1.\" Copyright (c) 1996
2.\" Mike Pritchard <mpp@FreeBSD.org>. All rights reserved.
3.\"
4.\" Copyright (c) 1992, 1993, 1994
5.\" The Regents of the University of California. All rights reserved.
6.\" All rights reserved.
7.\"
8.\" This code is derived from software donated to Berkeley by
9.\" Jan-Simon Pendry.
10.\"
11.\" Redistribution and use in source and binary forms, with or without
12.\" modification, are permitted provided that the following conditions
13.\" are met:
14.\" 1. Redistributions of source code must retain the above copyright
15.\" notice, this list of conditions and the following disclaimer.
16.\" 2. Redistributions in binary form must reproduce the above copyright
17.\" notice, this list of conditions and the following disclaimer in the
18.\" documentation and/or other materials provided with the distribution.
19.\" 3. All advertising materials mentioning features or use of this software
20.\" must display the following acknowledgement:
21.\" This product includes software developed by the University of
22.\" California, Berkeley and its contributors.
23.\" 4. Neither the name of the University nor the names of its contributors
24.\" may be used to endorse or promote products derived from this software
25.\" without specific prior written permission.
26.\"
27.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37.\" SUCH DAMAGE.
38.\"
| 1.\" Copyright (c) 1996
2.\" Mike Pritchard <mpp@FreeBSD.org>. All rights reserved.
3.\"
4.\" Copyright (c) 1992, 1993, 1994
5.\" The Regents of the University of California. All rights reserved.
6.\" All rights reserved.
7.\"
8.\" This code is derived from software donated to Berkeley by
9.\" Jan-Simon Pendry.
10.\"
11.\" Redistribution and use in source and binary forms, with or without
12.\" modification, are permitted provided that the following conditions
13.\" are met:
14.\" 1. Redistributions of source code must retain the above copyright
15.\" notice, this list of conditions and the following disclaimer.
16.\" 2. Redistributions in binary form must reproduce the above copyright
17.\" notice, this list of conditions and the following disclaimer in the
18.\" documentation and/or other materials provided with the distribution.
19.\" 3. All advertising materials mentioning features or use of this software
20.\" must display the following acknowledgement:
21.\" This product includes software developed by the University of
22.\" California, Berkeley and its contributors.
23.\" 4. Neither the name of the University nor the names of its contributors
24.\" may be used to endorse or promote products derived from this software
25.\" without specific prior written permission.
26.\"
27.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37.\" SUCH DAMAGE.
38.\"
|
39.\" $Id$
| 39.\" $Id: fdesc.5,v 1.3 1997/03/07 03:27:59 jmg Exp $
|
40.\"
41.Dd December 14, 1996
42.Dt fdesc 5
43.Os BSD 4.4
44.Sh NAME
45.Nm fdesc
46.Nd file-descriptor file system
47.Sh SYNOPSIS
48fdesc /dev fdesc rw 0 0
49.Sh DESCRIPTION
50The file-descriptor file system, or
51.Nm fdesc ,
52provides access to the per-process file descriptor
53namespace in the global filesystem namespace.
54The conventional mount point is
55.Pa /dev
56and the filesystem should be union mounted in order to augment,
57rather than replace, the existing entries in
58.Pa /dev .
59.Pp
60The contents of the mount point are
61.Pa fd ,
62.Pa stderr ,
63.Pa stdin ,
64.Pa stdout
65and
66.Pa tty .
67.Pp
68.Pa fd
69is a directory whose contents
70appear as a list of numbered files
71which correspond to the open files of the process reading the
72directory.
73The files
74.Pa /dev/fd/0
75through
76.Pa /dev/fd/#
77refer to file descriptors which can be accessed through the file
78system.
79If the file descriptor is open and the mode the file is being opened
80with is a subset of the mode of the existing descriptor, the call:
81.Bd -literal -offset indent
82fd = open("/dev/fd/0", mode);
83.Ed
84.Pp
85and the call:
86.Bd -literal -offset indent
87fd = fcntl(0, F_DUPFD, 0);
88.Ed
89.Pp
90are equivalent.
91.Pp
92The files
93.Pa /dev/stdin ,
94.Pa /dev/stdout
95and
96.Pa /dev/stderr
97appear as symlinks to the relevant entry in the
98.Pa /dev/fd
99sub-directory.
100Opening them is equivalent to the following calls:
101.Bd -literal -offset indent
102fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
103fd = fcntl(STDOUT_FILENO, F_DUPFD, 0);
104fd = fcntl(STDERR_FILENO, F_DUPFD, 0);
105.Ed
106.Pp
107Flags to the
108.Xr open 2
109call other than
110.Dv O_RDONLY ,
111.Dv O_WRONLY
112and
113.Dv O_RDWR
114are ignored.
115.Pp
116The
117.Pa /dev/tty
118entry is an indirect reference to the current process's controlling terminal.
119It appears as a named pipe (FIFO) but behaves in exactly the same way as
120the real controlling terminal device.
121.Sh FILES
122.Bl -tag -width /dev/stderr -compact
123.It Pa /dev/fd/#
124.It Pa /dev/stdin
125.It Pa /dev/stdout
126.It Pa /dev/stderr
127.It Pa /dev/tty
128.El
129.Sh SEE ALSO
130.Xr tty 4 ,
131.Xr mount_devfs 8 ,
132.Xr mount_fdesc 8
133.Sh HISTORY
134The
135.Nm
136filesystem first appeared in
137.Bx 4.4 . The
138.Nm
139manual page first appeared in
140.Fx 2.2 .
| 40.\"
41.Dd December 14, 1996
42.Dt fdesc 5
43.Os BSD 4.4
44.Sh NAME
45.Nm fdesc
46.Nd file-descriptor file system
47.Sh SYNOPSIS
48fdesc /dev fdesc rw 0 0
49.Sh DESCRIPTION
50The file-descriptor file system, or
51.Nm fdesc ,
52provides access to the per-process file descriptor
53namespace in the global filesystem namespace.
54The conventional mount point is
55.Pa /dev
56and the filesystem should be union mounted in order to augment,
57rather than replace, the existing entries in
58.Pa /dev .
59.Pp
60The contents of the mount point are
61.Pa fd ,
62.Pa stderr ,
63.Pa stdin ,
64.Pa stdout
65and
66.Pa tty .
67.Pp
68.Pa fd
69is a directory whose contents
70appear as a list of numbered files
71which correspond to the open files of the process reading the
72directory.
73The files
74.Pa /dev/fd/0
75through
76.Pa /dev/fd/#
77refer to file descriptors which can be accessed through the file
78system.
79If the file descriptor is open and the mode the file is being opened
80with is a subset of the mode of the existing descriptor, the call:
81.Bd -literal -offset indent
82fd = open("/dev/fd/0", mode);
83.Ed
84.Pp
85and the call:
86.Bd -literal -offset indent
87fd = fcntl(0, F_DUPFD, 0);
88.Ed
89.Pp
90are equivalent.
91.Pp
92The files
93.Pa /dev/stdin ,
94.Pa /dev/stdout
95and
96.Pa /dev/stderr
97appear as symlinks to the relevant entry in the
98.Pa /dev/fd
99sub-directory.
100Opening them is equivalent to the following calls:
101.Bd -literal -offset indent
102fd = fcntl(STDIN_FILENO, F_DUPFD, 0);
103fd = fcntl(STDOUT_FILENO, F_DUPFD, 0);
104fd = fcntl(STDERR_FILENO, F_DUPFD, 0);
105.Ed
106.Pp
107Flags to the
108.Xr open 2
109call other than
110.Dv O_RDONLY ,
111.Dv O_WRONLY
112and
113.Dv O_RDWR
114are ignored.
115.Pp
116The
117.Pa /dev/tty
118entry is an indirect reference to the current process's controlling terminal.
119It appears as a named pipe (FIFO) but behaves in exactly the same way as
120the real controlling terminal device.
121.Sh FILES
122.Bl -tag -width /dev/stderr -compact
123.It Pa /dev/fd/#
124.It Pa /dev/stdin
125.It Pa /dev/stdout
126.It Pa /dev/stderr
127.It Pa /dev/tty
128.El
129.Sh SEE ALSO
130.Xr tty 4 ,
131.Xr mount_devfs 8 ,
132.Xr mount_fdesc 8
133.Sh HISTORY
134The
135.Nm
136filesystem first appeared in
137.Bx 4.4 . The
138.Nm
139manual page first appeared in
140.Fx 2.2 .
|
141.Sh AUTHOR
| 141.Sh AUTHORS
|
142The
143.Nm
| 142The
143.Nm
|
144manaul page was written by Mike Pritchard <mpp@FreeBSD.org>,
| 144manual page was written by
145.An Mike Pritchard Aq mpp@FreeBSD.org ,
|
145and was based on the
146.Xr mount_fdesc 8
| 146and was based on the
147.Xr mount_fdesc 8
|
147manual page written by Jan-Simon Pendry.
| 148manual page written by
149.An Jan-Simon Pendry .
|
| |