sh.st.loopcnt++;
                  while(sh.st.execbrk==0)
                  {
#if SHOPT_FILESCAN
                        if(iop)
                        {
                              if(!(sh.cur_line=sfgetr(iop,'\n',SF_STRING)))
                                    break;
                        }
                        else
#endif /*SHOPT_FILESCAN */
                        if((sh_exec(tt,first)==0)!=(type==TWH))
                              break;
                        r = sh_exec(t->wh.dotre,first|errorflg);
                        if(sh.st.breakcnt<0)
                              sh.st.execbrk = (++sh.st.breakcnt !=0);
                        /* This is for the arithmetic for */
                        if(sh.st.execbrk==0 && t->wh.whinc)
                              sh_exec((Shnode_t*)t->wh.whinc,first);
                        first = 0;
                        errorflg &= ~OPTIMIZE_FLAG;
#if SHOPT_FILESCAN
                        sh.offsets[0] = -1;
                        sh.offsets[1] = 0;
#endif /*SHOPT_FILESCAN */
                  }
#if SHOPT_OPTIMIZE
            endwhile:
                  sh_popcontext(&buff);
                  sh_tclear(t->wh.whtre);
                  sh_tclear(t->wh.dotre);
                  sh_optclear(&sh,optlist);
                  if(jmpval)
                        siglongjmp(*sh.jmplist,jmpval);
#endif /*SHOPT_OPTIMIZE */
                  if(sh.st.breakcnt>0)
                        sh.st.execbrk = (--sh.st.breakcnt !=0);
                  sh.st.loopcnt--;
                  sh.exitval= r;
#if SHOPT_FILESCAN
                  if(iop)
                  {
                        sfclose(iop);
                        close(0);
                        dup(savein);
                        sh.cur_line = 0;
                  }
#endif /*SHOPT_FILESCAN */
                  break;
                }
                case TARITH: /* (( expression )) */
                {
                  register char *trap;
                  static char *arg[4]=  {"((", 0, "))"};
                  error_info.line = t->ar.arline-sh.st.firstline;
                  if(!(t->ar.arexpr->argflag&ARG_RAW))
                        arg[1] = word_trim(t->ar.arexpr,OPTIMIZE|ARG_ARITH);
                  else
                        arg[1] = t->ar.arexpr->argval;
                  if(trap=sh.st.trap[SH_DEBUGTRAP])
                        sh_debug(trap,(char*)0, (char*)0, arg, ARG_ARITH);
                  if(sh_isoption(SH_XTRACE))
                  {
                        sh_trace(NIL(char**),0);
                        sfprintf(sfstderr,"((%s))\n",arg[1]);
                  }
                  if(t->ar.arcomp)
                        sh.exitval  = !arith_exec((Arith_t*)t->ar.arcomp);
                  else
                        sh.exitval = !sh_arith(arg[1]);
                  break;
                }

                case TIF:
                  if(sh_exec(t->if_.iftre,OPTIMIZE)==0)
                        sh_exec(t->if_.thtre,flags);
                  else if(t->if_.eltre)
                        sh_exec(t->if_.eltre, flags);
                  else
                        sh.exitval=0; /* force zero exit for if-then-fi */
                  break;

                case TSW:
                {
                  Shnode_t *tt = (Shnode_t*)t;
                  char *trap, *r = word_trim(tt->sw.swarg,OPTIMIZE);
                  error_info.line = t->sw.swline-sh.st.firstline;
                  t= (Shnode_t*)(tt->sw.swlst);
                  if(trap=sh.st.trap[SH_DEBUGTRAP])
                  {
                        static char *av[4] = {"case", 0, "in" };
                        av[1] = r;
                        sh_debug(trap, (char*)0, (char*)0, av, 0);
                  }
                  while(t)
                  {
                        register struct argnod  *rex=(struct argnod*)t->reg.regptr;
                        while(rex)
                        {
                              register char *s;
                              if(rex->argflag&ARG_MAC)
                              {
                                    s = word_trim(rex,OPTIMIZE|ARG_EXP);
                                    while(*s=='\\' && s[1]==0)
                                          s+=2;
                              }
                              else
                                    s = rex->argval;
                              type = (rex->argflag&ARG_RAW);
                              if((type && strcmp(r,s)==0) ||
                                    (!type && (strmatch(r,s)
                                    || trim_eq(r,s))))
                              {
                                    do    sh_exec(t->reg.regcom,(t->reg.regflag?0:flags));
                                    while(t->reg.regflag &&
                                          (t=(Shnode_t*)t->reg.regnxt));
                                    t=0;
                                    break;
                              }
                              else
                                    rex=rex->argnxt.ap;
                        }
                        if(t)
                              t=(Shnode_t*)t->reg.regnxt;
                  }
                  break;
                }

                case TTIME:
                {
                  /* time the command */
                  struct tms before,after;
                  const char *format = e_timeformat;
                  clock_t at, tm[3];
#ifdef timeofday
                  struct timeval tb,ta;
#else
                  clock_t bt;
#endif      /* timeofday */
                  if(type!=TTIME)
                  {
                        sh_exec(t->par.partre,OPTIMIZE);
                        sh.exitval = !sh.exitval;
                        break;
                  }
                  if(t->par.partre)
                  {
                        long timer_on;
                        timer_on = sh_isstate(SH_TIMING);
#ifdef timeofday
                        timeofday(&tb);
                        times(&before);
#else
                        bt = times(&before);
#endif      /* timeofday */
                        job.waitall = 1;
                        sh_onstate(SH_TIMING);
                        sh_exec(t->par.partre,OPTIMIZE);
                        if(!timer_on)
                              sh_offstate(SH_TIMING);
                        job.waitall = 0;
                  }
                  else
                  {
#ifndef timeofday
                        bt = 0;
#endif      /* timeofday */
                        before.tms_utime = before.tms_cutime = 0;
                        before.tms_stime = before.tms_cstime = 0;
                  }
#ifdef timeofday
                  times(&after);
                  timeofday(&ta);
                  at = sh.lim.clk_tck*(ta.tv_sec-tb.tv_sec);
                  at +=  ((sh.lim.clk_tck*(((1000000L/2)/sh.lim.clk_tck)+(ta.tv_usec-tb.tv_usec)))/1000000L);
#else
                  at = times(&after) - bt;
#endif      /* timeofday */
                  tm[0] = at;
                  if(t->par.partre)
                  {
                        Namval_t *np = nv_open("TIMEFORMAT",sh.var_tree,NV_NOADD);
                        if(np)
                        {
                              format = nv_getval(np);
                              nv_close(np);
                        }
                        if(!format)
                              format = e_timeformat;
                  }
                  else
                  {
                        format = strchr(format+1,'\n')+1;
#if 0
                        if(sh.optcount)
                              sfprintf(sfstderr,"%d optimizations\n",sh.optcount);
#endif
                  }
                  tm[1] = after.tms_utime - before.tms_utime;
                  tm[1] += after.tms_cutime - before.tms_cutime;
                  tm[2] = after.tms_stime - before.tms_stime;
                  tm[2] += after.tms_cstime - before.tms_cstime;
                  if(format && *format)
                        p_time(sfstderr,sh_translate(format),tm);
                  break;
                }
                case TFUN:
                {
                  register Namval_t *np;
                  register struct slnod *slp;
                  register char *fname = ((struct functnod*)t)->functnam;
                  register char *cp = strrchr(fname,'.');
                  register Namval_t *npv=0;
#if SHOPT_NAMESPACE
                  if(t->tre.tretyp==TNSPACE)
                  {
                        Dt_t *root,*oldroot, *top=0;
                        Namval_t *oldnspace = sh.namespace;
                        int offset = staktell();
                        long optindex = sh.st.optindex;
                        if(cp)
                              errormsg(SH_DICT,ERROR_exit(1),e_ident,fname);
                        stakputc('.');
                        stakputs(fname);
                        stakputc(0);
                        np = nv_open(stakptr(offset),sh.var_base,NV_NOASSIGN|NV_ARRAY|NV_VARNAME);
                        offset = staktell();
                        sh.namespace = np;
                        if(!(root=nv_dict(np)))
                        {
                              root = dtopen(&_Nvdisc,Dtbag);
                              nv_putval(np,(char*)root,NV_TABLE|NV_NOFREE);
                              sh.st.optindex = 1;
                        }
                        if(oldnspace && dtvnext(dtvnext(sh.var_tree)))
                              top = dtview(sh.var_tree,0);
                        else if(dtvnext(sh.var_tree))
                              top = dtview(sh.var_tree,0);
                        oldroot = sh.var_tree;
                        dtview(root,sh.var_base);
                        sh.var_tree = root;
                        if(top)
                              dtview(sh.var_tree,top);
                        sh_exec(t->for_.fortre,flags);
                        if(dtvnext(sh.var_tree))
                              top = dtview(sh.var_tree,0);
                        sh.var_tree = oldroot;
                        if(top)
                              dtview(top,sh.var_tree);
                        sh.namespace = oldnspace;
                        sh.st.optindex = optindex;
                        break;
                  }
#endif /* SHOPT_NAMESPACE */
                  /* look for discipline functions */
                  error_info.line = t->funct.functline-sh.st.firstline;
                  /* Function names cannot be special builtin */
                  if((np=nv_search(fname,sh.bltin_tree,0)) && nv_isattr(np,BLT_SPC))
                        errormsg(SH_DICT,ERROR_exit(1),e_badfun,fname);
                  if(cp)
                  {
                        int offset = staktell();
                        stakwrite(fname,cp-fname);
                        stakputc(0);
                        npv = nv_open(stakptr(offset),sh.var_base,NV_NOASSIGN|NV_ARRAY|NV_VARNAME);
                        offset = staktell();
                        stakputs(nv_name(npv));
                        stakputs(cp);
                        stakputc(0);
                        fname = stakptr(offset);
                  }
#if SHOPT_NAMESPACE
                  else if(sh.namespace)
                  {
                        int offset = staktell();
                        stakputs(nv_name(sh.namespace));
                        stakputc('.');
                        stakputs(fname);
                        stakputc(0);
                        fname = stakptr(offset);
                  }
#endif /* SHOPT_NAMESPACE */
                  np = nv_open(fname,sh_subfuntree(1),NV_NOASSIGN|NV_ARRAY|NV_VARNAME|NV_NOSCOPE);
                  if(npv)
                  {
                        cp = nv_setdisc(npv,cp+1,np,(Namfun_t*)npv);
                        nv_close(npv);
                        if(!cp)
                              errormsg(SH_DICT,ERROR_exit(1),e_baddisc,fname);
                  }
                  if(np->nvalue.rp)
                  {
                        slp = (struct slnod*)np->nvenv;
                        sh_funstaks(slp->slchild,-1);
                        stakdelete(slp->slptr);
                  }
                  else
                        np->nvalue.rp = new_of(struct Ufunction,0);
                  if(t->funct.functstak)
                  {
                        struct functnod *fp;
                        slp = t->funct.functstak;
                        sh_funstaks(slp->slchild,1);
                        staklink(slp->slptr);
                        np->nvenv = (char*)slp;
                        nv_funtree(np) = (int*)(t->funct.functtre);
                        np->nvalue.rp->hoffset = t->funct.functloc;
                        np->nvalue.rp->lineno = t->funct.functline;
                        np->nvalue.rp->nspace = sh.namespace;
                        np->nvalue.rp->fname = 0;
                        fp = (struct functnod*)(slp+1);
                        if(fp->functtyp==(TFUN|FAMP))
                              np->nvalue.rp->fname = fp->functnam;
                        nv_setsize(np,fp->functline);
                        nv_offattr(np,NV_FPOSIX);
                  }
                  else
                        nv_unset(np);
                  if(type&FPOSIX)
                        nv_onattr(np,NV_FUNCTION|NV_FPOSIX);
                  else
                        nv_onattr(np,NV_FUNCTION);
                  if(type&FPIN)
                        nv_onattr(np,NV_FTMP);
                  break;
                }

                /* new test compound command */
                case TTST:
                {
                  register int n;
                  register char *left;
                  int negate = (type&TNEGATE)!=0;
                  if(type&TTEST)
                        skipexitset++;
                  error_info.line = t->tst.tstline-sh.st.firstline;
                  echeck = 1;
                  if((type&TPAREN)==TPAREN)
                  {
                        sh_exec(t->lst.lstlef,OPTIMIZE);
                        n = !sh.exitval;
                  }
                  else
                  {
                        register int traceon=0;
                        register char *right;
                        register char *trap;
                        char *argv[6];
                        n = type>>TSHIFT;
                        left = word_trim(&(t->lst.lstlef->arg),OPTIMIZE);
                        if(type&TBINARY)
                              right = word_trim(&(t->lst.lstrit->arg),((n==TEST_PEQ||n==TEST_PNE)?ARG_EXP:0)|OPTIMIZE);
                        if(trap=sh.st.trap[SH_DEBUGTRAP])
                              argv[0] = (type&TNEGATE)?((char*)e_tstbegin):"[[";
                        if(sh_isoption(SH_XTRACE))
                        {
                              traceon = sh_trace(NIL(char**),0);
                              sfwrite(sfstderr,e_tstbegin,(type&TNEGATE?5:3));
                        }
                        if(type&TUNARY)
                        {
                              if(traceon)
                                    sfprintf(sfstderr,"-%c %s",n,sh_fmtq(left));
                              if(trap)
                              {
                                    char unop[3];
                                    unop[0] = '-';
                                    unop[1] = n;
                                    unop[2] = 0;
                                    argv[1] = unop;
                                    argv[2] = left;
                                    argv[3] = "]]";
                                    argv[4] = 0;
                                    sh_debug(trap,(char*)0,(char*)0,argv, 0);
                              }
                              n = test_unop(n,left);
                        }
                        else if(type&TBINARY)
                        {
                              char *op;
                              int pattern = 0;
                              if(trap || traceon)
                                    op = (char*)(shtab_testops+(n&037)-1)->sh_name;
                              type >>= TSHIFT;
                              if(type==TEST_PEQ || type==TEST_PNE)
                                    pattern=ARG_EXP;
                              if(trap)
                              {
                                    argv[1] = left;
                                    argv[2] = op;
                                    argv[3] = right;
                                    argv[4] = "]]";
                                    argv[5] = 0;
                                    sh_debug(trap,(char*)0,(char*)0,argv, pattern);
                              }
                              n = test_binop(n,left,right);
                              if(traceon)
                              {
                                    sfprintf(sfstderr,"%s %s ",sh_fmtq(left),op);
                                    if(pattern)
                                          out_pattern(sfstderr,right,-1);
                                    else
                                          sfputr(sfstderr,sh_fmtq(right),-1);
                              }
                        }
                        if(traceon)
                              sfwrite(sfstderr,e_tstend,4);
                  }
                  sh.exitval = ((!n)^negate); 
                  break;
                }
            }
            if(sh.trapnote || (sh.exitval && sh_isstate(SH_ERREXIT)) &&
                  t && echeck) 
                  sh_chktrap();
            /* set $_ */
            if(mainloop && com0)
            {
                  /* store last argument here if it fits */
                  static char lastarg[32];
                  if(sh_isstate(SH_FORKED))
                        sh_done(0);
                  if(sh.lastarg!= lastarg && sh.lastarg)
                        free(sh.lastarg);
                  if(strlen(com[argn-1]) < sizeof(lastarg))
                  {
                        nv_onattr(L_ARGNOD,NV_NOFREE);
                        sh.lastarg = strcpy(lastarg,com[argn-1]);
                  }
                  else
                  {
                        nv_offattr(L_ARGNOD,NV_NOFREE);
                        sh.lastarg = strdup(com[argn-1]);
                  }
            }
            if(!skipexitset)
                  exitset();
            if(!(OPTIMIZE))
            {
                  if(sav != stakptr(0))
                        stakset(sav,0);
                  else if(staktell())
                        stakseek(0);
            }
            if(sh.trapnote&SH_SIGSET)
                  sh_exit(SH_EXITSIG|sh.lastsig);
            if(was_interactive)
                  sh_onstate(SH_INTERACTIVE);
            if(was_monitor)
                  sh_onstate(SH_MONITOR);
            if(was_errexit)
                  sh_onstate(SH_ERREXIT);
      }
      return(sh.exitval);
}

/*
 * test for equality with second argument trimmed
 * returns 1 if r == trim(s) otherwise 0
 */

static int trim_eq(register const char *r,register const char *s)
{
      register char c;
      while(c = *s++)
      {
            if(c=='\\')
                  c = *s++;
            if(c && c != *r++)
                  return(0);
      }
      return(*r==0);
}

/*
 * print out the command line if set -x is on
 */

int sh_trace(register char *argv[], register int nl)
{
      register char *cp;
      register int bracket = 0;
      if(sh_isoption(SH_XTRACE))
      {
            /* make this trace atomic */
            sfset(sfstderr,SF_SHARE|SF_PUBLIC,0);
            if(!(cp=nv_getval(nv_scoped(PS4NOD))))
                  cp = "+ ";
            else
            {
                  sh_offoption(SH_XTRACE);
                  cp = sh_mactry(cp);
                  sh_onoption(SH_XTRACE);
            }
            if(*cp)
                  sfputr(sfstderr,cp,-1);
            if(argv)
            {
                  char *argv0 = *argv;
                  nl = (nl?'\n':-1);
                  /* don't quote [ and [[ */
                  if(*(cp=argv[0])=='[' && (!cp[1] || !cp[2]&&cp[1]=='['))  
                  {
                        sfputr(sfstderr,cp,*++argv?' ':nl);
                        bracket = 1;
                  }
                  while(cp = *argv++)
                  {
                        if(bracket==0 || *argv || *cp!=']')
                              cp = sh_fmtq(cp);
                        if(sh.prefix && cp!=argv0 && *cp!='-')
                        {
                              if(*cp=='.' && cp[1]==0)
                                    cp = sh.prefix;
                              else
                                    sfputr(sfstderr,sh.prefix,'.');
                        }
                        sfputr(sfstderr,cp,*argv?' ':nl);
                  }
                  sfset(sfstderr,SF_SHARE|SF_PUBLIC,1);
            }
            return(1);
      }
      return(0);
}


static char *word_trim(register struct argnod *arg, int flags)
{
      register char *sp = arg->argval;
      if((arg->argflag&ARG_RAW))
            return(sp);
      if(flags&ARG_OPTIMIZE)
            arg->argchn.ap=0;
      if(!(sp=arg->argchn.cp))
      {
            sh_macexpand(arg,NIL(struct argnod**),flags);
            sp = arg->argchn.cp;
            if(!OPTIMIZE || !(arg->argflag&ARG_MAKE))
                  arg->argchn.cp = 0;
            arg->argflag &= ~ARG_MAKE;
      }
      else
            sh.optcount++;
      return(sp);
}


/*
 * This routine creates a subshell by calling fork() or vfork()
 * If ((flags&COMASK)==TCOM), then vfork() is permitted
 * If fork fails, the shell sleeps for exponentially longer periods
 *   and tries again until a limit is reached.
 * SH_FORKLIM is the max period between forks - power of 2 usually.
 * Currently shell tries after 2,4,8,16, and 32 seconds and then quits
 * Failures cause the routine to error exit.
 * Parent links to here-documents are removed by the child
 * Traps are reset by the child
 * The process-id of the child is returned to the parent, 0 to the child.
 */

static void timed_out(void *handle)
{
      NOT_USED(handle);
      timeout = 0;
}


/*
 * called by parent and child after fork by sh_fork()
 */
pid_t _sh_fork(register pid_t parent,int flags,int *jobid)
{
      static long forkcnt = 1000L;
      pid_t curpgid = job.curpgid;
      pid_t postid = (flags&FAMP)?0:curpgid;
      if(parent<0)
      {
            if((forkcnt *= 2) > 1000L*SH_FORKLIM)
            {
                  forkcnt=1000L;
                  errormsg(SH_DICT,ERROR_system(ERROR_NOEXEC),e_nofork);
            }
            sh_sigcheck();
            timeout = (void*)sh_timeradd(forkcnt, 0, timed_out, NIL(void*));
            job_wait((pid_t)1);
            if(timeout)
            {
                  timerdel(timeout);
                  forkcnt /= 2;
            }
            return(-1);
      }
      forkcnt=1000L;
      if(parent)
      {
            int myjob;
            sh.nforks++;
            if(job.toclear)
                  job_clear();
#ifdef JOBS
            /* first process defines process group */
            if(sh_isstate(SH_MONITOR))
            {
                  /*
                   * errno==EPERM means that an earlier processes
                   * completed.  Make parent the job group id.
                   */
                  if(postid==0)
                        job.curpgid = parent;
                  if(job.jobcontrol || (flags&FAMP))
                  {
                        if(setpgid(parent,job.curpgid)<0 && errno==EPERM)
                              setpgid(parent,parent);
                  }
            }
#endif /* JOBS */
            if(flags&FCOOP)
                  sh.cpid = parent;
            myjob = job_post(parent,postid);
            if(flags&FAMP)
                  job.curpgid = curpgid;
            if(jobid)
                  *jobid = myjob;
            return(parent);
      }
#if !_std_malloc
      vmtrace(-1);
#endif
      /* This is the child process */
      if(sh.trapnote&SH_SIGTERM)
            sh_exit(SH_EXITSIG|SIGTERM);
      sh.nforks=0;
      timerdel(NIL(void*));
#ifdef JOBS
      if(!job.jobcontrol && !(flags&FAMP))
            sh_offstate(SH_MONITOR);
      if(sh_isstate(SH_MONITOR))
      {
            parent = getpid();
            if(postid==0)
                  job.curpgid = parent;
            while(setpgid(0,job.curpgid)<0 && job.curpgid!=parent)
                  job.curpgid = parent;
#   ifdef SIGTSTP
            if(job.curpgid==parent &&  !(flags&FAMP))
                  tcsetpgrp(job.fd,job.curpgid);
#   endif /* SIGTSTP */
      }
#   ifdef SIGTSTP
      if(job.jobcontrol)
      {
            signal(SIGTTIN,SIG_DFL);
            signal(SIGTTOU,SIG_DFL);
            signal(SIGTSTP,SIG_DFL);
      }
#   endif /* SIGTSTP */
      job.jobcontrol = 0;
#endif /* JOBS */
      job.toclear = 1;
      sh.login_sh = 0;
      sh_offoption(SH_LOGIN_SHELL);
      sh_onstate(SH_FORKED);
      sh_onstate(SH_NOLOG);
      sh.fn_depth = 0;
#if SHOPT_ACCT
      sh_accsusp();
#endif      /* SHOPT_ACCT */
      /* Reset remaining signals to parent */
      /* except for those `lost' by trap   */
      sh_sigreset(2);
      sh.subshell = 0;
      return(0);
}

pid_t sh_fork(int flags, int *jobid)
{
      register pid_t parent;
#if SHOPT_FASTPIPE
      if(sffileno(sfstdin)<0)
      {
            off_t current = sfseek(sfstdin,(off_t)0,SEEK_CUR);
            sfseek(sfstdin,(off_t)0,SEEK_END);
            sfdisc(sfstdin,SF_POPDISC);
            fcntl(sffileno(sfstdin),F_SETFD,0);
            sh_iostream(0);
            sfseek(sfstdin,current,SEEK_SET);
      }
#endif /* SHOPT_FASTPIPE */
      sfsync(NIL(Sfio_t*));
      sh.trapnote &= ~SH_SIGTERM;
      job_fork(-1);
      while(_sh_fork(parent=fork(),flags,jobid) < 0);
      job_fork(parent);
      return(parent);
}

/*
 * This routine is used to execute the given function <fun> in a new scope
 * If <fun> is NULL, then arg points to a structure containing a pointer
 *  to a function that will be executed in the current environment.
 */
int sh_funscope(int argn, char *argv[],int(*fun)(void*),void *arg,int execflg)
{
      register char     *trap;
      register int      nsig;
      struct dolnod     *argsav=0,*saveargfor;
      struct sh_scoped savst, *prevscope = sh.st.self;
      struct argnod     *envlist=0;
      Shopt_t           savopt;
      int         jmpval;
      int         r = 0;
      char        *savstak;
      struct funenv     *fp;
      struct checkpt    buff;
      Namval_t    *nspace = sh.namespace;
      savopt = sh.options;
      sh.st.lineno = error_info.line;
      *prevscope = sh.st;
      sh_offoption(SH_ERREXIT);
      sh.st.prevst = prevscope;
      sh.st.self = &savst;
      sh.topscope = (Shscope_t*)sh.st.self;
      sh.st.opterror = sh.st.optchar = 0;
      sh.st.optindex = 1;
      sh.st.loopcnt = 0;
      if(!fun)
      {
            fp = (struct funenv*)arg;
            envlist = fp->env;
#if 0
            sh.st.firstline = (fp->node)->nvalue.rp->lineno;
#endif
      }
      prevscope->save_tree = sh.var_tree;
      nv_scope(envlist);
      if(dtvnext(prevscope->save_tree)!= (sh.namespace?sh.var_base:0))
      {
            /* eliminate parent scope */
            Dt_t *dt = dtview(sh.var_tree,0);
            dtview(sh.var_tree,dtvnext(prevscope->save_tree));
      }
      sh.st.save_tree = sh.var_tree;
      if(!fun)
      {
            Namval_t *np;
            if(nv_isattr(fp->node,NV_TAGGED))
                  sh_onoption(SH_XTRACE);
            else
                  sh_offoption(SH_XTRACE);
#if SHOPT_NAMESPACE
            if((np=(fp->node)->nvalue.rp->nspace) && np!=sh.namespace)
            {
                  Dt_t *dt = sh.var_tree;
                  dtview(dt,0);
                  dtview(dt,nv_dict(np));
                  sh.var_tree = nv_dict(np);
                  sh.namespace = np;
            }
#endif /* SHOPT_NAMESPACE */
      }
      sh.st.cmdname = argv[0];
      /* save trap table */
      if((nsig=sh.st.trapmax*sizeof(char*))>0 || sh.st.trapcom[0])
      {
            nsig += sizeof(char*);
            memcpy(savstak=stakalloc(nsig),(char*)&sh.st.trapcom[0],nsig);
      }
      sh_sigreset(0);
      argsav = sh_argnew(argv,&saveargfor);
      sh_pushcontext(&buff,SH_JMPFUN);
      errorpush(&buff.err,0);
      error_info.id = argv[0];
      sh.st.var_local = sh.var_tree;
      jmpval = sigsetjmp(buff.buff,0);
      if(!fun)
      {
            sh.st.filename = fp->node->nvalue.rp->fname;
            nv_putval(SH_PATHNAMENOD, sh.st.filename ,NV_NOFREE);
            nv_putval(SH_FUNNAMENOD,nv_name(fp->node),NV_NOFREE);
      }
      if(jmpval == 0)
      {
            if(sh.fn_depth++ > MAXDEPTH)
                  siglongjmp(*sh.jmplist,SH_JMPERRFN);
            else if(fun)
                  r= (*fun)(arg);
            else
            {
                  sh_exec((Shnode_t*)(nv_funtree((fp->node))),execflg|SH_ERREXIT);
                  r = sh.exitval;
            }
      }
      if(--sh.fn_depth==1 && jmpval==SH_JMPERRFN)
            errormsg(SH_DICT,ERROR_exit(1),e_toodeep,argv[0]);
      sh_popcontext(&buff);
      if (sh.st.self != &savst)
            sh.var_tree = (Dt_t*)savst.save_tree;
      nv_unscope();
      sh.namespace = nspace;
      sh.var_tree = (Dt_t*)prevscope->save_tree;
      sh_argreset(argsav,saveargfor);
      trap = sh.st.trapcom[0];
      sh.st.trapcom[0] = 0;
      sh_sigreset(1);
      if (sh.st.self != &savst)
            *sh.st.self = sh.st;
      sh.st = *prevscope;
      sh.topscope = (Shscope_t*)prevscope;
      nv_getval(nv_scoped(IFSNOD));
      if(nsig)
            memcpy((char*)&sh.st.trapcom[0],savstak,nsig);
      sh.trapnote=0;
      if(nsig)
            stakset(savstak,0);
      sh.options = savopt;
      if(trap)
      {
            sh_trap(trap,0);
            free(trap);
      }
      if(sh.exitval > SH_EXITSIG)
            sh_fault(sh.exitval&SH_EXITMASK);
      if(jmpval > SH_JMPFUN)
      {
            sh_chktrap();
            siglongjmp(*sh.jmplist,jmpval);
      }
      return(r);
}


static void sh_funct(Namval_t *np,int argn, char *argv[],struct argnod *envlist,int execflg)
{
      struct funenv fun;
      char *fname = nv_getval(SH_FUNNAMENOD);
      if(nv_isattr(np,NV_FPOSIX))
      {
            char *save;
            int loopcnt = sh.st.loopcnt;
            sh.posix_fun = np;
            opt_info.index = opt_info.offset = 0;
            error_info.errors = 0;
            save = argv[-1];
            argv[-1] = 0;
            nv_putval(SH_FUNNAMENOD, nv_name(np),NV_NOFREE);
            sh.st.loopcnt = 0;
            b_dot_cmd(argn+1,argv-1,&sh);
            sh.st.loopcnt = loopcnt;
            argv[-1] = save;
      }
      else
      {
            fun.env = envlist;
            fun.node = np;
            sh_funscope(argn,argv,0,&fun,execflg);
      }
      nv_putval(SH_FUNNAMENOD,fname,NV_NOFREE);
      nv_putval(SH_PATHNAMENOD, sh.st.filename ,0);
}

/*
 * external interface to execute a function without arguments
 * <np> is the function node
 * If <nq> is not-null, then sh.name and sh.subscript will be set
 */
int sh_fun(Namval_t *np, Namval_t *nq, char *argv[])
{
      register int offset;
      register char *base;
      int n=0;
      char *av[2];
      Fcin_t save;
      fcsave(&save);
      if((offset=staktell())>0)
            base=stakfreeze(0);
      if(!argv)
      {
            argv = av;
            argv[1]=0;
      }
      argv[0] = nv_name(np);
      while(argv[n])
            n++;
      if(nq)
      {
            nv_putval(SH_NAMENOD, nv_name(nq), NV_NOFREE);
            if(nv_arrayptr(nq))
                  nv_putval(SH_SUBSCRNOD,nv_getsub(nq),NV_NOFREE);
      }
      if(is_abuiltin(np))
      {
            int jmpval;
            struct checkpt buff;
            sh_pushcontext(&buff,SH_JMPCMD);
            jmpval = sigsetjmp(buff.buff,1);
            if(jmpval == 0)
            {
                  void *context = nv_context(np);
                  errorpush(&buff.err,0);
                  error_info.id = argv[0];
                  opt_info.index = opt_info.offset = 0;
                  opt_info.disc = 0;
                  sh.exitval = 0;
                  if(!context)
                        context = (void*)&sh;
                  sh.exitval = (*funptr(np))(n,argv,context);
            }
            sh_popcontext(&buff);
            if(jmpval>SH_JMPCMD)
                  siglongjmp(*sh.jmplist,jmpval);
      }
      else
            sh_funct(np,n,argv,(struct argnod*)0,sh_isstate(SH_ERREXIT));
      if(nq)
      {
            nv_unset(SH_NAMENOD);
            nv_unset(SH_SUBSCRNOD);
      }
      fcrestore(&save);
      if(offset>0)
            stakset(base,offset);
      return(sh.exitval);
}

/*
 * This dummy routine is called by built-ins that do recursion
 * on the file system (chmod, chgrp, chown).  It causes
 * the shell to invoke the non-builtin version in this case
 */
int cmdrecurse(int argc, char* argv[], int ac, char* av[])
{
      NOT_USED(argc);
      NOT_USED(argv[0]);
      NOT_USED(ac);
      NOT_USED(av[0]);
      return(SH_RUNPROG);
}

/*
 * set up pipe for cooperating process 
 */
static void coproc_init(int pipes[])
{
      if(sh.coutpipe>=0 && sh.cpid)
            errormsg(SH_DICT,ERROR_exit(1),e_pexists);
      sh.cpid = 0;
      if(sh.cpipe[0]<=0 || sh.cpipe[1]<=0)
      {
            /* first co-process */
            sh_pclose(sh.cpipe);
            sh_pipe(sh.cpipe);
            if(fcntl(*sh.cpipe,F_SETFD,FD_CLOEXEC)>=0)
                  sh.fdstatus[sh.cpipe[0]] |= IOCLEX;
            sh.fdptrs[sh.cpipe[0]] = sh.cpipe;
                  
            if(fcntl(sh.cpipe[1],F_SETFD,FD_CLOEXEC) >=0)
                  sh.fdstatus[sh.cpipe[1]] |= IOCLEX;
      }
      sh.outpipe = sh.cpipe;
      sh_pipe(sh.inpipe=pipes);
      sh.coutpipe = sh.inpipe[1];
      sh.fdptrs[sh.coutpipe] = &sh.coutpipe;
      if(fcntl(sh.outpipe[0],F_SETFD,FD_CLOEXEC)>=0)
            sh.fdstatus[sh.outpipe[0]] |= IOCLEX;
}

#if SHOPT_SPAWN


#if defined(SHOPT_AMP) || !defined(_lib_fork)
/*
 * print out function definition
 */
static void print_fun(register Namval_t* np, void *data)
{
      register char *format;
      NOT_USED(data);
      if(!is_afunction(np) || !np->nvalue.ip)
            return;
      if(nv_isattr(np,NV_FPOSIX))
            format="%s()\n{ ";
      else
            format="function %s\n{ ";
      sfprintf(sfstdout,format,nv_name(np));
      sh_deparse(sfstdout,(Shnode_t*)(nv_funtree(np)),0);
      sfwrite(sfstdout,"}\n",2);
}

/*
 * create a shell script consisting of t->fork.forktre and execute it
 */
static int run_subshell(const Shnode_t *t,pid_t grp)
{
      static char prolog[] = "(print $(typeset +A);set; typeset -p; print .sh.dollar=$$;set +o)";
      register int i, fd, trace = sh_isoption(SH_XTRACE);
      int pin,pout;
      pid_t pid;
      char *arglist[2], *envlist[2], devfd[12], *cp;
      Sfio_t *sp = sftmp(0);
      envlist[0] = "_=ksh";
      envlist[1] = 0;
      arglist[0] = error_info.id?error_info.id:sh.shname;
      if(*arglist[0]=='-')
            arglist[0]++;
      arglist[1] = devfd;
      strncpy(devfd,e_devfdNN,sizeof(devfd));
      arglist[2] = 0;
      sfstack(sfstdout,sp);
      if(trace)
            sh_offoption(SH_XTRACE);
      sfwrite(sfstdout,"typeset -A -- ",14);
      sh_trap(prolog,0);
      nv_scan(sh.fun_tree, print_fun, (void*)0,0, 0);
      if(sh.st.dolc>0)
      {
            /* pass the positional parameters */
            char **argv = sh.st.dolv+1;
            sfwrite(sfstdout,"set --",6);
            while(*argv)
                  sfprintf(sfstdout," %s",sh_fmtq(*argv++));
            sfputc(sfstdout,'\n');
      }
      pin = (sh.inpipe?sh.inpipe[1]:0);
      pout = (sh.outpipe?sh.outpipe[0]:0);
      for(i=3; i < 10; i++)
      {
            if(sh.fdstatus[i]&IOCLEX && i!=pin && i!=pout)
            {
                  sfprintf(sfstdout,"exec %d<&%d\n",i,i);
                  fcntl(i,F_SETFD,0);
            }
      }
      sfprintf(sfstdout,"LINENO=%d\n",t->fork.forkline);
      if(trace)
      {
            sfwrite(sfstdout,"set -x\n",7);
            sh_onoption(SH_XTRACE);
      }
      sfstack(sfstdout,NIL(Sfio_t*));
      sh_deparse(sp,t->fork.forktre,0);
      sfseek(sp,(Sfoff_t)0,SEEK_SET);
      fd = sh_dup(sffileno(sp));
      cp = devfd+8;
      if(fd>9)
            *cp++ = '0' + (fd/10);
      *cp++ = '0' + fd%10;
      *cp = 0;
      sfclose(sp);
      sfsync(NIL(Sfio_t*));
      if(!sh.shpath)
            sh.shpath = pathshell();
      pid = spawnveg(sh.shpath,arglist,envlist,grp);
      close(fd);
      for(i=3; i < 10; i++)
      {
            if(sh.fdstatus[i]&IOCLEX && i!=pin && i!=pout)
                  fcntl(i,F_SETFD,FD_CLOEXEC);
      }
      if(pid <=0)
            errormsg(SH_DICT,ERROR_system(ERROR_NOEXEC),e_exec,arglist[0]);
      return(pid);
}
#endif /* !_lib_fork */

static void sigreset(int mode)
{
      register char   *trap;
      register int sig=sh.st.trapmax;
      while(sig-- > 0)
      {
            if((trap=sh.st.trapcom[sig]) && *trap==0)
                  signal(sig,mode?sh_fault:SIG_IGN);
      }
}

/*
 * A combined fork/exec for systems with slow or non-existent fork()
 */
static pid_t sh_ntfork(const Shnode_t *t,char *argv[],int *jobid,int flag)
{
      static pid_t      spawnpid;
      static int  savetype;
      static int  savejobid;
      Shell_t *shp = sh_getinterp();
      struct checkpt buff;
      int otype=0, scope=0, jmpval;
      int jobwasset=0, sigwasset=0;
      char **arge, *path;
      pid_t grp = 0;
      Pathcomp_t *pp;
      if(flag)
      {
            otype = savetype;
            savetype=0;
      }
#   if defined(SHOPT_AMP) || !defined(_lib_fork)
      if(!argv)
      {
            register Shnode_t *tchild = t->fork.forktre;
            int optimize=0;
            otype = t->tre.tretyp;
            savetype = otype;
            spawnpid = 0;
#     ifndef _lib_fork
            if((tchild->tre.tretyp&COMMSK)==TCOM)
            {
                  Namval_t *np = (Namval_t*)(tchild->com.comnamp);
                  if(np)
                  {
                        path = nv_name(np);
                        if(!nv_isattr(np,BLT_ENV))
                              np=0;
                        else if(strcmp(path,"echo")==0 || memcmp(path,"print",5)==0)
                              np=0;
                  }
                  else if(!tchild->com.comarg)
                        optimize=1;
                  else if(tchild->com.comtyp&COMSCAN)
                  {
                        if(tchild->com.comarg->argflag&ARG_RAW)
                              path = tchild->com.comarg->argval;
                        else
                              path = 0;
                  }
                  else
                        path = ((struct dolnod*)tchild->com.comarg)->dolval[ARG_SPARE];
                  if(!np && path && !nv_search(path,shp->fun_tree,0))
                        optimize=1;
            }
#     endif
            sh_pushcontext(&buff,SH_JMPIO);
            jmpval = sigsetjmp(buff.buff,0);
            {
                  if((otype&FINT) && !sh_isstate(SH_MONITOR))
                  {
                        signal(SIGQUIT,SIG_IGN);
                        signal(SIGINT,SIG_IGN);
                        if(!shp->st.ioset)
                        {
                              sh_iosave(0,buff.topfd);
                              sh_iorenumber(sh_chkopen(e_devnull),0);
                        }
                  }
                  if(otype&FPIN)
                  {
                        int fd = shp->inpipe[1];
                        sh_iosave(0,buff.topfd);
                        sh_iorenumber(shp->inpipe[0],0);
                        if(fd>=0 && (!(otype&FPOU) || (otype&FCOOP)) && fcntl(fd,F_SETFD,FD_CLOEXEC)>=0)
                              shp->fdstatus[fd] |= IOCLEX;
                  }
                  if(otype&FPOU)
                  {
                        sh_iosave(1,buff.topfd);
                        sh_iorenumber(sh_dup(shp->outpipe[1]),1);
                        if(fcntl(shp->outpipe[0],F_SETFD,FD_CLOEXEC)>=0)
                              shp->fdstatus[shp->outpipe[0]] |= IOCLEX;
                  }
      
                  if(t->fork.forkio)
                        sh_redirect(t->fork.forkio,0);
                  if(optimize==0)
                  {
#ifdef SIGTSTP
                        if(job.jobcontrol)
                        {
                              signal(SIGTTIN,SIG_DFL);
                              signal(SIGTTOU,SIG_DFL);
                        }
#endif /* SIGTSTP */
#ifdef JOBS
                        if(sh_isstate(SH_MONITOR) && (job.jobcontrol || (otype&FAMP)))
                        {
                              if((otype&FAMP) || job.curpgid==0)
                                    grp = 1;
                              else
                                    grp = job.curpgid;
                        }
#endif /* JOBS */
                        spawnpid = run_subshell(t,grp);
                  }
                  else
                  {
                        sh_exec(tchild,SH_NTFORK);
                        if(jobid)
                              *jobid = savejobid;
                  }
            }
            sh_popcontext(&buff);
            if((otype&FINT) && !sh_isstate(SH_MONITOR))
            {
                  signal(SIGQUIT,sh_fault);
                  signal(SIGINT,sh_fault);
            }
            if((otype&FPIN) && (!(otype&FPOU) || (otype&FCOOP)) && fcntl(shp->inpipe[1],F_SETFD,FD_CLOEXEC)>=0)
                  shp->fdstatus[shp->inpipe[1]] &= ~IOCLEX;
            if(t->fork.forkio || otype)
                  sh_iorestore(buff.topfd,jmpval);
            if(optimize==0)
            {
#ifdef SIGTSTP
                  if(job.jobcontrol)
                  {
                        signal(SIGTTIN,SIG_IGN);
                        signal(SIGTTOU,SIG_IGN);
                  }
#endif /* SIGTSTP */
                  if(spawnpid>0)
                        _sh_fork(spawnpid,otype,jobid);
                  if(grp>0 && !(otype&FAMP))
                  {
                        while(tcsetpgrp(job.fd,job.curpgid)<0 && job.curpgid!=spawnpid)
                              job.curpgid = spawnpid;
                  }
            }
            savetype=0;
            if(jmpval>SH_JMPIO)
                  siglongjmp(*shp->jmplist,jmpval);
            if(spawnpid<0 && (otype&FCOOP))
            {
                  sh_close(shp->coutpipe);
                  sh_close(shp->cpipe[1]);
                  shp->cpipe[1] = -1;
                  shp->coutpipe = -1;
            }
            shp->exitval = 0;
            return(spawnpid);
      }
#   endif /* !_lib_fork */
      sh_pushcontext(&buff,SH_JMPCMD);
      errorpush(&buff.err,ERROR_SILENT);
      jmpval = sigsetjmp(buff.buff,0);
      if(jmpval == 0)
      {
            if((otype&FINT) && !sh_isstate(SH_MONITOR))
            {
                  signal(SIGQUIT,SIG_IGN);
                  signal(SIGINT,SIG_IGN);
            }
            spawnpid = -1;
            if(t->com.comio)
                  sh_redirect(t->com.comio,0);
            error_info.id = *argv;
            if(t->com.comset)
            {
                  scope++;
                  nv_scope(t->com.comset);
            }
            if(!strchr(path=argv[0],'/')) 
            {
#ifdef PATH_BFPATH
                  Namval_t *np;
                  if((np=nv_search(path,shp->track_tree,0)) && !nv_isattr(np,NV_NOALIAS) && np->nvalue.cp)
                        path = nv_getval(np);
                  else if(path_absolute(path,NIL(Pathcomp_t*)))
                  {
                        path = stakptr(PATH_OFFSET);
                        stakfreeze(0);
                  }
                  else
                  {
                        pp=path_get(path);
                        while(pp)
                        {
                              if(pp->len==1 && *pp->name=='.')
                                    break;
                              pp = pp->next;
                        }
                        if(!pp)
                              path = 0;
                  }
#else
                  path = shp->lastpath;
#endif
            }
            if(!path)
            {
                  spawnpid = -1;
                  goto fail;
            }
            arge = sh_envgen();
            shp->exitval = 0;
#ifdef SIGTSTP
            if(job.jobcontrol)
            {
                  signal(SIGTTIN,SIG_DFL);
                  signal(SIGTTOU,SIG_DFL);
                  jobwasset++;
            }
#endif /* SIGTSTP */
#ifdef JOBS
            if(sh_isstate(SH_MONITOR) && (job.jobcontrol || (otype&FAMP)))
            {
                  if((otype&FAMP) || job.curpgid==0)
                        grp = 1;
                  else
                        grp = job.curpgid;
            }
#endif /* JOBS */

            sfsync(NIL(Sfio_t*));
            sigreset(0);      /* set signals to ignore */
            sigwasset++;
              /* find first path that has a library component */
            for(pp=path_get(argv[0]); pp && !pp->lib ; pp=pp->next);
            spawnpid = path_spawn(path,argv,arge,pp,(grp<<1)|1);
            if(spawnpid < 0 && errno==ENOEXEC)
            {
                  char devfd[14];
                  int fd = open(path,O_RDONLY);
                  argv[-1] = argv[0];
                  argv[0] = path;
                  if(fd>=0)
                  {
                        sfsprintf(devfd,sizeof(devfd),"/dev/fd/%d\0",fd);
                        argv[0] =  devfd;
                  }
                  if(!shp->shpath)
                        shp->shpath = pathshell();
                  spawnpid = path_spawn(shp->shpath,&argv[-1],arge,pp,(grp<<1)|1);
                  if(fd>=0)
                        close(fd);
                  argv[0] = argv[-1];
            }
      fail:
            if(spawnpid < 0) switch(errno=shp->path_err)
            {
                case ENOENT:
                  errormsg(SH_DICT,ERROR_system(ERROR_NOENT),e_found+4);
                default:
                  errormsg(SH_DICT,ERROR_system(ERROR_NOEXEC),e_exec+4);
            }
      }
      sh_popcontext(&buff);
#ifdef SIGTSTP
      if(jobwasset)
      {
            signal(SIGTTIN,SIG_IGN);
            signal(SIGTTOU,SIG_IGN);
      }
#endif /* SIGTSTP */
      if(sigwasset)
            sigreset(1);      /* restore ignored signals */
      if(scope)
      {
            nv_unscope();
            if(jmpval==SH_JMPSCRIPT)
                  nv_setlist(t->com.comset,NV_EXPORT|NV_IDENT|NV_ASSIGN);
      }
      if(t->com.comio)
            sh_iorestore(buff.topfd,jmpval);
      if(jmpval>SH_JMPCMD)
            siglongjmp(*shp->jmplist,jmpval);
      if(spawnpid>0)
      {
            _sh_fork(spawnpid,otype,jobid);
#ifdef JOBS
            if(grp==1)
                  job.curpgid = spawnpid;
#   ifdef SIGTSTP
            if(grp>0 && !(otype&FAMP))
            {
                  while(tcsetpgrp(job.fd,job.curpgid)<0 && job.curpgid!=spawnpid)
                        job.curpgid = spawnpid;
            }
#   endif /* SIGTSTP */
#endif /* JOBS */
            savejobid = *jobid;
            if(otype)
                  return(0);
      }
      return(spawnpid);
}

#   ifdef _was_lib_fork
#     define _lib_fork  1
#   endif
#   ifndef _lib_fork
      pid_t fork(void)
      {
            errormsg(SH_DICT,ERROR_exit(3),e_notimp,"fork");
            return(-1);
      }
#   endif /* _lib_fork */
#endif /* SHOPT_SPAWN */

/*
 * override procrun() since it is used in libcmd
 */
#include    <proc.h>
int procrun(const char *path, char *argv[])
{
      if(sh.subshell)
            sh_subtmpfile();
      return(procclose(procopen(path, argv, NiL, NiL, PROC_FOREGROUND|PROC_GID
|PROC_UID)));
}

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