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/*      $NetBSD: dir.c,v 1.69 2017/01/31 06:54:23 sjg Exp $     */

/*
 * Copyright (c) 1988, 1989, 1990 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) 1988, 1989 by Adam de Boor
 * 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: dir.c,v 1.69 2017/01/31 06:54:23 sjg Exp $";
#else
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)dir.c       8.2 (Berkeley) 1/2/94";
#else
__RCSID("$NetBSD: dir.c,v 1.69 2017/01/31 06:54:23 sjg Exp $");
#endif
#endif /* not lint */
#endif

/*-
 * dir.c --
 *      Directory searching using wildcards and/or normal names...
 *      Used both for source wildcarding in the Makefile and for finding
 *      implicit sources.
 *
 * The interface for this module is:
 *      Dir_Init            Initialize the module.
 *
 *      Dir_InitCur         Set the cur Path.
 *
 *      Dir_InitDot         Set the dot Path.
 *
 *      Dir_End             Cleanup the module.
 *
 *      Dir_SetPATH         Set ${.PATH} to reflect state of dirSearchPath.
 *
 *      Dir_HasWildcards    Returns TRUE if the name given it needs to
 *                          be wildcard-expanded.
 *
 *      Dir_Expand          Given a pattern and a path, return a Lst of names
 *                          which match the pattern on the search path.
 *
 *      Dir_FindFile        Searches for a file on a given search path.
 *                          If it exists, the entire path is returned.
 *                          Otherwise NULL is returned.
 *
 *      Dir_FindHereOrAbove Search for a path in the current directory and
 *                          then all the directories above it in turn until
 *                          the path is found or we reach the root ("/").
 * 
 *      Dir_MTime           Return the modification time of a node. The file
 *                          is searched for along the default search path.
 *                          The path and mtime fields of the node are filled
 *                          in.
 *
 *      Dir_AddDir          Add a directory to a search path.
 *
 *      Dir_MakeFlags       Given a search path and a command flag, create
 *                          a string with each of the directories in the path
 *                          preceded by the command flag and all of them
 *                          separated by a space.
 *
 *      Dir_Destroy         Destroy an element of a search path. Frees up all
 *                          things that can be freed for the element as long
 *                          as the element is no longer referenced by any other
 *                          search path.
 *      Dir_ClearPath       Resets a search path to the empty list.
 *
 * For debugging:
 *      Dir_PrintDirectories    Print stats about the directory cache.
 */

#include <sys/types.h>
#include <sys/stat.h>

#include <dirent.h>
#include <errno.h>
#include <stdio.h>

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

/*
 *      A search path consists of a Lst of Path structures. A Path structure
 *      has in it the name of the directory and a hash table of all the files
 *      in the directory. This is used to cut down on the number of system
 *      calls necessary to find implicit dependents and their like. Since
 *      these searches are made before any actions are taken, we need not
 *      worry about the directory changing due to creation commands. If this
 *      hampers the style of some makefiles, they must be changed.
 *
 *      A list of all previously-read directories is kept in the
 *      openDirectories Lst. This list is checked first before a directory
 *      is opened.
 *
 *      The need for the caching of whole directories is brought about by
 *      the multi-level transformation code in suff.c, which tends to search
 *      for far more files than regular make does. In the initial
 *      implementation, the amount of time spent performing "stat" calls was
 *      truly astronomical. The problem with hashing at the start is,
 *      of course, that pmake doesn't then detect changes to these directories
 *      during the course of the make. Three possibilities suggest themselves:
 *
 *          1) just use stat to test for a file's existence. As mentioned
 *             above, this is very inefficient due to the number of checks
 *             engendered by the multi-level transformation code.
 *          2) use readdir() and company to search the directories, keeping
 *             them open between checks. I have tried this and while it
 *             didn't slow down the process too much, it could severely
 *             affect the amount of parallelism available as each directory
 *             open would take another file descriptor out of play for
 *             handling I/O for another job. Given that it is only recently
 *             that UNIX OS's have taken to allowing more than 20 or 32
 *             file descriptors for a process, this doesn't seem acceptable
 *             to me.
 *          3) record the mtime of the directory in the Path structure and
 *             verify the directory hasn't changed since the contents were
 *             hashed. This will catch the creation or deletion of files,
 *             but not the updating of files. However, since it is the
 *             creation and deletion that is the problem, this could be
 *             a good thing to do. Unfortunately, if the directory (say ".")
 *             were fairly large and changed fairly frequently, the constant
 *             rehashing could seriously degrade performance. It might be
 *             good in such cases to keep track of the number of rehashes
 *             and if the number goes over a (small) limit, resort to using
 *             stat in its place.
 *
 *      An additional thing to consider is that pmake is used primarily
 *      to create C programs and until recently pcc-based compilers refused
 *      to allow you to specify where the resulting object file should be
 *      placed. This forced all objects to be created in the current
 *      directory. This isn't meant as a full excuse, just an explanation of
 *      some of the reasons for the caching used here.
 *
 *      One more note: the location of a target's file is only performed
 *      on the downward traversal of the graph and then only for terminal
 *      nodes in the graph. This could be construed as wrong in some cases,
 *      but prevents inadvertent modification of files when the "installed"
 *      directory for a file is provided in the search path.
 *
 *      Another data structure maintained by this module is an mtime
 *      cache used when the searching of cached directories fails to find
 *      a file. In the past, Dir_FindFile would simply perform an access()
 *      call in such a case to determine if the file could be found using
 *      just the name given. When this hit, however, all that was gained
 *      was the knowledge that the file existed. Given that an access() is
 *      essentially a stat() without the copyout() call, and that the same
 *      filesystem overhead would have to be incurred in Dir_MTime, it made
 *      sense to replace the access() with a stat() and record the mtime
 *      in a cache for when Dir_MTime was actually called.
 */

Lst          dirSearchPath;     /* main search path */

static Lst   openDirectories;   /* the list of all open directories */

/*
 * Variables for gathering statistics on the efficiency of the hashing
 * mechanism.
 */
static int    hits,           /* Found in directory cache */
              misses,         /* Sad, but not evil misses */
              nearmisses,     /* Found under search path */
              bigmisses;      /* Sought by itself */

static Path       *dot;     /* contents of current directory */
static Path       *cur;     /* contents of current directory, if not dot */
static Path       *dotLast; /* a fake path entry indicating we need to
                             * look for . last */
static Hash_Table mtimes;   /* Results of doing a last-resort stat in
                             * Dir_FindFile -- if we have to go to the
                             * system to find the file, we might as well
                             * have its mtime on record. XXX: If this is done
                             * way early, there's a chance other rules will
                             * have already updated the file, in which case
                             * we'll update it again. Generally, there won't
                             * be two rules to update a single file, so this
                             * should be ok, but... */

static Hash_Table lmtimes;  /* same as mtimes but for lstat */

static int DirFindName(const void *, const void *);
static int DirMatchFiles(const char *, Path *, Lst);
static void DirExpandCurly(const char *, const char *, Lst, Lst);
static void DirExpandInt(const char *, Lst, Lst);
static int DirPrintWord(void *, void *);
static int DirPrintDir(void *, void *);
static char *DirLookup(Path *, const char *, const char *, Boolean);
static char *DirLookupSubdir(Path *, const char *);
static char *DirFindDot(Boolean, const char *, const char *);
static char *DirLookupAbs(Path *, const char *, const char *);


/*
 * We use stat(2) a lot, cache the results
 * mtime and mode are all we care about.
 */
struct cache_st {
    time_t mtime;
    mode_t  mode;
};

/* minimize changes below */
static time_t
Hash_GetTimeValue(Hash_Entry *entry)
{
    struct cache_st *cst;

    cst = entry->clientPtr;
    return cst->mtime;
}

#define CST_LSTAT 1
#define CST_UPDATE 2

static int
cached_stats(Hash_Table *htp, const char *pathname, struct stat *st, int flags)
{
    Hash_Entry *entry;
    struct cache_st *cst;
    int rc;

    if (!pathname || !pathname[0])
        return -1;

    entry = Hash_FindEntry(htp, pathname);

    if (entry && (flags & CST_UPDATE) == 0) {
        cst = entry->clientPtr;

        memset(st, 0, sizeof(*st));
        st->st_mtime = cst->mtime;
        st->st_mode = cst->mode;
        return 0;
    }

    rc = (flags & CST_LSTAT) ? lstat(pathname, st) : stat(pathname, st);
    if (rc == -1)
        return -1;

    if (st->st_mtime == 0)
        st->st_mtime = 1;      /* avoid confusion with missing file */

    if (!entry)
        entry = Hash_CreateEntry(htp, pathname, NULL);
    if (!entry->clientPtr)
        entry->clientPtr = bmake_malloc(sizeof(*cst));
    cst = entry->clientPtr;
    cst->mtime = st->st_mtime;
    cst->mode = st->st_mode;

    return 0;
}

int
cached_stat(const char *pathname, void *st)
{
    return cached_stats(&mtimes, pathname, st, 0);
}

int
cached_lstat(const char *pathname, void *st)
{
    return cached_stats(&lmtimes, pathname, st, CST_LSTAT);
}

/*-
 *-----------------------------------------------------------------------
 * Dir_Init --
 *      initialize things for this module
 *
 * Results:
 *      none
 *
 * Side Effects:
 *      some directories may be opened.
 *-----------------------------------------------------------------------
 */
void
Dir_Init(const char *cdname)
{
    if (!cdname) {
        dirSearchPath = Lst_Init(FALSE);
        openDirectories = Lst_Init(FALSE);
        Hash_InitTable(&mtimes, 0);
        Hash_InitTable(&lmtimes, 0);
        return;
    }
    Dir_InitCur(cdname);

    dotLast = bmake_malloc(sizeof(Path));
    dotLast->refCount = 1;
    dotLast->hits = 0;
    dotLast->name = bmake_strdup(".DOTLAST");
    Hash_InitTable(&dotLast->files, -1);
}

/*
 * Called by Dir_Init() and whenever .CURDIR is assigned to.
 */
void
Dir_InitCur(const char *cdname)
{
    Path *p;
    
    if (cdname != NULL) {
        /*
         * Our build directory is not the same as our source directory.
         * Keep this one around too.
         */
        if ((p = Dir_AddDir(NULL, cdname))) {
            p->refCount += 1;
            if (cur && cur != p) {
                /*
                 * We've been here before, cleanup.
                 */
                cur->refCount -= 1;
                Dir_Destroy(cur);
            }
            cur = p;
        }
    }
}

/*-
 *-----------------------------------------------------------------------
 * Dir_InitDot --
 *      (re)initialize "dot" (current/object directory) path hash
 *
 * Results:
 *      none
 *
 * Side Effects:
 *      some directories may be opened.
 *-----------------------------------------------------------------------
 */
void
Dir_InitDot(void)
{
    if (dot != NULL) {
        LstNode ln;

        /* Remove old entry from openDirectories, but do not destroy. */
        ln = Lst_Member(openDirectories, dot);
        (void)Lst_Remove(openDirectories, ln);
    }

    dot = Dir_AddDir(NULL, ".");

    if (dot == NULL) {
        Error("Cannot open `.' (%s)", strerror(errno));
        exit(1);
    }

    /*
     * We always need to have dot around, so we increment its reference count
     * to make sure it's not destroyed.
     */
    dot->refCount += 1;
    Dir_SetPATH();                      /* initialize */
}

/*-
 *-----------------------------------------------------------------------
 * Dir_End --
 *      cleanup things for this module
 *
 * Results:
 *      none
 *
 * Side Effects:
 *      none
 *-----------------------------------------------------------------------
 */
void
Dir_End(void)
{
#ifdef CLEANUP
    if (cur) {
        cur->refCount -= 1;
        Dir_Destroy(cur);
    }
    dot->refCount -= 1;
    dotLast->refCount -= 1;
    Dir_Destroy(dotLast);
    Dir_Destroy(dot);
    Dir_ClearPath(dirSearchPath);
    Lst_Destroy(dirSearchPath, NULL);
    Dir_ClearPath(openDirectories);
    Lst_Destroy(openDirectories, NULL);
    Hash_DeleteTable(&mtimes);
#endif
}

/*
 * We want ${.PATH} to indicate the order in which we will actually
 * search, so we rebuild it after any .PATH: target.
 * This is the simplest way to deal with the effect of .DOTLAST.
 */
void
Dir_SetPATH(void)
{
    LstNode       ln;           /* a list element */
    Path *p;
    Boolean       hasLastDot = FALSE;   /* true we should search dot last */

    Var_Delete(".PATH", VAR_GLOBAL);
    
    if (Lst_Open(dirSearchPath) == SUCCESS) {
        if ((ln = Lst_First(dirSearchPath)) != NULL) {
            p = (Path *)Lst_Datum(ln);
            if (p == dotLast) {
                hasLastDot = TRUE;
                Var_Append(".PATH", dotLast->name, VAR_GLOBAL);
            }
        }

        if (!hasLastDot) {
            if (dot)
                Var_Append(".PATH", dot->name, VAR_GLOBAL);
            if (cur)
                Var_Append(".PATH", cur->name, VAR_GLOBAL);
        }

        while ((ln = Lst_Next(dirSearchPath)) != NULL) {
            p = (Path *)Lst_Datum(ln);
            if (p == dotLast)
                continue;
            if (p == dot && hasLastDot)
                continue;
            Var_Append(".PATH", p->name, VAR_GLOBAL);
        }

        if (hasLastDot) {
            if (dot)
                Var_Append(".PATH", dot->name, VAR_GLOBAL);
            if (cur)
                Var_Append(".PATH", cur->name, VAR_GLOBAL);
        }
        Lst_Close(dirSearchPath);
    }
}

/*-
 *-----------------------------------------------------------------------
 * DirFindName --
 *      See if the Path structure describes the same directory as the
 *      given one by comparing their names. Called from Dir_AddDir via
 *      Lst_Find when searching the list of open directories.
 *
 * Input:
 *      p               Current name
 *      dname           Desired name
 *
 * Results:
 *      0 if it is the same. Non-zero otherwise
 *
 * Side Effects:
 *      None
 *-----------------------------------------------------------------------
 */
static int
DirFindName(const void *p, const void *dname)
{
    return (strcmp(((const Path *)p)->name, dname));
}

/*-
 *-----------------------------------------------------------------------
 * Dir_HasWildcards  --
 *      see if the given name has any wildcard characters in it
 *      be careful not to expand unmatching brackets or braces.
 *      XXX: This code is not 100% correct. ([^]] fails etc.) 
 *      I really don't think that make(1) should be expanding
 *      patterns, because then you have to set a mechanism for
 *      escaping the expansion!
 *
 * Input:
 *      name            name to check
 *
 * Results:
 *      returns TRUE if the word should be expanded, FALSE otherwise
 *
 * Side Effects:
 *      none
 *-----------------------------------------------------------------------
 */
Boolean
Dir_HasWildcards(char *name)
{
    char *cp;
    int wild = 0, brace = 0, bracket = 0;

    for (cp = name; *cp; cp++) {
        switch(*cp) {
        case '{':
                brace++;
                wild = 1;
                break;
        case '}':
                brace--;
                break;
        case '[':
                bracket++;
                wild = 1;
                break;
        case ']':
                bracket--;
                break;
        case '?':
        case '*':
                wild = 1;
                break;
        default:
                break;
        }
    }
    return wild && bracket == 0 && brace == 0;
}

/*-
 *-----------------------------------------------------------------------
 * DirMatchFiles --
 *      Given a pattern and a Path structure, see if any files
 *      match the pattern and add their names to the 'expansions' list if
 *      any do. This is incomplete -- it doesn't take care of patterns like
 *      src / *src / *.c properly (just *.c on any of the directories), but it
 *      will do for now.
 *
 * Input:
 *      pattern         Pattern to look for
 *      p               Directory to search
 *      expansion       Place to store the results
 *
 * Results:
 *      Always returns 0
 *
 * Side Effects:
 *      File names are added to the expansions lst. The directory will be
 *      fully hashed when this is done.
 *-----------------------------------------------------------------------
 */
static int
DirMatchFiles(const char *pattern, Path *p, Lst expansions)
{
    Hash_Search   search;       /* Index into the directory's table */
    Hash_Entry    *entry;       /* Current entry in the table */
    Boolean       isDot;        /* TRUE if the directory being searched is . */

    isDot = (*p->name == '.' && p->name[1] == '\0');

    for (entry = Hash_EnumFirst(&p->files, &search);
         entry != NULL;
         entry = Hash_EnumNext(&search))
    {
        /*
         * See if the file matches the given pattern. Note we follow the UNIX
         * convention that dot files will only be found if the pattern
         * begins with a dot (note also that as a side effect of the hashing
         * scheme, .* won't match . or .. since they aren't hashed).
         */
        if (Str_Match(entry->name, pattern) &&
            ((entry->name[0] != '.') ||
             (pattern[0] == '.')))
        {
            (void)Lst_AtEnd(expansions,
                            (isDot ? bmake_strdup(entry->name) :
                             str_concat(p->name, entry->name,
                                        STR_ADDSLASH)));
        }
    }
    return (0);
}

/*-
 *-----------------------------------------------------------------------
 * DirExpandCurly --
 *      Expand curly braces like the C shell. Does this recursively.
 *      Note the special case: if after the piece of the curly brace is
 *      done there are no wildcard characters in the result, the result is
 *      placed on the list WITHOUT CHECKING FOR ITS EXISTENCE.
 *
 * Input:
 *      word            Entire word to expand
 *      brace           First curly brace in it
 *      path            Search path to use
 *      expansions      Place to store the expansions
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      The given list is filled with the expansions...
 *
 *-----------------------------------------------------------------------
 */
static void
DirExpandCurly(const char *word, const char *brace, Lst path, Lst expansions)
{
    const char   *end;          /* Character after the closing brace */
    const char   *cp;           /* Current position in brace clause */
    const char   *start;        /* Start of current piece of brace clause */
    int           bracelevel;   /* Number of braces we've seen. If we see a
                                 * right brace when this is 0, we've hit the
                                 * end of the clause. */
    char         *file;         /* Current expansion */
    int           otherLen;     /* The length of the other pieces of the
                                 * expansion (chars before and after the
                                 * clause in 'word') */
    char         *cp2;          /* Pointer for checking for wildcards in
                                 * expansion before calling Dir_Expand */

    start = brace+1;

    /*
     * Find the end of the brace clause first, being wary of nested brace
     * clauses.
     */
    for (end = start, bracelevel = 0; *end != '\0'; end++) {
        if (*end == '{') {
            bracelevel++;
        } else if ((*end == '}') && (bracelevel-- == 0)) {
            break;
        }
    }
    if (*end == '\0') {
        Error("Unterminated {} clause \"%s\"", start);
        return;
    } else {
        end++;
    }
    otherLen = brace - word + strlen(end);

    for (cp = start; cp < end; cp++) {
        /*
         * Find the end of this piece of the clause.
         */
        bracelevel = 0;
        while (*cp != ',') {
            if (*cp == '{') {
                bracelevel++;
            } else if ((*cp == '}') && (bracelevel-- <= 0)) {
                break;
            }
            cp++;
        }
        /*
         * Allocate room for the combination and install the three pieces.
         */
        file = bmake_malloc(otherLen + cp - start + 1);
        if (brace != word) {
            strncpy(file, word, brace-word);
        }
        if (cp != start) {
            strncpy(&file[brace-word], start, cp-start);
        }
        strcpy(&file[(brace-word)+(cp-start)], end);

        /*
         * See if the result has any wildcards in it. If we find one, call
         * Dir_Expand right away, telling it to place the result on our list
         * of expansions.
         */
        for (cp2 = file; *cp2 != '\0'; cp2++) {
            switch(*cp2) {
            case '*':
            case '?':
            case '{':
            case '[':
                Dir_Expand(file, path, expansions);
                goto next;
            }
        }
        if (*cp2 == '\0') {
            /*
             * Hit the end w/o finding any wildcards, so stick the expansion
             * on the end of the list.
             */
            (void)Lst_AtEnd(expansions, file);
        } else {
        next:
            free(file);
        }
        start = cp+1;
    }
}


/*-
 *-----------------------------------------------------------------------
 * DirExpandInt --
 *      Internal expand routine. Passes through the directories in the
 *      path one by one, calling DirMatchFiles for each. NOTE: This still
 *      doesn't handle patterns in directories...
 *
 * Input:
 *      word            Word to expand
 *      path            Path on which to look
 *      expansions      Place to store the result
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      Things are added to the expansions list.
 *
 *-----------------------------------------------------------------------
 */
static void
DirExpandInt(const char *word, Lst path, Lst expansions)
{
    LstNode       ln;           /* Current node */
    Path          *p;           /* Directory in the node */

    if (Lst_Open(path) == SUCCESS) {
        while ((ln = Lst_Next(path)) != NULL) {
            p = (Path *)Lst_Datum(ln);
            DirMatchFiles(word, p, expansions);
        }
        Lst_Close(path);
    }
}

/*-
 *-----------------------------------------------------------------------
 * DirPrintWord --
 *      Print a word in the list of expansions. Callback for Dir_Expand
 *      when DEBUG(DIR), via Lst_ForEach.
 *
 * Results:
 *      === 0
 *
 * Side Effects:
 *      The passed word is printed, followed by a space.
 *
 *-----------------------------------------------------------------------
 */
static int
DirPrintWord(void *word, void *dummy)
{
    fprintf(debug_file, "%s ", (char *)word);

    return(dummy ? 0 : 0);
}

/*-
 *-----------------------------------------------------------------------
 * Dir_Expand  --
 *      Expand the given word into a list of words by globbing it looking
 *      in the directories on the given search path.
 *
 * Input:
 *      word            the word to expand
 *      path            the list of directories in which to find the
 *                      resulting files
 *      expansions      the list on which to place the results
 *
 * Results:
 *      A list of words consisting of the files which exist along the search
 *      path matching the given pattern.
 *
 * Side Effects:
 *      Directories may be opened. Who knows?
 *-----------------------------------------------------------------------
 */
void
Dir_Expand(const char *word, Lst path, Lst expansions)
{
    const char            *cp;

    if (DEBUG(DIR)) {
        fprintf(debug_file, "Expanding \"%s\"... ", word);
    }

    cp = strchr(word, '{');
    if (cp) {
        DirExpandCurly(word, cp, path, expansions);
    } else {
        cp = strchr(word, '/');
        if (cp) {
            /*
             * The thing has a directory component -- find the first wildcard
             * in the string.
             */
            for (cp = word; *cp; cp++) {
                if (*cp == '?' || *cp == '[' || *cp == '*' || *cp == '{') {
                    break;
                }
            }
            if (*cp == '{') {
                /*
                 * This one will be fun.
                 */
                DirExpandCurly(word, cp, path, expansions);
                return;
            } else if (*cp != '\0') {
                /*
                 * Back up to the start of the component
                 */
                char  *dirpath;

                while (cp > word && *cp != '/') {
                    cp--;
                }
                if (cp != word) {
                    char sc;
                    /*
                     * If the glob isn't in the first component, try and find
                     * all the components up to the one with a wildcard.
                     */
                    sc = cp[1];
                    ((char *)UNCONST(cp))[1] = '\0';
                    dirpath = Dir_FindFile(word, path);
                    ((char *)UNCONST(cp))[1] = sc;
                    /*
                     * dirpath is null if can't find the leading component
                     * XXX: Dir_FindFile won't find internal components.
                     * i.e. if the path contains ../Etc/Object and we're
                     * looking for Etc, it won't be found. Ah well.
                     * Probably not important.
                     */
                    if (dirpath != NULL) {
                        char *dp = &dirpath[strlen(dirpath) - 1];
                        if (*dp == '/')
                            *dp = '\0';
                        path = Lst_Init(FALSE);
                        (void)Dir_AddDir(path, dirpath);
                        DirExpandInt(cp+1, path, expansions);
                        Lst_Destroy(path, NULL);
                    }
                } else {
                    /*
                     * Start the search from the local directory
                     */
                    DirExpandInt(word, path, expansions);
                }
            } else {
                /*
                 * Return the file -- this should never happen.
                 */
                DirExpandInt(word, path, expansions);
            }
        } else {
            /*
             * First the files in dot
             */
            DirMatchFiles(word, dot, expansions);

            /*
             * Then the files in every other directory on the path.
             */
            DirExpandInt(word, path, expansions);
        }
    }
    if (DEBUG(DIR)) {
        Lst_ForEach(expansions, DirPrintWord, NULL);
        fprintf(debug_file, "\n");
    }
}

/*-
 *-----------------------------------------------------------------------
 * DirLookup  --
 *      Find if the file with the given name exists in the given path.
 *
 * Results:
 *      The path to the file or NULL. This path is guaranteed to be in a
 *      different part of memory than name and so may be safely free'd.
 *
 * Side Effects:
 *      None.
 *-----------------------------------------------------------------------
 */
static char *
DirLookup(Path *p, const char *name MAKE_ATTR_UNUSED, const char *cp, 
          Boolean hasSlash MAKE_ATTR_UNUSED)
{
    char *file;         /* the current filename to check */

    if (DEBUG(DIR)) {
        fprintf(debug_file, "   %s ...\n", p->name);
    }

    if (Hash_FindEntry(&p->files, cp) == NULL)
        return NULL;

    file = str_concat(p->name, cp, STR_ADDSLASH);
    if (DEBUG(DIR)) {
        fprintf(debug_file, "   returning %s\n", file);
    }
    p->hits += 1;
    hits += 1;
    return file;
}


/*-
 *-----------------------------------------------------------------------
 * DirLookupSubdir  --
 *      Find if the file with the given name exists in the given path.
 *
 * Results:
 *      The path to the file or NULL. This path is guaranteed to be in a
 *      different part of memory than name and so may be safely free'd.
 *
 * Side Effects:
 *      If the file is found, it is added in the modification times hash
 *      table.
 *-----------------------------------------------------------------------
 */
static char *
DirLookupSubdir(Path *p, const char *name)
{
    struct stat   stb;          /* Buffer for stat, if necessary */
    char         *file;         /* the current filename to check */

    if (p != dot) {
        file = str_concat(p->name, name, STR_ADDSLASH);
    } else {
        /*
         * Checking in dot -- DON'T put a leading ./ on the thing.
         */
        file = bmake_strdup(name);
    }

    if (DEBUG(DIR)) {
        fprintf(debug_file, "checking %s ...\n", file);
    }

    if (cached_stat(file, &stb) == 0) {
        /*
         * Save the modification time so if it's needed, we don't have
         * to fetch it again.
         */
        if (DEBUG(DIR)) {
            fprintf(debug_file, "   Caching %s for %s\n", Targ_FmtTime(stb.st_mtime),
                    file);
        }
        nearmisses += 1;
        return (file);
    }
    free(file);
    return NULL;
}

/*-
 *-----------------------------------------------------------------------
 * DirLookupAbs  --
 *      Find if the file with the given name exists in the given path.
 *
 * Results:
 *      The path to the file, the empty string or NULL. If the file is
 *      the empty string, the search should be terminated.
 *      This path is guaranteed to be in a different part of memory
 *      than name and so may be safely free'd.
 *
 * Side Effects:
 *      None.
 *-----------------------------------------------------------------------
 */
static char *
DirLookupAbs(Path *p, const char *name, const char *cp)
{
        char *p1;               /* pointer into p->name */
        const char *p2;         /* pointer into name */

        if (DEBUG(DIR)) {
                fprintf(debug_file, "   %s ...\n", p->name);
        }

        /*
         * If the file has a leading path component and that component
         * exactly matches the entire name of the current search
         * directory, we can attempt another cache lookup. And if we don't
         * have a hit, we can safely assume the file does not exist at all.
         */
        for (p1 = p->name, p2 = name; *p1 && *p1 == *p2; p1++, p2++) {
                continue;
        }
        if (*p1 != '\0' || p2 != cp - 1) {
                return NULL;
        }

        if (Hash_FindEntry(&p->files, cp) == NULL) {
                if (DEBUG(DIR)) {
                        fprintf(debug_file, "   must be here but isn't -- returning\n");
                }
                /* Return empty string: terminates search */
                return bmake_strdup("");
        }

        p->hits += 1;
        hits += 1;
        if (DEBUG(DIR)) {
                fprintf(debug_file, "   returning %s\n", name);
        }
        return (bmake_strdup(name));
}

/*-
 *-----------------------------------------------------------------------
 * DirFindDot  --
 *      Find the file given on "." or curdir
 *
 * Results:
 *      The path to the file or NULL. This path is guaranteed to be in a
 *      different part of memory than name and so may be safely free'd.
 *
 * Side Effects:
 *      Hit counts change
 *-----------------------------------------------------------------------
 */
static char *
DirFindDot(Boolean hasSlash MAKE_ATTR_UNUSED, const char *name, const char *cp)
{

        if (Hash_FindEntry(&dot->files, cp) != NULL) {
            if (DEBUG(DIR)) {
                fprintf(debug_file, "   in '.'\n");
            }
            hits += 1;
            dot->hits += 1;
            return (bmake_strdup(name));
        }
        if (cur &&
            Hash_FindEntry(&cur->files, cp) != NULL) {
            if (DEBUG(DIR)) {
                fprintf(debug_file, "   in ${.CURDIR} = %s\n", cur->name);
            }
            hits += 1;
            cur->hits += 1;
            return str_concat(cur->name, cp, STR_ADDSLASH);
        }

        return NULL;
}

/*-
 *-----------------------------------------------------------------------
 * Dir_FindFile  --
 *      Find the file with the given name along the given search path.
 *
 * Input:
 *      name            the file to find
 *      path            the Lst of directories to search
 *
 * Results:
 *      The path to the file or NULL. This path is guaranteed to be in a
 *      different part of memory than name and so may be safely free'd.
 *
 * Side Effects:
 *      If the file is found in a directory which is not on the path
 *      already (either 'name' is absolute or it is a relative path
 *      [ dir1/.../dirn/file ] which exists below one of the directories
 *      already on the search path), its directory is added to the end
 *      of the path on the assumption that there will be more files in
 *      that directory later on. Sometimes this is true. Sometimes not.
 *-----------------------------------------------------------------------
 */
char *
Dir_FindFile(const char *name, Lst path)
{
    LstNode       ln;                   /* a list element */
    char          *file;                /* the current filename to check */
    Path          *p;                   /* current path member */
    const char    *cp;                  /* Terminal name of file */
    Boolean       hasLastDot = FALSE;   /* true we should search dot last */
    Boolean       hasSlash;             /* true if 'name' contains a / */
    struct stat   stb;                  /* Buffer for stat, if necessary */
    Hash_Entry    *entry;               /* Entry for mtimes table */
    const char   *trailing_dot = ".";

    /*
     * Find the final component of the name and note whether it has a
     * slash in it (the name, I mean)
     */
    cp = strrchr(name, '/');
    if (cp) {
        hasSlash = TRUE;
        cp += 1;
    } else {
        hasSlash = FALSE;
        cp = name;
    }

    if (DEBUG(DIR)) {
        fprintf(debug_file, "Searching for %s ...", name);
    }

    if (Lst_Open(path) == FAILURE) {
        if (DEBUG(DIR)) {
            fprintf(debug_file, "couldn't open path, file not found\n");
        }
        misses += 1;
        return NULL;
    }

    if ((ln = Lst_First(path)) != NULL) {
        p = (Path *)Lst_Datum(ln);
        if (p == dotLast) {
            hasLastDot = TRUE;
            if (DEBUG(DIR))
                fprintf(debug_file, "[dot last]...");
        }
    }
    if (DEBUG(DIR)) {
        fprintf(debug_file, "\n");
    }

    /*
     * If there's no leading directory components or if the leading
     * directory component is exactly `./', consult the cached contents
     * of each of the directories on the search path.
     */
    if (!hasSlash || (cp - name == 2 && *name == '.')) {
            /*
             * We look through all the directories on the path seeking one which
             * contains the final component of the given name.  If such a beast
             * is found, we concatenate the directory name and the final
             * component and return the resulting string. If we don't find any
             * such thing, we go on to phase two...
             * 
             * No matter what, we always look for the file in the current
             * directory before anywhere else (unless we found the magic
             * DOTLAST path, in which case we search it last) and we *do not*
             * add the ./ to it if it exists.
             * This is so there are no conflicts between what the user
             * specifies (fish.c) and what pmake finds (./fish.c).
             */
            if (!hasLastDot &&
                        (file = DirFindDot(hasSlash, name, cp)) != NULL) {
                    Lst_Close(path);
                    return file;
            }

            while ((ln = Lst_Next(path)) != NULL) {
                p = (Path *)Lst_Datum(ln);
                if (p == dotLast)
                    continue;
                if ((file = DirLookup(p, name, cp, hasSlash)) != NULL) {
                    Lst_Close(path);
                    return file;
                }
            }

            if (hasLastDot &&
                        (file = DirFindDot(hasSlash, name, cp)) != NULL) {
                    Lst_Close(path);
                    return file;
            }
    }
    Lst_Close(path);

    /*
     * We didn't find the file on any directory in the search path.
     * If the name doesn't contain a slash, that means it doesn't exist.
     * If it *does* contain a slash, however, there is still hope: it
     * could be in a subdirectory of one of the members of the search
     * path. (eg. /usr/include and sys/types.h. The above search would
     * fail to turn up types.h in /usr/include, but it *is* in
     * /usr/include/sys/types.h).
     * [ This no longer applies: If we find such a beast, we assume there
     * will be more (what else can we assume?) and add all but the last
     * component of the resulting name onto the search path (at the
     * end).]
     * This phase is only performed if the file is *not* absolute.
     */
    if (!hasSlash) {
        if (DEBUG(DIR)) {
            fprintf(debug_file, "   failed.\n");
        }
        misses += 1;
        return NULL;
    }

    if (*cp == '\0') {
        /* we were given a trailing "/" */
        cp = trailing_dot;
    }

    if (name[0] != '/') {
        Boolean checkedDot = FALSE;

        if (DEBUG(DIR)) {
            fprintf(debug_file, "   Trying subdirectories...\n");
        }

        if (!hasLastDot) {
                if (dot) {
                        checkedDot = TRUE;
                        if ((file = DirLookupSubdir(dot, name)) != NULL)
                                return file;
                }
                if (cur && (file = DirLookupSubdir(cur, name)) != NULL)
                        return file;
        }

        (void)Lst_Open(path);
        while ((ln = Lst_Next(path)) != NULL) {
            p = (Path *)Lst_Datum(ln);
            if (p == dotLast)
                continue;
            if (p == dot) {
                    if (checkedDot)
                            continue;
                checkedDot = TRUE;
            }
            if ((file = DirLookupSubdir(p, name)) != NULL) {
                Lst_Close(path);
                return file;
            }
        }
        Lst_Close(path);

        if (hasLastDot) {
                if (dot && !checkedDot) {
                        checkedDot = TRUE;
                        if ((file = DirLookupSubdir(dot, name)) != NULL)
                                return file;
                }
                if (cur && (file = DirLookupSubdir(cur, name)) != NULL)
                        return file;
        }

        if (checkedDot) {
            /*
             * Already checked by the given name, since . was in the path,
             * so no point in proceeding...
             */
            if (DEBUG(DIR)) {
                fprintf(debug_file, "   Checked . already, returning NULL\n");
            }
            return NULL;
        }

    } else { /* name[0] == '/' */

        /*
         * For absolute names, compare directory path prefix against the
         * the directory path of each member on the search path for an exact
         * match. If we have an exact match on any member of the search path,
         * use the cached contents of that member to lookup the final file
         * component. If that lookup fails we can safely assume that the
         * file does not exist at all.  This is signified by DirLookupAbs()
         * returning an empty string.
         */
        if (DEBUG(DIR)) {
            fprintf(debug_file, "   Trying exact path matches...\n");
        }

        if (!hasLastDot && cur && (file = DirLookupAbs(cur, name, cp)) != NULL)
            return *file?file:NULL;

        (void)Lst_Open(path);
        while ((ln = Lst_Next(path)) != NULL) {
            p = (Path *)Lst_Datum(ln);
            if (p == dotLast)
                continue;
            if ((file = DirLookupAbs(p, name, cp)) != NULL) {
                Lst_Close(path);
                return *file?file:NULL;
            }
        }
        Lst_Close(path);

        if (hasLastDot && cur && (file = DirLookupAbs(cur, name, cp)) != NULL)
            return *file?file:NULL;
    }

    /*
     * Didn't find it that way, either. Sigh. Phase 3. Add its directory
     * onto the search path in any case, just in case, then look for the
     * thing in the hash table. If we find it, grand. We return a new
     * copy of the name. Otherwise we sadly return a NULL pointer. Sigh.
     * Note that if the directory holding the file doesn't exist, this will
     * do an extra search of the final directory on the path. Unless something
     * weird happens, this search won't succeed and life will be groovy.
     *
     * Sigh. We cannot add the directory onto the search path because
     * of this amusing case:
     * $(INSTALLDIR)/$(FILE): $(FILE)
     *
     * $(FILE) exists in $(INSTALLDIR) but not in the current one.
     * When searching for $(FILE), we will find it in $(INSTALLDIR)
     * b/c we added it here. This is not good...
     */
#ifdef notdef
    if (cp == traling_dot) {
        cp = strrchr(name, '/');
        cp += 1;
    }
    cp[-1] = '\0';
    (void)Dir_AddDir(path, name);
    cp[-1] = '/';

    bigmisses += 1;
    ln = Lst_Last(path);
    if (ln == NULL) {
        return NULL;
    } else {
        p = (Path *)Lst_Datum(ln);
    }

    if (Hash_FindEntry(&p->files, cp) != NULL) {
        return (bmake_strdup(name));
    } else {
        return NULL;
    }
#else /* !notdef */
    if (DEBUG(DIR)) {
        fprintf(debug_file, "   Looking for \"%s\" ...\n", name);
    }

    bigmisses += 1;
    entry = Hash_FindEntry(&mtimes, name);
    if (entry != NULL) {
        if (DEBUG(DIR)) {
            fprintf(debug_file, "   got it (in mtime cache)\n");
        }
        return(bmake_strdup(name));
    } else if (cached_stat(name, &stb) == 0) {
        if (DEBUG(DIR)) {
            fprintf(debug_file, "   Caching %s for %s\n", Targ_FmtTime(stb.st_mtime),
                    name);
        }
        return (bmake_strdup(name));
    } else {
        if (DEBUG(DIR)) {
            fprintf(debug_file, "   failed. Returning NULL\n");
        }
        return NULL;
    }
#endif /* notdef */
}


/*-
 *-----------------------------------------------------------------------
 * Dir_FindHereOrAbove  --
 *      search for a path starting at a given directory and then working 
 *      our way up towards the root.
 *
 * Input:
 *      here            starting directory
 *      search_path     the path we are looking for
 *      result          the result of a successful search is placed here
 *      rlen            the length of the result buffer 
 *                      (typically MAXPATHLEN + 1)
 *
 * Results:
 *      0 on failure, 1 on success [in which case the found path is put
 *      in the result buffer].
 *
 * Side Effects:
 *-----------------------------------------------------------------------
 */
int 
Dir_FindHereOrAbove(char *here, char *search_path, char *result, int rlen) {

        struct stat st;
        char dirbase[MAXPATHLEN + 1], *db_end;
        char try[MAXPATHLEN + 1], *try_end;

        /* copy out our starting point */
        snprintf(dirbase, sizeof(dirbase), "%s", here);
        db_end = dirbase + strlen(dirbase);

        /* loop until we determine a result */
        while (1) {

                /* try and stat(2) it ... */
                snprintf(try, sizeof(try), "%s/%s", dirbase, search_path);
                if (cached_stat(try, &st) != -1) {
                        /*
                         * success!  if we found a file, chop off
                         * the filename so we return a directory.
                         */
                        if ((st.st_mode & S_IFMT) != S_IFDIR) {
                                try_end = try + strlen(try);
                                while (try_end > try && *try_end != '/')
                                        try_end--;
                                if (try_end > try) 
                                        *try_end = 0;   /* chop! */
                        }

                        /*
                         * done!
                         */
                        snprintf(result, rlen, "%s", try);
                        return(1);
                }

                /* 
                 * nope, we didn't find it.  if we used up dirbase we've
                 * reached the root and failed.
                 */
                if (db_end == dirbase)
                        break;          /* failed! */

                /*
                 * truncate dirbase from the end to move up a dir
                 */
                while (db_end > dirbase && *db_end != '/')
                        db_end--;
                *db_end = 0;            /* chop! */

        } /* while (1) */

        /*
         * we failed... 
         */
        return(0);
}

/*-
 *-----------------------------------------------------------------------
 * Dir_MTime  --
 *      Find the modification time of the file described by gn along the
 *      search path dirSearchPath.
 *
 * Input:
 *      gn              the file whose modification time is desired
 *
 * Results:
 *      The modification time or 0 if it doesn't exist
 *
 * Side Effects:
 *      The modification time is placed in the node's mtime slot.
 *      If the node didn't have a path entry before, and Dir_FindFile
 *      found one for it, the full name is placed in the path slot.
 *-----------------------------------------------------------------------
 */
int
Dir_MTime(GNode *gn, Boolean recheck)
{
    char          *fullName;  /* the full pathname of name */
    struct stat   stb;        /* buffer for finding the mod time */
    Hash_Entry    *entry;

    if (gn->type & OP_ARCHV) {
        return Arch_MTime(gn);
    } else if (gn->type & OP_PHONY) {
        gn->mtime = 0;
        return 0;
    } else if (gn->path == NULL) {
        if (gn->type & OP_NOPATH)
            fullName = NULL;
        else {
            fullName = Dir_FindFile(gn->name, Suff_FindPath(gn));
            if (fullName == NULL && gn->flags & FROM_DEPEND &&
                !Lst_IsEmpty(gn->iParents)) {
                char *cp;

                cp = strrchr(gn->name, '/');
                if (cp) {
                    /*
                     * This is an implied source, and it may have moved,
                     * see if we can find it via the current .PATH
                     */
                    cp++;
                        
                    fullName = Dir_FindFile(cp, Suff_FindPath(gn));
                    if (fullName) {
                        /*
                         * Put the found file in gn->path
                         * so that we give that to the compiler.
                         */
                        gn->path = bmake_strdup(fullName);
                        if (!Job_RunTarget(".STALE", gn->fname))
                            fprintf(stdout,
                                "%s: %s, %d: ignoring stale %s for %s, "
                                "found %s\n", progname, gn->fname, gn->lineno,
                                makeDependfile, gn->name, fullName);
                    }
                }
            }
            if (DEBUG(DIR))
                fprintf(debug_file, "Found '%s' as '%s'\n",
                        gn->name, fullName ? fullName : "(not found)" );
        }
    } else {
        fullName = gn->path;
    }

    if (fullName == NULL) {
        fullName = bmake_strdup(gn->name);
    }

    if (!recheck)
        entry = Hash_FindEntry(&mtimes, fullName);
    else
        entry = NULL;
    if (entry != NULL) {
        stb.st_mtime = Hash_GetTimeValue(entry);
        if (DEBUG(DIR)) {
            fprintf(debug_file, "Using cached time %s for %s\n",
                    Targ_FmtTime(stb.st_mtime), fullName);
        }
    } else if (cached_stats(&mtimes, fullName, &stb, recheck ? CST_UPDATE : 0) < 0) {
        if (gn->type & OP_MEMBER) {
            if (fullName != gn->path)
                free(fullName);
            return Arch_MemMTime(gn);
        } else {
            stb.st_mtime = 0;
        }
    }

    if (fullName && gn->path == NULL) {
        gn->path = fullName;
    }

    gn->mtime = stb.st_mtime;
    return (gn->mtime);
}

/*-
 *-----------------------------------------------------------------------
 * Dir_AddDir --
 *      Add the given name to the end of the given path. The order of
 *      the arguments is backwards so ParseDoDependency can do a
 *      Lst_ForEach of its list of paths...
 *
 * Input:
 *      path            the path to which the directory should be
 *                      added
 *      name            the name of the directory to add
 *
 * Results:
 *      none
 *
 * Side Effects:
 *      A structure is added to the list and the directory is
 *      read and hashed.
 *-----------------------------------------------------------------------
 */
Path *
Dir_AddDir(Lst path, const char *name)
{
    LstNode       ln = NULL; /* node in case Path structure is found */
    Path          *p = NULL;  /* pointer to new Path structure */
    DIR           *d;         /* for reading directory */
    struct dirent *dp;        /* entry in directory */

    if (strcmp(name, ".DOTLAST") == 0) {
        ln = Lst_Find(path, name, DirFindName);
        if (ln != NULL)
            return (Path *)Lst_Datum(ln);
        else {
            dotLast->refCount += 1;
            (void)Lst_AtFront(path, dotLast);
        }
    }

    if (path)
        ln = Lst_Find(openDirectories, name, DirFindName);
    if (ln != NULL) {
        p = (Path *)Lst_Datum(ln);
        if (path && Lst_Member(path, p) == NULL) {
            p->refCount += 1;
            (void)Lst_AtEnd(path, p);
        }
    } else {
        if (DEBUG(DIR)) {
            fprintf(debug_file, "Caching %s ...", name);
        }

        if ((d = opendir(name)) != NULL) {
            p = bmake_malloc(sizeof(Path));
            p->name = bmake_strdup(name);
            p->hits = 0;
            p->refCount = 1;
            Hash_InitTable(&p->files, -1);

            while ((dp = readdir(d)) != NULL) {
#if defined(sun) && defined(d_ino) /* d_ino is a sunos4 #define for d_fileno */
                /*
                 * The sun directory library doesn't check for a 0 inode
                 * (0-inode slots just take up space), so we have to do
                 * it ourselves.
                 */
                if (dp->d_fileno == 0) {
                    continue;
                }
#endif /* sun && d_ino */
                (void)Hash_CreateEntry(&p->files, dp->d_name, NULL);
            }
            (void)closedir(d);
            (void)Lst_AtEnd(openDirectories, p);
            if (path != NULL)
                (void)Lst_AtEnd(path, p);
        }
        if (DEBUG(DIR)) {
            fprintf(debug_file, "done\n");
        }
    }
    return p;
}

/*-
 *-----------------------------------------------------------------------
 * Dir_CopyDir --
 *      Callback function for duplicating a search path via Lst_Duplicate.
 *      Ups the reference count for the directory.
 *
 * Results:
 *      Returns the Path it was given.
 *
 * Side Effects:
 *      The refCount of the path is incremented.
 *
 *-----------------------------------------------------------------------
 */
void *
Dir_CopyDir(void *p)
{
    ((Path *)p)->refCount += 1;

    return (p);
}

/*-
 *-----------------------------------------------------------------------
 * Dir_MakeFlags --
 *      Make a string by taking all the directories in the given search
 *      path and preceding them by the given flag. Used by the suffix
 *      module to create variables for compilers based on suffix search
 *      paths.
 *
 * Input:
 *      flag            flag which should precede each directory
 *      path            list of directories
 *
 * Results:
 *      The string mentioned above. Note that there is no space between
 *      the given flag and each directory. The empty string is returned if
 *      Things don't go well.
 *
 * Side Effects:
 *      None
 *-----------------------------------------------------------------------
 */
char *
Dir_MakeFlags(const char *flag, Lst path)
{
    char          *str;   /* the string which will be returned */
    char          *s1, *s2;/* the current directory preceded by 'flag' */
    LstNode       ln;     /* the node of the current directory */
    Path          *p;     /* the structure describing the current directory */

    str = bmake_strdup("");

    if (Lst_Open(path) == SUCCESS) {
        while ((ln = Lst_Next(path)) != NULL) {
            p = (Path *)Lst_Datum(ln);
            s2 = str_concat(flag, p->name, 0);
            str = str_concat(s1 = str, s2, STR_ADDSPACE);
            free(s1);
            free(s2);
        }
        Lst_Close(path);
    }

    return (str);
}

/*-
 *-----------------------------------------------------------------------
 * Dir_Destroy --
 *      Nuke a directory descriptor, if possible. Callback procedure
 *      for the suffixes module when destroying a search path.
 *
 * Input:
 *      pp              The directory descriptor to nuke
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      If no other path references this directory (refCount == 0),
 *      the Path and all its data are freed.
 *
 *-----------------------------------------------------------------------
 */
void
Dir_Destroy(void *pp)
{
    Path          *p = (Path *)pp;
    p->refCount -= 1;

    if (p->refCount == 0) {
        LstNode ln;

        ln = Lst_Member(openDirectories, p);
        (void)Lst_Remove(openDirectories, ln);

        Hash_DeleteTable(&p->files);
        free(p->name);
        free(p);
    }
}

/*-
 *-----------------------------------------------------------------------
 * Dir_ClearPath --
 *      Clear out all elements of the given search path. This is different
 *      from destroying the list, notice.
 *
 * Input:
 *      path            Path to clear
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      The path is set to the empty list.
 *
 *-----------------------------------------------------------------------
 */
void
Dir_ClearPath(Lst path)
{
    Path    *p;
    while (!Lst_IsEmpty(path)) {
        p = (Path *)Lst_DeQueue(path);
        Dir_Destroy(p);
    }
}


/*-
 *-----------------------------------------------------------------------
 * Dir_Concat --
 *      Concatenate two paths, adding the second to the end of the first.
 *      Makes sure to avoid duplicates.
 *
 * Input:
 *      path1           Dest
 *      path2           Source
 *
 * Results:
 *      None
 *
 * Side Effects:
 *      Reference counts for added dirs are upped.
 *
 *-----------------------------------------------------------------------
 */
void
Dir_Concat(Lst path1, Lst path2)
{
    LstNode ln;
    Path    *p;

    for (ln = Lst_First(path2); ln != NULL; ln = Lst_Succ(ln)) {
        p = (Path *)Lst_Datum(ln);
        if (Lst_Member(path1, p) == NULL) {
            p->refCount += 1;
            (void)Lst_AtEnd(path1, p);
        }
    }
}

/********** DEBUG INFO **********/
void
Dir_PrintDirectories(void)
{
    LstNode     ln;
    Path        *p;

    fprintf(debug_file, "#*** Directory Cache:\n");
    fprintf(debug_file, "# Stats: %d hits %d misses %d near misses %d losers (%d%%)\n",
              hits, misses, nearmisses, bigmisses,
              (hits+bigmisses+nearmisses ?
               hits * 100 / (hits + bigmisses + nearmisses) : 0));
    fprintf(debug_file, "# %-20s referenced\thits\n", "directory");
    if (Lst_Open(openDirectories) == SUCCESS) {
        while ((ln = Lst_Next(openDirectories)) != NULL) {
            p = (Path *)Lst_Datum(ln);
            fprintf(debug_file, "# %-20s %10d\t%4d\n", p->name, p->refCount, p->hits);
        }
        Lst_Close(openDirectories);
    }
}

static int
DirPrintDir(void *p, void *dummy)
{
    fprintf(debug_file, "%s ", ((Path *)p)->name);
    return (dummy ? 0 : 0);
}

void
Dir_PrintPath(Lst path)
{
    Lst_ForEach(path, DirPrintDir, NULL);
}