OT: setrlimit equivalent to prevent unlink or truncate

[Chris Turner]

Johannes Hofmann wrote:
Hi,

I'm wondering whether there is a way to prevent a process to modify 
the file system. setrlimit(RLIMIT_FSIZE) to 0 almost does the trick,
but unfortunately it does not prevent unlink() or truncate().
Is there any reason why there is no limit to prevent unlink or
truncate?

if it works, mounting the FS readonly should work..

also, chflags might be helpful..

or is this a coding question about coding the program that calls 
setrlimit() ?