diff options
Diffstat (limited to 'share/man')
| -rw-r--r-- | share/man/man4/snp.4 | 113 |
1 files changed, 72 insertions, 41 deletions
diff --git a/share/man/man4/snp.4 b/share/man/man4/snp.4 index 47b97d8..f293070 100644 --- a/share/man/man4/snp.4 +++ b/share/man/man4/snp.4 @@ -1,49 +1,80 @@ -.Dd Februar 17, 1995 -.Dt SNP(4) -.Os +.\" +.\" @(#)snp.4 1.1 (FreeBSD) 2/17/95 +.\" +.Dd February 17, 1995 +.Dt SNP 4 +.Os FreeBSD .Sh NAME - - snp - tty snoop interface. - +.Nm snp +.Nd tty snoop interface .Sh SYNOPSIS -#include <sys/snoop.h> - +.Fd #include <sys/ioctl.h> +.Fd #include <sys/snoop.h> +.Ft int +.Fn ioctl fd SNPSTTY &snptty +.Ft int +.Fn ioctl fd SNPGTTY &snptty +.Ft int +.Fn ioctl fd FIONREAD 0 .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. +/dev/snp? are snoop devices which allow user to attach to any tty +and watch activities on it. -st_unit - number of tty unit. -By specifying ever st_type or st_unit -1 user can detach snp -device from tty. +To associate a given +.Nm snp +device with a tty to be observed, open the +.Nm snp +device and then use the SNPSTTY ioctl. +The argument passed to the IOCTL is the address of a structure of +the following type: +.Bd -literal -ffset indent +struct snptty { + int st_type; /* type of the tty to attach */ + int st_unit; /* number of the tty unit */ +} - 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. - +#define ST_PTY 0 /* regular pty */ +#define ST_VTY 1 /* syscons vty */ +#define ST_SIO 2 /* serial lines */ +.Ed +.Pp +By setting st_type or st_unit to -1, the user may detach the snp device +for a tty. +.Pp +The SNPGTTY ioctl returns information about the current tty attached to +the open +.Nm snp +device. +.Pp +The FIONREAD ioctl returns a positive value equal to the number of characters +in a read buffer. +Special values defined are: +.Bl -tag -width SNP_TTYCLOSE +.It Dv SNP_OFLOW +device overflow occured, device detatched. +.It Dv SNP_TTYCLOSE +tty not attached. +.It Dv SNP_DETACH +.Nm snp +device has been detatched by user or tty device has been closed +and detatched. .Sh SEE ALSO - -watch(8), pty(4), sio(4) +.Xr watch 8 , +.Xr pty 4 , +.Xr sio 4 +.Sh RESTRICTIONS +Only the superuser may access the +.Nm snp +devices. .Sh BUGS - -While in line mode,user input can't be seen. -Has no ability to write to attached tty device. - +While in line mode, user input can't be seen. +.Nm +snp +is a read-only device, there is no ability to write to attached tty device. +.Sh AUTHOR +Ugen J.S. Antsilevich <ugen@NetVision.net.il> .Sh HISTORY -FreeBSD 2.1 by Ugen J.S.Antsilevich <ugen@NetVision.net.il> +The +.Nm +snp +device first appeared in FreeBSD 2.1. |
