Manpages - acl_extended_file.3

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

The

function returns

if the file or directory referred to by the argument

is associated with an extended access ACL, or if the directory referred to by

is associated with a default ACL. The function returns

if the file has neither an extended access ACL nor a default ACL.

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

function for a file object is

then ACLs define no discretionary access rights other than those already defined by the traditional file permission bits.

Access to the file object may be further restricted by other mechanisms, such as Mandatory Access Control schemes. The

system call can be used to check whether a given type of access to a file object would be granted.

is identical to

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.

If successful, the

function returns

if the file object referred to by

has an extended access ACL or a default ACL, and

if the file object referred to by

has neither an extended access ACL nor a default ACL. Otherwise, the value

is returned and the global variable

is set to indicate the error.

If any of the following conditions occur, the

function returns

and sets

to the corresponding value:

Search permission is denied for a component of the path prefix.

The length of the argument

is too long.

The named object does not exist or the argument

points to an empty string.

A component of the path prefix is not a directory.

The file system on which the file identified by

is located does not support ACLs, or ACLs are disabled.

This is a non-portable, Linux specific extension to the ACL manipulation functions defined in IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned).

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