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

/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
 *
 * 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-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,
		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.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);
Commit	Line	Data
9f36eaed MJ	1	/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
9f36eaed MJ	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>
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 vppid_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 vppid_record(struct lttng_ctx_field *field,
	31	struct lib_ring_buffer_ctx *ctx,
a90917c3	32	struct lttng_channel *chan)
b64bc438	33	{
90f96adf	34	struct task_struct *parent;
b64bc438 MD	35	pid_t vppid;
b64bc438 MD	36
90f96adf	37	/*
de544ea5 MD	38	* current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
de544ea5 MD	39	* the current thread nsproxy to perform the lookup.
90f96adf	40	*/
1638c9b4 MD	41
	42	/*
	43	* TODO: when we eventually add RCU subsystem instrumentation,
	44	* taking the rcu read lock here will trigger RCU tracing
	45	* recursively. We should modify the kernel synchronization so
	46	* it synchronizes both for RCU and RCU sched, and rely on
	47	* rcu_read_lock_sched_notrace.
	48	*/
	49
b64bc438	50	rcu_read_lock();
90f96adf	51	parent = rcu_dereference(current->real_parent);
de544ea5	52	if (!current->nsproxy)
90f96adf MD	53	vppid = 0;
	54	else
	55	vppid = task_tgid_vnr(parent);
b64bc438	56	rcu_read_unlock();
a90917c3	57	lib_ring_buffer_align_ctx(ctx, lttng_alignof(vppid));
b64bc438 MD	58	chan->ops->event_write(ctx, &vppid, sizeof(vppid));
	59	}
	60
f127e61e MD	61	static
f127e61e MD	62	void vppid_get_value(struct lttng_ctx_field *field,
79150a49	63	struct lttng_probe_ctx *lttng_probe_ctx,
f127e61e MD	64	union lttng_ctx_value *value)
	65	{
	66	struct task_struct *parent;
	67	pid_t vppid;
	68
	69	/*
	70	* current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
	71	* the current thread nsproxy to perform the lookup.
	72	*/
	73
	74	/*
	75	* TODO: when we eventually add RCU subsystem instrumentation,
	76	* taking the rcu read lock here will trigger RCU tracing
	77	* recursively. We should modify the kernel synchronization so
	78	* it synchronizes both for RCU and RCU sched, and rely on
	79	* rcu_read_lock_sched_notrace.
	80	*/
	81
	82	rcu_read_lock();
	83	parent = rcu_dereference(current->real_parent);
	84	if (!current->nsproxy)
	85	vppid = 0;
	86	else
	87	vppid = task_tgid_vnr(parent);
	88	rcu_read_unlock();
	89	value->s64 = vppid;
	90	}
	91
b64bc438 MD	92	int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
	93	{
	94	struct lttng_ctx_field *field;
b64bc438 MD	95
	96	field = lttng_append_context(ctx);
	97	if (!field)
09fec6b4	98	return -ENOMEM;
44252f0f MD	99	if (lttng_find_context(*ctx, "vppid")) {
	100	lttng_remove_context_field(ctx, field);
	101	return -EEXIST;
	102	}
b64bc438 MD	103	field->event_field.name = "vppid";
	104	field->event_field.type.atype = atype_integer;
	105	field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
a90917c3	106	field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
06254b0f	107	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
b64bc438 MD	108	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	109	field->event_field.type.u.basic.integer.base = 10;
	110	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	111	field->get_size = vppid_get_size;
	112	field->record = vppid_record;
f127e61e	113	field->get_value = vppid_get_value;
a9dd15da	114	lttng_context_update(*ctx);
b64bc438 MD	115	wrapper_vmalloc_sync_all();
	116	return 0;
	117	}
	118	EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);