NAME

       acl_get_qualifier — retrieve the qualifier from an ACL entry

LIBRARY

       Linux Access Control Lists library (libacl, -lacl).

SYNOPSIS

       #include <sys/types.h>
       #include <sys/acl.h>

       void *
       acl_get_qualifier(acl_entry_t entry_d);

DESCRIPTION

       The  acl_get_qualifier()  function  retrieves  the qualifier from the ACL entry indicated by the argument
       entry_d into working storage and returns a pointer to that storage.

       If the value of the tag type in the ACL entry referred to by entry_d is ACL_USER, then the value returned
       by acl_get_qualifier() is a pointer to type uid_t.  If the value  of  the  tag  type  in  the  ACL  entry
       referred  to by entry_d is ACL_GROUP, then the value returned by acl_get_qualifier() is a pointer to type
       gid_t.  If the tag type in the ACL entry referred to by entry_d is a tag type for which  a  qualifier  is
       not  supported,  acl_get_qualifier()  returns  a value of (void *)NULL and the function fails. Subsequent
       operations using the returned pointer operate on an independent copy of the qualifier in working storage,
       and will not change the qualifier of the ACL entry.

       This function may cause memory to be allocated. The caller should free any releasable  memory,  when  the
       new  qualifier  is  no  longer  required,  by  calling  acl_free()  with  the  void  *  value returned by
       acl_get_qualifier() as an argument.

       The argument entry_d and any other ACL entry descriptors that refer to entries within the ACL  containing
       the entry referred to by entry_d continue to refer to those entries. The order of all existing entries in
       the ACL containing the entry referred to by entry_d remains unchanged.

RETURN VALUE

       On  success,  the  function  returns  a  pointer to the tag qualifier that was retrieved into ACL working
       storage. On error, a value of (void *)NULL is returned and errno is set appropriately.

ERRORS

       If any of the following conditions occur, the acl_get_qualifier() function returns (void *)NULL and  sets
       errno to the corresponding value:

       [EINVAL]           The argument entry_d is not a valid descriptor for an ACL entry.

                          The  value  of  the  tag  type  in the ACL entry referenced by the argument entry_d is
                          neither ACL_USER nor ACL_GROUP.

       [ENOMEM]           The value to be returned requires more memory than  is  allowed  by  the  hardware  or
                          system-imposed memory management constraints.

STANDARDS

       IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned)

SEE ALSO

       acl_create_entry(3),     acl_free(3),    acl_get_entry(3),    acl_get_permset(3),    acl_get_tag_type(3),
       acl_set_permset(3), acl_set_qualifier(3), acl_set_tag_type(3), acl(5)

AUTHOR

       Derived from the FreeBSD manual pages written by Robert N M Watson <rwatson@FreeBSD.org>, and adapted for
       Linux by Andreas Gruenbacher <andreas.gruenbacher@gmail.com>.

Linux ACL                                        March 23, 2002                             ACL_GET_QUALIFIER(3)