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2.\" Copyright (c) 2001 Robert N. M. Watson
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26.Dd August 22, 2001
27.Dt VACCESS_ACL_POSIX1E 9
28.Os
29.Sh NAME
30.Nm vaccess_acl_posix1e
31.Nd generate a POSIX.1e ACL access control decision using vnode parameters
32.Sh SYNOPSIS
33.In sys/param.h
34.In sys/vnode.h
35.In sys/acl.h
36.Ft int
37.Fo vaccess_acl_posix1e
38.Fa "enum vtype type"
39.Fa "uid_t file_uid"
40.Fa "gid_t file_gid"
41.Fa "struct acl *acl"
42.Fa "accmode_t accmode"
43.Fa "struct ucred *cred"
44.Fa "int *privused"
45.Fc
46.Sh DESCRIPTION
47This call implements the logic for the
48.Ux
49discretionary file security model
50with POSIX.1e ACL extensions.
51It accepts the vnodes type
52.Fa type ,
53owning UID
54.Fa file_uid ,
55owning GID
56.Fa file_gid ,
57access ACL for the file
58.Fa acl ,
59desired access mode
60.Fa accmode ,
61requesting credential
62.Fa cred ,
63and an optional call-by-reference
64.Vt int
65pointer returning whether or not
66privilege was required for successful evaluation of the call; the
67.Fa privused
68pointer may be set to
69.Dv NULL
70by the caller in order not to be informed of
71privilege information, or it may point to an integer that will be set to
721 if privilege is used, and 0 otherwise.
73.Pp
74This call is intended to support implementations of
75.Xr VOP_ACCESS 9 ,
76which will use their own access methods to retrieve the vnode properties,
77and then invoke
78.Fn vaccess_acl_posix1e
79in order to perform the actual check.
80Implementations of
81.Xr VOP_ACCESS 9
82may choose to implement additional security mechanisms whose results will
83be composed with the return value.
84.Pp
85The algorithm used by
86.Fn vaccess_acl_posix1e
87is based on the POSIX.1e ACL evaluation algorithm.
88The algorithm selects a
89.Em matching
90entry from the access ACL, which may
91then be composed with an available ACL mask entry, providing
92.Ux
93security compatibility.
94.Pp
95Once appropriate protections are selected for the current credential,
96the requested access mode, in combination with the vnode type, will be
97compared with the discretionary rights available for the credential.
98If the rights granted by discretionary protections are insufficient,
99then super-user privilege, if available for the credential, will also be
100considered.
101.Sh RETURN VALUES
102.Fn vaccess_acl_posix1e
103will return 0 on success, or a non-zero error value on failure.
104.Sh ERRORS
105.Bl -tag -width Er
106.It Bq Er EACCES
107Permission denied.
108An attempt was made to access a file in a way forbidden by its file access
109permissions.
110.It Bq Er EPERM
111Operation not permitted.
112An attempt was made to perform an operation limited to processes with
113appropriate privileges or to the owner of a file or other resource.
114.El
115.Sh SEE ALSO
116.Xr vaccess 9 ,
117.Xr vnode 9 ,
118.Xr VOP_ACCESS 9
119.Sh AUTHORS
120This manual page and the current implementation of
121.Fn vaccess_acl_posix1e
122were written by
123.An Robert Watson .
124.Sh BUGS
125This manual page should include a full description of the POSIX.1e ACL
126evaluation algorithm, or cross reference another page that does.
127