1.\" Copyright (c) 1989, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. 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.Nm chflagsat 39.Nd set file flags 40.Sh LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In sys/stat.h 44.In unistd.h 45.Ft int 46.Fn chflags "const char *path" "unsigned long flags" 47.Ft int 48.Fn lchflags "const char *path" "unsigned long flags" 49.Ft int 50.Fn fchflags "int fd" "unsigned long flags" 51.Ft int 52.Fn chflagsat "int fd" "const char *path" "unsigned long flags" "int atflag" 53.Sh DESCRIPTION 54The file whose name 55is given by 56.Fa path 57or referenced by the descriptor 58.Fa fd 59has its flags changed to 60.Fa flags . 61.Pp 62The 63.Fn lchflags 64system call is like 65.Fn chflags 66except in the case where the named file is a symbolic link, 67in which case 68.Fn lchflags 69will change the flags of the link itself, 70rather than the file it points to. 71.Pp 72The 73.Fn chflagsat 74is equivalent to either 75.Fn chflags 76or 77.Fn lchflags 78depending on the 79.Fa atflag 80except in the case where 81.Fa path 82specifies a relative path. 83In this case the file to be changed is determined relative to the directory 84associated with the file descriptor 85.Fa fd 86instead of the current working directory. 87The values for the 88.Fa atflag 89are constructed by a bitwise-inclusive OR of flags from the following list, 90defined in 91.In fcntl.h : 92.Bl -tag -width indent 93.It Dv AT_SYMLINK_NOFOLLOW 94If 95.Fa path 96names a symbolic link, then the flags of the symbolic link are changed. 97.El 98.Pp 99If 100.Fn chflagsat 101is passed the special value 102.Dv AT_FDCWD 103in the 104.Fa fd 105parameter, the current working directory is used. 106If also 107.Fa atflag 108is zero, the behavior is identical to a call to 109.Fn chflags . 110.Pp 111The flags specified are formed by 112.Em or Ns 'ing 113the following values 114.Pp 115.Bl -tag -width ".Dv SF_IMMUTABLE" -compact -offset indent 116.It Dv SF_APPEND 117The file may only be appended to. 118.It Dv SF_ARCHIVED 119The file has been archived. 120This flag means the opposite of the DOS, Windows and CIFS 121FILE_ATTRIBUTE_ARCHIVE attribute. 122This flag has been deprecated, and may be removed in a future release. 123.It Dv SF_IMMUTABLE 124The file may not be changed. 125.It Dv SF_NOUNLINK 126The file may not be renamed or deleted. 127.It Dv SF_SNAPSHOT 128The file is a snapshot file. 129.It Dv UF_APPEND 130The file may only be appended to. 131.It Dv UF_ARCHIVE 132The file needs to be archived. 133This flag has the same meaning as the DOS, Windows and CIFS 134FILE_ATTRIBUTE_ARCHIVE attribute. 135Filesystems in FreeBSD may or may not have special handling for this flag. 136For instance, ZFS tracks changes to files and will set this bit when a 137file is updated. 138UFS only stores the flag, and relies on the application to change it when 139needed. 140.It Dv UF_HIDDEN 141The file may be hidden from directory listings at the application's 142discretion. 143The file has the DOS, Windows and CIFS FILE_ATTRIBUTE_HIDDEN attribute. 144.It Dv UF_IMMUTABLE 145The file may not be changed. 146.It Dv UF_NODUMP 147Do not dump the file. 148.It Dv UF_NOUNLINK 149The file may not be renamed or deleted. 150.It Dv UF_OFFLINE 151The file is offline, or has the Windows and CIFS FILE_ATTRIBUTE_OFFLINE 152attribute. 153Filesystems in FreeBSD store and display this flag, but do not provide any 154special handling when it is set. 155.It Dv UF_OPAQUE 156The directory is opaque when viewed through a union stack. 157.It Dv UF_READONLY 158The file is read only, and may not be written or appended. 159Filesystems may use this flag to maintain compatibility with the DOS, Windows 160and CIFS FILE_ATTRIBUTE_READONLY attribute. 161.It Dv UF_REPARSE 162The file contains a Windows reparse point and has the Windows and CIFS 163FILE_ATTRIBUTE_REPARSE_POINT attribute. 164.It Dv UF_SPARSE 165The file has the Windows FILE_ATTRIBUTE_SPARSE_FILE attribute. 166This may also be used by a filesystem to indicate a sparse file. 167.It Dv UF_SYSTEM 168The file has the DOS, Windows and CIFS FILE_ATTRIBUTE_SYSTEM attribute. 169Filesystems in FreeBSD may store and display this flag, but do not provide 170any special handling when it is set. 171.El 172.Pp 173If one of 174.Dv SF_IMMUTABLE , SF_APPEND , 175or 176.Dv SF_NOUNLINK 177is set a non-super-user cannot change any flags and even the super-user 178can change flags only if securelevel is 0. 179(See 180.Xr init 8 181for details.) 182.Pp 183The 184.Dv UF_IMMUTABLE , UF_APPEND , UF_NOUNLINK , UF_NODUMP , 185and 186.Dv UF_OPAQUE 187flags may be set or unset by either the owner of a file or the super-user. 188.Pp 189The 190.Dv SF_IMMUTABLE , SF_APPEND , SF_NOUNLINK , 191and 192.Dv SF_ARCHIVED 193flags may only be set or unset by the super-user. 194Attempts to toggle these flags by non-super-users are rejected. 195These flags may be set at any time, but normally may only be unset when 196the system is in single-user mode. 197(See 198.Xr init 8 199for details.) 200.Pp 201The implementation of all flags is filesystem-dependent. 202See the description of the 203.Dv UF_ARCHIVE 204flag above for one example of the differences in behavior. 205Care should be exercised when writing applications to account for 206support or lack of support of these flags in various filesystems. 207.Pp 208The 209.Dv SF_SNAPSHOT 210flag is maintained by the system and cannot be toggled. 211.Sh RETURN VALUES 212.Rv -std 213.Sh ERRORS 214The 215.Fn chflags 216system call will fail if: 217.Bl -tag -width Er 218.It Bq Er ENOTDIR 219A component of the path prefix is not a directory. 220.It Bq Er ENAMETOOLONG 221A component of a pathname exceeded 255 characters, 222or an entire path name exceeded 1023 characters. 223.It Bq Er ENOENT 224The named file does not exist. 225.It Bq Er EACCES 226Search permission is denied for a component of the path prefix. 227.It Bq Er ELOOP 228Too many symbolic links were encountered in translating the pathname. 229.It Bq Er EPERM 230The effective user ID does not match the owner of the file and 231the effective user ID is not the super-user. 232.It Bq Er EPERM 233One of 234.Dv SF_IMMUTABLE , SF_APPEND , 235or 236.Dv SF_NOUNLINK 237is set and the user is either not the super-user or 238securelevel is greater than 0. 239.It Bq Er EPERM 240A non-super-user attempted to toggle one of 241.Dv SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND , 242or 243.Dv SF_NOUNLINK . 244.It Bq Er EPERM 245An attempt was made to toggle the 246.Dv SF_SNAPSHOT 247flag. 248.It Bq Er EROFS 249The named file resides on a read-only file system. 250.It Bq Er EFAULT 251The 252.Fa path 253argument 254points outside the process's allocated address space. 255.It Bq Er EIO 256An 257.Tn I/O 258error occurred while reading from or writing to the file system. 259.It Bq Er EOPNOTSUPP 260The underlying file system does not support file flags, or 261does not support all of the flags set in 262.Fa flags . 263.El 264.Pp 265The 266.Fn fchflags 267system call will fail if: 268.Bl -tag -width Er 269.It Bq Er EBADF 270The descriptor is not valid. 271.It Bq Er EINVAL 272The 273.Fa fd 274argument 275refers to a socket, not to a file. 276.It Bq Er EPERM 277The effective user ID does not match the owner of the file and 278the effective user ID is not the super-user. 279.It Bq Er EPERM 280One of 281.Dv SF_IMMUTABLE , SF_APPEND , 282or 283.Dv SF_NOUNLINK 284is set and the user is either not the super-user or 285securelevel is greater than 0. 286.It Bq Er EPERM 287A non-super-user attempted to toggle one of 288.Dv SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND , 289or 290.Dv SF_NOUNLINK . 291.It Bq Er EPERM 292An attempt was made to toggle the 293.Dv SF_SNAPSHOT 294flag. 295.It Bq Er EROFS 296The file resides on a read-only file system. 297.It Bq Er EIO 298An 299.Tn I/O 300error occurred while reading from or writing to the file system. 301.It Bq Er EOPNOTSUPP 302The underlying file system does not support file flags, or 303does not support all of the flags set in 304.Fa flags . 305.El 306.Sh SEE ALSO 307.Xr chflags 1 , 308.Xr fflagstostr 3 , 309.Xr strtofflags 3 , 310.Xr init 8 , 311.Xr mount_unionfs 8 312.Sh HISTORY 313The 314.Fn chflags 315and 316.Fn fchflags 317system calls first appeared in 318.Bx 4.4 . 319The 320.Fn lchflags 321system call first appeared in 322.Fx 5.0 . 323The 324.Fn chflagsat 325system call first appeared in 326.Fx 10.0 . 327