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

/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
 *
 * 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-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,
		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.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);
Commit	Line	Data
9f36eaed MJ	1	/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
9f36eaed MJ	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>
241ae9a8 MD	14	#include <lttng-events.h>
	15	#include <wrapper/ringbuffer/frontend_types.h>
	16	#include <wrapper/vmalloc.h>
	17	#include <lttng-tracer.h>
b64bc438 MD	18
	19	static
	20	size_t ppid_get_size(size_t offset)
	21	{
	22	size_t size = 0;
	23
a90917c3	24	size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
b64bc438 MD	25	size += sizeof(pid_t);
	26	return size;
	27	}
	28
	29	static
	30	void ppid_record(struct lttng_ctx_field *field,
	31	struct lib_ring_buffer_ctx *ctx,
a90917c3	32	struct lttng_channel *chan)
b64bc438 MD	33	{
	34	pid_t ppid;
	35
1638c9b4 MD	36	/*
	37	* TODO: when we eventually add RCU subsystem instrumentation,
	38	* taking the rcu read lock here will trigger RCU tracing
	39	* recursively. We should modify the kernel synchronization so
	40	* it synchronizes both for RCU and RCU sched, and rely on
	41	* rcu_read_lock_sched_notrace.
	42	*/
b64bc438 MD	43	rcu_read_lock();
	44	ppid = task_tgid_nr(current->real_parent);
	45	rcu_read_unlock();
a90917c3	46	lib_ring_buffer_align_ctx(ctx, lttng_alignof(ppid));
b64bc438 MD	47	chan->ops->event_write(ctx, &ppid, sizeof(ppid));
	48	}
	49
f127e61e MD	50	static
f127e61e MD	51	void ppid_get_value(struct lttng_ctx_field *field,
79150a49	52	struct lttng_probe_ctx *lttng_probe_ctx,
f127e61e MD	53	union lttng_ctx_value *value)
	54	{
	55	pid_t ppid;
	56
	57	/*
	58	* TODO: when we eventually add RCU subsystem instrumentation,
	59	* taking the rcu read lock here will trigger RCU tracing
	60	* recursively. We should modify the kernel synchronization so
	61	* it synchronizes both for RCU and RCU sched, and rely on
	62	* rcu_read_lock_sched_notrace.
	63	*/
	64	rcu_read_lock();
	65	ppid = task_tgid_nr(current->real_parent);
	66	rcu_read_unlock();
	67	value->s64 = ppid;
	68	}
	69
b64bc438 MD	70	int lttng_add_ppid_to_ctx(struct lttng_ctx **ctx)
	71	{
	72	struct lttng_ctx_field *field;
b64bc438 MD	73
	74	field = lttng_append_context(ctx);
	75	if (!field)
09fec6b4	76	return -ENOMEM;
44252f0f MD	77	if (lttng_find_context(*ctx, "ppid")) {
	78	lttng_remove_context_field(ctx, field);
	79	return -EEXIST;
	80	}
b64bc438 MD	81	field->event_field.name = "ppid";
	82	field->event_field.type.atype = atype_integer;
	83	field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
a90917c3	84	field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
06254b0f	85	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
b64bc438 MD	86	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	87	field->event_field.type.u.basic.integer.base = 10;
	88	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	89	field->get_size = ppid_get_size;
	90	field->record = ppid_record;
f127e61e	91	field->get_value = ppid_get_value;
a9dd15da	92	lttng_context_update(*ctx);
b64bc438 MD	93	wrapper_vmalloc_sync_all();
	94	return 0;
	95	}
	96	EXPORT_SYMBOL_GPL(lttng_add_ppid_to_ctx);