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Diffstat (limited to 'lib/libc/gen/telldir.h')
| -rw-r--r-- | lib/libc/gen/telldir.h | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/lib/libc/gen/telldir.h b/lib/libc/gen/telldir.h new file mode 100644 index 000000000000..02fd52af9060 --- /dev/null +++ b/lib/libc/gen/telldir.h @@ -0,0 +1,111 @@ +/*- + * SPDX-License-Identifier: BSD-3-Clause + * + * 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. + */ + +#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 */ + size_t loc_index; /* key associated with structure */ + off_t loc_seek; /* magic cookie returned by getdirentries */ + size_t 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, off_t oldseek, size_t oldloc); +DIR *__opendir_common(int, int, bool); + +#define RDU_SKIP 0x0001 +#define RDU_SHORT 0x0002 + +#endif |