.\" 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_EXTENDED_FILE 3
.Os "Linux ACL"
.Sh NAME
.Nm acl_extended_file, acl_extended_file_nofollow
.Nd test for information in ACLs by file name
.Sh LIBRARY
Linux Access Control Lists library (libacl, \-lacl).
.Sh SYNOPSIS
.In sys/types.h
.In acl/libacl.h
.Ft int
.Fn acl_extended_file "const char *path_p"
.Ft int
.Fn acl_extended_file_nofollow "const char *path_p"
.Sh DESCRIPTION
The
.Fn acl_extended_file
function returns
.Li 1
if the file or directory referred to by the argument
.Va path_p
is associated with an extended access ACL, or if the directory referred to by
.Va path_p
is associated with a default ACL. The function returns
.Li 0
if the file has neither an extended access ACL nor a default ACL.
.Pp
An extended ACL is an ACL that contains entries other than the three
required entries of tag types ACL_USER_OBJ, ACL_GROUP_OBJ and ACL_OTHER.
If the result of the
.Fn acl_extended_file
function for a file object is
.Li 0 ,
then ACLs define no discretionary access rights other than those
already defined by the traditional file permission bits.
.Pp
Access to the file object may be further restricted by other
mechanisms, such as Mandatory Access Control schemes. The
.Xr access 2
system call can be used to check whether a given type of access to a file
object would be granted.
.Pp
.Fn acl_extended_file_nofollow
is identical to
.Fn acl_extended_file ,
except in the case of a symbolic link, where the link itself is interrogated,
not the file that it refers to.  Since symbolic links have no ACL themselves,
the operation is supposed to fail on them.
.Sh RETURN VALUE
If successful, the
.Fn acl_extended_file
function returns
.Li 1
if the file object referred to by
.Va path_p
has an extended access ACL or a default ACL, and
.Li 0
if the file object referred to by
.Va path_p
has neither an extended access ACL nor a default ACL. Otherwise, the value
.Li -1
is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
If any of the following conditions occur, the
.Fn acl_extended_file
function returns
.Li -1
and sets
.Va errno
to the corresponding value:
.Bl -tag -width Er
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.It Bq Er ENAMETOOLONG
The length of the argument
.Va path_p
is too long.
.It Bq Er ENOENT
The named object does not exist or the argument
.Va path_p
points to an empty string.
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er ENOTSUP
The file system on which the file identified by
.Va path_p
is located does not support ACLs, or ACLs are disabled.
.El
.Sh STANDARDS
This is a non-portable, Linux specific extension to the ACL manipulation
functions defined in IEEE Std 1003.1e draft 17 (\(lqPOSIX.1e\(rq, abandoned).
.Sh SEE ALSO
.Xr access 2 ,
.Xr acl_get_file 3 ,
.Xr acl 5
.Sh AUTHOR
Written by
.An "Andreas Gruenbacher" Aq andreas.gruenbacher@gmail.com .