source: mainline/uspace/srv/sysman/sm_task.c@ 8d74fdd

/*
 * Copyright (c) 2015 Michal Koutny
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 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 <adt/list.h>
#include <errno.h>
#include <stdlib.h>
#include <task.h>
#include <sysman/unit.h>

#include "repo.h"
#include "log.h"
#include "sysman.h"
#include "sm_task.h"


/** Structure for boxing task event */
struct sm_task_event {
        task_id_t task_id;
        int flags;
        task_exit_t texit;
        int retval;
};

static void sysman_event_task_event(void *);

/**
 * @note This function runs in separate fibril (not same as event loop).
 */
static void sm_task_event_handler(task_id_t tid, int flags, task_exit_t texit,
    int retval)
{
        sm_task_event_t *tev = malloc(sizeof(sm_task_event_t));
        if (tev == NULL) {
                sysman_log(LVL_FATAL,
                    "Unable to process event of task %" PRIu64 ".", tid);
                return;
        }
        tev->task_id = tid;
        tev->flags = flags;
        tev->texit = texit;
        tev->retval = retval;

        sysman_raise_event(&sysman_event_task_event, tev);
}

static unit_svc_t *sm_task_find_service(task_id_t tid)
{
        /*
         * Unit to task is about to be developed, so use plain linear search
         * instead of specialized structures.
         */
        repo_foreach_t(UNIT_SERVICE, u) {
                if (CAST_SVC(u)->main_task_id == tid) {
                        return CAST_SVC(u);
                }

        }

        return NULL;
}

static unit_svc_t *sm_task_create_service(task_id_t tid)
{
        unit_t *u_svc = unit_create(UNIT_SERVICE);
        bool in_repo_update = false;
        int rc = EOK;

        if (u_svc == NULL) {
                goto fail;
        }

        rc = asprintf(&u_svc->name, ANONYMOUS_SERVICE_MASK "%c%s", tid,
            UNIT_NAME_SEPARATOR, UNIT_SVC_TYPE_NAME);
        if (rc < 0) {
                goto fail;
        }

        CAST_SVC(u_svc)->main_task_id = tid;
        CAST_SVC(u_svc)->anonymous = true;
        /* exec_start is left undefined, maybe could be hinted by kernel's task
         * name */

        /*
         * Temporary workaround to avoid killing ourselves during shutdown,
         * eventually should be captured by dependencies.
         */
        if (tid == task_get_id() || tid == 2 /*taskman*/) {
                CAST_SVC(u_svc)->critical = true;
        }

        repo_begin_update();
        in_repo_update = true;

        rc = repo_add_unit(u_svc);
        if (rc != EOK) {
                goto fail;
        }

        repo_commit();

        return CAST_SVC(u_svc);
        
fail:
        if (in_repo_update) {
                repo_rollback();
        }

        unit_destroy(&u_svc);
        return NULL;
}

static void sm_task_delete_service(unit_svc_t *u_svc)
{
        repo_begin_update();
        int rc = repo_remove_unit(&u_svc->unit);
        if (rc != EOK) {
                sysman_log(LVL_WARN, "Can't remove unit %s (%i).",
                    unit_name(&u_svc->unit), rc);
                repo_rollback();
                return;
        }

        repo_commit();
}

static void sysman_event_task_event(void *data)
{
        sm_task_event_t *tev = data;

        sysman_log(LVL_DEBUG2, "%s, %" PRIu64 " %i",
            __func__, tev->task_id, tev->flags);
        unit_svc_t *u_svc = sm_task_find_service(tev->task_id);

        if (u_svc == NULL) {
                if (tev->flags & TASK_WAIT_EXIT) {
                        /* Non-service task exited, ignore. */
                        goto finish;
                }

                u_svc = sm_task_create_service(tev->task_id);
                if (u_svc == NULL) {
                        sysman_log(LVL_WARN,
                            "Unable to create anonymous service for task %" PRIu64 ".",
                            tev->task_id);
                        goto finish;
                }

                sysman_log(LVL_DEBUG, "Created anonymous service %s.",
                    unit_name(&u_svc->unit));

                /* Inject state so that further processing makes sense */
                u_svc->unit.state = STATE_STARTING;
        }


        /* Simple incomplete state automaton */
        unit_t *u = &u_svc->unit;
        sysman_log(LVL_DEBUG2, "%s, %s(%i)@%" PRIu64 " %i",
            __func__, unit_name(u), u->state, tev->task_id, tev->flags);

        if (tev->flags & TASK_WAIT_EXIT) {
                // TODO maybe call unit_fail (would be nice to contain reason)
                //      or move this whole logic to unit_svc.c
                if (u->state == STATE_STOPPING) {
                        u->state = STATE_STOPPED;
                } else {
                        // if it has also retval == 0 then it's not fail
                        u->state = STATE_FAILED;
                }

        } else if (tev->flags & TASK_WAIT_RETVAL) {
                assert(u->state == STATE_STARTING);
                u->state = STATE_STARTED;
        }

        unit_notify_state(u);

        if ((tev->flags & TASK_WAIT_EXIT) && u_svc->anonymous) {
                sysman_log(LVL_DEBUG, "Deleted anonymous service %s.",
                    unit_name(&u_svc->unit));
                sm_task_delete_service(u_svc);
        }
finish:
        free(tev);
}

int sm_task_start(void)
{
        int rc = task_register_event_handler(&sm_task_event_handler, true);
        return rc;
}