/commands/make/var.c

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/*	$NetBSD: var.c,v 1.159 2010/06/06 01:13:12 sjg Exp $	*/

/*
 * Copyright (c) 1988, 1989, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Copyright (c) 1989 by Berkeley Softworks
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef MAKE_NATIVE
static char rcsid[] = "$NetBSD: var.c,v 1.159 2010/06/06 01:13:12 sjg Exp $";
#else
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 3/19/94";
#else
__RCSID("$NetBSD: var.c,v 1.159 2010/06/06 01:13:12 sjg Exp $");
#endif
#endif /* not lint */
#endif

/*-
 * var.c --
 *	Variable-handling functions
 *
 * Interface:
 *	Var_Set		    Set the value of a variable in the given
 *			    context. The variable is created if it doesn't
 *			    yet exist. The value and variable name need not
 *			    be preserved.
 *
 *	Var_Append	    Append more characters to an existing variable
 *			    in the given context. The variable needn't
 *			    exist already -- it will be created if it doesn't.
 *			    A space is placed between the old value and the
 *			    new one.
 *
 *	Var_Exists	    See if a variable exists.
 *
 *	Var_Value 	    Return the value of a variable in a context or
 *			    NULL if the variable is undefined.
 *
 *	Var_Subst 	    Substitute named variable, or all variables if
 *			    NULL in a string using
 *			    the given context as the top-most one. If the
 *			    third argument is non-zero, Parse_Error is
 *			    called if any variables are undefined.
 *
 *	Var_Parse 	    Parse a variable expansion from a string and
 *			    return the result and the number of characters
 *			    consumed.
 *
 *	Var_Delete	    Delete a variable in a context.
 *
 *	Var_Init  	    Initialize this module.
 *
 * Debugging:
 *	Var_Dump  	    Print out all variables defined in the given
 *			    context.
 *
 * XXX: There's a lot of duplication in these functions.
 */

#include    <sys/stat.h>
#ifndef NO_REGEX
#include    <sys/types.h>
#include    <regex.h>
#endif
#include    <ctype.h>
#include    <stdlib.h>
#include    <limits.h>

#include    "make.h"
#include    "buf.h"
#include    "dir.h"
#include    "job.h"

/*
 * This is a harmless return value for Var_Parse that can be used by Var_Subst
 * to determine if there was an error in parsing -- easier than returning
 * a flag, as things outside this module don't give a hoot.
 */
char 	var_Error[] = "";

/*
 * Similar to var_Error, but returned when the 'errnum' flag for Var_Parse is
 * set false. Why not just use a constant? Well, gcc likes to condense
 * identical string instances...
 */
static char	varNoError[] = "";

/*
 * Internally, variables are contained in four different contexts.
 *	1) the environment. They may not be changed. If an environment
 *	    variable is appended-to, the result is placed in the global
 *	    context.
 *	2) the global context. Variables set in the Makefile are located in
 *	    the global context. It is the penultimate context searched when
 *	    substituting.
 *	3) the command-line context. All variables set on the command line
 *	   are placed in this context. They are UNALTERABLE once placed here.
 *	4) the local context. Each target has associated with it a context
 *	   list. On this list are located the structures describing such
 *	   local variables as $(@) and $(*)
 * The four contexts are searched in the reverse order from which they are
 * listed.
 */
GNode          *VAR_GLOBAL;   /* variables from the makefile */
GNode          *VAR_CMD;      /* variables defined on the command-line */

#define FIND_CMD	0x1   /* look in VAR_CMD when searching */
#define FIND_GLOBAL	0x2   /* look in VAR_GLOBAL as well */
#define FIND_ENV  	0x4   /* look in the environment also */

typedef struct Var {
    char          *name;	/* the variable's name */
    Buffer	  val;		/* its value */
    int		  flags;    	/* miscellaneous status flags */
#define VAR_IN_USE	1   	    /* Variable's value currently being used.
				     * Used to avoid recursion */
#define VAR_FROM_ENV	2   	    /* Variable comes from the environment */
#define VAR_JUNK  	4   	    /* Variable is a junk variable that
				     * should be destroyed when done with
				     * it. Used by Var_Parse for undefined,
				     * modified variables */
#define VAR_KEEP	8	    /* Variable is VAR_JUNK, but we found
				     * a use for it in some modifier and
				     * the value is therefore valid */
#define VAR_EXPORTED	16 	    /* Variable is exported */
#define VAR_REEXPORT	32	    /* Indicate if var needs re-export.
				     * This would be true if it contains $'s
				     */
#define VAR_FROM_CMD	64 	    /* Variable came from command line */
}  Var;

/*
 * Exporting vars is expensive so skip it if we can
 */
#define VAR_EXPORTED_NONE	0
#define VAR_EXPORTED_YES	1
#define VAR_EXPORTED_ALL	2
static int var_exportedVars = VAR_EXPORTED_NONE;
/*
 * We pass this to Var_Export when doing the initial export
 * or after updating an exported var.
 */
#define VAR_EXPORT_PARENT 1

/* Var*Pattern flags */
#define VAR_SUB_GLOBAL	0x01	/* Apply substitution globally */
#define VAR_SUB_ONE	0x02	/* Apply substitution to one word */
#define VAR_SUB_MATCHED	0x04	/* There was a match */
#define VAR_MATCH_START	0x08	/* Match at start of word */
#define VAR_MATCH_END	0x10	/* Match at end of word */
#define VAR_NOSUBST	0x20	/* don't expand vars in VarGetPattern */

/* Var_Set flags */
#define VAR_NO_EXPORT	0x01	/* do not export */

typedef struct {
    /*
     * The following fields are set by Var_Parse() when it
     * encounters modifiers that need to keep state for use by
     * subsequent modifiers within the same variable expansion.
     */
    Byte	varSpace;	/* Word separator in expansions */
    Boolean	oneBigWord;	/* TRUE if we will treat the variable as a
				 * single big word, even if it contains
				 * embedded spaces (as opposed to the
				 * usual behaviour of treating it as
				 * several space-separated words). */
} Var_Parse_State;

/* struct passed as 'void *' to VarSubstitute() for ":S/lhs/rhs/",
 * to VarSYSVMatch() for ":lhs=rhs". */
typedef struct {
    const char   *lhs;	    /* String to match */
    int		  leftLen; /* Length of string */
    const char   *rhs;	    /* Replacement string (w/ &'s removed) */
    int		  rightLen; /* Length of replacement */
    int		  flags;
} VarPattern;

/* struct passed as 'void *' to VarLoopExpand() for ":@tvar@str@" */
typedef struct {
    GNode	*ctxt;		/* variable context */
    char	*tvar;		/* name of temp var */
    int		tvarLen;
    char	*str;		/* string to expand */
    int		strLen;
    int		errnum;		/* errnum for not defined */
} VarLoop_t;

#ifndef NO_REGEX
/* struct passed as 'void *' to VarRESubstitute() for ":C///" */
typedef struct {
    regex_t	   re;
    int		   nsub;
    regmatch_t 	  *matches;
    char 	  *replace;
    int		   flags;
} VarREPattern;
#endif

/* struct passed to VarSelectWords() for ":[start..end]" */
typedef struct {
    int		start;		/* first word to select */
    int		end;		/* last word to select */
} VarSelectWords_t;

static Var *VarFind(const char *, GNode *, int);
static void VarAdd(const char *, const char *, GNode *);
static Boolean VarHead(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
static Boolean VarTail(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
static Boolean VarSuffix(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
static Boolean VarRoot(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
static Boolean VarMatch(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
#ifdef SYSVVARSUB
static Boolean VarSYSVMatch(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
#endif
static Boolean VarNoMatch(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
#ifndef NO_REGEX
static void VarREError(int, regex_t *, const char *);
static Boolean VarRESubstitute(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
#endif
static Boolean VarSubstitute(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
static Boolean VarLoopExpand(GNode *, Var_Parse_State *,
			char *, Boolean, Buffer *, void *);
static char *VarGetPattern(GNode *, Var_Parse_State *,
			   int, const char **, int, int *, int *,
			   VarPattern *);
static char *VarQuote(char *);
static char *VarChangeCase(char *, int);
static char *VarModify(GNode *, Var_Parse_State *,
    const char *,
    Boolean (*)(GNode *, Var_Parse_State *, char *, Boolean, Buffer *, void *),
    void *);
static char *VarOrder(const char *, const char);
static char *VarUniq(const char *);
static int VarWordCompare(const void *, const void *);
static void VarPrintVar(void *);

#define BROPEN	'{'
#define BRCLOSE	'}'
#define PROPEN	'('
#define PRCLOSE	')'

/*-
 *-----------------------------------------------------------------------
 * VarFind --
 *	Find the given variable in the given context and any other contexts
 *	indicated.
 *
 * Input:
 *	name		name to find
 *	ctxt		context in which to find it
 *	flags		FIND_GLOBAL set means to look in the
 *			VAR_GLOBAL context as well. FIND_CMD set means
 *			to look in the VAR_CMD context also. FIND_ENV
 *			set means to look in the environment
 *
 * Results:
 *	A pointer to the structure describing the desired variable or
 *	NULL if the variable does not exist.
 *
 * Side Effects:
 *	None
 *-----------------------------------------------------------------------
 */
static Var *
VarFind(const char *name, GNode *ctxt, int flags)
{
    Hash_Entry         	*var;
    Var			*v;

	/*
	 * If the variable name begins with a '.', it could very well be one of
	 * the local ones.  We check the name against all the local variables
	 * and substitute the short version in for 'name' if it matches one of
	 * them.
	 */
	if (*name == '.' && isupper((unsigned char) name[1]))
		switch (name[1]) {
		case 'A':
			if (!strcmp(name, ".ALLSRC"))
				name = ALLSRC;
			if (!strcmp(name, ".ARCHIVE"))
				name = ARCHIVE;
			break;
		case 'I':
			if (!strcmp(name, ".IMPSRC"))
				name = IMPSRC;
			break;
		case 'M':
			if (!strcmp(name, ".MEMBER"))
				name = MEMBER;
			break;
		case 'O':
			if (!strcmp(name, ".OODATE"))
				name = OODATE;
			break;
		case 'P':
			if (!strcmp(name, ".PREFIX"))
				name = PREFIX;
			break;
		case 'T':
			if (!strcmp(name, ".TARGET"))
				name = TARGET;
			break;
		}
    /*
     * First look for the variable in the given context. If it's not there,
     * look for it in VAR_CMD, VAR_GLOBAL and the environment, in that order,
     * depending on the FIND_* flags in 'flags'
     */
    var = Hash_FindEntry(&ctxt->context, name);

    if ((var == NULL) && (flags & FIND_CMD) && (ctxt != VAR_CMD)) {
	var = Hash_FindEntry(&VAR_CMD->context, name);
    }
    if (!checkEnvFirst && (var == NULL) && (flags & FIND_GLOBAL) &&
	(ctxt != VAR_GLOBAL))
    {
	var = Hash_FindEntry(&VAR_GLOBAL->context, name);
    }
    if ((var == NULL) && (flags & FIND_ENV)) {
	char *env;

	if ((env = getenv(name)) != NULL) {
	    int		len;

	    v = bmake_malloc(sizeof(Var));
	    v->name = bmake_strdup(name);

	    len = strlen(env);

	    Buf_Init(&v->val, len + 1);
	    Buf_AddBytes(&v->val, len, env);

	    v->flags = VAR_FROM_ENV;
	    return (v);
	} else if (checkEnvFirst && (flags & FIND_GLOBAL) &&
		   (ctxt != VAR_GLOBAL))
	{
	    var = Hash_FindEntry(&VAR_GLOBAL->context, name);
	    if (var == NULL) {
		return NULL;
	    } else {
		return ((Var *)Hash_GetValue(var));
	    }
	} else {
	    return NULL;
	}
    } else if (var == NULL) {
	return NULL;
    } else {
	return ((Var *)Hash_GetValue(var));
    }
}

/*-
 *-----------------------------------------------------------------------
 * VarFreeEnv  --
 *	If the variable is an environment variable, free it
 *
 * Input:
 *	v		the variable
 *	destroy		true if the value buffer should be destroyed.
 *
 * Results:
 *	1 if it is an environment variable 0 ow.
 *
 * Side Effects:
 *	The variable is free'ed if it is an environent variable.
 *-----------------------------------------------------------------------
 */
static Boolean
VarFreeEnv(Var *v, Boolean destroy)
{
    if ((v->flags & VAR_FROM_ENV) == 0)
	return FALSE;
    free(v->name);
    Buf_Destroy(&v->val, destroy);
    free(v);
    return TRUE;
}

/*-
 *-----------------------------------------------------------------------
 * VarAdd  --
 *	Add a new variable of name name and value val to the given context
 *
 * Input:
 *	name		name of variable to add
 *	val		value to set it to
 *	ctxt		context in which to set it
 *
 * Results:
 *	None
 *
 * Side Effects:
 *	The new variable is placed at the front of the given context
 *	The name and val arguments are duplicated so they may
 *	safely be freed.
 *-----------------------------------------------------------------------
 */
static void
VarAdd(const char *name, const char *val, GNode *ctxt)
{
    Var   	  *v;
    int		  len;
    Hash_Entry    *h;

    v = bmake_malloc(sizeof(Var));

    len = val ? strlen(val) : 0;
    Buf_Init(&v->val, len+1);
    Buf_AddBytes(&v->val, len, val);

    v->flags = 0;

    h = Hash_CreateEntry(&ctxt->context, name, NULL);
    Hash_SetValue(h, v);
    v->name = h->name;
    if (DEBUG(VAR)) {
	fprintf(debug_file, "%s:%s = %s\n", ctxt->name, name, val);
    }
}

/*-
 *-----------------------------------------------------------------------
 * Var_Delete --
 *	Remove a variable from a context.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The Var structure is removed and freed.
 *
 *-----------------------------------------------------------------------
 */
void
Var_Delete(const char *name, GNode *ctxt)
{
    Hash_Entry 	  *ln;

    ln = Hash_FindEntry(&ctxt->context, name);
    if (DEBUG(VAR)) {
	fprintf(debug_file, "%s:delete %s%s\n",
	    ctxt->name, name, ln ? "" : " (not found)");
    }
    if (ln != NULL) {
	Var 	  *v;

	v = (Var *)Hash_GetValue(ln);
	if ((v->flags & VAR_EXPORTED)) {
	    unsetenv(v->name);
	}
	if (strcmp(MAKE_EXPORTED, v->name) == 0) {
	    var_exportedVars = VAR_EXPORTED_NONE;
	}
	if (v->name != ln->name)
		free(v->name);
	Hash_DeleteEntry(&ctxt->context, ln);
	Buf_Destroy(&v->val, TRUE);
	free(v);
    }
}


/*
 * Export a var.
 * We ignore make internal variables (those which start with '.')
 * Also we jump through some hoops to avoid calling setenv
 * more than necessary since it can leak.
 * We only manipulate flags of vars if 'parent' is set.
 */
static int
Var_Export1(const char *name, int parent)
{
    char tmp[BUFSIZ];
    Var *v;
    char *val = NULL;
    int n;

    if (*name == '.')
	return 0;			/* skip internals */
    if (!name[1]) {
	/*
	 * A single char.
	 * If it is one of the vars that should only appear in
	 * local context, skip it, else we can get Var_Subst
	 * into a loop.
	 */
	switch (name[0]) {
	case '@':
	case '%':
	case '*':
	case '!':
	    return 0;
	}
    }
    v = VarFind(name, VAR_GLOBAL, 0);
    if (v == NULL) {
	return 0;
    }
    if (!parent &&
	(v->flags & (VAR_EXPORTED|VAR_REEXPORT)) == VAR_EXPORTED) {
	return 0;			/* nothing to do */
    }
    val = Buf_GetAll(&v->val, NULL);
    if (strchr(val, '$')) {
	if (parent) {
	    /*
	     * Flag this as something we need to re-export.
	     * No point actually exporting it now though,
	     * the child can do it at the last minute.
	     */
	    v->flags |= (VAR_EXPORTED|VAR_REEXPORT);
	    return 1;
	}
	if (v->flags & VAR_IN_USE) {
	    /*
	     * We recursed while exporting in a child.
	     * This isn't going to end well, just skip it.
	     */
	    return 0;
	}
	n = snprintf(tmp, sizeof(tmp), "${%s}", name);
	if (n < (int)sizeof(tmp)) {
	    val = Var_Subst(NULL, tmp, VAR_GLOBAL, 0);
	    setenv(name, val, 1);
	    free(val);
	}
    } else {
	if (parent) {
	    v->flags &= ~VAR_REEXPORT;	/* once will do */
	}
	if (parent || !(v->flags & VAR_EXPORTED)) {
	    setenv(name, val, 1);
	}
    }
    /*
     * This is so Var_Set knows to call Var_Export again...
     */
    if (parent) {
	v->flags |= VAR_EXPORTED;
    }
    return 1;
}

/*
 * This gets called from our children.
 */
void
Var_ExportVars(void)
{
    char tmp[BUFSIZ];
    Hash_Entry         	*var;
    Hash_Search 	state;
    Var *v;
    char *val;
    int n;

    if (VAR_EXPORTED_NONE == var_exportedVars)
	return;

    if (VAR_EXPORTED_ALL == var_exportedVars) {
	/*
	 * Ouch! This is crazy...
	 */
	for (var = Hash_EnumFirst(&VAR_GLOBAL->context, &state);
	     var != NULL;
	     var = Hash_EnumNext(&state)) {
	    v = (Var *)Hash_GetValue(var);
	    Var_Export1(v->name, 0);
	}
	return;
    }
    /*
     * We have a number of exported vars,
     */
    n = snprintf(tmp, sizeof(tmp), "${" MAKE_EXPORTED ":O:u}");
    if (n < (int)sizeof(tmp)) {
	char **av;
	char *as;
	int ac;
	int i;

	val = Var_Subst(NULL, tmp, VAR_GLOBAL, 0);
	av = brk_string(val, &ac, FALSE, &as);
	for (i = 0; i < ac; i++) {
	    Var_Export1(av[i], 0);
	}
	free(val);
	free(as);
	free(av);
    }
}

/*
 * This is called when .export is seen or
 * .MAKE.EXPORTED is modified.
 * It is also called when any exported var is modified.
 */
void
Var_Export(char *str, int isExport)
{
    char *name;
    char *val;
    char **av;
    char *as;
    int track;
    int ac;
    int i;

    if (isExport && (!str || !str[0])) {
	var_exportedVars = VAR_EXPORTED_ALL; /* use with caution! */
	return;
    }

    if (strncmp(str, "-env", 4) == 0) {
	track = 0;
	str += 4;
    } else {
	track = VAR_EXPORT_PARENT;
    }
    val = Var_Subst(NULL, str, VAR_GLOBAL, 0);
    av = brk_string(val, &ac, FALSE, &as);
    for (i = 0; i < ac; i++) {
	name = av[i];
	if (!name[1]) {
	    /*
	     * A single char.
	     * If it is one of the vars that should only appear in
	     * local context, skip it, else we can get Var_Subst
	     * into a loop.
	     */
	    switch (name[0]) {
	    case '@':
	    case '%':
	    case '*':
	    case '!':
		continue;
	    }
	}
	if (Var_Export1(name, track)) {
	    if (VAR_EXPORTED_ALL != var_exportedVars)
		var_exportedVars = VAR_EXPORTED_YES;
	    if (isExport && track) {
		Var_Append(MAKE_EXPORTED, name, VAR_GLOBAL);
	    }
	}
    }
    free(val);
    free(as);
    free(av);
}


/*
 * This is called when .unexport[-env] is seen.
 */
void
Var_UnExport(char *str)
{
    char tmp[BUFSIZ];
    char *vlist;
    char *cp;
    Boolean unexport_env;
    int n;

    if (!str || !str[0]) {
	return; 			/* assert? */
    }

    vlist = NULL;

    str += 8;
    unexport_env = (strncmp(str, "-env", 4) == 0);
    if (unexport_env) {
	extern char **environ;
	static char **savenv;
	char **newenv;

	cp = getenv(MAKE_LEVEL);	/* we should preserve this */
	if (environ == savenv) {
	    /* we have been here before! */
	    newenv = bmake_realloc(environ, 2 * sizeof(char *));
	} else {
	    if (savenv) {
		free(savenv);
		savenv = NULL;
	    }
	    newenv = bmake_malloc(2 * sizeof(char *));
	}
	if (!newenv)
	    return;
	/* Note: we cannot safely free() the original environ. */
	environ = savenv = newenv;
	newenv[0] = NULL;
	newenv[1] = NULL;
	setenv(MAKE_LEVEL, cp, 1);
    } else {
	for (; *str != '\n' && isspace((unsigned char) *str); str++)
	    continue;
	if (str[0] && str[0] != '\n') {
	    vlist = str;
	}
    }

    if (!vlist) {
	/* Using .MAKE.EXPORTED */
	n = snprintf(tmp, sizeof(tmp), "${" MAKE_EXPORTED ":O:u}");
	if (n < (int)sizeof(tmp)) {
	    vlist = Var_Subst(NULL, tmp, VAR_GLOBAL, 0);
	}
    }
    if (vlist) {
	Var *v;
	char **av;
	char *as;
	int ac;
	int i;

	av = brk_string(vlist, &ac, FALSE, &as);
	for (i = 0; i < ac; i++) {
	    v = VarFind(av[i], VAR_GLOBAL, 0);
	    if (!v)
		continue;
	    if (!unexport_env &&
		(v->flags & (VAR_EXPORTED|VAR_REEXPORT)) == VAR_EXPORTED) {
		unsetenv(v->name);
	    }
	    v->flags &= ~(VAR_EXPORTED|VAR_REEXPORT);
	    /*
	     * If we are unexporting a list,
	     * remove each one from .MAKE.EXPORTED.
	     * If we are removing them all,
	     * just delete .MAKE.EXPORTED below.
	     */
	    if (vlist == str) {
		n = snprintf(tmp, sizeof(tmp),
			     "${" MAKE_EXPORTED ":N%s}", v->name);
		if (n < (int)sizeof(tmp)) {
		    cp = Var_Subst(NULL, tmp, VAR_GLOBAL, 0);
		    Var_Set(MAKE_EXPORTED, cp, VAR_GLOBAL, 0);
		    free(cp);
		}
	    }
	}
	free(as);
	free(av);
	if (vlist != str) {
	    Var_Delete(MAKE_EXPORTED, VAR_GLOBAL);
	    free(vlist);
	}
    }
}

/*-
 *-----------------------------------------------------------------------
 * Var_Set --
 *	Set the variable name to the value val in the given context.
 *
 * Input:
 *	name		name of variable to set
 *	val		value to give to the variable
 *	ctxt		context in which to set it
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	If the variable doesn't yet exist, a new record is created for it.
 *	Else the old value is freed and the new one stuck in its place
 *
 * Notes:
 *	The variable is searched for only in its context before being
 *	created in that context. I.e. if the context is VAR_GLOBAL,
 *	only VAR_GLOBAL->context is searched. Likewise if it is VAR_CMD, only
 *	VAR_CMD->context is searched. This is done to avoid the literally
 *	thousands of unnecessary strcmp's that used to be done to
 *	set, say, $(@) or $(<).
 *	If the context is VAR_GLOBAL though, we check if the variable
 *	was set in VAR_CMD from the command line and skip it if so.
 *-----------------------------------------------------------------------
 */
void
Var_Set(const char *name, const char *val, GNode *ctxt, int flags)
{
    Var   *v;
    char *expanded_name = NULL;

    /*
     * We only look for a variable in the given context since anything set
     * here will override anything in a lower context, so there's not much
     * point in searching them all just to save a bit of memory...
     */
    if (strchr(name, '$') != NULL) {
	expanded_name = Var_Subst(NULL, name, ctxt, 0);
	if (expanded_name[0] == 0) {
	    if (DEBUG(VAR)) {
		fprintf(debug_file, "Var_Set(\"%s\", \"%s\", ...) "
			"name expands to empty string - ignored\n",
			name, val);
	    }
	    free(expanded_name);
	    return;
	}
	name = expanded_name;
    }
    if (ctxt == VAR_GLOBAL) {
	v = VarFind(name, VAR_CMD, 0);
	if (v != NULL) {
	    if ((v->flags & VAR_FROM_CMD)) {
		if (DEBUG(VAR)) {
		    fprintf(debug_file, "%s:%s = %s ignored!\n", ctxt->name, name, val);
		}
		goto out;
	    }
	    VarFreeEnv(v, TRUE);
	}
    }
    v = VarFind(name, ctxt, 0);
    if (v == NULL) {
	VarAdd(name, val, ctxt);
    } else {
	Buf_Empty(&v->val);
	Buf_AddBytes(&v->val, strlen(val), val);

	if (DEBUG(VAR)) {
	    fprintf(debug_file, "%s:%s = %s\n", ctxt->name, name, val);
	}
	if ((v->flags & VAR_EXPORTED)) {
	    Var_Export1(name, VAR_EXPORT_PARENT);
	}
    }
    /*
     * Any variables given on the command line are automatically exported
     * to the environment (as per POSIX standard)
     */
    if (ctxt == VAR_CMD && (flags & VAR_NO_EXPORT) == 0) {
	if (v == NULL) {
	    /* we just added it */
	    v = VarFind(name, ctxt, 0);
	}
	if (v != NULL)
	    v->flags |= VAR_FROM_CMD;
	/*
	 * If requested, don't export these in the environment
	 * individually.  We still put them in MAKEOVERRIDES so
	 * that the command-line settings continue to override
	 * Makefile settings.
	 */
	if (varNoExportEnv != TRUE)
	    setenv(name, val, 1);

	Var_Append(MAKEOVERRIDES, name, VAR_GLOBAL);
    }
    /*
     * Another special case.
     * Several make's support this sort of mechanism for tracking
     * recursion - but each uses a different name.
     * We allow the makefiles to update .MAKE.LEVEL and ensure
     * children see a correctly incremented value.
     */
    if (ctxt == VAR_GLOBAL && strcmp(MAKE_LEVEL, name) == 0) {
	char tmp[64];
	int level;
	
	level = atoi(val);
	snprintf(tmp, sizeof(tmp), "%u", level + 1);
	setenv(MAKE_LEVEL, tmp, 1);
    }
	
	
 out:
    if (expanded_name != NULL)
	free(expanded_name);
    if (v != NULL)
	VarFreeEnv(v, TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * Var_Append --
 *	The variable of the given name has the given value appended to it in
 *	the given context.
 *
 * Input:
 *	name		name of variable to modify
 *	val		String to append to it
 *	ctxt		Context in which this should occur
 *
 * Results:
 *	None
 *
 * Side Effects:
 *	If the variable doesn't exist, it is created. Else the strings
 *	are concatenated (with a space in between).
 *
 * Notes:
 *	Only if the variable is being sought in the global context is the
 *	environment searched.
 *	XXX: Knows its calling circumstances in that if called with ctxt
 *	an actual target, it will only search that context since only
 *	a local variable could be being appended to. This is actually
 *	a big win and must be tolerated.
 *-----------------------------------------------------------------------
 */
void
Var_Append(const char *name, const char *val, GNode *ctxt)
{
    Var		   *v;
    Hash_Entry	   *h;
    char *expanded_name = NULL;

    if (strchr(name, '$') != NULL) {
	expanded_name = Var_Subst(NULL, name, ctxt, 0);
	if (expanded_name[0] == 0) {
	    if (DEBUG(VAR)) {
		fprintf(debug_file, "Var_Append(\"%s\", \"%s\", ...) "
			"name expands to empty string - ignored\n",
			name, val);
	    }
	    free(expanded_name);
	    return;
	}
	name = expanded_name;
    }

    v = VarFind(name, ctxt, (ctxt == VAR_GLOBAL) ? FIND_ENV : 0);

    if (v == NULL) {
	VarAdd(name, val, ctxt);
    } else {
	Buf_AddByte(&v->val, ' ');
	Buf_AddBytes(&v->val, strlen(val), val);

	if (DEBUG(VAR)) {
	    fprintf(debug_file, "%s:%s = %s\n", ctxt->name, name,
		   Buf_GetAll(&v->val, NULL));
	}

	if (v->flags & VAR_FROM_ENV) {
	    /*
	     * If the original variable came from the environment, we
	     * have to install it in the global context (we could place
	     * it in the environment, but then we should provide a way to
	     * export other variables...)
	     */
	    v->flags &= ~VAR_FROM_ENV;
	    h = Hash_CreateEntry(&ctxt->context, name, NULL);
	    Hash_SetValue(h, v);
	}
    }
    if (expanded_name != NULL)
	free(expanded_name);
}

/*-
 *-----------------------------------------------------------------------
 * Var_Exists --
 *	See if the given variable exists.
 *
 * Input:
 *	name		Variable to find
 *	ctxt		Context in which to start search
 *
 * Results:
 *	TRUE if it does, FALSE if it doesn't
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
Boolean
Var_Exists(const char *name, GNode *ctxt)
{
    Var		  *v;
    char          *cp;

    if ((cp = strchr(name, '$')) != NULL) {
	cp = Var_Subst(NULL, name, ctxt, FALSE);
    }
    v = VarFind(cp ? cp : name, ctxt, FIND_CMD|FIND_GLOBAL|FIND_ENV);
    if (cp != NULL) {
	free(cp);
    }
    if (v == NULL) {
	return(FALSE);
    } else {
	(void)VarFreeEnv(v, TRUE);
    }
    return(TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * Var_Value --
 *	Return the value of the named variable in the given context
 *
 * Input:
 *	name		name to find
 *	ctxt		context in which to search for it
 *
 * Results:
 *	The value if the variable exists, NULL if it doesn't
 *
 * Side Effects:
 *	None
 *-----------------------------------------------------------------------
 */
char *
Var_Value(const char *name, GNode *ctxt, char **frp)
{
    Var            *v;

    v = VarFind(name, ctxt, FIND_ENV | FIND_GLOBAL | FIND_CMD);
    *frp = NULL;
    if (v != NULL) {
	char *p = (Buf_GetAll(&v->val, NULL));
	if (VarFreeEnv(v, FALSE))
	    *frp = p;
	return p;
    } else {
	return NULL;
    }
}

/*-
 *-----------------------------------------------------------------------
 * VarHead --
 *	Remove the tail of the given word and place the result in the given
 *	buffer.
 *
 * Input:
 *	word		Word to trim
 *	addSpace	True if need to add a space to the buffer
 *			before sticking in the head
 *	buf		Buffer in which to store it
 *
 * Results:
 *	TRUE if characters were added to the buffer (a space needs to be
 *	added to the buffer before the next word).
 *
 * Side Effects:
 *	The trimmed word is added to the buffer.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarHead(GNode *ctx __unused, Var_Parse_State *vpstate,
	char *word, Boolean addSpace, Buffer *buf,
	void *dummy)
{
    char *slash;

    slash = strrchr(word, '/');
    if (slash != NULL) {
	if (addSpace && vpstate->varSpace) {
	    Buf_AddByte(buf, vpstate->varSpace);
	}
	*slash = '\0';
	Buf_AddBytes(buf, strlen(word), word);
	*slash = '/';
	return (TRUE);
    } else {
	/*
	 * If no directory part, give . (q.v. the POSIX standard)
	 */
	if (addSpace && vpstate->varSpace)
	    Buf_AddByte(buf, vpstate->varSpace);
	Buf_AddByte(buf, '.');
    }
    return(dummy ? TRUE : TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * VarTail --
 *	Remove the head of the given word and place the result in the given
 *	buffer.
 *
 * Input:
 *	word		Word to trim
 *	addSpace	True if need to add a space to the buffer
 *			before adding the tail
 *	buf		Buffer in which to store it
 *
 * Results:
 *	TRUE if characters were added to the buffer (a space needs to be
 *	added to the buffer before the next word).
 *
 * Side Effects:
 *	The trimmed word is added to the buffer.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarTail(GNode *ctx __unused, Var_Parse_State *vpstate,
	char *word, Boolean addSpace, Buffer *buf,
	void *dummy)
{
    char *slash;

    if (addSpace && vpstate->varSpace) {
	Buf_AddByte(buf, vpstate->varSpace);
    }

    slash = strrchr(word, '/');
    if (slash != NULL) {
	*slash++ = '\0';
	Buf_AddBytes(buf, strlen(slash), slash);
	slash[-1] = '/';
    } else {
	Buf_AddBytes(buf, strlen(word), word);
    }
    return (dummy ? TRUE : TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * VarSuffix --
 *	Place the suffix of the given word in the given buffer.
 *
 * Input:
 *	word		Word to trim
 *	addSpace	TRUE if need to add a space before placing the
 *			suffix in the buffer
 *	buf		Buffer in which to store it
 *
 * Results:
 *	TRUE if characters were added to the buffer (a space needs to be
 *	added to the buffer before the next word).
 *
 * Side Effects:
 *	The suffix from the word is placed in the buffer.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarSuffix(GNode *ctx __unused, Var_Parse_State *vpstate,
	  char *word, Boolean addSpace, Buffer *buf,
	  void *dummy)
{
    char *dot;

    dot = strrchr(word, '.');
    if (dot != NULL) {
	if (addSpace && vpstate->varSpace) {
	    Buf_AddByte(buf, vpstate->varSpace);
	}
	*dot++ = '\0';
	Buf_AddBytes(buf, strlen(dot), dot);
	dot[-1] = '.';
	addSpace = TRUE;
    }
    return (dummy ? addSpace : addSpace);
}

/*-
 *-----------------------------------------------------------------------
 * VarRoot --
 *	Remove the suffix of the given word and place the result in the
 *	buffer.
 *
 * Input:
 *	word		Word to trim
 *	addSpace	TRUE if need to add a space to the buffer
 *			before placing the root in it
 *	buf		Buffer in which to store it
 *
 * Results:
 *	TRUE if characters were added to the buffer (a space needs to be
 *	added to the buffer before the next word).
 *
 * Side Effects:
 *	The trimmed word is added to the buffer.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarRoot(GNode *ctx __unused, Var_Parse_State *vpstate,
	char *word, Boolean addSpace, Buffer *buf,
	void *dummy)
{
    char *dot;

    if (addSpace && vpstate->varSpace) {
	Buf_AddByte(buf, vpstate->varSpace);
    }

    dot = strrchr(word, '.');
    if (dot != NULL) {
	*dot = '\0';
	Buf_AddBytes(buf, strlen(word), word);
	*dot = '.';
    } else {
	Buf_AddBytes(buf, strlen(word), word);
    }
    return (dummy ? TRUE : TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * VarMatch --
 *	Place the word in the buffer if it matches the given pattern.
 *	Callback function for VarModify to implement the :M modifier.
 *
 * Input:
 *	word		Word to examine
 *	addSpace	TRUE if need to add a space to the buffer
 *			before adding the word, if it matches
 *	buf		Buffer in which to store it
 *	pattern		Pattern the word must match
 *
 * Results:
 *	TRUE if a space should be placed in the buffer before the next
 *	word.
 *
 * Side Effects:
 *	The word may be copied to the buffer.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarMatch(GNode *ctx __unused, Var_Parse_State *vpstate,
	 char *word, Boolean addSpace, Buffer *buf,
	 void *pattern)
{
    if (DEBUG(VAR))
	fprintf(debug_file, "VarMatch [%s] [%s]\n", word, (char *)pattern);
    if (Str_Match(word, (char *)pattern)) {
	if (addSpace && vpstate->varSpace) {
	    Buf_AddByte(buf, vpstate->varSpace);
	}
	addSpace = TRUE;
	Buf_AddBytes(buf, strlen(word), word);
    }
    return(addSpace);
}

#ifdef SYSVVARSUB
/*-
 *-----------------------------------------------------------------------
 * VarSYSVMatch --
 *	Place the word in the buffer if it matches the given pattern.
 *	Callback function for VarModify to implement the System V %
 *	modifiers.
 *
 * Input:
 *	word		Word to examine
 *	addSpace	TRUE if need to add a space to the buffer
 *			before adding the word, if it matches
 *	buf		Buffer in which to store it
 *	patp		Pattern the word must match
 *
 * Results:
 *	TRUE if a space should be placed in the buffer before the next
 *	word.
 *
 * Side Effects:
 *	The word may be copied to the buffer.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarSYSVMatch(GNode *ctx, Var_Parse_State *vpstate,
	     char *word, Boolean addSpace, Buffer *buf,
	     void *patp)
{
    int len;
    char *ptr;
    VarPattern 	  *pat = (VarPattern *)patp;
    char *varexp;

    if (addSpace && vpstate->varSpace)
	Buf_AddByte(buf, vpstate->varSpace);

    addSpace = TRUE;

    if ((ptr = Str_SYSVMatch(word, pat->lhs, &len)) != NULL) {
        varexp = Var_Subst(NULL, pat->rhs, ctx, 0);
	Str_SYSVSubst(buf, varexp, ptr, len);
	free(varexp);
    } else {
	Buf_AddBytes(buf, strlen(word), word);
    }

    return(addSpace);
}
#endif


/*-
 *-----------------------------------------------------------------------
 * VarNoMatch --
 *	Place the word in the buffer if it doesn't match the given pattern.
 *	Callback function for VarModify to implement the :N modifier.
 *
 * Input:
 *	word		Word to examine
 *	addSpace	TRUE if need to add a space to the buffer
 *			before adding the word, if it matches
 *	buf		Buffer in which to store it
 *	pattern		Pattern the word must match
 *
 * Results:
 *	TRUE if a space should be placed in the buffer before the next
 *	word.
 *
 * Side Effects:
 *	The word may be copied to the buffer.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarNoMatch(GNode *ctx __unused, Var_Parse_State *vpstate,
	   char *word, Boolean addSpace, Buffer *buf,
	   void *pattern)
{
    if (!Str_Match(word, (char *)pattern)) {
	if (addSpace && vpstate->varSpace) {
	    Buf_AddByte(buf, vpstate->varSpace);
	}
	addSpace = TRUE;
	Buf_AddBytes(buf, strlen(word), word);
    }
    return(addSpace);
}


/*-
 *-----------------------------------------------------------------------
 * VarSubstitute --
 *	Perform a string-substitution on the given word, placing the
 *	result in the passed buffer.
 *
 * Input:
 *	word		Word to modify
 *	addSpace	True if space should be added before
 *			other characters
 *	buf		Buffer for result
 *	patternp	Pattern for substitution
 *
 * Results:
 *	TRUE if a space is needed before more characters are added.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarSubstitute(GNode *ctx __unused, Var_Parse_State *vpstate,
	      char *word, Boolean addSpace, Buffer *buf,
	      void *patternp)
{
    int  	wordLen;    /* Length of word */
    char 	*cp;	    /* General pointer */
    VarPattern	*pattern = (VarPattern *)patternp;

    wordLen = strlen(word);
    if ((pattern->flags & (VAR_SUB_ONE|VAR_SUB_MATCHED)) !=
	(VAR_SUB_ONE|VAR_SUB_MATCHED)) {
	/*
	 * Still substituting -- break it down into simple anchored cases
	 * and if none of them fits, perform the general substitution case.
	 */
	if ((pattern->flags & VAR_MATCH_START) &&
	    (strncmp(word, pattern->lhs, pattern->leftLen) == 0)) {
		/*
		 * Anchored at start and beginning of word matches pattern
		 */
		if ((pattern->flags & VAR_MATCH_END) &&
		    (wordLen == pattern->leftLen)) {
			/*
			 * Also anchored at end and matches to the end (word
			 * is same length as pattern) add space and rhs only
			 * if rhs is non-null.
			 */
			if (pattern->rightLen != 0) {
			    if (addSpace && vpstate->varSpace) {
				Buf_AddByte(buf, vpstate->varSpace);
			    }
			    addSpace = TRUE;
			    Buf_AddBytes(buf, pattern->rightLen, pattern->rhs);
			}
			pattern->flags |= VAR_SUB_MATCHED;
		} else if (pattern->flags & VAR_MATCH_END) {
		    /*
		     * Doesn't match to end -- copy word wholesale
		     */
		    goto nosub;
		} else {
		    /*
		     * Matches at start but need to copy in trailing characters
		     */
		    if ((pattern->rightLen + wordLen - pattern->leftLen) != 0){
			if (addSpace && vpstate->varSpace) {
			    Buf_AddByte(buf, vpstate->varSpace);
			}
			addSpace = TRUE;
		    }
		    Buf_AddBytes(buf, pattern->rightLen, pattern->rhs);
		    Buf_AddBytes(buf, wordLen - pattern->leftLen,
				 (word + pattern->leftLen));
		    pattern->flags |= VAR_SUB_MATCHED;
		}
	} else if (pattern->flags & VAR_MATCH_START) {
	    /*
	     * Had to match at start of word and didn't -- copy whole word.
	     */
	    goto nosub;
	} else if (pattern->flags & VAR_MATCH_END) {
	    /*
	     * Anchored at end, Find only place match could occur (leftLen
	     * characters from the end of the word) and see if it does. Note
	     * that because the $ will be left at the end of the lhs, we have
	     * to use strncmp.
	     */
	    cp = word + (wordLen - pattern->leftLen);
	    if ((cp >= word) &&
		(strncmp(cp, pattern->lhs, pattern->leftLen) == 0)) {
		/*
		 * Match found. If we will place characters in the buffer,
		 * add a space before hand as indicated by addSpace, then
		 * stuff in the initial, unmatched part of the word followed
		 * by the right-hand-side.
		 */
		if (((cp - word) + pattern->rightLen) != 0) {
		    if (addSpace && vpstate->varSpace) {
			Buf_AddByte(buf, vpstate->varSpace);
		    }
		    addSpace = TRUE;
		}
		Buf_AddBytes(buf, cp - word, word);
		Buf_AddBytes(buf, pattern->rightLen, pattern->rhs);
		pattern->flags |= VAR_SUB_MATCHED;
	    } else {
		/*
		 * Had to match at end and didn't. Copy entire word.
		 */
		goto nosub;
	    }
	} else {
	    /*
	     * Pattern is unanchored: search for the pattern in the word using
	     * String_FindSubstring, copying unmatched portions and the
	     * right-hand-side for each match found, handling non-global
	     * substitutions correctly, etc. When the loop is done, any
	     * remaining part of the word (word and wordLen are adjusted
	     * accordingly through the loop) is copied straight into the
	     * buffer.
	     * addSpace is set FALSE as soon as a space is added to the
	     * buffer.
	     */
	    Boolean done;
	    int origSize;

	    done = FALSE;
	    origSize = Buf_Size(buf);
	    while (!done) {
		cp = Str_FindSubstring(word, pattern->lhs);
		if (cp != NULL) {
		    if (addSpace && (((cp - word) + pattern->rightLen) != 0)){
			Buf_AddByte(buf, vpstate->varSpace);
			addSpace = FALSE;
		    }
		    Buf_AddBytes(buf, cp-word, word);
		    Buf_AddBytes(buf, pattern->rightLen, pattern->rhs);
		    wordLen -= (cp - word) + pattern->leftLen;
		    word = cp + pattern->leftLen;
		    if (wordLen == 0) {
			done = TRUE;
		    }
		    if ((pattern->flags & VAR_SUB_GLOBAL) == 0) {
			done = TRUE;
		    }
		    pattern->flags |= VAR_SUB_MATCHED;
		} else {
		    done = TRUE;
		}
	    }
	    if (wordLen != 0) {
		if (addSpace && vpstate->varSpace) {
		    Buf_AddByte(buf, vpstate->varSpace);
		}
		Buf_AddBytes(buf, wordLen, word);
	    }
	    /*
	     * If added characters to the buffer, need to add a space
	     * before we add any more. If we didn't add any, just return
	     * the previous value of addSpace.
	     */
	    return ((Buf_Size(buf) != origSize) || addSpace);
	}
	return (addSpace);
    }
 nosub:
    if (addSpace && vpstate->varSpace) {
	Buf_AddByte(buf, vpstate->varSpace);
    }
    Buf_AddBytes(buf, wordLen, word);
    return(TRUE);
}

#ifndef NO_REGEX
/*-
 *-----------------------------------------------------------------------
 * VarREError --
 *	Print the error caused by a regcomp or regexec call.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	An error gets printed.
 *
 *-----------------------------------------------------------------------
 */
static void
VarREError(int errnum, regex_t *pat, const char *str)
{
    char *errbuf;
    int errlen;

    errlen = regerror(errnum, pat, 0, 0);
    errbuf = bmake_malloc(errlen);
    regerror(errnum, pat, errbuf, errlen);
    Error("%s: %s", str, errbuf);
    free(errbuf);
}


/*-
 *-----------------------------------------------------------------------
 * VarRESubstitute --
 *	Perform a regex substitution on the given word, placing the
 *	result in the passed buffer.
 *
 * Results:
 *	TRUE if a space is needed before more characters are added.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarRESubstitute(GNode *ctx __unused, Var_Parse_State *vpstate __unused,
		char *word, Boolean addSpace, Buffer *buf,
		void *patternp)
{
    VarREPattern *pat;
    int xrv;
    char *wp;
    char *rp;
    int added;
    int flags = 0;

#define MAYBE_ADD_SPACE()		\
	if (addSpace && !added)		\
	    Buf_AddByte(buf, ' ');	\
	added = 1

    added = 0;
    wp = word;
    pat = patternp;

    if ((pat->flags & (VAR_SUB_ONE|VAR_SUB_MATCHED)) ==
	(VAR_SUB_ONE|VAR_SUB_MATCHED))
	xrv = REG_NOMATCH;
    else {
    tryagain:
	xrv = regexec(&pat->re, wp, pat->nsub, pat->matches, flags);
    }

    switch (xrv) {
    case 0:
	pat->flags |= VAR_SUB_MATCHED;
	if (pat->matches[0].rm_so > 0) {
	    MAYBE_ADD_SPACE();
	    Buf_AddBytes(buf, pat->matches[0].rm_so, wp);
	}

	for (rp = pat->replace; *rp; rp++) {
	    if ((*rp == '\\') && ((rp[1] == '&') || (rp[1] == '\\'))) {
		MAYBE_ADD_SPACE();
		Buf_AddByte(buf,rp[1]);
		rp++;
	    }
	    else if ((*rp == '&') ||
		((*rp == '\\') && isdigit((unsigned char)rp[1]))) {
		int n;
		const char *subbuf;
		int sublen;
		char errstr[3];

		if (*rp == '&') {
		    n = 0;
		    errstr[0] = '&';
		    errstr[1] = '\0';
		} else {
		    n = rp[1] - '0';
		    errstr[0] = '\\';
		    errstr[1] = rp[1];
		    errstr[2] = '\0';
		    rp++;
		}

		if (n > pat->nsub) {
		    Error("No subexpression %s", &errstr[0]);
		    subbuf = "";
		    sublen = 0;
		} else if ((pat->matches[n].rm_so == -1) &&
			   (pat->matches[n].rm_eo == -1)) {
		    Error("No match for subexpression %s", &errstr[0]);
		    subbuf = "";
		    sublen = 0;
	        } else {
		    subbuf = wp + pat->matches[n].rm_so;
		    sublen = pat->matches[n].rm_eo - pat->matches[n].rm_so;
		}

		if (sublen > 0) {
		    MAYBE_ADD_SPACE();
		    Buf_AddBytes(buf, sublen, subbuf);
		}
	    } else {
		MAYBE_ADD_SPACE();
		Buf_AddByte(buf, *rp);
	    }
	}
	wp += pat->matches[0].rm_eo;
	if (pat->flags & VAR_SUB_GLOBAL) {
	    flags |= REG_NOTBOL;
	    if (pat->matches[0].rm_so == 0 && pat->matches[0].rm_eo == 0) {
		MAYBE_ADD_SPACE();
		Buf_AddByte(buf, *wp);
		wp++;

	    }
	    if (*wp)
		goto tryagain;
	}
	if (*wp) {
	    MAYBE_ADD_SPACE();
	    Buf_AddBytes(buf, strlen(wp), wp);
	}
	break;
    default:
	VarREError(xrv, &pat->re, "Unexpected regex error");
       /* fall through */
    case REG_NOMATCH:
	if (*wp) {
	    MAYBE_ADD_SPACE();
	    Buf_AddBytes(buf,strlen(wp),wp);
	}
	break;
    }
    return(addSpace||added);
}
#endif



/*-
 *-----------------------------------------------------------------------
 * VarLoopExpand --
 *	Implements the :@<temp>@<string>@ modifier of ODE make.
 *	We set the temp variable named in pattern.lhs to word and expand
 *	pattern.rhs storing the result in the passed buffer.
 *
 * Input:
 *	word		Word to modify
 *	addSpace	True if space should be added before
 *			other characters
 *	buf		Buffer for result
 *	pattern		Datafor substitution
 *
 * Results:
 *	TRUE if a space is needed before more characters are added.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
VarLoopExpand(GNode *ctx __unused, Var_Parse_State *vpstate __unused,
	      char *word, Boolean addSpace, Buffer *buf,
	      void *loopp)
{
    VarLoop_t	*loop = (VarLoop_t *)loopp;
    char *s;
    int slen;

    if (word && *word) {
        Var_Set(loop->tvar, word, loop->ctxt, VAR_NO_EXPORT);
        s = Var_Subst(NULL, loop->str, loop->ctxt, loop->errnum);
        if (s != NULL && *s != '\0') {
            if (addSpace && *s != '\n')
                Buf_AddByte(buf, ' ');
            Buf_AddBytes(buf, (slen = strlen(s)), s);
            addSpace = (slen > 0 && s[slen - 1] != '\n');
            free(s);
        }
    }
    return addSpace;
}


/*-
 *-----------------------------------------------------------------------
 * VarSelectWords --
 *	Implements the :[start..end] modifier.
 *	This is a special case of VarModify since we want to be able
 *	to scan the list backwards if start > end.
 *
 * Input:
 *	str		String whose words should be trimmed
 *	seldata		words to select
 *
 * Results:
 *	A string of all the words selected.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static char *
VarSelectWords(GNode *ctx __unused, Var_Parse_State *vpstate,
	       const char *str, VarSelectWords_t *seldata)
{
    Buffer  	  buf;		    /* Buffer for the new string */
    Boolean 	  addSpace; 	    /* TRUE if need to add a space to the
				     * buffer before adding the trimmed
				     * word */
    char **av;			    /* word list */
    char *as;			    /* word list memory */
    int ac, i;
    int start, end, step;

    Buf_Init(&buf, 0);
    addSpace = FALSE;

    if (vpstate->oneBigWord) {
	/* fake what brk_string() would do if there were only one word */
	ac = 1;
    	av = bmake_malloc((ac + 1) * sizeof(char *));
	as = bmake_strdup(str);
	av[0] = as;
	av[1] = NULL;
    } else {
	av = brk_string(str, &ac, FALSE, &as);
    }

    /*
     * Now sanitize sel…