acl, facl - get or set a file's Access Control List (ACL)
#include <sys/acl.h>
int acl(char *pathp, int cmd, int nentries, void *aclbufp);
int facl(int fildes, int cmd, int nentries, void *aclbufp);
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.
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.
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.
See attributes(7) for descriptions of the following
attributes:
| ATTRIBUTE
TYPE |
ATTRIBUTE VALUE |
| Interface Stability |
Evolving |