1/* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Copyright (c) 2000 6 * Daniel Eischen. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * $FreeBSD: stable/11/lib/libc/gen/telldir.h 327850 2018-01-11 23:57:55Z asomers $ 33 */ 34 35#ifndef _TELLDIR_H_ 36#define _TELLDIR_H_ 37 38#include <sys/queue.h> 39#include <stdbool.h> 40 41/* 42 * telldir will malloc one of these to describe the current directory position, 43 * if it can't fit that information into the packed structure below. It 44 * records the current magic cookie returned by getdirentries and the offset 45 * within the buffer associated with that return value. 46 */ 47struct ddloc_mem { 48 LIST_ENTRY(ddloc_mem) loc_lqe; /* entry in list */ 49 long loc_index; /* key associated with structure */ 50 long loc_seek; /* magic cookie returned by getdirentries */ 51 long loc_loc; /* offset of entry in buffer */ 52}; 53 54#ifdef __LP64__ 55#define DD_LOC_BITS 31 56#define DD_SEEK_BITS 32 57#define DD_INDEX_BITS 63 58#else 59#define DD_LOC_BITS 12 60#define DD_SEEK_BITS 19 61#define DD_INDEX_BITS 31 62#endif 63 64/* 65 * This is the real type returned by telldir. telldir will prefer to return 66 * the packed type, if possible, or the malloced type otherwise. For msdosfs, 67 * UFS, and NFS, directory positions usually fit within the packed type. For 68 * ZFS and tmpfs, they usually fit within the packed type on 64-bit 69 * architectures. 70 */ 71union ddloc_packed { 72 long l; /* Opaque type returned by telldir(3) */ 73 struct { 74 /* Identifies union type. Must be 0. */ 75 unsigned long is_packed:1; 76 /* Index into directory's linked list of ddloc_mem */ 77 unsigned long index:DD_INDEX_BITS; 78 } __packed i; 79 struct { 80 /* Identifies union type. Must be 1. */ 81 unsigned long is_packed:1; 82 /* offset of entry in buffer*/ 83 unsigned long loc:DD_LOC_BITS; 84 /* magic cookie returned by getdirentries */ 85 unsigned long seek:DD_SEEK_BITS; 86 } __packed s; 87}; 88 89_Static_assert(sizeof(long) == sizeof(union ddloc_packed), 90 "packed telldir size mismatch!"); 91 92/* 93 * One of these structures is malloced for each DIR to record telldir 94 * positions. 95 */ 96struct _telldir { 97 LIST_HEAD(, ddloc_mem) td_locq; /* list of locations */ 98 long td_loccnt; /* index of entry for sequential readdir's */ 99}; 100 101bool _filldir(DIR *, bool); 102struct dirent *_readdir_unlocked(DIR *, int); 103void _reclaim_telldir(DIR *); 104void _seekdir(DIR *, long); 105void _fixtelldir(DIR *dirp, long oldseek, long oldloc); 106 107#endif 108