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CHFLAGS(2)               DragonFly System Calls Manual              CHFLAGS(2)


NAME

     chflags, lchflags, fchflags, chflagsat - set file flags


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <sys/stat.h>
     #include <unistd.h>

     int
     chflags(const char *path, unsigned long flags);

     int
     lchflags(const char *path, unsigned long flags);

     int
     fchflags(int fd, unsigned long flags);

     int
     chflagsat(int fd, const char *path, unsigned long flags, int atflag);


DESCRIPTION

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

     The lchflags() system call is like chflags() except in the case where the
     named file is a symbolic link, in which case lchflags() will change the
     flags of the link itself, rather than the file it points to.

     The chflagsat() is equivalent to either chflags() or lchflags() depending
     on the atflag 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.  The values for the atflag are constructed by a
     bitwise-inclusive OR of flags from the following list, defined in
     <fcntl.h>:

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

     If chflagsat() is passed the special value AT_FDCWD in the fd parameter,
     the current working directory is used.  If also atflag is zero, the
     behavior is identical to a call to chflags().

     The flags specified are formed by or'ing 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.
           UF_OPAQUE         The directory is opaque when viewed through a
                             union stack.
           UF_NOUNLINK       The file may not be renamed or deleted.
           UF_NOHISTORY      Do not retain history for file.
           UF_CACHE          Enable swapcache(8) data caching.  The flag is
                             recursive and need only be set on a top-level
                             directory.
           SF_ARCHIVED       The file may be archived.
           SF_IMMUTABLE      The file may not be changed.
           SF_APPEND         The file may only be appended to.
           SF_NOUNLINK       The file may not be renamed or deleted.
           SF_NOHISTORY      Do not retain history for file.
           SF_NOCACHE        Disable swapcache(8) data caching.  The flag is
                             recursive and need only be set on a top-level
                             directory.

     The "UF_" prefixed flags may be set or unset by either the owner of a
     file or the super-user.

     The "SF_" prefixed flags may only be set or unset by the super-user.
     Attempts by the non-super-user to set the super-user only flags are
     silently ignored.  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.)


RETURN VALUES

     Upon successful completion, the value 0 is returned; otherwise the
     value -1 is returned and the global variable errno is set to indicate the
     error.


ERRORS

     Chflags() will fail if:

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

     [ENAMETOOLONG]     A component of a pathname exceeded 255 characters, or
                        an entire path name exceeded 1023 characters.

     [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 super-user.

     [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.

     [EOPNOTSUPP]       The underlying file system does not support file
                        flags.

     Fchflags() will fail if:

     [EBADF]            The descriptor is not valid.

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

     [EPERM]            The effective user ID does not match the owner of the
                        file and the effective user ID is not the super-user.

     [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.

     [EOPNOTSUPP]       The underlying file system does not support file
                        flags.


SEE ALSO

     chflags(1), fflagstostr(3), strtofflags(3), init(8), swapcache(8)


HISTORY

     The chflags and fchflags functions first appeared in 4.4BSD.

DragonFly 5.7-DEVELOPMENT       October 6, 2019      DragonFly 5.7-DEVELOPMENT

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