.\" Access Control Lists manual pages
.\"
.\" (C) 2002 Andreas Gruenbacher, <a.gruenbacher@bestbits.at>
.\"
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.Dd March 23, 2002
.Dt ACL_CALC_MASK 3
.Os "Linux ACL"
.Sh NAME
.Nm acl_calc_mask
.Nd calculate the file group class mask
.Sh LIBRARY
Linux Access Control Lists library (libacl, \-lacl).
.Sh SYNOPSIS
.In sys/types.h
.In sys/acl.h
.Ft int
.Fn acl_calc_mask "acl_t *acl_p"
.Sh DESCRIPTION
The
.Fn acl_calc_mask
function calculates and sets the permissions associated with the ACL_MASK
ACL entry of the ACL referred to by
.Va acl_p .
The value of the new permissions is the union of the permissions
granted by all entries of tag type ACL_GROUP, ACL_GROUP_OBJ, or ACL_USER.
If the ACL referred to by
.Va acl_p
already contains an ACL_MASK entry, its permissions are overwritten;
if it does not contain an ACL_MASK entry, one is added.
.Pp
If the ACL referred to by
.Va acl_p
does not contain enough space for the new ACL entry, then additional working
storage may be allocated. If the working storage cannot be increased in the
current location, then it may be relocated and the previous working storage
is released and a pointer to the new working storage is returned via
.Va acl_p .
.Pp
The order of existing entries in the ACL is undefined after this function.
.Pp
Any existing ACL entry descriptors that refer to entries in the ACL continue to
refer to those entries. Any existing ACL pointers that refer to the ACL
referred to by
.Va acl_p
continue to refer to the ACL.
.\" <AG>
.\" Conflict between requirements:
.\" (a) ACL may be relocated,
.\" (b) all pointers remain valid.
.\" </AG>
.Sh RETURN VALUE
.Rv -std acl_calc_mask
.Sh ERRORS
If any of the following conditions occur, the
.Fn acl_calc_mask
function returns
.Li -1
and sets
.Va errno
to the corresponding value:
.Bl -tag -width Er
.It Bq Er EINVAL
The argument
.Va acl
is not a valid pointer to an ACL.
.It Bq Er ENOMEM
The
.Fn acl_calc_mask
function is unable to allocate the memory required for an ACL_MASK ACL entry.
.El
.Sh STANDARDS
IEEE Std 1003.1e draft 17 (\(lqPOSIX.1e\(rq, abandoned)
.Sh SEE ALSO
.Xr acl_check 3 ,
.Xr acl_get_entry 3 ,
.Xr acl_valid 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 a.gruenbacher@bestbits.at .
