ccastdf@prism.gatech.EDU (Dave) (11/08/90)
How do I (from C) get the information on what a user is doing. I have
seen the output from a w (who is online, and what they are doing), but
I can't figure out where it is coming from.
Thanks in advance.
David Frascone
--
David Frascone
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!ccastdf
Internet: ccastdf@prism.gatech.educpcahil@virtech.uucp (Conor P. Cahill) (11/08/90)
In article <16642@hydra.gatech.EDU> ccastdf@prism.gatech.EDU (Dave) writes: >How do I (from C) get the information on what a user is doing. I have >seen the output from a w (who is online, and what they are doing), but >I can't figure out where it is coming from. do a popen("ps"...) or a popen("w"...) -- Conor P. Cahill (703)430-9247 Virtual Technologies, Inc., uunet!virtech!cpcahil 46030 Manekin Plaza, Suite 160 Sterling, VA 22170
subbarao@phoenix.Princeton.EDU (Kartik Subbarao) (11/09/90)
In article <1990Nov08.131534.10938@virtech.uucp> cpcahil@virtech.UUCP (Conor P. Cahill) writes: >In article <16642@hydra.gatech.EDU> ccastdf@prism.gatech.EDU (Dave) writes: >>How do I (from C) get the information on what a user is doing. I have >>seen the output from a w (who is online, and what they are doing), but >>I can't figure out where it is coming from. > >do a popen("ps"...) or a popen("w"...) That's probably the simplest way to do things, but at least in the case of "w" we can be a bit more informative. w finds out who is on from reading /etc/utmp (the format of /etc/utmp and /etc/wtmp is described in utmp(5). In order to find out what processes are running, it either calls ps or is already setgid kmem so it can peek at /dev/kmem. Then it does something to find out the most "interesting" process for each user and displays it. So, to basically answer your question, if you want to find out solely who is on from a C program, you can use the utmp interface, but if you want processes, I guess a popen to ps might not be a bad idea. -Kartik (I need a new .signature -- any suggestions?) subbarao@{phoenix or gauguin}.Princeton.EDU -|Internet kartik@silvertone.Princeton.EDU (NeXT mail) -| SUBBARAO@PUCC.BITNET - Bitnet
brnstnd@kramden.acf.nyu.edu (Dan Bernstein) (11/09/90)
In article <3933@idunno.Princeton.EDU> subbarao@phoenix.Princeton.EDU (Kartik Subbarao) writes: [ w ] > In order to find out what processes are running, it either > calls ps or is already setgid kmem so it can peek at /dev/kmem. I haven't seen a version that calls ps. Note that /dev/kmem used to be readable on most systems (and still is on many), so system-status programs didn't have to be setuid or setgid. > Then it does something to find > out the most "interesting" process for each user and displays it. Usually w pretends that processes don't wrap around, and takes a System V view of the world. The former means that it takes the highest-numbered process as the latest process invoked on the terminal. The latter means that it checks first only for processes not ignoring interrupts, since that (usually) characterizes foreground processes under System V. Only if it doesn't find a foreground process does it look for background processes on the terminal. Under BSD, foreground processes are distinguished by their process groups, though this would require w to open the terminal and figure out the foreground process group. > (I need a new .signature -- any suggestions?) How 'bout ``It's your fault that I post articles with 100 columns''? ---Dan