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

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-context-vppid.c
 *
 * LTTng vPPID context.
 *
 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <lttng/lttng-events.h>
#include <ringbuffer/frontend_types.h>
#include <lttng/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,
		struct lttng_probe_ctx *lttng_probe_ctx,
		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.integer.size = sizeof(pid_t) * CHAR_BIT;
	field->event_field.type.u.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
	field->event_field.type.u.integer.signedness = lttng_is_signed_type(pid_t);
	field->event_field.type.u.integer.reverse_byte_order = 0;
	field->event_field.type.u.integer.base = 10;
	field->event_field.type.u.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);
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);
Commit	Line	Data
b7cdc182	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
9f36eaed	2	*
886d51a3	3	* lttng-context-vppid.c
b64bc438 MD	4	*
	5	* LTTng vPPID context.
	6	*
886d51a3	7	* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
b64bc438 MD	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/slab.h>
	12	#include <linux/sched.h>
	13	#include <linux/syscalls.h>
b5304713 MD	14	#include <lttng/lttng-events.h>
	15	#include <ringbuffer/frontend_types.h>
	16	#include <lttng/lttng-tracer.h>
b64bc438 MD	17
	18	static
	19	size_t vppid_get_size(size_t offset)
	20	{
	21	size_t size = 0;
	22
a90917c3	23	size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
b64bc438 MD	24	size += sizeof(pid_t);
	25	return size;
	26	}
	27
	28	static
	29	void vppid_record(struct lttng_ctx_field *field,
	30	struct lib_ring_buffer_ctx *ctx,
a90917c3	31	struct lttng_channel *chan)
b64bc438	32	{
90f96adf	33	struct task_struct *parent;
b64bc438 MD	34	pid_t vppid;
b64bc438 MD	35
90f96adf	36	/*
de544ea5 MD	37	* current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
de544ea5 MD	38	* the current thread nsproxy to perform the lookup.
90f96adf	39	*/
1638c9b4 MD	40
	41	/*
	42	* TODO: when we eventually add RCU subsystem instrumentation,
	43	* taking the rcu read lock here will trigger RCU tracing
	44	* recursively. We should modify the kernel synchronization so
	45	* it synchronizes both for RCU and RCU sched, and rely on
	46	* rcu_read_lock_sched_notrace.
	47	*/
	48
b64bc438	49	rcu_read_lock();
90f96adf	50	parent = rcu_dereference(current->real_parent);
de544ea5	51	if (!current->nsproxy)
90f96adf MD	52	vppid = 0;
	53	else
	54	vppid = task_tgid_vnr(parent);
b64bc438	55	rcu_read_unlock();
a90917c3	56	lib_ring_buffer_align_ctx(ctx, lttng_alignof(vppid));
b64bc438 MD	57	chan->ops->event_write(ctx, &vppid, sizeof(vppid));
	58	}
	59
f127e61e MD	60	static
f127e61e MD	61	void vppid_get_value(struct lttng_ctx_field *field,
79150a49	62	struct lttng_probe_ctx *lttng_probe_ctx,
f127e61e MD	63	union lttng_ctx_value *value)
	64	{
	65	struct task_struct *parent;
	66	pid_t vppid;
	67
	68	/*
	69	* current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
	70	* the current thread nsproxy to perform the lookup.
	71	*/
	72
	73	/*
	74	* TODO: when we eventually add RCU subsystem instrumentation,
	75	* taking the rcu read lock here will trigger RCU tracing
	76	* recursively. We should modify the kernel synchronization so
	77	* it synchronizes both for RCU and RCU sched, and rely on
	78	* rcu_read_lock_sched_notrace.
	79	*/
	80
	81	rcu_read_lock();
	82	parent = rcu_dereference(current->real_parent);
	83	if (!current->nsproxy)
	84	vppid = 0;
	85	else
	86	vppid = task_tgid_vnr(parent);
	87	rcu_read_unlock();
	88	value->s64 = vppid;
	89	}
	90
b64bc438 MD	91	int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
	92	{
	93	struct lttng_ctx_field *field;
b64bc438 MD	94
	95	field = lttng_append_context(ctx);
	96	if (!field)
09fec6b4	97	return -ENOMEM;
44252f0f MD	98	if (lttng_find_context(*ctx, "vppid")) {
	99	lttng_remove_context_field(ctx, field);
	100	return -EEXIST;
	101	}
b64bc438 MD	102	field->event_field.name = "vppid";
b64bc438 MD	103	field->event_field.type.atype = atype_integer;
ceabb767 MD	104	field->event_field.type.u.integer.size = sizeof(pid_t) * CHAR_BIT;
	105	field->event_field.type.u.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
	106	field->event_field.type.u.integer.signedness = lttng_is_signed_type(pid_t);
	107	field->event_field.type.u.integer.reverse_byte_order = 0;
	108	field->event_field.type.u.integer.base = 10;
	109	field->event_field.type.u.integer.encoding = lttng_encode_none;
b64bc438 MD	110	field->get_size = vppid_get_size;
b64bc438 MD	111	field->record = vppid_record;
f127e61e	112	field->get_value = vppid_get_value;
a9dd15da	113	lttng_context_update(*ctx);
b64bc438 MD	114	return 0;
	115	}
	116	EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);