path: root/source3/smbd/dir.c

/* 
   Unix SMB/CIFS implementation.
   Directory handling routines
   Copyright (C) Andrew Tridgell 1992-1998
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

/*
   This module implements directory related functions for Samba.
*/

typedef struct _dptr_struct {
	struct _dptr_struct *next, *prev;
	int dnum;
	uint16 spid;
	connection_struct *conn;
	void *ptr;
	BOOL expect_close;
	char *wcard; /* Field only used for trans2_ searches */
	uint16 attr; /* Field only used for trans2_ searches */
	char *path;
} dptr_struct;

static struct bitmap *dptr_bmap;
static dptr_struct *dirptrs;

static int dptrs_open = 0;

#define INVALID_DPTR_KEY (-3)

/****************************************************************************
 Initialise the dir bitmap.
****************************************************************************/

void init_dptrs(void)
{
  static BOOL dptrs_init=False;

  if (dptrs_init)
    return;

  dptr_bmap = bitmap_allocate(MAX_DIRECTORY_HANDLES);

  if (!dptr_bmap)
    exit_server("out of memory in init_dptrs");

  dptrs_init = True;
}

/****************************************************************************
 Idle a dptr - the directory is closed but the control info is kept.
****************************************************************************/

static void dptr_idle(dptr_struct *dptr)
{
  if (dptr->ptr) {
    DEBUG(4,("Idling dptr dnum %d\n",dptr->dnum));
    dptrs_open--;
    CloseDir(dptr->ptr);
    dptr->ptr = NULL;
  }
}

/****************************************************************************
 Idle the oldest dptr.
****************************************************************************/

static void dptr_idleoldest(void)
{
  dptr_struct *dptr;

  /*
   * Go to the end of the list.
   */
  for(dptr = dirptrs; dptr && dptr->next; dptr = dptr->next)
    ;

  if(!dptr) {
    DEBUG(0,("No dptrs available to idle ?\n"));
    return;
  }

  /*
   * Idle the oldest pointer.
   */

  for(; dptr; dptr = dptr->prev) {
    if (dptr->ptr) {
      dptr_idle(dptr);
      return;
    }
  }
}

/****************************************************************************
 Get the dptr_struct for a dir index.
****************************************************************************/

static dptr_struct *dptr_get(int key, BOOL forclose)
{
  dptr_struct *dptr;

  for(dptr = dirptrs; dptr; dptr = dptr->next) {
    if(dptr->dnum == key) {
      if (!forclose && !dptr->ptr) {
        if (dptrs_open >= MAX_OPEN_DIRECTORIES)
          dptr_idleoldest();
        DEBUG(4,("Reopening dptr key %d\n",key));
        if ((dptr->ptr = OpenDir(dptr->conn, dptr->path, True)))
          dptrs_open++;
      }
      DLIST_PROMOTE(dirptrs,dptr);
      return dptr;
    }
  }
  return(NULL);
}

/****************************************************************************
 Get the dptr ptr for a dir index.
****************************************************************************/

static void *dptr_ptr(int key)
{
  dptr_struct *dptr = dptr_get(key, False);

  if (dptr)
    return(dptr->ptr);
  return(NULL);
}

/****************************************************************************
 Get the dir path for a dir index.
****************************************************************************/

char *dptr_path(int key)
{
  dptr_struct *dptr = dptr_get(key, False);

  if (dptr)
    return(dptr->path);
  return(NULL);
}

/****************************************************************************
 Get the dir wcard for a dir index (lanman2 specific).
****************************************************************************/

char *dptr_wcard(int key)
{
  dptr_struct *dptr = dptr_get(key, False);

  if (dptr)
    return(dptr->wcard);
  return(NULL);
}

/****************************************************************************
 Set the dir wcard for a dir index (lanman2 specific).
 Returns 0 on ok, 1 on fail.
****************************************************************************/

BOOL dptr_set_wcard(int key, char *wcard)
{
  dptr_struct *dptr = dptr_get(key, False);

  if (dptr) {
    dptr->wcard = wcard;
    return True;
  }
  return False;
}

/****************************************************************************
 Set the dir attrib for a dir index (lanman2 specific).
 Returns 0 on ok, 1 on fail.
****************************************************************************/

BOOL dptr_set_attr(int key, uint16 attr)
{
  dptr_struct *dptr = dptr_get(key, False);

  if (dptr) {
    dptr->attr = attr;
    return True;
  }
  return False;
}

/****************************************************************************
 Get the dir attrib for a dir index (lanman2 specific)
****************************************************************************/

uint16 dptr_attr(int key)
{
  dptr_struct *dptr = dptr_get(key, False);

  if (dptr)
    return(dptr->attr);
  return(0);
}

/****************************************************************************
 Close a dptr (internal func).
****************************************************************************/

static void dptr_close_internal(dptr_struct *dptr)
{
  DEBUG(4,("closing dptr key %d\n",dptr->dnum));

  DLIST_REMOVE(dirptrs, dptr);

  /* 
   * Free the dnum in the bitmap. Remember the dnum value is always 
   * biased by one with respect to the bitmap.
   */

  if(bitmap_query( dptr_bmap, dptr->dnum - 1) != True) {
    DEBUG(0,("dptr_close_internal : Error - closing dnum = %d and bitmap not set !\n",
			dptr->dnum ));
  }

  bitmap_clear(dptr_bmap, dptr->dnum - 1);

  if (dptr->ptr) {
    CloseDir(dptr->ptr);
    dptrs_open--;
  }

  /* Lanman 2 specific code */
  SAFE_FREE(dptr->wcard);
  string_set(&dptr->path,"");
  SAFE_FREE(dptr);
}

/****************************************************************************
 Close a dptr given a key.
****************************************************************************/

void dptr_close(int *key)
{
  dptr_struct *dptr;

  if(*key == INVALID_DPTR_KEY)
    return;

  /* OS/2 seems to use -1 to indicate "close all directories" */
  if (*key == -1) {
    dptr_struct *next;
    for(dptr = dirptrs; dptr; dptr = next) {
      next = dptr->next;
      dptr_close_internal(dptr);
    }
    *key = INVALID_DPTR_KEY;
    return;
  }

  dptr = dptr_get(*key, True);

  if (!dptr) {
    DEBUG(0,("Invalid key %d given to dptr_close\n", *key));
    return;
  }

  dptr_close_internal(dptr);

  *key = INVALID_DPTR_KEY;
}

/****************************************************************************
 Close all dptrs for a cnum.
****************************************************************************/

void dptr_closecnum(connection_struct *conn)
{
  dptr_struct *dptr, *next;
  for(dptr = dirptrs; dptr; dptr = next) {
    next = dptr->next;
    if (dptr->conn == conn)
      dptr_close_internal(dptr);
  }
}

/****************************************************************************
 Idle all dptrs for a cnum.
****************************************************************************/

void dptr_idlecnum(connection_struct *conn)
{
  dptr_struct *dptr;
  for(dptr = dirptrs; dptr; dptr = dptr->next) {
    if (dptr->conn == conn && dptr->ptr)
      dptr_idle(dptr);
  }
}

/****************************************************************************
 Close a dptr that matches a given path, only if it matches the spid also.
****************************************************************************/

void dptr_closepath(char *path,uint16 spid)
{
  dptr_struct *dptr, *next;
  for(dptr = dirptrs; dptr; dptr = next) {
    next = dptr->next;
    if (spid == dptr->spid && strequal(dptr->path,path))
      dptr_close_internal(dptr);
  }
}

/****************************************************************************
 Start a directory listing.
****************************************************************************/

static BOOL start_dir(connection_struct *conn,char *directory)
{
  DEBUG(5,("start_dir dir=%s\n",directory));

  if (!check_name(directory,conn))
    return(False);
  
  if (! *directory)
    directory = ".";

  conn->dirptr = OpenDir(conn, directory, True);
  if (conn->dirptr) {    
    dptrs_open++;
    string_set(&conn->dirpath,directory);
    return(True);
  }
  
  return(False);
}

/****************************************************************************
 Try and close the oldest handle not marked for
 expect close in the hope that the client has
 finished with that one.
****************************************************************************/

static void dptr_close_oldest(BOOL old)
{
  dptr_struct *dptr;

  /*
   * Go to the end of the list.
   */
  for(dptr = dirptrs; dptr && dptr->next; dptr = dptr->next)
    ;

  if(!dptr) {
    DEBUG(0,("No old dptrs available to close oldest ?\n"));
    return;
  }

  /*
   * If 'old' is true, close the oldest oldhandle dnum (ie. 1 < dnum < 256) that
   * does not have expect_close set. If 'old' is false, close
   * one of the new dnum handles.
   */

  for(; dptr; dptr = dptr->prev) {
    if ((old && (dptr->dnum < 256) && !dptr->expect_close) ||
        (!old && (dptr->dnum > 255))) {
      dptr_close_internal(dptr);
      return;
    }
  }
}

/****************************************************************************
 Create a new dir ptr. If the flag old_handle is true then we must allocate
 from the bitmap range 0 - 255 as old SMBsearch directory handles are only
 one byte long. If old_handle is false we allocate from the range
 256 - MAX_DIRECTORY_HANDLES. We bias the number we return by 1 to ensure
 a directory handle is never zero. All the above is folklore taught to
 me at Andrew's knee.... :-) :-). JRA.
****************************************************************************/

int dptr_create(connection_struct *conn,char *path, BOOL old_handle, BOOL expect_close,uint16 spid)
{
  dptr_struct *dptr;

  if (!start_dir(conn,path))
    return(-2); /* Code to say use a unix error return code. */

  if (dptrs_open >= MAX_OPEN_DIRECTORIES)
    dptr_idleoldest();

  dptr = (dptr_struct *)malloc(sizeof(dptr_struct));
  if(!dptr) {
    DEBUG(0,("malloc fail in dptr_create.\n"));
    return -1;
  }

  ZERO_STRUCTP(dptr);

  if(old_handle) {

    /*
     * This is an old-style SMBsearch request. Ensure the
     * value we return will fit in the range 1-255.
     */

    dptr->dnum = bitmap_find(dptr_bmap, 0);

    if(dptr->dnum == -1 || dptr->dnum > 254) {

      /*
       * Try and close the oldest handle not marked for
       * expect close in the hope that the client has
       * finished with that one.
       */

      dptr_close_oldest(True);

      /* Now try again... */
      dptr->dnum = bitmap_find(dptr_bmap, 0);

      if(dptr->dnum == -1 || dptr->dnum > 254) {
        DEBUG(0,("dptr_create: returned %d: Error - all old dirptrs in use ?\n", dptr->dnum));
        SAFE_FREE(dptr);
        return -1;
      }
    }
  } else {

    /*
     * This is a new-style trans2 request. Allocate from
     * a range that will return 256 - MAX_DIRECTORY_HANDLES.
     */

    dptr->dnum = bitmap_find(dptr_bmap, 255);

    if(dptr->dnum == -1 || dptr->dnum < 255) {

      /*
       * Try and close the oldest handle close in the hope that
       * the client has finished with that one. This will only
       * happen in the case of the Win98 client bug where it leaks
       * directory handles.
       */

      dptr_close_oldest(False);

      /* Now try again... */
      dptr->dnum = bitmap_find(dptr_bmap, 255);

      if(dptr->dnum == -1 || dptr->dnum < 255) {
        DEBUG(0,("dptr_create: returned %d: Error - all new dirptrs in use ?\n", dptr->dnum));
        SAFE_FREE(dptr);
        return -1;
      }
    }
  }

  bitmap_set(dptr_bmap, dptr->dnum);

  dptr->dnum += 1; /* Always bias the dnum by one - no zero dnums allowed. */

  dptr->ptr = conn->dirptr;
  string_set(&dptr->path,path);
  dptr->conn = conn;
  dptr->spid = spid;
  dptr->expect_close = expect_close;
  dptr->wcard = NULL; /* Only used in lanman2 searches */
  dptr->attr = 0; /* Only used in lanman2 searches */

  DLIST_ADD(dirptrs, dptr);

  DEBUG(3,("creating new dirptr %d for path %s, expect_close = %d\n",
	   dptr->dnum,path,expect_close));  

  return(dptr->dnum);
}

/****************************************************************************
 Fill the 5 byte server reserved dptr field.
****************************************************************************/

BOOL dptr_fill(char *buf1,unsigned int key)
{
  unsigned char *buf = (unsigned char *)buf1;
  void *p = dptr_ptr(key);
  uint32 offset;
  if (!p) {
    DEBUG(1,("filling null dirptr %d\n",key));
    return(False);
  }
  offset = TellDir(p);
  DEBUG(6,("fill on key %u dirptr 0x%lx now at %d\n",key,
	   (long)p,(int)offset));
  buf[0] = key;
  SIVAL(buf,1,offset | DPTR_MASK);
  return(True);
}

/****************************************************************************
 Fetch the dir ptr and seek it given the 5 byte server field.
****************************************************************************/

void *dptr_fetch(char *buf,int *num)
{
  unsigned int key = *(unsigned char *)buf;
  void *p = dptr_ptr(key);
  uint32 offset;
  if (!p) {
    DEBUG(3,("fetched null dirptr %d\n",key));
    return(NULL);
  }
  *num = key;
  offset = IVAL(buf,1)&~DPTR_MASK;
  SeekDir(p,offset);
  DEBUG(3,("fetching dirptr %d for path %s at offset %d\n",
	   key,dptr_path(key),offset));
  return(p);
}

/****************************************************************************
 Fetch the dir ptr.
****************************************************************************/

void *dptr_fetch_lanman2(int dptr_num)
{
  void *p = dptr_ptr(dptr_num);

  if (!p) {
    DEBUG(3,("fetched null dirptr %d\n",dptr_num));
    return(NULL);
  }
  DEBUG(3,("fetching dirptr %d for path %s\n",dptr_num,dptr_path(dptr_num)));
  return(p);
}

/****************************************************************************
 Check a filetype for being valid.
****************************************************************************/

BOOL dir_check_ftype(connection_struct *conn,int mode,SMB_STRUCT_STAT *st,int dirtype)
{
  if (((mode & ~dirtype) & (aHIDDEN | aSYSTEM | aDIR)) != 0)
    return False;
  return True;
}

static BOOL mangle_mask_match(connection_struct *conn, char *filename, char *mask)
{
	mangle_map(filename,True,False,SNUM(conn));
	return mask_match(filename,mask,False);
}

/****************************************************************************
 Get an 8.3 directory entry.
****************************************************************************/

BOOL get_dir_entry(connection_struct *conn,char *mask,int dirtype,char *fname,
                   SMB_OFF_T *size,int *mode,time_t *date,BOOL check_descend)
{
  char *dname;
  BOOL found = False;
  SMB_STRUCT_STAT sbuf;
  pstring path;
  pstring pathreal;
  BOOL isrootdir;
  pstring filename;
  BOOL needslash;

  *path = *pathreal = *filename = 0;

  isrootdir = (strequal(conn->dirpath,"./") ||
	       strequal(conn->dirpath,".") ||
	       strequal(conn->dirpath,"/"));
  
  needslash = ( conn->dirpath[strlen(conn->dirpath) -1] != '/');

  if (!conn->dirptr)
    return(False);

  while (!found)
  {
    dname = ReadDirName(conn->dirptr);

    DEBUG(6,("readdir on dirptr 0x%lx now at offset %d\n",
          (long)conn->dirptr,TellDir(conn->dirptr)));
      
    if (dname == NULL) 
      return(False);
      
    pstrcpy(filename,dname);      

    /* notice the special *.* handling. This appears to be the only difference
       between the wildcard handling in this routine and in the trans2 routines.
       see masktest for a demo
    */
    if ((strcmp(mask,"*.*") == 0) ||
	mask_match(filename,mask,False) ||
        mangle_mask_match(conn,filename,mask))
    {
      if (isrootdir && (strequal(filename,"..") || strequal(filename,".")))
        continue;

      if (!mangle_is_8_3(filename, False)) {
	      mangle_map(filename,True,False,SNUM(conn));
      }

      pstrcpy(fname,filename);
      *path = 0;
      pstrcpy(path,conn->dirpath);
      if(needslash)
        pstrcat(path,"/");
      pstrcpy(pathreal,path);
      pstrcat(path,fname);
      pstrcat(pathreal,dname);
      if (conn->vfs_ops.stat(conn, pathreal, &sbuf) != 0)
      {
        DEBUG(5,("Couldn't stat 1 [%s]. Error = %s\n",path, strerror(errno) ));
        continue;
      }
	  
      *mode = dos_mode(conn,pathreal,&sbuf);

      if (!dir_check_ftype(conn,*mode,&sbuf,dirtype)) 
      {
        DEBUG(5,("[%s] attribs didn't match %x\n",filename,dirtype));
        continue;
      }

      *size = sbuf.st_size;
      *date = sbuf.st_mtime;

      DEBUG(3,("get_dir_entry mask=[%s] found %s fname=%s\n",mask, pathreal,fname));
	  
      found = True;
    }
  }

  return(found);
}



typedef struct
{
  int pos;
  int numentries;
  int mallocsize;
  char *data;
  char *current;
} Dir;

/*******************************************************************
 Check to see if a user can read a file. This is only approximate,
 it is used as part of the "hide unreadable" option. Don't
 use it for anything security sensitive.
********************************************************************/

static BOOL user_can_read_file(connection_struct *conn, char *name, SMB_STRUCT_STAT *pst)
{
	extern struct current_user current_user;
	SEC_DESC *psd = NULL;
	size_t sd_size;
	files_struct *fsp;
	int smb_action;
	int access_mode;
	NTSTATUS status;
	uint32 access_granted;

	/*
	 * If user is a member of the Admin group
	 * we never hide files from them.
	 */

	if (conn->admin_user)
		return True;

	/* If we can't stat it does not show it */
	if (!VALID_STAT(*pst) && (vfs_stat(conn, name, pst) != 0))
		return False;

	/* Pseudo-open the file (note - no fd's created). */

	if(S_ISDIR(pst->st_mode))	
		 fsp = open_directory(conn, name, pst, 0, SET_DENY_MODE(DENY_NONE), (FILE_FAIL_IF_NOT_EXIST|FILE_EXISTS_OPEN),
			unix_mode(conn,aRONLY|aDIR, name), &smb_action);
	else
		fsp = open_file_shared1(conn, name, pst, FILE_READ_ATTRIBUTES, SET_DENY_MODE(DENY_NONE),
			(FILE_FAIL_IF_NOT_EXIST|FILE_EXISTS_OPEN), 0, 0, &access_mode, &smb_action);

	if (!fsp)
		return False;

	/* Get NT ACL -allocated in main loop talloc context. No free needed here. */
	sd_size = conn->vfs_ops.fget_nt_acl(fsp, fsp->fd, &psd);
	close_file(fsp, False);

	/* No access if SD get failed. */
	if (!sd_size)
		return False;

	return se_access_check(psd, current_user.nt_user_token, FILE_READ_DATA,
                                 &access_granted, &status);
}

/*******************************************************************
 Check to see if a user can write a file (and only files, we do not
 check dirs on this one). This is only approximate,
 it is used as part of the "hide unwriteable" option. Don't
 use it for anything security sensitive.
********************************************************************/

static BOOL user_can_write_file(connection_struct *conn, char *name, SMB_STRUCT_STAT *pst)
{
	extern struct current_user current_user;
	SEC_DESC *psd = NULL;
	size_t sd_size;
	files_struct *fsp;
	int smb_action;
	int access_mode;
	NTSTATUS status;
	uint32 access_granted;

	/*
	 * If user is a member of the Admin group
	 * we never hide files from them.
	 */

	if (conn->admin_user)
		return True;

	/* If we can't stat it does not show it */
	if (!VALID_STAT(*pst) && (vfs_stat(conn, name, pst) != 0))
		return False;

	/* Pseudo-open the file (note - no fd's created). */

	if(S_ISDIR(pst->st_mode))	
		return True;
	else
		fsp = open_file_shared1(conn, name, pst, FILE_WRITE_ATTRIBUTES, SET_DENY_MODE(DENY_NONE),
			(FILE_FAIL_IF_NOT_EXIST|FILE_EXISTS_OPEN), 0, 0, &access_mode, &smb_action);

	if (!fsp)
		return False;

	/* Get NT ACL -allocated in main loop talloc context. No free needed here. */
	sd_size = conn->vfs_ops.fget_nt_acl(fsp, fsp->fd, &psd);
	close_file(fsp, False);

	/* No access if SD get failed. */
	if (!sd_size)
		return False;

	return se_access_check(psd, current_user.nt_user_token, FILE_WRITE_DATA,
                                 &access_granted, &status);
}

/*******************************************************************
  Is a file a "special" type ?
********************************************************************/

static BOOL file_is_special(connection_struct *conn, char *name, SMB_STRUCT_STAT *pst)
{
	/*
	 * If user is a member of the Admin group
	 * we never hide files from them.
	 */

	if (conn->admin_user)
		return True;

	/* If we can't stat it does not show it */
	if (!VALID_STAT(*pst) && (vfs_stat(conn, name, pst) != 0))
		return True;

	if (S_ISREG(pst->st_mode) || S_ISDIR(pst->st_mode) || S_ISLNK(pst->st_mode))
		return False;

	return True;
}

/*******************************************************************
 Open a directory.
********************************************************************/

void *OpenDir(connection_struct *conn, char *name, BOOL use_veto)
{
	Dir *dirp;
	char *n;
	DIR *p = conn->vfs_ops.opendir(conn,name);
	int used=0;

	if (!p)
		return(NULL);
	dirp = (Dir *)malloc(sizeof(Dir));
	if (!dirp) {
		DEBUG(0,("Out of memory in OpenDir\n"));
		conn->vfs_ops.closedir(conn,p);
		return(NULL);
	}
	dirp->pos = dirp->numentries = dirp->mallocsize = 0;
	dirp->data = dirp->current = NULL;

	while (True) {
		int l;
		BOOL normal_entry = True;
		SMB_STRUCT_STAT st;
		char *entry = NULL;

		if (used == 0) {
			n = ".";
			normal_entry = False;
		} else if (used == 2) {
			n = "..";
			normal_entry = False;
		} else {
			n = vfs_readdirname(conn, p);
			if (n == NULL)
				break;
			if ((strcmp(".",n) == 0) ||(strcmp("..",n) == 0))
				continue;
			normal_entry = True;
	    	}

		ZERO_STRUCT(st);
		l = strlen(n)+1;

		/* If it's a vetoed file, pretend it doesn't even exist */
		if (normal_entry && use_veto && conn && IS_VETO_PATH(conn, n))
			continue;

		/* Honour _hide unreadable_ option */
		if (normal_entry && conn && lp_hideunreadable(SNUM(conn))) {
			int ret=0;
      
			if (entry || asprintf(&entry, "%s/%s/%s", conn->origpath, name, n) > 0) {
				ret = user_can_read_file(conn, entry, &st);
			}
			if (!ret) {
				SAFE_FREE(entry);
				continue;
			}
		}

		/* Honour _hide unwriteable_ option */
		if (normal_entry && conn && lp_hideunwriteable_files(SNUM(conn))) {
			int ret=0;
      
			if (entry || asprintf(&entry, "%s/%s/%s", conn->origpath, name, n) > 0) {
				ret = user_can_write_file(conn, entry, &st);
			}
			if (!ret) {
				SAFE_FREE(entry);
				continue;
			}
		}

		/* Honour _hide_special_ option */
		if (normal_entry && conn && lp_hide_special_files(SNUM(conn))) {
			int ret=0;
      
			if (entry || asprintf(&entry, "%s/%s/%s", conn->origpath, name, n) > 0) {
				ret = file_is_special(conn, entry, &st);
			}
			if (ret) {
				SAFE_FREE(entry);
				continue;
			}
		}

		SAFE_FREE(entry);

		if (used + l > dirp->mallocsize) {
			int s = MAX(used+l,used+2000);
			char *r;
			r = (char *)Realloc(dirp->data,s);
			if (!r) {
				DEBUG(0,("Out of memory in OpenDir\n"));
					break;
			}
			dirp->data = r;
			dirp->mallocsize = s;
			dirp->current = dirp->data;
		}

		pstrcpy(dirp->data+used,n);
		used += l;
		dirp->numentries++;
	}

	conn->vfs_ops.closedir(conn,p);
	return((void *)dirp);
}


/*******************************************************************
 Close a directory.
********************************************************************/

void CloseDir(void *p)
{
  if (!p) return;    
  SAFE_FREE(((Dir *)p)->data);
  SAFE_FREE(p);
}

/*******************************************************************
 Read from a directory.
********************************************************************/

char *ReadDirName(void *p)
{
  char *ret;
  Dir *dirp = (Dir *)p;

  if (!dirp || !dirp->current || dirp->pos >= dirp->numentries) return(NULL);

  ret = dirp->current;
  dirp->current = skip_string(dirp->current,1);
  dirp->pos++;

  return(ret);
}


/*******************************************************************
 Seek a dir.
********************************************************************/

BOOL SeekDir(void *p,int pos)
{
  Dir *dirp = (Dir *)p;

  if (!dirp) return(False);

  if (pos < dirp->pos) {
    dirp->current = dirp->data;
    dirp->pos = 0;
  }

  while (dirp->pos < pos && ReadDirName(p)) ;

  return(dirp->pos == pos);
}

/*******************************************************************
 Tell a dir position.
********************************************************************/

int TellDir(void *p)
{
  Dir *dirp = (Dir *)p;

  if (!dirp) return(-1);
  
  return(dirp->pos);
}

/*******************************************************************************
 This section manages a global directory cache.
 (It should probably be split into a separate module.  crh)
********************************************************************************/

typedef struct {
  ubi_dlNode  node;
  char       *path;
  char       *name;
  char       *dname;
  int         snum;
} dir_cache_entry;

static ubi_dlNewList( dir_cache );

/*****************************************************************************
 Add an entry to the directory cache.
 Input:  path  -
         name  -
         dname -
         snum  -
 Output: None.
*****************************************************************************/

void DirCacheAdd( char *path, char *name, char *dname, int snum )
{
  int               pathlen;
  int               namelen;
  dir_cache_entry  *entry;

  /* Allocate the structure & string space in one go so that it can be freed
   * in one call to free().
   */
  pathlen = strlen( path ) +1;  /* Bytes required to store path (with nul). */
  namelen = strlen( name ) +1;  /* Bytes required to store name (with nul). */
  entry = (dir_cache_entry *)malloc( sizeof( dir_cache_entry )
                                   + pathlen
                                   + namelen
                                   + strlen( dname ) +1 );
  if( NULL == entry )   /* Not adding to the cache is not fatal,  */
    return;             /* so just return as if nothing happened. */

  /* Set pointers correctly and load values. */
  entry->path  = pstrcpy( (char *)&entry[1],       path);
  entry->name  = pstrcpy( &(entry->path[pathlen]), name);
  entry->dname = pstrcpy( &(entry->name[namelen]), dname);
  entry->snum  = snum;

  /* Add the new entry to the linked list. */
  (void)ubi_dlAddHead( dir_cache, entry );
  DEBUG( 4, ("Added dir cache entry %s %s -> %s\n", path, name, dname ) );

  /* Free excess cache entries. */
  while( DIRCACHESIZE < dir_cache->count )
    safe_free( ubi_dlRemTail( dir_cache ) );

}

/*****************************************************************************
 Search for an entry to the directory cache.
 Input:  path  -
         name  -
         snum  -
 Output: The dname string of the located entry, or NULL if the entry was
         not found.

 Notes:  This uses a linear search, which is is okay because of
         the small size of the cache.  Use a splay tree or hash
         for large caches.
*****************************************************************************/

char *DirCacheCheck( char *path, char *name, int snum )
{
  dir_cache_entry *entry;

  for( entry = (dir_cache_entry *)ubi_dlFirst( dir_cache );
       NULL != entry;
       entry = (dir_cache_entry *)ubi_dlNext( entry ) )
    {
    if( entry->snum == snum
        && 0 == strcmp( name, entry->name )
        && 0 == strcmp( path, entry->path ) )
      {
      DEBUG(4, ("Got dir cache hit on %s %s -> %s\n",path,name,entry->dname));
      return( entry->dname );
      }
    }

  return(NULL);
}

/*****************************************************************************
 Remove all cache entries which have an snum that matches the input.
 Input:  snum  -
 Output: None.
*****************************************************************************/

void DirCacheFlush(int snum)
{
	dir_cache_entry *entry;
	ubi_dlNodePtr    next;

	for(entry = (dir_cache_entry *)ubi_dlFirst( dir_cache ); 
	    NULL != entry; )  {
		next = ubi_dlNext( entry );
		if( entry->snum == snum )
			safe_free( ubi_dlRemThis( dir_cache, entry ) );
		entry = (dir_cache_entry *)next;
	}
}