fchflags (2)
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NAME
chflags lchflags fchflags chflagsat - set file flagsLIBRARY
Lb libcSYNOPSIS
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 atflagDESCRIPTION
The file whose name is given by Fa path or referenced by the descriptor Fa fd has its flags changed to Fa flags .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.
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 :
- AT_SYMLINK_NOFOLLOW
- If Fa path names a symbolic link, then the flags of the symbolic link are changed.
If Fn chflagsat is passed the special value 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 .
The flags specified are formed by or 'ing the following values
- SF_APPEND
- The file may only be appended to.
- 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- The file has been archived.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.
- SF_IMMUTABLE
- The file may not be changed.
- SF_NOUNLINK
- The file may not be renamed or deleted.
- SF_SNAPSHOT
- The file is a snapshot file.
- UF_APPEND
- The file may only be appended to.
- 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.
- 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.
- UF_IMMUTABLE
- The file may not be changed.
- UF_NODUMP
- Do not dump the file.
- UF_NOUNLINK
- The file may not be renamed or deleted.
- 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.
- UF_OPAQUE
- The directory is opaque when viewed through a union stack.
- 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.
- UF_REPARSE
- The file contains a Windows reparse point and has the Windows and CIFS FILE_ATTRIBUTE_REPARSE_POINT attribute.
- 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.
- 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.
If one of SF_IMMUTABLE , SF_APPEND or 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 init(8) for details.)
The UF_IMMUTABLE , UF_APPEND , UF_NOUNLINK , UF_NODUMP and UF_OPAQUE flags may be set or unset by either the owner of a file or the super-user.
The SF_IMMUTABLE , SF_APPEND , SF_NOUNLINK and 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 init(8) for details.)
The implementation of all flags is filesystem-dependent. See the description of the 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.
The SF_SNAPSHOT flag is maintained by the system and cannot be toggled.
RETURN VALUES
Rv -stdERRORS
The Fn chflags system call will fail if:- Bq Er ENOTDIR
- A component of the path prefix is not a directory.
- Bq Er ENAMETOOLONG
- A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters.
- Bq Er ENOENT
- The named file does not exist.
- Bq Er EACCES
- Search permission is denied for a component of the path prefix.
- Bq Er ELOOP
- Too many symbolic links were encountered in translating the pathname.
- 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.
- Bq Er EPERM
- One of SF_IMMUTABLE , SF_APPEND or SF_NOUNLINK is set and the user is either not the super-user or securelevel is greater than 0.
- Bq Er EPERM
- A non-super-user attempted to toggle one of SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND or SF_NOUNLINK
- Bq Er EPERM
- An attempt was made to toggle the SF_SNAPSHOT flag.
- Bq Er EROFS
- The named file resides on a read-only file system.
- Bq Er EFAULT
- The Fa path argument points outside the process's allocated address space.
- Bq Er EIO
- An I/O error occurred while reading from or writing to the file system.
- Bq Er EOPNOTSUPP
- The underlying file system does not support file flags, or does not support all of the flags set in Fa flags .
The Fn fchflags system call will fail if:
- Bq Er EBADF
- The descriptor is not valid.
- Bq Er EINVAL
- The Fa fd argument refers to a socket, not to a file.
- 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.
- Bq Er EPERM
- One of SF_IMMUTABLE , SF_APPEND or SF_NOUNLINK is set and the user is either not the super-user or securelevel is greater than 0.
- Bq Er EPERM
- A non-super-user attempted to toggle one of SF_ARCHIVED , SF_IMMUTABLE , SF_APPEND or SF_NOUNLINK
- Bq Er EPERM
- An attempt was made to toggle the SF_SNAPSHOT flag.
- Bq Er EROFS
- The file resides on a read-only file system.
- Bq Er EIO
- An I/O error occurred while reading from or writing to the file system.
- Bq Er EOPNOTSUPP
- The underlying file system does not support file flags, or does not support all of the flags set in Fa flags .