xref: /freebsd/lib/libsys/revoke.2 (revision 1edb7116)
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31.Dd January 25, 2016
32.Dt REVOKE 2
33.Os
34.Sh NAME
35.Nm revoke
36.Nd revoke file access
37.Sh LIBRARY
38.Lb libc
39.Sh SYNOPSIS
40.In unistd.h
41.Ft int
42.Fn revoke "const char *path"
43.Sh DESCRIPTION
44The
45.Fn revoke
46system call invalidates all current open file descriptors in the system
47for the file named by
48.Fa path .
49Subsequent operations on any such descriptors
50fail, with the exceptions that a
51.Fn read
52from a character device file which has been revoked
53returns a count of zero (end of file),
54and a
55.Fn close
56system call will succeed.
57If the file is a special file for a device which is open,
58the device close function
59is called as if all open references to the file had been closed
60using a special close method which does not block.
61.Pp
62Access to a file may be revoked only by its owner or the super user.
63The
64.Fn revoke
65system call is currently supported only for block and character special
66device files.
67It is normally used to prepare a terminal device for a new login session,
68preventing any access by a previous user of the terminal.
69.Sh RETURN VALUES
70.Rv -std revoke
71.Sh ERRORS
72Access to the named file is revoked unless one of the following:
73.Bl -tag -width Er
74.It Bq Er ENOTDIR
75A component of the path prefix is not a directory.
76.It Bq Er ENAMETOOLONG
77A component of a pathname exceeded 255 characters,
78or an entire path name exceeded 1024 characters.
79.It Bq Er ENOENT
80The named file or a component of the path name does not exist.
81.It Bq Er EACCES
82Search permission is denied for a component of the path prefix.
83.It Bq Er ELOOP
84Too many symbolic links were encountered in translating the pathname.
85.It Bq Er EFAULT
86The
87.Fa path
88argument
89points outside the process's allocated address space.
90.It Bq Er EINVAL
91The implementation does not support the
92.Fn revoke
93operation on the named file.
94.It Bq Er EPERM
95The caller is neither the owner of the file nor the super user.
96.El
97.Sh SEE ALSO
98.Xr revoke 1 ,
99.Xr close 2
100.Sh HISTORY
101The
102.Fn revoke
103system call first appeared in
104.Bx 4.3 Reno .
105.Sh BUGS
106The non-blocking close method is only correctly implemented for
107terminal devices.
108