kern_sysctl.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

static int
sysctl_sysctl_name(SYSCTL_HANDLER_ARGS)
{
	int *name = (int *) arg1;
	u_int namelen = arg2;
	int error = 0;
	struct sysctl_oid *oid;
	struct sysctl_oid_list *lsp = &sysctl__children, *lsp2;
	char buf[10];

	while (namelen) {
		if (!lsp) {
			snprintf(buf,sizeof(buf),"%d",*name);
			if (req->oldidx)
				error = SYSCTL_OUT(req, ".", 1);
			if (!error)
				error = SYSCTL_OUT(req, buf, strlen(buf));
			if (error)
				return (error);
			namelen--;
			name++;
			continue;
		}
		lsp2 = 0;
		SLIST_FOREACH(oid, lsp, oid_link) {
			if (oid->oid_number != *name)
				continue;

			if (req->oldidx)
				error = SYSCTL_OUT(req, ".", 1);
			if (!error)
				error = SYSCTL_OUT(req, oid->oid_name,
					strlen(oid->oid_name));
			if (error)
				return (error);

			namelen--;
			name++;

			if ((oid->oid_kind & CTLTYPE) != CTLTYPE_NODE) 
				break;

			if (oid->oid_handler)
				break;

			lsp2 = (struct sysctl_oid_list *)oid->oid_arg1;
			break;
		}
		lsp = lsp2;
	}
	return (SYSCTL_OUT(req, "", 1));
}

SYSCTL_NODE(_sysctl, 1, name, CTLFLAG_RD, sysctl_sysctl_name, "");

static int
sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen, 
	int *next, int *len, int level, struct sysctl_oid **oidpp)
{
	struct sysctl_oid *oidp;

	*len = level;
	SLIST_FOREACH(oidp, lsp, oid_link) {
		*next = oidp->oid_number;
		*oidpp = oidp;

		if (oidp->oid_kind & CTLFLAG_SKIP)
			continue;

		if (!namelen) {
			if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) 
				return 0;
			if (oidp->oid_handler) 
				/* We really should call the handler here...*/
				return 0;
			lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
			if (!sysctl_sysctl_next_ls(lsp, 0, 0, next+1, 
				len, level+1, oidpp))
				return 0;
			goto next;
		}

		if (oidp->oid_number < *name)
			continue;

		if (oidp->oid_number > *name) {
			if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
				return 0;
			if (oidp->oid_handler)
				return 0;
			lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
			if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1, 
				next+1, len, level+1, oidpp))
				return (0);
			goto next;
		}
		if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
			continue;

		if (oidp->oid_handler)
			continue;

		lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
		if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1, next+1, 
			len, level+1, oidpp))
			return (0);
	next:
		namelen = 1;
		*len = level;
	}
	return 1;
}

static int
sysctl_sysctl_next(SYSCTL_HANDLER_ARGS)
{
	int *name = (int *) arg1;
	u_int namelen = arg2;
	int i, j, error;
	struct sysctl_oid *oid;
	struct sysctl_oid_list *lsp = &sysctl__children;
	int newoid[CTL_MAXNAME];

	i = sysctl_sysctl_next_ls(lsp, name, namelen, newoid, &j, 1, &oid);
	if (i)
		return ENOENT;
	error = SYSCTL_OUT(req, newoid, j * sizeof (int));
	return (error);
}

SYSCTL_NODE(_sysctl, 2, next, CTLFLAG_RD, sysctl_sysctl_next, "");

static int
name2oid (char *name, int *oid, int *len, struct sysctl_oid **oidpp)
{
	int i;
	struct sysctl_oid *oidp;
	struct sysctl_oid_list *lsp = &sysctl__children;
	char *p;

	if (!*name)
		return ENOENT;

	p = name + strlen(name) - 1 ;
	if (*p == '.')
		*p = '\0';

	*len = 0;

	for (p = name; *p && *p != '.'; p++) 
		;
	i = *p;
	if (i == '.')
		*p = '\0';

	oidp = SLIST_FIRST(lsp);

	while (oidp && *len < CTL_MAXNAME) {
		if (strcmp(name, oidp->oid_name)) {
			oidp = SLIST_NEXT(oidp, oid_link);
			continue;
		}
		*oid++ = oidp->oid_number;
		(*len)++;

		if (!i) {
			if (oidpp)
				*oidpp = oidp;
			return (0);
		}

		if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
			break;

		if (oidp->oid_handler)
			break;

		lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
		oidp = SLIST_FIRST(lsp);
		name = p+1;
		for (p = name; *p && *p != '.'; p++) 
				;
		i = *p;
		if (i == '.')
			*p = '\0';
	}
	return ENOENT;
}

static int
sysctl_sysctl_name2oid(SYSCTL_HANDLER_ARGS)
{
	char *p;
	int error, oid[CTL_MAXNAME], len;
	struct sysctl_oid *op = 0;

	if (!req->newlen) 
		return ENOENT;
	if (req->newlen >= MAXPATHLEN)	/* XXX arbitrary, undocumented */
		return (ENAMETOOLONG);

	p = malloc(req->newlen+1, M_SYSCTL, M_WAITOK);

	error = SYSCTL_IN(req, p, req->newlen);
	if (error) {
		free(p, M_SYSCTL);
		return (error);
	}

	p [req->newlen] = '\0';

	error = name2oid(p, oid, &len, &op);

	free(p, M_SYSCTL);

	if (error)
		return (error);

	error = SYSCTL_OUT(req, oid, len * sizeof *oid);
	return (error);
}

SYSCTL_PROC(_sysctl, 3, name2oid, CTLFLAG_RW|CTLFLAG_ANYBODY, 0, 0, 
	sysctl_sysctl_name2oid, "I", "");

static int
sysctl_sysctl_oidfmt(SYSCTL_HANDLER_ARGS)
{
	struct sysctl_oid *oid;
	int error;

	error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
	if (error)
		return (error);

	if (!oid->oid_fmt)
		return (ENOENT);
	error = SYSCTL_OUT(req, &oid->oid_kind, sizeof(oid->oid_kind));
	if (error)
		return (error);
	error = SYSCTL_OUT(req, oid->oid_fmt, strlen(oid->oid_fmt) + 1);
	return (error);
}


SYSCTL_NODE(_sysctl, 4, oidfmt, CTLFLAG_RD, sysctl_sysctl_oidfmt, "");

static int
sysctl_sysctl_oiddescr(SYSCTL_HANDLER_ARGS)
{
	struct sysctl_oid *oid;
	int error;

	error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
	if (error)
		return (error);

	if (!oid->descr)
		return (ENOENT);
	error = SYSCTL_OUT(req, oid->descr, strlen(oid->descr) + 1);
	return (error);
}

SYSCTL_NODE(_sysctl, 5, oiddescr, CTLFLAG_RD, sysctl_sysctl_oiddescr, "");

/*
 * Default "handler" functions.
 */

/*
 * Handle an int, signed or unsigned.
 * Two cases:
 *     a variable:  point arg1 at it.
 *     a constant:  pass it in arg2.
 */

int
sysctl_handle_int(SYSCTL_HANDLER_ARGS)
{
	int tmpout, error = 0;

	/*
	 * Attempt to get a coherent snapshot by making a copy of the data.
	 */
	if (arg1)
		tmpout = *(int *)arg1;
	else
		tmpout = arg2;
	error = SYSCTL_OUT(req, &tmpout, sizeof(int));

	if (error || !req->newptr)
		return (error);

	if (!arg1)
		error = EPERM;
	else
		error = SYSCTL_IN(req, arg1, sizeof(int));
	return (error);
}

/*
 * Handle a long, signed or unsigned.  arg1 points to it.
 */

int
sysctl_handle_long(SYSCTL_HANDLER_ARGS)
{
	int error = 0;
	long tmpout;

	/*
	 * Attempt to get a coherent snapshot by making a copy of the data.
	 */
	if (!arg1)
		return (EINVAL);
	tmpout = *(long *)arg1;
	error = SYSCTL_OUT(req, &tmpout, sizeof(long));

	if (error || !req->newptr)
		return (error);

	error = SYSCTL_IN(req, arg1, sizeof(long));
	return (error);
}

/*
 * Handle our generic '\0' terminated 'C' string.
 * Two cases:
 * 	a variable string:  point arg1 at it, arg2 is max length.
 * 	a constant string:  point arg1 at it, arg2 is zero.
 */

int
sysctl_handle_string(SYSCTL_HANDLER_ARGS)
{
	int error=0;
	char *tmparg;
	size_t outlen;

	/*
	 * Attempt to get a coherent snapshot by copying to a
	 * temporary kernel buffer.
	 */
retry:
	outlen = strlen((char *)arg1)+1;
	tmparg = malloc(outlen, M_SYSCTLTMP, M_WAITOK);

	if (strlcpy(tmparg, (char *)arg1, outlen) >= outlen) {
		free(tmparg, M_SYSCTLTMP);
		goto retry;
	}

	error = SYSCTL_OUT(req, tmparg, outlen);
	free(tmparg, M_SYSCTLTMP);

	if (error || !req->newptr)
		return (error);

	if ((req->newlen - req->newidx) >= arg2) {
		error = EINVAL;
	} else {
		arg2 = (req->newlen - req->newidx);
		error = SYSCTL_IN(req, arg1, arg2);
		((char *)arg1)[arg2] = '\0';
	}

	return (error);
}

/*
 * Handle any kind of opaque data.
 * arg1 points to it, arg2 is the size.
 */

int
sysctl_handle_opaque(SYSCTL_HANDLER_ARGS)
{
	int error;
	void *tmparg;

	/*
	 * Attempt to get a coherent snapshot, either by wiring the
	 * user space buffer or copying to a temporary kernel buffer
	 * depending on the size of the data.
	 */
	if (arg2 > PAGE_SIZE) {
		sysctl_wire_old_buffer(req, arg2);
		error = SYSCTL_OUT(req, arg1, arg2);
	} else {
		tmparg = malloc(arg2, M_SYSCTLTMP, M_WAITOK);
		bcopy(arg1, tmparg, arg2);
		error = SYSCTL_OUT(req, tmparg, arg2);
		free(tmparg, M_SYSCTLTMP);
	}

	if (error || !req->newptr)
		return (error);

	error = SYSCTL_IN(req, arg1, arg2);

	return (error);
}

/*
 * Transfer functions to/from kernel space.
 * XXX: rather untested at this point
 */
static int
sysctl_old_kernel(struct sysctl_req *req, const void *p, size_t l)
{
	size_t i = 0;

	if (req->oldptr) {
		i = l;
		if (req->oldlen <= req->oldidx)
			i = 0;
		else
			if (i > req->oldlen - req->oldidx)
				i = req->oldlen - req->oldidx;
		if (i > 0)
			bcopy(p, (char *)req->oldptr + req->oldidx, i);
	}
	req->oldidx += l;
	if (req->oldptr && i != l)
		return (ENOMEM);
	return (0);
}

static int
sysctl_new_kernel(struct sysctl_req *req, void *p, size_t l)
{
	if (!req->newptr)
		return 0;
	if (req->newlen - req->newidx < l)
		return (EINVAL);
	bcopy((char *)req->newptr + req->newidx, p, l);
	req->newidx += l;
	return (0);
}

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 error = 0;
	struct sysctl_req req;

	bzero(&req, sizeof req);

	req.td = td;

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

	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 = 1;

	SYSCTL_LOCK();

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

	if (req.lock == 2)
#ifdef __rtems__
    printf ("kern_sysctl: vsunlock needs to be called!\n");
#else
		vsunlock(req.oldptr, req.oldlen);
#endif
    
	SYSCTL_UNLOCK();

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

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

int
kernel_sysctlbyname(struct thread *td, char *name, void *old, size_t *oldlenp,
    void *new, size_t newlen, size_t *retval)
{
        int oid[CTL_MAXNAME];
        size_t oidlen, plen;
	int error;

	oid[0] = 0;		/* sysctl internal magic */
	oid[1] = 3;		/* name2oid */
	oidlen = sizeof(oid);

	error = kernel_sysctl(td, oid, 2, oid, &oidlen,
	    (void *)name, strlen(name), &plen);
	if (error)
		return (error);

	error = kernel_sysctl(td, oid, plen / sizeof(int), old, oldlenp,
	    new, newlen, retval);
	return (error);
}