CHFLAGS(2)

NAME
chflags, chflagsat, fchflags - set file flags

SYNOPSIS
#include <sys/stat.h>
int
chflags(const char *path, unsigned int flags);
int
fchflags(int fd, unsigned int flags);
#include <sys/stat.h>
#include <fcntl.h>
int
chflagsat(int fd, const char *path, unsigned int flags, int atflags);

DESCRIPTION
The file whose name is given by path or referenced by the descriptor fd has its flags changed to flags.

The flags are the bitwise OR of zero or more of the following values:

UF_NODUMP
    Do not dump the file.
UF_IMMUTABLE
    The file may not be changed.
UF_APPEND
    The file may only be appended to.
SF_ARCHIVED
    The file may be archived.
SF_IMMUTABLE
    The file may not be changed.
SF_APPEND
    The file may only be appended to.

The UF_IMMUTABLE and UF_APPEND flags may be set or unset by either the owner of a file or the superuser.

The SF_ARCHIVED, SF_IMMUTABLE and SF_APPEND flags may only be set or unset by the superuser. They 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 chflagsat() function is equivalent to chflags() except in the case where path specifies a relative path. In this case the file to be changed is determined relative to the directory associated with the file descriptor fd instead of the current working directory.

If chflagsat() is passed the special value AT_FDCWD (defined in <fcntl.h>) in the fd parameter, the current working directory is used. If atflags is also zero, the behavior is identical to a call to chflags().

The atflags argument is the bitwise OR of zero or more of the following values:

AT_SYMLINK_NOFOLLOW
    If path names a symbolic link, then the flags of the symbolic link are changed.

The fchflags() function is equivalent to chflags() except that the file whose flags are changed is specified by the file descriptor fd.

RETURN VALUES

ERRORS
chflags() will fail if:

[ENOTDIR]
    A component of the path prefix is not a directory.

[ENAMETOOLONG]
    A component of a pathname exceeded NAME_MAX characters, or an entire pathname (including the terminating NUL) exceeded PATH_MAX bytes.

[ENOENT]
    The named file does not exist.

[EACCES]
    Search permission is denied for a component of the path prefix.

[ELOOP]
    Too many symbolic links were encountered in translating the pathname.

[EPERM]
    The effective user ID does not match the owner of the file and the effective user ID is not the superuser, or the effective user ID is not the superuser and at least one of the super-user-only flags for the named file would be changed.

[EOPNOTSUPP]
    The named file resides on a file system that does not support file flags.

[EROFS]
    The named file resides on a read-only file system.

[EFAULT]
    path points outside the process's allocated address space.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

[EINVAL]
    The flags value is invalid.

[EINVAL]
    The descriptor references a block or character device and the effective user ID is not the superuser.

fchflags() will fail if:

[EBADF]
    The descriptor is not valid.

[EINVAL]
    fd refers to a socket, not to a file.

[EINVAL]
    The descriptor references a block or character device and the effective user ID is not the superuser.

[EINVAL]
    The flags value is invalid.

[EPERM]
    The effective user ID does not match the owner of the file and the effective user ID is not the superuser, or the effective user ID is not the superuser and at least one of the super-user-only flags for the named file would be changed.

[EOPNOTSUPP]
    The named file resides on a file system that does not support file flags.

[EROFS]
    The file resides on a read-only file system.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

SEE ALSO
chflags(1), init(8)

HISTORY
The chflags() and fchflags() functions first appeared in 4.4BSD. The chflagsat() function first appeared in FreeBSD 10.0. It was added to OpenBSD in OpenBSD 5.7.