freebsd/share/man/man4/snp.4

.\"
.\" $FreeBSD$
.\"
.Dd November 5, 2008
.Dt SNP 4
.Os
.Sh NAME
.Nm snp
.Nd tty snoop interface
.Sh SYNOPSIS
.In sys/snoop.h
.Ft int
.Fn ioctl fd SNPSTTY &dev
.Ft int
.Fn ioctl fd SNPGTTY &dev
.Ft int
.Fn ioctl fd FIONREAD &result
.Sh DESCRIPTION
.Pa /dev/snp
is a snoop device which allows users to attach to any tty
and watch activities on it.
The kernel must be compiled with
.Cd "device snp" ,
or the
.Nm
module must be loaded,
for these devices to be available.
.Pp
To associate a given
.Nm
device with a tty to be observed, open the
.Nm
device and a tty device, and then issue the
.Dv SNPSTTY
ioctl on
.Nm
device.
The argument passed to the
.Xr ioctl 2
is the address of a variable of type
.Vt int ,
holding the file descriptor of a tty device.
To detach the
.Nm
device from a tty use a pointer to a value of
\-1.
.Pp
The
.Dv SNPGTTY
ioctl returns information about the current tty attached to
the open
.Nm
device.
.Pp
The
.Dv FIONREAD
ioctl returns a positive value equal to the number of characters
in a read buffer.
Special values defined are:
.Bl -tag -width ".Dv SNP_TTYCLOSE"
.It Dv SNP_OFLOW
device overflow occurred, device detached.
.It Dv SNP_TTYCLOSE
tty not attached.
.It Dv SNP_DETACH
.Nm
device has been detached by user or tty device has been closed
and detached.
.El
.Sh SEE ALSO
.Xr pty 4 ,
.Xr sio 4 ,
.Xr kldload 8 ,
.Xr watch 8
.Sh HISTORY
The
.Nm
device first appeared in
.Fx 2.1 .
In
.Fx 8.0
the
.Nm
driver was rewritten to work with the replaced TTY subsystem.
.Sh AUTHORS
The author of the current implementation is
.An Ed Schouten Aq ed@FreeBSD.org .
Previous versions of
.Nm
were based on code written by
.An Ugen J.S. Antsilevich Aq ugen@NetVision.net.il .
.Sh BUGS
This version of
.Nm
does not return proper error codes when calling
.Dv FIONREAD .
It also does not allow
.Dv SNPSTTY
to detach itself from the TTY.
Clean up man page 1995-02-23 01:25:48 +00:00			`.\"`
$Id$ -> $FreeBSD$ 1999-08-28 00:22:10 +00:00			`.\" $FreeBSD$`
Clean up man page 1995-02-23 01:25:48 +00:00			`.\"`
Reintroduce the snp(4) driver. Because the TTY hooks interface was not finished when I imported the MPSAFE TTY layer, I had to disconnect the snp(4) driver. This snp(4) implementation has been sitting in my P4 branch for some time now. Unfortunately it still doesn't use the same error handling as snp(4) (returning codes through FIONREAD), but it should already be usable. I'm committing this to SVN, hoping someone else could polish off its rough edges. It's always better than having a broken driver sitting in the tree. 2008-11-05 15:04:03 +00:00			`.Dd November 5, 2008`
Clean up man page 1995-02-23 01:25:48 +00:00			`.Dt SNP 4`
mdoc(7) police: removed HISTORY info from the .Os call. 2001-07-10 15:31:11 +00:00			`.Os`
Move ipfirewall.4 & snp.4 facility manpage to share/man/man4 1995-02-17 18:48:36 +00:00			`.Sh NAME`
Clean up man page 1995-02-23 01:25:48 +00:00			`.Nm snp`
			`.Nd tty snoop interface`
Move ipfirewall.4 & snp.4 facility manpage to share/man/man4 1995-02-17 18:48:36 +00:00			`.Sh SYNOPSIS`
mdoc(7) police: Use the new .In macro for #include statements. 2001-10-01 16:09:29 +00:00			`.In sys/snoop.h`
Clean up man page 1995-02-23 01:25:48 +00:00			`.Ft int`
Update to reflect new calling conventions 1995-02-25 20:15:20 +00:00			`.Fn ioctl fd SNPSTTY &dev`
Clean up man page 1995-02-23 01:25:48 +00:00			`.Ft int`
Update to reflect new calling conventions 1995-02-25 20:15:20 +00:00			`.Fn ioctl fd SNPGTTY &dev`
Clean up man page 1995-02-23 01:25:48 +00:00			`.Ft int`
Update to reflect new calling conventions 1995-02-25 20:15:20 +00:00			`.Fn ioctl fd FIONREAD &result`
Move ipfirewall.4 & snp.4 facility manpage to share/man/man4 1995-02-17 18:48:36 +00:00			`.Sh DESCRIPTION`
Convert the snp(4) driver to use cdevpriv. Now we have a single /dev/snp device node, which can be opened by watch(8) multiple times. Even though snp(4) will be dead as of next week, it's nice having this in SVN, because: - We may want to MFC it to RELENG_7. - By the time we fix snp(4) again, it's already there, existing watch(8) binaries should already work. Just like bpf(4), I'm adding a symlink from snp0 to snp to remain binary compatible. 2008-08-15 13:07:07 +00:00			`.Pa /dev/snp`
			`is a snoop device which allows users to attach to any tty`
Clean up man page 1995-02-23 01:25:48 +00:00			`and watch activities on it.`
Talk about what the user needs to do to get the snp devices, and how watch(8) will try to help them by loading the module. PR: 25420 2001-11-24 17:02:58 +00:00			`The kernel must be compiled with`
			`.Cd "device snp" ,`
			`or the`
			`.Nm`
mdoc(7) police: laundry. 2002-08-13 14:12:31 +00:00			`module must be loaded,`
Talk about what the user needs to do to get the snp devices, and how watch(8) will try to help them by loading the module. PR: 25420 2001-11-24 17:02:58 +00:00			`for these devices to be available.`
Prepare for mdoc(7)NG. 2000-12-29 09:18:45 +00:00			`.Pp`
Clean up man page 1995-02-23 01:25:48 +00:00			`To associate a given`
mdoc(7) police: use the new features of the Nm macro. 2000-11-20 18:41:33 +00:00			`.Nm`
Correct a few grammar bogons. MFC after: 3 days 2002-07-31 09:32:22 +00:00			`device with a tty to be observed, open the`
mdoc(7) police: use the new features of the Nm macro. 2000-11-20 18:41:33 +00:00			`.Nm`
Restore the ability to detach from a tty via SIOCSTTY and document recent changes in a manpage. Reviewed by: cognet 2005-09-19 13:48:45 +00:00			`device and a tty device, and then issue the`
mdoc(7) police: laundry. 2002-08-13 14:12:31 +00:00			`.Dv SNPSTTY`
Restore the ability to detach from a tty via SIOCSTTY and document recent changes in a manpage. Reviewed by: cognet 2005-09-19 13:48:45 +00:00			`ioctl on`
			`.Nm`
			`device.`
mdoc(7) police: laundry. 2002-08-13 14:12:31 +00:00			`The argument passed to the`
			`.Xr ioctl 2`
			`is the address of a variable of type`
Restore the ability to detach from a tty via SIOCSTTY and document recent changes in a manpage. Reviewed by: cognet 2005-09-19 13:48:45 +00:00			`.Vt int ,`
			`holding the file descriptor of a tty device.`
mdoc(7) police: laundry. 2002-08-13 14:12:31 +00:00			`To detach the`
			`.Nm`
			`device from a tty use a pointer to a value of`
Restore the ability to detach from a tty via SIOCSTTY and document recent changes in a manpage. Reviewed by: cognet 2005-09-19 13:48:45 +00:00			`\-1.`
Clean up man page 1995-02-23 01:25:48 +00:00			`.Pp`
mdoc(7) police: laundry. 2002-08-13 14:12:31 +00:00			`The`
			`.Dv SNPGTTY`
			`ioctl returns information about the current tty attached to`
Clean up man page 1995-02-23 01:25:48 +00:00			`the open`
mdoc(7) police: use the new features of the Nm macro. 2000-11-20 18:41:33 +00:00			`.Nm`
Clean up man page 1995-02-23 01:25:48 +00:00			`device.`
			`.Pp`
mdoc(7) police: laundry. 2002-08-13 14:12:31 +00:00			`The`
			`.Dv FIONREAD`
			`ioctl returns a positive value equal to the number of characters`
Clean up man page 1995-02-23 01:25:48 +00:00			`in a read buffer.`
			`Special values defined are:`
mdoc(7) police: laundry. 2002-08-13 14:12:31 +00:00			`.Bl -tag -width ".Dv SNP_TTYCLOSE"`
Clean up man page 1995-02-23 01:25:48 +00:00			`.It Dv SNP_OFLOW`
Ispell sweep of share/man/man4. 2002-01-21 12:09:13 +00:00			`device overflow occurred, device detached.`
Clean up man page 1995-02-23 01:25:48 +00:00			`.It Dv SNP_TTYCLOSE`
			`tty not attached.`
			`.It Dv SNP_DETACH`
mdoc(7) police: use the new features of the Nm macro. 2000-11-20 18:41:33 +00:00			`.Nm`
Fix a bunch of spelling errors in a bunch of man pages. 1996-01-30 13:52:50 +00:00			`device has been detached by user or tty device has been closed`
			`and detached.`
Prepare for mdoc(7)NG. 2000-12-29 09:18:45 +00:00			`.El`
Move ipfirewall.4 & snp.4 facility manpage to share/man/man4 1995-02-17 18:48:36 +00:00			`.Sh SEE ALSO`
Clean up man page 1995-02-23 01:25:48 +00:00			`.Xr pty 4 ,`
Sort cross references. 1996-12-26 16:16:37 +00:00			`.Xr sio 4 ,`
Talk about what the user needs to do to get the snp devices, and how watch(8) will try to help them by loading the module. PR: 25420 2001-11-24 17:02:58 +00:00			`.Xr kldload 8 ,`
Sort cross references. 1996-12-26 16:16:37 +00:00			`.Xr watch 8`
Sort sections. 2005-01-21 08:36:40 +00:00			`.Sh HISTORY`
			`The`
			`.Nm`
			`device first appeared in`
			`.Fx 2.1 .`
Reintroduce the snp(4) driver. Because the TTY hooks interface was not finished when I imported the MPSAFE TTY layer, I had to disconnect the snp(4) driver. This snp(4) implementation has been sitting in my P4 branch for some time now. Unfortunately it still doesn't use the same error handling as snp(4) (returning codes through FIONREAD), but it should already be usable. I'm committing this to SVN, hoping someone else could polish off its rough edges. It's always better than having a broken driver sitting in the tree. 2008-11-05 15:04:03 +00:00			`In`
			`.Fx 8.0`
			`the`
			`.Nm`
			`driver was rewritten to work with the replaced TTY subsystem.`
Sort sections. 2005-01-21 08:36:40 +00:00			`.Sh AUTHORS`
Reintroduce the snp(4) driver. Because the TTY hooks interface was not finished when I imported the MPSAFE TTY layer, I had to disconnect the snp(4) driver. This snp(4) implementation has been sitting in my P4 branch for some time now. Unfortunately it still doesn't use the same error handling as snp(4) (returning codes through FIONREAD), but it should already be usable. I'm committing this to SVN, hoping someone else could polish off its rough edges. It's always better than having a broken driver sitting in the tree. 2008-11-05 15:04:03 +00:00			`The author of the current implementation is`
			`.An Ed Schouten Aq ed@FreeBSD.org .`
			`Previous versions of`
			`.Nm`
			`were based on code written by`
			`.An Ugen J.S. Antsilevich Aq ugen@NetVision.net.il .`
Move ipfirewall.4 & snp.4 facility manpage to share/man/man4 1995-02-17 18:48:36 +00:00			`.Sh BUGS`
Reintroduce the snp(4) driver. Because the TTY hooks interface was not finished when I imported the MPSAFE TTY layer, I had to disconnect the snp(4) driver. This snp(4) implementation has been sitting in my P4 branch for some time now. Unfortunately it still doesn't use the same error handling as snp(4) (returning codes through FIONREAD), but it should already be usable. I'm committing this to SVN, hoping someone else could polish off its rough edges. It's always better than having a broken driver sitting in the tree. 2008-11-05 15:04:03 +00:00			`This version of`
			`.Nm`
			`does not return proper error codes when calling`
			`.Dv FIONREAD .`
			`It also does not allow`
			`.Dv SNPSTTY`
			`to detach itself from the TTY.`