NAME

       attr_set, attr_setf - set the value of a user attribute of a filesystem object

C SYNOPSIS

       #include <attr/attributes.h>

       int attr_set (const char *path, const char *attrname,
                     const char *attrvalue, const int valuelength,
                     int flags);

       int attr_setf (int fd, const char *attrname,
                      const char *attrvalue, const int valuelength,
                      int flags);

DESCRIPTION

       The  attr_set  and  attr_setf  functions provide a way to create attributes and set/change
       their values.

       Path points to a path name for a filesystem object, and fd refers to the  file  descriptor
       associated  with  a file.  If the attribute attrname does not exist, an attribute with the
       given name and value will be created and associated with that indicated filesystem object.
       If  an  attribute  with  that  name already exists on that filesystem object, the existing
       value is replaced with the new value given in this  call.   The  new  attribute  value  is
       copied from the attrvalue buffer for a total of valuelength bytes.  The flags argument can
       contain the following symbols bitwise OR'ed together:

       ATTR_ROOT
              Look for attrname in the root  address  space,  not  in  the  user  address  space.
              (limited to use by super-user only)

       ATTR_DONTFOLLOW
              Do  not  follow  symbolic links when resolving a path on an attr_set function call.
              The default is to follow symbolic links.

       ATTR_CREATE
              Return an error (EEXIST) if an attribute of the given name already  exists  on  the
              indicated  filesystem object, otherwise create an attribute with the given name and
              value.  This flag is used to implement a pure create operation, without  this  flag
              attr_set will create the attribute if it does not already exist.  An error (EINVAL)
              will be returned if both ATTR_CREATE and ATTR_REPLACE are set in the same call.

       ATTR_REPLACE
              Return an error (ENOATTR) if an attribute of the given name does not already  exist
              on  the  indicated  filesystem  object,  otherwise replace the existing attribute´s
              value with the given value.  This flag is used  to  implement  a  pure  replacement
              operation,  without  this  flag  attr_set  will create the attribute if it does not
              already exist.  An  error  (EINVAL)  will  be  returned  if  both  ATTR_CREATE  and
              ATTR_REPLACE are set in the same call.

       attr_set will fail if one or more of the following are true:

       [ENOATTR]        The  attribute name given is not associated with the indicated filesystem
                        object and the ATTR_REPLACE flag bit was set.

       [E2BIG]          The value of the given attribute is too large,  it  exceeds  the  maximum
                        allowable size of an attribute value.

       [EEXIST]         The  attribute  name  given  is  already  associated  with  the indicated
                        filesystem object and the ATTR_CREATE flag bit was set.

       [ENOENT]         The named file does not exist.

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

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

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

       [EINVAL]         A  bit  was  set in the flag argument that is not defined for this system
                        call, or both the ATTR_CREATE and ATTR_REPLACE flags bits were set.

       [EFAULT]         Path, attrname, or attrvalue points outside the allocated  address  space
                        of the process.

       [ELOOP]          A path name lookup involved too many symbolic links.

       [ENAMETOOLONG]   The  length  of  path  exceeds  {MAXPATHLEN},  or a pathname component is
                        longer than {MAXNAMELEN}.

       attr_setf will fail if:

       [ENOATTR]      The attribute name given is not associated with  the  indicated  filesystem
                      object and the ATTR_REPLACE flag bit was set.

       [E2BIG]        The  value  of  the  given  attribute  is too large, it exceeds the maximum
                      allowable size of an attribute value.

       [EEXIST]       The  attribute  name  given  is  already  associated  with  the   indicated
                      filesystem object and the ATTR_CREATE flag bit was set.

       [EINVAL]       A  bit  was  set  in  the flag argument that is not defined for this system
                      call, or both the ATTR_CREATE and ATTR_REPLACE flags bits were set,  or  fd
                      refers to a socket, not a file.

       [EFAULT]       Attrname,  or  attrvalue  points outside the allocated address space of the
                      process.

       [EBADF]        Fd does not refer to a valid descriptor.

DIAGNOSTICS

       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

SEE ALSO

       attr(1), attr_get(3), attr_list(3), attr_multi(3), and attr_remove(3).