1 /* Read a directory. Linux LFS version.
2 Copyright (C) 1997-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 /* When _DIRENT_MATCHES_DIRENT64 is defined we can alias 'readdir64' to
20 'readdir'. However the function signatures are not equal due
21 different return types, so we need to suppress {__}readdir so weak
22 and strong alias do not throw conflicting types errors. */
23 #define readdir __no_readdir_decl
24 #define __readdir __no___readdir_decl
25 #include <dirent.h>
26 #undef __readdir
27 #undef readdir
28
29 /* Read a directory entry from DIRP. */
30 struct dirent64 *
__readdir64(DIR * dirp)31 __readdir64 (DIR *dirp)
32 {
33 struct dirent64 *dp;
34 int saved_errno = errno;
35
36 #if IS_IN (libc)
37 __libc_lock_lock (dirp->lock);
38 #endif
39
40 do
41 {
42 size_t reclen;
43
44 if (dirp->offset >= dirp->size)
45 {
46 /* We've emptied out our buffer. Refill it. */
47
48 size_t maxread = dirp->allocation;
49 ssize_t bytes;
50
51 bytes = __getdents64 (dirp->fd, dirp->data, maxread);
52 if (bytes <= 0)
53 {
54 /* On some systems getdents fails with ENOENT when the
55 open directory has been rmdir'd already. POSIX.1
56 requires that we treat this condition like normal EOF. */
57 if (bytes < 0 && errno == ENOENT)
58 bytes = 0;
59
60 /* Don't modifiy errno when reaching EOF. */
61 if (bytes == 0)
62 __set_errno (saved_errno);
63 dp = NULL;
64 break;
65 }
66 dirp->size = (size_t) bytes;
67
68 /* Reset the offset into the buffer. */
69 dirp->offset = 0;
70 }
71
72 dp = (struct dirent64 *) &dirp->data[dirp->offset];
73
74 reclen = dp->d_reclen;
75
76 dirp->offset += reclen;
77
78 dirp->filepos = dp->d_off;
79
80 /* Skip deleted files. */
81 } while (dp->d_ino == 0);
82
83 #if IS_IN (libc)
84 __libc_lock_unlock (dirp->lock);
85 #endif
86
87 return dp;
88 }
89 libc_hidden_def (__readdir64)
90
91 #if _DIRENT_MATCHES_DIRENT64
92 strong_alias (__readdir64, __readdir)
93 weak_alias (__readdir64, readdir64)
94 weak_alias (__readdir64, readdir)
95 #else
96 /* The compat code expects the 'struct direct' with d_ino being a __ino_t
97 instead of __ino64_t. */
98 # include <shlib-compat.h>
99 # if IS_IN(rtld)
100 weak_alias (__readdir64, readdir64)
101 # else
102 versioned_symbol (libc, __readdir64, readdir64, GLIBC_2_2);
103 # endif
104 # if SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_2)
105 # include <olddirent.h>
106
107 attribute_compat_text_section
108 struct __old_dirent64 *
109 __old_readdir64 (DIR *dirp)
110 {
111 struct __old_dirent64 *dp;
112 int saved_errno = errno;
113
114 #if IS_IN (libc)
115 __libc_lock_lock (dirp->lock);
116 #endif
117
118 do
119 {
120 size_t reclen;
121
122 if (dirp->offset >= dirp->size)
123 {
124 /* We've emptied out our buffer. Refill it. */
125
126 size_t maxread = dirp->allocation;
127 ssize_t bytes;
128
129 bytes = __old_getdents64 (dirp->fd, dirp->data, maxread);
130 if (bytes <= 0)
131 {
132 /* On some systems getdents fails with ENOENT when the
133 open directory has been rmdir'd already. POSIX.1
134 requires that we treat this condition like normal EOF. */
135 if (bytes < 0 && errno == ENOENT)
136 bytes = 0;
137
138 /* Don't modifiy errno when reaching EOF. */
139 if (bytes == 0)
140 __set_errno (saved_errno);
141 dp = NULL;
142 break;
143 }
144 dirp->size = (size_t) bytes;
145
146 /* Reset the offset into the buffer. */
147 dirp->offset = 0;
148 }
149
150 dp = (struct __old_dirent64 *) &dirp->data[dirp->offset];
151
152 reclen = dp->d_reclen;
153
154 dirp->offset += reclen;
155
156 dirp->filepos = dp->d_off;
157
158 /* Skip deleted files. */
159 } while (dp->d_ino == 0);
160
161 #if IS_IN (libc)
162 __libc_lock_unlock (dirp->lock);
163 #endif
164
165 return dp;
166 }
167 libc_hidden_def (__old_readdir64)
168 compat_symbol (libc, __old_readdir64, readdir64, GLIBC_2_1);
169 # endif /* SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_2) */
170 #endif /* _DIRENT_MATCHES_DIRENT64 */
171