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 October 20, 2018 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.It Dv AT_BENEATH 98Only allow to change flags for a file which is beneath of 99the starting directory. 100.El 101.Pp 102If 103.Fn chflagsat 104is passed the special value 105.Dv AT_FDCWD 106in the 107.Fa fd 108parameter, the current working directory is used. 109If also 110.Fa atflag 111is zero, the behavior is identical to a call to 112.Fn chflags . 113.Pp 114The flags specified are formed by 115.Em or Ns 'ing 116the following values 117.Pp 118.Bl -tag -width ".Dv SF_IMMUTABLE" -compact -offset indent 119.It Dv SF_APPEND 120The file may only be appended to. 121.It Dv SF_ARCHIVED 122The file has been archived. 123This flag means the opposite of the DOS, Windows and CIFS 124FILE_ATTRIBUTE_ARCHIVE attribute. 125This flag has been deprecated, and may be removed in a future release. 126.It Dv SF_IMMUTABLE 127The file may not be changed. 128.It Dv SF_NOUNLINK 129The file may not be renamed or deleted. 130.It Dv SF_SNAPSHOT 131The file is a snapshot file. 132.It Dv UF_APPEND 133The file may only be appended to. 134.It Dv UF_ARCHIVE 135The file needs to be archived. 136This flag has the same meaning as the DOS, Windows and CIFS 137FILE_ATTRIBUTE_ARCHIVE attribute. 138Filesystems in FreeBSD may or may not have special handling for this flag. 139For instance, ZFS tracks changes to files and will set this bit when a 140file is updated. 141UFS only stores the flag, and relies on the application to change it when 142needed. 143.It Dv UF_HIDDEN 144The file may be hidden from directory listings at the application's 145discretion. 146The file has the DOS, Windows and CIFS FILE_ATTRIBUTE_HIDDEN attribute. 147.It Dv UF_IMMUTABLE 148The file may not be changed. 149.It Dv UF_NODUMP 150Do not dump the file. 151.It Dv UF_NOUNLINK 152The file may not be renamed or deleted. 153.It Dv UF_OFFLINE 154The file is offline, or has the Windows and CIFS FILE_ATTRIBUTE_OFFLINE 155attribute. 156Filesystems in FreeBSD store and display this flag, but do not provide any 157special handling when it is set. 158.It Dv UF_OPAQUE 159The directory is opaque when viewed through a union stack. 160.It Dv UF_READONLY 161The file is read only, and may not be written or appended. 162Filesystems may use this flag to maintain compatibility with the DOS, Windows 163and CIFS FILE_ATTRIBUTE_READONLY attribute. 164.It Dv UF_REPARSE 165The file contains a Windows reparse point and has the Windows and CIFS 166FILE_ATTRIBUTE_REPARSE_POINT attribute. 167.It Dv UF_SPARSE 168The file has the Windows FILE_ATTRIBUTE_SPARSE_FILE attribute. 169This may also be used by a filesystem to indicate a sparse file. 170.It Dv UF_SYSTEM 171The file has the DOS, Windows and CIFS FILE_ATTRIBUTE_SYSTEM attribute. 172Filesystems in FreeBSD may store and display this flag, but do not provide 173any special handling when it is set. 174.El 175.Pp 176If one of 177.Dv SF_IMMUTABLE , SF_APPEND , 178or 179.Dv SF_NOUNLINK 180is set a non-super-user cannot change any flags and even the super-user 181can change flags only if securelevel is 0. 182(See 183.Xr init 8 184for details.) 185.Pp 186The 187.Dv UF_IMMUTABLE , UF_APPEND , UF_NOUNLINK , UF_NODUMP , 188and 189.Dv UF_OPAQUE 190flags may be set or unset by either the owner of a file or the super-user. 191.Pp 192The 193.Dv SF_IMMUTABLE , SF_APPEND , SF_NOUNLINK , 194and 195.Dv SF_ARCHIVED 196flags may only be set or unset by the super-user. 197Attempts to toggle these flags by non-super-users are rejected. 198These flags may be set at any time, but normally may only be unset when 199the system is in single-user mode. 200(See 201.Xr init 8 202for details.) 203.Pp 204The implementation of all flags is filesystem-dependent. 205See the description of the 206.Dv UF_ARCHIVE 207flag above for one example of the differences in behavior. 208Care should be exercised when writing applications to account for 209support or lack of support of these flags in various filesystems. 210.Pp 211The 212.Dv SF_SNAPSHOT 213flag is maintained by the system and cannot be toggled. 214.Sh RETURN VALUES 215.Rv -std 216.Sh ERRORS 217The 218.Fn chflags 219system call will fail if: 220.Bl -tag -width Er 221.It Bq Er ENOTDIR 222A component of the path prefix is not a directory. 223.It Bq Er ENAMETOOLONG 224A component of a pathname exceeded 255 characters, 225or an entire path name exceeded 1023 characters. 226.It Bq Er ENOENT 227The named file does not exist. 228.It Bq Er EACCES 229Search permission is denied for a component of the path prefix. 230.It Bq Er ELOOP 231Too many symbolic links were encountered in translating the pathname. 232.It Bq Er EPERM 233The effective user ID does not match the owner of the file and 234the effective user ID is not the super-user. 235.It Bq Er EPERM 236One of 237.Dv SF_IMMUTABLE , SF_APPEND , 238or 239.Dv SF_NOUNLINK 240is set and the user is either not the super-user or 241securelevel is greater than 0. 242.It Bq Er EPERM 243A non-super-user attempted to toggle one of 244.Dv SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND , 245or 246.Dv SF_NOUNLINK . 247.It Bq Er EPERM 248An attempt was made to toggle the 249.Dv SF_SNAPSHOT 250flag. 251.It Bq Er EROFS 252The named file resides on a read-only file system. 253.It Bq Er EFAULT 254The 255.Fa path 256argument 257points outside the process's allocated address space. 258.It Bq Er EIO 259An 260.Tn I/O 261error occurred while reading from or writing to the file system. 262.It Bq Er EOPNOTSUPP 263The underlying file system does not support file flags, or 264does not support all of the flags set in 265.Fa flags . 266.El 267.Pp 268The 269.Fn fchflags 270system call will fail if: 271.Bl -tag -width Er 272.It Bq Er EBADF 273The descriptor is not valid. 274.It Bq Er EINVAL 275The 276.Fa fd 277argument 278refers to a socket, not to a file. 279.It Bq Er EPERM 280The effective user ID does not match the owner of the file and 281the effective user ID is not the super-user. 282.It Bq Er EPERM 283One of 284.Dv SF_IMMUTABLE , SF_APPEND , 285or 286.Dv SF_NOUNLINK 287is set and the user is either not the super-user or 288securelevel is greater than 0. 289.It Bq Er EPERM 290A non-super-user attempted to toggle one of 291.Dv SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND , 292or 293.Dv SF_NOUNLINK . 294.It Bq Er EPERM 295An attempt was made to toggle the 296.Dv SF_SNAPSHOT 297flag. 298.It Bq Er EROFS 299The file resides on a read-only file system. 300.It Bq Er EIO 301An 302.Tn I/O 303error occurred while reading from or writing to the file system. 304.It Bq Er EOPNOTSUPP 305The underlying file system does not support file flags, or 306does not support all of the flags set in 307.Fa flags . 308.It Bq Er ENOTCAPABLE 309The 310.Dv AT_BENEATH 311flag was specified but 312.Fa path 313is not strictly relative to the starting directory. 314For example, 315.Fa path 316is absolute or includes a ".." component that escapes the starting directory. 317.El 318.Sh SEE ALSO 319.Xr chflags 1 , 320.Xr fflagstostr 3 , 321.Xr strtofflags 3 , 322.Xr init 8 , 323.Xr mount_unionfs 8 324.Sh HISTORY 325The 326.Fn chflags 327and 328.Fn fchflags 329system calls first appeared in 330.Bx 4.4 . 331The 332.Fn lchflags 333system call first appeared in 334.Fx 5.0 . 335The 336.Fn chflagsat 337system call first appeared in 338.Fx 10.0 . 339