is it possible to programatically change an executable name (ucmd) of a unix process?

Question

Is it possible to programatically change an executable name (ucmd) of a unix process as reported by ps?

unix/POSIX way would be nice but Linux specific solution would suffice.

I want to change what is reported here

> ps -o ucmd    
CMD
zsh
ps

not this, this I know ;)

> ps -o command
COMMAND
zsh
ps -o command

thanks

P.S. Not trying to create a rootkit, its just that net-snmp looks at this name when checking processes and my program has a different name when called from init and directly from /etc/init.d (etc/rcX.d/SNNname instead of just name).

Answer 1

You can do this with the PR_SET_NAME function of prctl():

prctl(PR_SET_NAME, (unsigned long)"xyzzy", 0, 0, 0);

However, /etc/rcX.d/SNNname should be a (symlink to a) script that starts your process, not a link to the process executable itself. This would also solve the problem.