Introduce LTTNG_UST_MAP_POPULATE_POLICY environment variable
[lttng-ust.git] / include / lttng / tracepoint.h
index 5863e8457d44f0356e83eaf0cbd43d80eb96dd28..9342c5c1f5a09e1c2db375b285f4679c5e81c22a 100644 (file)
@@ -1,26 +1,33 @@
-/*
- * SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- */
+// SPDX-FileCopyrightText: 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+//
+// SPDX-License-Identifier: MIT
 
-#ifndef _LTTNG_TRACEPOINT_H
-#define _LTTNG_TRACEPOINT_H
+#ifndef _LTTNG_UST_TRACEPOINT_H
+#define _LTTNG_UST_TRACEPOINT_H
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <lttng/tracepoint-types.h>
 #include <lttng/tracepoint-rcu.h>
+#include <lttng/ust-utils.h>
+#include <sys/types.h>
+#include <unistd.h>
+
 #include <urcu/compiler.h>
 #include <urcu/system.h>
 #include <dlfcn.h>     /* for dlopen */
 #include <string.h>    /* for memset */
+#include <stdbool.h>
 
 #include <lttng/ust-config.h>  /* for sdt */
 #include <lttng/ust-compiler.h>
 #include <lttng/ust-tracer.h>
 #include <lttng/ust-api-compat.h>
 
+#if (defined(__cplusplus) && (__cplusplus <= 199711L))
+#error "C++11 support is required to build tracepoints and providers as C++"
+#endif
+
 #define LTTNG_UST_TRACEPOINT_NAME_LEN_MAX      256
 
 #ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
@@ -182,7 +189,8 @@ extern "C" {
  * address.
  */
 #define LTTNG_UST__DECLARE_TRACEPOINT(_provider, _name, ...)                                   \
-extern struct lttng_ust_tracepoint lttng_ust_tracepoint_##_provider##___##_name;               \
+extern struct lttng_ust_tracepoint lttng_ust_tracepoint_##_provider##___##_name                \
+               LTTNG_UST__TRACEPOINT_DEFINITION_VISIBILITY;                            \
 static inline                                                                          \
 void lttng_ust_tracepoint_cb_##_provider##___##_name(LTTNG_UST__TP_ARGS_PROTO(__VA_ARGS__))            \
        __attribute__((always_inline, unused)) lttng_ust_notrace;                       \
@@ -215,7 +223,7 @@ static inline                                                                               \
 void lttng_ust_tracepoint_register_##_provider##___##_name(char *provider_name, char *event_name, \
                void (*func)(void), void *data)                                         \
 {                                                                                      \
-       lttng_ust_tracepoint_probe_register(provider_name, event_name, func, data,              \
+       lttng_ust_tracepoint_provider_register(provider_name, event_name, func, data,           \
                lttng_ust_tracepoint_##_provider##___##_name.signature);                        \
 }                                                                                      \
 static inline                                                                          \
@@ -226,14 +234,27 @@ static inline                                                                             \
 void lttng_ust_tracepoint_unregister_##_provider##___##_name(char *provider_name, char *event_name, \
                void (*func)(void), void *data)                                         \
 {                                                                                      \
-       lttng_ust_tracepoint_probe_unregister(provider_name, event_name, func, data);           \
+       lttng_ust_tracepoint_provider_unregister(provider_name, event_name, func, data);                \
 }
 
-extern int lttng_ust_tracepoint_probe_register(const char *provider_name, const char *event_name,
+/*
+ * Registration of tracepoint provider probe functions with
+ * lttng_ust_tracepoint_provider_register, unregistration with
+ * lttng_ust_tracepoint_provider_unregister.
+ */
+int lttng_ust_tracepoint_provider_register(const char *provider_name, const char *event_name,
                void (*func)(void), void *data, const char *signature);
-extern int lttng_ust_tracepoint_probe_unregister(const char *provider_name, const char *event_name,
+int lttng_ust_tracepoint_provider_unregister(const char *provider_name, const char *event_name,
                void (*func)(void), void *data);
 
+/*
+ * Registration of tracepoint instrumentation modules with lttng_ust_tracepoint_module_register,
+ * unregistration with lttng_ust_tracepoint_module_unregister.
+ */
+int lttng_ust_tracepoint_module_register(struct lttng_ust_tracepoint * const *tracepoints_start,
+                             int tracepoints_count);
+int lttng_ust_tracepoint_module_unregister(struct lttng_ust_tracepoint * const *tracepoints_start);
+
 /*
  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
  * shared across objects in a module/main executable.
@@ -251,9 +272,9 @@ struct lttng_ust_tracepoint_dlopen {
 
        void *liblttngust_handle;
 
-       int (*lttng_ust_tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start,
+       int (*lttng_ust_tracepoint_module_register)(struct lttng_ust_tracepoint * const *tracepoints_start,
                int tracepoints_count);
-       int (*lttng_ust_tracepoint_unregister_lib)(struct lttng_ust_tracepoint * const *tracepoints_start);
+       int (*lttng_ust_tracepoint_module_unregister)(struct lttng_ust_tracepoint * const *tracepoints_start);
        void (*rcu_read_lock_sym)(void);
        void (*rcu_read_unlock_sym)(void);
        void *(*rcu_dereference_sym)(void *p);
@@ -372,9 +393,58 @@ lttng_ust_tracepoint__init_urcu_sym(void)
 }
 #endif
 
+/*
+ * Use getenv() directly and bypass lttng-ust helper functions
+ * because we may not have access to lttng-ust shared libraries.
+ */
+#ifdef LTTNG_UST_DEBUG
+static inline
+bool lttng_ust_tracepoint_logging_debug_enabled(void)
+{
+       return true;
+}
+#else /* #ifdef LTTNG_UST_DEBUG */
+static inline
+bool lttng_ust_tracepoint_logging_debug_enabled(void)
+{
+       return getenv("LTTNG_UST_DEBUG");
+}
+#endif /* #ifdef LTTNG_UST_DEBUG */
+
+#ifdef LTTNG_UST_ABORT_ON_CRITICAL
+static inline
+bool lttng_ust_tracepoint_logging_abort_on_critical_enabled(void)
+{
+       return true;
+}
+#else /* #ifdef LTTNG_UST_ABORT_ON_CRITICAL */
+static inline
+bool lttng_ust_tracepoint_logging_abort_on_critical_enabled(void)
+{
+       return getenv("LTTNG_UST_ABORT_ON_CRITICAL");
+}
+#endif
+
+#define LTTNG_UST_TRACEPOINT_THIS_IP           \
+       ({ __label__ here; here: &&here; })
+
+static void
+lttng_ust_tracepoints_print_disabled_message(void)
+{
+       if (lttng_ust_tracepoint_logging_debug_enabled())
+               fprintf(stderr, "lttng-ust-tracepoint [%ld]: Critical: dlopen() failed to find '%s', tracepoints in this binary won't be registered. "
+                       "(at addr=%p in %s() at " __FILE__ ":" lttng_ust_stringify(__LINE__) ")\n",
+                       (long) getpid(),
+                       LTTNG_UST_TRACEPOINT_LIB_SONAME,
+                       LTTNG_UST_TRACEPOINT_THIS_IP,
+                       __func__);
+       if (lttng_ust_tracepoint_logging_abort_on_critical_enabled())
+               abort();
+}
+
 static void
 lttng_ust__tracepoints__init(void)
-       lttng_ust_notrace __attribute__((constructor));
+       lttng_ust_notrace __attribute__((constructor(LTTNG_UST_CONSTRUCTOR_PRIO)));
 static void
 lttng_ust__tracepoints__init(void)
 {
@@ -390,14 +460,16 @@ lttng_ust__tracepoints__init(void)
        if (!lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle)
                lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle =
                        dlopen(LTTNG_UST_TRACEPOINT_LIB_SONAME, RTLD_NOW | RTLD_GLOBAL);
-       if (!lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle)
+       if (!lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle) {
+               lttng_ust_tracepoints_print_disabled_message();
                return;
+       }
        lttng_ust_tracepoint__init_urcu_sym();
 }
 
 static void
 lttng_ust__tracepoints__destroy(void)
-       lttng_ust_notrace __attribute__((destructor));
+       lttng_ust_notrace __attribute__((destructor(LTTNG_UST_CONSTRUCTOR_PRIO)));
 static void
 lttng_ust__tracepoints__destroy(void)
 {
@@ -439,8 +511,30 @@ lttng_ust__tracepoints__destroy(void)
 # endif
 #endif /* #if LTTNG_UST_COMPAT_API(0) */
 
+#if LTTNG_UST_COMPAT_API(0)
+#define tracepoint                     lttng_ust_tracepoint
+#define do_tracepoint                  lttng_ust_do_tracepoint
+#define tracepoint_enabled             lttng_ust_tracepoint_enabled
+#define TP_ARGS                                LTTNG_UST_TP_ARGS
+#endif /* #if LTTNG_UST_COMPAT_API(0) */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _LTTNG_UST_TRACEPOINT_H */
+
+/* The following declarations must be outside re-inclusion protection. */
+
 #ifdef LTTNG_UST_TRACEPOINT_DEFINE
 
+#ifndef _LTTNG_UST_TRACEPOINT_DEFINE_ONCE
+#define _LTTNG_UST_TRACEPOINT_DEFINE_ONCE
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*
  * These weak symbols, the constructor, and destructor take care of
  * registering only _one_ instance of the tracepoints per shared-ojbect
@@ -480,9 +574,11 @@ extern struct lttng_ust_tracepoint * const __stop_lttng_ust_tracepoints_ptrs[]
  */
 #define LTTNG_UST__TP_EXTRACT_STRING(...)      #__VA_ARGS__
 
+#undef LTTNG_UST__DEFINE_TRACEPOINT
 #define LTTNG_UST__DEFINE_TRACEPOINT(_provider, _name, _args)                          \
        lttng_ust_tracepoint_validate_name_len(_provider, _name);               \
-       extern int lttng_ust_tracepoint_provider_##_provider;                           \
+       extern int lttng_ust_tracepoint_provider_##_provider                    \
+               LTTNG_UST__TRACEPOINT_PROVIDER_DEFINITION_VISIBILITY;           \
        static const char lttng_ust_tp_provider_strtab_##_provider##___##_name[]        \
                __attribute__((section("lttng_ust_tracepoints_strings"))) =             \
                        #_provider;                                             \
@@ -490,7 +586,8 @@ extern struct lttng_ust_tracepoint * const __stop_lttng_ust_tracepoints_ptrs[]
                __attribute__((section("lttng_ust_tracepoints_strings"))) =             \
                        #_name;                                                 \
        struct lttng_ust_tracepoint lttng_ust_tracepoint_##_provider##___##_name        \
-               __attribute__((section("lttng_ust_tracepoints"))) = {                   \
+               __attribute__((section("lttng_ust_tracepoints")))               \
+               LTTNG_UST__TRACEPOINT_DEFINITION_VISIBILITY = {                 \
                        sizeof(struct lttng_ust_tracepoint),                    \
                        lttng_ust_tp_provider_strtab_##_provider##___##_name,           \
                        lttng_ust_tp_name_strtab_##_provider##___##_name,               \
@@ -507,7 +604,7 @@ extern struct lttng_ust_tracepoint * const __stop_lttng_ust_tracepoints_ptrs[]
 
 static void
 lttng_ust__tracepoints__ptrs_init(void)
-       lttng_ust_notrace __attribute__((constructor));
+       lttng_ust_notrace __attribute__((constructor(LTTNG_UST_CONSTRUCTOR_PRIO)));
 static void
 lttng_ust__tracepoints__ptrs_init(void)
 {
@@ -518,18 +615,20 @@ lttng_ust__tracepoints__ptrs_init(void)
        if (!lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle)
                lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle =
                        dlopen(LTTNG_UST_TRACEPOINT_LIB_SONAME, RTLD_NOW | RTLD_GLOBAL);
-       if (!lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle)
+       if (!lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle) {
+               lttng_ust_tracepoints_print_disabled_message();
                return;
+       }
        if (!lttng_ust_tracepoint_destructors_syms_ptr)
                lttng_ust_tracepoint_destructors_syms_ptr = &lttng_ust_tracepoint_destructors_syms;
-       lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_register_lib =
+       lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_module_register =
                URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int),
                                dlsym(lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle,
-                                       "lttng_ust_tracepoint_register_lib"));
-       lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_unregister_lib =
+                                       "lttng_ust_tracepoint_module_register"));
+       lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_module_unregister =
                URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *),
                                dlsym(lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle,
-                                       "lttng_ust_tracepoint_unregister_lib"));
+                                       "lttng_ust_tracepoint_module_unregister"));
        lttng_ust_tracepoint_destructors_syms_ptr->tracepoint_disable_destructors =
                URCU_FORCE_CAST(void (*)(void),
                                dlsym(lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle,
@@ -539,8 +638,8 @@ lttng_ust__tracepoints__ptrs_init(void)
                                dlsym(lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle,
                                        "lttng_ust_tp_get_destructors_state"));
        lttng_ust_tracepoint__init_urcu_sym();
-       if (lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_register_lib) {
-               lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_register_lib(__start_lttng_ust_tracepoints_ptrs,
+       if (lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_module_register) {
+               lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_module_register(__start_lttng_ust_tracepoints_ptrs,
                                __stop_lttng_ust_tracepoints_ptrs -
                                __start_lttng_ust_tracepoints_ptrs);
        }
@@ -548,7 +647,7 @@ lttng_ust__tracepoints__ptrs_init(void)
 
 static void
 lttng_ust__tracepoints__ptrs_destroy(void)
-       lttng_ust_notrace __attribute__((destructor));
+       lttng_ust_notrace __attribute__((destructor(LTTNG_UST_CONSTRUCTOR_PRIO)));
 static void
 lttng_ust__tracepoints__ptrs_destroy(void)
 {
@@ -560,8 +659,8 @@ lttng_ust__tracepoints__ptrs_destroy(void)
                lttng_ust_tracepoint_dlopen_ptr = &lttng_ust_tracepoint_dlopen;
        if (!lttng_ust_tracepoint_destructors_syms_ptr)
                lttng_ust_tracepoint_destructors_syms_ptr = &lttng_ust_tracepoint_destructors_syms;
-       if (lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_unregister_lib)
-               lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_unregister_lib(__start_lttng_ust_tracepoints_ptrs);
+       if (lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_module_unregister)
+               lttng_ust_tracepoint_dlopen_ptr->lttng_ust_tracepoint_module_unregister(__start_lttng_ust_tracepoints_ptrs);
        if (lttng_ust_tracepoint_dlopen_ptr->liblttngust_handle
                        && lttng_ust_tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state
                        && lttng_ust_tracepoint_destructors_syms_ptr->tracepoint_get_destructors_state()
@@ -575,26 +674,51 @@ lttng_ust__tracepoints__ptrs_destroy(void)
        }
 }
 
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _LTTNG_UST_TRACEPOINT_DEFINE_ONCE */
+
 #else /* LTTNG_UST_TRACEPOINT_DEFINE */
 
+#undef LTTNG_UST__DEFINE_TRACEPOINT
 #define LTTNG_UST__DEFINE_TRACEPOINT(_provider, _name, _args)
 
 #endif /* #else LTTNG_UST_TRACEPOINT_DEFINE */
 
-#if LTTNG_UST_COMPAT_API(0)
-#define tracepoint                     lttng_ust_tracepoint
-#define do_tracepoint                  lttng_ust_do_tracepoint
-#define tracepoint_enabled             lttng_ust_tracepoint_enabled
-#define TP_ARGS                                LTTNG_UST_TP_ARGS
-#endif /* #if LTTNG_UST_COMPAT_API(0) */
+/*
+ * LTTNG_UST_TRACEPOINT_HIDDEN_DEFINITION: Define this before including
+ * a tracepoint instrumentation header to hide symbols associated with
+ * tracepoint module instrumentation. This is useful if all compile
+ * units using the lttng_ust_tracepoint(),
+ * lttng_ust_tracepoint_enabled() and lttng_ust_do_tracepoint() macros
+ * is within the same module as the compile unit including the
+ * tracepoint header after defining LTTNG_UST_TRACEPOINT_DEFINE.
+ */
 
-#ifdef __cplusplus
-}
+#undef LTTNG_UST__TRACEPOINT_DEFINITION_VISIBILITY
+#ifdef LTTNG_UST_TRACEPOINT_HIDDEN_DEFINITION
+#define LTTNG_UST__TRACEPOINT_DEFINITION_VISIBILITY            __attribute__((visibility("hidden")))
+#else
+#define LTTNG_UST__TRACEPOINT_DEFINITION_VISIBILITY            __attribute__((visibility("default")))
 #endif
 
-#endif /* _LTTNG_TRACEPOINT_H */
-
-/* The following declarations must be outside re-inclusion protection. */
+/*
+ * LTTNG_UST_TRACEPOINT_PROVIDER_HIDDEN_DEFINITION: Define this before
+ * including a tracepoint instrumentation header to hide symbols
+ * associated with the tracepoint provider. This is useful if the
+ * tracepoint definition (including the header after defining
+ * LTTNG_UST_TRACEPOINT_DEFINE) is in the same module as the provider
+ * (including the header after defining
+ * LTTNG_UST_TRACEPOINT_CREATE_PROBES).
+ */
+#undef LTTNG_UST__TRACEPOINT_PROVIDER_DEFINITION_VISIBILITY
+#ifdef LTTNG_UST_TRACEPOINT_PROVIDER_HIDDEN_DEFINITION
+#define LTTNG_UST__TRACEPOINT_PROVIDER_DEFINITION_VISIBILITY   __attribute__((visibility("hidden")))
+#else
+#define LTTNG_UST__TRACEPOINT_PROVIDER_DEFINITION_VISIBILITY   __attribute__((visibility("default")))
+#endif
 
 #ifndef LTTNG_UST_TRACEPOINT_ENUM
 
@@ -734,14 +858,17 @@ lttng_ust__tracepoints__ptrs_destroy(void)
 
 #define LTTNG_UST_TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 
-#define LTTNG_UST_TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)   \
+#define LTTNG_UST_TRACEPOINT_EVENT_INSTANCE(template_provider, template_name, provider, name, args)    \
        LTTNG_UST__DECLARE_TRACEPOINT(provider, name, LTTNG_UST__TP_PARAMS(args))               \
        LTTNG_UST__DEFINE_TRACEPOINT(provider, name, LTTNG_UST__TP_PARAMS(args))
 
 #if LTTNG_UST_COMPAT_API(0)
 #define TRACEPOINT_EVENT               LTTNG_UST_TRACEPOINT_EVENT
 #define TRACEPOINT_EVENT_CLASS         LTTNG_UST_TRACEPOINT_EVENT_CLASS
-#define TRACEPOINT_EVENT_INSTANCE      LTTNG_UST_TRACEPOINT_EVENT_INSTANCE
+#define TRACEPOINT_EVENT_INSTANCE(_provider, _template, _name, args)   \
+       LTTNG_UST_TRACEPOINT_EVENT_INSTANCE(_provider, _template,       \
+               _provider, _name, LTTNG_UST__TP_PARAMS(args))
+
 #endif /* #if LTTNG_UST_COMPAT_API(0) */
 
 #endif /* #ifndef LTTNG_UST_TRACEPOINT_EVENT */
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