El 18/12/2011 22:12, "Julian Elischer" <[email protected]> escribió: > > On 12/18/11 12:18 PM, Fernando Apesteguía wrote: >> >> Hi all, >> >> I'm writing a small module just for fun. I would like to have two variables: >> >> - "pid" of type unsigned int and RW so the user can set a pid >> - "process_name" as a string RD that will display the process name >> associated to that pid (or a message if the pid doesn't exist anymore) > > > this is dangerous as there are some places in the kernel where processes > are referenced by pid, so changing it may break kernel assumptions.
Sorry, i think i didn't explain it clearly. The "pid" variable is static in my module and it is used just to tell the module which information it should show in the other variable. >> >> My problem is with the handler functions. For "process_name", as it is >> read only, I wrote a simple handler that works fine. However, I want >> to write another one for "pid" so I can sanitize the input (avoiding >> pids< 0 and so). As I understand, the handler I specify with >> SYSCTL_OID will be called for both reads and writes. But, how can I >> tell what kind of operation is it, so I know if I have to use >> SYSCTL_OUT or SYSCTL_IN? I tried to have a look at sysctl_handle_int >> but I don't fully understand what is going on with the arg1 parameter. >> What is it for? >> >> Thanks in advance. >> _______________________________________________ >> [email protected] mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers >> To unsubscribe, send any mail to "[email protected] " >> > _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[email protected]"
