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

/*
 * lttng-context-vppid.c
 *
 * LTTng vPPID 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 vppid_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 vppid_record(struct lttng_ctx_field *field,
		  struct lib_ring_buffer_ctx *ctx,
		  struct lttng_channel *chan)
{
	struct task_struct *parent;
	pid_t vppid;

	/*
	 * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
	 * the current thread nsproxy to perform the lookup.
	 */

	/*
	 * 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();
	parent = rcu_dereference(current->real_parent);
	if (!current->nsproxy)
		vppid = 0;
	else
		vppid = task_tgid_vnr(parent);
	rcu_read_unlock();
	lib_ring_buffer_align_ctx(ctx, lttng_alignof(vppid));
	chan->ops->event_write(ctx, &vppid, sizeof(vppid));
}

static
void vppid_get_value(struct lttng_ctx_field *field,
		union lttng_ctx_value *value)
{
	struct task_struct *parent;
	pid_t vppid;

	/*
	 * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
	 * the current thread nsproxy to perform the lookup.
	 */

	/*
	 * 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();
	parent = rcu_dereference(current->real_parent);
	if (!current->nsproxy)
		vppid = 0;
	else
		vppid = task_tgid_vnr(parent);
	rcu_read_unlock();
	value->s64 = vppid;
}

int lttng_add_vppid_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, "vppid")) {
		lttng_remove_context_field(ctx, field);
		return -EEXIST;
	}
	field->event_field.name = "vppid";
	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 = vppid_get_size;
	field->record = vppid_record;
	field->get_value = vppid_get_value;
	lttng_context_update(*ctx);
	wrapper_vmalloc_sync_all();
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Linux Trace Toolkit vPPID 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-vppid.c
b64bc438 MD	3	*
	4	* LTTng vPPID 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 vppid_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 vppid_record(struct lttng_ctx_field *field,
	44	struct lib_ring_buffer_ctx *ctx,
a90917c3	45	struct lttng_channel *chan)
b64bc438	46	{
90f96adf	47	struct task_struct *parent;
b64bc438 MD	48	pid_t vppid;
b64bc438 MD	49
90f96adf	50	/*
de544ea5 MD	51	* current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
de544ea5 MD	52	* the current thread nsproxy to perform the lookup.
90f96adf	53	*/
1638c9b4 MD	54
	55	/*
	56	* TODO: when we eventually add RCU subsystem instrumentation,
	57	* taking the rcu read lock here will trigger RCU tracing
	58	* recursively. We should modify the kernel synchronization so
	59	* it synchronizes both for RCU and RCU sched, and rely on
	60	* rcu_read_lock_sched_notrace.
	61	*/
	62
b64bc438	63	rcu_read_lock();
90f96adf	64	parent = rcu_dereference(current->real_parent);
de544ea5	65	if (!current->nsproxy)
90f96adf MD	66	vppid = 0;
	67	else
	68	vppid = task_tgid_vnr(parent);
b64bc438	69	rcu_read_unlock();
a90917c3	70	lib_ring_buffer_align_ctx(ctx, lttng_alignof(vppid));
b64bc438 MD	71	chan->ops->event_write(ctx, &vppid, sizeof(vppid));
	72	}
	73
f127e61e MD	74	static
	75	void vppid_get_value(struct lttng_ctx_field *field,
	76	union lttng_ctx_value *value)
	77	{
	78	struct task_struct *parent;
	79	pid_t vppid;
	80
	81	/*
	82	* current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
	83	* the current thread nsproxy to perform the lookup.
	84	*/
	85
	86	/*
	87	* TODO: when we eventually add RCU subsystem instrumentation,
	88	* taking the rcu read lock here will trigger RCU tracing
	89	* recursively. We should modify the kernel synchronization so
	90	* it synchronizes both for RCU and RCU sched, and rely on
	91	* rcu_read_lock_sched_notrace.
	92	*/
	93
	94	rcu_read_lock();
	95	parent = rcu_dereference(current->real_parent);
	96	if (!current->nsproxy)
	97	vppid = 0;
	98	else
	99	vppid = task_tgid_vnr(parent);
	100	rcu_read_unlock();
	101	value->s64 = vppid;
	102	}
	103
b64bc438 MD	104	int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
	105	{
	106	struct lttng_ctx_field *field;
b64bc438 MD	107
	108	field = lttng_append_context(ctx);
	109	if (!field)
09fec6b4	110	return -ENOMEM;
44252f0f MD	111	if (lttng_find_context(*ctx, "vppid")) {
	112	lttng_remove_context_field(ctx, field);
	113	return -EEXIST;
	114	}
b64bc438 MD	115	field->event_field.name = "vppid";
	116	field->event_field.type.atype = atype_integer;
	117	field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
a90917c3	118	field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
06254b0f	119	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
b64bc438 MD	120	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	121	field->event_field.type.u.basic.integer.base = 10;
	122	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	123	field->get_size = vppid_get_size;
	124	field->record = vppid_record;
f127e61e	125	field->get_value = vppid_get_value;
a9dd15da	126	lttng_context_update(*ctx);
b64bc438 MD	127	wrapper_vmalloc_sync_all();
	128	return 0;
	129	}
	130	EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);
	131
	132	MODULE_LICENSE("GPL and additional rights");
	133	MODULE_AUTHOR("Mathieu Desnoyers");
	134	MODULE_DESCRIPTION("Linux Trace Toolkit vPPID Context");
13ab8b0a MD	135	MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
	136	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
	137	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
	138	LTTNG_MODULES_EXTRAVERSION);