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/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
*
* Copyright (c) 2000
* Daniel Eischen. 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. 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.
*
* $FreeBSD$
*/
#ifndef _TELLDIR_H_
#define _TELLDIR_H_
#include <sys/queue.h>
#include <stdbool.h>
/*
* telldir will malloc one of these to describe the current directory position,
* if it can't fit that information into the packed structure below. It
* records the current magic cookie returned by getdirentries and the offset
* within the buffer associated with that return value.
*/
struct ddloc_mem {
LIST_ENTRY(ddloc_mem) loc_lqe; /* entry 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 */
};
#ifdef __LP64__
#define DD_LOC_BITS 31
#define DD_SEEK_BITS 32
#define DD_INDEX_BITS 63
#else
#define DD_LOC_BITS 12
#define DD_SEEK_BITS 19
#define DD_INDEX_BITS 31
#endif
/*
* This is the real type returned by telldir. telldir will prefer to return
* the packed type, if possible, or the malloced type otherwise. For msdosfs,
* UFS, and NFS, directory positions usually fit within the packed type. For
* ZFS and tmpfs, they usually fit within the packed type on 64-bit
* architectures.
*/
union ddloc_packed {
long l; /* Opaque type returned by telldir(3) */
struct {
/* Identifies union type. Must be 0. */
unsigned long is_packed:1;
/* Index into directory's linked list of ddloc_mem */
unsigned long index:DD_INDEX_BITS;
} __packed i;
struct {
/* Identifies union type. Must be 1. */
unsigned long is_packed:1;
/* offset of entry in buffer*/
unsigned long loc:DD_LOC_BITS;
/* magic cookie returned by getdirentries */
unsigned long seek:DD_SEEK_BITS;
} __packed s;
};
_Static_assert(sizeof(long) == sizeof(union ddloc_packed),
"packed telldir size mismatch!");
/*
* One of these structures is malloced for each DIR to record telldir
* positions.
*/
struct _telldir {
LIST_HEAD(, ddloc_mem) td_locq; /* list of locations */
long td_loccnt; /* index of entry for sequential readdir's */
};
bool _filldir(DIR *, bool);
struct dirent *_readdir_unlocked(DIR *, int);
void _reclaim_telldir(DIR *);
void _seekdir(DIR *, long);
void _fixtelldir(DIR *dirp, long oldseek, long oldloc);
#endif
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