Function kernel_sysctl

freebsd/kern/kern_sysctl.c:1952–1997

}

int
kernel_sysctl(struct thread *td, int *name, u_int namelen, void *old,
    size_t *oldlenp, void *new, size_t newlen, size_t *retval, int flags)
{
	int error = 0;
	struct sysctl_req req;

	bzero(&req, sizeof req);

	req.td = td;
	req.flags = flags;

	if (oldlenp) {
		req.oldlen = *oldlenp;
	}
	req.validlen = req.oldlen;

	if (old) {
		req.oldptr= old;
	}

	if (new != NULL) {
		req.newlen = newlen;
		req.newptr = new;
	}

	req.oldfunc = sysctl_old_kernel;
	req.newfunc = sysctl_new_kernel;
	req.lock = REQ_UNWIRED;

	error = sysctl_root(0, name, namelen, &req);

	if (req.lock == REQ_WIRED && req.validlen > 0)
		vsunlock(req.oldptr, req.validlen);

	if (error && error != ENOMEM)
		return (error);

	if (retval) {
		if (req.oldptr && req.oldidx > req.validlen)
			*retval = req.validlen;
		else
			*retval = req.oldidx;
	}
	return (error);
}

int
kernel_sysctlbyname(struct thread *td, char *name, void *old, size_t *oldlenp,