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1d3fd5201c
Samba3 - with some 64-bit macro madness. Attempt to fix
the broken directory handling in the *BSD-of-the-month
club.
Jeremy.
(This used to be commit fd98427f64
)
219 lines
5.9 KiB
C
219 lines
5.9 KiB
C
/*
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Unix SMB/CIFS implementation.
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Copyright (C) Andrew Tridgell 2005
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Updated for Samba3 64-bit cleanliness (C) Jeremy Allison 2006
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/*
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a replacement for opendir/readdir/telldir/seekdir/closedir for BSD systems
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This is needed because the existing directory handling in FreeBSD
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and OpenBSD (and possibly NetBSD) doesn't correctly handle unlink()
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on files in a directory where telldir() has been used. On a block
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boundary it will occasionally miss a file when seekdir() is used to
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return to a position previously recorded with telldir().
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This also fixes a severe performance and memory usage problem with
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telldir() on BSD systems. Each call to telldir() in BSD adds an
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entry to a linked list, and those entries are cleaned up on
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closedir(). This means with a large directory closedir() can take an
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arbitrary amount of time, causing network timeouts as millions of
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telldir() entries are freed
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Note! This replacement code is not portable. It relies on getdents()
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always leaving the file descriptor at a seek offset that is a
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multiple of DIR_BUF_SIZE. If the code detects that this doesn't
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happen then it will abort(). It also does not handle directories
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with offsets larger than can be stored in a long,
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This code is available under other free software licenses as
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well. Contact the author.
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*/
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#include <include/includes.h>
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void replace_readdir_dummy(void);
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void replace_readdir_dummy(void) {}
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#if defined(REPLACE_READDIR)
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#if defined(PARANOID_MALLOC_CHECKER)
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#ifdef malloc
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#undef malloc
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#endif
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#endif
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#define DIR_BUF_BITS 9
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#define DIR_BUF_SIZE (1<<DIR_BUF_BITS)
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struct dir_buf {
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int fd;
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int nbytes, ofs;
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SMB_OFF_T seekpos;
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char buf[DIR_BUF_SIZE];
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};
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OPENDIR64)
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SMB_STRUCT_DIR *opendir64(const char *dname)
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#else
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SMB_STRUCT_DIR *opendir(const char *dname)
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#endif
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{
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struct dir_buf *d;
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d = malloc(sizeof(*d));
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if (d == NULL) {
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errno = ENOMEM;
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return NULL;
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}
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OPEN64)
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d->fd = open64(dname, O_RDONLY);
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#else
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d->fd = open(dname, O_RDONLY);
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#endif
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if (d->fd == -1) {
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free(d);
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return NULL;
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}
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d->ofs = 0;
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d->seekpos = 0;
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d->nbytes = 0;
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return (SMB_STRUCT_DIR *)d;
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}
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_READDIR64)
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SMB_STRUCT_DIRENT *readdir64(SMB_STRUCT_DIR *dir)
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#else
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SMB_STRUCT_DIRENT *readdir(SMB_STRUCT_DIR *dir)
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#endif
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{
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struct dir_buf *d = (struct dir_buf *)dir;
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SMB_STRUCT_DIRENT *de;
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if (d->ofs >= d->nbytes) {
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_LSEEK64)
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d->seekpos = lseek64(d->fd, 0, SEEK_CUR);
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#else
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d->seekpos = lseek(d->fd, 0, SEEK_CUR);
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#endif
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_GETDENTS64)
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d->nbytes = getdents64(d->fd, d->buf, DIR_BUF_SIZE);
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#else
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d->nbytes = getdents(d->fd, d->buf, DIR_BUF_SIZE);
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#endif
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d->ofs = 0;
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}
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if (d->ofs >= d->nbytes) {
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return NULL;
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}
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de = (SMB_STRUCT_DIRENT *)&d->buf[d->ofs];
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d->ofs += de->d_reclen;
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return de;
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}
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_TELLDIR64)
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long telldir64(SMB_STRUCT_DIR *dir)
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#else
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long telldir(SMB_STRUCT_DIR *dir)
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#endif
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{
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struct dir_buf *d = (struct dir_buf *)dir;
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if (d->ofs >= d->nbytes) {
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_LSEEK64)
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d->seekpos = lseek64(d->fd, 0, SEEK_CUR);
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#else
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d->seekpos = lseek(d->fd, 0, SEEK_CUR);
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#endif
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d->ofs = 0;
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d->nbytes = 0;
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}
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/* this relies on seekpos always being a multiple of
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DIR_BUF_SIZE. Is that always true on BSD systems? */
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if (d->seekpos & (DIR_BUF_SIZE-1)) {
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abort();
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}
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return d->seekpos + d->ofs;
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}
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_SEEKDIR64)
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void seekdir64(SMB_STRUCT_DIR *dir, long ofs)
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#else
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void seekdir(SMB_STRUCT_DIR *dir, long ofs)
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#endif
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{
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struct dir_buf *d = (struct dir_buf *)dir;
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_LSEEK64)
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d->seekpos = lseek64(d->fd, ofs & ~(DIR_BUF_SIZE-1), SEEK_SET);
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#else
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d->seekpos = lseek(d->fd, ofs & ~(DIR_BUF_SIZE-1), SEEK_SET);
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#endif
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_GETDENTS64)
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d->nbytes = getdents64(d->fd, d->buf, DIR_BUF_SIZE);
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#else
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d->nbytes = getdents(d->fd, d->buf, DIR_BUF_SIZE);
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#endif
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d->ofs = 0;
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while (d->ofs < (ofs & (DIR_BUF_SIZE-1))) {
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_READDIR64)
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if (readdir64(dir) == NULL) break;
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#else
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if (readdir(dir) == NULL) break;
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#endif
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}
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}
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_REWINDDIR64)
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void rewinddir64(SMB_STRUCT_DIR *dir)
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#else
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void rewinddir(SMB_STRUCT_DIR *dir)
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#endif
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{
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_SEEKDIR64)
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seekdir64(dir, 0);
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#else
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seekdir(dir, 0);
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#endif
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}
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#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_CLOSEDIR64)
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int closedir64(SMB_STRUCT_DIR *dir)
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#else
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int closedir(SMB_STRUCT_DIR *dir)
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#endif
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{
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struct dir_buf *d = (struct dir_buf *)dir;
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int r = close(d->fd);
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if (r != 0) {
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return r;
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}
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free(d);
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return 0;
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}
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#ifndef dirfd
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/* darn, this is a macro on some systems. */
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int dirfd(SMB_STRUCT_DIR *dir)
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{
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struct dir_buf *d = (struct dir_buf *)dir;
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return d->fd;
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}
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#endif
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#endif /* REPLACE_READDIR */
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