About capture the system calls of daemon process

[Nate Eldredge]

Wenjian Luo writes:
 > Dear all,
 > 	I want to capture the system calls of daemon process.
 > Now I meet two related questions:
 >   (1)for telnet or ftp server, and so on:
 > 	Because the ftp server (such as wu-ftp) or telnet sever (such as
 > /usr/sbin/in.telnetd) are activated by xinetd, how to capture
 > their system call sequences by strace?
 >      I try to capture xinetd, by it is too hard to separate the
 > the system calls of in.telnetd, wu-ftp, and others.

The -ff option may be helpful.  It dumps every process to a separate
file.  So you just have to find the one you want (which should be easy
from the exec at the top).

 >    (2)for lpd (print server) or httpd (http server), and so on:
 > there are executed by /usr/sbin/lpd or /usr/sbin/httpd,
 > how to capture it?
 >    It seem that "strace -f -o myoutfile /usr/sbin/lpd " does not
 > work properly.

What goes wrong?

If you don't care about what the daemon does on startup, you could
just start it normally and attach afterwards using -p.

-- 

Nate Eldredge
neldredge at hmc.edu