[lttng-modules.git] / src / lttng-context-time-ns.c

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-context-time-ns.c
 *
 * LTTng time namespace context.
 *
 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *               2020 Michael Jeanson <mjeanson@efficios.com>
 *
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/nsproxy.h>
#include <linux/time_namespace.h>
#include <lttng/events.h>
#include <lttng/events-internal.h>
#include <ringbuffer/frontend_types.h>
#include <wrapper/vmalloc.h>
#include <lttng/tracer.h>

#if defined(CONFIG_TIME_NS)

static
size_t time_ns_get_size(void *priv, struct lttng_kernel_probe_ctx *probe_ctx, size_t offset)
{
	size_t size = 0;

	size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int));
	size += sizeof(unsigned int);
	return size;
}

static
void time_ns_record(void *priv, struct lttng_kernel_probe_ctx *probe_ctx,
		 struct lttng_kernel_ring_buffer_ctx *ctx,
		 struct lttng_kernel_channel_buffer *chan)
{
	unsigned int time_ns_inum = 0;

	/*
	 * nsproxy can be NULL when scheduled out of exit.
	 *
	 * As documented in 'linux/nsproxy.h' namespaces access rules, no
	 * precautions should be taken when accessing the current task's
	 * namespaces, just dereference the pointers.
	 */
	if (current->nsproxy)
		time_ns_inum = current->nsproxy->time_ns->ns.inum;

	chan->ops->event_write(ctx, &time_ns_inum, sizeof(time_ns_inum), lttng_alignof(time_ns_inum));
}

static
void time_ns_get_value(void *priv,
		struct lttng_kernel_probe_ctx *lttng_probe_ctx,
		struct lttng_ctx_value *value)
{
	unsigned int time_ns_inum = 0;

	/*
	 * nsproxy can be NULL when scheduled out of exit.
	 *
	 * As documented in 'linux/nsproxy.h' namespaces access rules, no
	 * precautions should be taken when accessing the current task's
	 * namespaces, just dereference the pointers.
	 */
	if (current->nsproxy)
		time_ns_inum = current->nsproxy->time_ns->ns.inum;

	value->u.s64 = time_ns_inum;
}

static const struct lttng_kernel_ctx_field *ctx_field = lttng_kernel_static_ctx_field(
	lttng_kernel_static_event_field("time_ns",
		lttng_kernel_static_type_integer_from_type(unsigned int, __BYTE_ORDER, 10),
		false, false),
	time_ns_get_size,
	time_ns_record,
	time_ns_get_value,
	NULL, NULL);

int lttng_add_time_ns_to_ctx(struct lttng_kernel_ctx **ctx)
{
	int ret;

	if (lttng_kernel_find_context(*ctx, ctx_field->event_field->name))
		return -EEXIST;
	ret = lttng_kernel_context_append(ctx, ctx_field);
	wrapper_vmalloc_sync_mappings();
	return ret;
}
EXPORT_SYMBOL_GPL(lttng_add_time_ns_to_ctx);

#endif
Commit	Line	Data
	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
	2	*
	3	* lttng-context-time-ns.c
	4	*
	5	* LTTng time namespace context.
	6	*
	7	* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	* 2020 Michael Jeanson <mjeanson@efficios.com>
	9	*
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/slab.h>
	14	#include <linux/sched.h>
	15	#include <linux/nsproxy.h>
	16	#include <linux/time_namespace.h>
	17	#include <lttng/events.h>
	18	#include <lttng/events-internal.h>
	19	#include <ringbuffer/frontend_types.h>
	20	#include <wrapper/vmalloc.h>
	21	#include <lttng/tracer.h>
	22
	23	#if defined(CONFIG_TIME_NS)
	24
	25	static
	26	size_t time_ns_get_size(void priv, struct lttng_kernel_probe_ctx probe_ctx, size_t offset)
	27	{
	28	size_t size = 0;
	29
	30	size += lib_ring_buffer_align(offset, lttng_alignof(unsigned int));
	31	size += sizeof(unsigned int);
	32	return size;
	33	}
	34
	35	static
	36	void time_ns_record(void priv, struct lttng_kernel_probe_ctx probe_ctx,
	37	struct lttng_kernel_ring_buffer_ctx *ctx,
	38	struct lttng_kernel_channel_buffer *chan)
	39	{
	40	unsigned int time_ns_inum = 0;
	41
	42	/*
	43	* nsproxy can be NULL when scheduled out of exit.
	44	*
	45	* As documented in 'linux/nsproxy.h' namespaces access rules, no
	46	* precautions should be taken when accessing the current task's
	47	* namespaces, just dereference the pointers.
	48	*/
	49	if (current->nsproxy)
	50	time_ns_inum = current->nsproxy->time_ns->ns.inum;
	51
	52	chan->ops->event_write(ctx, &time_ns_inum, sizeof(time_ns_inum), lttng_alignof(time_ns_inum));
	53	}
	54
	55	static
	56	void time_ns_get_value(void *priv,
	57	struct lttng_kernel_probe_ctx *lttng_probe_ctx,
	58	struct lttng_ctx_value *value)
	59	{
	60	unsigned int time_ns_inum = 0;
	61
	62	/*
	63	* nsproxy can be NULL when scheduled out of exit.
	64	*
	65	* As documented in 'linux/nsproxy.h' namespaces access rules, no
	66	* precautions should be taken when accessing the current task's
	67	* namespaces, just dereference the pointers.
	68	*/
	69	if (current->nsproxy)
	70	time_ns_inum = current->nsproxy->time_ns->ns.inum;
	71
	72	value->u.s64 = time_ns_inum;
	73	}
	74
	75	static const struct lttng_kernel_ctx_field *ctx_field = lttng_kernel_static_ctx_field(
	76	lttng_kernel_static_event_field("time_ns",
	77	lttng_kernel_static_type_integer_from_type(unsigned int, __BYTE_ORDER, 10),
	78	false, false),
	79	time_ns_get_size,
	80	time_ns_record,
	81	time_ns_get_value,
	82	NULL, NULL);
	83
	84	int lttng_add_time_ns_to_ctx(struct lttng_kernel_ctx **ctx)
	85	{
	86	int ret;
	87
	88	if (lttng_kernel_find_context(*ctx, ctx_field->event_field->name))
	89	return -EEXIST;
	90	ret = lttng_kernel_context_append(ctx, ctx_field);
	91	wrapper_vmalloc_sync_mappings();
	92	return ret;
	93	}
	94	EXPORT_SYMBOL_GPL(lttng_add_time_ns_to_ctx);
	95
	96	#endif