ACL(2) System Calls ACL(2)

NAME

acl, facl - get or set a file's Access Control List (ACL)

SYNOPSIS

#include <sys/acl.h>

int acl(char *pathp, int cmd, int nentries, void *aclbufp);


int facl(int fildes, int cmd, int nentries, void *aclbufp);

DESCRIPTION

The acl() and facl() functions get or set the ACL of a file whose
name is given by pathp or referenced by the open file descriptor
fildes. The nentries argument specifies how many ACL entries fit into
buffer aclbufp. The acl() function is used to manipulate ACL on file
system objects.


The following types are supported for aclbufp:

aclent_t
Used by the UFS file system.


ace_t
Used by the ZFS and NFSv4 file systems.


The following values for cmd are supported:

SETACL
nentries aclent_t ACL entries, specified in buffer
aclbufp, are stored in the file's ACL. All
directories in the path name must be searchable.


GETACL
Buffer aclbufp is filled with the file's aclent_t
ACL entries. Read access to the file is not
required, but all directories in the path name must
be searchable.


GETACLCNT
The number of entries in the file's aclent_t ACL is
returned. Read access to the file is not required,
but all directories in the path name must be
searchable.


ACE_SETACL
nentries ace_t ACL entries, specified in buffer
aclbufp, are stored in the file's ACL. All
directories in the path name must be searchable.
Write ACL access is required to change the file's
ACL.


ACE_GETACL
Buffer aclbufp is filled with the file's ace_t ACL
entries. Read access to the file is required and all
directories in the path name must be searchable.


ACE_GETACLCNT
The number of entries in the file's ace_t ACL is
returned. Read access to the file is required and
all directories in the path name must be searchable.

RETURN VALUES

Upon successful completion, acl() and facl() return 0 if cmd is
SETACL or ACE_SETACL. If cmd is GETACL, GETACLCNT, ACE_GETACL or
ACE_GETACLCNT, the number of ACL entries is returned. Otherwise, -1
is returned and errno is set to indicate the error.

ERRORS

The acl() function will fail if:

EACCES
The caller does not have access to a component of the
pathname.


EFAULT
The pathp or aclbufp argument points to an illegal
address.


EINVAL
The cmd argument is not GETACL, SETACL, ACE_GETACL,
GETACLCNT, or ACE_GETACLCNT; the cmd argument is SETACL
and nentries is less than 3; or the cmd argument is
SETACL or ACE_SETACL and the ACL specified in aclbufp is
not valid.


EIO
A disk I/O error has occurred while storing or
retrieving the ACL.


ENOENT
A component of the path does not exist.


ENOSPC
The cmd argument is GETACL and nentries is less than the
number of entries in the file's ACL, or the cmd argument
is SETACL and there is insufficient space in the file
system to store the ACL.


ENOSYS
The cmd argument is SETACL or ACE_SETACL and the file
specified by pathp resides on a file system that does not
support ACLs, or the acl() function is not supported by
this implementation.


ENOTDIR
A component of the path specified by pathp is not a
directory, or the cmd argument is SETACL or ACE_SETACL
and an attempt is made to set a default ACL on a file type
other than a directory.


ENOTSUP
The cmd argument is GETACL, but the ACL is composed of
ace_t entries, and the ACL cannot be translated into
aclent_t form.

The cmd argument is ACE_SETACL, but the underlying
filesystem only supports ACLs composed of aclent_t entries
and the ACL could not be translated into aclent_t form.


EPERM
The effective user ID does not match the owner of the file
and the process does not have appropriate privilege.


EROFS
The cmd argument is SETACL or ACE_SETACL and the file
specified by pathp resides on a file system that is
mounted read-only.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+---------------------+------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------------+------------------+
|Interface Stability | Evolving |
+---------------------+------------------+

SEE ALSO

getfacl(1), setfacl(1), aclcheck(3SEC), aclsort(3SEC)

January 10, 2007 ACL(2)