[dragonfly.git] / usr.bin / make / var.c

/*
 * Copyright (c) 1988, 1989, 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 * 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.
 *
 * @(#)var.c    8.3 (Berkeley) 3/19/94
 * $FreeBSD: src/usr.bin/make/var.c,v 1.16.2.3 2002/02/27 14:18:57 cjc Exp $
 * $DragonFly: src/usr.bin/make/var.c,v 1.49 2005/01/28 23:25:18 okumoto Exp $
 */

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

#include <ctype.h>
#include <stdlib.h>
#include <string.h>

#include "buf.h"
#include "config.h"
#include "globals.h"
#include "GNode.h"
#include "make.h"
#include "nonints.h"
#include "parse.h"
#include "str.h"
#include "targ.h"
#include "util.h"
#include "var.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 'err' 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 */

static char *VarPossiblyExpand(const char *, GNode *);
static Var *VarFind(const char *, GNode *, int);
static void VarAdd(const char *, const char *, GNode *);
static Var *VarCreate(const char [], const char [], int);
static void VarDestroy(Var *, Boolean);
static char *VarGetPattern(GNode *, int, char **, int, int *, size_t *,
                           VarPattern *);
static char *VarModify(char *,
                       Boolean (*)(const char *, Boolean, Buffer *, void *),
                       void *);
static int VarPrintVar(void *, void *);

/*-
 *-----------------------------------------------------------------------
 * VarCmp  --
 *      See if the given variable matches the named one. Called from
 *      Lst_Find when searching for a variable of a given name.
 *
 * Results:
 *      0 if they match. non-zero otherwise.
 *
 * Side Effects:
 *      none
 *-----------------------------------------------------------------------
 */
static int
VarCmp(const void *v, const void *name)
{
    return (strcmp(name, ((const Var *)v)->name));
}

/*-
 *-----------------------------------------------------------------------
 * VarPossiblyExpand --
 *      Expand a variable name's embedded variables in the given context.
 *
 * Results:
 *      The contents of name, possibly expanded.
 *
 * Side Effects:
 *      The caller must free the new contents or old contents of name.
 *-----------------------------------------------------------------------
 */
static char *
VarPossiblyExpand(const char *name, GNode *ctxt)
{
    if (strchr(name, '$') != NULL)
        return Var_Subst(NULL, name, ctxt, 0);
    else
        return estrdup(name);
}

/*-
 *-----------------------------------------------------------------------
 * VarFind --
 *      Find the given variable in the given context and any other contexts
 *      indicated.
 *
 *      Flags:
 *              FIND_GLOBAL     set means look in the VAR_GLOBAL context too
 *              FIND_CMD        set means to look in the VAR_CMD context too
 *              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)
{
    Boolean             localCheckEnvFirst;
    LstNode             *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[0] == '.' && 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;
        }

    /*
     * Note whether this is one of the specific variables we were told through
     * the -E flag to use environment-variable-override for.
     */
    if (Lst_Find(&envFirstVars, name, (CompareProc *)strcmp) != NULL) {
        localCheckEnvFirst = TRUE;
    } else {
        localCheckEnvFirst = FALSE;
    }

    /*
     * 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 = Lst_Find(&ctxt->context, name, VarCmp);

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

        if ((env = getenv(name)) != NULL) {
            v = VarCreate(name, env, VAR_FROM_ENV);

            return (v);
        } else if ((checkEnvFirst || localCheckEnvFirst) &&
                   (flags & FIND_GLOBAL) && (ctxt != VAR_GLOBAL))
        {
            var = Lst_Find(&VAR_GLOBAL->context, name, VarCmp);
            if (var == NULL) {
                return (NULL);
            } else {
                return (Lst_Datum(var));
            }
        } else {
            return (NULL);
        }
    } else if (var == NULL) {
        return (NULL);
    } else {
        return (Lst_Datum(var));
    }
}

/*-
 *-----------------------------------------------------------------------
 * VarAdd  --
 *      Add a new variable of name name and value val to the given context.
 *
 * 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)
{
    Lst_AtFront(&ctxt->context, VarCreate(name, val, 0));

    DEBUGF(VAR, ("%s:%s = %s\n", ctxt->name, name, val));
}

/*
 * Create a Var object.
 *
 * @param name          Name of variable.
 * @param value         Value of variable.
 * @param flags         Flags set on variable.
 */
static Var *
VarCreate(const char name[], const char value[], int flags)
{
    Var *v;

    v = emalloc(sizeof(Var));
    v->name     = estrdup(name);
    v->val      = Buf_Init(0);
    v->flags    = flags;

    if (value != NULL) {
        Buf_Append(v->val, value);
    }
    return (v);
}

/*
 * Destroy a Var object.
 *
 * @param v     Object to destroy.
 * @param f     true if internal buffer in Buffer object is to be
 *              removed.
 */
static void
VarDestroy(Var *v, Boolean f)
{
    Buf_Destroy(v->val, f);
    free(v->name);
    free(v);
}

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

    DEBUGF(VAR, ("%s:delete %s\n", ctxt->name, name));
    ln = Lst_Find(&ctxt->context, name, VarCmp);
    if (ln != NULL) {
        VarDestroy(Lst_Datum(ln), TRUE);
        Lst_Remove(&ctxt->context, ln);
    }
}

/*-
 *-----------------------------------------------------------------------
 * Var_Set --
 *      Set the variable name to the value val in the given context.
 *
 * 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 $(<).
 *-----------------------------------------------------------------------
 */
void
Var_Set(const char *name, const char *val, GNode *ctxt)
{
    Var         *v;
    char        *n;

    /*
     * 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...
     */
    n = VarPossiblyExpand(name, ctxt);
    v = VarFind(n, ctxt, 0);
    if (v == NULL) {
        VarAdd(n, val, ctxt);
    } else {
        Buf_Clear(v->val);
        Buf_Append(v->val, val);

        DEBUGF(VAR, ("%s:%s = %s\n", ctxt->name, n, val));
    }
    /*
     * Any variables given on the command line are automatically exported
     * to the environment (as per POSIX standard)
     */
    if (ctxt == VAR_CMD || (v != (Var *)NULL && (v->flags & VAR_TO_ENV))) {
        setenv(n, val, 1);
    }
    free(n);
}

/*
 * Var_SetEnv --
 *      Set the VAR_TO_ENV flag on a variable
 */
void
Var_SetEnv(const char *name, GNode *ctxt)
{
    Var *v;

    v = VarFind(name, ctxt, FIND_CMD|FIND_GLOBAL|FIND_ENV);
    if (v) {
        if ((v->flags & VAR_TO_ENV) == 0) {
            v->flags |= VAR_TO_ENV;
            setenv(v->name, Buf_GetAll(v->val, NULL), 1);
        }
    } else {
        Error("Cannot set environment flag on non-existant variable %s", name);
    }
}

/*-
 *-----------------------------------------------------------------------
 * Var_Append --
 *      The variable of the given name has the given value appended to it in
 *      the given context.
 *
 * 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;
    char        *n;

    n = VarPossiblyExpand(name, ctxt);
    v = VarFind(n, ctxt, (ctxt == VAR_GLOBAL) ? FIND_ENV : 0);
    if (v == NULL) {
        VarAdd(n, val, ctxt);
    } else {
        Buf_AddByte(v->val, (Byte)' ');
        Buf_Append(v->val, val);

        DEBUGF(VAR, ("%s:%s = %s\n", ctxt->name, n,
               (char *)Buf_GetAll(v->val, (size_t *)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;
            Lst_AtFront(&ctxt->context, v);
        }
    }
    free(n);
}

/*-
 *-----------------------------------------------------------------------
 * Var_Exists --
 *      See if the given variable exists.
 *
 * Results:
 *      TRUE if it does, FALSE if it doesn't
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
Boolean
Var_Exists(const char *name, GNode *ctxt)
{
    Var         *v;
    char        *n;

    n = VarPossiblyExpand(name, ctxt);
    v = VarFind(n, ctxt, FIND_CMD|FIND_GLOBAL|FIND_ENV);
    free(n);

    if (v == NULL) {
        return (FALSE);
    } else if (v->flags & VAR_FROM_ENV) {
        VarDestroy(v, TRUE);
    }
    return (TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * Var_Value --
 *      Return the value of the named variable in the given context
 *
 * 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;
    char        *n;

    n = VarPossiblyExpand(name, ctxt);
    v = VarFind(n, ctxt, FIND_ENV | FIND_GLOBAL | FIND_CMD);
    free(n);
    *frp = NULL;
    if (v != NULL) {
        char *p = (char *)Buf_GetAll(v->val, (size_t *)NULL);

        if (v->flags & VAR_FROM_ENV) {
            VarDestroy(v, FALSE);
            *frp = p;
        }
        return (p);
    } else {
        return (NULL);
    }
}

/*-
 *-----------------------------------------------------------------------
 * VarModify --
 *      Modify each of the words of the passed string using the given
 *      function. Used to implement all modifiers.
 *
 * Results:
 *      A string of all the words modified appropriately.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
static char *
VarModify(char *str, Boolean (*modProc)(const 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 [first word does not count] */
    int ac, i;

    buf = Buf_Init(0);
    addSpace = FALSE;

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

    for (i = 1; i < ac; i++)
        addSpace = (*modProc)(av[i], addSpace, buf, datum);

    Buf_AddByte(buf, '\0');
    str = (char *)Buf_GetAll(buf, (size_t *)NULL);
    Buf_Destroy(buf, FALSE);
    return (str);
}

/*-
 *-----------------------------------------------------------------------
 * VarSortWords --
 *      Sort the words in the string.
 *
 * Input:
 *      str             String whose words should be sorted
 *      cmp             A comparison function to control the ordering
 *
 * Results:
 *      A string containing the words sorted
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
static char *
VarSortWords(char *str, int (*cmp)(const void *, const void *))
{
        Buffer *buf;
        char **av;
        int ac, i;

        buf = Buf_Init(0);
        av = brk_string(str, &ac, FALSE);
        qsort(av + 1, ac - 1, sizeof(char *), cmp);
        for (i = 1; i < ac; i++) {
                Buf_Append(buf, av[i]);
                Buf_AddByte(buf, (Byte)((i < ac - 1) ? ' ' : '\0'));
        }
        str = (char *)Buf_GetAll(buf, (size_t *)NULL);
        Buf_Destroy(buf, FALSE);
        return (str);
}

static int
SortIncreasing(const void *l, const void *r)
{
        return (strcmp(*(const char* const*)l, *(const char* const*)r));
}

/*-
 *-----------------------------------------------------------------------
 * 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, int err, char **tstr, int delim, int *flags,
    size_t *length, VarPattern *pattern)
{
    char *cp;
    Buffer *buf = Buf_Init(0);
    size_t junk;

    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, $, and \, but don't
     * touch other backslashes.
     */
    for (cp = *tstr; *cp && (*cp != delim); cp++) {
        if (IS_A_MATCH(cp, delim)) {
            Buf_AddByte(buf, (Byte)cp[1]);
            cp++;
        } else if (*cp == '$') {
            if (cp[1] == delim) {
                if (flags == NULL)
                    Buf_AddByte(buf, (Byte)*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;
                    size_t len;
                    Boolean freeIt;

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

                    if (*cp2 == '(' || *cp2 == '{') {
                        /*
                         * 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 == '(') ? ')' : '}';
                        int depth = 1;

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

    Buf_AddByte(buf, (Byte)'\0');

    if (*cp != delim) {
        *tstr = cp;
        *length = 0;
        return (NULL);
    } else {
        *tstr = ++cp;
        cp = (char *)Buf_GetAll(buf, length);
        *length -= 1;   /* Don't count the NULL */
        Buf_Destroy(buf, FALSE);
        return (cp);
    }
}

/*-
 *-----------------------------------------------------------------------
 * Var_Quote --
 *      Quote shell meta-characters in the string
 *
 * Results:
 *      The quoted string
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
char *
Var_Quote(const char *str)
{
    Buffer       *buf;
    /* This should cover most shells :-( */
    static char meta[] = "\n \t'`\";&<>()|*?{}[]\\$!#^~";
    char          *ret;

    buf = Buf_Init(MAKE_BSIZE);
    for (; *str; str++) {
        if (strchr(meta, *str) != NULL)
            Buf_AddByte(buf, (Byte)'\\');
        Buf_AddByte(buf, (Byte)*str);
    }
    Buf_AddByte(buf, (Byte)'\0');
    ret = Buf_GetAll(buf, NULL);
    Buf_Destroy(buf, FALSE);
    return (ret);
}

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

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

/*-
 *-----------------------------------------------------------------------
 * Var_Parse --
 *      Given the start of a variable invocation, extract the variable
 *      name and find its value, then modify it according to the
 *      specification.
 *
 * 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 to skip the '$' and the following letter, or 1 if '$' was the
 *      last character in the string).
 *      A Boolean in *freePtr telling whether the returned string should
 *      be freed by the caller.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
char *
Var_Parse(char *str, GNode *ctxt, Boolean err, size_t *lengthPtr, Boolean *freePtr)
{
    char            *tstr;      /* Pointer into str */
    Var             *v;         /* Variable in invocation */
    char            *cp;        /* Secondary pointer into str (place marker
                                 * for tstr) */
    Boolean         haveModifier;/* TRUE if have modifiers for the variable */
    char            endc;       /* Ending character when variable in parens
                                 * or braces */
    char            startc=0;   /* Starting character when variable in parens
                                 * or braces */
    int             cnt;        /* Used to count brace pairs when variable in
                                 * in parens or braces */
    char            *start;
    char             delim;
    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 */
    int         vlen;           /* length of variable name, after embedded variable
                                 * expansion */

    *freePtr = FALSE;
    dynamic = FALSE;
    start = str;

    if (str[1] != '(' && str[1] != '{') {
        /*
         * 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.
         */
        char      name[2];

        name[0] = str[1];
        name[1] = '\0';

        v = VarFind(name, ctxt, FIND_ENV | FIND_GLOBAL | FIND_CMD);
        if (v == (Var *)NULL) {
            if (str[1] != '\0')
                *lengthPtr = 2;
            else
                *lengthPtr = 1;

            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.
                 */
                /* XXX: It looks like $% and $! are reversed here */
                switch (str[1]) {
                    case '@':
                        return ("$(.TARGET)");
                    case '%':
                        return ("$(.ARCHIVE)");
                    case '*':
                        return ("$(.PREFIX)");
                    case '!':
                        return ("$(.MEMBER)");
                    default:
                        break;
                }
            }
            /*
             * Error
             */
            return (err ? var_Error : varNoError);
        } else {
            haveModifier = FALSE;
            tstr = &str[1];
            endc = str[1];
        }
    } else {
        /* build up expanded variable name in this buffer */
        Buffer  *buf = Buf_Init(MAKE_BSIZE);

        startc = str[1];
        endc = startc == '(' ? ')' : '}';

        /*
         * Skip to the end character or a colon, whichever comes first,
         * replacing embedded variables as we go.
         */
        for (tstr = str + 2; *tstr != '\0' && *tstr != endc && *tstr != ':'; tstr++)
                if (*tstr == '$') {
                        size_t rlen;
                        Boolean rfree;
                        char*   rval = Var_Parse(tstr, ctxt, err, &rlen, &rfree);

                        if (rval == var_Error) {
                                Fatal("Error expanding embedded variable.");
                        } else if (rval != NULL) {
                                Buf_Append(buf, rval);
                                if (rfree)
                                        free(rval);
                        }
                        tstr += rlen - 1;
                } else
                        Buf_AddByte(buf, (Byte)*tstr);

        if (*tstr == '\0') {
            /*
             * 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;
            return (var_Error);
        }

        haveModifier = (*tstr == ':');
        *tstr = '\0';

        Buf_AddByte(buf, (Byte)'\0');
        str = Buf_GetAll(buf, (size_t *)NULL);
        vlen = strlen(str);

        v = VarFind(str, ctxt, FIND_ENV | FIND_GLOBAL | FIND_CMD);
        if ((v == (Var *)NULL) && (ctxt != VAR_CMD) && (ctxt != VAR_GLOBAL) &&
            (vlen == 2) && (str[1] == 'F' || str[1] == 'D'))
        {
            /*
             * Check for bogus D and F forms of local variables since we're
             * in a local context and the name is the right length.
             */
            switch (str[0]) {
                case '@':
                case '%':
                case '*':
                case '!':
                case '>':
                case '<':
                {
                    char    vname[2];
                    char    *val;

                    /*
                     * Well, it's local -- go look for it.
                     */
                    vname[0] = str[0];
                    vname[1] = '\0';
                    v = VarFind(vname, ctxt, 0);

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

                        if (str[1] == 'D') {
                            val = VarModify(val, VarHead, (void *)NULL);
                        } else {
                            val = VarModify(val, VarTail, (void *)NULL);
                        }
                        /*
                         * Resulting string is dynamically allocated, so
                         * tell caller to free it.
                         */
                        *freePtr = TRUE;
                        *lengthPtr = tstr-start+1;
                        *tstr = endc;
                        Buf_Destroy(buf, TRUE);
                        return (val);
                    }
                    break;
                default:
                    break;
                }
            }
        }

        if (v == (Var *)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[0]) {
                    case '@':
                    case '%':
                    case '*':
                    case '!':
                        dynamic = TRUE;
                        break;
                    default:
                        break;
                }
            } else if ((vlen > 2) && (str[0] == '.') &&
                       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;
                *tstr = endc;
                if (dynamic) {
                    str = emalloc(*lengthPtr + 1);
                    strncpy(str, start, *lengthPtr);
                    str[*lengthPtr] = '\0';
                    *freePtr = TRUE;
                    Buf_Destroy(buf, TRUE);
                    return (str);
                } else {
                    Buf_Destroy(buf, TRUE);
                    return (err ? 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 = VarCreate(str, NULL, VAR_JUNK);
            }
        }
        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.
     */
    str = (char *)Buf_GetAll(v->val, (size_t *)NULL);
    if (strchr(str, '$') != (char *)NULL) {
        str = Var_Subst(NULL, str, ctxt, err);
        *freePtr = TRUE;
    }

    v->flags &= ~VAR_IN_USE;

    /*
     * 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.
     *            :S<d><pat1><d><pat2><d>[g]
     *                          Substitute <pat2> for <pat1> in the value
     *            :C<d><pat1><d><pat2><d>[g]
     *                          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).
     *            :lhs=rhs      Like :S, but the rhs goes to the end of
     *                          the invocation.
     *            :U            Converts variable to upper-case.
     *            :L            Converts variable to lower-case.
     */
    if ((str != NULL) && haveModifier) {
        /*
         * Skip initial colon while putting it back.
         */
        *tstr++ = ':';
        while (*tstr != endc) {
            char        *newStr;    /* New value to return */
            char        termc;      /* Character which terminated scan */

            DEBUGF(VAR, ("Applying :%c to \"%s\"\n", *tstr, str));
            switch (*tstr) {
                case 'N':
                case 'M':
                {
                    char    *pattern;
                    char    *cp2;
                    Boolean copy;

                    copy = FALSE;
                    for (cp = tstr + 1;
                         *cp != '\0' && *cp != ':' && *cp != endc;
                         cp++)
                    {
                        if (*cp == '\\' && (cp[1] == ':' || cp[1] == endc)) {
                            copy = TRUE;
                            cp++;
                        }
                    }
                    termc = *cp;
                    *cp = '\0';
                    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 = emalloc(cp - tstr);
                        for (cp2 = pattern, cp = tstr + 1;
                             *cp != '\0';
                             cp++, cp2++)
                        {
                            if ((*cp == '\\') &&
                                (cp[1] == ':' || cp[1] == endc)) {
                                    cp++;
                            }
                            *cp2 = *cp;
                        }
                        *cp2 = '\0';
                    } else {
                        pattern = &tstr[1];
                    }
                    if (*tstr == 'M' || *tstr == 'm') {
                        newStr = VarModify(str, VarMatch, pattern);
                    } else {
                        newStr = VarModify(str, VarNoMatch, pattern);
                    }
                    if (copy) {
                        free(pattern);
                    }
                    break;
                }
                case 'S':
                {
                    VarPattern      pattern;
                    char            del;
                    Buffer          *buf;       /* Buffer for patterns */

                    pattern.flags = 0;
                    del = 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;
                    }

                    buf = Buf_Init(0);

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

                                cp2 = Var_Parse(cp, ctxt, err, &len, &freeIt);
                                Buf_Append(buf, cp2);
                                if (freeIt) {
                                    free(cp2);
                                }
                                cp += len - 1;
                            } else {
                                /*
                                 * Unescaped $ at end of pattern => anchor
                                 * pattern at end.
                                 */
                                pattern.flags |= VAR_MATCH_END;
                            }
                        } else {
                            Buf_AddByte(buf, (Byte)*cp);
                        }
                    }

                    Buf_AddByte(buf, (Byte)'\0');

                    /*
                     * If lhs didn't end with the delimiter, complain and
                     * exit.
                     */
                    if (*cp != del) {
                        Fatal("Unclosed substitution for %s (%c missing)",
                              v->name, del);
                    }

                    /*
                     * Fetch pattern and destroy buffer, but preserve the data
                     * in it, since that's our lhs. Note that Buf_GetAll
                     * will return the actual number of bytes, which includes
                     * the null byte, so we have to decrement the length by
                     * one.
                     */
                    pattern.lhs = (char *)Buf_GetAll(buf, &pattern.leftLen);
                    pattern.leftLen--;
                    Buf_Destroy(buf, FALSE);

                    /*
                     * Now comes the replacement string. Three things need to
                     * be done here: 1) need to compress escaped delimiters and
                     * ampersands and 2) need to replace unescaped ampersands
                     * with the l.h.s. (since this isn't regexp, we can do
                     * it right here) and 3) expand any variable substitutions.
                     */
                    buf = Buf_Init(0);

                    tstr = cp + 1;
                    for (cp = tstr; *cp != '\0' && *cp != del; cp++) {
                        if ((*cp == '\\') &&
                            ((cp[1] == del) ||
                             (cp[1] == '&') ||
                             (cp[1] == '\\') ||
                             (cp[1] == '$')))
                        {
                            Buf_AddByte(buf, (Byte)cp[1]);
                            cp++;
                        } else if ((*cp == '$') && (cp[1] != del)) {
                            char    *cp2;
                            size_t len;
                            Boolean freeIt;

                            cp2 = Var_Parse(cp, ctxt, err, &len, &freeIt);
                            Buf_Append(buf, cp2);
                            cp += len - 1;
                            if (freeIt) {
                                free(cp2);
                            }
                        } else if (*cp == '&') {
                            Buf_AddBytes(buf, pattern.leftLen,
                                         (Byte *)pattern.lhs);
                        } else {
                            Buf_AddByte(buf, (Byte)*cp);
                        }
                    }

                    Buf_AddByte(buf, (Byte)'\0');

                    /*
                     * If didn't end in delimiter character, complain
                     */
                    if (*cp != del) {
                        Fatal("Unclosed substitution for %s (%c missing)",
                              v->name, del);
                    }

                    pattern.rhs = (char *)Buf_GetAll(buf, &pattern.rightLen);
                    pattern.rightLen--;
                    Buf_Destroy(buf, FALSE);

                    /*
                     * Check for global substitution. If 'g' after the final
                     * delimiter, substitution is global and is marked that
                     * way.
                     */
                    cp++;
                    if (*cp == 'g') {
                        pattern.flags |= VAR_SUB_GLOBAL;
                        cp++;
                    }

                    /*
                     * Global substitution of the empty string causes an
                     * infinite number of matches, unless anchored by '^'
                     * (start of string) or '$' (end of string). Catch the
                     * infinite substitution here.
                     * Note that flags can only contain the 3 bits we're
                     * interested in so we don't have to mask unrelated
                     * bits. We can test for equality.
                     */
                    if (!pattern.leftLen && pattern.flags == VAR_SUB_GLOBAL)
                        Fatal("Global substitution of the empty string");

                    termc = *cp;
                    newStr = VarModify(str, VarSubstitute, &pattern);
                    /*
                     * Free the two strings.
                     */
                    free(pattern.lhs);
                    free(pattern.rhs);
                    break;
                }
                case 'C':
                {
                    VarREPattern    pattern;
                    char           *re;
                    int             error;

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

                    cp = tstr;

                    if ((re = VarGetPattern(ctxt, err, &cp, delim, NULL,
                        NULL, NULL)) == NULL) {
                        /* was: goto cleanup */
                        *lengthPtr = cp - start + 1;
                        if (*freePtr)
                            free(str);
                        if (delim != '\0')
                            Fatal("Unclosed substitution for %s (%c missing)",
                                  v->name, delim);
                        return (var_Error);
                    }

                    if ((pattern.replace = VarGetPattern(ctxt, err, &cp,
                        delim, NULL, NULL, NULL)) == NULL){
                        free(re);

                        /* was: goto cleanup */
                        *lengthPtr = cp - start + 1;
                        if (*freePtr)
                            free(str);
                        if (delim != '\0')
                            Fatal("Unclosed substitution for %s (%c missing)",
                                  v->name, delim);
                        return (var_Error);
                    }

                    for (;; cp++) {
                        switch (*cp) {
                        case 'g':
                            pattern.flags |= VAR_SUB_GLOBAL;
                            continue;
                        case '1':
                            pattern.flags |= VAR_SUB_ONE;
                            continue;
                        default:
                            break;
                        }
                        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);
                        return (var_Error);
                    }

                    pattern.nsub = pattern.re.re_nsub + 1;
                    if (pattern.nsub < 1)
                        pattern.nsub = 1;
                    if (pattern.nsub > 10)
                        pattern.nsub = 10;
                    pattern.matches = emalloc(pattern.nsub *
                                              sizeof(regmatch_t));
                    newStr = VarModify(str, VarRESubstitute, &pattern);
                    regfree(&pattern.re);
                    free(pattern.replace);
                    free(pattern.matches);
                    break;
                }
                case 'L':
                    if (tstr[1] == endc || tstr[1] == ':') {
                        Buffer *buf;
                        buf = Buf_Init(MAKE_BSIZE);
                        for (cp = str; *cp ; cp++)
                            Buf_AddByte(buf, (Byte)tolower(*cp));

                        Buf_AddByte(buf, (Byte)'\0');
                        newStr = (char *)Buf_GetAll(buf, (size_t *)NULL);
                        Buf_Destroy(buf, FALSE);

                        cp = tstr + 1;
                        termc = *cp;
                        break;
                    }
                    /* FALLTHROUGH */
                case 'O':
                    if (tstr[1] == endc || tstr[1] == ':') {
                        newStr = VarSortWords(str, SortIncreasing);
                        cp = tstr + 1;
                        termc = *cp;
                        break;
                    }
                    /* FALLTHROUGH */
                case 'Q':
                    if (tstr[1] == endc || tstr[1] == ':') {
                        newStr = Var_Quote(str);
                        cp = tstr + 1;
                        termc = *cp;
                        break;
                    }
                    /*FALLTHRU*/
                case 'T':
                    if (tstr[1] == endc || tstr[1] == ':') {
                        newStr = VarModify(str, VarTail, (void *)NULL);
                        cp = tstr + 1;
                        termc = *cp;
                        break;
                    }
                    /*FALLTHRU*/
                case 'U':
                    if (tstr[1] == endc || tstr[1] == ':') {
                        Buffer *buf;
                        buf = Buf_Init(MAKE_BSIZE);
                        for (cp = str; *cp ; cp++)
                            Buf_AddByte(buf, (Byte)toupper(*cp));

                        Buf_AddByte(buf, (Byte)'\0');
                        newStr = (char *)Buf_GetAll(buf, (size_t *)NULL);
                        Buf_Destroy(buf, FALSE);

                        cp = tstr + 1;
                        termc = *cp;
                        break;
                    }
                    /* FALLTHROUGH */
                case 'H':
                    if (tstr[1] == endc || tstr[1] == ':') {
                        newStr = VarModify(str, VarHead, (void *)NULL);
                        cp = tstr + 1;
                        termc = *cp;
                        break;
                    }
                    /*FALLTHRU*/
                case 'E':
                    if (tstr[1] == endc || tstr[1] == ':') {
                        newStr = VarModify(str, VarSuffix, (void *)NULL);
                        cp = tstr + 1;
                        termc = *cp;
                        break;
                    }
                    /*FALLTHRU*/
                case 'R':
                    if (tstr[1] == endc || tstr[1] == ':') {
                        newStr = VarModify(str, VarRoot, (void *)NULL);
                        cp = tstr + 1;
                        termc = *cp;
                        break;
                    }
                    /*FALLTHRU*/
#ifdef SUNSHCMD
                case 's':
                    if (tstr[1] == 'h' && (tstr[2] == endc || tstr[2] == ':')) {
                        const char *error;
                        {
                            Buffer *buf = Cmd_Exec(str, &error);
                            newStr = Buf_GetAll(buf, NULL);
                            Buf_Destroy(buf, FALSE);
                        }
                        if (error)
                            Error(error, str);
                        cp = tstr + 2;
                        termc = *cp;
                        break;
                    }
                    /*FALLTHRU*/
#endif
                default:
                {
#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.
                         */
                        cp = tstr;

                        delim = '=';
                        if ((pattern.lhs = VarGetPattern(ctxt,
                            err, &cp, delim, &pattern.flags, &pattern.leftLen,
                            NULL)) == NULL) {
                                /* was: goto cleanup */
                                *lengthPtr = cp - start + 1;
                                if (*freePtr)
                                    free(str);
                                if (delim != '\0')
                                    Fatal("Unclosed substitution for %s (%c missing)",
                                          v->name, delim);
                                return (var_Error);
                        }

                        delim = endc;
                        if ((pattern.rhs = VarGetPattern(ctxt,
                            err, &cp, delim, NULL, &pattern.rightLen,
                            &pattern)) == NULL) {
                                /* was: goto cleanup */
                                *lengthPtr = cp - start + 1;
                                if (*freePtr)
                                    free(str);
                                if (delim != '\0')
                                    Fatal("Unclosed substitution for %s (%c missing)",
                                          v->name, delim);
                                return (var_Error);
                        }

                        /*
                         * SYSV modifications happen through the whole
                         * string. Note the pattern is anchored at the end.
                         */
                        termc = *--cp;
                        delim = '\0';
                        newStr = VarModify(str, VarSYSVMatch, &pattern);

                        free(pattern.lhs);
                        free(pattern.rhs);

                        termc = endc;
                    } else
#endif
                    {
                        Error("Unknown modifier '%c'\n", *tstr);
                        for (cp = tstr+1;
                             *cp != ':' && *cp != endc && *cp != '\0';
                             cp++)
                                 continue;
                        termc = *cp;
                        newStr = var_Error;
                    }
                }
            }
            DEBUGF(VAR, ("Result is \"%s\"\n", newStr));

            if (*freePtr) {
                free(str);
            }
            str = newStr;
            if (str != var_Error) {
                *freePtr = TRUE;
            } else {
                *freePtr = FALSE;
            }
            if (termc == '\0') {
                Error("Unclosed variable specification for %s", v->name);
            } else if (termc == ':') {
                *cp++ = termc;
            } else {
                *cp = termc;
            }
            tstr = cp;
        }
        *lengthPtr = tstr - start + 1;
    } else {
        *lengthPtr = tstr - start + 1;
        *tstr = endc;
    }

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

        if (str != (char *)Buf_GetAll(v->val, (size_t *)NULL)) {
            destroy = TRUE;
        } else {
            /*
             * Returning the value unmodified, so tell the caller to free
             * the thing.
             */
            *freePtr = TRUE;
        }
        VarDestroy(v, destroy);
    } else if (v->flags & VAR_JUNK) {
        /*
         * Perform any free'ing needed and set *freePtr to FALSE so the caller
         * doesn't try to free a static pointer.
         */
        if (*freePtr) {
            free(str);
        }
        *freePtr = FALSE;
        VarDestroy(v, TRUE);
        if (dynamic) {
            str = emalloc(*lengthPtr + 1);
            strncpy(str, start, *lengthPtr);
            str[*lengthPtr] = '\0';
            *freePtr = TRUE;
        } else {
            str = err ? var_Error : varNoError;
        }
    }
    return (str);
}

/*-
 *-----------------------------------------------------------------------
 * 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.
 *
 * 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 */
    size_t        length;           /* Length of the variable invocation */
    Boolean       doFree;           /* Set true if val should be freed */
    char        *result;
    static Boolean errorReported;/* Set true if an error has already
                                     * been reported to prevent a plethora
                                     * of messages when recursing */

    buf = Buf_Init(MAKE_BSIZE);
    errorReported = FALSE;

    while (*str) {
        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, (Byte)*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_AppendRange(buf, cp, str);
        } else {
            if (var != NULL) {
                int expand;
                for (;;) {
                    if (str[1] != '(' && str[1] != '{') {
                        if (str[1] != *var || var[1] != '\0') {
                            Buf_AddBytes(buf, 2, (const Byte *)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 != ')' && *p != '}'; 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_AppendRange(buf, str, p);
                            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_AppendRange(buf, str, p);
                            str = p;
                            expand = FALSE;
                        }
                        else
                            expand = TRUE;
                        break;
                    }
                }
                if (!expand)
                    continue;
            }

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

            /*
             * 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, (Byte)*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.
                 */
                Buf_Append(buf, val);
                if (doFree) {
                    free(val);
                }
            }
        }
    }

    Buf_AddByte(buf, '\0');
    result = (char *)Buf_GetAll(buf, (size_t *)NULL);
    Buf_Destroy(buf, FALSE);
    return (result);
}

/*-
 *-----------------------------------------------------------------------
 * Var_GetTail --
 *      Return the tail from each of a list of words. Used to set the
 *      System V local variables.
 *
 * Results:
 *      The resulting string.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
char *
Var_GetTail(char *file)
{
    return (VarModify(file, VarTail, (void *)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.
 *
 * Results:
 *      The leading components.
 *
 * Side Effects:
 *      None.
 *
 *-----------------------------------------------------------------------
 */
char *
Var_GetHead(char *file)
{

    return (VarModify(file, VarHead, (void *)NULL));
}

/*-
 *-----------------------------------------------------------------------
 * 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");
}

/****************** PRINT DEBUGGING INFO *****************/
static int
VarPrintVar(void *vp, void *dummy __unused)
{
    Var    *v = (Var *) vp;

    printf("%-16s = %s\n", v->name, (char *)Buf_GetAll(v->val, (size_t *)NULL));
    return (0);
}

/*-
 *-----------------------------------------------------------------------
 * Var_Dump --
 *      print all variables in a context
 *-----------------------------------------------------------------------
 */
void
Var_Dump(GNode *ctxt)
{
    Lst_ForEach(&ctxt->context, VarPrintVar, (void *)NULL);
}