How to trace a raw (character) device stream on Unix ?

Posted by Fabien on Stack Overflow See other posts from Stack Overflow or by Fabien
Published on 2010-05-03T03:05:47Z Indexed on 2010/05/03 3:18 UTC
Read the original article Hit count: 341

Filed under:

unix

|

daemon

I'm trying to trace what is transiting in a raw (character) device on an Unix system (ex: /dev/tty.baseband) for DEBUG purpose.

I am thinking of creating a deamon that would:

upon start rename /dev/tty.baseband to /dev/tty.baseband.old.
create a raw node /dev/tty.baseband
spawn two threads:
Thread 1: reading /dev/tty.baseband.old writing into /dev/tty.baseband
Thread 2: reading /dev/tty.baseband writing into /dev/tty.baseband.old

This would work a little bit like a MITM process. I wonder if there is not a 'standard' way to do this.

© Stack Overflow or respective owner

Related posts about unix

polkit: disable all users except those in group wheel?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
Is it possible to do the following using 1 polkit .pkla file? Disable all users except those in the wheel group from using polkit. The users in the wheel group will need to provide the root password when using polkit. /etc/polkit-1/localauthority/50-local.d/wheel-only.pkla [disable all users… >>> More
How to find other end of unix socket connection?

as seen on Server Fault - Search for 'Server Fault'
I have a process (dbus-daemon) which has many open connection over UNIX sockets. One of these connections is fd #36: =$ ps uw -p 23284 USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND depesz 23284 0.0 0.0 24680 1772 ? Ss 15:25 0:00 /bin/dbus-daemon --fork… >>> More
Meaning of directories on Unix and Unix like systems

as seen on Server Fault - Search for 'Server Fault'
I've been using Linux for a couple of years now but I still haven't figured out what the origin or meaning of some the directory names are on Unix and Unix like systems. E.g. what does etc stand for or var? Where does the opt name come from? And while we're on the topic anyway. Can someone give a… >>> More
Easy understanding of UNIX and UNIX shell scripting!!

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi All, I am beginner to UNIX,UNIX Shell Scripting. Can you please guide me through any excellent sites for unix(which are easy to understand),some study materials(tutorials),video tutorials. Please help!! Thanks! >>> More
Is Mac OS X a licensed Unix or Unix-like clone that conforms to Unix specification?

as seen on Super User - Search for 'Super User'
Is Mac OS X developed on a licensed Unix or is it a Unix-like clone that, unlike Linux, conforms to Unix specification well enough to be registered as a Unix OS. Not until Leopard, Mac OS X did not gain the Unix certification. But in Leopard, Terminal still print: GNU bash, version 3.2.48(1)-release… >>> More

Related posts about daemon

Unable to configure a service to run at startup with update-rc.d

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I would like to have transmission-daemon and vnstat automatically run at startup. I was able to configure this for apache2 and proftpd with exactly the same commands. 795 sudo update-rc.d transmission-daemon remove 797 sudo update-rc.d -f transmission-daemon remove 798 sudo update-rc.d transmission-daemon… >>> More
Launching a PHP daemon from an LSB init script w/ start-stop-daemon

as seen on Server Fault - Search for 'Server Fault'
I'm writing an lsb init script (admittedly something I've never done from scratch) that launches a php script that daemonizes itself. The php script starts off like so: #!/usr/bin/env php <?php /* do some stuff */ It's then started like so in the init script: # first line is args to start-stop-daemon… >>> More
External Monitors shut off when Laptop Lid closes

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have researched the solution... gconftool-2 --type string --set /apps/gnome-power-manager/buttons/lid_ac "nothing" does not fix it. I have two external monitors and when I close my lid the settings are reset and the laptop's monitor is set to the default. Thanks! gsettings list-recursively… >>> More
How to prevent screen locking when lid is closed?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have Ubuntu 11.10 with Gnome 3 (no Unity), gnome-screen-saver has been removed and replaced with xscreensaver. The screensaver stuff all works fine -- no complaints there. When I close my laptop lid, even for a second, the screen locks (and the dialog box asking for my password is xscreensaver's)… >>> More
WD MBWE II (White Strip Light) 2TB - unable to access data

as seen on Super User - Search for 'Super User'
I have a WD MBWE II (White Strip Light) 2TB - (WD20000H2NC-00) Was working fine until a few days ago. I guess there was a power failure and after that I am unable to access the 'Public' or the 'Download' folder anymore. I have been searching for answers everywhere but came up empty handed. Web… >>> More