50 lines
1.5 KiB
Groff
50 lines
1.5 KiB
Groff
.Dd Februar 17, 1995
|
|
.Dt SNP(4)
|
|
.Os
|
|
.Sh NAME
|
|
|
|
snp - tty snoop interface.
|
|
|
|
.Sh SYNOPSIS
|
|
#include <sys/snoop.h>
|
|
|
|
.Sh DESCRIPTION
|
|
/dev/snp? are snoop devices which allow user to attach to any tty
|
|
and watch activities on it. Device can be used by root only.
|
|
To connect device to tty use special iocontrol SNPSTTY.Argument to
|
|
it is a structure 'snptty'.
|
|
struct snptty {
|
|
int st_type;
|
|
int st_unit;
|
|
}
|
|
|
|
st_type - type of tty to attach. Currently supported are :
|
|
ST_PTY - pseudo-tty devices.
|
|
ST_VTY - virtual ttys (syscons).
|
|
ST_SIO - serial ttys.
|
|
|
|
st_unit - number of tty unit.
|
|
By specifying ever st_type or st_unit -1 user can detach snp
|
|
device from tty.
|
|
|
|
SNPGTTY - iocontrol returns current tty attached.
|
|
FIONREAD - iocontrol returns ever positive value equal to number of
|
|
characters in read buffer. Also special values defined:
|
|
SNP_OFLOW - device overflow occured,device automatically
|
|
detached.
|
|
SNP_TTYCLOSE - tty still has not been attached.
|
|
SNP_DETACH - snp device has been detached by user or
|
|
tty device has been closed and detached
|
|
automatically.
|
|
|
|
.Sh SEE ALSO
|
|
|
|
watch(8), pty(4), sio(4)
|
|
.Sh BUGS
|
|
|
|
While in line mode,user input can't be seen.
|
|
Has no ability to write to attached tty device.
|
|
|
|
.Sh HISTORY
|
|
FreeBSD 2.1 by Ugen J.S.Antsilevich <ugen@NetVision.net.il>
|