illumos: manual page: setfacl.1

SETFACL(1) User Commands SETFACL(1)

NAME

setfacl - modify the Access Control List (ACL) for a file or files

SYNOPSIS

setfacl [-r] -s acl_entries file

setfacl [-r] -md acl_entries file

setfacl [-r] -f acl_file file

DESCRIPTION

For each file specified, setfacl either replaces its entire ACL,
including the default ACL on a directory, or it adds, modifies, or
deletes one or more ACL entries, including default entries on
directories.

The setfacl utility can only manipulate POSIX-draft ACLs. See acl(7) for
a description of the difference between the older POSIX-draft ACLs and
the newer NFSv4 ACLs. The chmod(1) utility can be used to manipulate
ACLs on all types of file system.

When the setfacl command is used, it can result in changes to the file
permission bits. When the user ACL entry for the file owner is changed,
the file owner class permission bits are modified. When the group ACL
entry for the file group class is changed, the file group class
permission bits are modified. When the other ACL entry is changed, the
file other class permission bits are modified.

If you use the chmod(1) command to change the file group owner
permissions on a file with ACL entries, both the file group owner
permissions and the ACL mask are changed to the new permissions. Be aware
that the new ACL mask permissions can change the effective permissions
for additional users and groups who have ACL entries on the file.

A directory can contain default ACL entries. If a file or directory is
created in a directory that contains default ACL entries, the newly
created file has permissions generated according to the intersection of
the default ACL entries and the permissions requested at creation time.
The umask(1) are not applied if the directory contains default ACL
entries. If a default ACL is specified for a specific user (or users),
the file has a regular ACL created. Otherwise, only the mode bits are
initialized according to the intersection described above. The default
ACL should be thought of as the maximum discretionary access permissions
that can be granted.

Use the setfacl command to set ACLs on files in a UFS file system, which
supports POSIX-draft ACLS (or aclent_t style ACLs). Use the chmod command
to set ACLs on files in a ZFS file system, which supports NFSv4-style
ACLS (or ace_t style ACLs).

acl_entries Syntax
For the -m and -s options, acl_entries are one or more comma-separated
ACL entries.

An ACL entry consists of the following fields separated by colons:

entry_type
Type of ACL entry on which to set file permissions. For
example, entry_type can be user (the owner of a file) or
mask (the ACL mask).

uid or gid
User name or user identification number. Or, group name or
group identification number.

perms
Represents the permissions that are set on entry_type.
perms can be indicated by the symbolic characters rwx or a
number (the same permissions numbers used with the chmod
command).

The following table shows the valid ACL entries (default entries can only
be specified for directories):

ACL Entry Description
--------------------------------------------------------------------
u[ser]::perms File owner permissions.
g[roup]::perms File group owner permissions.
o[ther]:perms Permissions for users other than the
file owner or members of file group
owner.
m[ask]:perms The ACL mask. The mask entry
indicates the maximum permissions
allowed for users (other than the
owner) and for groups. The mask is a
quick way to change permissions on
all the users and groups.
u[ser]:uid:perms Permissions for a specific user. For
uid, you can specify either a user
name or a numeric UID.
g[roup]:gid:perms Permissions for a specific group. For
gid, you can specify either a group
name or a numeric GID.
d[efault]:u[ser]::perms Default file owner permissions.
d[efault]:g[roup]::perms Default file group owner permissions.
d[efault]:o[ther]:perms Default permissions for users other
than the file owner or members of the
file group owner.
d[efault]:m[ask]:perms Default ACL mask.
d[efault]:u[ser]:uid:perms Default permissions for a specific
user. For uid, you can specify either
a user name or a numeric UID.
d[efault]:g[roup]:gid:perms Default permissions for a specific
group. For gid, you can specify
either a group name or a numeric GID.

For the -d option, acl_entries are one or more comma-separated ACL
entries without permissions. Notice that the entries for file owner, file
group owner, ACL mask, and others can not be deleted.

OPTIONS

The options have the following meaning:

-d acl_entries
Deletes one or more entries from the file. The entries
for the file owner, the file group owner, and others
can not be deleted from the ACL. Notice that deleting
an entry does not necessarily have the same effect as
removing all permissions from the entry.

-f acl_file
Sets a file's ACL with the ACL entries contained in the
file named acl_file. The same constraints on specified
entries hold as with the -s option. The entries are not
required to be in any specific order in the file. Also,
if you specify a dash (-) for acl_file, standard input
is used to set the file's ACL.

The character # in acl_file can be used to indicate a
comment. All characters, starting with the # until the
end of the line, are ignored. Notice that if the
acl_file has been created as the output of the
getfacl(1) command, any effective permissions, which
follow a #, are ignored.

-m acl_entries
Adds one or more new ACL entries to the file, and/or
modifies one or more existing ACL entries on the file.
If an entry already exists for a specified uid or gid,
the specified permissions replace the current
permissions. If an entry does not exist for the
specified uid or gid, an entry is created. When using
the -m option to modify a default ACL, you must specify
a complete default ACL (user, group, other, mask, and
any additional entries) the first time.

-r
Recalculates the permissions for the ACL mask entry.
The permissions specified in the ACL mask entry are
ignored and replaced by the maximum permissions
necessary to grant the access to all additional user,
file group owner, and additional group entries in the
ACL. The permissions in the additional user, file group
owner, and additional group entries are left unchanged.

-s acl_entries
Sets a file's ACL. All old ACL entries are removed and
replaced with the newly specified ACL. The entries need
not be in any specific order. They are sorted by the
command before being applied to the file.

Required entries:

o Exactly one user entry specified for the
file owner.

o Exactly one group entry for the file group
owner.

o Exactly one other entry specified.
If there are additional user and group entries:

o Exactly one mask entry specified for the ACL
mask that indicates the maximum permissions
allowed for users (other than the owner) and
groups.

o Must not be duplicate user entries with the
same uid.

o Must not be duplicate group entries with the
same gid.
If file is a directory, the following default ACL
entries can be specified:

o Exactly one default user entry for the file
owner.

o Exactly one default group entry for the file
group owner.

o Exactly one default mask entry for the ACL
mask.

o Exactly one default other entry.
There can be additional default user entries and
additional default group entries specified, but there
can not be duplicate additional default user entries
with the same uid, or duplicate default group entries
with the same gid.

EXAMPLES

Example 1: Adding read permission only

The following example adds one ACL entry to file abc, which gives user
shea read permission only.

setfacl -m user:shea:r-- abc

Example 2: Replacing a file's entire ACL

The following example replaces the entire ACL for the file abc, which
gives shea read access, the file owner all access, the file group owner
read access only, the ACL mask read access only, and others no access.

setfacl -s user:shea:rwx,user::rwx,group::rw-,mask:r--,other:--- abc

Notice that after this command, the file permission bits are rwxr-----.
Even though the file group owner was set with read/write permissions, the
ACL mask entry limits it to have only read permission. The mask entry
also specifies the maximum permissions available to all additional user
and group ACL entries. Once again, even though the user shea was set with
all access, the mask limits it to have only read permission. The ACL mask
entry is a quick way to limit or open access to all the user and group
entries in an ACL. For example, by changing the mask entry to read/write,
both the file group owner and user shea would be given read/write access.

Example 3: Setting the same ACL on two files

The following example sets the same ACL on file abc as the file xyz.

getfacl xyz | setfacl -f - abc

FILES

/etc/passwd
password file

/etc/group
group file