| /*! \file stat_item.c |
| * utility routines for keeping statistical values */ |
| /* |
| * (C) 2009-2010 by Harald Welte <laforge@gnumonks.org> |
| * (C) 2015 by sysmocom - s.f.m.c. GmbH |
| * |
| * All Rights Reserved |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| */ |
| |
| /*! \addtogroup osmo_stat_item |
| * @{ |
| * |
| * This osmo_stat_item module adds instrumentation capabilities to |
| * gather measurement and statistical values in a similar fashion to |
| * what we have as \ref osmo_counter_group. |
| * |
| * As opposed to counters, osmo_stat_item do not increment but consist |
| * of a configurable-sized FIFO, which can store not only the current |
| * (most recent) value, but also historic values. |
| * |
| * The only supported value type is an int32_t. |
| * |
| * Getting values from the osmo_stat_item does not modify its state to |
| * allow for multiple independent back-ends retrieving values (e.g. VTY |
| * and statd). |
| * |
| * Each value stored in the FIFO of an osmo_stat_item has an associated |
| * value_id. The value_id is derived from an application-wide globally |
| * incrementing counter, so (until the counter wraps) more recent |
| * values will have higher values. |
| * |
| * When a new value is set, the oldest value in the FIFO gets silently |
| * overwritten. Lost values are skipped when getting values from the |
| * item. |
| * |
| */ |
| |
| #include <stdint.h> |
| #include <string.h> |
| |
| #include <osmocom/core/utils.h> |
| #include <osmocom/core/linuxlist.h> |
| #include <osmocom/core/talloc.h> |
| #include <osmocom/core/timer.h> |
| #include <osmocom/core/stat_item.h> |
| |
| /*! global list of stat_item groups */ |
| static LLIST_HEAD(osmo_stat_item_groups); |
| /*! counter for assigning globally unique value identifiers */ |
| static int32_t global_value_id = 0; |
| |
| /*! talloc context from which we allocate */ |
| static void *tall_stat_item_ctx; |
| |
| /*! Allocate a new group of counters according to description. |
| * Allocate a group of stat items described in \a desc from talloc context \a ctx, |
| * giving the new group the index \a idx. |
| * \param[in] ctx \ref talloc context |
| * \param[in] desc Statistics item group description |
| * \param[in] idx Index of new stat item group |
| */ |
| struct osmo_stat_item_group *osmo_stat_item_group_alloc(void *ctx, |
| const struct osmo_stat_item_group_desc *desc, |
| unsigned int idx) |
| { |
| unsigned int group_size; |
| unsigned long items_size = 0; |
| unsigned int item_idx; |
| void *items; |
| |
| struct osmo_stat_item_group *group; |
| |
| group_size = sizeof(struct osmo_stat_item_group) + |
| desc->num_items * sizeof(struct osmo_stat_item *); |
| |
| if (!ctx) |
| ctx = tall_stat_item_ctx; |
| |
| group = talloc_zero_size(ctx, group_size); |
| if (!group) |
| return NULL; |
| |
| group->desc = desc; |
| group->idx = idx; |
| |
| /* Get combined size of all items */ |
| for (item_idx = 0; item_idx < desc->num_items; item_idx++) { |
| unsigned int size; |
| size = sizeof(struct osmo_stat_item) + |
| sizeof(struct osmo_stat_item_value) * |
| desc->item_desc[item_idx].num_values; |
| /* Align to pointer size */ |
| size = (size + sizeof(void *) - 1) & ~(sizeof(void *) - 1); |
| |
| /* Store offsets into the item array */ |
| group->items[item_idx] = (void *)items_size; |
| |
| items_size += size; |
| } |
| |
| items = talloc_zero_size(group, items_size); |
| if (!items) { |
| talloc_free(group); |
| return NULL; |
| } |
| |
| /* Update item pointers */ |
| for (item_idx = 0; item_idx < desc->num_items; item_idx++) { |
| struct osmo_stat_item *item = (struct osmo_stat_item *) |
| ((uint8_t *)items + (unsigned long)group->items[item_idx]); |
| unsigned int i; |
| |
| group->items[item_idx] = item; |
| item->last_offs = desc->item_desc[item_idx].num_values - 1; |
| item->last_value_index = -1; |
| item->desc = &desc->item_desc[item_idx]; |
| |
| for (i = 0; i <= item->last_offs; i++) { |
| item->values[i].value = desc->item_desc[item_idx].default_value; |
| item->values[i].id = OSMO_STAT_ITEM_NOVALUE_ID; |
| } |
| } |
| |
| llist_add(&group->list, &osmo_stat_item_groups); |
| |
| return group; |
| } |
| |
| /*! Free the memory for the specified group of stat items */ |
| void osmo_stat_item_group_free(struct osmo_stat_item_group *grp) |
| { |
| llist_del(&grp->list); |
| talloc_free(grp); |
| } |
| |
| /*! Set the a given stat_item to the given value. |
| * This function adds a new value for the given stat_item at the end of |
| * the FIFO. |
| * \param[in] item The stat_item whose \a value we want to set |
| * \param[in] value The numeric value we want to store at end of FIFO |
| */ |
| void osmo_stat_item_set(struct osmo_stat_item *item, int32_t value) |
| { |
| item->last_offs += 1; |
| if (item->last_offs >= item->desc->num_values) |
| item->last_offs = 0; |
| |
| global_value_id += 1; |
| if (global_value_id == OSMO_STAT_ITEM_NOVALUE_ID) |
| global_value_id += 1; |
| |
| item->values[item->last_offs].value = value; |
| item->values[item->last_offs].id = global_value_id; |
| } |
| |
| /*! Retrieve the next value from the osmo_stat_item object. |
| * If a new value has been set, it is returned. The idx is used to decide |
| * which value to return. |
| * On success, *idx is updated to refer to the next unread value. If |
| * values have been missed due to FIFO overflow, *idx is incremented by |
| * (1 + num_lost). |
| * This way, the osmo_stat_item object can be kept stateless from the reader's |
| * perspective and therefore be used by several backends simultaneously. |
| * |
| * \param val the osmo_stat_item object |
| * \param idx identifies the next value to be read |
| * \param value a pointer to store the value |
| * \returns the increment of the index (0: no value has been read, |
| * 1: one value has been taken, |
| * (1+n): n values have been skipped, one has been taken) |
| */ |
| int osmo_stat_item_get_next(const struct osmo_stat_item *item, int32_t *next_idx, |
| int32_t *value) |
| { |
| const struct osmo_stat_item_value *next_value; |
| const struct osmo_stat_item_value *item_value = NULL; |
| int idx_delta; |
| int next_offs; |
| |
| next_offs = item->last_offs; |
| next_value = &item->values[next_offs]; |
| |
| while (next_value->id - *next_idx >= 0 && |
| next_value->id != OSMO_STAT_ITEM_NOVALUE_ID) |
| { |
| item_value = next_value; |
| |
| next_offs -= 1; |
| if (next_offs < 0) |
| next_offs = item->desc->num_values - 1; |
| if (next_offs == item->last_offs) |
| break; |
| next_value = &item->values[next_offs]; |
| } |
| |
| if (!item_value) |
| /* All items have been read */ |
| return 0; |
| |
| *value = item_value->value; |
| |
| idx_delta = item_value->id + 1 - *next_idx; |
| |
| *next_idx = item_value->id + 1; |
| |
| return idx_delta; |
| } |
| |
| /*! Skip/discard all values of this item and update \a idx accordingly */ |
| int osmo_stat_item_discard(const struct osmo_stat_item *item, int32_t *idx) |
| { |
| int discarded = item->values[item->last_offs].id + 1 - *idx; |
| *idx = item->values[item->last_offs].id + 1; |
| |
| return discarded; |
| } |
| |
| /*! Skip all values of all items and update \a idx accordingly */ |
| int osmo_stat_item_discard_all(int32_t *idx) |
| { |
| int discarded = global_value_id + 1 - *idx; |
| *idx = global_value_id + 1; |
| |
| return discarded; |
| } |
| |
| /*! Initialize the stat item module. Call this once from your program. |
| * \param[in] tall_ctx Talloc context from which this module allocates */ |
| int osmo_stat_item_init(void *tall_ctx) |
| { |
| tall_stat_item_ctx = tall_ctx; |
| |
| return 0; |
| } |
| |
| /*! Search for item group based on group name and index |
| * \param[in] name Name of stats_item_group we want to find |
| * \param[in] idx Index of the group we want to find |
| * \returns pointer to group, if found; NULL otherwise */ |
| struct osmo_stat_item_group *osmo_stat_item_get_group_by_name_idx( |
| const char *name, const unsigned int idx) |
| { |
| struct osmo_stat_item_group *statg; |
| |
| llist_for_each_entry(statg, &osmo_stat_item_groups, list) { |
| if (!statg->desc) |
| continue; |
| |
| if (!strcmp(statg->desc->group_name_prefix, name) && |
| statg->idx == idx) |
| return statg; |
| } |
| return NULL; |
| } |
| |
| /*! Search for item based on group + item name |
| * \param[in] statg group in which to search for the item |
| * \param[in] name name of item to search within \a statg |
| * \returns pointer to item, if found; NULL otherwise */ |
| const struct osmo_stat_item *osmo_stat_item_get_by_name( |
| const struct osmo_stat_item_group *statg, const char *name) |
| { |
| int i; |
| const struct osmo_stat_item_desc *item_desc; |
| |
| if (!statg->desc) |
| return NULL; |
| |
| for (i = 0; i < statg->desc->num_items; i++) { |
| item_desc = &statg->desc->item_desc[i]; |
| |
| if (!strcmp(item_desc->name, name)) { |
| return statg->items[i]; |
| } |
| } |
| return NULL; |
| } |
| |
| /*! Iterate over all items in group, call user-supplied function on each |
| * \param[in] statg stat_item group over whose items to iterate |
| * \param[in] handle_item Call-back function, aborts if rc < 0 |
| * \param[in] data Private data handed through to \a handle_item |
| */ |
| int osmo_stat_item_for_each_item(struct osmo_stat_item_group *statg, |
| osmo_stat_item_handler_t handle_item, void *data) |
| { |
| int rc = 0; |
| int i; |
| |
| for (i = 0; i < statg->desc->num_items; i++) { |
| struct osmo_stat_item *item = statg->items[i]; |
| rc = handle_item(statg, item, data); |
| if (rc < 0) |
| return rc; |
| } |
| |
| return rc; |
| } |
| |
| /*! Iterate over all stat_item groups in system, call user-supplied function on each |
| * \param[in] handle_group Call-back function, aborts if rc < 0 |
| * \param[in] data Private data handed through to \a handle_group |
| */ |
| int osmo_stat_item_for_each_group(osmo_stat_item_group_handler_t handle_group, void *data) |
| { |
| struct osmo_stat_item_group *statg; |
| int rc = 0; |
| |
| llist_for_each_entry(statg, &osmo_stat_item_groups, list) { |
| rc = handle_group(statg, data); |
| if (rc < 0) |
| return rc; |
| } |
| |
| return rc; |
| } |
| |
| /*! @} */ |