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/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* SPDX-License-Identifier: MPL-2.0
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*! \file */
#include <inttypes.h>
#include <string.h>
#include <isc/atomic.h>
#include <isc/buffer.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/refcount.h>
#include <isc/stats.h>
#include <isc/util.h>
#define ISC_STATS_MAGIC ISC_MAGIC('S', 't', 'a', 't')
#define ISC_STATS_VALID(x) ISC_MAGIC_VALID(x, ISC_STATS_MAGIC)
/*
* Statistics are counted with an atomic int_fast64_t but exported to functions
* taking uint64_t (isc_stats_dumper_t). A 128-bit native and fast architecture
* doesn't exist in reality so these two are the same thing in practise.
* However, a silent truncation happening silently in the future is still not
* acceptable.
*/
STATIC_ASSERT(sizeof(isc_statscounter_t) <= sizeof(uint64_t),
"Exported statistics must fit into the statistic counter size");
struct isc_stats {
unsigned int magic;
isc_mem_t *mctx;
isc_refcount_t references;
int ncounters;
isc_atomic_statscounter_t *counters;
};
void
isc_stats_attach(isc_stats_t *stats, isc_stats_t **statsp) {
REQUIRE(ISC_STATS_VALID(stats));
REQUIRE(statsp != NULL && *statsp == NULL);
isc_refcount_increment(&stats->references);
*statsp = stats;
}
void
isc_stats_detach(isc_stats_t **statsp) {
isc_stats_t *stats;
REQUIRE(statsp != NULL && ISC_STATS_VALID(*statsp));
stats = *statsp;
*statsp = NULL;
if (isc_refcount_decrement(&stats->references) == 1) {
isc_refcount_destroy(&stats->references);
isc_mem_cput(stats->mctx, stats->counters, stats->ncounters,
sizeof(isc_atomic_statscounter_t));
isc_mem_putanddetach(&stats->mctx, stats, sizeof(*stats));
}
}
int
isc_stats_ncounters(isc_stats_t *stats) {
REQUIRE(ISC_STATS_VALID(stats));
return stats->ncounters;
}
void
isc_stats_create(isc_mem_t *mctx, isc_stats_t **statsp, int ncounters) {
REQUIRE(statsp != NULL && *statsp == NULL);
isc_stats_t *stats = isc_mem_get(mctx, sizeof(*stats));
size_t counters_alloc_size = sizeof(isc_atomic_statscounter_t) *
ncounters;
stats->counters = isc_mem_get(mctx, counters_alloc_size);
isc_refcount_init(&stats->references, 1);
for (int i = 0; i < ncounters; i++) {
atomic_init(&stats->counters[i], 0);
}
stats->mctx = NULL;
isc_mem_attach(mctx, &stats->mctx);
stats->ncounters = ncounters;
stats->magic = ISC_STATS_MAGIC;
*statsp = stats;
}
isc_statscounter_t
isc_stats_increment(isc_stats_t *stats, isc_statscounter_t counter) {
REQUIRE(ISC_STATS_VALID(stats));
REQUIRE(counter < stats->ncounters);
return atomic_fetch_add_relaxed(&stats->counters[counter], 1);
}
void
isc_stats_decrement(isc_stats_t *stats, isc_statscounter_t counter) {
REQUIRE(ISC_STATS_VALID(stats));
REQUIRE(counter < stats->ncounters);
#if ISC_STATS_CHECKUNDERFLOW
REQUIRE(atomic_fetch_sub_release(&stats->counters[counter], 1) > 0);
#else
atomic_fetch_sub_release(&stats->counters[counter], 1);
#endif
}
void
isc_stats_dump(isc_stats_t *stats, isc_stats_dumper_t dump_fn, void *arg,
unsigned int options) {
int i;
REQUIRE(ISC_STATS_VALID(stats));
for (i = 0; i < stats->ncounters; i++) {
isc_statscounter_t counter =
atomic_load_acquire(&stats->counters[i]);
if ((options & ISC_STATSDUMP_VERBOSE) == 0 && counter == 0) {
continue;
}
dump_fn((isc_statscounter_t)i, counter, arg);
}
}
void
isc_stats_set(isc_stats_t *stats, uint64_t val, isc_statscounter_t counter) {
REQUIRE(ISC_STATS_VALID(stats));
REQUIRE(counter < stats->ncounters);
atomic_store_release(&stats->counters[counter], val);
}
void
isc_stats_update_if_greater(isc_stats_t *stats, isc_statscounter_t counter,
isc_statscounter_t value) {
REQUIRE(ISC_STATS_VALID(stats));
REQUIRE(counter < stats->ncounters);
isc_statscounter_t curr_value =
atomic_load_acquire(&stats->counters[counter]);
do {
if (curr_value >= value) {
break;
}
} while (!atomic_compare_exchange_weak_acq_rel(
&stats->counters[counter], &curr_value, value));
}
isc_statscounter_t
isc_stats_get_counter(isc_stats_t *stats, isc_statscounter_t counter) {
REQUIRE(ISC_STATS_VALID(stats));
REQUIRE(counter < stats->ncounters);
return atomic_load_acquire(&stats->counters[counter]);
}
void
isc_stats_resize(isc_stats_t **statsp, int ncounters) {
isc_stats_t *stats;
size_t counters_alloc_size;
isc_atomic_statscounter_t *newcounters;
REQUIRE(statsp != NULL && *statsp != NULL);
REQUIRE(ISC_STATS_VALID(*statsp));
REQUIRE(ncounters > 0);
stats = *statsp;
if (stats->ncounters >= ncounters) {
/* We already have enough counters. */
return;
}
/* Grow number of counters. */
counters_alloc_size = sizeof(isc_atomic_statscounter_t) * ncounters;
newcounters = isc_mem_get(stats->mctx, counters_alloc_size);
for (int i = 0; i < ncounters; i++) {
atomic_init(&newcounters[i], 0);
}
for (int i = 0; i < stats->ncounters; i++) {
uint32_t counter = atomic_load_acquire(&stats->counters[i]);
atomic_store_release(&newcounters[i], counter);
}
isc_mem_cput(stats->mctx, stats->counters, stats->ncounters,
sizeof(isc_atomic_statscounter_t));
stats->counters = newcounters;
stats->ncounters = ncounters;
}
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