hook functions into hhook points which register after the modules were loaded - potentially useful during boot or if hhook points are dynamically registered. MFC after: 1 week
379 lines
9.3 KiB
C
379 lines
9.3 KiB
C
/*-
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* Copyright (c) 2010,2013 Lawrence Stewart <lstewart@freebsd.org>
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* Copyright (c) 2010 The FreeBSD Foundation
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* All rights reserved.
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*
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* This software was developed by Lawrence Stewart while studying at the Centre
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* for Advanced Internet Architectures, Swinburne University of Technology,
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* made possible in part by grants from the FreeBSD Foundation and Cisco
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* University Research Program Fund at Community Foundation Silicon Valley.
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*
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* Portions of this software were developed at the Centre for Advanced
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* Internet Architectures, Swinburne University of Technology, Melbourne,
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* Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/hhook.h>
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#include <sys/khelp.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/module_khelp.h>
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#include <sys/osd.h>
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#include <sys/queue.h>
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#include <sys/refcount.h>
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#include <sys/rwlock.h>
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#include <sys/systm.h>
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static struct rwlock khelp_list_lock;
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RW_SYSINIT(khelplistlock, &khelp_list_lock, "helper list lock");
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static TAILQ_HEAD(helper_head, helper) helpers = TAILQ_HEAD_INITIALIZER(helpers);
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/* Private function prototypes. */
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static inline void khelp_remove_osd(struct helper *h, struct osd *hosd);
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void khelp_new_hhook_registered(struct hhook_head *hhh, uint32_t flags);
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#define KHELP_LIST_WLOCK() rw_wlock(&khelp_list_lock)
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#define KHELP_LIST_WUNLOCK() rw_wunlock(&khelp_list_lock)
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#define KHELP_LIST_RLOCK() rw_rlock(&khelp_list_lock)
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#define KHELP_LIST_RUNLOCK() rw_runlock(&khelp_list_lock)
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#define KHELP_LIST_LOCK_ASSERT() rw_assert(&khelp_list_lock, RA_LOCKED)
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int
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khelp_register_helper(struct helper *h)
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{
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struct helper *tmph;
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int error, i, inserted;
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error = 0;
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inserted = 0;
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refcount_init(&h->h_refcount, 0);
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h->h_id = osd_register(OSD_KHELP, NULL, NULL);
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/* It's only safe to add the hooks after osd_register(). */
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if (h->h_nhooks > 0) {
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for (i = 0; i < h->h_nhooks && !error; i++) {
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/* We don't require the module to assign hook_helper. */
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h->h_hooks[i].hook_helper = h;
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error = hhook_add_hook_lookup(&h->h_hooks[i],
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HHOOK_WAITOK);
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}
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if (error) {
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for (i--; i >= 0; i--)
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hhook_remove_hook_lookup(&h->h_hooks[i]);
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osd_deregister(OSD_KHELP, h->h_id);
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}
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}
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if (!error) {
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KHELP_LIST_WLOCK();
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/*
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* Keep list of helpers sorted in descending h_id order. Due to
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* the way osd_set() works, a sorted list ensures
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* init_helper_osd() will operate with improved efficiency.
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*/
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TAILQ_FOREACH(tmph, &helpers, h_next) {
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if (tmph->h_id < h->h_id) {
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TAILQ_INSERT_BEFORE(tmph, h, h_next);
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inserted = 1;
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break;
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}
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}
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if (!inserted)
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TAILQ_INSERT_TAIL(&helpers, h, h_next);
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KHELP_LIST_WUNLOCK();
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}
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return (error);
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}
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int
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khelp_deregister_helper(struct helper *h)
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{
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struct helper *tmph;
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int error, i;
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error = 0;
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KHELP_LIST_WLOCK();
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if (h->h_refcount > 0)
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error = EBUSY;
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else {
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error = ENOENT;
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TAILQ_FOREACH(tmph, &helpers, h_next) {
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if (tmph == h) {
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TAILQ_REMOVE(&helpers, h, h_next);
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error = 0;
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break;
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}
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}
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}
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KHELP_LIST_WUNLOCK();
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if (!error) {
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if (h->h_nhooks > 0) {
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for (i = 0; i < h->h_nhooks; i++)
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hhook_remove_hook_lookup(&h->h_hooks[i]);
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}
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osd_deregister(OSD_KHELP, h->h_id);
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}
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return (error);
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}
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int
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khelp_init_osd(uint32_t classes, struct osd *hosd)
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{
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struct helper *h;
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void *hdata;
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int error;
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KASSERT(hosd != NULL, ("struct osd not initialised!"));
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error = 0;
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KHELP_LIST_RLOCK();
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TAILQ_FOREACH(h, &helpers, h_next) {
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/* If helper is correct class and needs to store OSD... */
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if (h->h_classes & classes && h->h_flags & HELPER_NEEDS_OSD) {
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hdata = uma_zalloc(h->h_zone, M_NOWAIT);
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if (hdata == NULL) {
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error = ENOMEM;
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break;
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}
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osd_set(OSD_KHELP, hosd, h->h_id, hdata);
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refcount_acquire(&h->h_refcount);
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}
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}
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if (error) {
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/* Delete OSD that was assigned prior to the error. */
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TAILQ_FOREACH(h, &helpers, h_next) {
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if (h->h_classes & classes)
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khelp_remove_osd(h, hosd);
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}
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}
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KHELP_LIST_RUNLOCK();
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return (error);
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}
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int
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khelp_destroy_osd(struct osd *hosd)
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{
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struct helper *h;
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int error;
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KASSERT(hosd != NULL, ("struct osd not initialised!"));
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error = 0;
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KHELP_LIST_RLOCK();
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/*
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* Clean up all khelp related OSD.
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*
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* XXXLAS: Would be nice to use something like osd_exit() here but it
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* doesn't have the right semantics for this purpose.
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*/
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TAILQ_FOREACH(h, &helpers, h_next)
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khelp_remove_osd(h, hosd);
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KHELP_LIST_RUNLOCK();
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return (error);
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}
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static inline void
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khelp_remove_osd(struct helper *h, struct osd *hosd)
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{
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void *hdata;
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if (h->h_flags & HELPER_NEEDS_OSD) {
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/*
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* If the current helper uses OSD and calling osd_get()
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* on the helper's h_id returns non-NULL, the helper has
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* OSD attached to 'hosd' which needs to be cleaned up.
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*/
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hdata = osd_get(OSD_KHELP, hosd, h->h_id);
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if (hdata != NULL) {
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uma_zfree(h->h_zone, hdata);
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osd_del(OSD_KHELP, hosd, h->h_id);
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refcount_release(&h->h_refcount);
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}
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}
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}
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void *
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khelp_get_osd(struct osd *hosd, int32_t id)
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{
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return (osd_get(OSD_KHELP, hosd, id));
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}
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int32_t
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khelp_get_id(char *hname)
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{
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struct helper *h;
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int32_t id;
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id = -1;
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KHELP_LIST_RLOCK();
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TAILQ_FOREACH(h, &helpers, h_next) {
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if (strncmp(h->h_name, hname, HELPER_NAME_MAXLEN) == 0) {
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id = h->h_id;
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break;
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}
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}
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KHELP_LIST_RUNLOCK();
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return (id);
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}
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int
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khelp_add_hhook(struct hookinfo *hki, uint32_t flags)
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{
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int error;
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/*
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* XXXLAS: Should probably include the functionality to update the
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* helper's h_hooks struct member.
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*/
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error = hhook_add_hook_lookup(hki, flags);
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return (error);
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}
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int
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khelp_remove_hhook(struct hookinfo *hki)
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{
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int error;
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/*
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* XXXLAS: Should probably include the functionality to update the
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* helper's h_hooks struct member.
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*/
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error = hhook_remove_hook_lookup(hki);
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return (error);
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}
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/*
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* Private KPI between hhook and khelp that allows khelp modules to insert hook
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* functions into hhook points which register after the modules were loaded.
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*/
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void
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khelp_new_hhook_registered(struct hhook_head *hhh, uint32_t flags)
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{
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struct helper *h;
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int error, i;
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KHELP_LIST_RLOCK();
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TAILQ_FOREACH(h, &helpers, h_next) {
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for (i = 0; i < h->h_nhooks; i++) {
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if (hhh->hhh_type != h->h_hooks[i].hook_type ||
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hhh->hhh_id != h->h_hooks[i].hook_id)
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continue;
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error = hhook_add_hook(hhh, &h->h_hooks[i], flags);
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if (error) {
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printf("%s: \"%s\" khelp module unable to "
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"hook type %d id %d due to error %d\n",
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__func__, h->h_name,
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h->h_hooks[i].hook_type,
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h->h_hooks[i].hook_id, error);
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error = 0;
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}
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}
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}
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KHELP_LIST_RUNLOCK();
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}
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int
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khelp_modevent(module_t mod, int event_type, void *data)
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{
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struct khelp_modevent_data *kmd;
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int error;
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kmd = (struct khelp_modevent_data *)data;
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error = 0;
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switch(event_type) {
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case MOD_LOAD:
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if (kmd->helper->h_flags & HELPER_NEEDS_OSD) {
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if (kmd->uma_zsize <= 0) {
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printf("Use KHELP_DECLARE_MOD_UMA() instead!\n");
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error = EDOOFUS;
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break;
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}
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kmd->helper->h_zone = uma_zcreate(kmd->name,
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kmd->uma_zsize, kmd->umactor, kmd->umadtor, NULL,
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NULL, 0, 0);
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if (kmd->helper->h_zone == NULL) {
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error = ENOMEM;
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break;
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}
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}
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strlcpy(kmd->helper->h_name, kmd->name, HELPER_NAME_MAXLEN);
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kmd->helper->h_hooks = kmd->hooks;
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kmd->helper->h_nhooks = kmd->nhooks;
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if (kmd->helper->mod_init != NULL)
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error = kmd->helper->mod_init();
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if (!error)
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error = khelp_register_helper(kmd->helper);
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break;
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case MOD_QUIESCE:
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case MOD_SHUTDOWN:
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case MOD_UNLOAD:
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error = khelp_deregister_helper(kmd->helper);
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if (!error) {
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if (kmd->helper->h_flags & HELPER_NEEDS_OSD)
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uma_zdestroy(kmd->helper->h_zone);
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if (kmd->helper->mod_destroy != NULL)
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kmd->helper->mod_destroy();
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} else if (error == ENOENT)
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/* Do nothing and allow unload if helper not in list. */
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error = 0;
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else if (error == EBUSY)
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printf("Khelp module \"%s\" can't unload until its "
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"refcount drops from %d to 0.\n", kmd->name,
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kmd->helper->h_refcount);
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break;
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default:
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error = EINVAL;
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break;
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}
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return (error);
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}
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