X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=include%2Flttng%2Ftracepoint.h;h=71f3e36c856af7ddffdddf23e5e8e57cc23e82fc;hb=f641d544ea2630c5a52c0cbc5db947d34461cea7;hp=51eafdeb5a4cce36e957ede0d5af31557fb5d803;hpb=05e8ff1f80c9a6dcd7db559c7a39b4c46e85e2a7;p=lttng-ust.git diff --git a/include/lttng/tracepoint.h b/include/lttng/tracepoint.h index 51eafdeb..71f3e36c 100644 --- a/include/lttng/tracepoint.h +++ b/include/lttng/tracepoint.h @@ -1,28 +1,12 @@ -#ifndef _LTTNG_TRACEPOINT_H -#define _LTTNG_TRACEPOINT_H - /* - * Copyright 2011-2012 - Mathieu Desnoyers - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this software and associated documentation files (the "Software"), to deal - * in the Software without restriction, including without limitation the rights - * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell - * copies of the Software, and to permit persons to whom the Software is - * furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE - * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, - * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE - * SOFTWARE. + * SPDX-License-Identifier: MIT + * + * Copyright (C) 2011-2012 Mathieu Desnoyers */ +#ifndef _LTTNG_TRACEPOINT_H +#define _LTTNG_TRACEPOINT_H + #include #include #include @@ -226,8 +210,18 @@ extern int __tracepoint_probe_unregister(const char *name, void (*func)(void), /* * tracepoint dynamic linkage handling (callbacks). Hidden visibility: * shared across objects in a module/main executable. + * + * IMPORTANT: this structure is part of the ABI between instrumented + * applications 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_tracepoint_dlopen { + uint32_t struct_size; + void *liblttngust_handle; int (*tracepoint_register_lib)(struct lttng_ust_tracepoint * const *tracepoints_start, @@ -236,6 +230,8 @@ struct lttng_ust_tracepoint_dlopen { void (*rcu_read_lock_sym)(void); void (*rcu_read_unlock_sym)(void); void *(*rcu_dereference_sym)(void *p); + + /* End of base ABI. Fields below should be used after checking struct_size. */ }; extern struct lttng_ust_tracepoint_dlopen tracepoint_dlopen; @@ -251,7 +247,9 @@ int __tracepoint_registered int __tracepoint_ptrs_registered __attribute__((weak, visibility("hidden"))); struct lttng_ust_tracepoint_dlopen tracepoint_dlopen - __attribute__((weak, visibility("hidden"))); + __attribute__((weak, visibility("hidden"))) = { + .struct_size = sizeof(struct lttng_ust_tracepoint_dlopen), +}; /* * Deal with gcc O1 optimisation issues with weak hidden symbols. gcc * 4.8 and prior does not have the same behavior for symbol scoping on @@ -269,18 +267,31 @@ struct lttng_ust_tracepoint_dlopen *tracepoint_dlopen_ptr * Tracepoint dynamic linkage handling (callbacks). Hidden visibility: shared * across objects in a module/main executable. The callbacks are used to * control and check if the destructors should be executed. + * + * IMPORTANT: this structure is part of the ABI between instrumented + * applications 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_tracepoint_destructors_syms { - int *old_tracepoint_disable_destructors; + uint32_t struct_size; + void (*tracepoint_disable_destructors)(void); int (*tracepoint_get_destructors_state)(void); + + /* End of base ABI. Fields below should be used after checking struct_size. */ }; extern struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms; extern struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr; struct lttng_ust_tracepoint_destructors_syms tracepoint_destructors_syms - __attribute__((weak, visibility("hidden"))); + __attribute__((weak, visibility("hidden"))) = { + .struct_size = sizeof(struct lttng_ust_tracepoint_destructors_syms), +}; struct lttng_ust_tracepoint_destructors_syms *tracepoint_destructors_syms_ptr __attribute__((weak, visibility("hidden"))); @@ -293,7 +304,6 @@ static inline void tracepoint_disable_destructors(void) if (tracepoint_dlopen_ptr->liblttngust_handle && tracepoint_destructors_syms_ptr->tracepoint_disable_destructors) tracepoint_destructors_syms_ptr->tracepoint_disable_destructors(); - *tracepoint_destructors_syms_ptr->old_tracepoint_disable_destructors = 1; } #ifndef _LGPL_SOURCE @@ -384,19 +394,6 @@ __tracepoints__destroy(void) */ return; } - /* - * Lookup if destructors must be executed using the old method. - */ - if (tracepoint_destructors_syms_ptr->old_tracepoint_disable_destructors - && *tracepoint_destructors_syms_ptr->old_tracepoint_disable_destructors) { - /* - * The old_tracepoint_disable_destructors symbol was found with - * dlsym but its value is 1 meaning that destructors must not - * be executed. - */ - return; - } - ret = dlclose(tracepoint_dlopen_ptr->liblttngust_handle); if (ret) { fprintf(stderr, "Error (%d) in dlclose\n", ret); @@ -445,14 +442,13 @@ extern struct lttng_ust_tracepoint * const __stop___tracepoints_ptrs[] __attribute__((section("__tracepoints_strings"))) = \ #_provider ":" #_name; \ struct lttng_ust_tracepoint __tracepoint_##_provider##___##_name \ - __attribute__((section("__tracepoints"))) = \ - { \ + __attribute__((section("__tracepoints"))) = { \ + sizeof(struct lttng_ust_tracepoint), \ __tp_strtab_##_provider##___##_name, \ 0, \ NULL, \ _TRACEPOINT_UNDEFINED_REF(_provider), \ _TP_EXTRACT_STRING(_args), \ - { }, \ }; \ static struct lttng_ust_tracepoint * \ __tracepoint_ptr_##_provider##___##_name \ @@ -479,15 +475,11 @@ __tracepoints__ptrs_init(void) tracepoint_dlopen_ptr->tracepoint_register_lib = URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *, int), dlsym(tracepoint_dlopen_ptr->liblttngust_handle, - "tracepoint_register_lib2")); + "tracepoint_register_lib")); tracepoint_dlopen_ptr->tracepoint_unregister_lib = URCU_FORCE_CAST(int (*)(struct lttng_ust_tracepoint * const *), dlsym(tracepoint_dlopen_ptr->liblttngust_handle, - "tracepoint_unregister_lib2")); - tracepoint_destructors_syms_ptr->old_tracepoint_disable_destructors = - URCU_FORCE_CAST(int *, - dlsym(tracepoint_dlopen_ptr->liblttngust_handle, - "__tracepoints__disable_destructors")); + "tracepoint_unregister_lib")); tracepoint_destructors_syms_ptr->tracepoint_disable_destructors = URCU_FORCE_CAST(void (*)(void), dlsym(tracepoint_dlopen_ptr->liblttngust_handle,