dtrace discuss - Nov 2007 - read: which file name

an active process that opens and closes files all the time reuses file
descriptors. Therefor a certain fd value might not correspond with that same fd
value (in that same process) a couple of seconds later.

What structure is available in a DTrace program from within a read,write,lseek
and other fd using system call related probes that can be used to drill down to
the file name?
What do these do when the desciptor is not a file but say a socket?

Thanks
Paul


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Hey Paul:

You can use the fds inlined translator to get to the file name.

For example to see all the files that are being read(2) in the system

dtrace -n syscall::read:entry''{trace(fds[arg0].fi_pathname)}''

Let me know if you need more details

-Angelo


On Nov 29, 2007, at 12:32 PM, Paul van den Bogaard wrote:
> an active process that opens and closes files all the time reuses  
> file descriptors. Therefor a certain fd value might not correspond  
> with that same fd value (in that same process) a couple of seconds  
> later.
>
> What structure is available in a DTrace program from within a  
> read,write,lseek and other fd using system call related probes that  
> can be used to drill down to the file name?
> What do these do when the desciptor is not a file but say a socket?
>
> Thanks
> Paul
>
>
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> This message posted from opensolaris.org
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org

fds[ fd ].fi_pathname is the magical thing it seems. 

Thanks Angelo!

For example:

syscall::read:entry 
{
    printf("s\n", fds[arg0].fi_pathname);
}


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