projects / lttng-ust.git / blame
| Commit | Line | Data |
|---|---|---|
| 247c2ecd MJ |
1 | /* |
| 2 | * SPDX-License-Identifier: LGPL-2.1-only | |
| 3 | * | |
| 4 | * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
| 5 | */ | |
| 6 | ||
| 7 | #define _LGPL_SOURCE | |
| 8 | #include <error.h> | |
| 9 | #include <dlfcn.h> | |
| 10 | #include <stdlib.h> | |
| 11 | #include "common/logging.h" | |
| 12 | #include <urcu/system.h> | |
| 13 | #include <urcu/arch.h> | |
| 14 | ||
| 910dcd72 | 15 | #include "common/getenv.h" |
| 247c2ecd MJ |
16 | #include "lib/lttng-ust/getcpu.h" |
| 17 | ||
| 18 | /* Function pointer to the current getcpu callback. */ | |
| 19 | int (*lttng_ust_get_cpu_sym)(void); | |
| 20 | ||
| 21 | static | |
| 22 | void *getcpu_plugin_handle; | |
| 23 | ||
| 24 | /* | |
| 25 | * Override the user provided getcpu implementation. | |
| 26 | */ | |
| 27 | int lttng_ust_getcpu_override(int (*getcpu)(void)) | |
| 28 | { | |
| 29 | CMM_STORE_SHARED(lttng_ust_get_cpu_sym, getcpu); | |
| 30 | return 0; | |
| 31 | } | |
| 32 | ||
| 33 | /* | |
| 34 | * Initialize the getcpu plugin if it's present. | |
| 35 | */ | |
| 36 | void lttng_ust_getcpu_plugin_init(void) | |
| 37 | { | |
| 38 | const char *libname; | |
| 39 | void (*getcpu_plugin_init)(void); | |
| 40 | ||
| 41 | /* If a plugin is already loaded, do nothing. */ | |
| 42 | if (getcpu_plugin_handle) | |
| 43 | return; | |
| 44 | ||
| 45 | /* | |
| 46 | * If the LTTNG_UST_GETCPU_PLUGIN environment variable is undefined, do | |
| 47 | * nothing. | |
| 48 | */ | |
| 49 | libname = lttng_ust_getenv("LTTNG_UST_GETCPU_PLUGIN"); | |
| 50 | if (!libname) | |
| 51 | return; | |
| 52 | ||
| 53 | /* | |
| 54 | * Thy to dlopen the getcpu plugin shared object specified in | |
| 55 | * LTTNG_UST_GETCPU_PLUGIN. | |
| 56 | */ | |
| 57 | getcpu_plugin_handle = dlopen(libname, RTLD_NOW); | |
| 58 | if (!getcpu_plugin_handle) { | |
| 59 | PERROR("Cannot load LTTng UST getcpu override library %s", | |
| 60 | libname); | |
| 61 | return; | |
| 62 | } | |
| 63 | dlerror(); | |
| 64 | ||
| 65 | /* Locate the getcpu plugin init function in the shared object. */ | |
| 66 | getcpu_plugin_init = (void (*)(void)) dlsym(getcpu_plugin_handle, | |
| 67 | "lttng_ust_getcpu_plugin_init"); | |
| 68 | if (!getcpu_plugin_init) { | |
| 69 | PERROR("Cannot find LTTng UST getcpu override library %s initialization function lttng_ust_getcpu_plugin_init()", | |
| 70 | libname); | |
| 71 | return; | |
| 72 | } | |
| 73 | ||
| 74 | /* Run the user provided getcpu plugin init function. */ | |
| 75 | getcpu_plugin_init(); | |
| 76 | } |