freebsd-skq/include/dirent.h
jhb cabf1ab5da MFC 268531,269079,269204:
Fix various edge cases with rewinddir(), seekdir(), and telldir():
- In the unionfs case, opendir() and fdopendir() read the directory's full
  contents and cache it.  This cache is not refreshed when rewinddir() is
  called, so rewinddir() will not notice updates to a directory.  Fix this
  by splitting the code to fetch a directory's contents out of
  __opendir_common() into a new _filldir() function and call this from
  rewinddir() when operating on a unionfs directory.
- If rewinddir() is called on a directory opened with fdopendir() before
  any directory entries are fetched, rewinddir() will not adjust the seek
  location of the backing file descriptor.  If the file descriptor passed
  to fdopendir() had a non-zero offset, the rewinddir() will not rewind to
  the beginning.  Fix this by always seeking back to 0 in rewinddir().
  This means the dd_rewind hack can also be removed.
- Add missing locking to rewinddir()
- POSIX says that passing a location returned by telldir() to seekdir()
  after an intervening call to rewinddir() is undefined, so reclaim any
  pending telldir() cookies in the directory when rewinddir() is called.
- If telldir() is called immediately after a call to seekdir(), POSIX
  requires the return value of telldir() to equal the value passed to
  seekdir().  The current seekdir code with SINGLEUSE enabled breaks
  this case as each call to telldir() allocates a new cookie.  Instead,
  remove the SINGLEUSE code and change telldir() to look for an existing
  cookie for the directory's current location rather than always creating
  a new cookie.

PR:		121656
2014-08-14 20:20:21 +00:00

110 lines
3.5 KiB
C

/*-
* Copyright (c) 1989, 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. 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.
*
* @(#)dirent.h 8.2 (Berkeley) 7/28/94
* $FreeBSD$
*/
#ifndef _DIRENT_H_
#define _DIRENT_H_
/*
* The kernel defines the format of directory entries returned by
* the getdirentries(2) system call.
*/
#include <sys/cdefs.h>
#include <sys/dirent.h>
#if __BSD_VISIBLE || __XSI_VISIBLE
/*
* XXX this is probably illegal in the __XSI_VISIBLE case, but brings us closer
* to the specification.
*/
#define d_ino d_fileno /* backward and XSI compatibility */
#endif
#if __BSD_VISIBLE
#include <sys/_null.h>
/* definitions for library routines operating on directories. */
#define DIRBLKSIZ 1024
struct _dirdesc;
typedef struct _dirdesc DIR;
/* flags for opendir2 */
#define DTF_HIDEW 0x0001 /* hide whiteout entries */
#define DTF_NODUP 0x0002 /* don't return duplicate names */
#define DTF_REWIND 0x0004 /* rewind after reading union stack */
#define __DTF_READALL 0x0008 /* everything has been read */
#define __DTF_SKIPREAD 0x0010 /* assume internal buffer is populated */
#else /* !__BSD_VISIBLE */
typedef void * DIR;
#endif /* __BSD_VISIBLE */
#ifndef _KERNEL
__BEGIN_DECLS
#if __POSIX_VISIBLE >= 200809 || __XSI_VISIBLE >= 700
int alphasort(const struct dirent **, const struct dirent **);
int dirfd(DIR *);
#endif
#if __BSD_VISIBLE
DIR *__opendir2(const char *, int);
int fdclosedir(DIR *);
int getdents(int, char *, int);
int getdirentries(int, char *, int, long *);
#endif
DIR *opendir(const char *);
DIR *fdopendir(int);
struct dirent *
readdir(DIR *);
#if __POSIX_VISIBLE >= 199506 || __XSI_VISIBLE >= 500
int readdir_r(DIR *, struct dirent *, struct dirent **);
#endif
void rewinddir(DIR *);
#if __POSIX_VISIBLE >= 200809 || __XSI_VISIBLE >= 700
int scandir(const char *, struct dirent ***,
int (*)(const struct dirent *), int (*)(const struct dirent **,
const struct dirent **));
#endif
#if __XSI_VISIBLE
void seekdir(DIR *, long);
long telldir(DIR *);
#endif
int closedir(DIR *);
__END_DECLS
#endif /* !_KERNEL */
#endif /* !_DIRENT_H_ */