1 /* Get file-specific information about a file. Linux version.
2 Copyright (C) 1991-2014 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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 <http://www.gnu.org/licenses/>. */
21 #include <stdio_ext.h>
24 #include <sys/sysmacros.h>
27 #include "linux_fsinfo.h"
28 #include <not-cancel.h>
30 static long int posix_pathconf (const char *file
, int name
);
32 /* Define this first, so it can be inlined. */
33 #define __pathconf static posix_pathconf
34 #include <sysdeps/posix/pathconf.c>
37 /* Get file-specific information about FILE. */
39 __pathconf (const char *file
, int name
)
46 return __statfs_link_max (__statfs (file
, &fsbuf
), &fsbuf
, file
, -1);
48 case _PC_FILESIZEBITS
:
49 return __statfs_filesize_max (__statfs (file
, &fsbuf
), &fsbuf
);
52 return __statfs_symlinks (__statfs (file
, &fsbuf
), &fsbuf
);
54 case _PC_CHOWN_RESTRICTED
:
55 return __statfs_chown_restricted (__statfs (file
, &fsbuf
), &fsbuf
);
58 return posix_pathconf (file
, name
);
64 distinguish_extX (const struct statfs
*fsbuf
, const char *file
, int fd
)
70 if ((file
== NULL
? fstat64 (fd
, &st
) : stat64 (file
, &st
)) != 0)
71 /* Strange. The statfd call worked, but stat fails. Default to
72 the more pessimistic value. */
75 __snprintf (buf
, sizeof (buf
), "/sys/dev/block/%u:%u",
76 gnu_dev_major (st
.st_dev
), gnu_dev_minor (st
.st_dev
));
78 ssize_t n
= __readlink (buf
, path
, sizeof (path
));
79 if (n
!= -1 && n
< sizeof (path
))
82 char *base
= strdupa (basename (path
));
83 __snprintf (path
, sizeof (path
), "/sys/fs/ext4/%s", base
);
85 return __access (path
, F_OK
) == 0 ? EXT4_LINK_MAX
: EXT2_LINK_MAX
;
88 /* XXX Is there a better way to distinguish ext2/3 from ext4 than
89 iterating over the mounted filesystems and compare the device
91 FILE *mtab
= __setmntent ("/proc/mounts", "r");
93 mtab
= __setmntent (_PATH_MOUNTED
, "r");
95 /* By default be conservative. */
96 long int result
= EXT2_LINK_MAX
;
102 /* No locking needed. */
103 (void) __fsetlocking (mtab
, FSETLOCKING_BYCALLER
);
105 while (__getmntent_r (mtab
, &mntbuf
, tmpbuf
, sizeof (tmpbuf
)))
107 if (strcmp (mntbuf
.mnt_type
, "ext2") != 0
108 && strcmp (mntbuf
.mnt_type
, "ext3") != 0
109 && strcmp (mntbuf
.mnt_type
, "ext4") != 0)
113 if (stat64 (mntbuf
.mnt_dir
, &fsst
) >= 0
114 && st
.st_dev
== fsst
.st_dev
)
116 if (strcmp (mntbuf
.mnt_type
, "ext4") == 0)
117 result
= EXT4_LINK_MAX
;
122 /* Close the file. */
130 /* Used like: return statfs_link_max (__statfs (name, &buf), &buf); */
132 __statfs_link_max (int result
, const struct statfs
*fsbuf
, const char *file
,
138 /* Not possible, return the default value. */
139 return LINUX_LINK_MAX
;
141 /* Some error occured. */
145 switch (fsbuf
->f_type
)
147 case EXT2_SUPER_MAGIC
:
148 /* Unfortunately the kernel does not return a different magic number
149 for ext4. This would be necessary to easily detect etx4 since it
150 has a different LINK_MAX value. Therefore we have to find it out
152 return distinguish_extX (fsbuf
, file
, fd
);
154 case F2FS_SUPER_MAGIC
:
155 return F2FS_LINK_MAX
;
157 case MINIX_SUPER_MAGIC
:
158 case MINIX_SUPER_MAGIC2
:
159 return MINIX_LINK_MAX
;
161 case MINIX2_SUPER_MAGIC
:
162 case MINIX2_SUPER_MAGIC2
:
163 return MINIX2_LINK_MAX
;
165 case XENIX_SUPER_MAGIC
:
166 return XENIX_LINK_MAX
;
168 case SYSV4_SUPER_MAGIC
:
169 case SYSV2_SUPER_MAGIC
:
170 return SYSV_LINK_MAX
;
172 case COH_SUPER_MAGIC
:
179 case REISERFS_SUPER_MAGIC
:
180 return REISERFS_LINK_MAX
;
182 case XFS_SUPER_MAGIC
:
185 case LUSTRE_SUPER_MAGIC
:
186 return LUSTRE_LINK_MAX
;
189 return LINUX_LINK_MAX
;
194 /* Used like: return statfs_filesize_max (__statfs (name, &buf), &buf); */
196 __statfs_filesize_max (int result
, const struct statfs
*fsbuf
)
201 /* Not possible, return the default value. */
204 /* Some error occured. */
208 switch (fsbuf
->f_type
)
210 case F2FS_SUPER_MAGIC
:
213 case BTRFS_SUPER_MAGIC
:
216 case EXT2_SUPER_MAGIC
:
219 case REISERFS_SUPER_MAGIC
:
220 case XFS_SUPER_MAGIC
:
221 case SMB_SUPER_MAGIC
:
222 case NTFS_SUPER_MAGIC
:
223 case UDF_SUPER_MAGIC
:
224 case JFS_SUPER_MAGIC
:
225 case VXFS_SUPER_MAGIC
:
226 case CGROUP_SUPER_MAGIC
:
227 case LUSTRE_SUPER_MAGIC
:
230 case MSDOS_SUPER_MAGIC
:
231 case JFFS_SUPER_MAGIC
:
232 case JFFS2_SUPER_MAGIC
:
233 case NCP_SUPER_MAGIC
:
234 case ROMFS_SUPER_MAGIC
:
243 /* Used like: return statfs_link_max (__statfs (name, &buf), &buf); */
245 __statfs_symlinks (int result
, const struct statfs
*fsbuf
)
250 /* Not possible, return the default value. */
253 /* Some error occured. */
257 switch (fsbuf
->f_type
)
259 case ADFS_SUPER_MAGIC
:
262 case DEVPTS_SUPER_MAGIC
:
263 case EFS_SUPER_MAGIC
:
265 case MSDOS_SUPER_MAGIC
:
266 case NTFS_SUPER_MAGIC
:
267 case QNX4_SUPER_MAGIC
:
268 case ROMFS_SUPER_MAGIC
:
269 /* No symlink support. */
278 /* Used like: return __statfs_chown_restricted (__statfs (name, &buf), &buf);*/
280 __statfs_chown_restricted (int result
, const struct statfs
*fsbuf
)
285 /* Not possible, return the default value. */
288 /* Some error occured. */
292 #if __ASSUME_XFS_RESTRICTED_CHOWN
298 switch (fsbuf
->f_type
)
300 case XFS_SUPER_MAGIC
:
302 /* Read the value from /proc/sys/fs/xfs/restrict_chown. If we cannot
303 read it default to assume the restriction is in place. */
304 fd
= open_not_cancel_2 ("/proc/sys/fs/xfs/restrict_chown", O_RDONLY
);
308 if (TEMP_FAILURE_RETRY (read_not_cancel (fd
, buf
, 2)) == 2
309 && buf
[0] >= '0' && buf
[0] <= '1')
310 retval
= buf
[0] - '0';
312 close_not_cancel_no_status (fd
);
314 __set_errno (save_errno
);