--- /dev/null
+/*
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * LTTng UST application context provider.
+ */
+
+#define _LGPL_SOURCE
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <common/ust-context-provider.h>
+
+#include "context-internal.h"
+#include "lttng-tracer-core.h"
+#include "jhash.h"
+#include "context-provider-internal.h"
+#include "common/macros.h"
+
+struct lttng_ust_registered_context_provider {
+ const struct lttng_ust_context_provider *provider;
+
+ struct cds_hlist_node node;
+};
+
+struct lttng_ust_app_ctx {
+ char *name;
+ struct lttng_ust_event_field *event_field;
+ struct lttng_ust_type_common *type;
+};
+
+#define CONTEXT_PROVIDER_HT_BITS 12
+#define CONTEXT_PROVIDER_HT_SIZE (1U << CONTEXT_PROVIDER_HT_BITS)
+struct context_provider_ht {
+ struct cds_hlist_head table[CONTEXT_PROVIDER_HT_SIZE];
+};
+
+static struct context_provider_ht context_provider_ht;
+
+static const struct lttng_ust_context_provider *
+ lookup_provider_by_name(const char *name)
+{
+ struct cds_hlist_head *head;
+ struct cds_hlist_node *node;
+ struct lttng_ust_registered_context_provider *reg_provider;
+ uint32_t hash;
+ const char *end;
+ size_t len;
+
+ /* Lookup using everything before first ':' as key. */
+ end = strchr(name, ':');
+ if (end)
+ len = end - name;
+ else
+ len = strlen(name);
+ hash = jhash(name, len, 0);
+ head = &context_provider_ht.table[hash & (CONTEXT_PROVIDER_HT_SIZE - 1)];
+ cds_hlist_for_each_entry(reg_provider, node, head, node) {
+ if (!strncmp(reg_provider->provider->name, name, len))
+ return reg_provider->provider;
+ }
+ return NULL;
+}
+
+struct lttng_ust_registered_context_provider *lttng_ust_context_provider_register(struct lttng_ust_context_provider *provider)
+{
+ struct lttng_ust_registered_context_provider *reg_provider = NULL;
+ struct cds_hlist_head *head;
+ size_t name_len = strlen(provider->name);
+ uint32_t hash;
+
+ lttng_ust_fixup_tls();
+
+ /* Provider name starts with "$app.". */
+ if (strncmp("$app.", provider->name, strlen("$app.")) != 0)
+ return NULL;
+ /* Provider name cannot contain a colon character. */
+ if (strchr(provider->name, ':'))
+ return NULL;
+ if (ust_lock())
+ goto end;
+ if (lookup_provider_by_name(provider->name))
+ goto end;
+ reg_provider = zmalloc(sizeof(struct lttng_ust_registered_context_provider));
+ if (!reg_provider)
+ goto end;
+ reg_provider->provider = provider;
+ hash = jhash(provider->name, name_len, 0);
+ head = &context_provider_ht.table[hash & (CONTEXT_PROVIDER_HT_SIZE - 1)];
+ cds_hlist_add_head(®_provider->node, head);
+
+ lttng_ust_context_set_session_provider(provider->name,
+ provider->get_size, provider->record,
+ provider->get_value, provider->priv);
+
+ lttng_ust_context_set_event_notifier_group_provider(provider->name,
+ provider->get_size, provider->record,
+ provider->get_value, provider->priv);
+end:
+ ust_unlock();
+ return reg_provider;
+}
+
+void lttng_ust_context_provider_unregister(struct lttng_ust_registered_context_provider *reg_provider)
+{
+ lttng_ust_fixup_tls();
+
+ if (ust_lock())
+ goto end;
+ lttng_ust_context_set_session_provider(reg_provider->provider->name,
+ lttng_ust_dummy_get_size, lttng_ust_dummy_record,
+ lttng_ust_dummy_get_value, NULL);
+
+ lttng_ust_context_set_event_notifier_group_provider(reg_provider->provider->name,
+ lttng_ust_dummy_get_size, lttng_ust_dummy_record,
+ lttng_ust_dummy_get_value, NULL);
+
+ cds_hlist_del(®_provider->node);
+end:
+ ust_unlock();
+ free(reg_provider);
+}
+
+static void destroy_app_ctx(void *priv)
+{
+ struct lttng_ust_app_ctx *app_ctx = (struct lttng_ust_app_ctx *) priv;
+
+ free(app_ctx->name);
+ free(app_ctx->event_field);
+ free(app_ctx->type);
+ free(app_ctx);
+}
+
+/*
+ * Called with ust mutex held.
+ * Add application context to array of context, even if the application
+ * context is not currently loaded by application. It will then use the
+ * dummy callbacks in that case.
+ * Always performed before tracing is started, since it modifies
+ * metadata describing the context.
+ */
+int lttng_ust_add_app_context_to_ctx_rcu(const char *name,
+ struct lttng_ust_ctx **ctx)
+{
+ const struct lttng_ust_context_provider *provider;
+ struct lttng_ust_ctx_field new_field = { 0 };
+ struct lttng_ust_event_field *event_field = NULL;
+ struct lttng_ust_type_common *type = NULL;
+ struct lttng_ust_app_ctx *app_ctx = NULL;
+ char *ctx_name;
+ int ret;
+
+ if (*ctx && lttng_find_context(*ctx, name))
+ return -EEXIST;
+ event_field = zmalloc(sizeof(struct lttng_ust_event_field));
+ if (!event_field) {
+ ret = -ENOMEM;
+ goto error_event_field_alloc;
+ }
+ ctx_name = strdup(name);
+ if (!ctx_name) {
+ ret = -ENOMEM;
+ goto error_field_name_alloc;
+ }
+ type = zmalloc(sizeof(struct lttng_ust_type_common));
+ if (!type) {
+ ret = -ENOMEM;
+ goto error_field_type_alloc;
+ }
+ app_ctx = zmalloc(sizeof(struct lttng_ust_app_ctx));
+ if (!app_ctx) {
+ ret = -ENOMEM;
+ goto error_app_ctx_alloc;
+ }
+ event_field->name = ctx_name;
+ type->type = lttng_ust_type_dynamic;
+ event_field->type = type;
+ new_field.event_field = event_field;
+ /*
+ * If provider is not found, we add the context anyway, but
+ * it will provide a dummy context.
+ */
+ provider = lookup_provider_by_name(name);
+ if (provider) {
+ new_field.get_size = provider->get_size;
+ new_field.record = provider->record;
+ new_field.get_value = provider->get_value;
+ } else {
+ new_field.get_size = lttng_ust_dummy_get_size;
+ new_field.record = lttng_ust_dummy_record;
+ new_field.get_value = lttng_ust_dummy_get_value;
+ }
+ new_field.destroy = destroy_app_ctx;
+ new_field.priv = app_ctx;
+ /*
+ * For application context, add it by expanding
+ * ctx array.
+ */
+ ret = lttng_ust_context_append_rcu(ctx, &new_field);
+ if (ret) {
+ destroy_app_ctx(app_ctx);
+ return ret;
+ }
+ return 0;
+
+error_app_ctx_alloc:
+ free(type);
+error_field_type_alloc:
+ free(ctx_name);
+error_field_name_alloc:
+ free(event_field);
+error_event_field_alloc:
+ return ret;
+}
projects / lttng-ust.git / blobdiff