Refactoring: struct lttng_event_desc and lttng_probe_desc

- Properly namespace probe registration functions,
- Namespace those structures with lttng_ust_ prefix,
- Use struct_size extensibility scheme,
- Remove padding.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I316a4120d568b663381f4b9eae3e1405a83a1db5

diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
index d9e15d34a72f8a0cfedbac33344734dfe4da740b..b43b49e1a9f7ce7389f1f29aa6c28f8ab3e99db7 100644 (file)
--- a/include/lttng/ust-events.h
+++ b/include/lttng/ust-events.h
@@ -274,34 +274,51 @@ struct lttng_ctx {
        char padding[LTTNG_UST_CTX_PADDING];
 };
 
-#define LTTNG_UST_EVENT_DESC_PADDING   40
-struct lttng_event_desc {
+/*
+ * 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_event_desc {
+       uint32_t struct_size;                   /* Size of this structure. */
        const char *name;
        void (*probe_callback)(void);
        const struct lttng_event_ctx *ctx;      /* context */
        const struct lttng_event_field *fields; /* event payload */
        unsigned int nr_fields;
        const int **loglevel;
-       const char *signature;  /* Argument types/names received */
-       union {
-               struct {
-                       const char **model_emf_uri;
-               } ext;
-               char padding[LTTNG_UST_EVENT_DESC_PADDING];
-       } u;
+       const char *signature;                  /* Argument types/names received */
+       const char **model_emf_uri;
+
+       /* End of base ABI. Fields below should be used after checking struct_size. */
 };
 
-#define LTTNG_UST_PROBE_DESC_PADDING   12
-struct lttng_probe_desc {
+/*
+ * 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_probe_desc {
+       uint32_t struct_size;                   /* Size of this structure. */
+
        const char *provider;
-       const struct lttng_event_desc **event_desc;
+       const struct lttng_ust_event_desc **event_desc;
        unsigned int nr_events;
        struct cds_list_head head;              /* chain registered probes */
        struct cds_list_head lazy_init_head;
        int lazy;                               /* lazy registration */
        uint32_t major;
        uint32_t minor;
-       char padding[LTTNG_UST_PROBE_DESC_PADDING];
+
+       /* End of base ABI. Fields below should be used after checking struct_size. */
 };
 
 /* Data structures used by the tracer. */
@@ -586,8 +603,8 @@ struct lttng_session {
        /* End of base ABI. Fields below should be used after checking struct_size. */
 };
 
-int lttng_probe_register(struct lttng_probe_desc *desc);
-void lttng_probe_unregister(struct lttng_probe_desc *desc);
+int lttng_ust_probe_register(struct lttng_ust_probe_desc *desc);
+void lttng_ust_probe_unregister(struct lttng_ust_probe_desc *desc);
 
 /*
  * Can be used by applications that change their procname to clear the ust cached value.

diff --git a/include/lttng/ust-tracepoint-event.h b/include/lttng/ust-tracepoint-event.h
index 5b3d9a1b9773b88a19e89cc64ec11ba6c8525408..9fbe70e8d4f119e69ce22b9af7587c073e9f05ba 100644 (file)
--- a/include/lttng/ust-tracepoint-event.h
+++ b/include/lttng/ust-tracepoint-event.h
@@ -1020,19 +1020,16 @@ static const int *                                                             \
 static const char *                                                           \
        __ref_model_emf_uri___##_provider##___##_name                          \
        __attribute__((weakref ("_model_emf_uri___" #_provider "___" #_name)));\
-static const struct lttng_event_desc __event_desc___##_provider##_##_name = {         \
+static const struct lttng_ust_event_desc __event_desc___##_provider##_##_name = { \
+       .struct_size = sizeof(struct lttng_ust_event_desc),                    \
        .name = #_provider ":" #_name,                                         \
-       .probe_callback = (void (*)(void)) &__event_probe__##_provider##___##_template,\
+       .probe_callback = (void (*)(void)) &__event_probe__##_provider##___##_template, \
        .ctx = NULL,                                                           \
        .fields = __event_fields___##_provider##___##_template,                \
        .nr_fields = _TP_ARRAY_SIZE(__event_fields___##_provider##___##_template) - 1, \
        .loglevel = &__ref_loglevel___##_provider##___##_name,                 \
        .signature = __tp_event_signature___##_provider##___##_template,       \
-       .u = {                                                                 \
-           .ext = {                                                           \
-                 .model_emf_uri = &__ref_model_emf_uri___##_provider##___##_name, \
-               },                                                             \
-       },                                                                     \
+       .model_emf_uri = &__ref_model_emf_uri___##_provider##___##_name,       \
 };
 
 #include TRACEPOINT_INCLUDE
@@ -1050,7 +1047,7 @@ static const struct lttng_event_desc __event_desc___##_provider##_##_name = {
 #define _TRACEPOINT_EVENT_INSTANCE(_provider, _template, _name, _args)        \
        &__event_desc___##_provider##_##_name,
 
-static const struct lttng_event_desc *_TP_COMBINE_TOKENS(__event_desc___, TRACEPOINT_PROVIDER)[] = {
+static const struct lttng_ust_event_desc *_TP_COMBINE_TOKENS(__event_desc___, TRACEPOINT_PROVIDER)[] = {
 #include TRACEPOINT_INCLUDE
        NULL,   /* Dummy, C99 forbids 0-len array. */
 };
@@ -1063,7 +1060,8 @@ static const struct lttng_event_desc *_TP_COMBINE_TOKENS(__event_desc___, TRACEP
  */
 
 /* non-const because list head will be modified when registered. */
-static struct lttng_probe_desc _TP_COMBINE_TOKENS(__probe_desc___, TRACEPOINT_PROVIDER) = {
+static struct lttng_ust_probe_desc _TP_COMBINE_TOKENS(__probe_desc___, TRACEPOINT_PROVIDER) = {
+       .struct_size = sizeof(struct lttng_ust_probe_desc),
        .provider = __tp_stringify(TRACEPOINT_PROVIDER),
        .event_desc = _TP_COMBINE_TOKENS(__event_desc___, TRACEPOINT_PROVIDER),
        .nr_events = _TP_ARRAY_SIZE(_TP_COMBINE_TOKENS(__event_desc___, TRACEPOINT_PROVIDER)) - 1,
@@ -1109,7 +1107,7 @@ _TP_COMBINE_TOKENS(__lttng_events_init__, TRACEPOINT_PROVIDER)(void)
         * error will appear.
         */
        _TP_COMBINE_TOKENS(__tracepoint_provider_check_, TRACEPOINT_PROVIDER)();
-       ret = lttng_probe_register(&_TP_COMBINE_TOKENS(__probe_desc___, TRACEPOINT_PROVIDER));
+       ret = lttng_ust_probe_register(&_TP_COMBINE_TOKENS(__probe_desc___, TRACEPOINT_PROVIDER));
        if (ret) {
                fprintf(stderr, "LTTng-UST: Error (%d) while registering tracepoint probe.\n", ret);
                abort();
@@ -1125,7 +1123,7 @@ _TP_COMBINE_TOKENS(__lttng_events_exit__, TRACEPOINT_PROVIDER)(void)
                        TRACEPOINT_PROVIDER)) {
                return;
        }
-       lttng_probe_unregister(&_TP_COMBINE_TOKENS(__probe_desc___, TRACEPOINT_PROVIDER));
+       lttng_ust_probe_unregister(&_TP_COMBINE_TOKENS(__probe_desc___, TRACEPOINT_PROVIDER));
 }
 
 int _TP_COMBINE_TOKENS(__tracepoint_provider_, TRACEPOINT_PROVIDER)

diff --git a/liblttng-ust/lttng-bytecode-specialize.c b/liblttng-ust/lttng-bytecode-specialize.c
index f571dd60197b08b38f247f288ebd38d8e4063703..2982a7930ccdc9cb0e215c1c7e32d0d975a7219e 100644 (file)
--- a/liblttng-ust/lttng-bytecode-specialize.c
+++ b/liblttng-ust/lttng-bytecode-specialize.c
@@ -546,7 +546,7 @@ end:
        return ret;
 }
 
-static int specialize_payload_lookup(const struct lttng_event_desc *event_desc,
+static int specialize_payload_lookup(const struct lttng_ust_event_desc *event_desc,
                struct bytecode_runtime *runtime,
                struct load_op *insn,
                struct vstack_load *load)
@@ -623,7 +623,7 @@ end:
        return ret;
 }
 
-int lttng_bytecode_specialize(const struct lttng_event_desc *event_desc,
+int lttng_bytecode_specialize(const struct lttng_ust_event_desc *event_desc,
                struct bytecode_runtime *bytecode)
 {
        void *pc, *next_pc, *start_pc;

diff --git a/liblttng-ust/lttng-bytecode.c b/liblttng-ust/lttng-bytecode.c
index 94edbab63312cf1a4bc954b4f06f35fb5b64144d..ef458055f14f7eec51f2a74c1acf9c8e107ebf60 100644 (file)
--- a/liblttng-ust/lttng-bytecode.c
+++ b/liblttng-ust/lttng-bytecode.c
@@ -171,7 +171,7 @@ const char *lttng_bytecode_print_op(enum bytecode_op op)
 }
 
 static
-int apply_field_reloc(const struct lttng_event_desc *event_desc,
+int apply_field_reloc(const struct lttng_ust_event_desc *event_desc,
                struct bytecode_runtime *runtime,
                uint32_t runtime_len,
                uint32_t reloc_offset,
@@ -341,7 +341,7 @@ int apply_context_reloc(struct bytecode_runtime *runtime,
 }
 
 static
-int apply_reloc(const struct lttng_event_desc *event_desc,
+int apply_reloc(const struct lttng_ust_event_desc *event_desc,
                struct bytecode_runtime *runtime,
                uint32_t runtime_len,
                uint32_t reloc_offset,
@@ -395,7 +395,7 @@ int bytecode_is_linked(struct lttng_ust_bytecode_node *bytecode,
  * bytecode runtime.
  */
 static
-int link_bytecode(const struct lttng_event_desc *event_desc,
+int link_bytecode(const struct lttng_ust_event_desc *event_desc,
                struct lttng_ctx **ctx,
                struct lttng_ust_bytecode_node *bytecode,
                struct cds_list_head *bytecode_runtime_head,
@@ -527,7 +527,7 @@ void lttng_bytecode_capture_sync_state(struct lttng_bytecode_runtime *runtime)
  * This function is called after we confirmed that name enabler and the
  * instance are name matching (or glob pattern matching).
  */
-void lttng_enabler_link_bytecode(const struct lttng_event_desc *event_desc,
+void lttng_enabler_link_bytecode(const struct lttng_ust_event_desc *event_desc,
                struct lttng_ctx **ctx,
                struct cds_list_head *instance_bytecode_head,
                struct cds_list_head *enabler_bytecode_head)

diff --git a/liblttng-ust/lttng-bytecode.h b/liblttng-ust/lttng-bytecode.h
index 4e9f97c99468d3b4286c92f2b862b744fb14208d..8caf15ecd43d2eb1e2c7d470e49029b6b9f45fba 100644 (file)
--- a/liblttng-ust/lttng-bytecode.h
+++ b/liblttng-ust/lttng-bytecode.h
@@ -325,7 +325,7 @@ void lttng_bytecode_capture_sync_state(struct lttng_bytecode_runtime *runtime);
 LTTNG_HIDDEN
 int lttng_bytecode_validate(struct bytecode_runtime *bytecode);
 LTTNG_HIDDEN
-int lttng_bytecode_specialize(const struct lttng_event_desc *event_desc,
+int lttng_bytecode_specialize(const struct lttng_ust_event_desc *event_desc,
                struct bytecode_runtime *bytecode);
 
 LTTNG_HIDDEN

diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c
index 5a3aae8d8725191c34398a1d89305efc735a8865..7dfe6b7a6d46a5a6fa62eaffa5f72a8f37aae665 100644 (file)
--- a/liblttng-ust/lttng-events.c
+++ b/liblttng-ust/lttng-events.c
@@ -250,7 +250,7 @@ static
 void register_event(struct lttng_ust_event_common *event)
 {
        int ret;
-       const struct lttng_event_desc *desc;
+       const struct lttng_ust_event_desc *desc;
 
        assert(event->priv->registered == 0);
        desc = event->priv->desc;
@@ -266,7 +266,7 @@ static
 void unregister_event(struct lttng_ust_event_common *event)
 {
        int ret;
-       const struct lttng_event_desc *desc;
+       const struct lttng_ust_event_desc *desc;
 
        assert(event->priv->registered == 1);
        desc = event->priv->desc;
@@ -675,7 +675,7 @@ static inline
 struct cds_hlist_head *borrow_hash_table_bucket(
                struct cds_hlist_head *hash_table,
                unsigned int hash_table_size,
-               const struct lttng_event_desc *desc)
+               const struct lttng_ust_event_desc *desc)
 {
        const char *event_name;
        size_t name_len;
@@ -692,7 +692,7 @@ struct cds_hlist_head *borrow_hash_table_bucket(
  * Supports event creation while tracing session is active.
  */
 static
-int lttng_event_recorder_create(const struct lttng_event_desc *desc,
+int lttng_event_recorder_create(const struct lttng_ust_event_desc *desc,
                struct lttng_channel *chan)
 {
        struct lttng_ust_event_recorder *event_recorder;
@@ -761,8 +761,8 @@ int lttng_event_recorder_create(const struct lttng_event_desc *desc,
                loglevel = *(*event_recorder->parent->priv->desc->loglevel);
        else
                loglevel = TRACE_DEFAULT;
-       if (desc->u.ext.model_emf_uri)
-               uri = *(desc->u.ext.model_emf_uri);
+       if (desc->model_emf_uri)
+               uri = *(desc->model_emf_uri);
        else
                uri = NULL;
 
@@ -800,7 +800,7 @@ socket_error:
 }
 
 static
-int lttng_event_notifier_create(const struct lttng_event_desc *desc,
+int lttng_event_notifier_create(const struct lttng_ust_event_desc *desc,
                uint64_t token, uint64_t error_counter_index,
                struct lttng_event_notifier_group *event_notifier_group)
 {
@@ -872,7 +872,7 @@ error:
 }
 
 static
-int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
+int lttng_desc_match_star_glob_enabler(const struct lttng_ust_event_desc *desc,
                struct lttng_enabler *enabler)
 {
        int loglevel = 0;
@@ -895,7 +895,7 @@ int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 }
 
 static
-int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
+int lttng_desc_match_event_enabler(const struct lttng_ust_event_desc *desc,
                struct lttng_enabler *enabler)
 {
        int loglevel = 0;
@@ -917,7 +917,7 @@ int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 }
 
 static
-int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
+int lttng_desc_match_enabler(const struct lttng_ust_event_desc *desc,
                struct lttng_enabler *enabler)
 {
        switch (enabler->format_type) {
@@ -1005,8 +1005,8 @@ static
 void lttng_create_event_recorder_if_missing(struct lttng_event_enabler *event_enabler)
 {
        struct lttng_session *session = event_enabler->chan->session;
-       struct lttng_probe_desc *probe_desc;
-       const struct lttng_event_desc *desc;
+       struct lttng_ust_probe_desc *probe_desc;
+       const struct lttng_ust_event_desc *desc;
        struct lttng_ust_event_recorder_private *event_recorder_priv;
        int i;
        struct cds_list_head *probe_list;
@@ -1058,7 +1058,7 @@ void lttng_create_event_recorder_if_missing(struct lttng_event_enabler *event_en
 }
 
 static
-void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
+void probe_provider_event_for_each(struct lttng_ust_probe_desc *provider_desc,
                void (*event_func)(struct lttng_ust_event_common *event))
 {
        struct cds_hlist_node *node, *tmp_node;
@@ -1073,7 +1073,7 @@ void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
         * sessions to queue the unregistration of the events.
         */
        for (i = 0; i < provider_desc->nr_events; i++) {
-               const struct lttng_event_desc *event_desc;
+               const struct lttng_ust_event_desc *event_desc;
                struct lttng_event_notifier_group *event_notifier_group;
                struct lttng_ust_event_recorder_private *event_recorder_priv;
                struct lttng_ust_event_notifier_private *event_notifier_priv;
@@ -1175,7 +1175,7 @@ void _event_enum_destroy(struct lttng_ust_event_common *event)
  * ust_lock held.
  */
 void lttng_probe_provider_unregister_events(
-               struct lttng_probe_desc *provider_desc)
+               struct lttng_ust_probe_desc *provider_desc)
 {
        /*
         * Iterate over all events in the probe provider descriptions and sessions
@@ -1708,7 +1708,7 @@ void lttng_session_sync_event_enablers(struct lttng_session *session)
 
 /* Support for event notifier is introduced by probe provider major version 2. */
 static
-bool lttng_ust_probe_supports_event_notifier(struct lttng_probe_desc *probe_desc)
+bool lttng_ust_probe_supports_event_notifier(struct lttng_ust_probe_desc *probe_desc)
 {
        return probe_desc->major >= 2;
 }
@@ -1718,7 +1718,7 @@ void lttng_create_event_notifier_if_missing(
                struct lttng_event_notifier_enabler *event_notifier_enabler)
 {
        struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
-       struct lttng_probe_desc *probe_desc;
+       struct lttng_ust_probe_desc *probe_desc;
        struct cds_list_head *probe_list;
        int i;
 
@@ -1728,7 +1728,7 @@ void lttng_create_event_notifier_if_missing(
                for (i = 0; i < probe_desc->nr_events; i++) {
                        int ret;
                        bool found = false;
-                       const struct lttng_event_desc *desc;
+                       const struct lttng_ust_event_desc *desc;
                        struct lttng_ust_event_notifier_private *event_notifier_priv;
                        struct cds_hlist_head *head;
                        struct cds_hlist_node *node;

diff --git a/liblttng-ust/lttng-probes.c b/liblttng-ust/lttng-probes.c
index 3d3e60e7193369fb0a1562e8dee21be33c269d91..d009a87461108661f01dfca78021095f0eb4baed 100644 (file)
--- a/liblttng-ust/lttng-probes.c
+++ b/liblttng-ust/lttng-probes.c
@@ -44,7 +44,7 @@ static int lazy_nesting;
  * Called under ust lock.
  */
 static
-int check_event_provider(struct lttng_probe_desc *desc)
+int check_event_provider(struct lttng_ust_probe_desc *desc)
 {
        int i;
        size_t provider_name_len;
@@ -64,9 +64,9 @@ int check_event_provider(struct lttng_probe_desc *desc)
  * Called under ust lock.
  */
 static
-void lttng_lazy_probe_register(struct lttng_probe_desc *desc)
+void lttng_lazy_probe_register(struct lttng_ust_probe_desc *desc)
 {
-       struct lttng_probe_desc *iter;
+       struct lttng_ust_probe_desc *iter;
        struct cds_list_head *probe_list;
 
        /*
@@ -84,7 +84,7 @@ void lttng_lazy_probe_register(struct lttng_probe_desc *desc)
         */
 
        /*
-        * We sort the providers by struct lttng_probe_desc pointer
+        * We sort the providers by struct lttng_ust_probe_desc pointer
         * address.
         */
        probe_list = &_probe_list;
@@ -109,7 +109,7 @@ desc_added:
 static
 void fixup_lazy_probes(void)
 {
-       struct lttng_probe_desc *iter, *tmp;
+       struct lttng_ust_probe_desc *iter, *tmp;
        int ret;
 
        lazy_nesting++;
@@ -135,7 +135,7 @@ struct cds_list_head *lttng_get_probe_list_head(void)
 }
 
 static
-int check_provider_version(struct lttng_probe_desc *desc)
+int check_provider_version(struct lttng_ust_probe_desc *desc)
 {
        /*
         * Check tracepoint provider version compatibility.
@@ -164,7 +164,7 @@ int check_provider_version(struct lttng_probe_desc *desc)
 }
 
 
-int lttng_probe_register(struct lttng_probe_desc *desc)
+int lttng_ust_probe_register(struct lttng_ust_probe_desc *desc)
 {
        int ret = 0;
 
@@ -197,7 +197,7 @@ int lttng_probe_register(struct lttng_probe_desc *desc)
        return ret;
 }
 
-void lttng_probe_unregister(struct lttng_probe_desc *desc)
+void lttng_ust_probe_unregister(struct lttng_ust_probe_desc *desc)
 {
        lttng_ust_fixup_tls();
 
@@ -231,7 +231,7 @@ void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
  */
 int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
 {
-       struct lttng_probe_desc *probe_desc;
+       struct lttng_ust_probe_desc *probe_desc;
        int i;
        struct cds_list_head *probe_list;
 
@@ -303,7 +303,7 @@ void lttng_probes_prune_field_list(struct lttng_ust_field_list *list)
  */
 int lttng_probes_get_field_list(struct lttng_ust_field_list *list)
 {
-       struct lttng_probe_desc *probe_desc;
+       struct lttng_ust_probe_desc *probe_desc;
        int i;
        struct cds_list_head *probe_list;
 
@@ -311,7 +311,7 @@ int lttng_probes_get_field_list(struct lttng_ust_field_list *list)
        CDS_INIT_LIST_HEAD(&list->head);
        cds_list_for_each_entry(probe_desc, probe_list, head) {
                for (i = 0; i < probe_desc->nr_events; i++) {
-                       const struct lttng_event_desc *event_desc =
+                       const struct lttng_ust_event_desc *event_desc =
                                probe_desc->event_desc[i];
                        int j;
 

diff --git a/liblttng-ust/ust-events-internal.h b/liblttng-ust/ust-events-internal.h
index 0cec28704e2bb5d949e3ac4ec0957d8bc0d548f2..ac85b7116e2931fdfd6430a7403a814461fa43ce 100644 (file)
--- a/liblttng-ust/ust-events-internal.h
+++ b/liblttng-ust/ust-events-internal.h
@@ -203,7 +203,7 @@ struct lttng_counter_transport {
 struct lttng_ust_event_common_private {
        struct lttng_ust_event_common *pub;     /* Public event interface */
 
-       const struct lttng_event_desc *desc;
+       const struct lttng_ust_event_desc *desc;
        /* Backward references: list of lttng_enabler_ref (ref to enablers) */
        struct cds_list_head enablers_ref_head;
        int registered;                 /* has reg'd tracepoint probe */
@@ -346,7 +346,7 @@ int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *enabler,
  * event_notifier enabler) to ensure each is linked to the provided instance.
  */
 LTTNG_HIDDEN
-void lttng_enabler_link_bytecode(const struct lttng_event_desc *event_desc,
+void lttng_enabler_link_bytecode(const struct lttng_ust_event_desc *event_desc,
                struct lttng_ctx **ctx,
                struct cds_list_head *instance_bytecode_runtime_head,
                struct cds_list_head *enabler_bytecode_runtime_head);
@@ -533,7 +533,7 @@ LTTNG_HIDDEN
 void lttng_transport_unregister(struct lttng_transport *transport);
 
 LTTNG_HIDDEN
-void lttng_probe_provider_unregister_events(struct lttng_probe_desc *desc);
+void lttng_probe_provider_unregister_events(struct lttng_ust_probe_desc *desc);
 
 LTTNG_HIDDEN
 int lttng_fix_pending_events(void);