.\" Copyright (c) 2010 Joerg Sonnenberger
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.Dd February 21, 2010
.Dt ARCHIVE_ENTRY_ACL 3
.Os
.Sh NAME
.Nm archive_entry_acl_add_entry ,
.Nm archive_entry_acl_add_entry_w ,
.Nm archive_entry_acl_clear ,
.Nm archive_entry_acl_count ,
.Nm archive_entry_acl_next ,
.Nm archive_entry_acl_next_w ,
.Nm archive_entry_acl_reset ,
.Nm archive_entry_acl_text_w
.Nd functions for manipulating Access Control Lists in archive entry descriptions
.Sh SYNOPSIS
.In archive_entry.h
.Ft void
.Fo archive_entry_acl_add_entry
.Fa "struct archive_entry *a"
.Fa "int type"
.Fa "int permset"
.Fa "int tag"
.Fa "int qualifier"
.Fa "const char *name"
.Fc
.Ft void
.Fo archive_entry_acl_add_entry_w
.Fa "struct archive_entry *a"
.Fa "int type"
.Fa "int permset"
.Fa "int tag"
.Fa "int qualifier"
.Fa "const wchar_t *name"
.Fc
.Ft void
.Fn archive_entry_acl_clear "struct archive_entry *a"
.Ft int
.Fn archive_entry_acl_count "struct archive_entry *a" "int type"
.Ft int
.Fo archive_entry_acl_next
.Fa "struct archive_entry *a"
.Fa "int type"
.Fa "int *ret_type"
.Fa "int *ret_permset"
.Fa "int *ret_tag"
.Fa "int *ret_qual"
.Fa "const char **ret_name"
.Fc
.Ft int
.Fo archive_entry_acl_next_w
.Fa "struct archive_entry *a"
.Fa "int type"
.Fa "int *ret_type"
.Fa "int *ret_permset"
.Fa "int *ret_tag"
.Fa "int *ret_qual"
.Fa "const wchar_t **ret_name"
.Fc
.Ft int
.Fn archive_entry_acl_reset "struct archive_entry *a" "int type"
.Ft const wchar_t *
.Fn archive_entry_acl_text_w "struct archive_entry *a" "int flags"
.\" enum?
.Sh DESCRIPTION
An
.Dq Access Control List
is a generalisation of the classic Unix permission system.
The ACL interface of
.Nm libarchive
is derived from the POSIX.1e draft, but restricted to simplify dealing
with practical implementations in various Operating Systems and archive formats.
.Pp
An ACL consists of a number of independent entries.
Each entry specifies the permission set as bitmask of basic permissions.
Valid permissions are:
.Bl -tag -offset indent -compact -width "ARCHIVE_ENTRY_ACL_EXECUTE"
.It Dv ARCHIVE_ENTRY_ACL_EXECUTE
.It Dv ARCHIVE_ENTRY_ACL_WRITE
.It Dv ARCHIVE_ENTRY_ACL_READ
.El
The permissions correspond to the normal Unix permissions.
.Pp
The tag specifies the principal to which the permission applies.
Valid values are:
.Bl -tag -offset indent -compact -width "ARCHIVE_ENTRY_ACL_GROUP_OBJ"
.It Dv ARCHIVE_ENTRY_ACL_USER
The user specified by the name field.
.It Dv ARCHIVE_ENTRY_ACL_USER_OBJ
The owner of the file.
.It Dv ARCHIVE_ENTRY_ACL_GROUP
The group specied by the name field.
.It Dv ARCHIVE_ENTRY_ACL_GROUP_OBJ
The group who owns the file.
.It Dv ARCHIVE_ENTRY_ACL_MASK
The maximum permissions to be obtained via group permissions.
.It Dv ARCHIVE_ENTRY_ACL_OTHER
Any principal who doesn't have a user or group entry.
.El
The principals
.Dv ARCHIVE_ENTRY_ACL_USER_OBJ ,
.Dv ARCHIVE_ENTRY_ACL_GROUP_OBJ
and
.Dv ARCHIVE_ENTRY_ACL_OTHER
are equivalent to user, group and other in the classic Unix permission
model and specify non-extended ACL entries.
.Pp
All files have an access ACL
.Pq Dv ARCHIVE_ENTRY_ACL_TYPE_ACCESS .
This specifies the permissions required for access to the file itself.
Directories have an additional ACL
.Pq Dv ARCHIVE_ENTRY_ACL_TYPE_DEFAULT ,
which controls the initial access ACL for newly created directory entries.
.Pp
.Fn archive_entry_acl_add_entry
and
.Fn archive_entry_acl_add_entry_w
add a single ACL entry.
For the access ACL and non-extended principals, the classic Unix permissions
are updated.
.Pp
.Fn archive_entry_acl_clear
removes all ACL entries and resets the enumeration pointer.
.Pp
.Fn archive_entry_acl_count
counts the ACL entries that have the given type mask.
.Fa type
can be the bitwise-or of
.Dv ARCHIVE_ENTRY_ACL_TYPE_ACCESS
and
.Dv ARCHIVE_ENTRY_ACL_TYPE_DEFAULT .
If
.Dv ARCHIVE_ENTRY_ACL_TYPE_ACCESS
is included and at least one extended ACL entry is found,
the three non-extened ACLs are added.
.Pp
.Fn archive_entry_acl_next
and
.Fn archive_entry_acl_next_w
return the next entry of the ACL list.
This functions may only be called after
.Fn archive_entry_acl_reset
has indicated the presence of extended ACL entries.
.Pp
.Fn archive_entry_acl_reset
prepare reading the list of ACL entries with
.Fn archive_entry_acl_next
or
.Fn archive_entry_acl_next_w .
The function returns either 0, if no non-extended ACLs are found.
In this case, the access permissions should be obtained by
.Xr archive_entry_mode 3
or set using
.Xr chmod 2 .
Otherwise, the function returns the same value as
.Fn archive_entry_acl_count .
.Pp
.Fn archive_entry_acl_text_w
converts the ACL entries for the given type mask into a wide string.
In addition to the normal type flags,
.Dv ARCHIVE_ENTRY_ACL_STYLE_EXTRA_ID
and
.Dv ARCHIVE_ENTRY_ACL_STYLE_MARK_DEFAULT
can be specified to further customize the result.
The returned long string is valid until the next call to
.Fn archive_entry_acl_clear ,
.Fn archive_entry_acl_add_entry ,
.Fn archive_entry_acl_add_entry_w
or
.Fn archive_entry_acl_text_w .
.Sh RETURN VALUES
.Fn archive_entry_acl_count
and
.Fn archive_entry_acl_reset
returns the number of ACL entries that match the given type mask.
If the type mask includes
.Dv ARCHIVE_ENTRY_ACL_TYPE_ACCESS
and at least one extended ACL entry exists, the three classic Unix
permissions are counted.
.Pp
.Fn archive_entry_acl_next
and
.Fn archive_entry_acl_next_w
return
.Dv ARCHIVE_OK
on success,
.Dv ARCHIVE_EOF
if no more ACL entries exist
and
.Dv ARCHIVE_WARN
if
.Fn archive_entry_acl_reset
has not been called first.
.Pp
.Fn archive_entry_text_w
returns a wide string representation of the ACL entrise matching the
given type mask.
The returned long string is valid until the next call to
.Fn archive_entry_acl_clear ,
.Fn archive_entry_acl_add_entry ,
.Fn archive_entry_acl_add_entry_w
or
.Fn archive_entry_acl_text_w .
.Sh SEE ALSO
.Xr archive 3 ,
.Xr archive_entry 3
.Sh BUGS
.Dv ARCHIVE_ENTRY_ACL_STYLE_EXTRA_ID
and
.Dv ARCHIVE_ENTRY_ACL_STYLE_MARK_DEFAULT
are not documented.