NAME

     acl_extended_file, acl_extended_file_nofollow — test for information in ACLs by file name

LIBRARY

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

SYNOPSIS

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

     int
     acl_extended_file(const char *path_p);

     int
     acl_extended_file_nofollow(const char *path_p);

DESCRIPTION

     The acl_extended_file() function returns 1 if the file or directory referred to by the argument path_p is
     associated with an extended access ACL, or if the directory referred to by path_p is associated with a
     default ACL. The function returns 0 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 acl_extended_file() function for a file
     object is 0, 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 access(2) system call can be used to check whether a given type of access to a file object
     would be granted.

     acl_extended_file_nofollow() is identical to 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.

RETURN VALUE

     If successful, the acl_extended_file() function returns 1 if the file object referred to by path_p has an
     extended access ACL or a default ACL, and 0 if the file object referred to by path_p has neither an
     extended access ACL nor a default ACL. Otherwise, the value -1 is returned and the global variable errno is
     set to indicate the error.

ERRORS

     If any of the following conditions occur, the acl_extended_file() function returns -1 and sets errno to the
     corresponding value:

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

     [ENAMETOOLONG]     The length of the argument path_p is too long.

     [ENOENT]           The named object does not exist or the argument path_p points to an empty string.

     [ENOTDIR]          A component of the path prefix is not a directory.

     [ENOTSUP]          The file system on which the file identified by path_p is located does not support ACLs,
                        or ACLs are disabled.

STANDARDS

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

SEE ALSO

     access(2), acl_get_file(3), acl(5)

AUTHOR

     Written by Andreas Gruenbacher <a.gruenbacher@bestbits.at>.