+/*
+ * Copyright (C) 2012 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#define _LGPL_SOURCE
+#include <algorithm>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include <common/defaults.h>
+#include <common/error.h>
+#include <common/macros.h>
+#include <common/sessiond-comm/inet.h>
+
+#include <lttng/health-internal.h>
+
+/*
+ * An application-specific error state for unregistered thread keeps
+ * track of thread errors. A thread reporting a health error, normally
+ * unregisters and quits. This makes the TLS health state not available
+ * to the health_check_state() call so on unregister we update this
+ * global error array so we can keep track of which thread was on error
+ * if the TLS health state has been removed.
+ */
+struct health_app {
+ /* List of health state, for each application thread */
+ struct cds_list_head list;
+ /*
+ * This lock ensures that TLS memory used for the node and its
+ * container structure don't get reclaimed after the TLS owner
+ * thread exits until we have finished using it.
+ */
+ pthread_mutex_t lock;
+ int nr_types;
+ struct timespec time_delta;
+ /* Health flags containing thread type error state */
+ enum health_flags *flags;
+};
+
+/* Define TLS health state. */
+DEFINE_URCU_TLS(struct health_state, health_state);
+
+/*
+ * Initialize health check subsytem.
+ */
+static
+void health_init(struct health_app *ha)
+{
+ /*
+ * Get the maximum value between the default delta value and the TCP
+ * timeout with a safety net of the default health check delta.
+ */
+ ha->time_delta.tv_sec = std::max<unsigned long>(
+ lttcomm_inet_tcp_timeout + DEFAULT_HEALTH_CHECK_DELTA_S,
+ ha->time_delta.tv_sec);
+ DBG("Health check time delta in seconds set to %lu",
+ ha->time_delta.tv_sec);
+}
+
+struct health_app *health_app_create(int nr_types)
+{
+ struct health_app *ha;
+
+ ha = (health_app *) zmalloc(sizeof(*ha));
+ if (!ha) {
+ return NULL;
+ }
+ ha->flags = (health_flags *) zmalloc(sizeof(*ha->flags) * nr_types);
+ if (!ha->flags) {
+ goto error_flags;
+ }
+ CDS_INIT_LIST_HEAD(&ha->list);
+ pthread_mutex_init(&ha->lock, NULL);
+ ha->nr_types = nr_types;
+ ha->time_delta.tv_sec = DEFAULT_HEALTH_CHECK_DELTA_S;
+ ha->time_delta.tv_nsec = DEFAULT_HEALTH_CHECK_DELTA_NS;
+ health_init(ha);
+ return ha;
+
+error_flags:
+ free(ha);
+ return NULL;
+}
+
+void health_app_destroy(struct health_app *ha)
+{
+ free(ha->flags);
+ free(ha);
+}
+
+/*
+ * Lock health state global list mutex.
+ */
+static void state_lock(struct health_app *ha)
+{
+ pthread_mutex_lock(&ha->lock);
+}
+
+/*
+ * Unlock health state global list mutex.
+ */
+static void state_unlock(struct health_app *ha)
+{
+ pthread_mutex_unlock(&ha->lock);
+}
+
+/*
+ * Set time difference in res from time_a and time_b.
+ */
+static void time_diff(const struct timespec *time_a,
+ const struct timespec *time_b, struct timespec *res)
+{
+ if (time_a->tv_nsec - time_b->tv_nsec < 0) {
+ res->tv_sec = time_a->tv_sec - time_b->tv_sec - 1;
+ res->tv_nsec = 1000000000L + time_a->tv_sec - time_b->tv_sec;
+ } else {
+ res->tv_sec = time_a->tv_sec - time_b->tv_sec;
+ res->tv_nsec = time_a->tv_nsec - time_b->tv_nsec;
+ }
+}
+
+/*
+ * Return true if time_a - time_b > diff, else false.
+ */
+static int time_diff_gt(const struct timespec *time_a,
+ const struct timespec *time_b, const struct timespec *diff)
+{
+ struct timespec res;
+
+ time_diff(time_a, time_b, &res);
+ time_diff(&res, diff, &res);
+
+ if (res.tv_sec > 0) {
+ return 1;
+ } else if (res.tv_sec == 0 && res.tv_nsec > 0) {
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * Validate health state. Checks for the error flag or health conditions.
+ *
+ * Return 0 if health is bad or else 1.
+ */
+static int validate_state(struct health_app *ha, struct health_state *state)
+{
+ int retval = 1, ret;
+ unsigned long current, last;
+ struct timespec current_time;
+
+ LTTNG_ASSERT(state);
+
+ last = state->last;
+ current = uatomic_read(&state->current);
+
+ ret = lttng_clock_gettime(CLOCK_MONOTONIC, ¤t_time);
+ if (ret < 0) {
+ PERROR("Error reading time\n");
+ /* error */
+ retval = 0;
+ goto end;
+ }
+
+ /*
+ * Thread is in bad health if flag HEALTH_ERROR is set. It is also in bad
+ * health if, after the delta delay has passed, its the progress counter
+ * has not moved and it has NOT been waiting for a poll() call.
+ */
+ if (uatomic_read(&state->flags) & HEALTH_ERROR) {
+ retval = 0;
+ goto end;
+ }
+
+ /*
+ * Initial condition need to update the last counter and sample time, but
+ * should not check health in this initial case, because we don't know how
+ * much time has passed.
+ */
+ if (state->last_time.tv_sec == 0 && state->last_time.tv_nsec == 0) {
+ /* update last counter and last sample time */
+ state->last = current;
+ memcpy(&state->last_time, ¤t_time, sizeof(current_time));
+ } else {
+ if (time_diff_gt(¤t_time, &state->last_time,
+ &ha->time_delta)) {
+ if (current == last && !HEALTH_IS_IN_POLL(current)) {
+ /* error */
+ retval = 0;
+ }
+ /* update last counter and last sample time */
+ state->last = current;
+ memcpy(&state->last_time, ¤t_time, sizeof(current_time));
+
+ /* On error, stop right now and notify caller. */
+ if (retval == 0) {
+ goto end;
+ }
+ }
+ }
+
+end:
+ DBG("Health state current %lu, last %lu, ret %d",
+ current, last, ret);
+ return retval;
+}
+
+/*
+ * Check health of a specific health type. Note that if a thread has not yet
+ * initialize its health subsystem or has quit, it's considered in a good
+ * state.
+ *
+ * Return 0 if health is bad or else 1.
+ */
+int health_check_state(struct health_app *ha, int type)
+{
+ int retval = 1;
+ struct health_state *state;
+
+ LTTNG_ASSERT(type < ha->nr_types);
+
+ state_lock(ha);
+
+ cds_list_for_each_entry(state, &ha->list, node) {
+ int ret;
+
+ if (state->type != type) {
+ continue;
+ }
+
+ ret = validate_state(ha, state);
+ if (!ret) {
+ retval = 0;
+ goto end;
+ }
+ }
+
+ /* Check the global state since some state might not be visible anymore. */
+ if (ha->flags[type] & HEALTH_ERROR) {
+ retval = 0;
+ }
+
+end:
+ state_unlock(ha);
+
+ DBG("Health check for type %d is %s", (int) type,
+ (retval == 0) ? "BAD" : "GOOD");
+ return retval;
+}
+
+/*
+ * Init health state.
+ */
+void health_register(struct health_app *ha, int type)
+{
+ LTTNG_ASSERT(type < ha->nr_types);
+
+ /* Init TLS state. */
+ uatomic_set(&URCU_TLS(health_state).last, 0);
+ uatomic_set(&URCU_TLS(health_state).last_time.tv_sec, 0);
+ uatomic_set(&URCU_TLS(health_state).last_time.tv_nsec, 0);
+ uatomic_set(&URCU_TLS(health_state).current, 0);
+ uatomic_set(&URCU_TLS(health_state).flags, (health_flags) 0);
+ uatomic_set(&URCU_TLS(health_state).type, type);
+
+ /* Add it to the global TLS state list. */
+ state_lock(ha);
+ cds_list_add(&URCU_TLS(health_state).node, &ha->list);
+ state_unlock(ha);
+}
+
+/*
+ * Remove node from global list.
+ */
+void health_unregister(struct health_app *ha)
+{
+ state_lock(ha);
+ /*
+ * On error, set the global_error_state since we are about to remove
+ * the node from the global list.
+ */
+ if (uatomic_read(&URCU_TLS(health_state).flags) & HEALTH_ERROR) {
+ uatomic_set(&ha->flags[URCU_TLS(health_state).type],
+ HEALTH_ERROR);
+ }
+ cds_list_del(&URCU_TLS(health_state).node);
+ state_unlock(ha);
+}
projects / lttng-tools.git / blobdiff