No empty .Rs/.Re

[netbsd-mini2440.git] / usr.bin / make / var.c

/*      $NetBSD: var.c,v 1.154 2009/09/08 17:29:20 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 1.154 2009/09/08 17:29:20 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 1.154 2009/09/08 17:29:20 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.
 */

#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, '$')) {
        if (parent) {
            /*
             * Flag this as something we need to re-export.
             * No point actually exporting it now though,
             * the child can do it at the last minute.
             */
            v->flags |= (VAR_EXPORTED|VAR_REEXPORT);
            return 1;
        }
        n = snprintf(tmp, sizeof(tmp), "${%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 ac;
    int i;

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

    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, VAR_EXPORT_PARENT)) {
            if (VAR_EXPORTED_ALL != var_exportedVars)
                var_exportedVars = VAR_EXPORTED_YES;
            if (isExport) {
                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 seldata.
     * If seldata->start or seldata->end are negative, convert them to
     * the positive equivalents (-1 gets converted to argc, -2 gets
     * converted to (argc-1), etc.).
     */
    if (seldata->start < 0)
        seldata->start = ac + seldata->start + 1;
    if (seldata->end < 0)
        seldata->end = ac + seldata->end + 1;

    /*
     * We avoid scanning more of the list than we need to.
     */
    if (seldata->start > seldata->end) {
        start = MIN(ac, seldata->start) - 1;
        end = MAX(0, seldata->end - 1);
        step = -1;
    } else {
        start = MAX(0, seldata->start - 1);
        end = MIN(ac, seldata->end);
        step = 1;
    }

    for (i = start;
         (step < 0 && i >= end) || (step > 0 && i < end);
         i += step) {
        if (av[i] && *av[i]) {
            if (addSpace && vpstate->varSpace) {
                Buf_AddByte(&buf, vpstate->varSpace);
            }
            Buf_AddBytes(&buf, strlen(av[i]), av[i]);
            addSpace = TRUE;
        }
    }

    free(as);
    free(av);

    return Buf_Destroy(&buf, FALSE);
}

/*-
 *-----------------------------------------------------------------------
 * VarModify --
 *      Modify each of the words of the passed string using the given
 *      function. Used to implement all modifiers.
 *
 * Input:
 *      str             String whose words should be trimmed
 *      modProc         Function to use to modify them
 *      datum           Datum to pass it
 *
 * Results:
 *      A string of all the words modified appropriately.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
static char *
VarModify(GNode *ctx, Var_Parse_State *vpstate,
    const char *str,
    Boolean (*modProc)(GNode *, Var_Parse_State *, char *,
                       Boolean, Buffer *, void *),
    void *datum)
{
    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;

    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);
    }

    for (i = 0; i < ac; i++) {
        addSpace = (*modProc)(ctx, vpstate, av[i], addSpace, &buf, datum);
    }

    free(as);
    free(av);

    return Buf_Destroy(&buf, FALSE);
}


static int
VarWordCompare(const void *a, const void *b)
{
        int r = strcmp(*(const char * const *)a, *(const char * const *)b);
        return r;
}

/*-
 *-----------------------------------------------------------------------
 * VarOrder --
 *      Order the words in the string.
 *
 * Input:
 *      str             String whose words should be sorted.
 *      otype           How to order: s - sort, x - random.
 *
 * Results:
 *      A string containing the words ordered.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
static char *
VarOrder(const char *str, const char otype)
{
    Buffer        buf;              /* Buffer for the new string */
    char **av;                      /* word list [first word does not count] */
    char *as;                       /* word list memory */
    int ac, i;

    Buf_Init(&buf, 0);

    av = brk_string(str, &ac, FALSE, &as);

    if (ac > 0)
        switch (otype) {
        case 's':       /* sort alphabetically */
            qsort(av, ac, sizeof(char *), VarWordCompare);
            break;
        case 'x':       /* randomize */
        {
            int rndidx;
            char *t;

            /*
             * We will use [ac..2] range for mod factors. This will produce
             * random numbers in [(ac-1)..0] interval, and minimal
             * reasonable value for mod factor is 2 (the mod 1 will produce
             * 0 with probability 1).
             */
            for (i = ac-1; i > 0; i--) {
                rndidx = random() % (i + 1);
                if (i != rndidx) {
                    t = av[i];
                    av[i] = av[rndidx];
                    av[rndidx] = t;
                }
            }
        }
        } /* end of switch */

    for (i = 0; i < ac; i++) {
        Buf_AddBytes(&buf, strlen(av[i]), av[i]);
        if (i != ac - 1)
            Buf_AddByte(&buf, ' ');
    }

    free(as);
    free(av);

    return Buf_Destroy(&buf, FALSE);
}


/*-
 *-----------------------------------------------------------------------
 * VarUniq --
 *      Remove adjacent duplicate words.
 *
 * Input:
 *      str             String whose words should be sorted
 *
 * Results:
 *      A string containing the resulting words.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
static char *
VarUniq(const char *str)
{
    Buffer        buf;              /* Buffer for new string */
    char        **av;               /* List of words to affect */
    char         *as;               /* Word list memory */
    int           ac, i, j;

    Buf_Init(&buf, 0);
    av = brk_string(str, &ac, FALSE, &as);

    if (ac > 1) {
        for (j = 0, i = 1; i < ac; i++)
            if (strcmp(av[i], av[j]) != 0 && (++j != i))
                av[j] = av[i];
        ac = j + 1;
    }

    for (i = 0; i < ac; i++) {
        Buf_AddBytes(&buf, strlen(av[i]), av[i]);
        if (i != ac - 1)
            Buf_AddByte(&buf, ' ');
    }

    free(as);
    free(av);

    return Buf_Destroy(&buf, FALSE);
}


/*-
 *-----------------------------------------------------------------------
 * VarGetPattern --
 *      Pass through the tstr looking for 1) escaped delimiters,
 *      '$'s and backslashes (place the escaped character in
 *      uninterpreted) and 2) unescaped $'s that aren't before
 *      the delimiter (expand the variable substitution unless flags
 *      has VAR_NOSUBST set).
 *      Return the expanded string or NULL if the delimiter was missing
 *      If pattern is specified, handle escaped ampersands, and replace
 *      unescaped ampersands with the lhs of the pattern.
 *
 * Results:
 *      A string of all the words modified appropriately.
 *      If length is specified, return the string length of the buffer
 *      If flags is specified and the last character of the pattern is a
 *      $ set the VAR_MATCH_END bit of flags.
 *
 * Side Effects:
 *      None.
 *-----------------------------------------------------------------------
 */
static char *
VarGetPattern(GNode *ctxt, Var_Parse_State *vpstate __unused,
              int errnum, const char **tstr, int delim, int *flags,
              int *length, VarPattern *pattern)
{
    const char *cp;
    char *rstr;
    Buffer buf;
    int junk;

    Buf_Init(&buf, 0);
    if (length == NULL)
        length = &junk;

#define IS_A_MATCH(cp, delim) \
    ((cp[0] == '\\') && ((cp[1] == delim) ||  \
     (cp[1] == '\\') || (cp[1] == '$') || (pattern && (cp[1] == '&'))))

    /*
     * Skim through until the matching delimiter is found;
     * pick up variable substitutions on the way. Also allow
     * backslashes to quote the delimiter, $, and \, but don't
     * touch other backslashes.
     */
    for (cp = *tstr; *cp && (*cp != delim); cp++) {
        if (IS_A_MATCH(cp, delim)) {
            Buf_AddByte(&buf, cp[1]);
            cp++;
        } else if (*cp == '$') {
            if (cp[1] == delim) {
                if (flags == NULL)
                    Buf_AddByte(&buf, *cp);
                else
                    /*
                     * Unescaped $ at end of pattern => anchor
                     * pattern at end.
                     */
                    *flags |= VAR_MATCH_END;
            } else {
                if (flags == NULL || (*flags & VAR_NOSUBST) == 0) {
                    char   *cp2;
                    int     len;
                    void   *freeIt;

                    /*
                     * If unescaped dollar sign not before the
                     * delimiter, assume it's a variable
                     * substitution and recurse.
                     */
                    cp2 = Var_Parse(cp, ctxt, errnum, &len, &freeIt);
                    Buf_AddBytes(&buf, strlen(cp2), cp2);
                    if (freeIt)
                        free(freeIt);
                    cp += len - 1;
                } else {
                    const char *cp2 = &cp[1];

                    if (*cp2 == PROPEN || *cp2 == BROPEN) {
                        /*
                         * Find the end of this variable reference
                         * and suck it in without further ado.
                         * It will be interperated later.
                         */
                        int have = *cp2;
                        int want = (*cp2 == PROPEN) ? PRCLOSE : BRCLOSE;
                        int depth = 1;

                        for (++cp2; *cp2 != '\0' && depth > 0; ++cp2) {
                            if (cp2[-1] != '\\') {
                                if (*cp2 == have)
                                    ++depth;
                                if (*cp2 == want)
                                    --depth;
                            }
                        }
                        Buf_AddBytes(&buf, cp2 - cp, cp);
                        cp = --cp2;
                    } else
                        Buf_AddByte(&buf, *cp);
                }
            }
        }
        else if (pattern && *cp == '&')
            Buf_AddBytes(&buf, pattern->leftLen, pattern->lhs);
        else
            Buf_AddByte(&buf, *cp);
    }

    if (*cp != delim) {
        *tstr = cp;
        *length = 0;
        return NULL;
    }

    *tstr = ++cp;
    *length = Buf_Size(&buf);
    rstr = Buf_Destroy(&buf, FALSE);
    if (DEBUG(VAR))
        fprintf(debug_file, "Modifier pattern: \"%s\"\n", rstr);
    return rstr;
}

/*-
 *-----------------------------------------------------------------------
 * VarQuote --
 *      Quote shell meta-characters in the string
 *
 * Results:
 *      The quoted string
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
static char *
VarQuote(char *str)
{

    Buffer        buf;
    /* This should cover most shells :-( */
    static const char meta[] = "\n \t'`\";&<>()|*?{}[]\\$!#^~";
    const char  *newline;
    size_t len, nlen;

    if ((newline = Shell_GetNewline()) == NULL)
            newline = "\\\n";
    nlen = strlen(newline);

    Buf_Init(&buf, 0);
    while (*str != '\0') {
        if ((len = strcspn(str, meta)) != 0) {
            Buf_AddBytes(&buf, len, str);
            str += len;
        } else if (*str == '\n') {
            Buf_AddBytes(&buf, nlen, newline);
            ++str;
        } else {
            Buf_AddByte(&buf, '\\');
            Buf_AddByte(&buf, *str);
            ++str;
        }
    }
    str = Buf_Destroy(&buf, FALSE);
    if (DEBUG(VAR))
        fprintf(debug_file, "QuoteMeta: [%s]\n", str);
    return str;
}

/*-
 *-----------------------------------------------------------------------
 * VarChangeCase --
 *      Change the string to all uppercase or all lowercase
 *
 * Input:
 *      str             String to modify
 *      upper           TRUE -> uppercase, else lowercase
 *
 * Results:
 *      The string with case changed
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
static char *
VarChangeCase(char *str, int upper)
{
   Buffer         buf;
   int            (*modProc)(int);

   modProc = (upper ? toupper : tolower);
   Buf_Init(&buf, 0);
   for (; *str ; str++) {
       Buf_AddByte(&buf, modProc(*str));
   }
   return Buf_Destroy(&buf, FALSE);
}

/*
 * Now we need to apply any modifiers the user wants applied.
 * These are:
 *        :M<pattern>   words which match the given <pattern>.
 *                      <pattern> is of the standard file
 *                      wildcarding form.
 *        :N<pattern>   words which do not match the given <pattern>.
 *        :S<d><pat1><d><pat2><d>[1gW]
 *                      Substitute <pat2> for <pat1> in the value
 *        :C<d><pat1><d><pat2><d>[1gW]
 *                      Substitute <pat2> for regex <pat1> in the value
 *        :H            Substitute the head of each word
 *        :T            Substitute the tail of each word
 *        :E            Substitute the extension (minus '.') of
 *                      each word
 *        :R            Substitute the root of each word
 *                      (pathname minus the suffix).
 *        :O            ("Order") Alphabeticaly sort words in variable.
 *        :Ox           ("intermiX") Randomize words in variable.
 *        :u            ("uniq") Remove adjacent duplicate words.
 *        :tu           Converts the variable contents to uppercase.
 *        :tl           Converts the variable contents to lowercase.
 *        :ts[c]        Sets varSpace - the char used to
 *                      separate words to 'c'. If 'c' is
 *                      omitted then no separation is used.
 *        :tW           Treat the variable contents as a single
 *                      word, even if it contains spaces.
 *                      (Mnemonic: one big 'W'ord.)
 *        :tw           Treat the variable contents as multiple
 *                      space-separated words.
 *                      (Mnemonic: many small 'w'ords.)
 *        :[index]      Select a single word from the value.
 *        :[start..end] Select multiple words from the value.
 *        :[*] or :[0]  Select the entire value, as a single
 *                      word.  Equivalent to :tW.
 *        :[@]          Select the entire value, as multiple
 *                      words.  Undoes the effect of :[*].
 *                      Equivalent to :tw.
 *        :[#]          Returns the number of words in the value.
 *
 *        :?<true-value>:<false-value>
 *                      If the variable evaluates to true, return
 *                      true value, else return the second value.
 *        :lhs=rhs      Like :S, but the rhs goes to the end of
 *                      the invocation.
 *        :sh           Treat the current value as a command
 *                      to be run, new value is its output.
 * The following added so we can handle ODE makefiles.
 *        :@<tmpvar>@<newval>@
 *                      Assign a temporary local variable <tmpvar>
 *                      to the current value of each word in turn
 *                      and replace each word with the result of
 *                      evaluating <newval>
 *        :D<newval>    Use <newval> as value if variable defined
 *        :U<newval>    Use <newval> as value if variable undefined
 *        :L            Use the name of the variable as the value.
 *        :P            Use the path of the node that has the same
 *                      name as the variable as the value.  This
 *                      basically includes an implied :L so that
 *                      the common method of refering to the path
 *                      of your dependent 'x' in a rule is to use
 *                      the form '${x:P}'.
 *        :!<cmd>!      Run cmd much the same as :sh run's the
 *                      current value of the variable.
 * The ::= modifiers, actually assign a value to the variable.
 * Their main purpose is in supporting modifiers of .for loop
 * iterators and other obscure uses.  They always expand to
 * nothing.  In a target rule that would otherwise expand to an
 * empty line they can be preceded with @: to keep make happy.
 * Eg.
 *
 * foo: .USE
 * .for i in ${.TARGET} ${.TARGET:R}.gz
 *      @: ${t::=$i}
 *      @echo blah ${t:T}
 * .endfor
 *
 *        ::=<str>      Assigns <str> as the new value of variable.
 *        ::?=<str>     Assigns <str> as value of variable if
 *                      it was not already set.
 *        ::+=<str>     Appends <str> to variable.
 *        ::!=<cmd>     Assigns output of <cmd> as the new value of
 *                      variable.
 */

static char *
ApplyModifiers(char *nstr, const char *tstr,
               int startc, int endc,
               Var *v, GNode *ctxt, Boolean errnum,
               int *lengthPtr, void **freePtr)
{
    const char     *start;
    const char     *cp;         /* Secondary pointer into str (place marker
                                 * for tstr) */
    char           *newStr;     /* New value to return */
    char            termc;      /* Character which terminated scan */
    int             cnt;        /* Used to count brace pairs when variable in
                                 * in parens or braces */
    char        delim;
    int         modifier;       /* that we are processing */
    Var_Parse_State parsestate; /* Flags passed to helper functions */

    delim = '\0';
    parsestate.oneBigWord = FALSE;
    parsestate.varSpace = ' ';  /* word separator */

    start = cp = tstr;

    while (*tstr && *tstr != endc) {

        if (*tstr == '$') {
            /*
             * We have some complex modifiers in a variable.
             */
            void *freeIt;
            char *rval;
            int rlen;

            rval = Var_Parse(tstr, ctxt, errnum, &rlen, &freeIt);

            if (DEBUG(VAR)) {
                fprintf(debug_file, "Got '%s' from '%.*s'%.*s\n",
                       rval, rlen, tstr, rlen, tstr + rlen);
            }

            tstr += rlen;

            if (rval != NULL && *rval) {
                int used;

                nstr = ApplyModifiers(nstr, rval,
                                      0, 0,
                                      v, ctxt, errnum, &used, freePtr);
                if (nstr == var_Error
                    || (nstr == varNoError && errnum == 0)
                    || strlen(rval) != (size_t) used) {
                    if (freeIt)
                        free(freeIt);
                    goto out;           /* error already reported */
                }
            }
            if (freeIt)
                free(freeIt);
            if (*tstr == ':')
                tstr++;
            else if (!*tstr && endc) {
                Error("Unclosed variable specification after complex modifier (expecting '%c') for %s", endc, v->name);
                goto out;
            }
            continue;
        }
        if (DEBUG(VAR)) {
            fprintf(debug_file, "Applying :%c to \"%s\"\n", *tstr, nstr);
        }
        newStr = var_Error;
        switch ((modifier = *tstr)) {
        case ':':
            {
                if (tstr[1] == '=' ||
                    (tstr[2] == '=' &&
                     (tstr[1] == '!' || tstr[1] == '+' || tstr[1] == '?'))) {
                    /*
                     * "::=", "::!=", "::+=", or "::?="
                     */
                    GNode *v_ctxt;              /* context where v belongs */
                    const char *emsg;
                    char *sv_name;
                    VarPattern  pattern;
                    int how;

                    if (v->name[0] == 0)
                        goto bad_modifier;

                    v_ctxt = ctxt;
                    sv_name = NULL;
                    ++tstr;
                    if (v->flags & VAR_JUNK) {
                        /*
                         * We need to bmake_strdup() it incase
                         * VarGetPattern() recurses.
                         */
                        sv_name = v->name;
                        v->name = bmake_strdup(v->name);
                    } else if (ctxt != VAR_GLOBAL) {
                        Var *gv = VarFind(v->name, ctxt, 0);
                        if (gv == NULL)
                            v_ctxt = VAR_GLOBAL;
                        else
                            VarFreeEnv(gv, TRUE);
                    }

                    switch ((how = *tstr)) {
                    case '+':
                    case '?':
                    case '!':
                        cp = &tstr[2];
                        break;
                    default:
                        cp = ++tstr;
                        break;
                    }
                    delim = BRCLOSE;
                    pattern.flags = 0;

                    pattern.rhs = VarGetPattern(ctxt, &parsestate, errnum,
                                                &cp, delim, NULL,
                                                &pattern.rightLen,
                                                NULL);
                    if (v->flags & VAR_JUNK) {
                        /* restore original name */
                        free(v->name);
                        v->name = sv_name;
                    }
                    if (pattern.rhs == NULL)
                        goto cleanup;

                    termc = *--cp;
                    delim = '\0';

                    switch (how) {
                    case '+':
                        Var_Append(v->name, pattern.rhs, v_ctxt);
                        break;
                    case '!':
                        newStr = Cmd_Exec(pattern.rhs, &emsg);
                        if (emsg)
                            Error(emsg, nstr);
                        else
                            Var_Set(v->name, newStr,  v_ctxt, 0);
                        if (newStr)
                            free(newStr);
                        break;
                    case '?':
                        if ((v->flags & VAR_JUNK) == 0)
                            break;
                        /* FALLTHROUGH */
                    default:
                        Var_Set(v->name, pattern.rhs, v_ctxt, 0);
                        break;
                    }
                    free(UNCONST(pattern.rhs));
                    newStr = var_Error;
                    break;
                }
                goto default_case; /* "::<unrecognised>" */
            }
        case '@':
            {
                VarLoop_t       loop;
                int flags = VAR_NOSUBST;

                cp = ++tstr;
                delim = '@';
                if ((loop.tvar = VarGetPattern(ctxt, &parsestate, errnum,
                                               &cp, delim,
                                               &flags, &loop.tvarLen,
                                               NULL)) == NULL)
                    goto cleanup;

                if ((loop.str = VarGetPattern(ctxt, &parsestate, errnum,
                                              &cp, delim,
                                              &flags, &loop.strLen,
                                              NULL)) == NULL)
                    goto cleanup;

                termc = *cp;
                delim = '\0';

                loop.errnum = errnum;
                loop.ctxt = ctxt;
                newStr = VarModify(ctxt, &parsestate, nstr, VarLoopExpand,
                                   &loop);
                free(loop.tvar);
                free(loop.str);
                break;
            }
        case 'D':
        case 'U':
            {
                Buffer  buf;            /* Buffer for patterns */
                int         wantit;     /* want data in buffer */

                /*
                 * Pass through tstr looking for 1) escaped delimiters,
                 * '$'s and backslashes (place the escaped character in
                 * uninterpreted) and 2) unescaped $'s that aren't before
                 * the delimiter (expand the variable substitution).
                 * The result is left in the Buffer buf.
                 */
                Buf_Init(&buf, 0);
                for (cp = tstr + 1;
                     *cp != endc && *cp != ':' && *cp != '\0';
                     cp++) {
                    if ((*cp == '\\') &&
                        ((cp[1] == ':') ||
                         (cp[1] == '$') ||
                         (cp[1] == endc) ||
                         (cp[1] == '\\')))
                        {
                            Buf_AddByte(&buf, cp[1]);
                            cp++;
                        } else if (*cp == '$') {
                            /*
                             * If unescaped dollar sign, assume it's a
                             * variable substitution and recurse.
                             */
                            char    *cp2;
                            int     len;
                            void    *freeIt;

                            cp2 = Var_Parse(cp, ctxt, errnum, &len, &freeIt);
                            Buf_AddBytes(&buf, strlen(cp2), cp2);
                            if (freeIt)
                                free(freeIt);
                            cp += len - 1;
                        } else {
                            Buf_AddByte(&buf, *cp);
                        }
                }

                termc = *cp;

                if (*tstr == 'U')
                    wantit = ((v->flags & VAR_JUNK) != 0);
                else
                    wantit = ((v->flags & VAR_JUNK) == 0);
                if ((v->flags & VAR_JUNK) != 0)
                    v->flags |= VAR_KEEP;
                if (wantit) {
                    newStr = Buf_Destroy(&buf, FALSE);
                } else {
                    newStr = nstr;
                    Buf_Destroy(&buf, TRUE);
                }
                break;
            }
        case 'L':
            {
                if ((v->flags & VAR_JUNK) != 0)
                    v->flags |= VAR_KEEP;
                newStr = bmake_strdup(v->name);
                cp = ++tstr;
                termc = *tstr;
                break;
            }
        case 'P':
            {
                GNode *gn;

                if ((v->flags & VAR_JUNK) != 0)
                    v->flags |= VAR_KEEP;
                gn = Targ_FindNode(v->name, TARG_NOCREATE);
                if (gn == NULL || gn->type & OP_NOPATH) {
                    newStr = NULL;
                } else if (gn->path) {
                    newStr = bmake_strdup(gn->path);
                } else {
                    newStr = Dir_FindFile(v->name, Suff_FindPath(gn));
                }
                if (!newStr) {
                    newStr = bmake_strdup(v->name);
                }
                cp = ++tstr;
                termc = *tstr;
                break;
            }
        case '!':
            {
                const char *emsg;
                VarPattern          pattern;
                pattern.flags = 0;

                delim = '!';

                cp = ++tstr;
                if ((pattern.rhs = VarGetPattern(ctxt, &parsestate, errnum,
                                                 &cp, delim,
                                                 NULL, &pattern.rightLen,
                                                 NULL)) == NULL)
                    goto cleanup;
                newStr = Cmd_Exec(pattern.rhs, &emsg);
                free(UNCONST(pattern.rhs));
                if (emsg)
                    Error(emsg, nstr);
                termc = *cp;
                delim = '\0';
                if (v->flags & VAR_JUNK) {
                    v->flags |= VAR_KEEP;
                }
                break;
            }
        case '[':
            {
                /*
                 * Look for the closing ']', recursively
                 * expanding any embedded variables.
                 *
                 * estr is a pointer to the expanded result,
                 * which we must free().
                 */
                char *estr;

                cp = tstr+1; /* point to char after '[' */
                delim = ']'; /* look for closing ']' */
                estr = VarGetPattern(ctxt, &parsestate,
                                     errnum, &cp, delim,
                                     NULL, NULL, NULL);
                if (estr == NULL)
                    goto cleanup; /* report missing ']' */
                /* now cp points just after the closing ']' */
                delim = '\0';
                if (cp[0] != ':' && cp[0] != endc) {
                    /* Found junk after ']' */
                    free(estr);
                    goto bad_modifier;
                }
                if (estr[0] == '\0') {
                    /* Found empty square brackets in ":[]". */
                    free(estr);
                    goto bad_modifier;
                } else if (estr[0] == '#' && estr[1] == '\0') {
                    /* Found ":[#]" */

                    /*
                     * We will need enough space for the decimal
                     * representation of an int.  We calculate the
                     * space needed for the octal representation,
                     * and add enough slop to cope with a '-' sign
                     * (which should never be needed) and a '\0'
                     * string terminator.
                     */
                    int newStrSize =
                        (sizeof(int) * CHAR_BIT + 2) / 3 + 2;

                    newStr = bmake_malloc(newStrSize);
                    if (parsestate.oneBigWord) {
                        strncpy(newStr, "1", newStrSize);
                    } else {
                        /* XXX: brk_string() is a rather expensive
                         * way of counting words. */
                        char **av;
                        char *as;
                        int ac;

                        av = brk_string(nstr, &ac, FALSE, &as);
                        snprintf(newStr, newStrSize,  "%d", ac);
                        free(as);
                        free(av);
                    }
                    termc = *cp;
                    free(estr);
                    break;
                } else if (estr[0] == '*' && estr[1] == '\0') {
                    /* Found ":[*]" */
                    parsestate.oneBigWord = TRUE;
                    newStr = nstr;
                    termc = *cp;
                    free(estr);
                    break;
                } else if (estr[0] == '@' && estr[1] == '\0') {
                    /* Found ":[@]" */
                    parsestate.oneBigWord = FALSE;
                    newStr = nstr;
                    termc = *cp;
                    free(estr);
                    break;
                } else {
                    /*
                     * We expect estr to contain a single
                     * integer for :[N], or two integers
                     * separated by ".." for :[start..end].
                     */
                    char *ep;

                    VarSelectWords_t seldata = { 0, 0 };

                    seldata.start = strtol(estr, &ep, 0);
                    if (ep == estr) {
                        /* Found junk instead of a number */
                        free(estr);
                        goto bad_modifier;
                    } else if (ep[0] == '\0') {
                        /* Found only one integer in :[N] */
                        seldata.end = seldata.start;
                    } else if (ep[0] == '.' && ep[1] == '.' &&
                               ep[2] != '\0') {
                        /* Expecting another integer after ".." */
                        ep += 2;
                        seldata.end = strtol(ep, &ep, 0);
                        if (ep[0] != '\0') {
                            /* Found junk after ".." */
                            free(estr);
                            goto bad_modifier;
                        }
                    } else {
                        /* Found junk instead of ".." */
                        free(estr);
                        goto bad_modifier;
                    }
                    /*
                     * Now seldata is properly filled in,
                     * but we still have to check for 0 as
                     * a special case.
                     */
                    if (seldata.start == 0 && seldata.end == 0) {
                        /* ":[0]" or perhaps ":[0..0]" */
                        parsestate.oneBigWord = TRUE;
                        newStr = nstr;
                        termc = *cp;
                        free(estr);
                        break;
                    } else if (seldata.start == 0 ||
                               seldata.end == 0) {
                        /* ":[0..N]" or ":[N..0]" */
                        free(estr);
                        goto bad_modifier;
                    }
                    /*
                     * Normal case: select the words
                     * described by seldata.
                     */
                    newStr = VarSelectWords(ctxt, &parsestate,
                                            nstr, &seldata);

                    termc = *cp;
                    free(estr);
                    break;
                }

            }
        case 't':
            {
                cp = tstr + 1;  /* make sure it is set */
                if (tstr[1] != endc && tstr[1] != ':') {
                    if (tstr[1] == 's') {
                        /*
                         * Use the char (if any) at tstr[2]
                         * as the word separator.
                         */
                        VarPattern pattern;

                        if (tstr[2] != endc &&
                            (tstr[3] == endc || tstr[3] == ':')) {
                            /* ":ts<unrecognised><endc>" or
                             * ":ts<unrecognised>:" */
                            parsestate.varSpace = tstr[2];
                            cp = tstr + 3;
                        } else if (tstr[2] == endc || tstr[2] == ':') {
                            /* ":ts<endc>" or ":ts:" */
                            parsestate.varSpace = 0; /* no separator */
                            cp = tstr + 2;
                        } else if (tstr[2] == '\\') {
                            switch (tstr[3]) {
                            case 'n':
                                parsestate.varSpace = '\n';
                                cp = tstr + 4;
                                break;
                            case 't':
                                parsestate.varSpace = '\t';
                                cp = tstr + 4;
                                break;
                            default:
                                if (isdigit((unsigned char)tstr[3])) {
                                    char *ep;

                                    parsestate.varSpace =
                                        strtoul(&tstr[3], &ep, 0);
                                    if (*ep != ':' && *ep != endc)
                                        goto bad_modifier;
                                    cp = ep;
                                } else {
                                    /*
                                     * ":ts<backslash><unrecognised>".
                                     */
                                    goto bad_modifier;
                                }
                                break;
                            }
                        } else {
                            /*
                             * Found ":ts<unrecognised><unrecognised>".
                             */
                            goto bad_modifier;
                        }

                        termc = *cp;

                        /*
                         * We cannot be certain that VarModify
                         * will be used - even if there is a
                         * subsequent modifier, so do a no-op
                         * VarSubstitute now to for str to be
                         * re-expanded without the spaces.
                         */
                        pattern.flags = VAR_SUB_ONE;
                        pattern.lhs = pattern.rhs = "\032";
                        pattern.leftLen = pattern.rightLen = 1;

                        newStr = VarModify(ctxt, &parsestate, nstr,
                                           VarSubstitute,
                                           &pattern);
                    } else if (tstr[2] == endc || tstr[2] == ':') {
                        /*
                         * Check for two-character options:
                         * ":tu", ":tl"
                         */
                        if (tstr[1] == 'u' || tstr[1] == 'l') {
                            newStr = VarChangeCase(nstr, (tstr[1] == 'u'));
                            cp = tstr + 2;
                            termc = *cp;
                        } else if (tstr[1] == 'W' || tstr[1] == 'w') {
                            parsestate.oneBigWord = (tstr[1] == 'W');
                            newStr = nstr;
                            cp = tstr + 2;
                            termc = *cp;
                        } else {
                            /* Found ":t<unrecognised>:" or
                             * ":t<unrecognised><endc>". */
                            goto bad_modifier;
                        }
                    } else {
                        /*
                         * Found ":t<unrecognised><unrecognised>".
                         */
                        goto bad_modifier;
                    }
                } else {
                    /*
                     * Found ":t<endc>" or ":t:".
                     */
                    goto bad_modifier;
                }
                break;
            }
        case 'N':
        case 'M':
            {
                char    *pattern;
                const char *endpat; /* points just after end of pattern */
                char    *cp2;
                Boolean copy;   /* pattern should be, or has been, copied */
                Boolean needSubst;
                int nest;

                copy = FALSE;
                needSubst = FALSE;
                nest = 1;
                /*
                 * In the loop below, ignore ':' unless we are at
                 * (or back to) the original brace level.
                 * XXX This will likely not work right if $() and ${}
                 * are intermixed.
                 */
                for (cp = tstr + 1;
                     *cp != '\0' && !(*cp == ':' && nest == 1);
                     cp++)
                    {
                        if (*cp == '\\' &&
                            (cp[1] == ':' ||
                             cp[1] == endc || cp[1] == startc)) {
                            if (!needSubst) {
                                copy = TRUE;
                            }
                            cp++;
                            continue;
                        }
                        if (*cp == '$') {
                            needSubst = TRUE;
                        }
                        if (*cp == '(' || *cp == '{')
                            ++nest;
                        if (*cp == ')' || *cp == '}') {
                            --nest;
                            if (nest == 0)
                                break;
                        }
                    }
                termc = *cp;
                endpat = cp;
                if (copy) {
                    /*
                     * Need to compress the \:'s out of the pattern, so
                     * allocate enough room to hold the uncompressed
                     * pattern (note that cp started at tstr+1, so
                     * cp - tstr takes the null byte into account) and
                     * compress the pattern into the space.
                     */
                    pattern = bmake_malloc(cp - tstr);
                    for (cp2 = pattern, cp = tstr + 1;
                         cp < endpat;
                         cp++, cp2++)
                        {
                            if ((*cp == '\\') && (cp+1 < endpat) &&
                                (cp[1] == ':' || cp[1] == endc)) {
                                cp++;
                            }
                            *cp2 = *cp;
                        }
                    *cp2 = '\0';
                    endpat = cp2;
                } else {
                    /*
                     * Either Var_Subst or VarModify will need a
                     * nul-terminated string soon, so construct one now.
                     */
                    pattern = bmake_strndup(tstr+1, endpat - (tstr + 1));
                }
                if (needSubst) {
                    /*
                     * pattern contains embedded '$', so use Var_Subst to
                     * expand it.
                     */
                    cp2 = pattern;
                    pattern = Var_Subst(NULL, cp2, ctxt, errnum);
                    free(cp2);
                }
                if (DEBUG(VAR))
                    fprintf(debug_file, "Pattern for [%s] is [%s]\n", nstr,
                        pattern);
                if (*tstr == 'M') {
                    newStr = VarModify(ctxt, &parsestate, nstr, VarMatch,
                                       pattern);
                } else {
                    newStr = VarModify(ctxt, &parsestate, nstr, VarNoMatch,
                                       pattern);
                }
                free(pattern);
                break;
            }
        case 'S':
            {
                VarPattern          pattern;
                Var_Parse_State tmpparsestate;

                pattern.flags = 0;
                tmpparsestate = parsestate;
                delim = tstr[1];
                tstr += 2;

                /*
                 * If pattern begins with '^', it is anchored to the
                 * start of the word -- skip over it and flag pattern.
                 */
                if (*tstr == '^') {
                    pattern.flags |= VAR_MATCH_START;
                    tstr += 1;
                }

                cp = tstr;
                if ((pattern.lhs = VarGetPattern(ctxt, &parsestate, errnum,
                                                 &cp, delim,
                                                 &pattern.flags,
                                                 &pattern.leftLen,
                                                 NULL)) == NULL)
                    goto cleanup;

                if ((pattern.rhs = VarGetPattern(ctxt, &parsestate, errnum,
                                                 &cp, delim, NULL,
                                                 &pattern.rightLen,
                                                 &pattern)) == NULL)
                    goto cleanup;

                /*
                 * Check for global substitution. If 'g' after the final
                 * delimiter, substitution is global and is marked that
                 * way.
                 */
                for (;; cp++) {
                    switch (*cp) {
                    case 'g':
                        pattern.flags |= VAR_SUB_GLOBAL;
                        continue;
                    case '1':
                        pattern.flags |= VAR_SUB_ONE;
                        continue;
                    case 'W':
                        tmpparsestate.oneBigWord = TRUE;
                        continue;
                    }
                    break;
                }

                termc = *cp;
                newStr = VarModify(ctxt, &tmpparsestate, nstr,
                                   VarSubstitute,
                                   &pattern);

                /*
                 * Free the two strings.
                 */
                free(UNCONST(pattern.lhs));
                free(UNCONST(pattern.rhs));
                delim = '\0';
                break;
            }
        case '?':
            {
                VarPattern      pattern;
                Boolean value;

                /* find ':', and then substitute accordingly */

                pattern.flags = 0;

                cp = ++tstr;
                delim = ':';
                if ((pattern.lhs = VarGetPattern(ctxt, &parsestate, errnum,
                                                 &cp, delim, NULL,
                                                 &pattern.leftLen,
                                                 NULL)) == NULL)
                    goto cleanup;

                /* BROPEN or PROPEN */
                delim = endc;
                if ((pattern.rhs = VarGetPattern(ctxt, &parsestate, errnum,
                                                 &cp, delim, NULL,
                                                 &pattern.rightLen,
                                                 NULL)) == NULL)
                    goto cleanup;

                termc = *--cp;
                delim = '\0';
                if (Cond_EvalExpression(NULL, v->name, &value, 0)
                    == COND_INVALID) {
                    Error("Bad conditional expression `%s' in %s?%s:%s",
                          v->name, v->name, pattern.lhs, pattern.rhs);
                    goto cleanup;
                }

                if (value) {
                    newStr = UNCONST(pattern.lhs);
                    free(UNCONST(pattern.rhs));
                } else {
                    newStr = UNCONST(pattern.rhs);
                    free(UNCONST(pattern.lhs));
                }
                if (v->flags & VAR_JUNK) {
                    v->flags |= VAR_KEEP;
                }
                break;
            }
#ifndef NO_REGEX
        case 'C':
            {
                VarREPattern    pattern;
                char           *re;
                int             error;
                Var_Parse_State tmpparsestate;

                pattern.flags = 0;
                tmpparsestate = parsestate;
                delim = tstr[1];
                tstr += 2;

                cp = tstr;

                if ((re = VarGetPattern(ctxt, &parsestate, errnum, &cp, delim,
                                        NULL, NULL, NULL)) == NULL)
                    goto cleanup;

                if ((pattern.replace = VarGetPattern(ctxt, &parsestate,
                                                     errnum, &cp, delim, NULL,
                                                     NULL, NULL)) == NULL){
                    free(re);
                    goto cleanup;
                }

                for (;; cp++) {
                    switch (*cp) {
                    case 'g':
                        pattern.flags |= VAR_SUB_GLOBAL;
                        continue;
                    case '1':
                        pattern.flags |= VAR_SUB_ONE;
                        continue;
                    case 'W':
                        tmpparsestate.oneBigWord = TRUE;
                        continue;
                    }
                    break;
                }

                termc = *cp;

                error = regcomp(&pattern.re, re, REG_EXTENDED);
                free(re);
                if (error)  {
                    *lengthPtr = cp - start + 1;
                    VarREError(error, &pattern.re, "RE substitution error");
                    free(pattern.replace);
                    goto cleanup;
                }

                pattern.nsub = pattern.re.re_nsub + 1;
                if (pattern.nsub < 1)
                    pattern.nsub = 1;
                if (pattern.nsub > 10)
                    pattern.nsub = 10;
                pattern.matches = bmake_malloc(pattern.nsub *
                                          sizeof(regmatch_t));
                newStr = VarModify(ctxt, &tmpparsestate, nstr,
                                   VarRESubstitute,
                                   &pattern);
                regfree(&pattern.re);
                free(pattern.replace);
                free(pattern.matches);
                delim = '\0';
                break;
            }
#endif
        case 'Q':
            if (tstr[1] == endc || tstr[1] == ':') {
                newStr = VarQuote(nstr);
                cp = tstr + 1;
                termc = *cp;
                break;
            }
            goto default_case;
        case 'T':
            if (tstr[1] == endc || tstr[1] == ':') {
                newStr = VarModify(ctxt, &parsestate, nstr, VarTail,
                                   NULL);
                cp = tstr + 1;
                termc = *cp;
                break;
            }
            goto default_case;
        case 'H':
            if (tstr[1] == endc || tstr[1] == ':') {
                newStr = VarModify(ctxt, &parsestate, nstr, VarHead,
                                   NULL);
                cp = tstr + 1;
                termc = *cp;
                break;
            }
            goto default_case;
        case 'E':
            if (tstr[1] == endc || tstr[1] == ':') {
                newStr = VarModify(ctxt, &parsestate, nstr, VarSuffix,
                                   NULL);
                cp = tstr + 1;
                termc = *cp;
                break;
            }
            goto default_case;
        case 'R':
            if (tstr[1] == endc || tstr[1] == ':') {
                newStr = VarModify(ctxt, &parsestate, nstr, VarRoot,
                                   NULL);
                cp = tstr + 1;
                termc = *cp;
                break;
            }
            goto default_case;
        case 'O':
            {
                char otype;

                cp = tstr + 1;  /* skip to the rest in any case */
                if (tstr[1] == endc || tstr[1] == ':') {
                    otype = 's';
                    termc = *cp;
                } else if ( (tstr[1] == 'x') &&
                            (tstr[2] == endc || tstr[2] == ':') ) {
                    otype = tstr[1];
                    cp = tstr + 2;
                    termc = *cp;
                } else {
                    goto bad_modifier;
                }
                newStr = VarOrder(nstr, otype);
                break;
            }
        case 'u':
            if (tstr[1] == endc || tstr[1] == ':') {
                newStr = VarUniq(nstr);
                cp = tstr + 1;
                termc = *cp;
                break;
            }
            goto default_case;
#ifdef SUNSHCMD
        case 's':
            if (tstr[1] == 'h' && (tstr[2] == endc || tstr[2] == ':')) {
                const char *emsg;
                newStr = Cmd_Exec(nstr, &emsg);
                if (emsg)
                    Error(emsg, nstr);
                cp = tstr + 2;
                termc = *cp;
                break;
            }
            goto default_case;
#endif
        default:
        default_case:
        {
#ifdef SYSVVARSUB
            /*
             * This can either be a bogus modifier or a System-V
             * substitution command.
             */
            VarPattern      pattern;
            Boolean         eqFound;

            pattern.flags = 0;
            eqFound = FALSE;
            /*
             * First we make a pass through the string trying
             * to verify it is a SYSV-make-style translation:
             * it must be: <string1>=<string2>)
             */
            cp = tstr;
            cnt = 1;
            while (*cp != '\0' && cnt) {
                if (*cp == '=') {
                    eqFound = TRUE;
                    /* continue looking for endc */
                }
                else if (*cp == endc)
                    cnt--;
                else if (*cp == startc)
                    cnt++;
                if (cnt)
                    cp++;
            }
            if (*cp == endc && eqFound) {

                /*
                 * Now we break this sucker into the lhs and
                 * rhs. We must null terminate them of course.
                 */
                delim='=';
                cp = tstr;
                if ((pattern.lhs = VarGetPattern(ctxt, &parsestate,
                                                 errnum, &cp, delim, &pattern.flags,
                                                 &pattern.leftLen, NULL)) == NULL)
                    goto cleanup;
                delim = endc;
                if ((pattern.rhs = VarGetPattern(ctxt, &parsestate,
                                                 errnum, &cp, delim, NULL, &pattern.rightLen,
                                                 &pattern)) == NULL)
                    goto cleanup;

                /*
                 * SYSV modifications happen through the whole
                 * string. Note the pattern is anchored at the end.
                 */
                termc = *--cp;
                delim = '\0';
                newStr = VarModify(ctxt, &parsestate, nstr,
                                   VarSYSVMatch,
                                   &pattern);
                free(UNCONST(pattern.lhs));
                free(UNCONST(pattern.rhs));
            } else
#endif
                {
                    Error("Unknown modifier '%c'", *tstr);
                    for (cp = tstr+1;
                         *cp != ':' && *cp != endc && *cp != '\0';
                         cp++)
                        continue;
                    termc = *cp;
                    newStr = var_Error;
                }
            }
        }
        if (DEBUG(VAR)) {
            fprintf(debug_file, "Result of :%c is \"%s\"\n", modifier, newStr);
        }

        if (newStr != nstr) {
            if (*freePtr) {
                free(nstr);
                *freePtr = NULL;
            }
            nstr = newStr;
            if (nstr != var_Error && nstr != varNoError) {
                *freePtr = nstr;
            }
        }
        if (termc == '\0' && endc != '\0') {
            Error("Unclosed variable specification (expecting '%c') for \"%s\" (value \"%s\") modifier %c", endc, v->name, nstr, modifier);
        } else if (termc == ':') {
            cp++;
        }
        tstr = cp;
    }
 out:
    *lengthPtr = tstr - start;
    return (nstr);

 bad_modifier:
    /* "{(" */
    Error("Bad modifier `:%.*s' for %s", (int)strcspn(tstr, ":)}"), tstr,
          v->name);

 cleanup:
    *lengthPtr = cp - start;
    if (delim != '\0')
        Error("Unclosed substitution for %s (%c missing)",
              v->name, delim);
    if (*freePtr) {
        free(*freePtr);
        *freePtr = NULL;
    }
    return (var_Error);
}

/*-
 *-----------------------------------------------------------------------
 * Var_Parse --
 *      Given the start of a variable invocation, extract the variable
 *      name and find its value, then modify it according to the
 *      specification.
 *
 * Input:
 *      str             The string to parse
 *      ctxt            The context for the variable
 *      errnum          TRUE if undefined variables are an error
 *      lengthPtr       OUT: The length of the specification
 *      freePtr         OUT: Non-NULL if caller should free *freePtr
 *
 * Results:
 *      The (possibly-modified) value of the variable or var_Error if the
 *      specification is invalid. The length of the specification is
 *      placed in *lengthPtr (for invalid specifications, this is just
 *      2...?).
 *      If *freePtr is non-NULL then it's a pointer that the caller
 *      should pass to free() to free memory used by the result.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
/* coverity[+alloc : arg-*4] */
char *
Var_Parse(const char *str, GNode *ctxt, Boolean errnum, int *lengthPtr,
          void **freePtr)
{
    const char     *tstr;       /* Pointer into str */
    Var            *v;          /* Variable in invocation */
    Boolean         haveModifier;/* TRUE if have modifiers for the variable */
    char            endc;       /* Ending character when variable in parens
                                 * or braces */
    char            startc;     /* Starting character when variable in parens
                                 * or braces */
    int             vlen;       /* Length of variable name */
    const char     *start;      /* Points to original start of str */
    char           *nstr;       /* New string, used during expansion */
    Boolean         dynamic;    /* TRUE if the variable is local and we're
                                 * expanding it in a non-local context. This
                                 * is done to support dynamic sources. The
                                 * result is just the invocation, unaltered */
    Var_Parse_State parsestate; /* Flags passed to helper functions */
    char          name[2];

    *freePtr = NULL;
    dynamic = FALSE;
    start = str;
    parsestate.oneBigWord = FALSE;
    parsestate.varSpace = ' ';  /* word separator */

    startc = str[1];
    if (startc != PROPEN && startc != BROPEN) {
        /*
         * If it's not bounded by braces of some sort, life is much simpler.
         * We just need to check for the first character and return the
         * value if it exists.
         */

        /* Error out some really stupid names */
        if (startc == '\0' || strchr(")}:$", startc)) {
            *lengthPtr = 1;
            return var_Error;
        }
        name[0] = startc;
        name[1] = '\0';

        v = VarFind(name, ctxt, FIND_ENV | FIND_GLOBAL | FIND_CMD);
        if (v == NULL) {
            *lengthPtr = 2;

            if ((ctxt == VAR_CMD) || (ctxt == VAR_GLOBAL)) {
                /*
                 * If substituting a local variable in a non-local context,
                 * assume it's for dynamic source stuff. We have to handle
                 * this specially and return the longhand for the variable
                 * with the dollar sign escaped so it makes it back to the
                 * caller. Only four of the local variables are treated
                 * specially as they are the only four that will be set
                 * when dynamic sources are expanded.
                 */
                switch (str[1]) {
                    case '@':
                        return UNCONST("$(.TARGET)");
                    case '%':
                        return UNCONST("$(.ARCHIVE)");
                    case '*':
                        return UNCONST("$(.PREFIX)");
                    case '!':
                        return UNCONST("$(.MEMBER)");
                }
            }
            /*
             * Error
             */
            return (errnum ? var_Error : varNoError);
        } else {
            haveModifier = FALSE;
            tstr = &str[1];
            endc = str[1];
        }
    } else {
        Buffer buf;     /* Holds the variable name */

        endc = startc == PROPEN ? PRCLOSE : BRCLOSE;
        Buf_Init(&buf, 0);

        /*
         * Skip to the end character or a colon, whichever comes first.
         */
        for (tstr = str + 2;
             *tstr != '\0' && *tstr != endc && *tstr != ':';
             tstr++)
        {
            /*
             * A variable inside a variable, expand
             */
            if (*tstr == '$') {
                int rlen;
                void *freeIt;
                char *rval = Var_Parse(tstr, ctxt, errnum, &rlen, &freeIt);
                if (rval != NULL) {
                    Buf_AddBytes(&buf, strlen(rval), rval);
                }
                if (freeIt)
                    free(freeIt);
                tstr += rlen - 1;
            }
            else
                Buf_AddByte(&buf, *tstr);
        }
        if (*tstr == ':') {
            haveModifier = TRUE;
        } else if (*tstr != '\0') {
            haveModifier = FALSE;
        } else {
            /*
             * If we never did find the end character, return NULL
             * right now, setting the length to be the distance to
             * the end of the string, since that's what make does.
             */
            *lengthPtr = tstr - str;
            Buf_Destroy(&buf, TRUE);
            return (var_Error);
        }
        str = Buf_GetAll(&buf, &vlen);

        /*
         * At this point, str points into newly allocated memory from
         * buf, containing only the name of the variable.
         *
         * start and tstr point into the const string that was pointed
         * to by the original value of the str parameter.  start points
         * to the '$' at the beginning of the string, while tstr points
         * to the char just after the end of the variable name -- this
         * will be '\0', ':', PRCLOSE, or BRCLOSE.
         */

        v = VarFind(str, ctxt, FIND_ENV | FIND_GLOBAL | FIND_CMD);
        /*
         * Check also for bogus D and F forms of local variables since we're
         * in a local context and the name is the right length.
         */
        if ((v == NULL) && (ctxt != VAR_CMD) && (ctxt != VAR_GLOBAL) &&
                (vlen == 2) && (str[1] == 'F' || str[1] == 'D') &&
                strchr("@%*!<>", str[0]) != NULL) {
            /*
             * Well, it's local -- go look for it.
             */
            name[0] = *str;
            name[1] = '\0';
            v = VarFind(name, ctxt, 0);

            if (v != NULL) {
                /*
                 * No need for nested expansion or anything, as we're
                 * the only one who sets these things and we sure don't
                 * but nested invocations in them...
                 */
                nstr = Buf_GetAll(&v->val, NULL);

                if (str[1] == 'D') {
                    nstr = VarModify(ctxt, &parsestate, nstr, VarHead,
                                    NULL);
                } else {
                    nstr = VarModify(ctxt, &parsestate, nstr, VarTail,
                                    NULL);
                }
                /*
                 * Resulting string is dynamically allocated, so
                 * tell caller to free it.
                 */
                *freePtr = nstr;
                *lengthPtr = tstr-start+1;
                Buf_Destroy(&buf, TRUE);
                VarFreeEnv(v, TRUE);
                return nstr;
            }
        }

        if (v == NULL) {
            if (((vlen == 1) ||
                 (((vlen == 2) && (str[1] == 'F' || str[1] == 'D')))) &&
                ((ctxt == VAR_CMD) || (ctxt == VAR_GLOBAL)))
            {
                /*
                 * If substituting a local variable in a non-local context,
                 * assume it's for dynamic source stuff. We have to handle
                 * this specially and return the longhand for the variable
                 * with the dollar sign escaped so it makes it back to the
                 * caller. Only four of the local variables are treated
                 * specially as they are the only four that will be set
                 * when dynamic sources are expanded.
                 */
                switch (*str) {
                    case '@':
                    case '%':
                    case '*':
                    case '!':
                        dynamic = TRUE;
                        break;
                }
            } else if ((vlen > 2) && (*str == '.') &&
                       isupper((unsigned char) str[1]) &&
                       ((ctxt == VAR_CMD) || (ctxt == VAR_GLOBAL)))
            {
                int     len;

                len = vlen - 1;
                if ((strncmp(str, ".TARGET", len) == 0) ||
                    (strncmp(str, ".ARCHIVE", len) == 0) ||
                    (strncmp(str, ".PREFIX", len) == 0) ||
                    (strncmp(str, ".MEMBER", len) == 0))
                {
                    dynamic = TRUE;
                }
            }

            if (!haveModifier) {
                /*
                 * No modifiers -- have specification length so we can return
                 * now.
                 */
                *lengthPtr = tstr - start + 1;
                if (dynamic) {
                    char *pstr = bmake_strndup(start, *lengthPtr);
                    *freePtr = pstr;
                    Buf_Destroy(&buf, TRUE);
                    return(pstr);
                } else {
                    Buf_Destroy(&buf, TRUE);
                    return (errnum ? var_Error : varNoError);
                }
            } else {
                /*
                 * Still need to get to the end of the variable specification,
                 * so kludge up a Var structure for the modifications
                 */
                v = bmake_malloc(sizeof(Var));
                v->name = UNCONST(str);
                Buf_Init(&v->val, 1);
                v->flags = VAR_JUNK;
                Buf_Destroy(&buf, FALSE);
            }
        } else
            Buf_Destroy(&buf, TRUE);
    }

    if (v->flags & VAR_IN_USE) {
        Fatal("Variable %s is recursive.", v->name);
        /*NOTREACHED*/
    } else {
        v->flags |= VAR_IN_USE;
    }
    /*
     * Before doing any modification, we have to make sure the value
     * has been fully expanded. If it looks like recursion might be
     * necessary (there's a dollar sign somewhere in the variable's value)
     * we just call Var_Subst to do any other substitutions that are
     * necessary. Note that the value returned by Var_Subst will have
     * been dynamically-allocated, so it will need freeing when we
     * return.
     */
    nstr = Buf_GetAll(&v->val, NULL);
    if (strchr(nstr, '$') != NULL) {
        nstr = Var_Subst(NULL, nstr, ctxt, errnum);
        *freePtr = nstr;
    }

    v->flags &= ~VAR_IN_USE;

    if ((nstr != NULL) && haveModifier) {
        int used;
        /*
         * Skip initial colon.
         */
        tstr++;

        nstr = ApplyModifiers(nstr, tstr, startc, endc,
                              v, ctxt, errnum, &used, freePtr);
        tstr += used;
    }
    if (*tstr) {
        *lengthPtr = tstr - start + 1;
    } else {
        *lengthPtr = tstr - start;
    }

    if (v->flags & VAR_FROM_ENV) {
        Boolean   destroy = FALSE;

        if (nstr != Buf_GetAll(&v->val, NULL)) {
            destroy = TRUE;
        } else {
            /*
             * Returning the value unmodified, so tell the caller to free
             * the thing.
             */
            *freePtr = nstr;
        }
        VarFreeEnv(v, destroy);
    } else if (v->flags & VAR_JUNK) {
        /*
         * Perform any free'ing needed and set *freePtr to NULL so the caller
         * doesn't try to free a static pointer.
         * If VAR_KEEP is also set then we want to keep str as is.
         */
        if (!(v->flags & VAR_KEEP)) {
            if (*freePtr) {
                free(nstr);
                *freePtr = NULL;
            }
            if (dynamic) {
                nstr = bmake_strndup(start, *lengthPtr);
                *freePtr = nstr;
            } else {
                nstr = var_Error;
            }
        }
        if (nstr != Buf_GetAll(&v->val, NULL))
            Buf_Destroy(&v->val, TRUE);
        free(v->name);
        free(v);
    }
    return (nstr);
}

/*-
 *-----------------------------------------------------------------------
 * Var_Subst  --
 *      Substitute for all variables in the given string in the given context
 *      If undefErr is TRUE, Parse_Error will be called when an undefined
 *      variable is encountered.
 *
 * Input:
 *      var             Named variable || NULL for all
 *      str             the string which to substitute
 *      ctxt            the context wherein to find variables
 *      undefErr        TRUE if undefineds are an error
 *
 * Results:
 *      The resulting string.
 *
 * Side Effects:
 *      None. The old string must be freed by the caller
 *-----------------------------------------------------------------------
 */
char *
Var_Subst(const char *var, const char *str, GNode *ctxt, Boolean undefErr)
{
    Buffer        buf;              /* Buffer for forming things */
    char          *val;             /* Value to substitute for a variable */
    int           length;           /* Length of the variable invocation */
    Boolean       trailingBslash;   /* variable ends in \ */
    void          *freeIt = NULL;    /* Set if it should be freed */
    static Boolean errorReported;   /* Set true if an error has already
                                     * been reported to prevent a plethora
                                     * of messages when recursing */

    Buf_Init(&buf, 0);
    errorReported = FALSE;
    trailingBslash = FALSE;

    while (*str) {
        if (*str == '\n' && trailingBslash)
            Buf_AddByte(&buf, ' ');
        if (var == NULL && (*str == '$') && (str[1] == '$')) {
            /*
             * A dollar sign may be escaped either with another dollar sign.
             * In such a case, we skip over the escape character and store the
             * dollar sign into the buffer directly.
             */
            str++;
            Buf_AddByte(&buf, *str);
            str++;
        } else if (*str != '$') {
            /*
             * Skip as many characters as possible -- either to the end of
             * the string or to the next dollar sign (variable invocation).
             */
            const char  *cp;

            for (cp = str++; *str != '$' && *str != '\0'; str++)
                continue;
            Buf_AddBytes(&buf, str - cp, cp);
        } else {
            if (var != NULL) {
                int expand;
                for (;;) {
                    if (str[1] == '\0') {
                        /* A trailing $ is kind of a special case */
                        Buf_AddByte(&buf, str[0]);
                        str++;
                        expand = FALSE;
                    } else if (str[1] != PROPEN && str[1] != BROPEN) {
                        if (str[1] != *var || strlen(var) > 1) {
                            Buf_AddBytes(&buf, 2, str);
                            str += 2;
                            expand = FALSE;
                        }
                        else
                            expand = TRUE;
                        break;
                    }
                    else {
                        const char *p;

                        /*
                         * Scan up to the end of the variable name.
                         */
                        for (p = &str[2]; *p &&
                             *p != ':' && *p != PRCLOSE && *p != BRCLOSE; p++)
                            if (*p == '$')
                                break;
                        /*
                         * A variable inside the variable. We cannot expand
                         * the external variable yet, so we try again with
                         * the nested one
                         */
                        if (*p == '$') {
                            Buf_AddBytes(&buf, p - str, str);
                            str = p;
                            continue;
                        }

                        if (strncmp(var, str + 2, p - str - 2) != 0 ||
                            var[p - str - 2] != '\0') {
                            /*
                             * Not the variable we want to expand, scan
                             * until the next variable
                             */
                            for (;*p != '$' && *p != '\0'; p++)
                                continue;
                            Buf_AddBytes(&buf, p - str, str);
                            str = p;
                            expand = FALSE;
                        }
                        else
                            expand = TRUE;
                        break;
                    }
                }
                if (!expand)
                    continue;
            }

            val = Var_Parse(str, ctxt, undefErr, &length, &freeIt);

            /*
             * When we come down here, val should either point to the
             * value of this variable, suitably modified, or be NULL.
             * Length should be the total length of the potential
             * variable invocation (from $ to end character...)
             */
            if (val == var_Error || val == varNoError) {
                /*
                 * If performing old-time variable substitution, skip over
                 * the variable and continue with the substitution. Otherwise,
                 * store the dollar sign and advance str so we continue with
                 * the string...
                 */
                if (oldVars) {
                    str += length;
                } else if (undefErr) {
                    /*
                     * If variable is undefined, complain and skip the
                     * variable. The complaint will stop us from doing anything
                     * when the file is parsed.
                     */
                    if (!errorReported) {
                        Parse_Error(PARSE_FATAL,
                                     "Undefined variable \"%.*s\"",length,str);
                    }
                    str += length;
                    errorReported = TRUE;
                } else {
                    Buf_AddByte(&buf, *str);
                    str += 1;
                }
            } else {
                /*
                 * We've now got a variable structure to store in. But first,
                 * advance the string pointer.
                 */
                str += length;

                /*
                 * Copy all the characters from the variable value straight
                 * into the new string.
                 */
                length = strlen(val);
                Buf_AddBytes(&buf, length, val);
                trailingBslash = length > 0 && val[length - 1] == '\\';
            }
            if (freeIt) {
                free(freeIt);
                freeIt = NULL;
            }
        }
    }

    return Buf_Destroy(&buf, FALSE);
}

/*-
 *-----------------------------------------------------------------------
 * Var_GetTail --
 *      Return the tail from each of a list of words. Used to set the
 *      System V local variables.
 *
 * Input:
 *      file            Filename to modify
 *
 * Results:
 *      The resulting string.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
#if 0
char *
Var_GetTail(char *file)
{
    return(VarModify(file, VarTail, NULL));
}

/*-
 *-----------------------------------------------------------------------
 * Var_GetHead --
 *      Find the leading components of a (list of) filename(s).
 *      XXX: VarHead does not replace foo by ., as (sun) System V make
 *      does.
 *
 * Input:
 *      file            Filename to manipulate
 *
 * Results:
 *      The leading components.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
char *
Var_GetHead(char *file)
{
    return(VarModify(file, VarHead, NULL));
}
#endif

/*-
 *-----------------------------------------------------------------------
 * Var_Init --
 *      Initialize the module
 *
 * Results:
 *      None
 *
 * Side Effects:
 *      The VAR_CMD and VAR_GLOBAL contexts are created
 *-----------------------------------------------------------------------
 */
void
Var_Init(void)
{
    VAR_GLOBAL = Targ_NewGN("Global");
    VAR_CMD = Targ_NewGN("Command");

}


void
Var_End(void)
{
}


/****************** PRINT DEBUGGING INFO *****************/
static void
VarPrintVar(void *vp)
{
    Var    *v = (Var *)vp;
    fprintf(debug_file, "%-16s = %s\n", v->name, Buf_GetAll(&v->val, NULL));
}

/*-
 *-----------------------------------------------------------------------
 * Var_Dump --
 *      print all variables in a context
 *-----------------------------------------------------------------------
 */
void
Var_Dump(GNode *ctxt)
{
    Hash_Search search;
    Hash_Entry *h;

    for (h = Hash_EnumFirst(&ctxt->context, &search);
         h != NULL;
         h = Hash_EnumNext(&search)) {
            VarPrintVar(Hash_GetValue(h));
    }
}