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544 lines
12 KiB
C
544 lines
12 KiB
C
/* Copyright (C) 1991-2015 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* Wants:
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AC_STDC_HEADERS
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AC_DIR_HEADER
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AC_UNISTD_H
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AC_MEMORY_H
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AC_CONST
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AC_ALLOCA
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*/
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/* AIX requires this to be the first thing in the file. */
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#if defined _AIX && !defined __GNUC__
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#pragma alloca
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#endif
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#ifdef STDC_HEADERS
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# include <stddef.h>
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#endif
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#if !defined __GNU_LIBRARY__ && !defined STDC_HEADERS
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extern int errno;
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#endif
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#ifndef __set_errno
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# define __set_errno(val) errno = (val)
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#endif
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#ifndef NULL
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# define NULL 0
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#endif
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#if defined USGr3 && !defined DIRENT
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# define DIRENT
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#endif /* USGr3 */
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#if defined Xenix && !defined SYSNDIR
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# define SYSNDIR
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#endif /* Xenix */
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#if defined POSIX || defined DIRENT || defined __GNU_LIBRARY__
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# include <dirent.h>
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# ifndef __GNU_LIBRARY__
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# define D_NAMLEN(d) strlen((d)->d_name)
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# else
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# define HAVE_D_NAMLEN
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# define D_NAMLEN(d) ((d)->d_namlen)
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# endif
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#else /* not POSIX or DIRENT */
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# define dirent direct
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# define D_NAMLEN(d) ((d)->d_namlen)
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# define HAVE_D_NAMLEN
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# if defined USG && !defined sgi
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# if defined SYSNDIR
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# include <sys/ndir.h>
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# else /* Not SYSNDIR */
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# include "ndir.h"
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# endif /* SYSNDIR */
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# else /* not USG */
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# include <sys/dir.h>
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# endif /* USG */
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#endif /* POSIX or DIRENT or __GNU_LIBRARY__ */
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#if defined HAVE_UNISTD_H || defined __GNU_LIBRARY__
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# include <unistd.h>
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#endif
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#if defined STDC_HEADERS || defined __GNU_LIBRARY__ || defined POSIX
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# include <stdlib.h>
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# include <string.h>
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# define ANSI_STRING
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#else /* No standard headers. */
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# ifdef USG
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# include <string.h>
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# ifdef NEED_MEMORY_H
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# include <memory.h>
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# endif
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# define ANSI_STRING
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# else /* Not USG. */
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# ifdef NeXT
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# include <string.h>
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# else /* Not NeXT. */
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# include <strings.h>
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# ifndef bcmp
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extern int bcmp ();
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# endif
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# ifndef bzero
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extern void bzero ();
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# endif
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# ifndef bcopy
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extern void bcopy ();
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# endif
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# endif /* NeXT. */
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# endif /* USG. */
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extern char *malloc (), *realloc ();
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extern void free ();
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#endif /* Standard headers. */
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#ifndef ANSI_STRING
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# define memcpy(d, s, n) bcopy((s), (d), (n))
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# define memmove memcpy
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#endif /* Not ANSI_STRING. */
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#ifndef MAX
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# define MAX(a, b) ((a) < (b) ? (b) : (a))
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#endif
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#ifdef _LIBC
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# ifndef mempcpy
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# define mempcpy __mempcpy
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# endif
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# define HAVE_MEMPCPY 1
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#endif
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#if !defined __alloca && !defined __GNU_LIBRARY__
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# ifdef __GNUC__
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# undef alloca
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# define alloca(n) __builtin_alloca (n)
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# else /* Not GCC. */
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# if defined sparc || defined HAVE_ALLOCA_H
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# include <alloca.h>
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# else /* Not sparc or HAVE_ALLOCA_H. */
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# ifndef _AIX
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extern char *alloca ();
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# endif /* Not _AIX. */
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# endif /* sparc or HAVE_ALLOCA_H. */
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# endif /* GCC. */
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# define __alloca alloca
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#endif
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#if defined HAVE_LIMITS_H || defined STDC_HEADERS || defined __GNU_LIBRARY__
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# include <limits.h>
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#else
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# include <sys/param.h>
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#endif
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#if defined _LIBC
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# include <not-cancel.h>
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# include <kernel-features.h>
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#else
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# define openat64_not_cancel_3(dfd, name, mode) openat64 (dfd, name, mode)
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# define close_not_cancel_no_status(fd) close (fd)
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#endif
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#ifndef PATH_MAX
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# ifdef MAXPATHLEN
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# define PATH_MAX MAXPATHLEN
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# else
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# define PATH_MAX 1024
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# endif
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#endif
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#if !defined STDC_HEADERS && !defined __GNU_LIBRARY__
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# undef size_t
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# define size_t unsigned int
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#endif
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#ifndef __GNU_LIBRARY__
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# define __lstat64 stat64
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#endif
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#ifndef _LIBC
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# define __rewinddir rewinddir
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#endif
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#ifndef _LIBC
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# define __getcwd getcwd
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#endif
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#ifndef GETCWD_RETURN_TYPE
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# define GETCWD_RETURN_TYPE char *
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#endif
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#ifdef __ASSUME_ATFCTS
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# define __have_atfcts 1
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#elif IS_IN (rtld)
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static int __rtld_have_atfcts;
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# define __have_atfcts __rtld_have_atfcts
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#endif
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/* Get the pathname of the current working directory, and put it in SIZE
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bytes of BUF. Returns NULL if the directory couldn't be determined or
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SIZE was too small. If successful, returns BUF. In GNU, if BUF is
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NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
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unless SIZE == 0, in which case it is as big as necessary. */
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GETCWD_RETURN_TYPE
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__getcwd (buf, size)
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char *buf;
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size_t size;
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{
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#ifndef __ASSUME_ATFCTS
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static const char dots[]
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= "../../../../../../../../../../../../../../../../../../../../../../../\
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../../../../../../../../../../../../../../../../../../../../../../../../../../\
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../../../../../../../../../../../../../../../../../../../../../../../../../..";
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const char *dotp = &dots[sizeof (dots)];
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const char *dotlist = dots;
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size_t dotsize = sizeof (dots) - 1;
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#endif
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int prev_errno = errno;
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DIR *dirstream = NULL;
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bool fd_needs_closing = false;
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int fd = AT_FDCWD;
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char *path;
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#ifndef NO_ALLOCATION
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size_t allocated = size;
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if (size == 0)
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{
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if (buf != NULL)
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{
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__set_errno (EINVAL);
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return NULL;
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}
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allocated = PATH_MAX + 1;
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}
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if (buf == NULL)
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{
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path = malloc (allocated);
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if (path == NULL)
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return NULL;
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}
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else
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#else
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# define allocated size
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#endif
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path = buf;
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char *pathp = path + allocated;
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*--pathp = '\0';
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struct stat64 st;
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if (__lstat64 (".", &st) < 0)
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goto lose;
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dev_t thisdev = st.st_dev;
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ino_t thisino = st.st_ino;
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if (__lstat64 ("/", &st) < 0)
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goto lose;
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dev_t rootdev = st.st_dev;
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ino_t rootino = st.st_ino;
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while (!(thisdev == rootdev && thisino == rootino))
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{
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if (__have_atfcts >= 0)
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{
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int mode = O_RDONLY;
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#ifdef O_CLOEXEC
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mode |= O_CLOEXEC;
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#endif
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fd = openat64_not_cancel_3 (fd, "..", mode);
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}
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else
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fd = -1;
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if (fd >= 0)
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{
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fd_needs_closing = true;
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if (__fstat64 (fd, &st) < 0)
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goto lose;
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}
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#ifndef __ASSUME_ATFCTS
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else if (errno == ENOSYS)
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{
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__have_atfcts = -1;
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/* Look at the parent directory. */
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if (dotp == dotlist)
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{
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# ifdef NO_ALLOCATION
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__set_errno (ENOMEM);
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goto lose;
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# else
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/* My, what a deep directory tree you have, Grandma. */
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char *new;
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if (dotlist == dots)
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{
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new = malloc (dotsize * 2 + 1);
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if (new == NULL)
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goto lose;
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# ifdef HAVE_MEMPCPY
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dotp = mempcpy (new, dots, dotsize);
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# else
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memcpy (new, dots, dotsize);
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dotp = &new[dotsize];
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# endif
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}
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else
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{
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new = realloc ((__ptr_t) dotlist, dotsize * 2 + 1);
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if (new == NULL)
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goto lose;
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dotp = &new[dotsize];
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}
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# ifdef HAVE_MEMPCPY
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*((char *) mempcpy ((char *) dotp, new, dotsize)) = '\0';
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dotsize *= 2;
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# else
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memcpy ((char *) dotp, new, dotsize);
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dotsize *= 2;
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new[dotsize] = '\0';
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# endif
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dotlist = new;
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# endif
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}
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dotp -= 3;
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/* Figure out if this directory is a mount point. */
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if (__lstat64 (dotp, &st) < 0)
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goto lose;
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}
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#endif
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else
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goto lose;
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if (dirstream && __closedir (dirstream) != 0)
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{
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dirstream = NULL;
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goto lose;
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}
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dev_t dotdev = st.st_dev;
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ino_t dotino = st.st_ino;
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bool mount_point = dotdev != thisdev;
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/* Search for the last directory. */
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if (__have_atfcts >= 0)
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dirstream = __fdopendir (fd);
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#ifndef __ASSUME_ATFCTS
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else
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dirstream = __opendir (dotp);
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#endif
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if (dirstream == NULL)
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goto lose;
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fd_needs_closing = false;
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struct dirent *d;
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bool use_d_ino = true;
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while (1)
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{
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/* Clear errno to distinguish EOF from error if readdir returns
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NULL. */
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__set_errno (0);
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d = __readdir (dirstream);
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if (d == NULL)
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{
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if (errno == 0)
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{
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/* When we've iterated through all directory entries
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without finding one with a matching d_ino, rewind the
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stream and consider each name again, but this time, using
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lstat64. This is necessary in a chroot on at least one
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system. */
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if (use_d_ino)
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{
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use_d_ino = false;
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__rewinddir (dirstream);
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continue;
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}
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/* EOF on dirstream, which means that the current directory
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has been removed. */
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__set_errno (ENOENT);
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}
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goto lose;
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}
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#ifdef _DIRENT_HAVE_D_TYPE
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if (d->d_type != DT_DIR && d->d_type != DT_UNKNOWN)
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continue;
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#endif
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if (d->d_name[0] == '.'
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&& (d->d_name[1] == '\0'
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|| (d->d_name[1] == '.' && d->d_name[2] == '\0')))
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continue;
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if (use_d_ino && !mount_point && (ino_t) d->d_ino != thisino)
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continue;
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if (__have_atfcts >= 0)
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{
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/* We don't fail here if we cannot stat64() a directory entry.
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This can happen when (network) filesystems fail. If this
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entry is in fact the one we are looking for we will find
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out soon as we reach the end of the directory without
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having found anything. */
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if (__fstatat64 (fd, d->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0)
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continue;
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}
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#ifndef __ASSUME_ATFCTS
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else
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{
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char name[dotlist + dotsize - dotp + 1 + _D_ALLOC_NAMLEN (d)];
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# ifdef HAVE_MEMPCPY
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char *tmp = mempcpy (name, dotp, dotlist + dotsize - dotp);
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*tmp++ = '/';
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strcpy (tmp, d->d_name);
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# else
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memcpy (name, dotp, dotlist + dotsize - dotp);
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name[dotlist + dotsize - dotp] = '/';
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strcpy (&name[dotlist + dotsize - dotp + 1], d->d_name);
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# endif
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/* We don't fail here if we cannot stat64() a directory entry.
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This can happen when (network) filesystems fail. If this
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entry is in fact the one we are looking for we will find
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out soon as we reach the end of the directory without
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having found anything. */
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if (__lstat64 (name, &st) < 0)
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continue;
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}
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#endif
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if (S_ISDIR (st.st_mode)
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&& st.st_dev == thisdev && st.st_ino == thisino)
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break;
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}
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size_t namlen = _D_EXACT_NAMLEN (d);
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if ((size_t) (pathp - path) <= namlen)
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{
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#ifndef NO_ALLOCATION
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if (size == 0)
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{
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size_t oldsize = allocated;
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allocated = 2 * MAX (allocated, namlen);
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char *tmp = realloc (path, allocated);
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if (tmp == NULL)
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goto lose;
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/* Move current contents up to the end of the buffer.
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This is guaranteed to be non-overlapping. */
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pathp = memcpy (tmp + allocated - (path + oldsize - pathp),
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tmp + (pathp - path),
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path + oldsize - pathp);
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path = tmp;
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}
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else
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#endif
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{
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__set_errno (ERANGE);
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goto lose;
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}
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}
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pathp -= namlen;
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(void) memcpy (pathp, d->d_name, namlen);
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*--pathp = '/';
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thisdev = dotdev;
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thisino = dotino;
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}
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if (dirstream != NULL && __closedir (dirstream) != 0)
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{
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dirstream = NULL;
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goto lose;
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}
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if (pathp == &path[allocated - 1])
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*--pathp = '/';
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#ifndef __ASSUME_ATFCTS
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if (dotlist != dots)
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free ((__ptr_t) dotlist);
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#endif
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size_t used = path + allocated - pathp;
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memmove (path, pathp, used);
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if (size == 0)
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/* Ensure that the buffer is only as large as necessary. */
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buf = realloc (path, used);
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if (buf == NULL)
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/* Either buf was NULL all along, or `realloc' failed but
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we still have the original string. */
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buf = path;
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/* Restore errno on successful return. */
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__set_errno (prev_errno);
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return buf;
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lose:;
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int save_errno = errno;
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#ifndef __ASSUME_ATFCTS
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if (dotlist != dots)
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free ((__ptr_t) dotlist);
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#endif
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if (dirstream != NULL)
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__closedir (dirstream);
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if (fd_needs_closing)
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close_not_cancel_no_status (fd);
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#ifndef NO_ALLOCATION
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if (buf == NULL)
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free (path);
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#endif
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__set_errno (save_errno);
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return NULL;
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}
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#if defined _LIBC && !defined __getcwd
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weak_alias (__getcwd, getcwd)
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#endif
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