xref: /dragonfly/lib/libc/sys/chflags.2 (revision 73610d44) 
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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.\" $DragonFly: src/lib/libc/sys/chflags.2,v 1.5 2008/11/11 00:55:49 pavalos Exp $
31.\"
32.Dd February 13, 2015
33.Dt CHFLAGS 2
34.Os
35.Sh NAME
36.Nm chflags ,
37.Nm lchflags ,
38.Nm fchflags ,
39.Nm chflagsat
40.Nd set file flags
41.Sh LIBRARY
42.Lb libc
43.Sh SYNOPSIS
44.In sys/stat.h
45.In unistd.h
46.Ft int
47.Fn chflags "const char *path"  "u_long flags"
48.Ft int
49.Fn lchflags "const char *path" "u_long flags"
50.Ft int
51.Fn fchflags "int fd" "u_long flags"
52.Ft int
53.Fn chflagsat "int fd" "const char *path" "u_long flags" "int atflag"
54.Sh DESCRIPTION
55The file whose name
56is given by
57.Fa path
58or referenced by the descriptor
59.Fa fd
60has its flags changed to
61.Fa flags .
62.Pp
63The
64.Fn lchflags
65system call is like
66.Fn chflags
67except in the case where the named file is a symbolic link,
68in which case
69.Fn lchflags
70will change the flags of the link itself,
71rather than the file it points to.
72.Pp
73The
74.Fn chflagsat
75is equivalent to either
76.Fn chflags
77or
78.Fn lchflags
79depending on the
80.Fa atflag
81except in the case where
82.Fa path
83specifies a relative path.
84In this case the file to be changed is determined relative to the directory
85associated with the file descriptor
86.Fa fd
87instead of the current working directory.
88The values for the
89.Fa atflag
90are constructed by a bitwise-inclusive OR of flags from the following list,
91defined in
92.In fcntl.h :
93.Bl -tag -width indent
94.It Dv AT_SYMLINK_NOFOLLOW
95If
96.Fa path
97names a symbolic link, then the flags of the symbolic link are changed.
98.El
99.Pp
100If
101.Fn chflagsat
102is passed the special value
103.Dv AT_FDCWD
104in the
105.Fa fd
106parameter, the current working directory is used.
107If also
108.Fa atflag
109is zero, the behavior is identical to a call to
110.Fn chflags .
111.Pp
112The flags specified are formed by
113.Em or Ns 'ing
114the following values
115.Pp
116.Bl -tag -width "SF_IMMUTABLE" -compact -offset indent
117.It UF_NODUMP
118Do not dump the file.
119.It UF_IMMUTABLE
120The file may not be changed.
121.It UF_APPEND
122The file may only be appended to.
123.It UF_OPAQUE
124The directory is opaque when viewed through a union stack.
125.It UF_NOUNLINK
126The file may not be renamed or deleted.
127.It UF_NOHISTORY
128Do not retain history for file.
129.It UF_CACHE
130Enable
131.Xr swapcache 8
132data caching.
133The flag is recursive and need only be set on a top-level directory.
134.It SF_ARCHIVED
135The file may be archived.
136.It SF_IMMUTABLE
137The file may not be changed.
138.It SF_APPEND
139The file may only be appended to.
140.It SF_NOUNLINK
141The file may not be renamed or deleted.
142.It SF_NOHISTORY
143Do not retain history for file.
144.It SF_NOCACHE
145Disable
146.Xr swapcache 8
147data caching.
148The flag is recursive and need only be set on a top-level directory.
149.El
150.Pp
151The
152.Dq UF_
153prefixed
154flags may be set or unset by either the owner of a file or the super-user.
155.Pp
156The
157.Dq SF_
158prefixed
159flags may only be set or unset by the super-user.
160Attempts by the non-super-user to set the super-user only flags
161are silently ignored.
162These flags may be set at any time, but normally may only be unset when
163the system is in single-user mode.
164(See
165.Xr init 8
166for details.)
167.Sh RETURN VALUES
168.Rv -std
169.Sh ERRORS
170.Fn Chflags
171will fail if:
172.Bl -tag -width Er
173.It Bq Er ENOTDIR
174A component of the path prefix is not a directory.
175.It Bq Er ENAMETOOLONG
176A component of a pathname exceeded 255 characters,
177or an entire path name exceeded 1023 characters.
178.It Bq Er ENOENT
179The named file does not exist.
180.It Bq Er EACCES
181Search permission is denied for a component of the path prefix.
182.It Bq Er ELOOP
183Too many symbolic links were encountered in translating the pathname.
184.It Bq Er EPERM
185The effective user ID does not match the owner of the file and
186the effective user ID is not the super-user.
187.It Bq Er EROFS
188The named file resides on a read-only file system.
189.It Bq Er EFAULT
190.Fa Path
191points outside the process's allocated address space.
192.It Bq Er EIO
193An
194.Tn I/O
195error occurred while reading from or writing to the file system.
196.It Bq Er EOPNOTSUPP
197The underlying file system does not support file flags.
198.El
199.Pp
200.Fn Fchflags
201will fail if:
202.Bl -tag -width Er
203.It Bq Er EBADF
204The descriptor is not valid.
205.It Bq Er EINVAL
206.Fa fd
207refers to a socket, not to a file.
208.It Bq Er EPERM
209The effective user ID does not match the owner of the file and
210the effective user ID is not the super-user.
211.It Bq Er EROFS
212The file resides on a read-only file system.
213.It Bq Er EIO
214An
215.Tn I/O
216error occurred while reading from or writing to the file system.
217.It Bq Er EOPNOTSUPP
218The underlying file system does not support file flags.
219.El
220.Sh SEE ALSO
221.Xr chflags 1 ,
222.Xr fflagstostr 3 ,
223.Xr strtofflags 3 ,
224.Xr init 8 ,
225.Xr mount_union 8 ,
226.Xr swapcache 8
227.Sh HISTORY
228The
229.Nm chflags
230and
231.Nm fchflags
232functions first appeared in
233.Bx 4.4 .
234