Date: Tue, 18 Dec 2018 14:13:50 -0500 From: Ryan Stone <rysto32@gmail.com> To: Austin Shafer <amshafer64@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: ENOMEM when calling sysctl_handle_int from custom handler Message-ID: <CAFMmRNwyd6meO2LOfHLk8pg3y9x=RaE7hukw8cJAa0s%2BvgZTxg@mail.gmail.com> In-Reply-To: <861s6fpyua.fsf@triplebuff.com> References: <861s6fpyua.fsf@triplebuff.com>
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You should not pass arg1 and arg2 to sysctl_handle_int(). You instead
need to pass a pointer to a local value containing the value you want
to return to the sysctl caller. After sysctl_handle_int returns, if
it returned 0 and req->newptr is non-NULL, then the integer value will
contain the new value that was passed to you from userland. You want
something that looks like this:
int
my_sysctl_handler(SYSCTL_HANDLER_ARGS)
{
int val, error;
val = 5; /* Or whatever value you want to return from userland. */
error = sysctl_handle_int(oidp, &val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
/* val contains the value set by the caller, so do something
interesting with it here. */
return (0);
}
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