Fix: Java application context: pass application context argument to callbacks

The callbacks require the complete application context field names to
compare against the tables received from the TLS area.

We also need to free memory allocated by for the context event field and
context name in a destroy callback.

Therefore, allocate a data structure for each application context, and
use that data structure as private data. This allows callback to reach
the context name, and a destroy callback to free the allocated memory.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ia34fe00f5945fb58ef991f9d40dec36ac9ab322c

diff --git a/src/common/ust-context-provider.h b/src/common/ust-context-provider.h
index d8c9a138c7d8f05e48a8b7dedc3fde565f2e4fa4..43e75b4bcdaa448812dfb2c3e6790aaaba12aea1 100644 (file)
--- a/src/common/ust-context-provider.h
+++ b/src/common/ust-context-provider.h
@@ -67,6 +67,27 @@ struct lttng_ust_context_provider {
        /* End of base ABI. Fields below should be used after checking struct_size. */
 };
 
+/*
+ * Application context callback private data
+ *
+ * IMPORTANT: this structure is part of the ABI between the probe and
+ * UST. Fields need to be only added at the end, never reordered, never
+ * removed.
+ *
+ * The field @struct_size should be used to determine the size of the
+ * structure. It should be queried before using additional fields added
+ * at the end of the structure.
+ */
+
+struct lttng_ust_app_context {
+       uint32_t struct_size;
+
+       struct lttng_ust_event_field *event_field;
+       char *ctx_name;
+
+       /* End of base ABI. Fields below should be used after checking struct_size. */
+};
+
 /*
  * Returns an opaque pointer on success, which must be passed to
  * lttng_ust_context_provider_unregister for unregistration. Returns

diff --git a/src/lib/lttng-ust-java-agent/jni/common/lttng_ust_context.c b/src/lib/lttng-ust-java-agent/jni/common/lttng_ust_context.c
index 4f4fa9b77d4cd671c85ef759eb713b103c675667..5e6add28704a8993759784d9e7268a24fea16aa8 100644 (file)
--- a/src/lib/lttng-ust-java-agent/jni/common/lttng_ust_context.c
+++ b/src/lib/lttng-ust-java-agent/jni/common/lttng_ust_context.c
@@ -82,10 +82,10 @@ static struct lttng_ust_jni_ctx_entry *lookup_ctx_by_name(const char *ctx_name)
 static size_t get_size_cb(void *priv, struct lttng_ust_probe_ctx *probe_ctx __attribute__((unused)),
                size_t offset)
 {
+       const struct lttng_ust_app_context *app_ctx = (const struct lttng_ust_app_context *) priv;
+       const char *ctx_name = app_ctx->ctx_name;
        struct lttng_ust_jni_ctx_entry *jctx;
        size_t size = 0;
-       struct lttng_ust_jni_provider *jni_provider = (struct lttng_ust_jni_provider *) priv;
-       const char *ctx_name = jni_provider->name;
        enum lttng_ust_jni_type jni_type;
 
        size += lttng_ust_ring_buffer_align(offset, lttng_ust_rb_alignof(char));
@@ -147,9 +147,9 @@ static void record_cb(void *priv,
                 struct lttng_ust_ring_buffer_ctx *ctx,
                 struct lttng_ust_channel_buffer *lttng_chan_buf)
 {
+       const struct lttng_ust_app_context *app_ctx = (const struct lttng_ust_app_context *) priv;
+       const char *ctx_name = app_ctx->ctx_name;
        struct lttng_ust_jni_ctx_entry *jctx;
-       struct lttng_ust_jni_provider *jni_provider = (struct lttng_ust_jni_provider *) priv;
-       const char *ctx_name = jni_provider->name;
        enum lttng_ust_jni_type jni_type;
        char sel_char;
 
@@ -252,9 +252,9 @@ static void record_cb(void *priv,
 static void get_value_cb(void *priv, struct lttng_ust_probe_ctx *probe_ctx __attribute__((unused)),
                struct lttng_ust_ctx_value *value)
 {
-       struct lttng_ust_jni_provider *jni_provider = (struct lttng_ust_jni_provider *) priv;
+       const struct lttng_ust_app_context *app_ctx = (const struct lttng_ust_app_context *) priv;
+       const char *ctx_name = app_ctx->ctx_name;
        struct lttng_ust_jni_ctx_entry *jctx;
-       const char *ctx_name = jni_provider->name;
        enum lttng_ust_jni_type jni_type;
 
        jctx = lookup_ctx_by_name(ctx_name);

diff --git a/src/lib/lttng-ust/context-provider-internal.h b/src/lib/lttng-ust/context-provider-internal.h
index 92de7dffd82f39d48543f4e36ac1d628dab66210..cf1a1306dc78443e542899573fb62b91ccb95fed 100644 (file)
--- a/src/lib/lttng-ust/context-provider-internal.h
+++ b/src/lib/lttng-ust/context-provider-internal.h
@@ -17,8 +17,7 @@ void lttng_ust_context_set_event_notifier_group_provider(const char *name,
                        struct lttng_ust_ring_buffer_ctx *ctx,
                        struct lttng_ust_channel_buffer *chan),
                void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
-                       struct lttng_ust_ctx_value *value),
-               void *priv)
+                       struct lttng_ust_ctx_value *value))
        __attribute__((visibility("hidden")));
 
 #endif /* _LTTNG_UST_CONTEXT_PROVIDER_INTERNAL_H */

diff --git a/src/lib/lttng-ust/events.h b/src/lib/lttng-ust/events.h
index 3ef0dbcb370fa42a83c7c0aaf54e2571e9056c12..cfdbd2e0c7913e6d64ce9aaa9cdda7fd3d0dddbf 100644 (file)
--- a/src/lib/lttng-ust/events.h
+++ b/src/lib/lttng-ust/events.h
@@ -316,8 +316,7 @@ int lttng_ust_context_set_provider_rcu(struct lttng_ust_ctx **_ctx,
                        struct lttng_ust_ring_buffer_ctx *ctx,
                        struct lttng_ust_channel_buffer *chan),
                void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
-                       struct lttng_ust_ctx_value *value),
-               void *priv)
+                       struct lttng_ust_ctx_value *value))
        __attribute__((visibility("hidden")));
 
 void lttng_ust_context_set_session_provider(const char *name,
@@ -327,8 +326,7 @@ void lttng_ust_context_set_session_provider(const char *name,
                        struct lttng_ust_ring_buffer_ctx *ctx,
                        struct lttng_ust_channel_buffer *chan),
                void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
-                       struct lttng_ust_ctx_value *value),
-               void *priv)
+                       struct lttng_ust_ctx_value *value))
        __attribute__((visibility("hidden")));
 
 #endif /* _LTTNG_UST_EVENTS_INTERNAL_H */

diff --git a/src/lib/lttng-ust/lttng-context-provider.c b/src/lib/lttng-ust/lttng-context-provider.c
index b411812205e4fa0e980275adda600441fcffe5e0..4e7e429fcc6ee662c744cd94a818eca68d01eb5f 100644 (file)
--- a/src/lib/lttng-ust/lttng-context-provider.c
+++ b/src/lib/lttng-ust/lttng-context-provider.c
@@ -89,11 +89,11 @@ struct lttng_ust_registered_context_provider *lttng_ust_context_provider_registe
 
        lttng_ust_context_set_session_provider(provider->name,
                provider->get_size, provider->record,
-               provider->get_value, provider->priv);
+               provider->get_value);
 
        lttng_ust_context_set_event_notifier_group_provider(provider->name,
                provider->get_size, provider->record,
-               provider->get_value, provider->priv);
+               provider->get_value);
 end:
        ust_unlock();
        return reg_provider;
@@ -107,11 +107,11 @@ void lttng_ust_context_provider_unregister(struct lttng_ust_registered_context_p
                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_dummy_get_value);
 
        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);
+               lttng_ust_dummy_get_value);
 
        cds_hlist_del(&reg_provider->node);
 end:
@@ -119,6 +119,20 @@ end:
        free(reg_provider);
 }
 
+static
+void app_context_destroy(void *priv)
+{
+       struct lttng_ust_app_context *app_ctx = (struct lttng_ust_app_context *) priv;
+
+       free(app_ctx->ctx_name);
+       free(app_ctx->event_field);
+}
+
+static
+const struct lttng_ust_type_common app_ctx_type = {
+       .type = lttng_ust_type_dynamic,
+};
+
 /*
  * Called with ust mutex held.
  * Add application context to array of context, even if the application
@@ -133,7 +147,7 @@ int lttng_ust_add_app_context_to_ctx_rcu(const char *name,
        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_context *app_ctx = NULL;
        char *ctx_name;
        int ret;
 
@@ -149,14 +163,17 @@ int lttng_ust_add_app_context_to_ctx_rcu(const char *name,
                ret = -ENOMEM;
                goto error_field_name_alloc;
        }
-       type = zmalloc(sizeof(struct lttng_ust_type_common));
-       if (!type) {
+       app_ctx = zmalloc(sizeof(struct lttng_ust_app_context));
+       if (!app_ctx) {
                ret = -ENOMEM;
-               goto error_field_type_alloc;
+               goto error_app_ctx_alloc;
        }
+       app_ctx->struct_size = sizeof(struct lttng_ust_app_context);
+       app_ctx->event_field = event_field;
+       app_ctx->ctx_name = ctx_name;
+
        event_field->name = ctx_name;
-       type->type = lttng_ust_type_dynamic;
-       event_field->type = type;
+       event_field->type = &app_ctx_type;
        new_field.event_field = event_field;
        /*
         * If provider is not found, we add the context anyway, but
@@ -167,13 +184,13 @@ int lttng_ust_add_app_context_to_ctx_rcu(const char *name,
                new_field.get_size = provider->get_size;
                new_field.record = provider->record;
                new_field.get_value = provider->get_value;
-               new_field.priv = provider->priv;
        } 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.priv = NULL;
        }
+       new_field.priv = app_ctx;
+       new_field.destroy = app_context_destroy;
        /*
         * For application context, add it by expanding
         * ctx array.
@@ -185,8 +202,8 @@ int lttng_ust_add_app_context_to_ctx_rcu(const char *name,
        return 0;
 
 error_append:
-       free(type);
-error_field_type_alloc:
+       free(app_ctx);
+error_app_ctx_alloc:
        free(ctx_name);
 error_field_name_alloc:
        free(event_field);

diff --git a/src/lib/lttng-ust/lttng-context.c b/src/lib/lttng-ust/lttng-context.c
index 427afe56d78d86ece23454e71dc7b5de248484f2..fa209a2cbcc013786fa3eeb212ba4560ee1ffb58 100644 (file)
--- a/src/lib/lttng-ust/lttng-context.c
+++ b/src/lib/lttng-ust/lttng-context.c
@@ -260,8 +260,7 @@ int lttng_ust_context_set_provider_rcu(struct lttng_ust_ctx **_ctx,
                        struct lttng_ust_ring_buffer_ctx *ctx,
                        struct lttng_ust_channel_buffer *chan),
                void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
-                       struct lttng_ust_ctx_value *value),
-               void *priv)
+                       struct lttng_ust_ctx_value *value))
 {
        int i, ret;
        struct lttng_ust_ctx *ctx = *_ctx, *new_ctx;
@@ -291,7 +290,6 @@ int lttng_ust_context_set_provider_rcu(struct lttng_ust_ctx **_ctx,
                new_fields[i].get_size = get_size;
                new_fields[i].record = record;
                new_fields[i].get_value = get_value;
-               new_fields[i].priv = priv;
        }
        new_ctx->fields = new_fields;
        lttng_ust_rcu_assign_pointer(*_ctx, new_ctx);

diff --git a/src/lib/lttng-ust/lttng-events.c b/src/lib/lttng-ust/lttng-events.c
index 2607159447da667f7cf52cad8c83cf00c0d150ef..f8170f556210dba2900f8ae4f761dce118b362e3 100644 (file)
--- a/src/lib/lttng-ust/lttng-events.c
+++ b/src/lib/lttng-ust/lttng-events.c
@@ -2002,8 +2002,7 @@ void lttng_ust_context_set_session_provider(const char *name,
                        struct lttng_ust_ring_buffer_ctx *ctx,
                        struct lttng_ust_channel_buffer *chan),
                void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
-                       struct lttng_ust_ctx_value *value),
-               void *priv)
+                       struct lttng_ust_ctx_value *value))
 {
        struct lttng_ust_session_private *session_priv;
 
@@ -2013,18 +2012,18 @@ void lttng_ust_context_set_session_provider(const char *name,
                int ret;
 
                ret = lttng_ust_context_set_provider_rcu(&session_priv->ctx,
-                               name, get_size, record, get_value, priv);
+                               name, get_size, record, get_value);
                if (ret)
                        abort();
                cds_list_for_each_entry(chan, &session_priv->chan_head, node) {
                        ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
-                                       name, get_size, record, get_value, priv);
+                                       name, get_size, record, get_value);
                        if (ret)
                                abort();
                }
                cds_list_for_each_entry(event_recorder_priv, &session_priv->events_head, node) {
                        ret = lttng_ust_context_set_provider_rcu(&event_recorder_priv->ctx,
-                                       name, get_size, record, get_value, priv);
+                                       name, get_size, record, get_value);
                        if (ret)
                                abort();
                }
@@ -2045,8 +2044,7 @@ void lttng_ust_context_set_event_notifier_group_provider(const char *name,
                        struct lttng_ust_ring_buffer_ctx *ctx,
                        struct lttng_ust_channel_buffer *chan),
                void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
-                       struct lttng_ust_ctx_value *value),
-               void *priv)
+                       struct lttng_ust_ctx_value *value))
 {
        struct lttng_event_notifier_group *event_notifier_group;
 
@@ -2055,7 +2053,7 @@ void lttng_ust_context_set_event_notifier_group_provider(const char *name,
 
                ret = lttng_ust_context_set_provider_rcu(
                                &event_notifier_group->ctx,
-                               name, get_size, record, get_value, priv);
+                               name, get_size, record, get_value);
                if (ret)
                        abort();
        }