1 /* Copyright (C) 1991-2024 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 Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the 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 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
21 #include <stdio.h> /* For BUFSIZ. */
22 #include <sys/param.h> /* For MIN and MAX. */
24 #include <not-cancel.h>
27 opendir_oflags
= O_RDONLY
|O_NDELAY
|O_DIRECTORY
|O_LARGEFILE
|O_CLOEXEC
31 invalid_name (const char *name
)
33 if (__glibc_unlikely (name
[0] == '\0'))
35 /* POSIX.1-1990 says an empty name gets ENOENT;
36 but `open' might like it fine. */
46 if (__glibc_unlikely (fd
< 0))
49 /* Now make sure this really is a directory and nothing changed since the
50 `stat' call. The S_ISDIR check is superfluous if O_DIRECTORY works,
51 but it's cheap and we need the stat call for st_blksize anyway. */
52 struct __stat64_t64 statbuf
;
53 if (__glibc_unlikely (__fstat64_time64 (fd
, &statbuf
) < 0))
55 if (__glibc_unlikely (! S_ISDIR (statbuf
.st_mode
)))
57 __set_errno (ENOTDIR
);
59 __close_nocancel_nostatus (fd
);
63 return __alloc_dir (fd
, true, 0, &statbuf
);
69 __opendirat (int dfd
, const char *name
)
71 if (__glibc_unlikely (invalid_name (name
)))
74 return opendir_tail (__openat_nocancel (dfd
, name
, opendir_oflags
));
79 /* Open a directory stream on NAME. */
81 __opendir (const char *name
)
83 if (__glibc_unlikely (invalid_name (name
)))
86 return opendir_tail (__open_nocancel (name
, opendir_oflags
));
88 weak_alias (__opendir
, opendir
)
91 __alloc_dir (int fd
, bool close_fd
, int flags
,
92 const struct __stat64_t64
*statp
)
94 /* We have to set the close-on-exit flag if the user provided the
97 && __glibc_unlikely (__fcntl64_nocancel (fd
, F_SETFD
, FD_CLOEXEC
) < 0))
100 /* The st_blksize value of the directory is used as a hint for the
101 size of the buffer which receives struct dirent values from the
102 kernel. st_blksize is limited to max_buffer_size, in case the
103 file system provides a bogus value. */
104 enum { max_buffer_size
= 1048576 };
106 enum { allocation_size
= 32768 };
107 _Static_assert (allocation_size
>= sizeof (struct dirent64
),
108 "allocation_size < sizeof (struct dirent64)");
110 /* Increase allocation if requested, but not if the value appears to
111 be bogus. It will be between 32Kb and 1Mb. */
112 size_t allocation
= MIN (MAX ((size_t) statp
->st_blksize
, (size_t)
113 allocation_size
), (size_t) max_buffer_size
);
115 DIR *dirp
= (DIR *) malloc (sizeof (DIR) + allocation
);
119 __close_nocancel_nostatus (fd
);
125 __libc_lock_init (dirp
->lock
);
127 dirp
->allocation
= allocation
;