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[glibc.git] / sysdeps / unix / readdir.c
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1 /* Copyright (C) 1991, 92, 93, 94, 95, 96, 97 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
19 #include <errno.h>
20 #include <limits.h>
21 #include <stddef.h>
22 #include <string.h>
23 #include <dirent.h>
24 #include <unistd.h>
25 #include <sys/types.h>
26 #include <assert.h>
28 #include <dirstream.h>
31 /* Read a directory entry from DIRP. */
32 struct dirent *
33 __readdir (DIR *dirp)
35 struct dirent *dp;
37 __libc_lock_lock (dirp->lock);
41 size_t reclen;
43 if (dirp->offset >= dirp->size)
45 /* We've emptied out our buffer. Refill it. */
47 size_t maxread;
48 off_t base;
49 ssize_t bytes;
51 #ifndef _DIRENT_HAVE_D_RECLEN
52 /* Fixed-size struct; must read one at a time (see below). */
53 maxread = sizeof *dp;
54 #else
55 maxread = dirp->allocation;
56 #endif
58 base = dirp->filepos;
59 bytes = __getdirentries (dirp->fd, dirp->data, maxread, &base);
60 if (bytes <= 0)
62 dp = NULL;
63 break;
65 dirp->size = (size_t) bytes;
67 /* Reset the offset into the buffer. */
68 dirp->offset = 0;
71 dp = (struct dirent *) &dirp->data[dirp->offset];
73 #ifdef _DIRENT_HAVE_D_RECLEN
74 reclen = dp->d_reclen;
75 #else
76 /* The only version of `struct dirent' that lacks `d_reclen'
77 is fixed-size. */
78 assert (sizeof dp->d_name > 1);
79 reclen = sizeof *dp;
80 /* The name is not terminated if it is the largest possible size.
81 Clobber the following byte to ensure proper null termination. We
82 read jst one entry at a time above so we know that byte will not
83 be used later. */
84 dp->d_name[sizeof dp->d_name] = '\0';
85 #endif
87 dirp->offset += reclen;
89 #ifdef _DIRENT_HAVE_D_OFF
90 dirp->filepos = dp->d_off;
91 #else
92 dirp->filepos += reclen;
93 #endif
95 /* Skip deleted files. */
96 } while (dp->d_ino == 0);
98 __libc_lock_unlock (dirp->lock);
100 return dp;
102 weak_alias (__readdir, readdir)