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111 lines
3.8 KiB
C
111 lines
3.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Copyright (c) 2000
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* Daniel Eischen. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _TELLDIR_H_
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#define _TELLDIR_H_
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#include <sys/queue.h>
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#include <stdbool.h>
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/*
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* telldir will malloc one of these to describe the current directory position,
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* if it can't fit that information into the packed structure below. It
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* records the current magic cookie returned by getdirentries and the offset
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* within the buffer associated with that return value.
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*/
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struct ddloc_mem {
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LIST_ENTRY(ddloc_mem) loc_lqe; /* entry in list */
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long loc_index; /* key associated with structure */
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off_t loc_seek; /* magic cookie returned by getdirentries */
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long loc_loc; /* offset of entry in buffer */
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};
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#ifdef __LP64__
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#define DD_LOC_BITS 31
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#define DD_SEEK_BITS 32
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#define DD_INDEX_BITS 63
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#else
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#define DD_LOC_BITS 12
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#define DD_SEEK_BITS 19
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#define DD_INDEX_BITS 31
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#endif
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/*
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* This is the real type returned by telldir. telldir will prefer to return
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* the packed type, if possible, or the malloced type otherwise. For msdosfs,
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* UFS, and NFS, directory positions usually fit within the packed type. For
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* ZFS and tmpfs, they usually fit within the packed type on 64-bit
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* architectures.
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*/
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union ddloc_packed {
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long l; /* Opaque type returned by telldir(3) */
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struct {
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/* Identifies union type. Must be 0. */
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unsigned long is_packed:1;
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/* Index into directory's linked list of ddloc_mem */
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unsigned long index:DD_INDEX_BITS;
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} __packed i;
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struct {
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/* Identifies union type. Must be 1. */
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unsigned long is_packed:1;
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/* offset of entry in buffer*/
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unsigned long loc:DD_LOC_BITS;
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/* magic cookie returned by getdirentries */
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unsigned long seek:DD_SEEK_BITS;
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} __packed s;
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};
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_Static_assert(sizeof(long) == sizeof(union ddloc_packed),
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"packed telldir size mismatch!");
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/*
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* One of these structures is malloced for each DIR to record telldir
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* positions.
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*/
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struct _telldir {
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LIST_HEAD(, ddloc_mem) td_locq; /* list of locations */
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long td_loccnt; /* index of entry for sequential readdir's */
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};
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bool _filldir(DIR *, bool);
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struct dirent *_readdir_unlocked(DIR *, int);
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void _reclaim_telldir(DIR *);
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void _seekdir(DIR *, long);
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void _fixtelldir(DIR *dirp, long oldseek, long oldloc);
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#define RDU_SKIP 0x0001
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#define RDU_SHORT 0x0002
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#endif
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