freebsd-skq/sys/kern/kern_vimage.c
zec 71a3c7baca Extend the vnet module registration / initialization framework
first introduced @ r190909 with a vnet module deregistration
service.

kldunloadable modules, which are currently using vnet_mod_register()
to attach their per-vnet initialization routines to the vnet
initialization framework, should call vnet_mod_deregister() before
acknowledging MOD_UNLOAD requests in their mod_event handlers.  Such
changes to the existing code base will follow in subsequent commits.

vnet_mod_deregister() does not check whether departing vnet modules
are registered as prerequisites for another module(s), so it should
be used with care.  Currently I'm only aware of vnet modules which
are leafs on module dependency graphs that are kldunloadable.

This change also introduces per-vnet module destructor handler, which
calls vnet's module cleanup function, which (if required) has to be
registered in vnet module's vnet_modinfo_t structure .vmi_idetach
field.  Once options VIMAGE becomes operational, the framework will
take care that module's cleanup function become invoked for each
active vnet instance, and that the memory allocated for each instance
gets freed.  Currently calls to destructor handlers must always
succeed.
2009-04-26 07:09:39 +00:00

304 lines
8.4 KiB
C

/*-
* Copyright (c) 2004-2008 University of Zagreb
* Copyright (c) 2006-2008 FreeBSD Foundation
*
* This software was developed by the University of Zagreb and the
* FreeBSD Foundation under sponsorship by the Stichting NLnet and the
* FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/types.h>
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/vimage.h>
#ifndef VIMAGE_GLOBALS
MALLOC_DEFINE(M_VIMAGE, "vimage", "vimage resource container");
static TAILQ_HEAD(vnet_modlink_head, vnet_modlink) vnet_modlink_head;
static TAILQ_HEAD(vnet_modpending_head, vnet_modlink) vnet_modpending_head;
static void vnet_mod_complete_registration(struct vnet_modlink *);
static int vnet_mod_constructor(struct vnet_modlink *);
static int vnet_mod_destructor(struct vnet_modlink *);
void
vnet_mod_register(const struct vnet_modinfo *vmi)
{
vnet_mod_register_multi(vmi, NULL, NULL);
}
void
vnet_mod_register_multi(const struct vnet_modinfo *vmi, void *iarg,
char *iname)
{
struct vnet_modlink *vml, *vml_iter;
/* Do not register the same {module, iarg} pair more than once. */
TAILQ_FOREACH(vml_iter, &vnet_modlink_head, vml_mod_le)
if (vml_iter->vml_modinfo == vmi && vml_iter->vml_iarg == iarg)
break;
if (vml_iter != NULL)
panic("registering an already registered vnet module: %s",
vml_iter->vml_modinfo->vmi_name);
vml = malloc(sizeof(struct vnet_modlink), M_VIMAGE, M_NOWAIT);
/*
* XXX we support only statically assigned module IDs at the time.
* In principle modules should be able to get a dynamically
* assigned ID at registration time.
*
* If a module is registered in multiple instances, then each
* instance must have both iarg and iname set.
*/
if (vmi->vmi_id >= VNET_MOD_MAX)
panic("invalid vnet module ID: %d", vmi->vmi_id);
if (vmi->vmi_name == NULL)
panic("vnet module with no name: %d", vmi->vmi_id);
if ((iarg == NULL) ^ (iname == NULL))
panic("invalid vnet module instance: %s", vmi->vmi_name);
vml->vml_modinfo = vmi;
vml->vml_iarg = iarg;
vml->vml_iname = iname;
/* Check whether the module we depend on is already registered. */
if (vmi->vmi_dependson != vmi->vmi_id) {
TAILQ_FOREACH(vml_iter, &vnet_modlink_head, vml_mod_le)
if (vml_iter->vml_modinfo->vmi_id ==
vmi->vmi_dependson)
break; /* Depencency found, we are done. */
if (vml_iter == NULL) {
#ifdef DEBUG_ORDERING
printf("dependency %d missing for vnet mod %s,"
"postponing registration\n",
vmi->vmi_dependson, vmi->vmi_name);
#endif /* DEBUG_ORDERING */
TAILQ_INSERT_TAIL(&vnet_modpending_head, vml,
vml_mod_le);
return;
}
}
vnet_mod_complete_registration(vml);
}
void
vnet_mod_complete_registration(struct vnet_modlink *vml)
{
VNET_ITERATOR_DECL(vnet_iter);
struct vnet_modlink *vml_iter;
TAILQ_INSERT_TAIL(&vnet_modlink_head, vml, vml_mod_le);
VNET_FOREACH(vnet_iter) {
CURVNET_SET_QUIET(vnet_iter);
vnet_mod_constructor(vml);
CURVNET_RESTORE();
}
/* Check for pending modules depending on us. */
do {
TAILQ_FOREACH(vml_iter, &vnet_modpending_head, vml_mod_le)
if (vml_iter->vml_modinfo->vmi_dependson ==
vml->vml_modinfo->vmi_id)
break;
if (vml_iter != NULL) {
#ifdef DEBUG_ORDERING
printf("vnet mod %s now registering,"
"dependency %d loaded\n",
vml_iter->vml_modinfo->vmi_name,
vml->vml_modinfo->vmi_id);
#endif /* DEBUG_ORDERING */
TAILQ_REMOVE(&vnet_modpending_head, vml_iter,
vml_mod_le);
vnet_mod_complete_registration(vml_iter);
}
} while (vml_iter != NULL);
}
void
vnet_mod_deregister(const struct vnet_modinfo *vmi)
{
vnet_mod_deregister_multi(vmi, NULL, NULL);
}
void
vnet_mod_deregister_multi(const struct vnet_modinfo *vmi, void *iarg,
char *iname)
{
VNET_ITERATOR_DECL(vnet_iter);
struct vnet_modlink *vml;
TAILQ_FOREACH(vml, &vnet_modlink_head, vml_mod_le)
if (vml->vml_modinfo == vmi && vml->vml_iarg == iarg)
break;
if (vml == NULL)
panic("cannot deregister unregistered vnet module %s",
vmi->vmi_name);
VNET_FOREACH(vnet_iter) {
CURVNET_SET_QUIET(vnet_iter);
vnet_mod_destructor(vml);
CURVNET_RESTORE();
}
TAILQ_REMOVE(&vnet_modlink_head, vml, vml_mod_le);
free(vml, M_VIMAGE);
}
static int vnet_mod_constructor(struct vnet_modlink *vml)
{
const struct vnet_modinfo *vmi = vml->vml_modinfo;
#ifdef DEBUG_ORDERING
printf("instantiating vnet_%s", vmi->vmi_name);
if (vml->vml_iarg)
printf("/%s", vml->vml_iname);
printf(": ");
#ifdef VIMAGE
if (vmi->vmi_size)
printf("malloc(%zu); ", vmi->vmi_size);
#endif
if (vmi->vmi_iattach != NULL)
printf("iattach()");
printf("\n");
#endif
#ifdef VIMAGE
if (vmi->vmi_size) {
void *mem = malloc(vmi->vmi_size, M_VNET,
M_NOWAIT | M_ZERO);
if (mem == NULL) /* XXX should return error, not panic. */
panic("vi_alloc: malloc for %s\n", vmi->vmi_name);
curvnet->mod_data[vmi->vmi_id] = mem;
}
#endif
if (vmi->vmi_iattach != NULL)
vmi->vmi_iattach(vml->vml_iarg);
return (0);
}
static int
vnet_mod_destructor(struct vnet_modlink *vml)
{
const struct vnet_modinfo *vmi = vml->vml_modinfo;
#ifdef DEBUG_ORDERING
printf("destroying vnet_%s", vmi->vmi_name);
if (vml->vml_iarg)
printf("/%s", vml->vml_iname);
printf(": ");
if (vmi->vmi_idetach != NULL)
printf("idetach(); ");
#ifdef VIMAGE
if (vmi->vmi_size)
printf("free()");
#endif
printf("\n");
#endif
if (vmi->vmi_idetach)
vmi->vmi_idetach(vml->vml_iarg);
#ifdef VIMAGE
if (vmi->vmi_size) {
if (curvnet->mod_data[vmi->vmi_id] == NULL)
panic("vi_destroy: %s\n", vmi->vmi_name);
free(curvnet->mod_data[vmi->vmi_id], M_VNET);
curvnet->mod_data[vmi->vmi_id] = NULL;
}
#endif
return (0);
}
/*
* vi_symlookup() attempts to resolve name to address queries for
* variables which have been moved from global namespace to virtualization
* container structures, but are still directly accessed from legacy
* userspace processes via kldsym(2) and kmem(4) interfaces.
*/
int
vi_symlookup(struct kld_sym_lookup *lookup, char *symstr)
{
struct vnet_modlink *vml;
struct vnet_symmap *mapentry;
TAILQ_FOREACH(vml, &vnet_modlink_head, vml_mod_le) {
if (vml->vml_modinfo->vmi_symmap == NULL)
continue;
for (mapentry = vml->vml_modinfo->vmi_symmap;
mapentry->name != NULL; mapentry++) {
if (strcmp(symstr, mapentry->name) == 0) {
lookup->symvalue = (u_long) mapentry->base;
lookup->symsize = mapentry->size;
return (0);
}
}
}
return (ENOENT);
}
static void
vi_init(void *unused)
{
TAILQ_INIT(&vnet_modlink_head);
TAILQ_INIT(&vnet_modpending_head);
}
static void
vi_init_done(void *unused)
{
struct vnet_modlink *vml_iter;
if (TAILQ_EMPTY(&vnet_modpending_head))
return;
printf("vnet modules with unresolved dependencies:\n");
TAILQ_FOREACH(vml_iter, &vnet_modpending_head, vml_mod_le)
printf(" %d:%s depending on %d\n",
vml_iter->vml_modinfo->vmi_id,
vml_iter->vml_modinfo->vmi_name,
vml_iter->vml_modinfo->vmi_dependson);
panic("going nowhere without my vnet modules!");
}
SYSINIT(vimage, SI_SUB_VIMAGE, SI_ORDER_FIRST, vi_init, NULL);
SYSINIT(vimage_done, SI_SUB_VIMAGE_DONE, SI_ORDER_FIRST, vi_init_done, NULL);
#endif /* !VIMAGE_GLOBALS */