/*

 * Copyright (C) 2014  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; version 2.1 of

 * the License.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA

 */

#define _GNU_SOURCE

#include <error.h>

#include <dlfcn.h>

#include <stdlib.h>

#include <usterr-signal-safe.h>

#include <lttng/ust-clock.h>

#include <urcu/system.h>

#include <urcu/arch.h>

#include "clock.h"

#include "getenv.h"

struct lttng_trace_clock *lttng_trace_clock;

static

struct lttng_trace_clock user_tc;

static

void *clock_handle;

int lttng_ust_trace_clock_set_read64_cb(uint64_t (*read64)(void))

{

	if (CMM_LOAD_SHARED(lttng_trace_clock))

		return -EBUSY;

	user_tc.read64 = read64;

	return 0;

}

int lttng_ust_trace_clock_set_freq_cb(uint64_t (*freq)(void))

{

	if (CMM_LOAD_SHARED(lttng_trace_clock))

		return -EBUSY;

	user_tc.freq = freq;

	return 0;

}

int lttng_ust_trace_clock_set_uuid_cb(int (*uuid)(char *uuid))

{

	if (CMM_LOAD_SHARED(lttng_trace_clock))

		return -EBUSY;

	user_tc.uuid = uuid;

	return 0;

}

int lttng_ust_trace_clock_set_name_cb(const char *(*name)(void))

{

	if (CMM_LOAD_SHARED(lttng_trace_clock))

		return -EBUSY;

	user_tc.name = name;

	return 0;

}

int lttng_ust_trace_clock_set_description_cb(const char *(*description)(void))

{

	if (CMM_LOAD_SHARED(lttng_trace_clock))

		return -EBUSY;

	user_tc.description = description;

	return 0;

}

int lttng_ust_enable_trace_clock_override(void)

{

	if (CMM_LOAD_SHARED(lttng_trace_clock))

		return -EBUSY;

	if (!user_tc.read64)

		return -EINVAL;

	if (!user_tc.freq)

		return -EINVAL;

	if (!user_tc.name)

		return -EINVAL;

	if (!user_tc.description)

		return -EINVAL;

	/* Use default uuid cb when NULL */

	cmm_smp_mb();	/* Store callbacks before trace clock */

	CMM_STORE_SHARED(lttng_trace_clock, &user_tc);

	return 0;

}

void lttng_ust_clock_init(void)

{

	const char *libname;

	void (*libinit)(void);

	if (clock_handle)

		return;

	libname = lttng_secure_getenv("LTTNG_UST_CLOCK_PLUGIN");

	if (!libname)

		return;

	clock_handle = dlopen(libname, RTLD_NOW);

	if (!clock_handle) {

		PERROR("Cannot load LTTng UST clock override library %s",

			libname);

		return;

	}

	dlerror();

	libinit = (void (*)(void)) dlsym(clock_handle,

		"lttng_ust_clock_plugin_init");

	if (!libinit) {

		PERROR("Cannot find LTTng UST clock override library %s initialization function lttng_ust_clock_plugin_init()",

			libname);

		return;

	}

	libinit();

}