Re: new syscall tapset checked in, but needs work

[fche at redhat dot com (Frank Ch. Eigler)]

hunt wrote:

> [...]
>   rc = _stp_copy_from_user (THIS->__retvalue,
>                                     [...] THIS->addr,
>                                     num);

If, as appears from the runtime sources, this particular function is
not atomic, then it should not be called from an atomic probe handler.


Here is a more compact version of your final probe:

probe strace.* {
  if (pid() != target()) next
  if (returnp) {
     if (argstr != "") printf("%s(%s) = %d\n", name, argstr, returnval())
     else printf("%d\n", returnval())
  } else if (argstr != "")
     printf("%s(%s) = ", name, argstr)
}


> [...]Output looks like this:
> 
> > stap -c ps -g strace.stp
> open("/etc/ld.so.cache", O_RDONLY) = 4
> open("/lib/libtermcap.so.2", O_RDONLY) = 4
> read(4, [.ELF....................`K#.4.], 30) = 512
> [...]

Neato.


- FChE