xref: /illumos-gate/usr/src/contrib/ast/src/cmd/ksh93/sh/name.c (revision b30d1939)

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1982-2012 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                 Eclipse Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*          http://www.eclipse.org/org/documents/epl-v10.html           *
*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                  David Korn <dgk@research.att.com>                   *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * AT&T Labs
 *
 */
/*
 * Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved.
 */

#define putenv	___putenv

#include	"defs.h"
#include	"variables.h"
#include	"path.h"
#include	"lexstates.h"
#include	"timeout.h"
#include	"FEATURE/externs"
#include	"streval.h"

#define NVCACHE		8	/* must be a power of 2 */
#define Empty	((char*)(e_sptbnl+3))
static char	*savesub = 0;
static char	Null[1];
static Namval_t	NullNode;
static Dt_t	*Refdict;
static Dtdisc_t	_Refdisc =
{
	offsetof(struct Namref,np),sizeof(struct Namval_t*),sizeof(struct Namref)
};

#if !_lib_pathnative && _lib_uwin_path

#define _lib_pathnative		1

extern int	uwin_path(const char*, char*, int);

size_t
pathnative(const char* path, char* buf, size_t siz)
{
	return uwin_path(path, buf, siz);
}

#endif /* _lib_pathnative */

static void	attstore(Namval_t*,void*);
#ifndef _ENV_H
    static void	pushnam(Namval_t*,void*);
    static char	*staknam(Namval_t*, char*);
#endif
static void	rightjust(char*, int, int);
static char	*lastdot(char*, int);

struct adata
{
	Shell_t		*sh;
	Namval_t	*tp;
	char		*mapname;
	char		**argnam;
	int		attsize;
	char		*attval;
};

#if SHOPT_TYPEDEF
    struct sh_type
    {
	void		*previous;
	Namval_t	**nodes;
	Namval_t	*rp;
	short		numnodes;
	short		maxnodes;
    };
#endif /*SHOPT_TYPEDEF */

#if NVCACHE
    struct Namcache
    {
	struct Cache_entry
	{
		Dt_t		*root;
		Dt_t		*last_root;
		char		*name;
		Namval_t	*np;
		Namval_t	*last_table;
		Namval_t	*namespace;
		int		flags;
		short		size;
		short		len;
	} entries[NVCACHE];
	short		index;
	short		ok;
    };
    static struct Namcache nvcache;
#endif

char		nv_local = 0;
#ifndef _ENV_H
static void(*nullscan)(Namval_t*,void*);
#endif

#if ( SFIO_VERSION  <= 20010201L )
#   define _data        data
#endif

#if !SHOPT_MULTIBYTE
#   define mbchar(p)       (*(unsigned char*)p++)
#endif /* SHOPT_MULTIBYTE */

/* ========	name value pair routines	======== */

#include	"shnodes.h"
#include	"builtins.h"

static char *getbuf(size_t len)
{
	static char *buf;
	static size_t buflen;
	if(buflen < len)
	{
		if(buflen==0)
			buf = (char*)malloc(len);
		else
			buf = (char*)realloc(buf,len);
		buflen = len;
	}
	return(buf);
}

#ifdef _ENV_H
void sh_envput(Env_t* ep,Namval_t *np)
{
	int offset = staktell();
	Namarr_t *ap = nv_arrayptr(np);
	char *val;
	if(ap)
	{
		if(ap->nelem&ARRAY_UNDEF)
			nv_putsub(np,"0",0L);
		else if(!(val=nv_getsub(np)) || strcmp(val,"0"))
			return;
	}
	if(!(val = nv_getval(np)))
		return;
	stakputs(nv_name(np));
	stakputc('=');
	stakputs(val);
	stakseek(offset);
	env_add(ep,stakptr(offset),ENV_STRDUP);
}
#endif

/*
 * output variable name in format for re-input
 */
void nv_outname(Sfio_t *out, char *name, int len)
{
	const char *cp=name, *sp;
	int c, offset = staktell();
	while(sp= strchr(cp,'['))
	{
		if(len>0 && cp+len <= sp)
			break;
		sfwrite(out,cp,++sp-cp);
		stakseek(offset);
		while(c= *sp++)
		{
			if(c==']')
				break;
			else if(c=='\\')
			{
				if(*sp=='[' || *sp==']' || *sp=='\\')
					c = *sp++;
			}
			stakputc(c);
		}
		stakputc(0);
		sfputr(out,sh_fmtq(stakptr(offset)),-1);
		if(len>0)
		{
			sfputc(out,']');
			return;
		}
		cp = sp-1;
	}
	if(*cp)
	{
		if(len>0)
			sfwrite(out,cp,len);
		else
			sfputr(out,cp,-1);
	}
	stakseek(offset);
}

#if SHOPT_TYPEDEF
Namval_t *nv_addnode(Namval_t* np, int remove)
{
	Shell_t			*shp = sh_getinterp();
	register struct sh_type	*sp = (struct sh_type*)shp->mktype;
	register int		i;
	register char		*name=0;
	if(sp->numnodes==0 && !nv_isnull(np) && shp->last_table)
	{
		/* could be an redefine */
		Dt_t *root = nv_dict(shp->last_table);
		sp->rp = np;
		nv_delete(np,root,NV_NOFREE);
		np = nv_search(sp->rp->nvname,root,NV_ADD);
	}
	if(sp->numnodes && memcmp(np->nvname,NV_CLASS,sizeof(NV_CLASS)-1))
	{
		name = (sp->nodes[0])->nvname;
		i = strlen(name);
		if(memcmp(np->nvname,name,i))
			return(np);
	}
	if(sp->rp && sp->numnodes)
	{
		/* check for a redefine */
		if(name && np->nvname[i]=='.' && np->nvname[i+1]=='_' && np->nvname[i+2]==0)
			sp->rp = 0;
		else
		{
			Dt_t *root = nv_dict(shp->last_table);
			nv_delete(sp->nodes[0],root,NV_NOFREE);
			dtinsert(root,sp->rp);
			errormsg(SH_DICT,ERROR_exit(1),e_redef,sp->nodes[0]->nvname);
		}
	}
	for(i=0; i < sp->numnodes; i++)
	{
		if(np == sp->nodes[i])
		{
			if(remove)
			{
				while(++i < sp->numnodes)
					sp->nodes[i-1] = sp->nodes[i];
				sp->numnodes--;
			}
			return(np);
		}
	}
	if(remove)
		return(np);
	if(sp->numnodes==sp->maxnodes)
	{
		sp->maxnodes += 20;
		sp->nodes = (Namval_t**)realloc(sp->nodes,sizeof(Namval_t*)*sp->maxnodes);
	}
	sp->nodes[sp->numnodes++] = np;
	return(np);
}
#endif /* SHOPT_TYPEDEF */

/*
 * given a list of assignments, determine <name> is on the list
   returns a pointer to the argnod on the list or NULL
 */
struct argnod *nv_onlist(struct argnod *arg, const char *name)
{
	char *cp;
	int len = strlen(name);
	for(;arg; arg=arg->argnxt.ap)
	{
		if(*arg->argval==0 && arg->argchn.ap && !(arg->argflag&~(ARG_APPEND|ARG_QUOTED|ARG_MESSAGE)))
			cp = ((struct fornod*)arg->argchn.ap)->fornam;
		else
			cp = arg->argval;
		if(memcmp(cp,name,len)==0 && (cp[len]==0 || cp[len]=='='))
			return(arg);
	}
	return(0);
}

/*
 * Perform parameter assignment for a linked list of parameters
 * <flags> contains attributes for the parameters
 */
void nv_setlist(register struct argnod *arg,register int flags, Namval_t *typ)
{
	Shell_t		*shp = sh_getinterp();
	register char	*cp;
	register Namval_t *np, *mp;
	char		*trap=shp->st.trap[SH_DEBUGTRAP];
	char		*prefix = shp->prefix;
	int		traceon = (sh_isoption(SH_XTRACE)!=0);
	int		array = (flags&(NV_ARRAY|NV_IARRAY));
	Namarr_t	*ap;
	Namval_t	node;
	struct Namref	nr;
#if SHOPT_TYPEDEF
	int		maketype = flags&NV_TYPE;
	struct sh_type	shtp;
	if(maketype)
	{
		shtp.previous = shp->mktype;
		shp->mktype=(void*)&shtp;
		shtp.numnodes=0;
		shtp.maxnodes = 20;
		shtp.rp = 0;
		shtp.nodes =(Namval_t**)malloc(shtp.maxnodes*sizeof(Namval_t*));
	}
#endif /* SHOPT_TYPEDEF*/
#if SHOPT_NAMESPACE
	if(shp->namespace && nv_dict(shp->namespace)==shp->var_tree)
		flags |= NV_NOSCOPE;
#endif /* SHOPT_NAMESPACE */
	flags &= ~(NV_TYPE|NV_ARRAY|NV_IARRAY);
	if(sh_isoption(SH_ALLEXPORT))
		flags |= NV_EXPORT;
	if(shp->prefix)
	{
		flags &= ~(NV_IDENT|NV_EXPORT);
		flags |= NV_VARNAME;
	}
	else
		shp->prefix_root = shp->first_root = 0;
	for(;arg; arg=arg->argnxt.ap)
	{
		shp->used_pos = 0;
		if(arg->argflag&ARG_MAC)
		{
			shp->prefix = 0;
			cp = sh_mactrim(shp,arg->argval,(flags&NV_NOREF)?-3:-1);
			shp->prefix = prefix;
		}
		else
		{
			stakseek(0);
			if(*arg->argval==0 && arg->argchn.ap && !(arg->argflag&~(ARG_APPEND|ARG_QUOTED|ARG_MESSAGE)))
			{
				int flag = (NV_VARNAME|NV_ARRAY|NV_ASSIGN);
				int sub=0;
				struct fornod *fp=(struct fornod*)arg->argchn.ap;
				register Shnode_t *tp=fp->fortre;
				flag |= (flags&(NV_NOSCOPE|NV_STATIC|NV_FARRAY));
				if(arg->argflag&ARG_QUOTED)
					cp = sh_mactrim(shp,fp->fornam,-1);
				else
					cp = fp->fornam;
				error_info.line = fp->fortyp-shp->st.firstline;
				if(!array && tp->tre.tretyp!=TLST && tp->com.comset && !tp->com.comarg && tp->com.comset->argval[0]==0 && tp->com.comset->argval[1]=='[')
					array |= (tp->com.comset->argflag&ARG_MESSAGE)?NV_IARRAY:NV_ARRAY;
				if(prefix && tp->com.comset && *cp=='[')
				{
					shp->prefix = 0;
					np = nv_open(prefix,shp->last_root,flag);
					shp->prefix = prefix;
					if(np)
					{
						if(nv_isvtree(np) && !nv_isarray(np))
						{
							stakputc('.');
							stakputs(cp);
							cp = stakfreeze(1);
						}
						nv_close(np);
					}
				}
				np = nv_open(cp,shp->var_tree,flag|NV_ASSIGN);
				if((arg->argflag&ARG_APPEND) && (tp->tre.tretyp&COMMSK)==TCOM && tp->com.comset && !nv_isvtree(np) && (((ap=nv_arrayptr(np)) && !ap->fun && !nv_opensub(np))  || (!ap && nv_isarray(np) && tp->com.comarg && !((mp=nv_search(tp->com.comarg->argval,shp->fun_tree,0)) && nv_isattr(mp,BLT_DCL)))))
				{
					if(tp->com.comarg)
					{
						struct argnod *ap = tp->com.comset;
						while(ap->argnxt.ap)
							ap = ap->argnxt.ap;
						ap->argnxt.ap = tp->com.comarg;

					}
					tp->com.comarg = tp->com.comset;
					tp->com.comset = 0;
					tp->com.comtyp = COMSCAN;
				}
				if(nv_isattr(np,NV_RDONLY) && np->nvfun && !(flags&NV_RDONLY))
					errormsg(SH_DICT,ERROR_exit(1),e_readonly, nv_name(np));
				if(nv_isattr(np,NV_NOFREE) && nv_isnull(np))
					nv_offattr(np,NV_NOFREE);
				if(nv_istable(np))
					_nv_unset(np,0);
				if(typ && !array  && (!shp->prefix || nv_isnull(np) || nv_isarray(np)))
				{
					if(!(nv_isnull(np)) && !nv_isarray(np))
						_nv_unset(np,0);
					 nv_settype(np,typ,0);
				}
				if((flags&NV_STATIC) && !nv_isattr(np,NV_EXPORT) && !nv_isnull(np))
#if SHOPT_TYPEDEF
					goto check_type;
#else
					continue;
#endif /* SHOPT_TYPEDEF */
				ap=nv_arrayptr(np);
#if SHOPT_FIXEDARRAY
				if(ap && ap->fixed)
					flags |= NV_FARRAY;
#endif /* SHOPT_FIXEDARRAY */
				if(array && (!ap || !ap->hdr.type))
				{
#if SHOPT_FIXEDARRAY
					if(!(arg->argflag&ARG_APPEND) && (!ap || !ap->fixed))
#else
					if(!(arg->argflag&ARG_APPEND))
#endif /* SHOPT_FIXEDARRAY */
						_nv_unset(np,NV_EXPORT);
					if(array&NV_ARRAY)
					{
						nv_setarray(np,nv_associative);
					}
					else
					{
						nv_onattr(np,NV_ARRAY);
					}
				}
				if(array && tp->tre.tretyp!=TLST && !tp->com.comset && !tp->com.comarg)
				{
#if SHOPT_TYPEDEF
						goto check_type;
#else
						continue;
#endif /* SHOPT_TYPEDEF */
				}
				/* check for array assignment */
				if(tp->tre.tretyp!=TLST && tp->com.comarg && !tp->com.comset && ((array&NV_IARRAY) || !((mp=tp->com.comnamp) && nv_isattr(mp,BLT_DCL))))
				{
					int argc;
					Dt_t	*last_root = shp->last_root;
					char **argv = sh_argbuild(shp,&argc,&tp->com,0);
					shp->last_root = last_root;
#if SHOPT_TYPEDEF
					if(shp->mktype && shp->dot_depth==0 && np==((struct sh_type*)shp->mktype)->nodes[0])
					{
						shp->mktype = 0;
						errormsg(SH_DICT,ERROR_exit(1),"%s: not a known type name",argv[0]);
					}
#endif /* SHOPT_TYPEDEF */
					if(!(arg->argflag&ARG_APPEND))
					{
#if SHOPT_FIXEDARRAY
						if(!nv_isarray(np) || ((ap=nv_arrayptr(np)) && !ap->fixed && (ap->nelem&ARRAY_MASK)))
#else
						if(!nv_isarray(np) || ((ap=nv_arrayptr(np)) && (ap->nelem&ARRAY_MASK)))
#endif /* SHOPT_FIXEDARRAY */
						{
							if(ap)
								ap->nelem |= ARRAY_UNDEF;
							_nv_unset(np,NV_EXPORT);
						}
					}
					nv_setvec(np,(arg->argflag&ARG_APPEND),argc,argv);
					if(traceon || trap)
					{
						int n = -1;
						char *name = nv_name(np);
						if(arg->argflag&ARG_APPEND)
							n = '+';
						if(trap)
							sh_debug(shp,trap,name,(char*)0,argv,(arg->argflag&ARG_APPEND)|ARG_ASSIGN);
						if(traceon)
						{
							sh_trace(shp,NIL(char**),0);
							sfputr(sfstderr,name,n);
							sfwrite(sfstderr,"=( ",3);
							while(cp= *argv++)
								sfputr(sfstderr,sh_fmtq(cp),' ');
							sfwrite(sfstderr,")\n",2);
						}
					}
#if SHOPT_TYPEDEF
					goto check_type;
#else
					continue;
#endif /* SHOPT_TYPEDEF */
				}
				if((tp->tre.tretyp&COMMSK)==TFUN)
					goto skip;
				if(tp->tre.tretyp==0 && !tp->com.comset && !tp->com.comarg)
				{
					if(!(arg->argflag&ARG_APPEND) && nv_isattr(np,NV_BINARY|NV_NOFREE|NV_RAW)!=(NV_BINARY|NV_NOFREE|NV_RAW))
						_nv_unset(np,NV_EXPORT);
					goto skip;
				}
				if(tp->tre.tretyp==TLST || !tp->com.comset || tp->com.comset->argval[0]!='[')
				{
					if(tp->tre.tretyp!=TLST && !tp->com.comnamp && tp->com.comset && tp->com.comset->argval[0]==0 && tp->com.comset->argchn.ap)
					{
						if(prefix || np)
							cp = stakcopy(nv_name(np));
						shp->prefix = cp;
						if(tp->com.comset->argval[1]=='[')
						{
							if((arg->argflag&ARG_APPEND) && (!nv_isarray(np) || (nv_aindex(np)>=0)))
								_nv_unset(np,0);
							if(!(array&NV_IARRAY) && !(tp->com.comset->argflag&ARG_MESSAGE))
								nv_setarray(np,nv_associative);
						}
						nv_setlist(tp->com.comset,flags&~NV_STATIC,0);
						shp->prefix = prefix;
						if(tp->com.comset->argval[1]!='[')
							 nv_setvtree(np);
						nv_close(np);
#if SHOPT_TYPEDEF
						goto check_type;
#else
						continue;
#endif /* SHOPT_TYPEDEF */
					}
					if(*cp!='.' && *cp!='[' && strchr(cp,'['))
					{
						cp = stakcopy(nv_name(np));
						nv_close(np);
						if(!(arg->argflag&ARG_APPEND))
							flag &= ~NV_ARRAY;
						shp->prefix_root = shp->first_root;
						np = nv_open(cp,shp->prefix_root?shp->prefix_root:shp->var_tree,flag);
					}
					if(arg->argflag&ARG_APPEND)
					{
						if(nv_isarray(np))
						{
							if((sub=nv_aimax(np)) < 0  && nv_arrayptr(np))
								errormsg(SH_DICT,ERROR_exit(1),e_badappend,nv_name(np));
							if(sub>=0)
								sub++;
						}
						if(!nv_isnull(np) && np->nvalue.cp!=Empty && !nv_isvtree(np))
							sub=1;
					}
					else if(((np->nvalue.cp && np->nvalue.cp!=Empty)||nv_isvtree(np)|| nv_arrayptr(np)) && !nv_type(np))
					{
						_nv_unset(np,NV_EXPORT);
						if(ap && ap->fun)
							 nv_setarray(np,nv_associative);

					}
				}
				else
				{
					if(!(arg->argflag&ARG_APPEND))
						_nv_unset(np,NV_EXPORT);
					if(!sh_isoption(SH_BASH) && !(array&NV_IARRAY) && !nv_isarray(np))
						nv_setarray(np,nv_associative);
				}
			skip:
				if(sub>0)
				{
					sfprintf(stkstd,"%s[%d]",prefix?nv_name(np):cp,sub);
					shp->prefix = stakfreeze(1);
					nv_putsub(np,(char*)0,ARRAY_ADD|ARRAY_FILL|sub);
				}
				else if(prefix)
					shp->prefix = stakcopy(nv_name(np));
				else
					shp->prefix = cp;
				shp->last_table = 0;
				if(shp->prefix)
				{
					if(*shp->prefix=='_' && shp->prefix[1]=='.' && nv_isref(L_ARGNOD))
					{
						sfprintf(stkstd,"%s%s",nv_name(L_ARGNOD->nvalue.nrp->np),shp->prefix+1);
						shp->prefix = stkfreeze(stkstd,1);
					}
					memset(&nr,0,sizeof(nr));
					memcpy(&node,L_ARGNOD,sizeof(node));
					L_ARGNOD->nvalue.nrp = &nr;
					nr.np = np;
					nr.root = shp->last_root;
					nr.table = shp->last_table;
					L_ARGNOD->nvflag = NV_REF|NV_NOFREE;
					L_ARGNOD->nvfun = 0;
				}
				sh_exec(tp,sh_isstate(SH_ERREXIT));
#if SHOPT_TYPEDEF
				if(shp->prefix)
#endif
				{
					L_ARGNOD->nvalue.nrp = node.nvalue.nrp;
					L_ARGNOD->nvflag = node.nvflag;
					L_ARGNOD->nvfun = node.nvfun;
				}
				shp->prefix = prefix;
				if(nv_isarray(np) && (mp=nv_opensub(np)))
					np = mp;
				while(tp->tre.tretyp==TLST)
				{
					if(!tp->lst.lstlef || !tp->lst.lstlef->tre.tretyp==TCOM || tp->lst.lstlef->com.comarg || tp->lst.lstlef->com.comset && tp->lst.lstlef->com.comset->argval[0]!='[')
						break;
					tp = tp->lst.lstrit;

				}
				if(!nv_isarray(np) && !typ && (tp->com.comarg || !tp->com.comset || tp->com.comset->argval[0]!='['))
				{
					nv_setvtree(np);
					if(tp->com.comarg || tp->com.comset)
						np->nvfun->dsize = 0;
				}
#if SHOPT_TYPEDEF
				goto check_type;
#else
				continue;
#endif /* SHOPT_TYPEDEF */
			}
			cp = arg->argval;
			mp = 0;
		}
		np = nv_open(cp,shp->prefix_root?shp->prefix_root:shp->var_tree,flags);
		if(!np->nvfun && (flags&NV_NOREF))
		{
			if(shp->used_pos)
				nv_onattr(np,NV_PARAM);
			else
				nv_offattr(np,NV_PARAM);
		}
		if(traceon || trap)
		{
			register char *sp=cp;
			char *name=nv_name(np);
			char *sub=0;
			int append = 0;
			if(nv_isarray(np))
				sub = savesub;
			if(cp=lastdot(sp,'='))
			{
				if(cp[-1]=='+')
					append = ARG_APPEND;
				cp++;
			}
			if(traceon)
			{
				sh_trace(shp,NIL(char**),0);
				nv_outname(sfstderr,name,-1);
				if(sub)
					sfprintf(sfstderr,"[%s]",sh_fmtq(sub));
				if(cp)
				{
					if(append)
						sfputc(sfstderr,'+');
					sfprintf(sfstderr,"=%s\n",sh_fmtq(cp));
				}
			}
			if(trap)
			{
					char *av[2];
					av[0] = cp;
					av[1] = 0;
					sh_debug(shp,trap,name,sub,av,append);
			}
		}
#if SHOPT_TYPEDEF
	check_type:
		if(maketype)
		{
			nv_open(shtp.nodes[0]->nvname,shp->var_tree,NV_ASSIGN|NV_VARNAME|NV_NOADD|NV_NOFAIL);
			np = nv_mktype(shtp.nodes,shtp.numnodes);
			free((void*)shtp.nodes);
			shp->mktype = shtp.previous;
			maketype = 0;
			if(shp->namespace)
				free(shp->prefix);
			shp->prefix = 0;
			if(nr.np == np)
			{
				L_ARGNOD->nvalue.nrp = node.nvalue.nrp;
				L_ARGNOD->nvflag = node.nvflag;
				L_ARGNOD->nvfun = node.nvfun;
			}
		}
#endif /* SHOPT_TYPEDEF */
	}
}

/*
 * copy the subscript onto the stack
 */
static void stak_subscript(const char *sub, int last)
{
	register int c;
	stakputc('[');
	while(c= *sub++)
	{
		if(c=='[' || c==']' || c=='\\')
			stakputc('\\');
		stakputc(c);
	}
	stakputc(last);
}

/*
 * construct a new name from a prefix and base name on the stack
 */
static char *copystack(const char *prefix, register const char *name, const char *sub)
{
	register int last=0,offset = staktell();
	if(prefix)
	{
		stakputs(prefix);
		if(*stakptr(staktell()-1)=='.')
			stakseek(staktell()-1);
		if(*name=='.' && name[1]=='[')
			last = staktell()+2;
		if(*name!='['  && *name!='.' && *name!='=' && *name!='+')
			stakputc('.');
		if(*name=='.' && (name[1]=='=' || name[1]==0))
			stakputc('.');
	}
	if(last)
	{
		stakputs(name);
		if(sh_checkid(stakptr(last),(char*)0))
			stakseek(staktell()-2);
	}
	if(sub)
		stak_subscript(sub,']');
	if(!last)
		stakputs(name);
	stakputc(0);
	return(stakptr(offset));
}

/*
 * grow this stack string <name> by <n> bytes and move from cp-1 to end
 * right by <n>.  Returns beginning of string on the stack
 */
static char *stack_extend(const char *cname, char *cp, int n)
{
	register char *name = (char*)cname;
	int offset = name - stakptr(0);
	int m = cp-name;
	stakseek(offset + strlen(name)+n+1);
	name = stakptr(offset);
	cp =  name + m;
	m = strlen(cp)+1;
	while(m-->0)
		cp[n+m]=cp[m];
	return((char*)name);
}

Namval_t *nv_create(const char *name,  Dt_t *root, int flags, Namfun_t *dp)
{
	Shell_t			*shp = sh_getinterp();
	char			*sub=0, *cp=(char*)name, *sp, *xp;
	register int		c;
	register Namval_t	*np=0, *nq=0;
	Namfun_t		*fp=0;
	long			mode, add=0;
	int			copy=0,isref,top=0,noscope=(flags&NV_NOSCOPE);
	int			nofree=0, level=0;
#if SHOPT_FIXEDARRAY
	Namarr_t		*ap;
#endif /* SHOPT_FIXEDARRAY */
	if(root==shp->var_tree)
	{
		if(dtvnext(root))
			top = 1;
		else
			flags &= ~NV_NOSCOPE;
	}
	if(!dp->disc)
		copy = dp->nofree&1;
	if(*cp=='.')
		cp++;
	while(1)
	{
		switch(c = *(unsigned char*)(sp = cp))
		{
		    case '[':
			if(flags&NV_NOARRAY)
			{
				dp->last = cp;
				return(np);
			}
			cp = nv_endsubscript((Namval_t*)0,sp,0);
			if(sp==name || sp[-1]=='.')
				c = *(sp = cp);
			goto skip;
		    case '.':
			if(flags&NV_IDENT)
				return(0);
			if(root==shp->var_tree)
				flags &= ~NV_EXPORT;
			if(!copy && !(flags&NV_NOREF))
			{
				c = sp-name;
				copy = cp-name;
				dp->nofree |= 1;
				name = copystack((const char*)0, name,(const char*)0);
				cp = (char*)name+copy;
				sp = (char*)name+c;
				c = '.';
			}
			/* FALLTHROUGH */
		skip:
		    case '+':
		    case '=':
			*sp = 0;
			/* FALLTHROUGH */
		    case 0:
			isref = 0;
			dp->last = cp;
			mode =  (c=='.' || (flags&NV_NOADD))?add:NV_ADD;
			if(level++ || ((flags&NV_NOSCOPE) && c!='.'))
				mode |= HASH_NOSCOPE;
			np=0;
			if(top)
			{
				struct Ufunction *rp;
				if((rp=shp->st.real_fun) && !rp->sdict && (flags&NV_STATIC))
				{
					Dt_t *dp = dtview(shp->var_tree,(Dt_t*)0);
					rp->sdict = dtopen(&_Nvdisc,Dtoset);
					dtview(rp->sdict,dp);
					dtview(shp->var_tree,rp->sdict);
				}
				if(np = nv_search(name,shp->var_tree,0))
				{
#if SHOPT_NAMESPACE
					if(shp->var_tree->walk==shp->var_base || (shp->var_tree->walk!=shp->var_tree && shp->namespace &&  nv_dict(shp->namespace)==shp->var_tree->walk))
#else
					if(shp->var_tree->walk==shp->var_base)
#endif /* SHOPT_NAMESPACE */
					{
#if SHOPT_NAMESPACE
						if(!(nq = nv_search((char*)np,shp->var_base,HASH_BUCKET)))
#endif /* SHOPT_NAMESPACE */
						nq = np;
						shp->last_root = shp->var_tree->walk;
						if((flags&NV_NOSCOPE) && *cp!='.')
						{
							if(mode==0)
								root = shp->var_tree->walk;
							else
							{
								nv_delete(np,(Dt_t*)0,NV_NOFREE);
								np = 0;
							}
						}
					}
					else
					{
						if(shp->var_tree->walk)
							root = shp->var_tree->walk;
						flags |= NV_NOSCOPE;
						noscope = 1;
					}
				}
				if(rp && rp->sdict && (flags&NV_STATIC))
				{
					root = rp->sdict;
					if(np && shp->var_tree->walk==shp->var_tree)
					{
						_nv_unset(np,0);
						nv_delete(np,shp->var_tree,0);
						np = 0;
					}
					if(!np || shp->var_tree->walk!=root)
						np =  nv_search(name,root,HASH_NOSCOPE|NV_ADD);
				}
			}
#if SHOPT_NAMESPACE
			if(!np && !noscope && *name!='.' && shp->namespace && root==shp->var_tree)
				root = nv_dict(shp->namespace);
#endif /* SHOPT_NAMESPACE */
			if(np ||  (np = nv_search(name,root,mode)))
			{
				isref = nv_isref(np);
				shp->openmatch = root->walk?root->walk:root;
				if(top)
				{
					if(nq==np)
					{
						flags &= ~NV_NOSCOPE;
						root = shp->last_root;
					}
					else if(nq)
					{
						if(nv_isnull(np) && c!='.' && ((np->nvfun=nv_cover(nq)) || nq==OPTINDNOD))
						{
							np->nvname = nq->nvname;
#if SHOPT_NAMESPACE
							if(shp->namespace && nv_dict(shp->namespace)==shp->var_tree && nv_isattr(nq,NV_EXPORT))
								nv_onattr(np,NV_EXPORT);
#endif /* SHOPT_NAMESPACE */
							if(nq==OPTINDNOD)
							{
								np->nvfun = nq->nvfun;
								np->nvalue.lp = (&shp->st.optindex);
								nv_onattr(np,NV_INTEGER|NV_NOFREE);
							}
						}
						flags |= NV_NOSCOPE;
					}
				}
				else if(add && nv_isnull(np) && c=='.' && cp[1]!='.')
					nv_setvtree(np);
#if SHOPT_NAMESPACE
				if(shp->namespace && root==nv_dict(shp->namespace))
				{
					flags |= NV_NOSCOPE;
					shp->last_table = shp->namespace;
				}
#endif /* SHOPT_NAMESPACE */
			}
			if(c)
				*sp = c;
			top = 0;
			if(isref)
			{
#if SHOPT_FIXEDARRAY
				int n=0,dim;
#endif /* SHOPT_FIXEDARRAY */
#if NVCACHE
				nvcache.ok = 0;
#endif
				if(c=='.') /* don't optimize */
					shp->argaddr = 0;
				else if((flags&NV_NOREF) && (c!='[' && *cp!='.'))
				{
					if(c && !(flags&NV_NOADD))
						nv_unref(np);
					return(np);
				}
				while(nv_isref(np) && np->nvalue.cp)
				{
					root = nv_reftree(np);
					shp->last_root = root;
					shp->last_table = nv_reftable(np);
					sub = nv_refsub(np);
#if SHOPT_FIXEDARRAY
					n = nv_refindex(np);
					dim = nv_refdimen(np);
#endif /* SHOPT_FIXEDARRAY */
					np = nv_refnode(np);
#if SHOPT_FIXEDARRAY
					if(n)
					{
						ap = nv_arrayptr(np);
						ap->nelem = dim;
						nv_putsub(np,(char*)0,n);
					}
					else
#endif /* SHOPT_FIXEDARRAY */
					if(sub && c!='.')
						nv_putsub(np,sub,0L);
					flags |= NV_NOSCOPE;
					noscope = 1;
				}