/* * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1983, 1993 * The Regents of the University of California. All rights reserved. * * 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. */ #include <sys/param.h> #include <dirent.h> #include <stdlib.h> #include <unistd.h> /* * The option SINGLEUSE may be defined to say that a telldir * cookie may be used only once before it is freed. This option * is used to avoid having memory usage grow without bound. */ #define SINGLEUSE /* * One of these structures is malloced to describe the current directory * position each time telldir is called. It records the current magic * cookie returned by getdirentries and the offset within the buffer * associated with that return value. */ struct ddloc { struct ddloc *loc_next;/* next structure in list */ long loc_index; /* key associated with structure */ long loc_seek; /* magic cookie returned by getdirentries */ long loc_loc; /* offset of entry in buffer */ }; #define NDIRHASH 32 /* Num of hash lists, must be a power of 2 */ #define LOCHASH(i) ((i)&(NDIRHASH-1)) static long dd_loccnt; /* Index of entry for sequential readdir's */ static struct ddloc *dd_hash[NDIRHASH]; /* Hash list heads for ddlocs */ /* * return a pointer into a directory */ long telldir(dirp) const DIR *dirp; { register int index; register struct ddloc *lp; if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL) return (-1); index = dd_loccnt++; lp->loc_index = index; lp->loc_seek = dirp->dd_seek; lp->loc_loc = dirp->dd_loc; lp->loc_next = dd_hash[LOCHASH(index)]; dd_hash[LOCHASH(index)] = lp; return (index); } /* * seek to an entry in a directory. * Only values returned by "telldir" should be passed to seekdir. */ void _seekdir(dirp, loc) register DIR *dirp; long loc; { register struct ddloc *lp; register struct ddloc **prevlp; struct dirent *dp; prevlp = &dd_hash[LOCHASH(loc)]; lp = *prevlp; while (lp != NULL) { if (lp->loc_index == loc) break; prevlp = &lp->loc_next; lp = lp->loc_next; } if (lp == NULL) return; if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek) goto found; (void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET); dirp->dd_seek = lp->loc_seek; dirp->dd_loc = 0; while (dirp->dd_loc < lp->loc_loc) { dp = readdir(dirp); if (dp == NULL) break; } found: #ifdef SINGLEUSE *prevlp = lp->loc_next; free((caddr_t)lp); #endif }