NAME

acl_get_fd, acl_get_fd_np, acl_get_file, acl_get_link_np —

get an ACL for a file

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

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

acl_t
acl_get_fd(int fd);

acl_t
acl_get_fd_np(int fd, acl_type_t type);

acl_t
acl_get_file(const char *path_p, acl_type_t type);

acl_t
acl_get_link_np(const char *path_p, acl_type_t type);

DESCRIPTION

The acl_get_fd(), acl_get_file(), acl_get_link_np(), and acl_get_fd_np() each allow the retrieval of an ACL from a file. The acl_get_fd() is a POSIX.1e call that allows the retrieval of an ACL of type ACL_TYPE_ACCESS from a file descriptor. The acl_get_fd_np() function is a non-portable form of acl_get_fd() that allows the retrieval of any type of ACL from a file descriptor. The acl_get_file() function is a POSIX.1e call that allows the retrieval of a specified type of ACL from a file by name; acl_get_link_np() is a non-portable variation on acl_get_file() which does not follow a symlink if the target of the call is a symlink.

These functions may cause memory to be allocated. The caller should free any releasable memory, when the new ACL is no longer required, by calling acl_free(3) with the (void *)acl_t as an argument.

The ACL in the working storage is an independent copy of the ACL associated with the object referred to by fd. The ACL in the working storage shall not participate in any access control decisions.

Valid values for the type argument are:

ACL_TYPE_ACCESS	POSIX.1e access ACL
ACL_TYPE_DEFAULT	POSIX.1e default ACL
ACL_TYPE_NFS4	NFSv4 ACL

The ACL returned will be branded accordingly.

IMPLEMENTATION NOTES

FreeBSD's support for POSIX.1e interfaces and features is still under development at this time.

RETURN VALUES

Upon successful completion, the function shall return a pointer to the ACL that was retrieved. Otherwise, a value of (acl_t)NULL shall be returned, and errno shall be set to indicate the error.

ERRORS

If any of the following conditions occur, the acl_get_fd() function shall return a value of (acl_t)NULL and set errno to the corresponding value:

[EACCES]: Search permission is denied for a component of the path prefix, or the object exists and the process does not have appropriate access rights.
[EBADF]: The fd argument is not a valid file descriptor.
[EINVAL]: The ACL type passed is invalid for this file object.
[ENAMETOOLONG]: A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters.
[ENOENT]: The named object does not exist, or the path_p argument points to an empty string.
[ENOMEM]: Insufficient memory available to fulfill request.
[EOPNOTSUPP]: The file system does not support ACL retrieval.

STANDARDS

POSIX.1e is described in IEEE POSIX.1e draft 17. Discussion of the draft continues on the cross-platform POSIX.1e implementation mailing list. To join this list, see the FreeBSD POSIX.1e implementation page for more information.

HISTORY

POSIX.1e support was introduced in FreeBSD 4.0, and development continues.

AUTHORS

Robert N M Watson