[lttng-modules.git] / lttng-context-ppid.c

/*
 * lttng-context-ppid.c
 *
 * LTTng PPID context.
 *
 * Copyright (C) 2009-2012 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; 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 <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include "lttng-events.h"
#include "wrapper/ringbuffer/frontend_types.h"
#include "wrapper/vmalloc.h"
#include "lttng-tracer.h"

static
size_t ppid_get_size(size_t offset)
{
	size_t size = 0;

	size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
	size += sizeof(pid_t);
	return size;
}

static
void ppid_record(struct lttng_ctx_field *field,
		 struct lib_ring_buffer_ctx *ctx,
		 struct lttng_channel *chan)
{
	pid_t ppid;

	/*
	 * TODO: when we eventually add RCU subsystem instrumentation,
	 * taking the rcu read lock here will trigger RCU tracing
	 * recursively. We should modify the kernel synchronization so
	 * it synchronizes both for RCU and RCU sched, and rely on
	 * rcu_read_lock_sched_notrace.
	 */
	rcu_read_lock();
	ppid = task_tgid_nr(current->real_parent);
	rcu_read_unlock();
	lib_ring_buffer_align_ctx(ctx, lttng_alignof(ppid));
	chan->ops->event_write(ctx, &ppid, sizeof(ppid));
}

static
void ppid_get_value(struct lttng_ctx_field *field,
		union lttng_ctx_value *value)
{
	pid_t ppid;

	/*
	 * TODO: when we eventually add RCU subsystem instrumentation,
	 * taking the rcu read lock here will trigger RCU tracing
	 * recursively. We should modify the kernel synchronization so
	 * it synchronizes both for RCU and RCU sched, and rely on
	 * rcu_read_lock_sched_notrace.
	 */
	rcu_read_lock();
	ppid = task_tgid_nr(current->real_parent);
	rcu_read_unlock();
	value->s64 = ppid;
}

int lttng_add_ppid_to_ctx(struct lttng_ctx **ctx)
{
	struct lttng_ctx_field *field;

	field = lttng_append_context(ctx);
	if (!field)
		return -ENOMEM;
	if (lttng_find_context(*ctx, "ppid")) {
		lttng_remove_context_field(ctx, field);
		return -EEXIST;
	}
	field->event_field.name = "ppid";
	field->event_field.type.atype = atype_integer;
	field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
	field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	field->event_field.type.u.basic.integer.base = 10;
	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	field->get_size = ppid_get_size;
	field->record = ppid_record;
	field->get_value = ppid_get_value;
	lttng_context_update(*ctx);
	wrapper_vmalloc_sync_all();
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_ppid_to_ctx);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Linux Trace Toolkit PPID Context");
MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
	LTTNG_MODULES_EXTRAVERSION);
Commit	Line	Data
b64bc438	1	/*
886d51a3	2	* lttng-context-ppid.c
b64bc438 MD	3	*
	4	* LTTng PPID context.
	5	*
886d51a3 MD	6	* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
b64bc438 MD	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/slab.h>
	25	#include <linux/sched.h>
	26	#include <linux/syscalls.h>
a90917c3	27	#include "lttng-events.h"
b64bc438 MD	28	#include "wrapper/ringbuffer/frontend_types.h"
b64bc438 MD	29	#include "wrapper/vmalloc.h"
a90917c3	30	#include "lttng-tracer.h"
b64bc438 MD	31
	32	static
	33	size_t ppid_get_size(size_t offset)
	34	{
	35	size_t size = 0;
	36
a90917c3	37	size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
b64bc438 MD	38	size += sizeof(pid_t);
	39	return size;
	40	}
	41
	42	static
	43	void ppid_record(struct lttng_ctx_field *field,
	44	struct lib_ring_buffer_ctx *ctx,
a90917c3	45	struct lttng_channel *chan)
b64bc438 MD	46	{
	47	pid_t ppid;
	48
1638c9b4 MD	49	/*
	50	* TODO: when we eventually add RCU subsystem instrumentation,
	51	* taking the rcu read lock here will trigger RCU tracing
	52	* recursively. We should modify the kernel synchronization so
	53	* it synchronizes both for RCU and RCU sched, and rely on
	54	* rcu_read_lock_sched_notrace.
	55	*/
b64bc438 MD	56	rcu_read_lock();
	57	ppid = task_tgid_nr(current->real_parent);
	58	rcu_read_unlock();
a90917c3	59	lib_ring_buffer_align_ctx(ctx, lttng_alignof(ppid));
b64bc438 MD	60	chan->ops->event_write(ctx, &ppid, sizeof(ppid));
	61	}
	62
f127e61e MD	63	static
	64	void ppid_get_value(struct lttng_ctx_field *field,
	65	union lttng_ctx_value *value)
	66	{
	67	pid_t ppid;
	68
	69	/*
	70	* TODO: when we eventually add RCU subsystem instrumentation,
	71	* taking the rcu read lock here will trigger RCU tracing
	72	* recursively. We should modify the kernel synchronization so
	73	* it synchronizes both for RCU and RCU sched, and rely on
	74	* rcu_read_lock_sched_notrace.
	75	*/
	76	rcu_read_lock();
	77	ppid = task_tgid_nr(current->real_parent);
	78	rcu_read_unlock();
	79	value->s64 = ppid;
	80	}
	81
b64bc438 MD	82	int lttng_add_ppid_to_ctx(struct lttng_ctx **ctx)
	83	{
	84	struct lttng_ctx_field *field;
b64bc438 MD	85
	86	field = lttng_append_context(ctx);
	87	if (!field)
09fec6b4	88	return -ENOMEM;
44252f0f MD	89	if (lttng_find_context(*ctx, "ppid")) {
	90	lttng_remove_context_field(ctx, field);
	91	return -EEXIST;
	92	}
b64bc438 MD	93	field->event_field.name = "ppid";
	94	field->event_field.type.atype = atype_integer;
	95	field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
a90917c3	96	field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
06254b0f	97	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
b64bc438 MD	98	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	99	field->event_field.type.u.basic.integer.base = 10;
	100	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	101	field->get_size = ppid_get_size;
	102	field->record = ppid_record;
f127e61e	103	field->get_value = ppid_get_value;
a9dd15da	104	lttng_context_update(*ctx);
b64bc438 MD	105	wrapper_vmalloc_sync_all();
	106	return 0;
	107	}
	108	EXPORT_SYMBOL_GPL(lttng_add_ppid_to_ctx);
	109
	110	MODULE_LICENSE("GPL and additional rights");
	111	MODULE_AUTHOR("Mathieu Desnoyers");
	112	MODULE_DESCRIPTION("Linux Trace Toolkit PPID Context");
13ab8b0a MD	113	MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
	114	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
	115	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
	116	LTTNG_MODULES_EXTRAVERSION);