.\" Access Control Lists manual pages
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.\" (C) 2002 Andreas Gruenbacher, <andreas.gruenbacher@gmail.com>
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.Dd March 23, 2002
.Dt ACL_GET_QUALIFIER 3
.Os "Linux ACL"
.Sh NAME
.Nm acl_get_qualifier
.Nd retrieve the qualifier from an ACL entry
.Sh LIBRARY
Linux Access Control Lists library (libacl, \-lacl).
.Sh SYNOPSIS
.In sys/types.h
.In sys/acl.h
.Ft void *
.Fn acl_get_qualifier "acl_entry_t entry_d"
.Sh DESCRIPTION
The
.Fn acl_get_qualifier
function retrieves the qualifier from the ACL entry indicated by the argument
.Va entry_d
into working storage and returns a pointer to that storage.
.Pp
If the value of the tag type in the ACL entry referred to by
.Va entry_d
is ACL_USER, then the value returned by
.Fn acl_get_qualifier
is a pointer to type
.Va uid_t .
If the value of the tag type in the ACL entry referred to by
.Va entry_d
is ACL_GROUP, then the value returned by
.Fn acl_get_qualifier
is a pointer to type
.Va gid_t .
If the tag type in the ACL entry referred to by
.Va entry_d
is a tag type for which a qualifier is not supported,
.Fn acl_get_qualifier
returns a value of
.Li (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.
.Pp
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
.Fn acl_free
with the
.Va void *
value returned by
.Fn acl_get_qualifier
as an argument.
.Pp
The argument
.Va entry_d
and any other ACL entry descriptors that refer to entries within the ACL
containing the entry referred to by
.Va entry_d
continue to refer to those entries. The order of all existing
entries in the ACL containing the entry referred to by
.Va entry_d
remains unchanged.
.Sh 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
.Li (void *)NULL
is returned and
.Va errno
is set appropriately.
.Sh ERRORS
If any of the following conditions occur, the
.Fn acl_get_qualifier
function returns
.Li (void *)NULL
and sets
.Va errno
to the corresponding value:
.Bl -tag -width Er
.It Bq Er EINVAL
The argument
.Va entry_d
is not a valid descriptor for an ACL entry.
.Pp
The value of the tag type in the ACL entry referenced by the argument
.Va entry_d
is neither ACL_USER nor ACL_GROUP.
.It Bq Er ENOMEM
The value to be returned requires more memory than is allowed by the hardware or system-imposed memory management constraints.
.El
.Sh STANDARDS
IEEE Std 1003.1e draft 17 (\(lqPOSIX.1e\(rq, abandoned)
.Sh SEE ALSO
.Xr acl_create_entry 3 ,
.Xr acl_free 3 ,
.Xr acl_get_entry 3 ,
.Xr acl_get_permset 3 ,
.Xr acl_get_tag_type 3 ,
.Xr acl_set_permset 3 ,
.Xr acl_set_qualifier 3 ,
.Xr acl_set_tag_type 3 ,
.Xr acl 5
.Sh AUTHOR
Derived from the FreeBSD manual pages written by
.An "Robert N M Watson" Aq rwatson@FreeBSD.org ,
and adapted for Linux by
.An "Andreas Gruenbacher" Aq andreas.gruenbacher@gmail.com .