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

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-context-ppid.c
 *
 * LTTng PPID 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 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,
		struct lttng_probe_ctx *lttng_probe_ctx,
		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.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 = ppid_get_size;
	field->record = ppid_record;
	field->get_value = ppid_get_value;
	lttng_context_update(*ctx);
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_ppid_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-ppid.c
b64bc438 MD	4	*
	5	* LTTng PPID 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 ppid_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 ppid_record(struct lttng_ctx_field *field,
	30	struct lib_ring_buffer_ctx *ctx,
a90917c3	31	struct lttng_channel *chan)
b64bc438 MD	32	{
	33	pid_t ppid;
	34
1638c9b4 MD	35	/*
	36	* TODO: when we eventually add RCU subsystem instrumentation,
	37	* taking the rcu read lock here will trigger RCU tracing
	38	* recursively. We should modify the kernel synchronization so
	39	* it synchronizes both for RCU and RCU sched, and rely on
	40	* rcu_read_lock_sched_notrace.
	41	*/
b64bc438 MD	42	rcu_read_lock();
	43	ppid = task_tgid_nr(current->real_parent);
	44	rcu_read_unlock();
a90917c3	45	lib_ring_buffer_align_ctx(ctx, lttng_alignof(ppid));
b64bc438 MD	46	chan->ops->event_write(ctx, &ppid, sizeof(ppid));
	47	}
	48
f127e61e MD	49	static
f127e61e MD	50	void ppid_get_value(struct lttng_ctx_field *field,
79150a49	51	struct lttng_probe_ctx *lttng_probe_ctx,
f127e61e MD	52	union lttng_ctx_value *value)
	53	{
	54	pid_t ppid;
	55
	56	/*
	57	* TODO: when we eventually add RCU subsystem instrumentation,
	58	* taking the rcu read lock here will trigger RCU tracing
	59	* recursively. We should modify the kernel synchronization so
	60	* it synchronizes both for RCU and RCU sched, and rely on
	61	* rcu_read_lock_sched_notrace.
	62	*/
	63	rcu_read_lock();
	64	ppid = task_tgid_nr(current->real_parent);
	65	rcu_read_unlock();
	66	value->s64 = ppid;
	67	}
	68
b64bc438 MD	69	int lttng_add_ppid_to_ctx(struct lttng_ctx **ctx)
	70	{
	71	struct lttng_ctx_field *field;
b64bc438 MD	72
	73	field = lttng_append_context(ctx);
	74	if (!field)
09fec6b4	75	return -ENOMEM;
44252f0f MD	76	if (lttng_find_context(*ctx, "ppid")) {
	77	lttng_remove_context_field(ctx, field);
	78	return -EEXIST;
	79	}
b64bc438 MD	80	field->event_field.name = "ppid";
b64bc438 MD	81	field->event_field.type.atype = atype_integer;
ceabb767 MD	82	field->event_field.type.u.integer.size = sizeof(pid_t) * CHAR_BIT;
	83	field->event_field.type.u.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
	84	field->event_field.type.u.integer.signedness = lttng_is_signed_type(pid_t);
	85	field->event_field.type.u.integer.reverse_byte_order = 0;
	86	field->event_field.type.u.integer.base = 10;
	87	field->event_field.type.u.integer.encoding = lttng_encode_none;
b64bc438 MD	88	field->get_size = ppid_get_size;
b64bc438 MD	89	field->record = ppid_record;
f127e61e	90	field->get_value = ppid_get_value;
a9dd15da	91	lttng_context_update(*ctx);
b64bc438 MD	92	return 0;
	93	}
	94	EXPORT_SYMBOL_GPL(lttng_add_ppid_to_ctx);