Blame liblttng-ust/lttng-getcpu.c

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/*
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 * Copyright (C) 2014  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; version 2.1 of
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 * the License.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
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 */
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#define _GNU_SOURCE
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#include <error.h>
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#include <dlfcn.h>
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#include <stdlib.h>
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#include <usterr-signal-safe.h>
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#include <lttng/ust-getcpu.h>
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#include <urcu/system.h>
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#include <urcu/arch.h>
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#include "getenv.h"
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#include "../libringbuffer/getcpu.h"
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int (*lttng_get_cpu)(void);
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static
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void *getcpu_handle;
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int lttng_ust_getcpu_override(int (*getcpu)(void))
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{
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	CMM_STORE_SHARED(lttng_get_cpu, getcpu);
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	return 0;
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}
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void lttng_ust_getcpu_init(void)
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{
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	const char *libname;
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	void (*libinit)(void);
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	if (getcpu_handle)
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		return;
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	libname = lttng_secure_getenv("LTTNG_UST_GETCPU_PLUGIN");
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	if (!libname)
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		return;
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	getcpu_handle = dlopen(libname, RTLD_NOW);
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	if (!getcpu_handle) {
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		PERROR("Cannot load LTTng UST getcpu override library %s",
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			libname);
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		return;
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	}
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	dlerror();
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	libinit = (void (*)(void)) dlsym(getcpu_handle,
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		"lttng_ust_getcpu_plugin_init");
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	if (!libinit) {
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		PERROR("Cannot find LTTng UST getcpu override library %s initialization function lttng_ust_getcpu_plugin_init()",
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			libname);
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		return;
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	}
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	libinit();
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}