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Diffstat (limited to 'lib/libsys/chflags.2')
| -rw-r--r-- | lib/libsys/chflags.2 | 356 |
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diff --git a/lib/libsys/chflags.2 b/lib/libsys/chflags.2 new file mode 100644 index 000000000000..ec190df7fb19 --- /dev/null +++ b/lib/libsys/chflags.2 @@ -0,0 +1,356 @@ +.\" Copyright (c) 1989, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.Dd March 30, 2021 +.Dt CHFLAGS 2 +.Os +.Sh NAME +.Nm chflags , +.Nm lchflags , +.Nm fchflags , +.Nm chflagsat +.Nd set file flags +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/stat.h +.In unistd.h +.Ft int +.Fn chflags "const char *path" "unsigned long flags" +.Ft int +.Fn lchflags "const char *path" "unsigned long flags" +.Ft int +.Fn fchflags "int fd" "unsigned long flags" +.Ft int +.Fn chflagsat "int fd" "const char *path" "unsigned long flags" "int atflag" +.Sh DESCRIPTION +The file whose name +is given by +.Fa path +or referenced by the descriptor +.Fa fd +has its flags changed to +.Fa flags . +.Pp +The +.Fn lchflags +system call is like +.Fn chflags +except in the case where the named file is a symbolic link, +in which case +.Fn lchflags +will change the flags of the link itself, +rather than the file it points to. +.Pp +The +.Fn chflagsat +is equivalent to either +.Fn chflags +or +.Fn lchflags +depending on the +.Fa atflag +except in the case where +.Fa path +specifies a relative path. +In this case the file to be changed is determined relative to the directory +associated with the file descriptor +.Fa fd +instead of the current working directory. +The values for the +.Fa atflag +are constructed by a bitwise-inclusive OR of flags from the following list, +defined in +.In fcntl.h : +.Bl -tag -width indent +.It Dv AT_SYMLINK_NOFOLLOW +If +.Fa path +names a symbolic link, then the flags of the symbolic link are changed. +.It Dv AT_RESOLVE_BENEATH +Only walk paths below the directory specified by the +.Ar fd +descriptor. +See the description of the +.Dv O_RESOLVE_BENEATH +flag in the +.Xr open 2 +manual page. +.It Dv AT_EMPTY_PATH +If the +.Fa path +argument is an empty string, operate on the file or directory +referenced by the descriptor +.Fa fd . +If +.Fa fd +is equal to +.Dv AT_FDCWD , +operate on the current working directory. +.El +.Pp +If +.Fn chflagsat +is passed the special value +.Dv AT_FDCWD +in the +.Fa fd +parameter, the current working directory is used. +If also +.Fa atflag +is zero, the behavior is identical to a call to +.Fn chflags . +.Pp +The flags specified are formed by +.Em or Ns 'ing +the following values +.Pp +.Bl -tag -width ".Dv SF_IMMUTABLE" -compact -offset indent +.It Dv SF_APPEND +The file may only be appended to. +.It Dv SF_ARCHIVED +The file has been archived. +This flag means the opposite of the DOS, Windows and CIFS +FILE_ATTRIBUTE_ARCHIVE attribute. +This flag has been deprecated, and may be removed in a future release. +.It Dv SF_IMMUTABLE +The file may not be changed. +.It Dv SF_NOUNLINK +The file may not be renamed or deleted. +.It Dv SF_SNAPSHOT +The file is a snapshot file. +.It Dv UF_APPEND +The file may only be appended to. +.It Dv UF_ARCHIVE +The file needs to be archived. +This flag has the same meaning as the DOS, Windows and CIFS +FILE_ATTRIBUTE_ARCHIVE attribute. +Filesystems in FreeBSD may or may not have special handling for this flag. +For instance, ZFS tracks changes to files and will set this bit when a +file is updated. +UFS only stores the flag, and relies on the application to change it when +needed. +.It Dv UF_HIDDEN +The file may be hidden from directory listings at the application's +discretion. +The file has the DOS, Windows and CIFS FILE_ATTRIBUTE_HIDDEN attribute. +.It Dv UF_IMMUTABLE +The file may not be changed. +.It Dv UF_NODUMP +Do not dump the file. +.It Dv UF_NOUNLINK +The file may not be renamed or deleted. +.It Dv UF_OFFLINE +The file is offline, or has the Windows and CIFS FILE_ATTRIBUTE_OFFLINE +attribute. +Filesystems in FreeBSD store and display this flag, but do not provide any +special handling when it is set. +.It Dv UF_OPAQUE +The directory is opaque when viewed through a union stack. +.It Dv UF_READONLY +The file is read only, and may not be written or appended. +Filesystems may use this flag to maintain compatibility with the DOS, Windows +and CIFS FILE_ATTRIBUTE_READONLY attribute. +.It Dv UF_REPARSE +The file contains a Windows reparse point and has the Windows and CIFS +FILE_ATTRIBUTE_REPARSE_POINT attribute. +.It Dv UF_SPARSE +The file has the Windows FILE_ATTRIBUTE_SPARSE_FILE attribute. +This may also be used by a filesystem to indicate a sparse file. +.It Dv UF_SYSTEM +The file has the DOS, Windows and CIFS FILE_ATTRIBUTE_SYSTEM attribute. +Filesystems in FreeBSD may store and display this flag, but do not provide +any special handling when it is set. +.El +.Pp +If one of +.Dv SF_IMMUTABLE , SF_APPEND , +or +.Dv SF_NOUNLINK +is set a non-super-user cannot change any flags and even the super-user +can change flags only if securelevel is 0. +(See +.Xr init 8 +for details.) +.Pp +The +.Dv UF_IMMUTABLE , UF_APPEND , UF_NOUNLINK , UF_NODUMP , +and +.Dv UF_OPAQUE +flags may be set or unset by either the owner of a file or the super-user. +.Pp +The +.Dv SF_IMMUTABLE , SF_APPEND , SF_NOUNLINK , +and +.Dv SF_ARCHIVED +flags may only be set or unset by the super-user. +Attempts to toggle these flags by non-super-users are rejected. +These flags may be set at any time, but normally may only be unset when +the system is in single-user mode. +(See +.Xr init 8 +for details.) +.Pp +The implementation of all flags is filesystem-dependent. +See the description of the +.Dv UF_ARCHIVE +flag above for one example of the differences in behavior. +Care should be exercised when writing applications to account for +support or lack of support of these flags in various filesystems. +.Pp +The +.Dv SF_SNAPSHOT +flag is maintained by the system and cannot be toggled. +.Sh RETURN VALUES +.Rv -std +.Sh ERRORS +The +.Fn chflags +system call will fail if: +.Bl -tag -width Er +.It Bq Er ENOTDIR +A component of the path prefix is not a directory. +.It Bq Er ENAMETOOLONG +A component of a pathname exceeded 255 characters, +or an entire path name exceeded 1023 characters. +.It Bq Er ENOENT +The named file does not exist. +.It Bq Er EACCES +Search permission is denied for a component of the path prefix. +.It Bq Er ELOOP +Too many symbolic links were encountered in translating the pathname. +.It Bq Er EPERM +The effective user ID does not match the owner of the file and +the effective user ID is not the super-user. +.It Bq Er EPERM +One of +.Dv SF_IMMUTABLE , SF_APPEND , +or +.Dv SF_NOUNLINK +is set and the user is either not the super-user or +securelevel is greater than 0. +.It Bq Er EPERM +A non-super-user attempted to toggle one of +.Dv SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND , +or +.Dv SF_NOUNLINK . +.It Bq Er EPERM +An attempt was made to toggle the +.Dv SF_SNAPSHOT +flag. +.It Bq Er EROFS +The named file resides on a read-only file system. +.It Bq Er EFAULT +The +.Fa path +argument +points outside the process's allocated address space. +.It Bq Er EIO +An +.Tn I/O +error occurred while reading from or writing to the file system. +.It Bq Er EINTEGRITY +Corrupted data was detected while reading from the file system. +.It Bq Er EOPNOTSUPP +The underlying file system does not support file flags, or +does not support all of the flags set in +.Fa flags . +.El +.Pp +The +.Fn fchflags +system call will fail if: +.Bl -tag -width Er +.It Bq Er EBADF +The descriptor is not valid. +.It Bq Er EINVAL +The +.Fa fd +argument +refers to a socket, not to a file. +.It Bq Er EPERM +The effective user ID does not match the owner of the file and +the effective user ID is not the super-user. +.It Bq Er EPERM +One of +.Dv SF_IMMUTABLE , SF_APPEND , +or +.Dv SF_NOUNLINK +is set and the user is either not the super-user or +securelevel is greater than 0. +.It Bq Er EPERM +A non-super-user attempted to toggle one of +.Dv SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND , +or +.Dv SF_NOUNLINK . +.It Bq Er EPERM +An attempt was made to toggle the +.Dv SF_SNAPSHOT +flag. +.It Bq Er EROFS +The file resides on a read-only file system. +.It Bq Er EIO +An +.Tn I/O +error occurred while reading from or writing to the file system. +.It Bq Er EINTEGRITY +Corrupted data was detected while reading from the file system. +.It Bq Er EOPNOTSUPP +The underlying file system does not support file flags, or +does not support all of the flags set in +.Fa flags . +.It Bq Er ENOTCAPABLE +.Fa path +is an absolute path, +or contained a ".." component leading to a +directory outside of the directory hierarchy specified by +.Fa fd , +and the process is in capability mode or the +.Dv AT_RESOLVE_BENEATH +flag was specified. +.El +.Sh SEE ALSO +.Xr chflags 1 , +.Xr fflagstostr 3 , +.Xr strtofflags 3 , +.Xr init 8 , +.Xr mount_unionfs 8 +.Sh HISTORY +The +.Fn chflags +and +.Fn fchflags +system calls first appeared in +.Bx 4.4 . +The +.Fn lchflags +system call first appeared in +.Fx 5.0 . +The +.Fn chflagsat +system call first appeared in +.Fx 10.0 . |