setacl(C)

setacl -- modify Access Control List (ACL) for file(s)

Synopsis

setacl [-r] -s acl_entries file ...

setacl [-r] [-m acl_entries] -d acl_entries file ...

setacl [-r] -f acl_file file ...

Description

For each file specified, setacl will either replace its entire ACL, including the default ACL on a directory, or it will add, modify, or delete one or more ACL entries, including default entries on directories.

The -s option will set the ACL to the entries specified on the command line. The -f option will set the ACL the entries contained within the file acl_file. The -d option will delete one or more specified entries from the file's ACL. The -m option will add or modify one or more specified ACL entries.

One of the options -s, -m, -d, or -f must be specified. If -s or -f are specified, other options are invalid. The -m and -d options may be combined.

For the -m and -s options, acl_entries are one or more comma separated ACL entries selected from the following list. For the -f option, acl_file must contain ACL entries, one to a line, selected from the same list. Default entries may only be specified for directories. Bold face indicates that characters must be typed as specified, brackets denote optional characters, and italicized characters are to be specified by the user.

   u[ser]::operm | perm
   u[ser]:uid:operm | perm
   g[roup]::operm | perm
   g[roup]:gid:operm | perm
   c[lass]:operm | perm
   o[ther]:operm | perm
   d[efault]:u[ser]::operm | perm
   d[efault]:u[ser]:uid:operm | perm
   d[efault]:g[roup]::operm | perm
   d[efault]:g[roup]:gid:operm | perm
   d[efault]:c[lass]:operm | perm
   d[efault]:o[ther]:operm | perm

For the -d option, acl_entries are one or more comma separated ACL entries without permissions, selected from the following list.

NOTE: The entries for file owner, owning group, and others may not be deleted.

   u[ser]:uid
   g[roup]:gid
   d[efault]:u[ser]:
   d[efault]:u[ser]:uid
   d[efault]:g[roup]:
   d[efault]:g[roup]:gid
   d[efault]:c[lass]:
   d[efault]:o[ther]:

In the above lists, the user specifies the following:

perm: is a permissions string composed of the characters ``r'' (read), ``w'' (write), and ``x'' (execute), each of which may appear at most one time, in any order. The character - may be specified as a placeholder.
operm: is the octal representation of the above permissions, with 7 representing all permissions, or rwx, and 0 representing no permissions, or ---.
uid: is a login name or user ID.
gid: is a group name or group ID.

The options have the following meanings:

-r

Recalculate the group class entry so as to ensure that permissions granted in the additional ACL entries will actually be granted. If the -r option is specified, the value specified in the ``class'' entry is ignored.

-s

Set a file's ACL. All old ACL entries are removed, and replaced with the newly specified ACL. There must be exactly one ``user'' entry specified for the owner of the file, exactly one ``group'' entry specified for the owning group of the file, exactly one ``class'' entry specified for the file group class, and exactly one ``other'' entry specified. There may be additional ``user'' ACL entries and additional ``group'' ACL entries specified, but there may not be duplicate additional ``user'' ACL entries with the same uid, or duplicate additional ``group'' ACL entries with the same gid. If the file is a directory, default ACL entries may be specified. There may be at most one default ``user'' entry for the owner of the file, at most one default ``group'' entry for the owning group of the file, atmost one default ``class'' entry for the file group class, and at most one default ``other'' entry for other. There may be additional default ``user'' entries and additional default ``group'' entries specified, but there may not be duplicate additional default ``user'' entries with the same uid, or duplicate additional default ``group'' entries with the same gid. An entry with no permissions will result in the specified uid or gid being denied access to the file. The entries need not be in order. They will be sorted by the command before being applied to the file.

-m

Add one or more new ACL entries to the file, and/or change one or more existing ACL entries on the file. If an entry already exists for a specified uid or gid the specified permissions will replace the current permissions. If an entry does not exist for the specified uid or gid, an entry will be created.

-d

Delete one or more existing ACL entries from the file. The entries for the file owner, the owning group, and others may not be deleted from the ACL.

NOTE: Deleting an entry does not necessarily have the same effect as removing all permissions from the entry.

Specifically, deleting an entry for a specific user would cause that user's permissions to be determined by the ``other'' entry (or the owning ``group'' entry, if the user is in that group).

-f

Set 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 specified as acl_file. The character "#" in acl_file may be used to indicate a comment. All characters, starting with the ``#'', until the end of the line, will be ignored.

NOTE: If the acl_file has been created as the output of the getacl command, any effective permissions, which will have been written with a preceding "#", will also be ignored.

When the setacl command is used, it may result in changes to the file permission bits. When the ``user'' ACL entry for the file owner is changed, the file owner permission bits will be modified. When the ``other'' ACL entry is changed, the file other permission bits will be modified. When additional ``user'' ACL entries and/or any ``group'' ACL entries are set or modified, the file group class permission bits will be modified to reflect the maximum permissions allowed by the additional ``user'' entries and all the ``group'' entries.

If an ACL does not contain additional ``user'' and additional ``group'' entries, the permissions in the ``group'' entry for the object owning ``group'' and the ``class'' entry must be the same. Therefore, if the -d option is specified and results in no additional user entries and no additional group entries, the ``class'' entry permissions will be set equal to the permissions of the owning group entry (this is equivalent to using the -r option).

A directory may contain default ACL entries. If a file is created in a directory which contains default ACL entries, the entries will be added to the newly created file.

NOTE: The default permissions specified for the file owner, file owning group, and others, will be constrained by the umask and the mode specified in the file creation call.

If an ACL does not contain additional ``default:user'' and additional ``default:group'' entries and a ``default:group'' entry is specified for the object owning group, then a ``default:class'' entry must also be specified, and the permissions in the ``default:group'' entry for the object owning group and the permissions for the ``default:class'' entry must be the same.

This command may be executed on a file system that does not support ACLs, to set the permissions for the three base entries for the file owner, file owning group, and others. Additional entries and default entries will not be allowed in this case.

Files

/etc/passwd: user IDs
/etc/group: group IDs

Examples

To add one ACL entry to file filea , giving user ``archer'' read permission only, type:

   setacl -m user:archer:r-- filea

If an entry for user ``archer'' already exists, this command will set the permissions in that entry to r--.

To replace the entire ACL for file filea, adding entries for users ``archer'', and ``fletcher'', allowing read/write access, an entry for the file owner allowing all access, an entry for the file group allowing read access only, and an entry for others disallowing all access, type:

   setacl -r -s user::rwx,user:archer:rw-,user:fletcher:rw-,\
   	group::r--,class:---,other:--- filea

NOTE: Following this command, the file permission bits would be set to -rwxrw----

Even though the file owning group has only read permission, the maximum permissions available to all additional ``user'' ACL entries, and all ``group'' ACL entries, are read and write, since the two additional ``user'' entries both specify these permissions.

To set the same ACL on file filea as in the above example, using the -f option, type:

   setacl -r -f filea.acl filea

with file filea.acl edited to contain:

   user::rwx
   user:archer:rw-
   user:fletcher:rw-
   group::r--
   other:---

Because the -r option was specified, no ``class'' entry was needed. If a class entry had been present it would have been ignored.

References

acl(S), aclsort(S), chmod(C), getacl(C), ls(C)