xref: /dragonfly/lib/libc/sys/chflags.2 (revision 7d2302ac)
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28.\"	@(#)chflags.2	8.3 (Berkeley) 5/2/95
29.\" $FreeBSD: src/lib/libc/sys/chflags.2,v 1.11.2.7 2001/12/14 18:34:00 ru Exp $
30.\"
31.Dd October 6, 2019
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 UF_NODUMP
117Do not dump the file.
118.It Dv UF_IMMUTABLE
119The file may not be changed.
120.It Dv UF_APPEND
121The file may only be appended to.
122.It Dv UF_OPAQUE
123The directory is opaque when viewed through a union stack.
124.It Dv UF_NOUNLINK
125The file may not be renamed or deleted.
126.It Dv UF_NOHISTORY
127Do not retain history for file.
128.It Dv UF_CACHE
129Enable
130.Xr swapcache 8
131data caching.
132The flag is recursive and need only be set on a top-level directory.
133.It Dv SF_ARCHIVED
134The file may be archived.
135.It Dv SF_IMMUTABLE
136The file may not be changed.
137.It Dv SF_APPEND
138The file may only be appended to.
139.It Dv SF_NOUNLINK
140The file may not be renamed or deleted.
141.It Dv SF_NOHISTORY
142Do not retain history for file.
143.It Dv SF_NOCACHE
144Disable
145.Xr swapcache 8
146data caching.
147The flag is recursive and need only be set on a top-level directory.
148.El
149.Pp
150The
151.Dq UF_
152prefixed
153flags may be set or unset by either the owner of a file or the super-user.
154.Pp
155The
156.Dq SF_
157prefixed
158flags may only be set or unset by the super-user.
159Attempts by the non-super-user to set the super-user only flags
160are silently ignored.
161These flags may be set at any time, but normally may only be unset when
162the system is in single-user mode.
163(See
164.Xr init 8
165for details.)
166.Sh RETURN VALUES
167.Rv -std
168.Sh ERRORS
169.Fn Chflags
170will fail if:
171.Bl -tag -width Er
172.It Bq Er ENOTDIR
173A component of the path prefix is not a directory.
174.It Bq Er ENAMETOOLONG
175A component of a pathname exceeded 255 characters,
176or an entire path name exceeded 1023 characters.
177.It Bq Er ENOENT
178The named file does not exist.
179.It Bq Er EACCES
180Search permission is denied for a component of the path prefix.
181.It Bq Er ELOOP
182Too many symbolic links were encountered in translating the pathname.
183.It Bq Er EPERM
184The effective user ID does not match the owner of the file and
185the effective user ID is not the super-user.
186.It Bq Er EROFS
187The named file resides on a read-only file system.
188.It Bq Er EFAULT
189.Fa Path
190points outside the process's allocated address space.
191.It Bq Er EIO
192An
193.Tn I/O
194error occurred while reading from or writing to the file system.
195.It Bq Er EOPNOTSUPP
196The underlying file system does not support file flags.
197.El
198.Pp
199.Fn Fchflags
200will fail if:
201.Bl -tag -width Er
202.It Bq Er EBADF
203The descriptor is not valid.
204.It Bq Er EINVAL
205.Fa fd
206refers to a socket, not to a file.
207.It Bq Er EPERM
208The effective user ID does not match the owner of the file and
209the effective user ID is not the super-user.
210.It Bq Er EROFS
211The file resides on a read-only file system.
212.It Bq Er EIO
213An
214.Tn I/O
215error occurred while reading from or writing to the file system.
216.It Bq Er EOPNOTSUPP
217The underlying file system does not support file flags.
218.El
219.Sh SEE ALSO
220.Xr chflags 1 ,
221.Xr fflagstostr 3 ,
222.Xr strtofflags 3 ,
223.Xr init 8 ,
224.Xr swapcache 8
225.Sh HISTORY
226The
227.Nm chflags
228and
229.Nm fchflags
230functions first appeared in
231.Bx 4.4 .
232