SETFACL(1) BSD General Commands Manual SETFACL(1)NAMEsetfacl — set ACL information
SYNOPSISsetfacl [-bdhkn] [-a position entries] [-m entries] [-M file]
[-x entries | position] [-X file] [file ...]
DESCRIPTION
The setfacl utility sets discretionary access control information on the
specified file(s). If no files are specified, or the list consists of
the only ‘-’, the file names are taken from the standard input.
The following options are available:
-a position entries
Modify the ACL on the specified files by inserting new ACL
entries specified in entries, starting at position position,
counting from zero. This option is only applicable to NFSv4
ACLs.
-b Remove all ACL entries except for the three required entries
(POSIX.1e ACLs) or six "canonical" entries (NFSv4 ACLs). If the
POSIX.1e ACL contains a “mask” entry, the permissions of the
“group” entry in the resulting ACL will be set to the permission
associated with both the “group” and “mask” entries of the cur‐
rent ACL.
-d The operations apply to the default ACL entries instead of access
ACL entries. Currently only directories may have default ACL's.
This option is not applicable to NFSv4 ACLs.
-h If the target of the operation is a symbolic link, perform the
operation on the symbolic link itself, rather than following the
link.
-k Delete any default ACL entries on the specified files. It is not
considered an error if the specified files do not have any
default ACL entries. An error will be reported if any of the
specified files cannot have a default entry (i.e. non-directo‐
ries). This option is not applicable to NFSv4 ACLs.
-m entries
Modify the ACL entries on the specified files by adding new
entries and modifying existing ACL entries with the ACL entries
specified in entries.
-M file
Modify the ACL entries on the specified files by adding new ACL
entries and modifying existing ACL entries with the ACL entries
specified in the file file. If file is -, the input is taken
from stdin.
-n Do not recalculate the permissions associated with the ACL mask
entry. This option is not applicable to NFSv4 ACLs.
-x entries | position
If entries is specified, remove the ACL entries specified there
from the access or default ACL of the specified files. Other‐
wise, remove entry at index position, counting from zero.
-X file
Remove the ACL entries specified in the file file from the access
or default ACL of the specified files.
The above options are evaluated in the order specified on the command-
line.
POSIX.1e ACL ENTRIES
A POSIX.1E ACL entry contains three colon-separated fields: an ACL tag,
an ACL qualifier, and discretionary access permissions:
ACL tag
The ACL tag specifies the ACL entry type and consists of one of
the following: “user” or ‘u’ specifying the access granted to the
owner of the file or a specified user; “group” or ‘g’ specifying
the access granted to the file owning group or a specified group;
“other” or ‘o’ specifying the access granted to any process that
does not match any user or group ACL entry; “mask” or ‘m’ speci‐
fying the maximum access granted to any ACL entry except the
“user” ACL entry for the file owner and the “other” ACL entry.
ACL qualifier
The ACL qualifier field describes the user or group associated
with the ACL entry. It may consist of one of the following: uid
or user name, gid or group name, or empty. For “user” ACL
entries, an empty field specifies access granted to the file
owner. For “group” ACL entries, an empty field specifies access
granted to the file owning group. “mask” and “other” ACL entries
do not use this field.
access permissions
The access permissions field contains up to one of each of the
following: ‘r’, ‘w’, and ‘x’ to set read, write, and execute per‐
missions, respectively. Each of these may be excluded or
replaced with a ‘-’ character to indicate no access.
A “mask” ACL entry is required on a file with any ACL entries other than
the default “user”, “group”, and “other” ACL entries. If the -n option
is not specified and no “mask” ACL entry was specified, the setfacl util‐
ity will apply a “mask” ACL entry consisting of the union of the permis‐
sions associated with all “group” ACL entries in the resulting ACL.
Traditional POSIX interfaces acting on file system object modes have mod‐
ified semantics in the presence of POSIX.1e extended ACLs. When a mask
entry is present on the access ACL of an object, the mask entry is sub‐
stituted for the group bits; this occurs in programs such as stat(1) or
ls(1). When the mode is modified on an object that has a mask entry, the
changes applied to the group bits will actually be applied to the mask
entry. These semantics provide for greater application compatibility:
applications modifying the mode instead of the ACL will see conservative
behavior, limiting the effective rights granted by all of the additional
user and group entries; this occurs in programs such as chmod(1).
ACL entries applied from a file using the -M or -X options shall be of
the following form: one ACL entry per line, as previously specified;
whitespace is ignored; any text after a ‘#’ is ignored (comments).
When POSIX.1e ACL entries are evaluated, the access check algorithm
checks the ACL entries in the following order: file owner, “user” ACL
entries, file owning group, “group” ACL entries, and “other” ACL entry.
Multiple ACL entries specified on the command line are separated by com‐
mas.
It is possible for files and directories to inherit ACL entries from
their parent directory. This is accomplished through the use of the
default ACL. It should be noted that before you can specify a default
ACL, the mandatory ACL entries for user, group, other and mask must be
set. For more details see the examples below. Default ACLs can be cre‐
ated by using -d.
NFSv4 ACL ENTRIES
An NFSv4 ACL entry contains four or five colon-separated fields: an ACL
tag, an ACL qualifier (only for “user” and “group” tags), discretionary
access permissions, ACL inheritance flags, and ACL type:
ACL tag
The ACL tag specifies the ACL entry type and consists of one of
the following: “user” or ‘u’ specifying the access granted to the
specified user; “group” or ‘g’ specifying the access granted to
the specified group; “owner@” specifying the access granted to
the owner of the file; “group@” specifying the access granted to
the file owning group; “everyone@” specifying everyone. Note
that “everyone@” is not the same as traditional Unix “other” - it
means, literally, everyone, including file owner and owning
group.
ACL qualifier
The ACL qualifier field describes the user or group associated
with the ACL entry. It may consist of one of the following: uid
or user name, or gid or group name. In entries whose tag type is
one of “owner@”, “group@”, or “everyone@”, this field is omitted
altogether, including the trailing comma.
access permissions
Access permissions may be specified in either short or long form.
Short and long forms may not be mixed. Permissions in long form
are separated by the ‘/’ character; in short form, they are con‐
catenated together. Valid permissions are:
Short Long
r read_data
w write_data
x execute
p append_data
d delete_child
D delete
a read_attributes
A write_attributes
R read_xattr
W write_xattr
c read_acl
C write_acl
o write_owner
S synchronize
ACL inheritance flags
Inheritance flags may be specified in either short or long form.
Short and long forms may not be mixed. Access flags in long form
are separated by the ‘/’ character; in short form, they are con‐
catenated together. Valid inheritance flags are:
Short Long
f file_inherit
d dir_inherit
i inherit_only
n no_propagate
Inheritance flags may be only set on directories.
ACL type
The ACL type field is either “allow” or “deny”.
ACL entries applied from a file using the -M or -X options shall be of
the following form: one ACL entry per line, as previously specified;
whitespace is ignored; any text after a ‘#’ is ignored (comments).
NFSv4 ACL entries are evaluated in their visible order.
Multiple ACL entries specified on the command line are separated by com‐
mas.
EXIT STATUS
The setfacl utility exits 0 on success, and >0 if an error occurs.
EXAMPLESsetfacl-d -m u::rwx,g::rx,o::rx,mask::rwx dir
setfacl-d -m g:admins:rwx dir
The first command sets the mandatory elements of the POSIX.1e default
ACL. The second command specifies that users in group admins can have
read, write, and execute permissions for directory named "dir". It
should be noted that any files or directories created underneath "dir"
will inherit these default ACLs upon creation.
setfacl-m u::rwx,g:mail:rw file
Sets read, write, and execute permissions for the file owner's POSIX.1e
ACL entry and read and write permissions for group mail on file.
setfacl-m owner@:rwxp::allow,g:mail:rwp::allow file
Semantically equal to the example above, but for NFSv4 ACL.
setfacl-M file1 file2
Sets/updates the ACL entries contained in file1 on file2.
setfacl-x g:mail:rw file
Remove the group mail POSIX.1e ACL entry containing read/write permis‐
sions from file.
setfacl-x0 file
Remove the first entry from the NFSv4 ACL from file.
setfacl-bn file
Remove all “access” ACL entries except for the three required from file.
getfacl file1 | setfacl-b -n -M - file2
Copy ACL entries from file1 to file2.
SEE ALSOgetfacl(1), acl(3), getextattr(8), setextattr(8), acl(9), extattr(9)STANDARDS
The setfacl utility is expected to be IEEE Std 1003.2c compliant.
HISTORY
Extended Attribute and Access Control List support was developed as part
of the TrustedBSD Project and introduced in FreeBSD 5.0. NFSv4 ACL sup‐
port was introduced in FreeBSD 8.1.
AUTHORS
The setfacl utility was written by Chris D. Faulhaber ⟨jedgar@fxp.org⟩.
NFSv4 ACL support was implemented by Edward Tomasz Napierala
⟨trasz@FreeBSD.org⟩.
BSD July 27, 2010 BSD
