source: mainline/uspace/srv/sysman/repo.c@ aa0faeca

/*
 * 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/hash.h>
#include <adt/hash_table.h>
#include <adt/list.h>
#include <str.h>
#include <assert.h>
#include <errno.h>
#include <fibril_synch.h>

#include "repo.h"
#include "edge.h"
#include "log.h"

LIST_INITIALIZE(units_);

static hash_table_t units_by_name;
static hash_table_t units_by_handle;
/** Lock to protect units_by_name and units_by_handle, so that
 * repo_find_unit_by_* can be called also from non-event loop fibrils.
 */
static FIBRIL_RWLOCK_INITIALIZE(repo_lock);

/* Hash table functions */
static size_t units_by_handle_ht_hash(const ht_link_t *item)
{
        unit_t *unit =
            hash_table_get_inst(item, unit_t, units_by_handle);
        return unit->handle;
}

static size_t units_by_handle_ht_key_hash(const void *key)
{
        return *(unit_handle_t *)key;
}

static bool units_by_handle_ht_equal(const ht_link_t *item1, const ht_link_t *item2)
{
        return
            hash_table_get_inst(item1, unit_t, units_by_handle) ==
            hash_table_get_inst(item2, unit_t, units_by_handle);
}

static bool units_by_handle_ht_key_equal(const void *key, const ht_link_t *item)
{
        return *(unit_handle_t *)key ==
            hash_table_get_inst(item, unit_t, units_by_handle)->handle;
}

static hash_table_ops_t units_by_handle_ht_ops = {
        .hash            = &units_by_handle_ht_hash,
        .key_hash        = &units_by_handle_ht_key_hash,
        .equal           = &units_by_handle_ht_equal,
        .key_equal       = &units_by_handle_ht_key_equal,
        .remove_callback = NULL
};

static size_t units_by_name_ht_hash(const ht_link_t *item)
{
        unit_t *unit =
            hash_table_get_inst(item, unit_t, units_by_name);
        return hash_string(unit->name);
}

static size_t units_by_name_ht_key_hash(const void *key)
{
        return hash_string((const char *)key);
}

static bool units_by_name_ht_equal(const ht_link_t *item1, const ht_link_t *item2)
{
        return
            hash_table_get_inst(item1, unit_t, units_by_handle) ==
            hash_table_get_inst(item2, unit_t, units_by_handle);
}

static bool units_by_name_ht_key_equal(const void *key, const ht_link_t *item)
{
        return str_cmp((const char *)key,
            hash_table_get_inst(item, unit_t, units_by_name)->name) == 0;
}

static hash_table_ops_t units_by_name_ht_ops = {
        .hash            = &units_by_name_ht_hash,
        .key_hash        = &units_by_name_ht_key_hash,
        .equal           = &units_by_name_ht_equal,
        .key_equal       = &units_by_name_ht_key_equal,
        .remove_callback = NULL
};

/* Repository functions */

static void repo_remove_unit_internal(unit_t *u)
{
        assert(fibril_rwlock_is_write_locked(&repo_lock));

        hash_table_remove_item(&units_by_name, &u->units_by_name);
        hash_table_remove_item(&units_by_handle, &u->units_by_handle);
        list_remove(&u->units);

        // TODO decrease refcount of unit
        // unit may be referenced e.g. from running job, thus we cannot simply destroy it
}

static unit_t *repo_find_unit_by_name_internal(const char *name, bool lock)
{
        sysman_log(LVL_DEBUG2, "%s(%s, %i)", __func__, name, lock);
        if (lock)
                fibril_rwlock_read_lock(&repo_lock);
        ht_link_t *ht_link = hash_table_find(&units_by_name, (void *)name);
        if (lock)
                fibril_rwlock_read_unlock(&repo_lock);

        if (ht_link != NULL) {
                return hash_table_get_inst(ht_link, unit_t, units_by_name);
        } else {
                return NULL;
        }
}

void repo_init(void)
{
        hash_table_create(&units_by_name, 0, 0, &units_by_name_ht_ops);
        hash_table_create(&units_by_handle, 0, 0, &units_by_handle_ht_ops);
}

errno_t repo_add_unit(unit_t *unit)
{
        assert(unit);
        assert(unit->repo_state == REPO_EMBRYO);
        assert(unit->handle == 0);
        assert(unit->name != NULL);
        assert(fibril_rwlock_is_write_locked(&repo_lock));
        sysman_log(LVL_DEBUG2, "%s('%s')", __func__, unit_name(unit));

        if (hash_table_insert_unique(&units_by_name, &unit->units_by_name)) {
                /* Pointers are same size as unit_handle_t both on 32b and 64b */
                unit->handle = (unit_handle_t)unit;

                hash_table_insert(&units_by_handle, &unit->units_by_handle);
                list_append(&unit->units, &units_);
                return EOK;
        } else {
                return EEXIST;
        }
}

errno_t repo_remove_unit(unit_t *unit)
{
        unit->repo_state = REPO_ZOMBIE;
        return EOK; /* We could check that unit is present in repo etc... */
}

void repo_begin_update(void)
{
        sysman_log(LVL_DEBUG2, "%s", __func__);
        fibril_rwlock_write_lock(&repo_lock);
}

static bool repo_commit_unit(ht_link_t *ht_link, void *arg)
{
        unit_t *unit = hash_table_get_inst(ht_link, unit_t, units_by_name);
        if (unit->repo_state == REPO_ZOMBIE) {
                repo_remove_unit_internal(unit);
                return true;
        }

        if (unit->repo_state == REPO_EMBRYO) {
                unit->repo_state = REPO_LIVING;
        }

        list_foreach(unit->edges_out, edges_out, unit_edge_t, e) {
                e->commited = true;
        }
        return true;
}

/** Marks newly added units_by_name as usable (via state change) */
void repo_commit(void)
{
        sysman_log(LVL_DEBUG2, "%s", __func__);

        /*
         * Apply commit to all units_by_name, each commited unit commits its
         * outgoing deps, thus eventually commiting all embryo deps as well.
         *
         * TODO why not iterate over units list?
         */
        hash_table_apply(&units_by_name, &repo_commit_unit, NULL);
        fibril_rwlock_write_unlock(&repo_lock);
}

static bool repo_rollback_unit(ht_link_t *ht_link, void *arg)
{
        unit_t *unit = hash_table_get_inst(ht_link, unit_t, units_by_name);

        list_foreach_safe(unit->edges_out, cur_link, next_link) {
                unit_edge_t *e =
                    list_get_instance(cur_link, unit_edge_t, edges_out);
                if (!e->commited) {
                        edge_remove(&e);
                }
        }

        if (unit->repo_state == REPO_EMBRYO) {
                repo_remove_unit_internal(unit);
        } else if (unit->repo_state == REPO_ZOMBIE) {
                unit->repo_state = REPO_LIVING;
        }

        return true;
}

/** Remove all uncommited units_by_name and edges from configuratio
 *
 * Memory used by removed object is released.
 */
void repo_rollback(void)
{
        sysman_log(LVL_DEBUG2, "%s", __func__);

        hash_table_apply(&units_by_name, &repo_rollback_unit, NULL);
        fibril_rwlock_write_unlock(&repo_lock);
}

static bool repo_resolve_unit(ht_link_t *ht_link, void *arg)
{
        bool *has_error_ptr = arg;
        unit_t *unit = hash_table_get_inst(ht_link, unit_t, units_by_name);

        list_foreach(unit->edges_out, edges_out, unit_edge_t, e) {
                assert(e->input == unit);
                assert((e->output != NULL) != (e->output_name != NULL));
                if (e->output) {
                        continue;
                }

                unit_t *output =
                    repo_find_unit_by_name_unsafe(e->output_name);
                if (output == NULL) {
                        sysman_log(LVL_ERROR,
                            "Cannot resolve dependency of '%s' to unit '%s'",
                            unit_name(unit), e->output_name);
                        *has_error_ptr = true;
                        // TODO should we just leave the sprout untouched?
                } else {
                        edge_resolve_output(e, output);
                }
        }

        return true;
}

static bool repo_clean_up_unit(ht_link_t *ht_link, void *arg)
{
        unit_t *unit = hash_table_get_inst(ht_link, unit_t, units_by_name);

        if (unit->conditions != UNIT_CONDITION_NONE) {
                unit_log_condition(unit);

                list_foreach_safe(unit->edges_in, current_link, iter) {
                        unit_edge_t *e = list_get_instance(current_link, unit_edge_t, edges_in);
                        edge_remove(&e);
                }

                list_foreach_safe(unit->edges_out, current_link, iter) {
                        unit_edge_t *e = list_get_instance(current_link, unit_edge_t, edges_out);
                        edge_remove(&e);
                }
        }

        return true;
}

/** Resolve unresolved dependencies between any pair of units_by_name
 *
 * @return EOK      on success
 * @return ENOENT  when one or more resolution fails, information is logged
 */
errno_t repo_resolve_references(void)
{
        sysman_log(LVL_DEBUG2, "%s", __func__);

        bool has_error = false;
        hash_table_apply(&units_by_name, &repo_resolve_unit, &has_error);

        if (!has_error) {
                //once all references have been built test if there are
                //units which dont meet the conditions. If yes, remove the edges
                hash_table_apply(&units_by_name, &repo_clean_up_unit, &has_error);
        }

        return has_error ? ENOENT : EOK;
}

/**
 * The function can be safely called from non-event loop fibrils
 */
unit_t *repo_find_unit_by_name(const char *name)
{
        return repo_find_unit_by_name_internal(name, true);
}

/**
 * @note Caller must hold repo_lock (at least reader)
 */
unit_t *repo_find_unit_by_name_unsafe(const char *name)
{
        return repo_find_unit_by_name_internal(name, false);
}

/**
 * The function can be safely called from non-event loop fibrils
 */
unit_t *repo_find_unit_by_handle(unit_handle_t handle)
{
        sysman_log(LVL_DEBUG2, "%s", __func__);
        fibril_rwlock_read_lock(&repo_lock);
        ht_link_t *ht_link = hash_table_find(&units_by_handle, &handle);
        fibril_rwlock_read_unlock(&repo_lock);

        if (ht_link != NULL) {
                return hash_table_get_inst(ht_link, unit_t, units_by_handle);
        } else {
                return NULL;
        }
}

void repo_rlock(void)
{
        sysman_log(LVL_DEBUG2, "%s", __func__);
        fibril_rwlock_read_lock(&repo_lock);
}

void repo_runlock(void)
{
        sysman_log(LVL_DEBUG2, "%s", __func__);
        fibril_rwlock_read_unlock(&repo_lock);
}