modules/datalink_mod/datalink_mod.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright 2016 Nexenta Systems, Inc.
 */

/*
 * datalink syseventd module.
 *
 * The purpose of this module is to identify all datalink related events,
 * and react accordingly.
 */

#include <errno.h>
#include <sys/sysevent/eventdefs.h>
#include <string.h>
#include <libnvpair.h>
#include <librcm.h>
#include <libsysevent.h>
#include "sysevent_signal.h"

extern void syseventd_err_print(char *, ...);

struct event_list {
    nvlist_t *ev;
    struct event_list *next;
};

static rcm_handle_t *rcm_hdl = NULL;
static boolean_t dl_exiting;
static thread_t dl_notify_tid;
static mutex_t dl_mx;
static cond_t dl_cv;
static struct event_list *dl_events;

/* ARGSUSED */
static void *
datalink_notify_thread(void *arg)
{
    struct event_list *tmp_events, *ep;

    (void) mutex_lock(&dl_mx);

    while (! dl_exiting || dl_events != NULL) {
        if (dl_events == NULL) {
            (void) cond_wait(&dl_cv, &dl_mx);
            continue;
        }

        tmp_events = dl_events;
        dl_events = NULL;

        (void) mutex_unlock(&dl_mx);

        while (tmp_events != NULL) {
            struct sigaction cbuf, dfl;

            /*
             * Ignore SIGCLD for the
             * duration of the rcm_notify_event call.
             */
            (void) memset(&dfl, 0, sizeof (dfl));
            dfl.sa_handler = SIG_IGN;
            (void) sigaction(SIGCHLD, &dfl, &cbuf);

            /*
             * Send the PHYSLINK_NEW event to network_rcm to update
             * the network devices cache accordingly.
             */
            if (rcm_notify_event(rcm_hdl, RCM_RESOURCE_PHYSLINK_NEW,
                0, tmp_events->ev, NULL) != RCM_SUCCESS)
                syseventd_err_print("datalink_mod: Can not "
                    "notify event: %s\n", strerror(errno));

            (void) sigaction(SIGCHLD, &cbuf, NULL);
            ep = tmp_events;
            tmp_events = tmp_events->next;
            nvlist_free(ep->ev);
            free(ep);
        }

        (void) mutex_lock(&dl_mx);
    }

    (void) mutex_unlock(&dl_mx);

    return (NULL);
}

/*ARGSUSED*/
static int
datalink_deliver_event(sysevent_t *ev, int unused)
{
    const char *class = sysevent_get_class_name(ev);
    const char *subclass = sysevent_get_subclass_name(ev);
    nvlist_t *nvl;
    struct event_list *newp, **elpp;

    if (strcmp(class, EC_DATALINK) != 0 ||
        strcmp(subclass, ESC_DATALINK_PHYS_ADD) != 0) {
        return (0);
    }

    if (sysevent_get_attr_list(ev, &nvl) != 0)
        return (EINVAL);

    /*
     * rcm_notify_event() needs to be called asynchronously otherwise when
     * sysevent queue is full, deadlock will happen.
     */
    if ((newp = malloc(sizeof (struct event_list))) == NULL)
        return (ENOMEM);

    newp->ev = nvl;
    newp->next = NULL;

    /*
     * queue up at the end of the event list and signal notify_thread to
     * process it.
     */
    (void) mutex_lock(&dl_mx);
    elpp = &dl_events;
    while (*elpp !=  NULL)
        elpp = &(*elpp)->next;
    *elpp = newp;
    (void) cond_signal(&dl_cv);
    (void) mutex_unlock(&dl_mx);

    return (0);
}

static struct slm_mod_ops datalink_mod_ops = {
    SE_MAJOR_VERSION,
    SE_MINOR_VERSION,
    SE_MAX_RETRY_LIMIT,
    datalink_deliver_event
};

struct slm_mod_ops *
slm_init()
{
    dl_events = NULL;
    dl_exiting = B_FALSE;

    if (rcm_alloc_handle(NULL, 0, NULL, &rcm_hdl) != RCM_SUCCESS)
        return (NULL);

    (void) mutex_init(&dl_mx, USYNC_THREAD, NULL);
    (void) cond_init(&dl_cv, USYNC_THREAD, NULL);

    if (thr_create(NULL, 0,  datalink_notify_thread, NULL, 0,
        &dl_notify_tid) != 0) {
        (void) rcm_free_handle(rcm_hdl);
        (void) mutex_destroy(&dl_mx);
        (void) cond_destroy(&dl_cv);
        return (NULL);
    }

    return (&datalink_mod_ops);
}

void
slm_fini()
{
    (void) mutex_lock(&dl_mx);
    dl_exiting = B_TRUE;
    (void) cond_signal(&dl_cv);
    (void) mutex_unlock(&dl_mx);
    (void) thr_join(dl_notify_tid, NULL, NULL);

    (void) mutex_destroy(&dl_mx);
    (void) cond_destroy(&dl_cv);
    (void) rcm_free_handle(rcm_hdl);
    rcm_hdl = NULL;
}