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Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)chflags.2 8.3 (Berkeley) 5/2/95 29.\" $FreeBSD$ 30.\" 31.Dd March 22, 2013 32.Dt CHFLAGS 2 33.Os 34.Sh NAME 35.Nm chflags , 36.Nm lchflags , 37.Nm fchflags 38.Nd set file flags 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In sys/stat.h 43.In unistd.h 44.Ft int 45.Fn chflags "const char *path" "unsigned long flags" 46.Ft int 47.Fn lchflags "const char *path" "unsigned long flags" 48.Ft int 49.Fn fchflags "int fd" "unsigned long flags" 50.Ft int 51.Fn chflagsat "int fd" "const char *path" "unsigned long flags" "int atflag" 52.Sh DESCRIPTION 53The file whose name 54is given by 55.Fa path 56or referenced by the descriptor 57.Fa fd 58has its flags changed to 59.Fa flags . 60.Pp 61The 62.Fn lchflags 63system call is like 64.Fn chflags 65except in the case where the named file is a symbolic link, 66in which case 67.Fn lchflags 68will change the flags of the link itself, 69rather than the file it points to. 70.Pp 71The 72.Fn chflagsat 73is equivalent to either 74.Fn chflags 75or 76.Fn lchflags 77depending on the 78.Fa atflag 79except in the case where 80.Fa path 81specifies a relative path. 82In this case the file to be changed is determined relative to the directory 83associated with the file descriptor 84.Fa fd 85instead of the current working directory. 86The values for the 87.Fa atflag 88are constructed by a bitwise-inclusive OR of flags from the following list, 89defined in 90.In fcntl.h : 91.Bl -tag -width indent 92.It Dv AT_SYMLINK_NOFOLLOW 93If 94.Fa path 95names a symbolic link, then the flags of the symbolic link are changed. 96.El 97.Pp 98If 99.Fn chflagsat 100is passed the special value 101.Dv AT_FDCWD 102in the 103.Fa fd 104parameter, the current working directory is used. 105If also 106.Fa atflag 107is zero, the behavior is identical to a call to 108.Fn chflags . 109.Pp 110The flags specified are formed by 111.Em or Ns 'ing 112the following values 113.Pp 114.Bl -tag -width ".Dv SF_IMMUTABLE" -compact -offset indent 115.It Dv SF_APPEND 116The file may only be appended to. 117.It Dv SF_ARCHIVED 118The file has been archived. 119This flag means the opposite of the DOS, Windows and CIFS 120FILE_ATTRIBUTE_ARCHIVE attribute. 121This flag has been deprecated, and may be removed in a future release. 122.It Dv SF_IMMUTABLE 123The file may not be changed. 124.It Dv SF_NOUNLINK 125The file may not be renamed or deleted. 126.It Dv SF_SNAPSHOT 127The file is a snapshot file. 128.It Dv UF_APPEND 129The file may only be appended to. 130.It Dv UF_ARCHIVE 131The file needs to be archived. 132This flag has the same meaning as the DOS, Windows and CIFS 133FILE_ATTRIBUTE_ARCHIVE attribute. 134Filesystems in FreeBSD may or may not have special handling for this flag. 135For instance, ZFS tracks changes to files and will set this bit when a 136file is updated. 137UFS only stores the flag, and relies on the application to change it when 138needed. 139.It Dv UF_HIDDEN 140The file may be hidden from directory listings at the application's 141discretion. 142The file has the DOS, Windows and CIFS FILE_ATTRIBUTE_HIDDEN attribute. 143.It Dv UF_IMMUTABLE 144The file may not be changed. 145.It Dv UF_NODUMP 146Do not dump the file. 147.It Dv UF_NOUNLINK 148The file may not be renamed or deleted. 149.It Dv UF_OFFLINE 150The file is offline, or has the Windows and CIFS FILE_ATTRIBUTE_OFFLINE 151attribute. 152Filesystems in FreeBSD store and display this flag, but do not provide any 153special handling when it is set. 154.It Dv UF_OPAQUE 155The directory is opaque when viewed through a union stack. 156.It Dv UF_READONLY 157The file is read only, and may not be written or appended. 158Filesystems may use this flag to maintain compatibility with the DOS, Windows 159and CIFS FILE_ATTRIBUTE_READONLY attribute. 160.It Dv UF_REPARSE 161The file contains a Windows reparse point and has the Windows and CIFS 162FILE_ATTRIBUTE_REPARSE_POINT attribute. 163.It Dv UF_SPARSE 164The file has the Windows FILE_ATTRIBUTE_SPARSE_FILE attribute. 165This may also be used by a filesystem to indicate a sparse file. 166.It Dv UF_SYSTEM 167The file has the DOS, Windows and CIFS FILE_ATTRIBUTE_SYSTEM attribute. 168Filesystems in FreeBSD may store and display this flag, but do not provide 169any special handling when it is set. 170.El 171.Pp 172If one of 173.Dv SF_IMMUTABLE , SF_APPEND , 174or 175.Dv SF_NOUNLINK 176is set a non-super-user cannot change any flags and even the super-user 177can change flags only if securelevel is 0. 178(See 179.Xr init 8 180for details.) 181.Pp 182The 183.Dv UF_IMMUTABLE , UF_APPEND , UF_NOUNLINK , UF_NODUMP , 184and 185.Dv UF_OPAQUE 186flags may be set or unset by either the owner of a file or the super-user. 187.Pp 188The 189.Dv SF_IMMUTABLE , SF_APPEND , SF_NOUNLINK , 190and 191.Dv SF_ARCHIVED 192flags may only be set or unset by the super-user. 193Attempts to toggle these flags by non-super-users are rejected. 194These flags may be set at any time, but normally may only be unset when 195the system is in single-user mode. 196(See 197.Xr init 8 198for details.) 199.Pp 200The implementation of all flags is filesystem-dependent. 201See the description of the 202.Dv UF_ARCHIVE 203flag above for one example of the differences in behavior. 204Care should be exercised when writing applications to account for 205support or lack of support of these flags in various filesystems. 206.Pp 207The 208.Dv SF_SNAPSHOT 209flag is maintained by the system and cannot be toggled. 210.Sh RETURN VALUES 211.Rv -std 212.Sh ERRORS 213The 214.Fn chflags 215system call will fail if: 216.Bl -tag -width Er 217.It Bq Er ENOTDIR 218A component of the path prefix is not a directory. 219.It Bq Er ENAMETOOLONG 220A component of a pathname exceeded 255 characters, 221or an entire path name exceeded 1023 characters. 222.It Bq Er ENOENT 223The named file does not exist. 224.It Bq Er EACCES 225Search permission is denied for a component of the path prefix. 226.It Bq Er ELOOP 227Too many symbolic links were encountered in translating the pathname. 228.It Bq Er EPERM 229The effective user ID does not match the owner of the file and 230the effective user ID is not the super-user. 231.It Bq Er EPERM 232One of 233.Dv SF_IMMUTABLE , SF_APPEND , 234or 235.Dv SF_NOUNLINK 236is set and the user is either not the super-user or 237securelevel is greater than 0. 238.It Bq Er EPERM 239A non-super-user attempted to toggle one of 240.Dv SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND , 241or 242.Dv SF_NOUNLINK . 243.It Bq Er EPERM 244An attempt was made to toggle the 245.Dv SF_SNAPSHOT 246flag. 247.It Bq Er EROFS 248The named file resides on a read-only file system. 249.It Bq Er EFAULT 250The 251.Fa path 252argument 253points outside the process's allocated address space. 254.It Bq Er EIO 255An 256.Tn I/O 257error occurred while reading from or writing to the file system. 258.It Bq Er EOPNOTSUPP 259The underlying file system does not support file flags, or 260does not support all of the flags set in 261.Fa flags . 262.El 263.Pp 264The 265.Fn fchflags 266system call will fail if: 267.Bl -tag -width Er 268.It Bq Er EBADF 269The descriptor is not valid. 270.It Bq Er EINVAL 271The 272.Fa fd 273argument 274refers to a socket, not to a file. 275.It Bq Er EPERM 276The effective user ID does not match the owner of the file and 277the effective user ID is not the super-user. 278.It Bq Er EPERM 279One of 280.Dv SF_IMMUTABLE , SF_APPEND , 281or 282.Dv SF_NOUNLINK 283is set and the user is either not the super-user or 284securelevel is greater than 0. 285.It Bq Er EPERM 286A non-super-user attempted to toggle one of 287.Dv SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND , 288or 289.Dv SF_NOUNLINK . 290.It Bq Er EPERM 291An attempt was made to toggle the 292.Dv SF_SNAPSHOT 293flag. 294.It Bq Er EROFS 295The file resides on a read-only file system. 296.It Bq Er EIO 297An 298.Tn I/O 299error occurred while reading from or writing to the file system. 300.It Bq Er EOPNOTSUPP 301The underlying file system does not support file flags, or 302does not support all of the flags set in 303.Fa flags . 304.El 305.Sh SEE ALSO 306.Xr chflags 1 , 307.Xr fflagstostr 3 , 308.Xr strtofflags 3 , 309.Xr init 8 , 310.Xr mount_unionfs 8 311.Sh HISTORY 312The 313.Fn chflags 314and 315.Fn fchflags 316system calls first appeared in 317.Bx 4.4 . 318The 319.Fn lchflags 320system call first appeared in 321.Fx 5.0 . 322The 323.Fn chflagsat 324system call first appeared in 325.Fx 10.0 . 326