fix: pthread_setname_np fails on longer tread names

[deliverable/lttng-ust.git] / liblttng-ust / compat.h

#ifndef _UST_COMPAT_H
#define _UST_COMPAT_H

/*
 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 * Copyright (C) 2016 Raphaël Beamonte <raphael.beamonte@gmail.com>
 * Copyright (C) 2020 Michael Jeanson <mjeanson@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; only
 * 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
 */

#include <pthread.h>
#include <errno.h>
#include <string.h>

#include <lttng/ust-abi.h>

#define LTTNG_UST_PROCNAME_SUFFIX "-ust"


#if defined(HAVE_PTHREAD_SETNAME_NP_WITH_TID)
static inline
int lttng_pthread_setname_np(const char *name)
{
	return pthread_setname_np(pthread_self(), name);
}

static inline
int lttng_pthread_getname_np(char *name, size_t len)
{
	return pthread_getname_np(pthread_self(), name, len);
}
#elif defined(HAVE_PTHREAD_SETNAME_NP_WITHOUT_TID)
static inline
int lttng_pthread_setname_np(const char *name)
{
	return pthread_setname_np(name);
}

static inline
int lttng_pthread_getname_np(char *name, size_t len)
{
	return pthread_getname_np(name, len);
}
#elif defined(HAVE_PTHREAD_SET_NAME_NP_WITH_TID)

#include <pthread_np.h>
static inline
int lttng_pthread_setname_np(const char *name)
{
	/* Replicate pthread_setname_np's behavior */
	if (strnlen(name, LTTNG_UST_ABI_PROCNAME_LEN) >= LTTNG_UST_ABI_PROCNAME_LEN) {
		return ERANGE;
	}

	pthread_set_name_np(pthread_self(), name);
	return 0;
}

static inline
int lttng_pthread_getname_np(char *name, size_t len)
{
	pthread_get_name_np(pthread_self(), name, len);
	return 0;
}
#elif defined(__linux__)

/* Fallback on prtctl on Linux */
#include <sys/prctl.h>

static inline
int lttng_pthread_setname_np(const char *name)
{
	/* Replicate pthread_setname_np's behavior */
	if (strnlen(name, LTTNG_UST_ABI_PROCNAME_LEN) >= LTTNG_UST_ABI_PROCNAME_LEN) {
		return ERANGE;
	}
	return prctl(PR_SET_NAME, name, 0, 0, 0);
}

static inline
int lttng_pthread_getname_np(char *name, size_t len)
{
	return prctl(PR_GET_NAME, name, 0, 0, 0);
}

#else
#error "Please add pthread name support for your OS."
#endif

/*
 * If a pthread setname/set_name function is available, declare
 * the setustprocname() function that will add '-ust' to the end
 * of the current process name, while truncating it if needed.
 */
static inline
int lttng_ust_setustprocname(void)
{
	int ret = 0, len;
	char name[LTTNG_UST_ABI_PROCNAME_LEN];
	int limit = LTTNG_UST_ABI_PROCNAME_LEN - strlen(LTTNG_UST_PROCNAME_SUFFIX) - 1;

	/*
	 * Get the current thread name.
	 */
	ret = lttng_pthread_getname_np(name, LTTNG_UST_ABI_PROCNAME_LEN);
	if (ret) {
		goto error;
	}

	len = strlen(name);
	if (len > limit) {
		len = limit;
	}

	ret = sprintf(name + len, LTTNG_UST_PROCNAME_SUFFIX);
	if (ret != strlen(LTTNG_UST_PROCNAME_SUFFIX)) {
		goto error;
	}

	ret = lttng_pthread_setname_np(name);

error:
	return ret;
}

#include <errno.h>

#ifndef ENODATA
#define ENODATA	ENOMSG
#endif

#endif /* _UST_COMPAT_H */