67 lines
2.2 KiB
C
67 lines
2.2 KiB
C
/* Copyright (C) 1993-2022 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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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <stddef.h>
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#include <dirent.h>
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#include <unistd.h>
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#include <endian.h>
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#include <assert.h>
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/* Read a directory entry from DIRP. */
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struct dirent *
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__readdir (DIR *dirp)
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{
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struct dirent64 *entry64 = __readdir64 (dirp);
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if (sizeof (struct dirent64) == sizeof (struct dirent))
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/* We should in fact just be an alias to readdir64 on this machine. */
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return (struct dirent *) entry64;
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/* These are all compile-time constants. We know that d_ino is the first
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member and that the layout of the following members matches exactly in
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both structures. */
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assert (offsetof (struct dirent, d_ino) == 0);
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assert (offsetof (struct dirent64, d_ino) == 0);
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# define MATCH(memb) \
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assert (offsetof (struct dirent64, memb) - sizeof (entry64->d_ino) \
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== offsetof (struct dirent, memb) - sizeof (ino_t))
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MATCH (d_reclen);
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MATCH (d_type);
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MATCH (d_namlen);
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# undef MATCH
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if (entry64 == NULL)
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return NULL;
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struct dirent *const entry = ((void *) (&entry64->d_ino + 1)
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- sizeof entry->d_ino);
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const ino_t d_ino = entry64->d_ino;
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if (d_ino != entry64->d_ino)
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{
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__set_errno (EOVERFLOW);
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return NULL;
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}
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# if BYTE_ORDER != BIG_ENDIAN /* We just skipped over the zero high word. */
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entry->d_ino = d_ino; /* ... or the nonzero low word, swap it. */
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# endif
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entry->d_reclen -= sizeof entry64->d_ino - sizeof entry->d_ino;
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return entry;
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}
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weak_alias (__readdir, readdir)
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